US2389856A - Time delay-relay switch - Google Patents
Time delay-relay switch Download PDFInfo
- Publication number
- US2389856A US2389856A US499415A US49941543A US2389856A US 2389856 A US2389856 A US 2389856A US 499415 A US499415 A US 499415A US 49941543 A US49941543 A US 49941543A US 2389856 A US2389856 A US 2389856A
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- Prior art keywords
- piston
- partition
- terminals
- switch
- compartment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H43/00—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed
- H01H43/24—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to a non-rotatable moving part
- H01H43/28—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to a non-rotatable moving part the actuation being produced by a part, the speed of which is controlled by fluid-pressure means, e.g. by piston and cylinder
- H01H43/285—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to a non-rotatable moving part the actuation being produced by a part, the speed of which is controlled by fluid-pressure means, e.g. by piston and cylinder adjusting the time interval by means of an adjustable orifice, e.g. needle valve
Definitions
- 'I'his invention relates to time delay-relay switches and more particularly to such switches that are used for detonating a blasting charge.
- the wires of the detonators and the power 'wires leading to the blast must be individually short circuited to protect the blaster from the hazards produced by stray currents getting into the blast circuit. To do this it is imperative that the time delay-relay switch be placed comparatively close to the blasting charge.
- a further object is to provide a means of varying the time delay interval.
- Another object of the invention is to provide a time delay-relay switch of rugged construction which will protect the blaster from premature explosions due to stray currents.
- Fig. 1 is a longitudinal section of the switch
- Fig. 2 is a. cross sectional view taken on the line II-II of Fig. l;
- Fig. 3 is a cross sectional view taken on the line III-III of Fig. 1.
- the switch has a body member 2 which preferably consists of a short length of strong steel tube 4 threaded on each end for receiving pipe flanges 6 and 8. Attached to these flanges by means of bolts and nuts I'Il are blind pipe flanges I2 and I4. Within the body portion of the switch intermediate the end thereof is a partition I6 secured to the body members by means of machine screws I8. The partition I6 divides the body member into two parts, a fluid cylinder 20 and a switchcompartment 22.
- the blind flange I2 has a hole 24 therein through which a piston rod 26 extends into the cylinder 20.
- a stuffing box 28 prevents lossiof fluid from the cylinder 20.
- the piston rod has a handle 30 at its outer end and a reduced portion 32 on its inner end on which is mounted a piston 34.
- a leather cup type washer 36 mounted on the piston 34 prevents flow of fluid past the piston.
- a check valve 38 permits rapid flow of fluid from one sideV of the piston to the other when the piston is moving away from the partition I6 and an adjustable needle valve 40 mounted on the piston 34 permits slow flow of fiuid through the piston.
- a spring 4I surrounds the piston rod 26 between blind flange I2 and piston 34.
- a plurality of fixed electrical contacts are arranged within the switch compartment 22.
- Two L-shaped contacts 42 are fastened to the partition I6 by means of screws 44 and are insulated from the body 2 by means of a cylindrical insulating member 46, a disk'insulator 48, insulating bushings 5 and insulating washers 52.
- a pair of L-shaped electrical contacts 54 are fastened to the pipe 4 by means of screws 56 which extend through the wall of pipe 4, the outer ends of the screws serving as power terminals for the power circuit.
- the contacts 54 and screws 56 are insulated from the body 2 by means of cylindrical insulator 46, disk insulator 48, insulating bushings 58 and insulating washers 69.
- each of the L-shaped contacts 42 Fastened to each of the L-shaped contacts 42 by means of a screw 62 is an electrical contact 64.
- a filler plate 66 is mounted within the pipe 4 adjacent the blind flange I4 and is held in place by means of bolts 68, one of which extends from each of the electrical contacts 64 to the outside of the body member 2 Where nut l0 holds it in place.
- the bolt 68 and electrical contacts 64 are insulated from the body member by means of cylindrical insulator 46, disk insulator l2, insulating bushing I4 and insulating washer 16.
- the outer ends of bolts 68 serve as terminals in the blasting circuit.
- An electrical contact 'I8 is attached to each of the L-shaped contacts 54 by means of a screw 80, the contacts being insulated from the body member 2 by means of cylindrical insulator 46 and disk insulator 12.
- a switch push rod 84 extends through a hole 82 in the partition I6.
- a steel supporting member 86 having a pair of lugs 8l thereon which cooperate with guides B9 to prevent its turning.
- Mounted on the member 86 adjacent the partition I6 are a pair of flat elliptical spring brass electrical contacts 68.
- Another pair of flat elliptical spring brass electrical contacts 90 are mounted on the other side of member 86 at right angles to contacts 88.
- the contacts 88 and 90 are insulated from the member 86 by means of disk insulators 92 and insulating bushings 93. That end of the rod 84 within the switch compartment is reduced in cross section and passes through member 86. A spring 94 surrounds the reduced portion of the rod 84 and abuts against the bottom of a recess 86 in the filler member 66. A plurality of switch. A locking pin
- 08 is then inserted in a i hole
- the fluid in the cylinder 2E!A is preferably oil which will pass through the openingl 82 in partition I6 into switch compartment 22.
- the oil in the switch compartment prevents condensation of moisture therein to remove the ypossibility of the moisture short circuiting the contacts and alsoprevents arcing within lthe, switch.
- a time delay switch comprising a body, a partition in said body dividing it into a fluid cyl,- inder and a switch compartment, a pair of input terminals connected to said body within said compartment, a pair of output Iterminals connected to said body within said compartment, a longitudinally movable member mounted in said mpartmeht having 011e end. thereof extending.
- a time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connectedv to said body within said compartment, a pair of output terminals connectedto said body within said compartment, a longitudinally movable member mounted in said compartment having one end thereof extending through said partition, a plurality ⁇ of electrical contacts mountedv on said movable member, one
- a time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connected to. said body within. said compartment, a ⁇ pair of output terminals connected to said body within said compartment, al longitudinally movable member Imounted in. said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts ⁇ mounted on each side of said movable member, the electrical contacts adjacent said-partition normally connecting.
- a time delay switch comprising a body, a partition, in said body dividing it into a fluidcylinder and a switchco'mpartment, a pair of input terminals connectedtosaid body Within said compartment, a pair o-f output terminalsY connected.
- va llongie tudinally movable member mountedin said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts mounted on each side of said movable member, the electrical contacts adjacent said partition normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, resilient means tending to force said piston toward said partition, a needle valve on said piston permitting flow of fluid therethrough, means for varying the rate of flow through said piston, means for permitting flow of fluid through said piston during movement of said piston away from said partition, means for holding said resilient means in compression, means for releasing said holding means whereby the resilient means forces the piston toward said partition to move said movable member to disconnect the connected pair of terminals and to connect the input terminals to the output terminals by means of the electrical contacts remote from said partition.
- a time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connected to said body Within said compartment, a pair of output terminals connected to said body Within said compartment, a longitudinally movable member mounted in said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts mounted on each side of said movable member, the electrical contacts adjacent said partition normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, a, spring surrounding said piston rod tending to force said .piston toward said partition, a needle valve on said piston permitting flow of fluid through said piston, said piston rod extending through said piston, means on said piston rod for holding said spring in compression, said spring upon release of said holding means forcing the piston toward the partition so that after an interval of time the extension of said piston rod will contact the end of said
- a time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connected to said body within said compartment, a pair of output terminals connected to said body within said compartment, a longitudinally movable member mounted in said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts mounted on each side of said movable member, the electrical contacts adjacent said partition normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, a spring surrounding said piston rod tending to force said piston toward said partition, a needle valve on said piston permitting ow of fiuid through said piston, a check valve, on said piston permitting flow of fluid through said piston during movement of said piston away fromsaid partition, said piston rod extending through said piston, means on said piston rod for holding said spring in compression, said spring upon release of said holding means
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- Arc-Extinguishing Devices That Are Switches (AREA)
Description
2 Sheets-Sheet l Hl TTORNEY.
/Wff "ff /0 M u A M i Filed Aug. 20, 1943 y1 96 if W JONES TIME DELAY-RELAY SWITCH Nov. 27, 1945.
Nov. 27, 1945; w.- JONES TIME DELAY-RELAY SWITCH 2 Sheets-Sheet 2 Filed Aug. 20, 1943 INVENTOR' BYE4 ls ATTORNEY.
Patented Nov. 27, 1945 TIME DELAY-RELAY S'WITCH William Jones, Ely, Minn., assignor to Oliver Iron Mining Company, a corporation of MinnesotaI Application August 20, 1943, Serial N o. 499,415
(Cl. 20o-34) 6 Claims.
'I'his invention relates to time delay-relay switches and more particularly to such switches that are used for detonating a blasting charge. In setting off a blasting charge, while loading and preparing the blast, the wires of the detonators and the power 'wires leading to the blast must be individually short circuited to protect the blaster from the hazards produced by stray currents getting into the blast circuit. To do this it is imperative that the time delay-relay switch be placed comparatively close to the blasting charge.
It is an object of this invention to provide a time delay-relay switch which will keep the blast side of the circuit open from the power side and which will also operate to maintain a short circuit of both the power side and the blast side of the circuit, thus preventing a premature explosion.
A further object is to provide a means of varying the time delay interval.
Another object of the invention is to provide a time delay-relay switch of rugged construction which will protect the blaster from premature explosions due to stray currents.
These and other objects will be more apparent after referring to the following specification and attached drawings, in which;
Fig. 1 is a longitudinal section of the switch;
Fig. 2 is a. cross sectional view taken on the line II-II of Fig. l; and
Fig. 3 is a cross sectional view taken on the line III-III of Fig. 1.
Referring more particularly to the drawings the switch has a body member 2 which preferably consists of a short length of strong steel tube 4 threaded on each end for receiving pipe flanges 6 and 8. Attached to these flanges by means of bolts and nuts I'Il are blind pipe flanges I2 and I4. Within the body portion of the switch intermediate the end thereof is a partition I6 secured to the body members by means of machine screws I8. The partition I6 divides the body member into two parts, a fluid cylinder 20 and a switchcompartment 22.
The blind flange I2 has a hole 24 therein through which a piston rod 26 extends into the cylinder 20. A stuffing box 28 prevents lossiof fluid from the cylinder 20. The piston rod has a handle 30 at its outer end and a reduced portion 32 on its inner end on which is mounted a piston 34. A leather cup type washer 36 mounted on the piston 34 prevents flow of fluid past the piston. A check valve 38 permits rapid flow of fluid from one sideV of the piston to the other when the piston is moving away from the partition I6 and an adjustable needle valve 40 mounted on the piston 34 permits slow flow of fiuid through the piston. A spring 4I surrounds the piston rod 26 between blind flange I2 and piston 34.
A plurality of fixed electrical contacts are arranged within the switch compartment 22. Two L-shaped contacts 42 are fastened to the partition I6 by means of screws 44 and are insulated from the body 2 by means of a cylindrical insulating member 46, a disk'insulator 48, insulating bushings 5 and insulating washers 52. A pair of L-shaped electrical contacts 54 are fastened to the pipe 4 by means of screws 56 which extend through the wall of pipe 4, the outer ends of the screws serving as power terminals for the power circuit. The contacts 54 and screws 56 are insulated from the body 2 by means of cylindrical insulator 46, disk insulator 48, insulating bushings 58 and insulating washers 69. Fastened to each of the L-shaped contacts 42 by means of a screw 62 is an electrical contact 64. A filler plate 66 is mounted within the pipe 4 adjacent the blind flange I4 and is held in place by means of bolts 68, one of which extends from each of the electrical contacts 64 to the outside of the body member 2 Where nut l0 holds it in place. The bolt 68 and electrical contacts 64 are insulated from the body member by means of cylindrical insulator 46, disk insulator l2, insulating bushing I4 and insulating washer 16. The outer ends of bolts 68 serve as terminals in the blasting circuit. An electrical contact 'I8 is attached to each of the L-shaped contacts 54 by means of a screw 80, the contacts being insulated from the body member 2 by means of cylindrical insulator 46 and disk insulator 12. A switch push rod 84 extends through a hole 82 in the partition I6. Mounted on this rod within the switch compartment is a steel supporting member 86 having a pair of lugs 8l thereon which cooperate with guides B9 to prevent its turning. Mounted on the member 86 adjacent the partition I6 are a pair of flat elliptical spring brass electrical contacts 68. Another pair of flat elliptical spring brass electrical contacts 90 are mounted on the other side of member 86 at right angles to contacts 88. The contacts 88 and 90 are insulated from the member 86 by means of disk insulators 92 and insulating bushings 93. That end of the rod 84 within the switch compartment is reduced in cross section and passes through member 86. A spring 94 surrounds the reduced portion of the rod 84 and abuts against the bottom of a recess 86 in the filler member 66. A plurality of switch. A locking pin |08 is then inserted in a i hole |02 in piston rod 2G which hole is immediately above the stuffing box 28 when the spring 4| is fully compressed. This removes thel pressure from the switch push rod 84 and permits spring 94 to push the movable switch contacts 88 and 9i) toward partition I6 until the contacts 38 contact fixed contacts 42 and 54. In this position one contact 88 extends between contacts 5.4 thus short circuiting the input terminals 55 and the other contact 83 extends between contacts 42 whichA are in electrical contact with fixed contacts 64 thus short circuiting the output terminais 68. After the switch is cocked and located in position by means of the pin |80 the power wires are attached to input terminals 56 and a ground wire is run from a hole |04 in one of the bolts |[Iv to a suitable electrical ground thus grounding thebody 2. The miner then charges the blast 'holes and connects his detonator wires to switch terminals 68. After the blast holes are charged vand al1 connections are made to the switch the miner pulls the pin |80 from hole |62 thus permitting spring 4| to be released. This.
spring 4|. moves the push rod 84 and compressesY the spring 94. The movement of push rod 84 carries the contacts 88 out of contact with con" tacts 42V and 54 so that the power and blastingY circuits are no longer short circuited. Continued movement of the rod 84 causes each contact 9i). to contact oney contact 64 and one Contact 18, thus connecting the input terminals 56 to output-J terminals 68 to send current through the blast. The fluid in the cylinder 2E!A is preferably oil which will pass through the openingl 82 in partition I6 into switch compartment 22. The oil in the switch compartment prevents condensation of moisture therein to remove the ypossibility of the moisture short circuiting the contacts and alsoprevents arcing within lthe, switch.
While one embodiment ofk the invention has been, shown anddescribed, it will be apparent that other adaptations and modifications may be made without departing from the scope of the attached claims.
1,.A A time delay switch comprising a body, a partition in said body dividing it into a fluid cyl,- inder and a switch compartment, a pair of input terminals connected to said body within said compartment, a pair of output Iterminals connected to said body within said compartment, a longitudinally movable member mounted in said mpartmeht having 011e end. thereof extending.
through said partition, a plurality of electrical contacts mcunted o n said movable member,v one.
of said contacts normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, resilient means tending to force said piston toward said partition, means for permitting flow of fluid through said piston, means for holding said resilient means in compression, and means for releasing said holding means whereby the resilient means forces the piston toward said partition to move said movable member to disconnect the connected pair of terminals and to.
connect the input terminals to the output terminals.
2A. A time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connectedv to said body within said compartment, a pair of output terminals connectedto said body within said compartment, a longitudinally movable member mounted in said compartment having one end thereof extending through said partition, a plurality` of electrical contacts mountedv on said movable member, one
' of said contacts normally connectingv the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, resilient means tending to force said piston toward said partition, means for permitting iiow of fluid through said piston, means for varying the rate of flow through said piston, means for permitting flow of fluid through said piston during movement of said: piston away from said partition, means for holdingysaid resilient meansV in compression, and means for releasing said holding means whereby .the resilientmeans forces the piston toward said partition to move said movable member to disconnect. the connected pair of' terminals and to. connect theinput terminals to the output terminals..
3. A time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connected to. said body within. said compartment, a` pair of output terminals connected to said body within said compartment, al longitudinally movable member Imounted in. said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts` mounted on each side of said movable member, the electrical contacts adjacent said-partition normally connecting.
-nect the connected pair of terminals and to connect the input terminals to the output terminalsA by means of the electrical contacts remote from said partition.
4. A time delay switch comprising a body, a partition, in said body dividing it into a fluidcylinder and a switchco'mpartment, a pair of input terminals connectedtosaid body Within said compartment, a pair o-f output terminalsY connected.
yto said. bodyV within. saidy compartment, va llongie tudinally movable member mountedin said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts mounted on each side of said movable member, the electrical contacts adjacent said partition normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, resilient means tending to force said piston toward said partition, a needle valve on said piston permitting flow of fluid therethrough, means for varying the rate of flow through said piston, means for permitting flow of fluid through said piston during movement of said piston away from said partition, means for holding said resilient means in compression, means for releasing said holding means whereby the resilient means forces the piston toward said partition to move said movable member to disconnect the connected pair of terminals and to connect the input terminals to the output terminals by means of the electrical contacts remote from said partition.
5. A time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connected to said body Within said compartment, a pair of output terminals connected to said body Within said compartment, a longitudinally movable member mounted in said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts mounted on each side of said movable member, the electrical contacts adjacent said partition normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, a, spring surrounding said piston rod tending to force said .piston toward said partition, a needle valve on said piston permitting flow of fluid through said piston, said piston rod extending through said piston, means on said piston rod for holding said spring in compression, said spring upon release of said holding means forcing the piston toward the partition so that after an interval of time the extension of said piston rod will contact the end of said movable member and move it to disconnect the connected pair of ter- Y minals and to connect the input terminals to the output terminals by means of the electrical contacts remote from said partition.
6. A time delay switch comprising a body, a partition in said body dividing it into a fluid cylinder and a switch compartment, a pair of input terminals connected to said body within said compartment, a pair of output terminals connected to said body within said compartment, a longitudinally movable member mounted in said compartment having one end thereof extending through said partition, a supporting member attached to the other end of said movable member, a plurality of electrical contacts mounted on each side of said movable member, the electrical contacts adjacent said partition normally connecting the terminals of one of said pairs of terminals, a piston rod extending through the end of said body into said cylinder, a piston connected to said piston rod, a spring surrounding said piston rod tending to force said piston toward said partition, a needle valve on said piston permitting ow of fiuid through said piston, a check valve, on said piston permitting flow of fluid through said piston during movement of said piston away fromsaid partition, said piston rod extending through said piston, means on said piston rod for holding said spring in compression, said spring upon release of said holding means forcing the piston toward the partition so that after an interval of time the extension of said piston rod will contact the end of said movable member and move it to disconnect the connected pair of terminals and to connect the input terminals to the output terminals by means of the electrical contacts remote from said partition.
WILLIAM JONES.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US499415A US2389856A (en) | 1943-08-20 | 1943-08-20 | Time delay-relay switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US499415A US2389856A (en) | 1943-08-20 | 1943-08-20 | Time delay-relay switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2389856A true US2389856A (en) | 1945-11-27 |
Family
ID=23985178
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US499415A Expired - Lifetime US2389856A (en) | 1943-08-20 | 1943-08-20 | Time delay-relay switch |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2389856A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2543090A (en) * | 1945-10-08 | 1951-02-27 | Fed Electric Prod Co | Switch |
| US2640295A (en) * | 1947-06-30 | 1953-06-02 | Auler | Timer for model airplanes |
| US3045076A (en) * | 1958-12-29 | 1962-07-17 | Koch & Sons Inc H | Switch actuating device with preadjusted air resistance |
| US3246094A (en) * | 1963-12-13 | 1966-04-12 | Holley Carburetor Co | Delayed return pressure actuated device |
| US3296969A (en) * | 1964-10-14 | 1967-01-10 | Thiokol Chemical Corp | Time delay initiator |
| US3806870A (en) * | 1971-09-17 | 1974-04-23 | E Kalajian | Control responsive caution signal for powered vehicles |
| US4093837A (en) * | 1975-07-31 | 1978-06-06 | Westinghouse Electric Corp. | Oil circuit-breaker pump-assembly with improved shunting contact structure |
| US4490590A (en) * | 1982-02-03 | 1984-12-25 | Mitsubishi Denki Kabushiki Kaisha | Switching system with grounding device |
-
1943
- 1943-08-20 US US499415A patent/US2389856A/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2543090A (en) * | 1945-10-08 | 1951-02-27 | Fed Electric Prod Co | Switch |
| US2640295A (en) * | 1947-06-30 | 1953-06-02 | Auler | Timer for model airplanes |
| US3045076A (en) * | 1958-12-29 | 1962-07-17 | Koch & Sons Inc H | Switch actuating device with preadjusted air resistance |
| US3246094A (en) * | 1963-12-13 | 1966-04-12 | Holley Carburetor Co | Delayed return pressure actuated device |
| US3296969A (en) * | 1964-10-14 | 1967-01-10 | Thiokol Chemical Corp | Time delay initiator |
| US3806870A (en) * | 1971-09-17 | 1974-04-23 | E Kalajian | Control responsive caution signal for powered vehicles |
| US4093837A (en) * | 1975-07-31 | 1978-06-06 | Westinghouse Electric Corp. | Oil circuit-breaker pump-assembly with improved shunting contact structure |
| US4490590A (en) * | 1982-02-03 | 1984-12-25 | Mitsubishi Denki Kabushiki Kaisha | Switching system with grounding device |
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