US2899521A - A- salomone - Google Patents

Description

Aug. 11, 1959 R. A. SALOMONE 2,899,521

FUSE-PULLER SWITCH Filed Oct. 14. 1955 6 Sheets-Sheet 1 INVENTOR RYNOLD A. SALONONE m'd/m ATTORNEY Aug. 11, 1959 R. A. SALOMONE FUSE-FULLER SWITCH Fileci Oct. 14, 1955 6 Sheets-Sheet 2 24 1 In In. u wl I I f I 3 1 I 1 1| l8 I 52 L l ii Z5 "'"1 WW "I INVENTOR RYNOLD A.SALOP'IONE BY Z ATTORNEY 1959 R. A; SALOMONE 2,899,521

' FUSE-FULLER SWITCH Filed Oct. 14, 1955 6 Sheets-Sheet 5 SERIES FEED PARALLEL FEED i I LARGE APPLIANCE INVENTOR RYNOLD A. SALOMONE ATTORNEY 8- 1959 R. 'A. SALOMON; 2,899,521

FUSE-FULLER SWITCH Filed Oct. 14, 1955 6 Sheets-Sheet 4 Q? 36 INVENTOR RYNOLD A. SALOHONE ATTORMEJ Aug. 11, 1959 R. A. SALOMONE FUSE-FULLER SWITCH 6 Sheets-Sheet 5 Filed Oct. 14. 1955 INVENTOR RYNOLD A. SALOMONE ATTORNEY 1959 R. A. SALOMONE 2,899,521

- FUSE-FULLER SWITCH Filed Oct. 14, 1955 6 Sheets-Sheet 6 INVENTOR RYNOLD A. SALOMONE ATTORN EY United States Patent Office 2,899,52i Patented Aug. 11, 1959 FUSE-PULLER SWITCH Rynold A. Salomone, Plainville, Comm, assignor to General Electric Company, a corporation of New York Application October 14, 1955, Serial No. 540,558

2 Claims. (Cl. 200-133) Our invention relates to devices for use in controlling and protecting electric circuits and particularly to devices of the type including plug-in mounted fuse-carrying members, ordinarily used at the point of entrance of electric power lines in residential and other buildings, and referred to in the trade as fuse-puller service entrance switches.

The important general objects of our invention include the provision of a fuse-puller switch which is more compact than prior comparable devices, which is more convenient to install and connect, and which, compared to such prior devices, is of greatly reduced cost.

Another object of our invention is the provision of a fuse-puller device having a main insulating support which requires a minimum amount of insulating material, whereby the cost and weight of such base is reduced.

In accordance with our invention in one form, we provide a fuse-puller switch comprising an elongated generally rectangular insulating support or framework having terminals and plug-fuse-sockets along opposite sides thereof, and two enlarged generally rectangular apertures therethrough, stationary switch contacts within said apertures adjacent the side walls thereof, and insulating guard portions integral with said support shielding said stationary contacts. A generally rectangular insulating cap is provided for closing each aperture, each cap carrying a pair of electric fuses and contact stabs for connecting the fuses to the stationary contacts when the cap is in place. In addition, a pair of offset insulating barriers are carried by the opposed end walls of each aperture, and a correspondingly oifset pair of barriers are carried by each cap so that they overlap each other when the caps are in place to effectively isolate the fuses.

Our invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which Figure 1 is a front elevation view of a fuse-puller switch made in accordance with the invention, the cover of the outer enclosure being omitted and one of the fusecarrying elements or caps being removed;

Figure 2 is a rear elevation view of the fuse-puller device of Figure 1, the outer enclosure and back insulating shield being omitted to more clearly show the parts;

Figure 3 is a schematic representation of the series connections of a typical installation of the fuse puller of Figure .1;

Figure 4 is a perspective exploded view of the parts of a combination terminal and contact element utilized in the fuse-puller switch of Figures 1 and 2, viewed in the same sense as shown in Figure 2;

Figure 5 is a view of a portion of the fuse-puller device of Figure 1 showing particularly a combination terminal and contact element such as illustrated in Figure 4 when in upright mounted position;

Figure 6 is a view on enlarged scale of a portion of the fuse-puller device of Figure 1, and showing a branchcircuit fuse-receiving socket and particularly the pushin wire-connecting terminal means;

Figure 6a is a view similar to Figure 6 but with the terminal strap 34 omitted;

Figure 7 is an exploded perspective View of a portion of the assembly of Figure 6;

Figure 8 is a perspective view of an alternate form of a wire connector and terminal strap for use with the socket of Figure 6.

Figure 9 is a front elevation view of a fuse-puller switch similar to that of Figure 1, but with a terminal arrangement whereby it is adapted for parallel feed connection in a manner to be described, the enclosure and insulating shield being omitted;

Figure 10 is a sectional view taken on the line 10--10 of Figure 9 on a reduced scale and shown in place in an enclosure;

Figure 11 is a rear elevation view of the switch of Figure 9;

Figure 12 is a schematic representation of the parallel connections of a typical installation of the device of Figure 8;

Figure 13 is an end view of a fuse carrier or cap such as used in the puller devices of Figures 1 and 9' with fuses shown in place, and a portion of the co operating stationary contact being shown.

Figure 14 is a bottom plan view of a fuse-carrier such as used in the devices of Figures 1 and 9.

Referring to the drawings, our invention is shown as embodied in a fuse-puller device including a generally rectangular insulating support or framework 10, preferably comprising a single body of molded insulating material, and having two elongated opposed side portions 11 and 12 joined by bridging portions 13, 14 and 15 at the top, center and bottom portions thereof respectively, dividing the space between the sides into two generally rectangular apertures.

The insulating support or framework 10 is mounted within a generally rectangular metallic enclosure or box 16 in a manner to be described, the enclosure 16 being provided with a generally rectangular insulating shield 17 of suitable material such as vulcanized cellulosic fiber mounted on the back wall thereof.

A. Contact and terminal construction The insulating frame 10 is provided with a pair of line terminals 18 each located at one end of the sides 11 and 12 adjacent the top bridging portion 13, a pair of sub-feed terminals '19 located approximately midway of the elongated portions 11 and 12, and with a pair of major branch circuit terminals 20 at the lower ends of the side portions 11 and 12, the side portions 11 and 12 being recessed from the front and back at each of the locations of the terminals 18, 19 and 20 to position and shield the parts.

The major-branch-circuit terminals 20 are identical in construction with line terminals 18. Each of such terrninals includes a contact plate portion 21 (see Figure 4) positioned in a recess and having a bent-over contact portio 22 with endwise projecting portions 22a adapted to be received in closely fitting relation in slots 22b in the sides 11 and 12, In assembly, therefore, this terminal plate 21 is merely pushed into place from the bottom of the framework 10 and is retained therein by the closeness of fit in the conforming recesses 22b, which, for this purpose, are made to taper inwardly toward the closed end. The contact plate 21 also has a projecting tongue portion 23 adapted to be received within a generally tubular clamping member 24 which clamping member may be made of relatively inexpensive material, such as steel. The clamping member or lug 24 is assembled on the tongue 23 before the plate 21'is pushed into place in the support 10'. The plate 21 is adapted to be retained in .place in the support 10 positively by suitable means,

such as by a rivet 25 passing through a hole 26 in the plate 21.

As shown particularly in Figures 2 and 5, when the contact plate 21 is in position, the endwise opening of the lug 24 is available from the end of the support to receive a conductor such as 27 which is adapted to be clamped against the plate 21 by the clamping screw of lug 24. The clamping lug 24 is prevented from sliding oh the portion 23 by the end wall of the base as shown in Figure 5.

It will be observed that with the construction described. when the device is in use and a conductor, such as 27 is clamped in a terminal such as terminal 20, the electrical continuity or eflfectiveness of the electrical connection between such conductor and the remainder of the circuit of the device is not adversely affected by loosening or even complete removal of the fastening means 25.

The major branch-circuit terminals 19 each likewise include a contact plate, 28, comparable to the contact plate 21 of the terminals 18 and 20. The contact plates 28 each have a bent-over contact portion 29 having endwise extensions 29a adapted to be received in closely fitting relation in recesses or slots 2% in the sides 11 and 12 of the support 10. Each plate 28 is adapted to be positively retained in position by means of screws 30 in threaded engagement with tapped holes 31 in the plate 28. The plate 28 has two angularly directed extensions 28a and 28b which, when the plate is assembled in the base, underlie the center of plug-fuse receiving sockets or shells 32. Each of the screws 30 passes through an enlarged hole in the bottom of the sockets 32 and has its head insulated from the socket 32 by means of an insulating washer 33. By means of this construction, the screws 30 serve not only to retain the plate 28 in mounted position on the support 10, but also serve as the center contact for the plug fuse-receiving sockets. It will be understood that when a plug fuse is screwed into the socket 32, it electrically connects the center contact screw 30 with the shell 32.

For the purpose of permitting electrical connection of the wire conductor to the fuse shell 32, we provide a terminal strap 34 which underlies and makes contact with the bottom of the socket shell 32 but is insulated from the screw 30 by enlarged opening 35, The terminal strap 34 preferably has its outer end portion especially adapted to cooperate with portions of the insulating support 10 and with a special spring clip 36, to retain the end of a conductor, such as 37, which is inserted by a simple straight push-in movement. (See Figures 6 and 7). For this purpose the end of the strap 34 is provided with a bent-over portion 38 which forms a generally V-shaped channel 381: therein against which the exposed end of the conductor 37 is adapted to be pressed by the action of the generally L-shaped spring clip 36. The spring clip 36 is adapted to be retained in place in recess 36a on the insulating support 10 by the action of the walls thereof and a generally L-shaped abutment 36b. It will be observed that as the conductor end 37 is forced into the channel 38a it engages and deflects the tip of the spring clip 36 and is trapped between the clip and the portion 38 of strap 34. The spring clip 36 is prevented from rotating in a counterclockwise direction by the engagement thereof with the walls of the recess 36a and by abutment engagement with the abutment 36b. The tip of the steel spring digs into the conductor when the conductor is pulled outwardly, holding it securely in place. In order to make possible the release of a conductor such as 37, we provide an aperture 34a in the strap 34. To release a conductor, it is only necessary to insert an object such as a screwdriver tip in the aperture 34a and deflect the spring away from the terminal portion 38.

Whenit is desired to use a standard screw-type connectlon instead of a push-in type of connector just described, we provide an alternate form of terminal strap,

34', having a tapped hole 39 therein adapted to receive a suitable clamping screw 40. The terminal strap 34 is also preferably provided with elongated indentations 41 for the purpose of improving the holding force exerted on a wire and which is placed under the head of the screw 40 along the indentations 41.

B. Fuse caps and associated base construction Referring now particularly to Figures 10, 13 and 14, each fuse cap 42 comprises an insulating cap portion 43 having mounted on the underside thereof two pairs of generally inverted J-shaped combination contacts and fuse-holder clips 44, which are mounted to the insulating cap 43 by suitable means such as by screws 45. The members 44 include arcuate portions 46 adapted to receive the cylindrical end portioins of ferrules of cartridge type fuses, and also include offset contact portions 47 adapted to make contact with the bent-over contact portions 22 of the combination terminal and contact members 18 and 20 and also with the bent-over contact portions 29 of the combination terminal and contact member 19.

When the fuse cap is in mounted position, such as shown in Figure 10, the combination contact and fuse clips 44 are compressed between the opposed contact portions 29 and such force not only provides the necessary contact force for current conduction at these points of contact, but also exerts a clamping force on the fuses so as to improve the electrical contact and engagement and reduce heating at this important location, Furthermore, an important reduction in width of the frame and corresponding amount of materials required is achieved by utilizing the unitary single strip 44 for both purposes of retaining and contacting the cartridge fuses and for contacting the contact surfaces 29. Thus the required distance between the opposed walls of the side portions 11 and 12 is hardly greater than the necessary clearance distance over the outside of the cartridge fuses in mounted condition.

As indicated especially in Figure 10, the insulating side portions 11 and 12 preferably include wall portions 48 which terminate adjacent the bent-over contact portions 29 and which extend outwardly from the wall portions a small amount whereby as the fuse-carrying cap is inserted the offset contact portions 47 ride along the said wall portions and are compressed inwardly thereby until they travel far enough to pass the termination of the outwardly projecting portions and snap into engagement with the contact surfaces 29. For the purpose of insulating and shielding the contact portions 22 and 29 so as to prevent accidental contact when the fuse-puller caps are removed, insulating barriers 49 are provided, carried by the opposed side portions 11 and 12 and adapted to generally surround the area adjacent the side contact portions and to form a recess or socket into which the contact portions 47 of the members 44 are adapted to pass.

For the purpose of providing electrical clearances between adjacent fuse holders 44 as well as over the surface of the underside of the cap 43, we provide a pair of offset depending insulating barriers 50 and 51 integral with the cap 43. For the purpose of supplementing barriers 50 and 51 to provide adequate through-air clearance between adjacent fuse holders 44, we provide a pair of projecting insulating barriers 52 carried by and integral with the bridging portions 13 and 14 respectively, and a pair of projecting insulating barriers 53 carried by and integral with the bridging portions 14 and 15 respectively. The barriers 50 and 51 are adapted to overlap the barriers 52 and 53 at all times so that when the fuse cap is inserted in an energized position there is no straight line path through air from one of the conductive terminal portions of one fuse to that of another. (See Figures 2 and 11.) The barriers 52 and 53 are positioned on opposite sides' of the center line of the major apertures. The barriers 50' and 51 are also positioned on opposite sides of the center line of the cap '42, the arrangement is also such that when a cap is inserted in an aperture, the barriers 50, 51 extend on opposite sides of the center line of the aperture. This arrangement is clearly illustrated in Figure 2. It will be observed that when the cap 42 is in inserted position, the barriers 52 and 53 substantially increase the throughair clearance between the fuse holders 44 by reason of their overlapping relation to barriers 50, 51 respectively. It will be observed moreover, that such overlapping relation obtains even if the cap is reversed end-for-end in the aperture. The offset arrangement of the barriers 50, 51 and 52, 53 provides overlapping barriers on a reversible fuse cap in the most compact manner possible. Thus it will be observed that the barriers 50, 52 substantially fill the entire space between the adjacent fuse holders 44, as do the barriers 51, 53.

C. Mounting means for support 10 The insulating framework or support 10 is adapted to be retained within the outer enclosure 16 by means of two pairs of retaining hooks 4 and 55 carried by the back wall of the enclosure 16, and adapted to engage integral shelf portions 56 and 57 carried by the opposed side portions 11 and 12 of the support 10. In order to permit passage of the hooks 54 and 55, the insulating shield 17 is provided with correspondingly located apertures 58 and 59. It will be observed that all of the hooks 54 and 55 have their open ends directed in the same direction, so that the insulating support may be mounted within the enclosure 16 by placing it first against the back wall of the enclosure 16 with the shelf portions 56 and 57 adjacent the open ends of the hooks 54 and 55, and then sliding it downwardly so that the shelf portions 56 and 57 become engaged under the hooks 54 and 55. As shown particularly in Figure 10, we also provide the upper bridging portion 13 with a notch or cutaway portion 60 and provide a lug 61 carried by the back wall of the enclosure 16. The lug 61 normally extends at a small angle with respect to the back of the box 16 and the notch 60 is such as to permit the above-mentioned sliding movement of the base 10, so that when said sliding movement is completed and the shelf portions are engaged in the aforesaid hook portion the lug 61 is then adjacent the outer surface of the upper barrier 13 and may be bent outwardly by suitable means, such as by use of a screwdriver.

The lug 61 preferably initially extends upwardly out of the plane of the back wall of the enclosure, as shown in dotted lines in Figure 10, to facilitate its further bending as described. When this is done the insulating support 10 will then be found to be securely locked in position in the enclosure 16. Thus, movement of the support 10 in any direction except in a straight-upward direction (parallel to the back wall) is prevented by the cooperation of the hooks 54 and 55 and the shelves 56 and 57 and the adjacent parts of the insulating support ltl. When the lug 61 is bent upwardly as described such upward movement of the support 10 is also prevented. This construction provides an extremely convenient and rapid method of mounting the support 10 in and/or removing the enclosure 16.

D. Electrical connections In Figure 3 is shown a schematic view of the electrical connections of the fuse-puller switch of Figures 1 and 2. As indicated, in this form, the incoming line conductors are connected directly to the terminals 18. The current path then is: through the combination terminal and contact plate 21 to the contact portions 22, to one end of the main cartridge fuses, to the other end of the main cartridge fuses, to the contact portion 29, to the combination terminal and contact plate 28, to the terminals 19 and also elecrically in parallel to the plug-fuse center contactconsisting'of screws 30. It will be seen that the terminals 20 are connected to fuses which are electrically in series with the aforementioned main fuses and that an electrically conductive path exists from the plate 28 through the contact p'or'tions of the lower fuses to the plate 21 ofth'e terminal 20 and thence to the terminals 20.

"In Figures '9, l0 and 11 is illustrated another embodimerit of our invention especially adapted for installations in which it is desired to have the two fuse-carrying caps electrically in parallel. For such installations, it becomes desirable to use the center terminals 19 as the incoming or line terminals. When so used, such terminals must be able to accommodate conductors of a larger size than can readily be accommodated in the restricted space available between the two plug-fuse sockets of each of the opposed sides 11 and 12. Means is tl'tere-fore provided whereby such terminals may be extended to a location where a ilarger wire connector may be utilized, including insulating means therefor. For this purpose a terminal extension strap 62 is provided, adapted to be retained and connected to the plate 2.8 by means of the screw 19a. A strip of flexible tough insulating material 19b, preferably of vulcanized cellulosic fiber, has its end portion retained under the head of screw 19a and having an intermediate portion wrapped around the connecting lug and retained on the outer portion of the terminal extension strap 62. The insulating means described is claimed in copending application, Serial Number 504,219 filed April 27, 1955, assigned to the same assignee as the present invention.

In Figure 12 we have shown a schematic drawing of the electrical connections of the embodiment of Figures 9, 10 and 11. As shown in this. figure, the incoming line is connected to the mid terminal 19 by means of which it is connected to the combination terminal and contact plate 28 and thence in parallel through the upper and lower cartridge fuses to the upper and lower terminals 18 and 20 respectively. In this form the branch-circuit plug-fuse sockets 32 are insulated from the contact plate 28 by means of enlarged holes 28c in each of the portions 28a and 28b which are adapted to clear the contact screws 30, suitable insulating sleeve being provided. T he ends of the contact screws 30 after passing through the contact plate 28 make threaded engagement with the connecting strap 63 which in turn are connected to the upper terminals 18 by means of screws 64. By this means the branch-circuit plug-fuse sockets, instead of being connected electrically in common to the central terminals 19, are connected electrically in common with the upper terminals 18.

By means of the construction described, we have succeeded in reducing the size and cost of such a fusepuller switch, while at the same time improving its performance and suitability for use. For instance, when compared with the most nearly comparable previous fuse-uller switch, applicants present invention affords a reduction in overall size (displacement) of approximately 25% and a reduction in cost of manufacture of approximately 33 /3%. Applicant has achieved the cost savings referred to by reduction in the total amount of steel, copper and insulating material required, as well as by improved design of the various components permitting easier manufacture and assembly of the parts. At the same time, the present invention provides improved operation and performance and is easier to install and connect than prior designs.

While we have shown and described two preferred embodiments of our invention, it will be understood that many changes, modifications and adaptations may be made in the details thereof without departing from the spirit of our invention, and we therefore intend to cover all such modifications and adaptations as fall Within the true spirit and scope of our invention as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical control device of the fuse-puller type comprising a generally rectangular insulating support, at least one generally rectangular recess in said support generally centrally thereof, said recess having end Walls and side walls, a generally rectangular insulating cap receivable within said aperture so as to substantially close said recess, said insulating cap having means for mounting and electrically connecting electric fuses thereon and having contacts of the stab type for making contact with said contacts on said insulating support, a pair of main switch contacts adjacent each of said side portions of said recess, a pair of relatively short insulating barriers carried by said end walls generally centrally thereof and extending toward the generally central area of said recess parallel to said side walls, said end wall barriers being offset with respect to one another in a direction parallel to said end walls, said removable insulating cap having a pair of depending insulating barriers extending from the surface thereof on which said fuse-mounting means is carried, said fusecap barriers being offset or staggered with respect to one another in a direction parallel to its ends, each of said insulating barriers of said fuse cap being adapted to overlap one of said end wall barriers of said insulating support.

2. An electrical control device of the fuse-puller type comprising a generally rectangular insulating support having at least one generally rectangular aperture centrally thereof extending therethrough from front to back, the back of said aperture being adapted to be closed by a flat planar sheet of insulating material, said aperture being defined by end walls and side walls of said insulating support, a removable generally rectangular insulating fuse carrier adapted to be received within said generally central aperture, said fuse carrier when in mounted position being adapted to support a pair of generally cylindrical cartridge-type fuses within said aperture generally parallel to the said side walls thereof and electrically connected to switch contacts located within said aperture, an end wall insulating barrier carried by each of said end walls between said side portions and extending toward the central portion of said aperture, a pair of insulating barriers depending from the inner surface of said insulating fuse cap between the terminal ends of said cartridge fuses, said fuse-cap insulating barriers being oifset in a direction transverse to the length of said cartridge fuses and offset with re spect to one another to said sides of said aperture, the corresponding barriers of said cap in said support being offset in a relatively opposite direction whereby said end wall insulating barriers overlap said fusecapinsulating barriers a short distance.

References Cited in the file of this patent UNITED STATES PATENTS 1,832,671 Thompson et al. Nov. 17, 1931 1,930,428 Jackson et al. Oct. 10, 1933 1,946,071 Harvey Feb. 6, 1934 2,116,658 Frank May 10, 1938 2,177,518 Douglas Oct. 24, 1939 2,186,813 Adam et al. Jan. 9, 1940 2,193,201 Millermaster Mar. 12, 1940 2,205,322 Thomas et al. June 18, 1940 2,285,928 Jensen June 9, 1942 2,299,153 LaDucer Oct. 20, 1942 2,307,003 Murphy Dec. 29, 1942 2,617,844 Sanda Nov. 11, 1952 2,617,847 Cole Nov. 11, 1952 2,705,785 Benander Apr. 5, 1955 2,738,399 Hammerly Mar. 13, 1956

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