US2490987A - Circuit breaker and hydraulic actuating means therefor - Google Patents

Description

CIRCUIT BREAKER AND HYDRAULIC ACTUATING MEANS THEREFOR 3 Sheets-Sheet l Filed'Sept. 10, 1943 Z INVENTOR.

fl/m/my MM/Py/w Dec. 13, 1949 VAN Y 2,490,987

- CIRCUIT BREAKER AND HYDRAULIC ACTUATING MEANS THEREFOR Filed Sept. 10, 1943 3 Sheets-Sheet 2 A. VAN RYAN CIRCUIT BREAKER AND HYDRAULIC ACTUATING MEANS THEREFOR Dec. 13, 1949 3 Sheets-Sheet 3 Filed Sept. 10, 1943 1477 Ali).

Patented Dec. 13, 1949 CIRCUIT BREAKER AND HYDRAULIC ACTUATING MEANS THEREFOR Anthony Van Ryan, South Milwaukee, Wis., assignor to Line Material. Company, a corporation of Delaware I Application September 10, 1943, Serial No. 501,739

8 Claims. (Cl. 60-545) This invention relates to circuit breakers.

Various attempts have been made to use circuit breakers in distribution systems where fuses are also used. These attempts have not proven wholly satisfactory for circuit breakers as ordinarily made will not coordinate with the fuses, and in addition to this the circuit breakers as ordinarily made are too expensive as compared with the cost of the fuse devices.

Objects oi this invention are to provide a circuit breaker which has a time current characteristic corresponding to that of the ordinary type of fuse devices used on distribution systems so that the circuit breaker can be installed in such systems and will coordinate properly with the fuses used in other portions of the system, and a further object is to provide a circuit breaker which although having the time current characteristic of fuses nevertheless is economical to construct.

In greater detail, objects of this invention are to provide'a circuit breaker in which it is not necessary to use an insulating housing but in which a metal can or housing which is filled with oil is provided which is completed by an insulating cover or cap, all of the exposed parts of the apparatus being electrically dead at all times except for two terminal members which are carried by the cap and project through the cap, the can being free from any holes or apertures or bushings therethrough and being open only at the top to thereby guard against loss of oil.

Further objects are to provide a circuit breaker in which all parts of the circuit breaker are carried from an insulating cap, the construction being such that the circuit breaker may be lifted from the can if desired for inspection or repair without removing the can from its mounting.

Further objects are to'provide a circuit breaker which though it has the time current characteristics of a fuse device, which characteristics are secured through the use of a condition responsive or overload device provided with time delay means, nevertheless is so made that it has substantially instantaneous response to a severe overload independently of the action of the time delay means.

Further objects are to provide a circuit breaker in which a single magnetic means is employed to normally secure the tripping of the circuit breaker after a predetermined delay, but which is so related to the other portions of the tripping means that this same magnetic means will secure substantially instantaneous tripping of the circuit breaker for heavy overloads.

Further objects are to provide a circuit breaker which has automatic means and manual means either of which is effective to open the circuit breaker with a quick motion, in which the same manual means which is used to open the circuit breaker is also used as a resetting means and is so related to other portions of the circuit breaker that the circuit breaker can operate automatically independently of such manual resetting means, thereby allowing the circuit breaker to open automatically although the manual resetting means may be in operation to reset the circuit breaker and although the manual means may be held in circuit breaker closed position.

Further objects are to provide a circuit breaker in which the automatic action of the circuit breaker does not impart any blow to the manual resetting means so that although the circuit breaker may be suddenly automatically opened while it is being reset, nevertheless no mechanical shock is transmitted to the manual resetting means, thereby protecting the operator in the event the fault still persists while resetting is being attempted.

A further object is to provide a circuit breaker in which no blow is struck the manual means when the manual means is used to open the circuit breaker, thereby protecting the operator against any mechanical shock when he is operating the manual means to open the circuit breaker.

Further objects are to so relate the manual resetting and manual operating means to the remaining portion of the circuit breaker that such manual means will act as an indicating means and indicate whether the circuit breaker is open or closed.

Further objects are to provide a circuit breaker in which an arcing chamber is provided in a very simple manner to predetermine the zone in which the arc is confined, and to so arrange the arcing chamber that it protects other portions of the circuit breaker, the circuit breaker being suspended from the upper insulating cover and being spaced from the bottom of the can, the arcing chamber being freely open at its sides and lower portion and, as stated, spaced above the bottom of the can so that any debris or dislodged particles may drop freely to the bottom of the can out of the zone of either the stationary or movable contacts.

Further objects are to provide a circuit breaker which is so made that it may be adjusted to secure different time current characteristics.

Further objects are to provide a circuit breaker having the above enumerated characteristics in which the arcing chamber, the stationary contacts, and the automatic tripping means are rigid- 1y connected and rigidly brace each other from the cap or cover of the circuit breaker, and in which the automatic tripping means is readily removable or replaceable without disturbing other portions of the circuit breaker, thereby providing a construction in which automatic tripping means may be readily interchanged to thus adapt the circuit breaker to the requirements of different systems in which it may be installed.

Embodiments of the invention are shown in the accompanying drawings, in which:

tops of the bosses I I in accordance with the usual practice. Heavily insulated conductors indicated generally at H and I extend downwardly from Figure 1 is a vertical sectional view through the circuit breaker, such view corresponding to a section on the line I-i of Figure 2.

Figure 2 is a sectional view through the circuit breaker on the line 2-2 of Figure 1.

Figure 3 is a fragmentary sectional view on the line 3-'-3 of Figure 1 with parts broken away.

Figure 4 is a view of the time delay mechanism and the switch mechanism and associated parts removed from the remainder of the circuit breaker and showing an intermediate position that the parts assume when the circuit breaker is tripped by an overload.

Figure 5 is a view corresponding to Figure 4 showing the final position of the parts following tripping on overload.

Figure 6 is a fragmentary view showing a por-.

tion of a further form of tripping means.

The circuit breaker is primarily intended for high tension circuits and is adapted to be supported from a pole or cross-arm or other suitable support.

The circuit breaker comprises a cap or cover portion I formed of insulating-material. All active portions of the circuit breaker are suspended or carried from or by this cap. The cap I serves as a cover for the metal tank 2 which contains oil and may be filled to approximately the level indicated by the reference character 3. The metal tank 2 has no openings through its bottom or sides through which oil might leak and is open only at its upper portion and is preferably provided with a beaded upper edge I which tightly bears against a ring like gasket 5 to thus securely seal the tank at its upper end.

A plurality of bolts 6 having threaded upper ends are provided and extend upwardly through apertures in the cap or cover member I as shown in Figure 1 and are provided with wing nuts 1 adapted to be clamped against upstanding bosses 8 formed integrally with the cap or cover member i. Preferably the wing nuts are provided with downwardly flanged lower portions as indicated at 9 to overhang the upper ends of the bosses 8. The tank is provided with an integral or unitary, outwardly extending bracket in which may be secured to any suitable support, such as a. pole or cross-arm.

From the description thus far given it is apparent that the cover or cap I may be removed from the tank when the wing nuts 1 are removed and the circuit breaker may be bodily lifted from the tank without requiring any draining of the oil from the tank. It may thus be inspected or repaired and may be replaced and the wing nuts again tightened.

The insulating cap or cover member I is provided with a pair of integral upstanding hollow bosses l l which support the high tension terminal members l2. These high tension terminal members are provided with downwardly flanged skirt like portions l3 which overhang the upper portion of the bosses ll, suitable gaskets being provided between the terminal members and the the terminal members.

An arcing chamber is provided and is formed of insulating side members in the form of elongated fiat plates l6 and a transverse upper portion I! preferably formed integral with the side members l5. Stationary contacts l8 are mounted within the arcing chamber adjacent opposite ends thereof and are clamped in place by means of nuts I! carried by threaded studs 20 integral with posts or spacers 2! whose upper ends are secured as shown in Figure 2 within downwardly extending hollow bosses 22 formed integrally with the cover or cap I, the upper ends of the posts or spacers 2| being provided with polygonal-shaped spaced flanges embedded in a low melting point metal which fills the hollow bosses 22 and secures such posts 2| rigidly thereto.

If desired, the inner cavity formed in the bosses 22 may be left rough or sanded in accordance with the usual practice.

The movable contacts are indicated by the reference character 23 and are secured to channelshaped members 24 pivoted on pins 25 carried by the side walls l6 of the arcing chamber. The channel like members 24 are provided with elongated overlapping portions on opposite sides thereof which are equipped with slots 26 within which a pin 21 carried by a rectangularly shaped insulating slide bar 23 is adapted to'operate. It is apparent that when the slide bar 28 is forced downwardly in a manner hereinafter to appear, the movable contacts 23 engage the stationary contacts it. The movable contacts are joined by means of a flexible connector 29. It is apparent alsothat when the slide bar or reciprocating bar 25 is .moved upwardly, the movable contacts 23 will be rocked downwardly away from the stationary contacts l8 until they are arrested by engaging insulating spacer sleeves 30 supported by pins 3! carried by the side walls is of the arcing chamber. The slide bar 28, as will be seen most clearly from Figure 2, is guided by means of a channelshaped guide plate 32 mounted between the side walls is of the arcing chamber and carried thereby.

It is preferable to line the interior of the metal tank or can 2 with insulating sheet material such as fiber indicated by the reference character 2'.'

A rock shaft 33 is carriedin bearings 34 and 35 and extends outwardly beyond one side of the upper cap or cover I. The bearings aresuitably grooved and have polygonal flanges as indicated and are secured within suitably apertured portions formed in the cap i by means of low melting point metal. Preferably the inner surfaces of the cavities surrounding the bearings 34 and 35 are sanded or roughened in accordance with the usual practice. The bearing members 34 and 35 are respectively provided with downwardly and laterally extending lugs 36 and 31.

The outer end of the rock shaft is provided with a manipulating member or eyeleted handle 38 which is rigidly secured thereto. The shaft also carries a sleeve 39 which is provided with a flange 40, the sleeve and flange being notched as indicated at ll. The sleeve 39 is rigidly secured to the shaft. A spring 42 loosely surrounds thesleeve 39 and bears at one end against the lug tween the lever means 45 and the slide rod 28 and comprises an upper link 45 formed of insulating material and a lower channel-shaped metal link 48. The upper link 45 is pivoted to the lever,

means 45 at its upper end by means of the pin 41 and is pivoted at its lower end between the side walls of the lower channel-shaped toggle link member 48 by means of the pin 49. This lower link 48 has downwardly extending ends which are pivotally connected to the upper end of the slide rod 28 by means of the transverse pin 50. Tension springs extend between the pin 58 and the ears or lugs 86 and 81, as shown most clearly in Figure 2, and constantly urge the slide rod 28 upwardly. A light spring 52 tends to straighten out the toggle'formed of the links 46 and 48.

It is to be noted from reference to Figure 1 that the insulating link 48 is provided with a laterally extending foot portion 53 for a purpose hereinafter to appear.

The circuit breaker is shown in closed p0sition in Figure l and in such position it is to be noted that the center of the pin 41 lies just to the left of a line Joining the center of the pin 49 with the center of the shaft 33, and it is to be noted further that the pin .48 lies just to. the left of a line joining the center of the pins 41 and 58 so that the two toggle link mechanisms are each just past dead center. The transverse flange of the link 48 bears against the right-hand side of the link 45 as viewed in Figure l and constitutes a stop for the toggle formed of the links 46 and 48. The sleeve 44 is provided with a projecting lug 54, see Figures 1 and 2, which engages the stationary lug 31 and thus constitutes a stop for the toggle formed of the lever means 45 and the link 46.

It is to be noted that the sleeve 44, which is loose on the rock shaft 38, is also provided with a lug 55 which fits within the notch 41. This lug constitutes the operating lug for rotating the sleeve 44 during resetting in a manner hereinafter described.

Condition responsive means such as overload tripping means may be provided for tripping the circuit breaker. This condition responsive means or overload tripping means comprises a solenoid 55 which is wound on an insulating tube 81. Within the tube 51 a magnetic plunger 58 is provided. This plunger has a reduced upper portion or stem 59 and is urged downwardly by a light spring 50. Any suitable stop means, such as the split pin 5!, may be provided for determinin the lowest or normal position of the plunger.

The upper end of the light spring 58 bears against a plunger 82 which has an upwardly projecting pin 88. The pin 58 passes freely through a valve like member 54 which is urged downwardly by a relatively heavier spring 6.5 and normally seats against and closes the upper end of the tube 51. A cap like member guides the upper end of the pin 53 of the plunger 62. The plunger 62, the pin 68, and the valve like closure member 64 are all formed of non-magnetic material. It is preferable to form the member 88 of magnetic material.

A magnetic strap like member 81, which may be formed of several portions if desired, practically surrounds the solenoid, that is to say, it extends on opposite sides and across the upper and lower portions of the solenoid. This strap like metal member 81 constitutes the outer magnetic frame or yoke of the solenoid. It is apertured at its lower portion to allow the tube 51 to project therethrough and is apertured at its upper portion to allow the cap like member 88 to project therethrough.

The solenoid and associated parts are supported from the upper cap I by means of a lug 48,

cemented in a downwardly extending boss 88. The lug 88 is detachably joined to an upstandinglug 18, for example by means of the screw 1|.- The lug 10 is integral with a. non-magnetic arcuate member 12 which is detachably attached to:

the transverse portion of the magnetic yoke 81, as shown in Figure 3. The arcuate member 12 is preferably slotted as indicated at 18 to form a guidefor a cam-shaped tripping lever 14.

A pair of insulating side brackets 15 are carried by the side wall ii of the arc chamber and are detachably secured as by means of screws 16 to the side walls of the yoke 51 of the solenoid, as shown most clearly in Figures 3, 4 and 5. A transverse pin 11 is carried by the brackets 15 and forms a. pivot support for the cam-shaped lever 14, suitable spacer sleeves 18 being provided as shown most clearly in Figure 3. A spring 18 urges the cam like tripping lever 14 in a counterclockwise direction. The lever 14, it will be noted from Figure 1, overhangs the pin 53 which is an integral part of.the plunger 82.

-It is preferable to form the lever 14 of nonmagnetic material. The lever 14 has a cam surface 14 which is in close proximity to the foot 58 of the lever 48 during closing motion as well as in final closed position of the circuit breaker, so as to allow the circuit breaker to open in a trip free manner even during closing motion if an overload exists;

The operation of-the apparatus is as follows: Assuming that the circuit breaker is closed and the parts are inthe position shown in Figure 1, when an overload of reasonable magnitude occurs, the plunger 58 starts upwardly within the tube 51, its upward motion being retarded by the oil within the tube, the automatic tripping means being submerged-below the oil levelwithin the tank 2. This construction, therefore, provides a time delay means.

The magnetic plunger 58 will travel upwardly, the oil passing between the outer face of the plunger and the inner surface of the tube-51. As the plunger 58 ascends, a stronger and stronger pull will be exerted on the plunger as it enters more fully into the solenoid 56 and consequently thepressure .oi the oil beneath the plunger 82 will gradually increase. There is a slight leak of oil around the plunger or piston 82 so that the oil abovelthe plunger and below the valve like member 84 is at substantially the same pressure and consequently the plunger 62 does not move upwardly. However, as the pressure in the oil above the magnetic plunger 58 increases, it will arrive at a point where it overcomes the spring 55 and lifts the valve like member 84, thus suddenly relieving the oil pressure above the plunger 82. The plunger 52 will suddenly rise upwardly and will rock the trip lever 14 in a clockwise direction, thus tripping the toggle formed of the links a and 48, the springs 5| causing a quick upward the stationary contacts 18. The circuit is, therelore, ruptured below the oil level and within the arc chamber.

After the circuit breaker has been automatically tripped, the handle 38 will occupy the position shown in dot and dash lines in Figure and will thus act as an indicator showing that the circuit breaker has been opened, the handle having moved from its normal approximately horizontal position shown in Figure 1 to its indicating position shown in Fi ure 5. The spring I! urges the handle towards indicating position. It is a light spring and cannot overcome the eilfect of the springs 5! which hold the toggle link mechanism in a slightly over center position when the circuit breaker is in closed position.

During automatic operation of the circuit breaker, the lower toggle mechanism formed of the links 45 and 48 instantaneously occupies or passes through the position shown in Figure 4. However, as the springs 5i cannot exert any zfurther upward pressure on the toggle link mechanism as the motion of the slide bar 28 is arrested by the striking of the movable contacts 23 against the stops or sleeves 30, the spring 52 will straighton out the toggle formed of the links 36 and ll to the position shown in Figure 5,.-the pin l! passing slightly past dead center.

When a very heavy-overload occurs, such as that produced by short-circuit for instance, the magnetic plunger 58 will be immediately drawn upwardly with a very heavy pull and will instantly raise the oil pressure within the tube 51 to a point sumciently high to raise the valve likemember $4 to descend to its normal approximately horizontal position shown in Figure l, the spring 42, see Figure 2, as well as the weight of the handle assisting in this rocking motion. The right-hand shoulder of the notch ii in the flanged sleeve 3! comes to rest against the lug 55 and thus retains the handle in its normal position showing that the circuit breaker is closed.

When it is desired to open the circuit breaker manually, the operator engages the switch stick with the handle 38 and rocks the handle 38 from its normal approximately horizontal position shown in Figure l to its lower-most position shown in Figure 5. During this downward rocking action, the lug 55 and consequentlyv thelever means at is rocked past dead center and the sprin means 5i suddenly causes the lever means Q5 to rock to the position shown in Figure 5 and thus quickly raises the slide 'bar 28, thus opening the circuitbreaker.

It is to be noted that the screw (it which secures the sleeve 3%? to the rock shaft 33, see Figure 2, acts as a stop contacting the stationary lug 38 and limiting the downward motion of the handle, see Figure 5.

lhe width of the notch ll and the lug 55 are so related that when the circuit breaker isbeing manually opened, no blow is imparted to the handle and consequently no mechanical shock is caused the operator. Also it is to be noted that on automatic operation even though the operator and the piston 62 and trip the circuit breaker before the plunger 58 has traveled an aplntciable distance upwardly in the tube 51.

After the circuit breaker has automatically operated due to overload, the plunger 58 travels downwardly under the influence of gravityand under the action of the spri 5].. The piston or plunger 62 is urged downwardly through the action of the spring 19, the force of the sprint: 19 being transmittemthrough the lever it and the stem 63 to the piston 62. In the event the valve like member 54 should close prior to the downward travel of the piston 62, there is enough leak of oil around the piston 62 to replace any oil that may be needed above such piston while the piston is reassuming its normal position.

When it is desired to reset the circuit breaker;

may be moving the handle towards resetting positlon, nevertheless no mechanical shock is transmitted to the handle and consequently the operator is protected against mechanical shock both during automatic action in the event that he is resetting the circuit breaker and during manual operation. Further than this, it is to be noted that although the handle may be held in circuit breaker closed position, or even in its extreme or uppermost position, nevertheless automatic operthe operator engages the handle 38 preferably with a switch stick and'pushes directly upwardly on the switch stick and rocks thehandle-from its dot and dash line position shown in Figure 5 to its uppermost position shown in dot and dash lines in Figure 1. The rocking of the handle rocks the rock shaft 33' and consequently rocks the sleeve 39 which is rigid with the handle and rock shaft. The face 01 the notch ll in the flanged sleeve 39 to the left of the lug 55 engages the lug 55 and consequently rocks the sleeve and the lever means back to the position shown in Figure 1, it being noted that the lower toggle means consisting of the links 46 and it, see Figure 5, for instance, has the center of the pivot 49 slightly to the left of a line joining the pivot points 41 and 50 and consequently the lower tog gle acts as a rigid member. When the lever 45 has been rocked to its final position as shown in Figure 1, it will be seen that the pivot pin E1 is slightly past dead center and thus the upper togale formed of the link it and the lever means 45 is locked. It is to be noted that the movable contacts 23 are resilient and allow a certain amount 9: yield. The operator then allows the handle 38 ation of the circuit breaker can take place it the fault still persists as the lower toggle link mechanism formed of the links 86 and 88 is broken by the automatic overload tripping means.

The rate at which the plunger 58 will be drawn upwardly into the solenoid 56 for anygiven current value is determined by the viscosity of the oil and the relative values of the internal diameter of the tube 5? and the external diameter of the plunger 58. which the plunger 58 will start upwardly is determined by the number of ampere turns in the coil 56 and also by the lowermost or initial position of the plunger 58. A certain amount of adjust-' ment' may be secured by means of the construction shown in Figure 6 and hereinafter described, which adjustment determines the initial positionof the plunger and thereby determines the value oi the current circulating in the winding which will cause the plunger to start moving upwardly wardly extending lead I4 by means of the detachable connector 8i, see Figure l. The other lead 82 of the solenoid is provided with a terminal member 83, see Figures 2 and 3, which is con- The value of the current at nected to one of the stationary contacts l8, the

7 other stationary contact It being connected to the lead l5.

In the construction shown in Figure 6 the solenoid is indicated by the reference character 84. It is wound around an insulating tube 85 within which a magnetic plunger 86 is slidably positioned. The solenoid is provided with the outer against a piston 88. The piston 88 is urged downwardly by means of a relatively heavier spring 80. It is provided with an upwardly projecting stem 91 or pin which is guided in a cap like member 92. The pin, 9| is adapted to operate the trip lever 14 in identically the same manner as the pin 68 of the previously described form of the invention. It is to be noted that the piston 89 and its integral pin 9| are formed of non-magnetic material. It is preferable to form the member 92 of magnetic material.

It is preferable in both forms of the invention to provide a transverse stop pin 93 to limit the downward motion of the plunger 62 of the first form of the invention and 88 of the second form of the invention. In the second form of the invention shown in Figure 6, the lower end of the tube 85 is provided with a spider like bracket 8| through which is threaded an adjusting screw 95 locked in place by means of a lock nut 96. This adjusting screw determines the lowest position of the plunger 86. Obviously in the first form of the invention a similar adjusting screw may be employed.

The operation of the apparatus shown in Figure 6 is as follows: When the plunger 86 is drawn upwardly by a moderate overload, it places the oil beneath the plunger 85 under pressure and as the plunger travels upwardly, the pull on the plunger increases and consequently the oil pressure beneath the piston 89 gradually increases. When this pressure increases to a point sufficient to overcome the spring 90, the plunger 89 rises and its pin 9| operates the trip lever ll. Under heavy overload the plunger 86 is drawn upwardly with an extremely heavy pull and the oil pressure, even at the initiation of the stroke of the plunger 86, is substantially instantly raised to a value sufficient to cause the piston 89 to operate the trip lever.

It is to be noted that in both forms of the invention any debris that may be formed as a result of wear'for instance can drop freely from the tube and avoid wedging or sticking of the plunger. may be formed in the arc chamber can drop freely downwardly from the arc chamber.

It is to be noted that in both forms of the inv ntion the combined overload device and time delay means is readily replaced by other over load and time delay means so that the combined overload and time delay means having the particular characteristics required for any given portion of the distribution system may be most easily installed to secure the exact time current characteristics desired.

It is to be noted that in both forms of the invention the magnetic plungers may be removed. In the first form of the invention this is accomplished by removing the split pin BI and in the second form of the invention by removing the In addition to this any debris that 10 spider bracket 88 after removal of the screws 81. In this manner in either form of the invention diil'erent plungers can be substituted to secure different time current characteristics.

It is to be noted that the arc chamber confines the are to a certain predetermined limited zone and that this arc chamber is freely open at its side and bottom, thus insuring free circulation of the oil during arcing.

It is to be noted that in both forms of the invention the reduced end of the magnetic plunger can contact with the hydraulically moved plunger or piston in the event the hydraulically moved plunger should stick and thus a very positive tripis insured even under these conditions.

On the other hand if desired it is within the province of this invention to so design the tripping means as to have the reduced end of the magnetic plunger of either form of the invention engage the lower face of the hydraulically moved plunger in the normal operation of the apparatus, though this is not the preferred mode of operation. The preferred mode of operation as hereinabove described for both forms of the in.- vention is to have the hydraulically moved plunger actually operated by hydraulic means interposed between the magnetically moved plunger and the first mentioned plunger.

Further it will be seen that it is a very simple matter to remove the wing nuts I and thereafter lift the circuit breaker bodily from the can 2 for inspection or repair without removing the can from the pole or cross-arm or other support and without removing the oil from the can.

It will be seen also that the condition of the circuit breaker can be readily ascertained by a lineman by noting the position of the handle and if the circuit breaker has been automatically,

tripped, it may be most easily reset.

It will be seen further that by proper selection of the number of turns, the position of the magnetic plunger and the relative diameter of the plunger and the internal diameter of the tube through which it slides, any desired time current characteristic may be secured and thus the circuit breaker may be coordinated with any desired fuse device.

It will be seen that a single magnetic member. such as the magnetic plunger, is employed to both produce the normally delayed action for an overload of resonable magntlude and toalso produce the substantially instantaneous action of a violent overload.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illutratlve rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. Delayed action tripping means for a circuit breaker comprising a tube adapted to be submerged in a liquid, a solenoid surrounding said tube, a piston located in said tube adjacent one end of said tube, closure means for said end of said tube, a spring yieldingly holding said closure means in tube closing position, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid, said plunger being delayed in its motion by the liquid in said tube, said plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said closure means being unseated and said piston being moved outwardly when the pressure exceeds a predetermined value.

2. Delayed action tripping means ior a circuit breaker comprising a tube open at both ends and adapted to be submerged in a liquid, a solenoid surrounding said tube, a non-magnetic piston located in said tube adjacent one end of said tube, non-magnetic closure means for said end of said tube, a spring yieldingly holding said closure means in tube closing position, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid, said plunger being delayed in its motion by the liquid Y in said tube, said plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said closure means being unseated and said piston being moved outwardly when the pressure exceeds a predetermined value. 3. Delayed action tripping means for a circuit breaker comprising a tube open at both ends and adapted to be submerged in a liquid, a solenoid surrounding said tube, a piston located in said tube adjacent one end of said tube, said piston having a power transmitting portion, closure means for the end of said tube adjacent said piston, a spring yieldingly holding said closure means in tube closing position, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid, said magnetic plunger being delayed in its motion by the liquid in said tube, said magnetic plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said closure means being unseated and said piston being moved outwardly when the pressure exceeds a predetermined value.

4. Delayed action tripping means for a circuit breaker comprising a tube open at both ends and adapted to be submerged in a liquid, a solenoid surrounding said tube, a piston located in said tube adjacent one end of said tube, closure means for the end of said tube adjacent said piston, a spring yieldingly holding said closure means in tube closing position, said piston having a power transmitting means passing outwardly through said closure means, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid, said magnetic plunger being delayed in its motion by the liquid in said tube, said magnetic plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said closure means being unseated and said piston being moved outwardly when the pressure exceeds a predetermined value.

5. Delayed action tripping means for a circuit breaker comprising a tube adapted to be submerged in a liquid, a solenoid surrounding said tube, a piston located in said tube, said piston having a power transmitting portion, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid, said magnetic plunger and said tube coacting whereby said magnetic plunger is delayed in its motion when moving into said solenoid by the liquid in said tube, said plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said piston being moved outwardly when said pressure exceeds a mode I termined value.

6. Delayed action tripping means for a circuit 12 a breaker comprising a tube open at both ends adapted to be submerged in a liquid, a solenoid surrounding said tube, a non-magnetic piston located in said tube, said piston having a power transmitting position, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid, said magnetic plunger and said tube coacting whereby said magnetic plunger in delayed in its motion when moving into said solenoid by the liquid in said tube, said plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said piston being moved outwardly wlien said pressure exceeds a predetermined va ue.

7. Delayed action tripping means for a circuit breaker comprising a tube open at both ends adapted to be submerged in a liquid, a solenoid surrounding said tube, a non-magnetic piston located in said tube, said piston having a power transmitting portion, spring means acting directly on said piston and urging said piston inwardly of said tube, and a magnetic plunger in said tube adapted to be drawn into said solenoid when current beyond a predetermined value passes through said solenoid; said magnetic plunger being delayed in its motion-\when moving into said solenoid by ,the liquid in said tube, said plunger when moving into said solenoid placing the liquid in said tube under an increasing pressure, said piston being moved outwardly when said pressure exceeds a predetermined value.

8. Tripping means for a circuit breaker, said tripping means comprising a fluid filled tube, a piston within said tube arranged to operate as the tripping agency when said piston moves towards one end of said tube when the fluid pressure within said tube exceeds a predetermined pressure, a solenoid surrounding said tube, and a magnetic plunger within said tube adapted to be drawn into said solenoid when current passing through said solenoid exceeds a predetermined value; said magnetic plunger placing said fluid under an increasing pressure as said plunger moves into said solenoid and being arranged to produce said predetermined pressure when said magnetic plunger nears completion of its stroke, said tripping means having provision for the slow escape of fluid trapped in said tube between said magnetic plunger and said piston to delay the motion of said plunger, said plunger being arranged to create sufiicient pressure to move said piston to tripping position at the initiation of motion of said plunger when the current passing through said solenoid exceeds a second prede-- termined value higher than said first mentioned predetermined value.

ANTHONY VAN RYAN.

REFERENCES CITED .The following references are of record in th file of this patent:

UNITED STATES PATENTS

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