US3761847A

US3761847A - Drive mechanism for electrical switches

Info

Publication number: US3761847A
Application number: US00287285A
Authority: US
Inventors: H Strubin
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Priority date: 1971-09-23
Filing date: 1972-09-08
Publication date: 1973-09-25
Anticipated expiration: 1990-09-25
Also published as: JPS4839973A; FR2153412B1; GB1391919A; IT967686B; CA962727A; DE2151453A1; CH536548A; DE7139087U; FR2153412A1; SE372131B

Abstract

A double-acting drive mechanism for actuating the contacts of an electrical switch between open and closed position includes a cylinder having a double-acting piston therein and a piston rod extending through one end of the cylinder for connection to the contact actuating mechanism of the switch. Each end of the cylinder is closed by a stationary member having a flanged portion provided with one or more circular rows of cartridge chambers serving as a magazine and which communicate with the corresponding end of the cylinder, and a latch-releasable springdriven rotary member carrying a firing pin is mounted on each end closure member for the cylinder for rotation in a step-by-step manner around the row of cartridge chambers so as to fire the cartridges in succession.

Description

United States Patent [1 1 Strubin DRIVE MECHANISM FOR ELECTRICAL SWITCHES [75] Inventor: Harald Strubin,Neuenhof,

Switzerland [73] Assignee: Brown Boveri & Company Limited, Baden, Switzerland [22] Filed: Sept. 8, 1972 [21] Appl. No.: 287,285

[30] Foreign Application Priority Data Sept. 23, 1972 Switzerland 13843/72 [56] References Cited UNlTED STATES PATENTS 6/1965 Perry ZOO/61.08 4/1969 Boop 200/82 R [451 Sept. 25, 1973 3,646,292 2/1972 Barkan et al 200/82 B Primary Examiner-Harold Broome Att0rneyRalph E. Parker et al.

[57] ABSTRACT A double-acting drive mechanism for actuating the contacts of an electrical switch between open and closed position includes a cylinder having a doubleacting piston therein and a piston rod extending through one end of the cylinder for connection to the contact actuating mechanism of the switch. Each end of the cylinder is closed by a stationary member having a. flanged portion provided with one or more circular rows of cartridge chambers serving as a magazine and which communicate with the corresponding end of the cylinder, and a latch-releasable spring-driven rotary member carrying a firing pin is mounted on each end closure member for the cylinder for rotation in a stepby-step manner around the row of cartridge chambers so as to fire the cartridges in succession.

9 Claims, 4 Drawing Figures DRIVE MEcHANlsMroa ELECTRICAL SWITCHES is impinged upon alternatingly in both directions by ignited detonating gas, the ignition being accomplished by spark plugs (German Patent 1,287,677.). Also known is a pressure gas switch where the cut-off is accomplished by arc quenching, and the drive by the ignition of cartridges filled with explosives which are replenished by a magazine clip, similar to a self-loading rifle (German Patent 568,887). The switching-on is accomplished here by spring force. Finally, there is known in view of the German published patent specification DT/AS 1,118,316 a switch drive wherein the switch-on direction apiston is moved by the ignition of cartridges in an explosion chamber, whereby the car- .tridges are delivered by means of a guide-slide magazine.

The primary object of the present invention is to provide a more simple solution where the transfer of cartridges by moving magazines is avoided but still providing a relatively large quantity of cartridges. The drive proposed by the invention is characterized by the features that both ends'of a cylinder which holds the driving piston, are closed off by flanged end membersdesigned to form a stationary cartridge magazine, whereby the. flanged endmembers are provided with a part that is rotatable by spring force, and which after the ignition of one cartridgecanalways be made ready to provide the next cartridge by the transitory release of the spring-activated turning device,.the release being controlled by the explosive gas, and that the rotatable part is provided with a striker pin and a duct which guides the explosive gases to the drive area.

The foregoing, aswell as other objects and advantages inherent in the invention will becomemore apparent from the following detailed description of a preferred embodiment thereof and from the accompanying drawings wherein: v i

FIG. 1 shows the improved drive in longitudinal cross-section, V

FIG. 2 is also a cross-section which depicts avariation in a detail of the cartridge arrangement in'FIG. v1;

and a FIGS. 3 and 3a are sections along the cutting line A A, with FIG. 3, 3a depicting the same cartridge arrangement as shown by FIG. 2.

With reference now to FIG. 1, the .double acting working piston 14 is seen to be located within cylinder 14a. Piston 14 is provided with a piston rod 14b,

connected to the contact mechanism of the switching apparatus which is not shown in detail. Both ends of the piston cylinder 14a are closedoff, each with one flanged end member 10. Inside the flanged end members, spaces and 6 are provided which can have volumes of different sizes. In the species depicted, the space 5 located at the left end of cylinder 14a which communicates with the left side of'pist'on I4 is larger so that with the use of identical cartridges, theenergy of thrust, acting in this direction, i.e.,.towards the right,

will have a lesser effect (switch-on direction). The thrust space 6 for the switch-off direction associated with the right end of cylinder 14a and the right side of piston 14 is kept smaller with the result that a desirable greater driving force of piston 14 and piston rod 14b to the left is generated. The cartridges 11 are accommodated in bores provided in the flanged end members 10, located along a single pitch circle or along two circles 1, 2 (FIG. 3). It will be advantageous in this connection, as shown by FIGS. 2 and 3, to arrange the bores of the smaller'pitch circle 1 so as to lie between the bores of the larger circle 2, because in this manner a greater number of bores, and consequently a greater number of cartridges 11 can be accommodated in the flanged end members 10.

Mounted for rotation on a cylindrical projecting part 10a of each of the flanged end members 10 and which is coaxial with an extension of the axis of cylinder 14a is a rotatable part 22 which is provided with a duct l2 which extends in a radial direction inwardly from the cartridge chamber 11a and terminates in a circumferentially extending passageway 12a which is in constant communication with the

spaces

5, 6 respectively by means of one or more bores 50, 6a through the wall of the mounting part 10a. The rotatable part 22 is provided with a longitudinally extending arm portion 22a which rotates in contact with the periphery of the flanged end member 10 and which is provided with a pivotally mounted lever 9 which, in the case of the embodiment depicted in FIG. 1, carries a single firing pin 4 having a stroke along a path intersecting the pitch circle defining the positions of the circumferentially spaced cartridge chambers l'la.

In the case of the embodiment according to FIG. 2, the corresponding lever 9' is provided with two

firing pins

4, 4 which are aligned respectively with each of the two concentric pitch circles 1 and 2 provided with the staggered circular rows of cartridge chambers 11a and 11b in which the cartridge 11 are fired in alternation.

It will be noted that dummy holes 3 are located along each of the two pitch circles in alternation with the cartridge chambers l laand 11b so that each time the firing pin lever 9 is actuated, one firing pin serves to detonatea cartridge along one pitch circle and the other firing pin enters a dummy hole 3 on the other pitch circle. 1

A magnetic system is utilized for effecting actuation of the firing pin lever 9, or 9' at each end of the cylinder 14a and flanged end member 10. As depicted in FIG. 1, each of the two magnetic systems includes a permanent magnet 7 having an annular configuration which concentrically surrounds the cylinder 14a and is supported by a radially extending flange 14b. Each annular magnet 7 is provided with an annular pole shoe 7a and includes an annular disc-shaped armature 8 carried by an annular support 25 which is slidable along and is guided by a cylindrical control coil 26 surrounding and supported by cylinder so as to provide for movement of armature 8 between the lever-striking position depicted at the left end of FIG. 1 at which the cartridge 11 is fired, and a retracted position depicted at the right end of FIG. 1 against the counter-action of a helical firing spring 24 located intermediate coil 26 and

magnet structure

7, 7a so as to lie in contact with the end of the pole shoe 7a. The magnetic flux produced by energization of coil 26 is counter to that produced by the permanent magnet 7 itself so that when coil 26 is not energized, the magnetic flux produced by magnet 7 is strong enough to hold armature 8 in the retracted position away from the

firing pin lever

9, or 9. However, when the flux-weakening coil 26 is energized, the force attracting armature 8 to the pole shoe 7a is lessened to the extent that the counterforce stored by compression of spring 24 is then sufficient to drive the support 25 and armature 8 so that the latter strikes lever 9 or 9' and causes the firing pin 4 to strike and detonate cartridge 11. The ensuing explosion gases pass through the

passageways

12, 12a and 50 into the chamber space and drive piston 14 and its piston rod 14b from the left hand, full line position at the left end of cylinder 14a depicted in FIG. 1 to the right hand, broken line position at the right end of cylinder 14a. As previously explained, piston rod 14b is coupled to the switch contact actuating mechanism and thus effects closing of the switch contacts.

As the pressure builds within the space 5 by the explosion gases, a portion of such gases passes outwardly through ducts 15 each of which lead from the space 5 and terminate at one end of a bore containing a tappet rod 8a which acts in the manner of a piston and drives against armature 8 forcing the latter to move in the opposite direction away from lever 9 against a counter force of spring 24 which is then re-compressed and reengage with pole 7a which then holds it in this attracted position, the release current pulse applied to the fieldweakening coil 26 then having been terminated, until the next firing action takes place.

Also mounted on the rotatable part 22 is a casing 28 enclosing a compression spring 20 which exerts its force against a tappet rod 17a slidable within a bore 16 which communicates with the circular passageway 12a. Connected to tappet rod 17a by means of a piston-like guide member 29 slidable within casing 28. is a resilient pawl 17 engageable with and controlling the operation of a latch lever, one end of this lever 18 being engageable with the pawl and the opposite end being arranged to engage in one of a circumferential array of grooves 21 provided at the periphery of the end member 10, as shown more clearly in FIG. 3a.

As soon as piston 14 moves past ports 19 in the wall of cylinder 14a, the pressure of the explosion gases will drop at the driving side, e.g., 5, thus dropping the pressure within bore 16 and permitting the force stored within compressed spring 20 to act through the pistonlike guide members 29 and shift tappet 17a and pawl 17 in the direction such as to cause a temporary rotation of the spring biased latch lever 18 to release it from the particular groove 21 with which it has been engaged. This shifted position of the tappet 17a, guide 29 and pawl 17 is depicted at the right end of FIG. 1.

A spirally coiled spring 23 is located in a recess b provided within each of the end members 10 and surrounds the cylindrical portion 10a. The inner end of spring 23 is anchored to the portion 10a and the outer end of spring 23 is provided with a driving dog 23a which engages a recess 22b provided in the rotatable part 22. The driving spring 23 is wound by rotating the part 22 about the end member 10 with the latch lever 18 disengaged.

When latch lever 18 is momentarily actuated by the shifting movement of pawl 17 so as to disengage the lever from a groove 21, the torque stored in the wound spring 23 will then cause the part 22 to rotate by one step or pitch along the pitch circle of the cartridge chambers at which instant it is then stopped by engagement of the latch lever 18 in the next adjacent groove 21. The pawl 17 and its associated structure will remain in the position depicted at the right end of FIG. 1 until the next cartridge is fired from the left end of FIG. I, at which time, the pressure build-up within the space 5 will cause the tappet 17a, guide 29 and pawl 17 to be shifted back to the position depicted at the left end of FIG. 1 in readiness to once again trip the latch lever 18 as soon as piston 14 has been driven far enough into its cylinder 14a to expose the ports 19 to the space 5.

As previously explained, the'operating arrangement for the cartridge magazine structure at each end of cylinder 14a is alike with the possible exception that the volume of space 5 is made somewhat greater than that of space 6 so as to provide a less forceful actuation of the switch contacts to the contact-closed position as piston rod 14b is driven from left to right as viewed in FIG. 1. The cartridges 11 are retained within their chambers by means of an annular ring 27 provided with an annular groove or grooves 27a depending upon whether one or two rings of cartridges are utilized which receive and press against the ends of the cartridges. Removal of ring 27 enables the cartridge magazine structure to be re-filled simply and quickly. While the

spaces

5 and 6 have essentially the same diameter and length, the differences in their respective volumes is attributable to the fact that piston rod 14b passes through the space 6 thus reducing its effective volume accordingly.

I claim:

1. In a double-acting drive mechanism for actuating the contacts of an electrical switch between their closed and open positions, the combination comprising a cylinder, a double-acting piston operable within said cylinder, a flanged end member for and closing off each end of said cylinder, the flanged portion of each said end member being provided with at least one circular row of circumferentially spaced chambers constituting a stationary magazine for receiving cartridges which upon detonation produce explosion gases for driving said piston from one end of said cylinder to the other, a piston rod extending through one of said end members and which is connectible to the switch contact actuating means, duct means establishing an explosion gas flow path between each of said cartridge chambers and the corresponding end of said cylinder, cartridge firing means including a firing pin mounted on said end member for rotation in a step-by-step manner along said row of cartridge chambers for effecting consecutive firing of the cartridges, actuating means for said firing pin, spring means for imparting a continuous torque to said rotary cartridge firing means, a latching device restraining rotation of said cartridge firing means at each cartridge chamber position, and means releasing said latching device after each cartridge is fired whereby said rotary cartridge firing means automatically steps to the next cartridge firing position.

2. A double-acting drive mechanism as defined in claim 1 for actuating the contacts of an electrical switch wherein each of said flanged end members is provided with a pair of concentric circular rows of circumferentially spaced cartridge chambers, the cartridge chambers of one row being circumferentially staggered with respect to the cartridge chambers of the other row, and wherein said cartridge firing means is provided with a firing pin serving each row of cartridge chambers.

3. A double-acting drive mechanism as defined in claim 1 for actuating the contacts of an electrical switch wherein said releasable latching device for restraining rotation of said cartridge firing means at each cartridge chamber position includes operating means therefor actuated by the explosion gases after said piston has been driven for a predetermined distance within its cylinder.

4. A double-acting drive mechanism as defined in claim 1 for actuating the contacts of an electrical switch wherein said firing pin is mounted on a lever and wherein said actuating means for said firing pin is constituted by a magnetic assembly including a stationary annular holding magnet surrounding said cylinder, an annular armature member also surrounding said cylinder and which is mounted for movement parallel to itself between said holding magnet and a position striking said firing pin lever, and a striker spring engaging said armature member for driving the latter against said firing pin lever when released from said magnet.

5. A double-acting drive mechanism as defined in claim 4 for actuating the contacts of an electrical switch wherein said holding magnet is of the permanent type and which further includes a release coil associated therewith, said release coil when energized producing a magnetic flux counter to the magnetic flux produced by said permanent magnet and which serves to weaken the effective attractive force and release said armature member.

6. A double-acting drive mechanism as defined in claim 4 for actuating the contacts of an electrical switch and which further includes means actuated by the explosion gases for resetting said armature member into engagement with said holding magnet and simultaneously storing a force in said striker spring.

7. A double-acting drive mechanism as defined in claim 1 for actuating the contacts of an electrical switch and wherein said duct means establish a flow path for the explosion gases from said cartridge chambers to the end of said cylinder includes a passageway leading through said rotary cartridge firing means into a space provided in said end member and which communicates with the end of said cylinder.

8. A double-acting drive mechanism as defined in claim 7 for actuating the contacts of an electrical switch wherein the effective volumes of the spaces provided respectively in said end members differ from one another so as to provide correspondingly different driving forces on said piston for its opposite directions of movement.

9. A double-acting drive mechanism as defined in claim 1 for actuating the contacts of an electrical switch wherein said latching device includes a latch lever mounted on said rotary cartridge firing means, one end of said lever being engagcable in each of a circular row of circumferentially spaced grooves provided in said end member, and the other end of said lever being actuatable by a pawl which in turn is actuated in response to the pressure created by the explosion gases. 4 =1: =0 1:

Claims

9. A double-acting drive mechanism as defined in claim 1 for actuating the contacts of an electrical switch wherein said latching device includes a latch lever mounted on said rotary cartridge firing means, one end of said lever being engageable in each of a circular row of circumferentially spaced grooves provided in said end member, and the other end of said lever being actuatable by a pawl which in turn is actuated in response to the pressure created by the explosion gases.