US1788719A - Combined switch and fuse cabinet - Google Patents

Description

Jan- 13, 1931 B. D. HoRToN 1,788,719

COMBINED SWITCH AND FUSE CABINET Filed Deo. 8, 1922 5 Sheets-Sheet l gli Z-"l' www Erwan Hor Zon.

59% vri/1,6%

Jan. 13, 1931. v B D, HORTON 1,788,719

'COMBINED SWITCH AND FUSE CABINET Filed Dec. 8, 1922 5 Sheets-Sheet 2 Jan. 1.3, 1931. I B. D. HORTON f 1,788,719

COMBINED SWITCH AND FUSE CABINET Filed Dep. 8, 1922 5 Sheets-Sheet 3 .f /Qg l I l I I I 3 I I I E 'ff J5 I E i I I i I I I r A"1 i I I 3 i 5 Il 3 I:l:' I I 70---Ir` l ""I Jan. 13, 1931. B. D. HoRToN COMBINED SWITCH AND FUSE CABINET 5 sheets-shea 4 Filed Deo. 8, 1922 Zdnarss/ @mgm Jan. 13, 1931. B. D. HoRToN COMBINED SWITCH AND FU-SE CABINET Filed Dec. v8, 1922 5 Sheets-Sheet 5 NSK Patented Jan. 13, 1931 UNITED sfrATEs PATENT OFFICE BRYSON D. HORTON, OF DETROIT, MICHIGAN, ASSIGNOR TO SQUARE D COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN COMBINED SWITCH AND FUSE CABINET Application led December 8, 1922. Serial No. 605,637.

. My invention relates to switches and more particularly to that type, commonly known as protected lor armor-clad wherein the switch elements and adjoining live parts of the circuit are housed. While I shall describe my invention as being particularly useful in connection with this type of switch, I do not intend to limit myself yto this use solely as it is apparent that my invention may have a wide lield of utility and adaptability wherever movable door cabinets are desirable, whether in' this art or in remote and nonanalogous arts.

It is commonly known that the demand for iron clad switches has increased in recent years, chiefly due to the rapidly increasing utilization of electrical power for industrial purposes. Armor-clad switches have been adopted mainly because they reduce the element of life hazard by completely housing the live and unprotected parts of the switch and of the circuit where the switch is inserted. In order to render this type of switch elective and to guard against unauthorized tampering therewith, an interlock is provided between the cover and switch, so that the cover can not be opened while the switch is closed, and the switch closed while the cover is open. Such`a construction is undesirable in many cases, especially in industrial plants where production can not be advantageously shut down in order to permit inspection of the switch atfrequent intervals. Accordingly, I have disclosed in United States Letters Patent,

1,412,242, issued on April 11, 1922, an interlock mechanism capa le of being disabled by a duly authorized erson, appointed to inspect the switch, so t at it is no longer 1mperative to discontinue service to the customer during inspection of the-switch. Incidentally, another difficulty arose in electrical transmission. It is well known that fuses should never be removed from the circuit unless the switch is opened to break the circuit, as a quick break at the fuse terminals is not provided for, and consequently the resultant arcing will burn the terminals. Another disadvantage lies in the fact that the fuses are apt to be removed at a time when current in the load line is imperative.

It is, therefore, an object of my invention to overcome these diliculties by providing in connection with the switch box cover interlock and disabling mechanism, means whereby the fuses are protected against unauthor- 1zed tampering, but so related with the interlock, that displacement of the fuses is prevented while the switch is in closed position.

It is a further object of my invention to provide a switch box having a switch and a fuse compartment with separated doors for each compartment, so that access to one com- -at no time while the switch is closed may the fuse displacement door be opened.

My invention further provides for permitting inspection of the fuses while the switch is closed. An inspection door, exposing to V1ew a limited area of the fuse compartment, is provided and so related with the switch door that whenever the switch door is opened, the fuse inspection door may be also opened.

According to the teachings of this invention, the interlock is constructed to prohibit the opening of the fuse displacement door while the circuit 'is closed, and therefore, removal of the fuses is rendered impossible when the switch is closed. The disabling means above described may be termed a switch and fuse inspection door disabling means, as distinguished from a second disabler which I provide as one of the objects of my invention, to render the locking of the switch in open position, by the interlock, in-

eiective, while the switch and fuse inspection doors are opened.

So far as I am aware, no attempt has heretoiore been made to provide for the inspection of the fuses and at the same time prohibit their displacement. Nor has there been an attempt to permit inspection of the switch and fuses while the switch is closed.

Accordingly, I believe that am the iirst to provide such a construction, and shall therefore claim the same broadly.

My invention in its broadest aspect involves the provision of a cabinet having doors thereon, and an interlock therefor, to permit opening of thev doors only when certain conditions have been fulfilled within the cabinet. t is not necessary that the interlock cooperate only with the doors of the cabinet, as interlocking of some other part of the cabinet may be desired, this being however, a substitute for a door and included within the scope of this invention.

A further object of my invention is the provision of a simple, compact and unitary interlock.

Another object is to construct this interlock so that it cooperates with the doors, only when they are in closed position.

Another object is to arrange the switch lock disabler so that when eiective, the fuse displacement door may not be opened, although the switch may be open.

Another object is to have the inspection doors and fuse displacement door cooperate independently with the interlock when they` are closed.

Another object is to accomplish the above by the provision of lock bars preferably parallel to the door openings, and to each other.

Another object is to associate said lock bars with the interlock so that each is independent in operation from the other.

ln order to apprise those skilled in the art how to construct and practice my invention, I shall describe an embodiment thereof in connection with the accompanying drawings which form part of the specification.

In the drawings:

Figure 1 is a perspective view of a cabinet embodying my invention, with all the doors in closed position; v

Fig. 2 is a similar view, illustrating the switch and fuse displacement doors in open position with the switch open;

Fig. 3 is also a similar view, but illustrating the switch closed "with the switch and fuse inspection doors released by means of a disabling key inserted at one side of the f cabinet;

Fig. 4 is a perspective view of the cabinet, showing the switch and fuse inspection doors released and a second disabling device in the same side of the cabinet for permitting the switch tobe released and closed while these doors are open.

Fig. 5 is a vertical sectional view through theY cabinet, looking in the direction of an interlock enclosed within a protective houslng S Fig. 6 is a detail view of the interlock in position when the switch and all the doors are closed;

Fig. 7 is a similar view or the interlock, butv illustrating it in a position when the switch is open and the doors are closed;

Fig. 8 is a similar view showing the interlock in position when the switch and all the doors are open; l

Fig. 9 is a similar view, illustrating the interlock in position when the switch is closed and the interlock is disabled to release the switch and fuse inspection doors;

Fig. 10 is a detail view oiE the same mechanism after the switch interlock has been rendered ineffective and the switch closed during the time the switch and fuse inspection doors are open;

Fig. 11 is a detail view taken on line ll-li looking in the direction of the arrows in Fig. 6;

Fig. 12 is a detail view taken on line 12-12 in Fig. 6, looking in the direction of the arrows;

Fig. 13 is a detail view taken on line 13-13 of Fig. 6.

A brief description of the cabinet embodying my invention will first be given in order that the adaptability of the interlock and disabling mechanism which permit the opening of the inspection doors at a time when the switch is closed, or the closing of the switch while these doors are open. will be under stood with greater facility. It is to be under stood that my invention is adaptable to various kinds of cabinets, whether in this or nonanalogous arts and I therefore do not intend l to limit myself solely to a cabinet having a switch and fuse unit carried therein.

Referring more particularly to Figs. 2 and 5 a cabinet 1 is provided on the rear wall thereof with a unit base construction for carrying the contacts of a switch unit 2. and the terminals of fuses connected to the switch. This unit base construction has been more fully disclosed in a copending application of Albert J. Ball, Serial No. 623,856, filed March 7, 1923, and I therefore deem it unnecessary to explain in greater detail the construction of this mounting other than stating that units 4', capable of individual displacement, carry the various live parts of the circuit, and that the units 4 are held in position by a grid 4 secured to the back wall of the cabinet by screws 8. The upper units 4 carry a plurality of service line terminals 5 and 6. which receive the service leads, not shown, in any suitable manner from the exterior of the cabinet. Co-operating terminal clips 7 are provided adjacent to the service terminals 5 and 6 on the upper units 4. for receiving the free end of switch blades 8. At the other end, the switch blades are pivotally carried by a second pair of terminal clips 8i', suitably v mounted upon a second set of units 4 disposed substantially midway on the grid 4. The switch, which I have shown, is of the quick break type so that a sudden break will take place between the terminal clips 7 and blades 8 to preventarcing and burning of the contacting surfaces. A switch handle 9 is suitably-journaled in the sides of the cabinet and is provided with an exterior operating handle 10 lying at one side of the cabinet. A pair of fuse terminal clips 11 is electrically connected to the switch terminal clips 8 on the middle units 4. Directly. below these terminal clips 11 is a second pair yof fuse terminal clips 12 disposed on a third set of units 4 at the lower end of the cabinet. Any suitable type of fuse may be employed in the present Construction. However, I have illustrated fuses 13 of the cartridge type adapted to bridge terminal clips 11 and 12.

When the doors are opened, the interior of the cabinet constitutes a single compartment. In order to separate the switch from the fuse when it is desired to open certain of the doors while the circuit is closed,`and as will be explained later, to prevent the removal of the fuses, I have provided a pair of fuse barriers 15 for lying across the terminal clips 11 and 12. These barriers comprise arms 16, extending from the inside face of a fuse displacement door 17, and having cross bars 18 of suitable insulation. Each cross bar 418 lies directly against one of the air offuse terminal clips when the door 17 1s closed, so that fuses 13 are locked in the circuit. It will be apparent that any form of partition may be used between the switch and fuses so that displacement access to the fuses cannot befhad should the switch door be opened while the circuit is closed. Access to the switch `is obtained through a door 20 closing over substantially the entire switch compartment. Fuse displacement door 17 hingedly carries a smaller door 22, which affords limited inspection of the fuses when opened. A latch 23 is provided on the interior of the fuse inspection.

door 22 in order 'to permit this door to norf mally remain closed on the fuse displacement door 17. This mechanism comprises -a sliding plate 24, having one side turned outwardly and projecting slightly to form a hook 25 for'engaging the inner marginal edge of the opening in door 17 Sliding plate 24 is controlled by a button 27 carried on the eX- terior of the door 22. Button 27 is provided adjacent a knob 28, so that upon gripping the knob, one of the fingers may be used to operate the button.

Adjacent the side of the cabinet from which the switch handle 10 protrudes, an interlock mechanism 30 is provided on the interior of the cabinet. This interlock mechanism is embodied in a suitable casing 31 to prevent unauthorized release thereof when one orl more lof the doors are opened". In other words, it is impossible to operate the interlock mechanism, except by the proper device, which in the present instance is `a suitable projection carried by each door. 'The casing 31 is provided with an arcuate slot 32, as shown in Fig. 5, to receive the rod 9 of the switch mechanism. In passing through the casing 31, rod 9 is adapted to interconnect with mechanism 30 so that the switch may be operated only when the doors are closed. However, I have made certain provisions in connection with this interlock to release the switch door 2O and the fuse inspection door 22 when the switch is closed, and also for releasing the switch when it is locked in open position when these two doors are open. It is to be understood that .this interlock will Jfunction to hold the switch in open position while the fuse displacement door 17 is open, and, vice versa, to hold the door 17 closed when the switch is closed.`

Referring now to Figs. 6 to 10 inclusive, I have shown the interlockl mechanism in the various positions: first, of locking the doors closed while the switch is closed, second, of

releasing all the doors when the switch isl open, third, of locking the switch open while the doors are open, fourth, of permitting certain of the doors to open while the switch is closed, and fifth, of releasing the switch to permit it to close while these doors are open.

The interlock 30 comprises essentially two parts, one for controlling the inspection doors 20 and 22, and the other for controlling the fuse displacement door 17. A lock bar 35 having translational movement in the casing 31 is carried by brackets 36 and 37 secured to the side ofthe cabinet. The upper end of this bar is cut at an angle and `passes through an opening in a depending eye plate 38 carried by switch door 20. When door 20 is closed, plate 38 is adapted to engage a projecting tongue 39 on an interconnecting bar 40. Bar 40 extends downwardly, and at the other end is formed with a similar tongue 41. Tongue 41 is adapted to be engaged by a depending eye plate 42 carried on fuse inspection door 22. Normally, the eye plate 42 is engaged by the lower end 43 of lock bar 35, this end 43 being in the form of aeU and turned back upon itself in order to lie in the same direction as the other end of bar 35, as shown in Fig. 13. When the doors 20'and 22 are closed, eye plates 38 and 42 will engage .the ends of bar 35 in snapped relation, to hold the doors in, closed position. In so doing,

plates 38and 42 engage and depress tongues 39 and 41 against the tension of springs 45 and 46, thereby forcing the bar 40 slightly outwardly. It is to be noted that the interconnecting bar 40 is carried in oating relation so that it is free to move when the tongues 39 and 41 are engaged and depressed. Bar 40 is carried within the casing 3l by a plate 47 guiding the upper end, and by the tongues 39 and 41 passing through suitable openings in the brackets 37 and 33 secured to the cabinet wall. Springs and 4G suitably connect at one of their ends to bar 40 and at their opposite end to plates 36 and 37. li switch lock 48 is suitably pivoted to the adjacent wall of the cabinet, and is provided with an engageable, hook-shaped locking finger 49. il spring 50 interconnects bar 40 with switch lock 43. ln moving outwardly, bar 40 permits the switch lock 43 to drop back by gravity, or it may drop back through a projecting stud anchored in the switch leek and riding on the edge of bar 40, for guiding the switch lock in its movement according to the position of this bar. Spring 50 connects bar 40 with switch element 48, however, to prohibit the switch element from lagging in following the movement of the bar, or if the element sticks, to give it positive movement. l

As will be presently explained, locking linger 49 of switch element 48 serves to lock the switch in open position, by lying within the locus of movement of a projection carried by the switch. A movable plate 51 is suitably carried 0n the switch rod 9. l shall hereinafter term this plate 51 a switch operated element in order to distinguish it from the switch mechanism proper. This switch operated element Serves as an interconnecting member between the switch mechanism and interlock, and is provided in V shaped form with the legs 53 and 54. The switch in mov ing from closed to open position, as will be seen in lligures 6 and 7, will move the leg 53 downwardly. An engaging lug 55 is suitably carried on leg 53. Lug 55 is provided with a right angular projection lying in the plane of switch lock 48. When the leg 53 moves downwardly, lug 55 will move past finger49, provided the interconnecting bar 40 has been moved outwardly by the eye plates 38 and 42, engaging the tongues 39 and 41, and the linger 49 withdrawn from the path of lug 55, either by gravity or through the assistance of the spring 50. Consequently, the switch may be operated without hindrance. From this description it will be noted that the interlock functions to release and allow the switch to move freely to on or olf positions while the doors 20 and 22 are closed, this being accomplished, as above explained, by switch lock 48 being displaced from the path of the switch projection or lug 55, through the interconnecting bar 40 moving outwardly by engagement with the eye plates on the inspection doors 20 and 22.

Lock bar 35 is provided with a pin 57 adapted to be engaged by leg 53 of the switch element 51, when the switch is open.

if/ssfrie spring 58 is disposed between bar 35 and wall of the cabinet, said spring being secured at one end to bracket 36 and at the other end to bar 35. Spring 58 functions to hold bar 35 normally in engagement with eye plates 38 and 42. ln opening the switch, leg 53 will come against pin 57, and if the handle 10 is not moved any farther, the spring 53 will hold bar 35 in engagement with the respective eye plates of switch door 17 and fuse inspectiondoor 22. llhus the spring held bar 35 may normally serve as a latch to hold the doors closed and prevent accidental release should it be desired to open the switch and not the doors. But, in order to release the doors 20 and 22, handle 10 is moved slightly farther, so that pin 57 is moved by the leg 53. This additional movement operates against the tension of spring 58, and withdraws both ends of bar 35 from engagement with plates 38 and 42, thereby releasing the switch door 20 and fuse inspection door 22.

As viewed in Figs. 2 and 4, the handle 10 in reaching its extreme downward movement may engage a plate 50 rigidly secured to the exterior of the cabinet and provided with one or more perforations therein. This plate may serve as a stop for the switch handle l0, and also as a means for receiving a suitable padlock should it be desired to lock the switch temporarily in open position. However, l have found it preferable to embody the stop in the interlock mechanism itself, to prevent the bar 35 from moving too far.

This stop is in the form of a pin 61 projecting through both sides of bar 35 and abutting the side of bracket. 37 through which this bar passes.

lhen the switch inspection door 2O and fuse inspection' door 22 are closed, either singly or together, eye plates 38 and 42 engage the angularly cut ends of lock bar 35, forcing the bar slightly downward until the ends snap into the eyes in these plates, to hold the doors closed. The extending tongues 39 and 41 are forced inwardly until the interconnecting'bar 40 is moved sufciently to brin or allow switch lock 48 to drop backwar ly about its pivot point 65 in ordervfor its finger 49 to clear the lug 55. llt is to be noted that engagement of one of the tongues 39 or 41 will not be effective in moving interconnecting bar 40 a sufficient distance to withdraw the linger 49 of the switch lock 48. Hence, both inspection doors must be closed before the switch may be closed.

That part of the interlock which locks the fuse displacement door 17 will now be described. As above pointed out, lock bar 35 functions to interlock the inspection doors 20 and 22. I preferably employ a separate lock bar 70, similar to the bar 35, for interlocking with the fuse displacement door. However, this is not essential and the individuality of operation between the inspection doors and fuse displacement door may be' eliminated. This individuality in operation Ais desirable as it permits the use of disabling bar 70 and a bracket 71 also suitably secured,`

say to the cabinet wall, supports the upper end. When the fuse displacement door, 17

is closed, a. spring 72 tends to hold bar 70 raised in its upper position. A suitable stop, such as screw 73, may be provided on bar 70 to limit the upward motion thereof. At a point where the fuse displacement door 17 interlocks with lock bar 70, namely, the lower end thereof, a spring pressed latch 74 is provided. Latch 74 functions to hold the lock bar retracted while the fuse displacement door 17 is open. The action-of latch 74 is against the action of spring 72, consequently when-an eye plate 75 carried by the fuse displacement doorl engages latch 74 and releases it from lock bar 70, the lock bar will move to upper position. In so doing, the angularly cut end bf bar 70 will pass into the eye of plate 75, and will hold the fuse displacement door closed. In Fig. 8, I have shown the position of latch 74 and lock bar 70 when the fuse displacement door is open. It is apparent from this showing that the latch 74 `extends a sufficient distance beyond the angularly cut end of bar 70 to be engaged by eye plate 75 when the door is swung closed. Eye plate 75 willflip the latch 74 from engagement with a cross member 76, or other suitable extension, on the lower end of the lock bar 70. f

The upper end of lock bar 70 is provided witha pin v77, which is adapted to be engaged by leg 53V of switch element 51 when the l switch is opened. As before explained in connection with the releasing of the switch and fuseinspection doors .20 and 22, the lswitch will be brought to open position as the leg abuts and moves pin 57. I have provided the pin 77 on lockv bar 70 so that substantially the same action is obtained. If' it is desired to open the fuse displacement#` door 17 when the switch is open, continued movement of the exterior switch handle 10 is preferably required so that leg 53 of switch element 51 engages the pin 77to move bar 70a sutlicient distance downwardly. It is to be noted that no other provision has been made for moving bar 70, consequently the fuse displacement door 17 can be opened only when the switch is open.

In Fig.l 7, I have shown the position of the various' parts of the interlock when the switcli'is open and all the doors are closed.

" In this position, the angularly cut ends 'of lock bars and 70 serve as a latch for holdi ing the respective doors closed, but in a condition to be opened if switch handle 10 is given the additional movement required to move the lock bars 35 and 70 far enough for these ends to clear the eye plates on the doors.A It is understood that this additional movement is not essential to the essence of my invention, but is merely preferable as it prohibits the doors from iying open as the handle 10 is brought downwardly to open the switch. It merely serves to simplify the arrangement as practice has proven that some form of latch mechanism should be provided, so that it is not necessary to have the doors open every time the switch is opened.

In Fig. 8, I have shown the various parts of the interlock in their position when all of the doors are open. As above pointed out, springs and 46 serve to move the interconnecting bar toward the door openings, so that tongues 39 and 41 `will be extended through brackets 36 and 37 a maximum distance. In moving toward the door openings, interconnecting bar 40 tilts switch lock 48 forwardly about its pivot 65, by engaging pin carried on the switch lock. Thus the finger 49 of the switch lock is thrown in the path of lug 55 carried on switch element 51. In this position of the switch, lug 55 is within the re-entrant portion of finger 49. In order Ito prevent the switch from being forced to closed position by bringing lug 55 against finger 49 and forcing it about its pivot vto permit the lug to clear the finger, switch lock 48 is provided with an extension 80, which abuts against a lateral projection 81 on' lock bar 35. kAt the extreme lower end of lockbar 35, a lug in the form of a screw 82 is provided for abutment against the under- 49, with the result that the two members' are interlocked and the linger is held from movement.

I shall now describe the disabling device for rendering the interlock 30 ineffective with respect to the switch inspection door 20 and fuse inspection door 22. Assume thatthe interlock mechanism is in a position as shown in Fig. 6, that is, the doors are closed andthe switch is closed.y It may be desirable, when the device is in this condition to vobtain access to the interior of the cabinet for inspecting `the switch in order to ascertain the condition of the switch terminals, or to obtain access to the fuses for inspection purposes only. In order to obviate the necessity of throwing the switch to open position, I have provided a disabl'er 90 for releasing the switch and fuse inspection doorsing bracket 104,

while the switch remains closed. The disabler comprises a rotatable barrel 91 suitably lcarried on the side of the cabinet adjacent the interlock mechanism 30. As viewed in Figs. 3 and 9, a key 92 is adapted to be inserted in this barrel by passing through a slot 93, partly in the wall ot the cabinet and partly in the projecting portion of the barrel. A recess 94 is provided in lock bar 35 and a shoulder 95 thereby formed for receiving a ward 96 of the key 92. Movement of the key in a counterclockwise direction, as viewed in Fig. 3, will bring ward 96 against shoulder 95 and move lock bar 35 against the tension ot spring 58. The lock bar is thereby withdrawn from engagement with eye plates 38 and 42 carried by the switch and fuse inspection doors, respectively. Thus these doors are released and may be snapped open to permit the desired inspection of either the switch or fuses, as shown in Fig. 9.

As soon as the doors are thrown open, the eye plates of course disengage from tongues 39 and 41 and allow interconnecting bar 40 to move forwardly, and as a result bring iinger 49 forwardly to lie in the path of lug 55. If the switch s ould now be thrown open, lug will engage the upper portion and depress finger 49 out of its path. Finger 49 is free to move about the pivot as the lug 55 depresses the same by forcing the interconnecting bar 40 slightly outward by means of pin 60. As soon as lug 55 has cleared finger 49, the latter will again be brought forward by means of the springs 45 and 46. Thus the interlock is placed 1n a condition to permit release of the fuse displacement door 17, but only by continued movement of the switch handle 10. Lock bar will move against the tension of spring 72, through the engagement of leg 53 with pin 77.

However, if it is not desired to open the fuse displacement door -17 but to close the switch'again while the switch inspection door 20 and fuse inspection door 22 are open, the interlock may be rendered ineffective by l means of a second disabler 98, which I shall now describe.

InlFigs. 3 and 10, I have shown the switch cabinet with the switch and fuse inspection doors 20 and 22 open, and the switch closed. This particular condition has been ei'ected by means of disabler 98 after the switch doors were opened by throwing the switch to off position, as shown in Fig. 4. Disabler 98 comprises a movable barrel 99, suitably carried within the cabinet and protruding slightly from one side thereof.l A key 100 may be inserted in the protruding portion of the barrel when the slot therein registers with a slot- 101 cut inthe wall ot the cabinet. .Wards 102 of key 100 are adapted to engage a pivotal arm 103. Arm 163 is carried upon a projectreferably mounted on lock bar 70. In disabling the switch, the arm 103 is thrown forwardly to engage a projection 105 on the switch lock 48. Continued movement of arm 103, which results from further movement of key 100, will swing the switch lock about its pivot 65 so as to disable the tin-V ger 49 from the path of lug 55. As shown in Fig. 10, the switch may then be moved to closed position with the switch and fuse inspection doors open.

' It is to be noted that the function of disabler 98 is to trip the switch lock 48 out of locking position with the switch. That is, the switch lock. is moved sufficiently about its axis to permit the switch to havey free movement, either in being brought to closed position or to open position. l

Vith switch lock 48 held in this position by disabler 98, it is impossible to open the fuse displacement door, even though the switch may be open. If the fuse displacement door were permitted to open at this time, it is readily apparent that the switch could then be closed again and the fuses exposed to displacement access while the circuit is closed. This is prevented by arm 103 holding projection 105 against any thrust that may be imposed thereagainst by arm 53 engaging pin 57 on the lock bar 35, and the lock bar in turn bringing the lateral projection 81 against the member 80 of the switch lock 48. Only intended release of arm 103 from en gagement with projection 105 will restore switch lock 48 to a condition where it will again normally function. After the key 100 is withdrawn from the disabler 98, arm 103 is returned to its former pbsition by means of a suitable spring 107.

Keys 92 and 100 may be identical or they may be different, so that an inspector of one class may inspect the switch and fuses and report their' condition to an inspector of another class. Thus repairing the switch and fuses may be entrusted to a more capable man in order to reduce accidents, usually due to lnegligence of a careless inspector.

Padlocks 112 may be provided to lock the switch door 20 and fuse displacement door 17 permanently closed. These padlocks engage in .openings in hasps 114 suitably secured within the cabinet 1,

It is, of course, to be understood that I do not contemplate, in every instance, the use of two disabling mechanisms, or three doors as arranged herein. Theinterior of cabinet 1 in the present embodiment is continuous from end to end when al1 the doors are open, a strap .1x10 being provided midway merely to increase the rigidity of the cabinet and to serve as a support along one edge forA the doors 17 and 20 when closed. It is apparent that two permanently divided .compartments are possible in connection with the present dlsclosure, but certain advantages liein this open arrangement, one of which may be mentioned as being the ease with which it is possible to obtain access to the switch and fuse units, when it is desired to remove or repair the same.

I especially wish to emphasize that it is within the scope of the invention to extend the locking function of the mechanism 30 to lock various electrical attachments which it is possible to associate with a switch cabinet.

I do not intend to limit myself to the details disclosed and described, particularly with reference to the manner of assembling and arranging the various parts, as it is quite obvious that it is possible to obtain a combined switch and fuse cabinet having interlocking doors, as is contemplated within the scope of the present invention, by various arrangements which may constitute mere equivalency of that which is herein disclosed.

I claim:

l. In combination, a switch, fuses in circuit with said switch, a housing provided with doors movable to aford access to said switch and said fuses, an interlock preventing the opening of said doors while said switch is closed and the closing of said switch while said doors are open, and means for disabling said interlock to permit said switch door to open while the switch is closed.

2. In combination, a switch, fuses in circuit with said switch, a housing provided with a door to afford access to said switch and a door to afford access to said fuses, an interlock for preventing the opening of either door while said switch is closed land the closing of the switch while said doors are opened, and means for disabling said interlock for permitting the switch door to open while the switch is closed, said interlock having means holding said fuse door in locked position upon operation of said disabling means.

3. In combination, a switch and fuses in the switch circuit, a housing provided with doors movable to aiord access to said switch and said fuses, an interlock for preventing the opening of said doors while said switch is closed, and means for disabling the interlock whereby the switch door may be opened while the switch is closed.

4. In combination, a switch, fuses in circuit with said switch, a housing provided with doors movable to afford access to said switch and said fuses, an interlock for preventing the opening of said doors while said switch is closed, and means for disabling the interlock to permit access to said switch while closed, said interlock associated with said switch to prevent access to said fuses while the switch is closed.

5. Incombination, a switch, fuses in circuit with said switch, a housing for said switch and said fuses, movable doors provided on said casing for affording access to said switch and said fuses individually, an interlock for said doors and said switch whereby the doors may not be opened while the switch is closed, said interlock having dis abling means for releasing one of said doors while the switch is closed.

6. In combination, a switch, fuses in circuit with said switch, a housing for said switch and lsaid fuses, movable doors provided on said casing for affording access to said switch and said fuses, an interlock for said switch and said doors whereby theswitch remains locked in open position while the doors are open, and means for disabling said switch lock while one of said doors is open.

7. In combination, a switch, fuses in circuit with said switch, a housing for said switch and said fuses, movable doors provided on said housing for affording access to said switch and said fuses, an interlock for said switch and said doors whereby the switch remains locked in open position while the doors are open, and means for disabling said switch lock while said switch door is open. v

8. In combination, a switch, fuses in circuit with said switch, a housing for said switch and said fuses, movable doors provided on said housing for affording access to said switch and said fuses, an interlock for said switch and said doors whereby the switch remains locked in open position while the doors are open, and means for disabling said switch lock to permit operation of the switch while said switch door is open, said disabling means being inoperative while said fuse door remains open.

9. In combination, a switch, a plurality of fuses, a housing` for said switch andl said fuses, movable doors provided on said housing for affording access to said switch and said fuses, an interlock for said switch and said doors whereby the switch remains locked in open posit-ion while the doors are open,'

and means for disabling said switch lock to permit operation of the switch while said switch door is open, said interlock rendering said disabling means inoperative as long as said fuse door is open.

10. In combination, a switch, fuses in the circuit therewith, a housing for saidswitch and said fuses, movable doors provided on said housing for affording access to said switch and said fuses, an interlock for said switch and said doors whereby the switch remains locked in open position while the doors are open, and disabling means associated with said interlock capable of rendering the switch lock ineii'ective upon said fuse door being moved to closed position.

11. In combination, a switch and a plurality of fuses, a housing for said switch and said fuses, movable doors provided on said housing for affording access to said `switch and said fuses, an interlock between said switch and said doors lor preventing the closing of the switch until the doors have been closed and the opening of the doors until the switch is opened, disabling means for rendering said interlock ineffective to permit opening of the switch door while said switch is closed whereupon the switch may be opened, and a second disabling means for permitting closing of said'switch while said switch door is open.

l2. ln combination, a switch and a plurality of fuses, a housing for said switch and said fuses, movable doors provided on said housing for affording access to said switch and said fuses, an interlock between said switch and said doors for preventinea the closing of the switch until the doors nave been closed, a disabling device for said interlock to permit closing of the switch while one of said doors remains open, and a second disabling device for said interlock to permit opening of said door while the switch is closed.

13. ln combination, a switch and a plural-l` ity of fuses in circuit therewith, a housing for said switch and said fuses, movable doors provided on said housing for affording access to said switch and said fuses, means for preventing the opening of either door until the switch is open and the closing of the switch until the doors have been closed, keylike means Yfor rendering said means ineffective to permit access to said switch in closed position, and key-like means for permitting the operation of said switch while the switch door is open.

14. ln combination, a switch, a plurality of fuses, a housing for said switch and said fuses, movable doors provided on said housing 'for ail'ording access to said-switch and said fuses, an interlock between said switch and said doors for preventing the closing of said switch u'ntil the doors are closed, and key-like means for disabling said interlock after said fuse-door is closed but while said switch door is open to close said switch.

l5. ln combination, a switch, a plurality of fuses, a housing for said switch and said fuses, an interlock between said switch and said doors for preventing the closing of said switch until the doorsareg closed and the opening of the doors until the switch is opened, key-like means for disabling said interlock to permit opening of said switch door while said switch is closed, and a second key-like disabling member for said interlock whereby the switch may be closed while the switch door remains open.

16. In an electrical cabinet'having a plu-` rality of movable doors, an interlock for preventing the opening of said doors until the circuit is broken, disabling means 'for releasing certain of the doors, said disabling means being operatwe only when said interlock is engaged by one of said doors,

mesme Lcircuit operating means while the circuit is closed, and means for disabling said interlocking means to permit the opening of certain of the doors.

i8. in an electrical cabinet having a plurality of movable doors, means operated from the exterior of said cabinet for controlling the opening and closing oi' a circuit within said cabinet, an interlock between said doors and said circuit controlling means for preventing movement of the doors from closed position while the circuit is closed, and means for disabling said interlock with respect to certain of the doors so that they may be opened while thecircuit is closed.

i9. ln an electrical cabinet having a plurality of movable doors, means for controlling the opening and closing of a circuit from the exterior of lsaid cabinet, an interlock between said doors and said circuit controlling means for preventing the closing of the circuit until said doors are closed, and means for disabling said interlock to permit said circuit to be closed while certain of the doors remain open.

20. In an electrical cabinet having a plurality of movable doors, means for controlling the opening and closing of a circuit with said cabinet, an interlock between said doors and said circuit controlling means for preventing the closing of the circuit until the doors are closed and the opening of the doors until the circuit is opened, and means 'lor rendering said interlock ineffective with respect to certain of said doors and said circuit controlling means.

2l. ln an electrical cabinet having a plurality of movable doors, means 'for controlling the opening and closing of a circuit within said cabinet, an interlock between said doors and said circuit controlling means 'for preventing the closing of the circuit until the doors are closed and the opening of the doors until the circuit is opened, disabling means for rendering said interlock ineilective to permit the opening of certain of said doors while the circuit is closed, and a second disabling means for rendering said interlock ine'ectiveto permit the closing of the circuit while certain of said doors remain open.

22. In an enclosed switch having fuses in circuit therewith, the combination of doors and switch mechainsm, said doors affording switch and fuse access and fuse inspection, interlocking means associated with said switch mecliainsm and cooperating with said doors to prevent removal of said fuses while the switch is closed, and means associated with the fuse inspection door to permit inspection of said fuses during the time said switch is closed.

switch and fuse access and fuse inspection,

interlocking means associated with said switch mechanism and cooperating with said doors to prevent access either to the switch or to the fuses until the circuit is broken, and

means associated with 'the fuse inspection door to permit limited inspection of the fuses durin the time the circuit is closed.

25. n an enclosed switch having fuses mounted within the enclosure, the combination of interlocking doors including a fuse displacement door and switch controlled mechanism whereby said fuse displacement door can not be opened until the circuit is broken, and means for permitting inspection i of saidfuses While said circuit is closed by openin lone door.

26. n combination, a switch, a housing thereforfuses within said housing, three doors provided on said housing two of which permit inspect-ion of the switch and fuses and the third door displacement of the fuses,

'an interlock for normally preventing the opening of the doors until the switch has been opened, and means for rendering said interlock ineffective with respect to said inspection doors.

27. In combination, a switch, a housing therefor having fuses therein, movable doors on said housing for'permitting inspection of said switchl and said fuses and displacement l of the latter, an interlock between the switch and said doors for preventing opening of either until the switch is opened, and disabling means for rendering said interlock ineffective with respect to said inspection doors whereby said switch and said fuses may be I inspected while the switch is closed.

28. In combination, a switch, a housing therefor having fuses therein, movable doors on said housin for permitting inspection of said switch and inspection and displacementof said fuses, interlocking mechanism for circuit therewith, the combination of a said interlock to permit closing of said switch while the inspection doors remain open.

30. In combination, a switch, a housing therefor having fuses therein, movable doors on said housing for permitting inspection of said switch, inspection of said Jfuses and displacement of the latter, an interlock between all of said doors and said switch for preventing the closing of the switch untilthe doors are closed and the opening of the doors until the switch is opened, and disabling devices for rendering said interlock ineective to permit independent operation of said inspection doors with respect to said switch.

31. In combination, a. switch, a housing therefor lhaving fuses therein, said housin having individual doors movable to atfor inspection of said fuses and said switch and displacement of said fuses, an interlock between said doors and said switch for preventing the opening of said doors until the switch is opened, and means for releasing said inspection doors independent of the position of said switch.

32. In an enclosed switch having useslin urality of fuse and switch inspection and use displacement doors, switch operating means Ainterlocking with said doors while said switch is closed, said inspection doors being interrelated With each other so that they may be released from said switch operating means by a single disabling device.

33. In an enclosed switch having fuses in circuit therewith, the combination of a plurality of movable doors for permitting individual inspection of said switch and said fuses and displacement of the latter, an interlock between said switch and said doors for normally locking the doors in closed position until the switch is opened, said interlock having a separate connection with s aid displacement door to prevent the opening thereof while said switch is closed irrespec- .tive of the condition of the other doors.

34. In combination, a switch, fuses in circuit with said switch, an enclosure for said switch and said fuses, movable doors on said enclosure for permitting individual ins ction of said switch and fuses, an inter ook for preventing the opening of said doors while said switch is closed, said interlock including a `lock bar common to both of said doors.

35. In combination, an electrical cabinet having a circuit controlling member therein and fuses in the circuit, doors for'afording access to the interior of said cabinet and for permitting individual inspection of the switch and fuses, and an vinterlock for preventing the opening'of said doors while the circuit is closed, said interlock comprising a lock bar common to said doors and lying parallel therewith when the doors are closed.

circuit is closed, said interlock having a lock bar common to said covers, said lock bar having movement in a plane transverse to the door openings.

37. In combination, an electrical cabinet having a circuit controlling member therein, a plurality of doors on said cabinet movable to afford access to t-he interior of the cabinet and for permitting individual inspection ofl the switch and fuses, a lock'bar common to said doors having translatory arallel movement to the doors when close and mechanism between said circuit controlling' member and said lock bar for reventing movement of the bar when the circuit is closed.

38. In combination, an electric switch havingfuses associated therewith-a casing for said switch and fuses,- doors in said casing adapted'to afford access to the switch and fuses for inspection thereof, a lock bar common to said doors and housed within said casing to prevent access to said lock bar, and mechanism connected with said lock bar for locking said switch in open position while said doors are open.

39. In combination, an enclosed switch having fuses associated therewith, doors adapted to afford access vto the interior thereof for inspection of said switch and fuses, a lock bar common to said doors for reventing access to said switch and fuses w ile the switch' is closed, said lock bar serving as a latch for temporarily holding said doors closed but not locked when said switch is open, and a connection between said switch and said lock bar.

40. In combination, an enclosed switch havin fuses associated therewith, three doors twoo which afford inspection of the switch and fuses and the other displacement access to the fuses, an interlock for preventing the opening of said doors while said switch is closed, said interlock having a lock bar common to the inspection doors and a lock bar individual to the fuse displacement door.

41. In combination, an enclosed switch having fuses associated therewith, three doors two of which afford inspection of the switch and fuses and the other displacement access to the fuses, a lock'bar common to said inspection doors for locking the same closed while the switch is closed, a second lock bar for lockin said displacement access door closed whi e the switch is closed, said lock bars being so related to said switch that the release of said inspection doors will not affect the release of said displacement access door if the switch is closed.

42. In combination, an enclosed switch hav- I insane l ing fuses asociated therewith, three doors two of which afford inspection of the switch and fuses and the other displacement access to the uses, an interlock between said switch and said doors for preventing the opening of the doors while the switch is closed and the closing of the switch while the doors are open, said interlock comprising individual locking means for said inspection doors and said displacement access door whereby the inspection doors may be operated independently of the displacement access' door.

43. In combination, anfenclosed switch having fuses associated therewith, a pair of doors for affording inspection of said switch and fuses and adapted to be locked and released together, a third door for affording displacement access to said fuses and adapted to be locked and released separately, and means between said switch and said doors for effecting the locking and releasing of the doors.

44. In comination, an enclosed switch having fuses associated therewith, a pair of doors for affording inspection of said switch and fuses, and adapted to be locked and released together, a third door for affording displacement access to said fuses and adapted to be locked and released separately, a lock bar common to said pair of doors and connected to said switch through an interlock, and a second lock bar for said third door and also connected to said switch through said interlock, said interlock being separately related to said bars.

45. In combination, an enclosed switch having fuses associated therewith, a pair of doors for affording inspection of said switch and fuses, a third door for aiiording displacement lof said fuses, an interlock between said doors and said switch, said interlock including a pair of bars, one for the inspection doors and the other for the fuse displacement door, said bars being movable in substantially parallel planes.

46. In combination, an enclosed switch having fuses in circuit therewith, a door for inspecting the switch and a door for inspecting the fuses, a third door for permitting displacement of the fuses, and mechanism for permitting the opening of the inspection doors separate from the opening of the displacement door and only' when said switch is open, said mechanism including a pair of lock bars normally serving as spring operated latches for holding said doors closed.

47. In combination, an enclosed switch having fuses associated therewith, a door for inspecting the switch and a door for inspecting the fuses, a third door associated with the fuse inspection door for permitting displacement of the fuses, mechanism for releasing the inspection doors from closed position as the switch is opened, said mechanism also releasing said fuse displacement door when said switch is open, and means `included in said mechanism for rendering independent releasing of said inspection doors.

48. In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses, a displacement door for said fuses, an interlock including lock bars for locking the doors closed, spring means for normally holding said bars in locking position, and means on saidv switch for engaging and moving said bars against the tension of said spring means for releasing the doors.

49. In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses, a displacement door for said fuses, an interlock for preventing the opening of said doors while said switch is closed and the opening of the switch while the doors are open, an interlock including parallel lock bars influenced into engaging position with said doors by spring means, said bars being engaged for movement against said spring means by said switch as it moves to open position whereby the doors are free to open.

50. In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and said fuses, an interlock between said switch and said doors, said interlock provided with common means for locking said doors so that the doors may l not be opened while the switch'is closed, and

a disabler for operating said locking means whereby the doors may be opened while the switch is closed.

51.v In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses, an interlock between said switch and said doors, said interlock including a lock bar common to said doors'for preventing the opening of the doors while the switch is closed, said lock bar normally being adapted for movement by the switch to release said doors, and means independent of the movement of the switch for operating said lock bar.

52. In4 combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses,`an interlock between said switch and said doors, said interlock including a common lock bar normally urged to engaging position with said doors, and a projection on said switch adapted to engage and move said bar out of engaging relation with said doors. when the switch is opened.

53. In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses, an interlock between said switch and said doors, said interlock including a common lock bar normally urged to engaging position with said doors, a projection on said switch adapted to engage and move said bar out of engaging relation with said doors when the switch is open, and

key means for engaging and moving said lock bar against its tendency to remain ln-locking position while said switch is closed.

54. In combination, an enclosed switch having fuses associated therewith, inspec` tion doors for said switch and fuses, an interlock between said switch and said doors for preventing the closing of the switch while the doors are open, said interlock comprising a locking member common to said doors and a switch lock adapted to obstruct the movement of the switch while the doors are open, and an interconnecting bar movable by the closing of said doors for withdrawing said switch lock.

55. In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses, an interlock between said switch and said doors for preventing the closing of the switch while the doors are open, said interlock comprising a locking member common to said doors and a switch lock adapted to obstruct the movement of the switch while the doors are open, an interconnecting bar movable by the closing of said doors for displacing said switch lock, and disabling means for displacin Y said switch lock while the doors are yopen w ereby the switch may be closed. j ,l

56. In combination, an lenclosed switch having fuses associated therewith, inspection doors for said switchand fuses, an interlock between said switch and said doors for preventing the opening of the doors while the switch is closed, said interlock comprisinga locking member common tov said doors and normally urged to locking position by spring means, a projection on said switch adapted as the switch is moved to open position to -engage and move said bar to release said doors, and means lndependent of said projection for moving said locking member.

57. In combination, an enclosed switch having fuses associated therewith, inspection doors for said switch and fuses, an interlock between'said switch and said doors for preventing the opening of the doors while the switch is closed, said interlock comprising a member engaging each door when closed and being normally urged to locking posiy tion, a pin on said member, and a projection carried on said switch adapted as the switch is moved to open position to engage said pin -and move said member '.to releasing position. 58. In combination, an enclosed switch lhaving fuses associated therewith," "inspection doors for said switch and fuses, an interlock `between said switch and said doors for preventing the opening of the doors while the switch is closed, said interlock comprising a member engaging each door when closed and being normally urged to locking position, a pin on said member, a projection carried on said switch adapted as the switch is moved to open position to engage said pin and move said member to releasing position, and means operable from the exterior of said enclosure for directly engaging said member to release said doors.

59. In combination, an `enclosed switch fuses associated therewith, inspection doors for said switch and fuses, an interlock between said switch and said doors for preventing the opening of the doors while the switch is closed andthe closing of the switch while the doors are open, said interlock comprising a common lock bar for said doors and an interconnecting member engageable by each door as it is closed, a switch lock controlled by said interconnecting member and adapted to lie in the path of movement of said switch when the doors are open, the movement of said switch to open position releasing saidl doors whereupon the switch lock is projected into the path of movement of the switch as the doors disengage said interconnecting member.

60. In combination, an enclosed switch having fuses associated therewith, inspection doors for' said switch and fuses, an interlock between said switch and said doors for predetermining the movement of both the switch and the doors, means included in said interlock for releasing saidswitch from open position as the doors are closed, said means rendered effective to hold the switch in open position by disengagement therewith by said doors.

L61. In combination, a switch, an enclosure therefor having a pair of doors movable to afford inspection of the interior thereof, means for operating said switch from the exterior of the enclosure, mechanism between said doors and switch operating means for preventing the opening of the doors while the switch is closed, said mechanism having an element adapted to obstruct the movement of said switch, the position of said element being controlled by the position of said doors, the closing of said doors removing said element asl an obstacle to the movement of said switch.

62. In combination, a switch, an enclosure therefor having a plurality of doors movable to aord inspection of the interior thereof, means for operating said switch from the `exterior of the enclosure, mechanism .between said doors and said switch operating means for preventing the closing of the switch while the doors are open, said mechanism having an element serving as an obstacle to the closing of said switch, said element being removed to allow free movement of said switch as said doors are closed.

63'. In combination, a switch, an enclosure therefor having a plurality of doors movable to afford inspection of the interior thereof, means for operating said switch from the exterior of the enclosure, mechanism between said doors and said switch switch from movement, the engagement of said doors with said spring pressed member releasing said switch lock to permit closing of the switch.

64. In combination, a switch, an enclosure therefor having a plurality of doors movable to afford individual inspection of two portions of the interior of the enclosure, means for operating said switch from the exterior of the enclosure, interlocking mechanism between said doors and said switch operating means, said mechanism having, a member' moving parallel to the doorl openings and adapted normally to serve as a latch to hold the doors closed while the switch is -open but as a lock to prevent the opening of the doors while the switch is closed.

65. In combination, a switch, an enclosure therefor having a plurality of doors movable to afford inspection of the interior of the enclosure, means for operating said switch from the exterior of the enclosure, interlocking mechanism between said doors and said switch operating means for prohibiting the closing of the switch until the doors are closed, said mechanism having a bodily movable member adapted to be engaged by the doors when the latter are closed whereby the switch is released and .serving as a barrier to the closing of the switch, said barrier member adapted to be liipped out of position for releasing said. switch and permitting it to close.

67. In combination, a switch, an enclosure for said switch having doors movable to afford inspection of the interior thereof, means for operating said switch from the exterior of the enclosure, interlocking mec-hanism between said doors and said switch operating means for prohibiting the closing of the switch until the doors are closed, said mechanism having a member adapted to be engaged by all of said doors when the latter are closed whereby the switch is released and permitted to close. y

68. In combination, a switch, an enclosure,"

spection of the interior of the enclosure,

l means for operating said switch, interlocking' mechanism between said doors andV said switch operating means for prohibiting the closing of the switch until the doors are closed, said mechanism provided with a pivotally mounted barrier ada ted to lie in thepath of the switch, and means or flipping said barrier out of the path of the switch as the doors are closed.

69. In combination, a switch, an enclosure therefor having a plurality of doors movable to aord inspection of the interior of the enclosure, means for operating said switch from the exterior of the enclosure, interlocking mechanism betweenv ,said doors and said switch operating means for prohibiting the closing of t-he switch until the doors are closed, said mechanism having a switch lock adapted to hold the switch in open position, the closing movement of said doors releasing said switch lock to permit closing of said' switch, and disabling `means for releasing said switch lock to permit closing of the switch while the doors remain open.'

- 70. In combination. a switch, an enclosure for said switch having doors movable to afford inspection of the `interior of the enclosure, means for operating said switch from the exterior of said enclosure, interlocking mechanism between said doors and said switch operating means for prohibiting the closing of the switch until the doorsv are closed, a switch lock provided as part of said mechanism for preventing the movement of the switch., said switch lock being released by the closing movement of said doors, said closing movement being transmitted through another member of said mechanism, and a disabling device for directly engaging said switch lock for releasing vsaid switch while the doors remain open.

71. In combination, a switch, an enclosure therefor having a plurality of doors movable to aii'ord inspection of the interior of the enclosure, means for operating said switch, interlocking mechanism between said doors and said switch operating means for prohibiting the opening of the doors until ,the switch is open, and means for disabling said mechanism to permit said doors to open while the switch is closed, the opening of said doors, while said mechanism is disabled resetting the interlock to prevent the return of said switch to closed position if then opened.

72. In combination, a switch` an enclosure therefor having a plurality of doors movable to afford inspection of thel interi or'of the enclosure, means for operating said switch, interlocking mechanism between said doors and said switch operating means for prohibiting the opening of the doors while the switch is closed, means for disabling said mechanism to permit said doors to open while the switch is closed, the opening of said doors while said mechanism is disabled resetting the interlock to prevent the return of the switch to closed position if then opened, and means for releaslng the switch to permit its return again to closed position while the doors are open.

73. In combination, a switch, an enclosure therefor having a plurality of doors for aiording inspection of the mterior thereof, an interlock between said switch and said doors for `prohibiting the closing of the switch until the doors are closed and the opening of the doors until the switch is open, said interlock including a lock bar common to said doors for holding the doors closed, said lock bar being inaccessible for manual operation and adapted for movement only by engaging portions of said interlock, said engaglng portions moving said bar as the switch is opened to withdraw the bar from engagement with the doors.

74. In combination, a switch, an enclosure therefor having a plurality of doors for affording inspection of the interior thereof, an interlock between said switch and said doors for prohibiting the closing of theswitch until the doors areclosed and the opening of the doors untilthe switch is closed, said interlock including a common lock bar for locking said doors closed while the interlock is effective and for holding said doors latched but capable of being opened while the interlock is inetfective, said lock bar being movable out of locking or holding relation with said doors by engaging portions of said interlock, and disabling means for moving said bar out of locking relation with said doors while said interlock is effective.

75. In combination, a switch, an enclosure therefor, said enclosure provided with a pair of doors affording inspection of different parts of the interior of the enclosure, means for operating said switch, an interlock between said switch and doors for preventing the closing of the switch until the doors are closed and the opening of the doors until the switch4 is opened, said interlock having in` terconnecting means between said doors so that the doors are simultaneously released and locked, and means included'in said interlock adapted to be engaged by said doors upon closing to release said switch from open position.

7 6. In combination, a. switch having fuses associated therewith, an enclosure therefor, doors on said enclosure movable to aii'ord inspection of both said switch and said fuses, a door on said enclosure movable to afford displacement of said fusesthel area covered by said fuse displacement door including the area covered by said fuse inspection door.

77. In combination, a switch having fuses associated therewith, an enclosure therefor, doors on said enclosure affording access to two compartments provided within the enclosure, one of said compartments containing said switch andthe other compartment containing said fuses, the door for said fuse compartment having an opening provided therein, a third door over said opening, and means for preventing displacement of said fuses when said third door is open and the fuse compartment door is closed.

78. In an enclosed switch having fuses in circuit therewith, a compartment for said switch and a compartment for said fuses, a movable door for said switch compartment p and a pair of movable doors for said fuse compartment, one of said latter doors affording limited access to said fuse compartment and the other door affording acces-s to the entire compartment` and both of said latter doors being operable independently of said switch compartment door.

79. In an enclosed switch having fuses in circuit therewith, a compartment for said switch and a compartment for said fuses, a movable door for said switch compartment and a pair of movable doors for said fuse compartm'ent, one of said latter doors affording limited access to said fuse compartment and the other door affording access to the entire compartment, the first of said latter doors being carried by the second whereby movement of the second will carry the first therewith, and both of said latter doors being operable independently of said switch comparment door.

80. In an enclosed switch having fuses in circuit therewith, two doors substantially of the same size for affording access to said switch and fuses, and athird door of smaller size and included within one of said doors for affording inspection only of said fuses.

81. In an enclosed switch having fuses in circuit therewith, the combiation with two doors for affording access to said switch and fuses, of a third door of smaller size and included within one of said doors for affording inspection only of said fuses, and means carried by said fuse access door for preventing the displacement of said fuses when said third door is open.

82. In an enclosed switch having fuses in circuit therewith, the combination with two doors for affording access to said switch and fuses, of a third door included within one of said doors for affording inspection of said fuses, and insulation barriers carried by said one door for lying over and preventing the displacement of said fuses.

83. In an enclosed switch having fuses in circuit therewith, the combination with a casing having substantially one side thereof covered entirely by two doors, of a third door carried byone of said doors, and fuse termi nal engaging members on the linner side of said one door for preventing Athe displacement of said fuse while the door is closed.

84. vIn an enclosed switch having fuses in circuit therewith and an enclosure provided with doors movable to afford access to the interior thereof, certain of said doors being interlocked with said switch for prohibiting the opening of the same until the switch is open7 another' door being also interlocked with said switch for affording access to the intermediate portions of said fuses but preventing the removal of the fuses, and means for rendering said interlock ineffective to permit said last door to open while the switch is closed.

85. In an enclosed switch having fuses in f circuit therewith, the combination with a casing having two doors provided thereon for affording access to said switch and fuses, of a third door embodied in the door for affording access to said fuses, and means for prohibiting the removal of said fuses while said third door is open.

86. In an enclosed switch having fuses in circuit therewith, the combination with a casing provided with two doors for affording access to said switch and fuses, of a third door embodied in the door affording access to said fuses, latch mechanism normally holding said third door closed, and'means lying over the terminals of said fuses for prohibiting the removal of the 'fuses while said third door is open.

87. In an enclosed switch having a casing provided with a door for affording access to said switch, the combination with a fuse in circuit with said switch and a second door on said casing for affording access to the fuse, of a third door associated with said second door for permitting inspection of said fuse, and means cooperating with said switch and Said doors whereby the doors can not be opened until the switch is open,'said means prohibiting the'releasing of said second door without releasing said third door.

88. In an enclosed switch having a casing provided with a door for-affordingaccess to said switch, the combination with a fuse in circuit with said switch and a second door for affording access to said fuse, of a third door associated withsaid second door for permitting inspection of said fuse, means on said second door forming a partition within said casing between the space carrying said switch and the space carrying said fuse, said means serving to prevent the removal of said fuse while said first or third doors are open.

89. In an enclosed switch having a casing provided with'a door for affording access to said switch, the combination with a fuse in circuit with said'switch and asecond door for affording access to the fuse, of a third door carried by and embodiedv in said second door for permitting inspection of said fuse,

`terminals for said fuse, and insulation strips arranged to lie over said terminals when said switch is closed to prevent the removal of said fuse.

90. In combination, a switch having fuses associated-therewith, an enclosure for said switch and fuses, a switch inspection door, a fuse `inspection door, a fuse displacement door, an interlock between said doors and said switch for preventing the closing of the switch while the doors are open, a disabling device for permitting said switch to close while said switch inspection and fuse inspection doors are open, said interlock rendering said disabling device ineffective while said fuse displacement door is open. Y

91.v In combination, a switch having fuses associated therewith, an enclosure for said switch and fuses, a switch inspection door, a fuse inspection door, a fuse displacement door, an interlock between said doors and said switch for preventing the closing of the*l switch while the doors are open, a disabling device for rendering said interlock ineiiective to permit said switch to close while said inspection doors are open, said disabling device being carried on the mechanism of said interlock controlling said fuse displacement door whereby said disabling device is rendered ineffective while the fuse displacement door is open.

92. In combination, a switch'having fuses associated therewith, an enclosure for said switch and fuses, a switch inspection door, a fuse inspection door, a fuse displacement door, an interlock between said doors and said switch for preventing the closing Yof the switch while the doors are open, said interlock including a movable bar, said bar upon being retracted'adapted to release said fuse displacement door from locking relation therewith, and a disabling device for rendering said interlock ineffective to permit said switch to close while said inspection doors are open, said disabling device being mounted on said bar to move therewith for rendering the device inoperative whilesaid fuse displacement door is released.

93. In combination, a switch having fuses associated therewith, an enclosure for' said switch andfuses, a switch door, a fuse door, an interlock for prohibiting the closing of said switch while said doors are open, and a disabling device for rendering said interlock ineffective to release said switch and permitl it to close while said switch door is open, said disabling device being rendered inoperative while said fuse door is open.

94. In combination, a switch having fuses associated therewith, an enclosure for said switch and fuses, a switch door, afuse door, an interlock for prohibiting the closing of said switch while said doors are open and the opening of the doors while the switch is closed, a disabling device for releasing said switch door and permitting it to open, a second disabling device for releasing said switch and permitting it to close while said switch door is open,- said second disabling device rendered 'inoperative as soon as said fuse door is opened.

95. In combination, a switch having fuses associated therewith, an enclosure for said switch and fuses, a switch door and a fuse im door, an interlock for prohibiting the closing of said switch while said doors are open, a movable bar included in said interlock serving to lock said'fuse door closed, al pivotally mounted arm movable with said bar, said arm adapted to engage a portion of said interlock for rendering the interlock ineffective and permitting said switch to close while said switch door is open.

96. In combination, a switch having vfuses associated therewith, an enclosure for said switch and fuses, switch and fuse inspection doors movable on said enclosure, a fusey displacement door movable on said enclosure, an interlock between said switch and 'said doors for prohibiting the opening of the doors while the switch is closed and the closing of the switch while the doors are open, said interlock comprising a plurality of lock bars for locking said doors closed and a switch lock adapted to obstruct the movement of the switch when in open position, disabling meansfor releasing said switch lock to permit said switch to close while said inspection doors are open, said switch lock when released by said means serving to predisplacement door.

97. In an enclosed switch having a casing provided with a. plurality of doors for affording displacement access and inspection thereof, the combination of switch operating means and interlocking means, said interlocking means cooperating with said switch operating means and said doors, means for rendering said interlocking means ineffective to permit the closing of said switch while the inspection doors are open, said interlock being ineHective to release the displacement access door after the switch is again opened.

98. In an enclosed switch having fuses associated therewith, a casing having doors afor-ding displacement access and inspection of said switch and fuses, the combination of interlocking means cooperating with said switch and doors, said means comprising a switch lock mounted so as to lie in the y.path of the switch while the switch and d'oors are open, and means operable when the displacement access door is closed for renderin said interlock ineffective whereby said switc may be closed.

99. In combination, a switch and a plurality of fuses associated therewith, an enclosure for said switch and fuses, movable doors on said enclosure, an interlock for preventing said doors to open until said switch is open` and said switch Ato close until said doors are closed,.means for disabling said in- ,vent the movement of one of said bars and thereby prohibit the opening of said fuseloo

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