US3748413A

US3748413A - Explosive type circuit breaker with frangible printed circuit board

Info

Publication number: US3748413A
Application number: US00230837A
Authority: US
Inventors: R Sawyer
Original assignee: Cartridge Actuated Devices Inc
Current assignee: STURDOBE Corp A CORP OF DE
Priority date: 1972-03-01
Filing date: 1972-03-01
Publication date: 1973-07-24
Anticipated expiration: 1990-07-24

Abstract

An actuating device comprises a piston and cylinder unit having a piston with a metal forming configuration on the side thereof from which a piston rod projects, and a recess is provided in the rod adjacent the configuration. The arrangement is such that upon impact by that side of the piston on an end wall of the cylinder the material of the end wall is deformed into the recess to prevent rebound of the piston. The device is also illustrated in combination with an explosive operated initiating element.

Description

United States Patent [1 1 [111 3,748,413 Sawyer July 24, 1973 EXPLOSIVE TYPE CIRCUIT BREAKER 3,277,255 10/1966 Mattsson et al. ZOO/61.08 3,286,064 11/1966 Wilson et al ZOO/61.08 X RANGIBLE PRINTED ClRCUIT 3,334,204 8/1967 Brenny et al 200/82 R 3,641,289 2/1972 Dokopoulos ZOO/61.08

Inventor: Robert H. Sawyer, Bernardsville,

Cartridge Actuated Devices, Inc., Fairfield, N.J.

Filed: Mar. 1, 1972 Appl. No.: 230,837

Assignee:

U.S. Cl. 200/6l.08, 200/82 R Int. Cl. 1101b 39/00 Field of Search ZOO/61.08, 82 R;

References Cited UNITED STATES PATENTS 4/1960 Leaman ZOO/61.08 X

Primary Examiner-4. R. Scott Attorney-Albert C. Nolte, Jr. et al.

[ 5 7 ABSTRACT 6 Claims, 2 Drawing Figures Pmmiumm ww w EXPLOSIVE TYPE CIRCUIT BREAKER WITH FRANGIBLE PRINTED CIRCUIT BOARD From one aspect of this invention it is concerned with an actuating device, particularly one including a piston and cylinder element which is subject to a high motive force moving the piston from one position to another, but having a small retaining force for holding the piston in that position. From this aspect, it is an object of the invention to preclude rebound of the piston from said other position against the small retaining force.

From another aspect, the invention is concerned with a piston cylinder type actuating device in combination with an explosively operated initiating device including a circuit breaking means, in which combination a common explosive charge operates said initiating device and said actuating device.

So far as the first aspect of this invention is concerned, the most pertinent art of which applicant is aware is U. S. Pat. No. 3,234,727 which issued on Feb. I5, 1966 to H. C. Filer. That patent shows an explosively actuated motor comprising a piston and cylinder unit in which matching grooves are formed in the cylinder and in the piston and a deformable element is inserted into the cylinder between an end wall of the cylinder and the piston to be deformed upon actuation of the motor into the matching grooves thus to prevent rebound. The present invention provides an arrangement in which no groove is required in the cylinder wall, in which no assembly of a separate element between the end wall of the cylinder and the piston is required and which is effective to prevent rebound.

Insofar as the second apsect of this invention is concerned, the applicant is aware only of the material described in copending application Ser. No. 230,622 filed Mar. 1, I972 in the name of John H. McPherson. The present invention embodies the device of the aforementioned application in combination with a piston cylinder actuating device and particularly in combination with a piston cylinder actuating device of the kind according to the first aspect of this invention.

An embodiment of this invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a longitudinal cross section of a device according to the present invention; and

FIG. 2 is a detail of the device in FIG. 1 subsequent to actuation.

The .combination illustrated in the drawings comprises a circuit breaking device generally indicated at and described fully in the aforementioned copending application. That device comprises a housing 11, an anvil 12, a cutter 13, a plunger 14, and an explosive charge 15. Mounted between the anvil and cutter is a printed circuit board 16 across which a circuit is made between a conductor 17 in the anvil and a conductor 18 in the cutter. The anvil is provided with an appropriate recess 12' which receives the severed portion of the printed circuit board after the device is actuated.

It is to be noted that that portion of the device 10 containing the charge is closed by a washer element 20 which is held in position by crimping over the edges 21 of the body 11. This aspect of the invention and its relationship to the combination according to this invention will be described in greater detail hereinafter.

The body 11 is externally screw threaded as at 30. By means of these external screw threads 30, a cylindrical housing 50 is secured by corresponding internal screw threads 51 to the device 10.

The housing 50 has a cylindrical internal space 52 and an end wall 53 through which, and through an extension 54 of which, there is formed a guide opening 55. Mounted for sliding movement within the cylinder 52 is a piston comprising a head 60 and a rod or stem 62.

The head has an annular recess 64 formed in its generally cylindrical surface and within that recess is an O- ring 66 which cooperates with the walls of the cylindrical space 52 effectively to seal up the spaces of the cylinder to opposite sides of the piston head from each other.

The face 68 of the head constitutes a working face exposed to a motive force, which in this instance will be that resulting from the expansion of gases from the explosive charge 15 disposed in on explosive charge receiving chamber. The opposite face 70 of the head has a preferably annular metal deforming configuration 72. The metal deforming configuration 72 is, in this instance, of V-section defining a sharp edge 73 opposing the end wall 53 of the cylinder.

Adjacent to the configuration 73 and on the piston rod 62 is an annular recess 76 which is defined in part by a shoulder 77 which faces the piston surface 70 and the radially innermost face defining the V-section metal forming configuration leads towards that recess.

The enlarged portion 78 of the piston rod coacts with the central opening 55 of the end wall of the cylinder to guide the piston in its movement.

At the end of the piston rod, remote from the piston head, is a configuration which may be used for any actuating purpose, but is especially useful for making or breaking a circuit (not shown) externally of the device. For example only, the configuration 90 may be formed as a contact shearing device similar to cutter 13, for cutting an external circuit, or it may be formed as a bridging contact for an external circuit. In addition the configuration 90 may be used to cut or shear diaphragms for the release of pressure or opening of one chamber into another.

It will be appreciated that upon detonation of the charge 15, the piston head will be forcefully moved to the right, as viewed in FIG. 1, so that the edge 73 on face 70 of the piston head will strike the end wall of the cylinder. The material of the head and the material of the end wall of the cylinder, or the treatment of the forming configuration 72, or the shaping of the end wall of the cylinder, are such that as the piston strikes the end wall of the cylinder the material of that end wall will be swaged or deformed to move into the recess 76 and, by cooperation with shoulder 77, prevent rebound of the piston from the end wall of the cylinder. The end wall of the cylinder may be of any suitable material that is swageable or deformable, such as a metallic material, while the material of the configuration 72 is preferably of a harder material.

By carefully selecting the firmness by which the washer 20 is crimped to the end of housing I l relatively to the resistance of the printed circuit board 16 to being sheared by cutter 13, one can arrange that either piston 61 be moved to the right before the cutter is moved to the left, or, that the cutter move to the left before the piston moves to the right. In this way to achieve a make before break, or break before make" situation, where the configuration 90 at the outer end of the piston controls a circuit.

While the cutting edge 73 of the present invention is illustrated as being annular, it is to be appreciated that it could take the form of one or more teeth and be opposed to a recess in the piston rod of similar configuration to swage only a part of the end wall of the cylinder into that recess. According to a further modification of this invention, the end of the wall of the cylinder may have an upstanding portion which may be turned over upon impact by the piston edge to move into the recess 76.

What is claimed is:

1. In combination, a housing enclosing a circuit breaking device comprising an anvil, a cutter cooperating with the anvil, a printed circuit board between the anvil and cutter and including a circuit extending across a cutting edge of the cutter to be severed upon activation of the cutter, and an explosive charge receiving chamber within the housing disposed to that side of the cutter remote from the anvil for activation of said cutter; and a piston and cylinder actuation unit within the housing and at the side of the chamber opposite to the cutter, said piston having a working face exposed to the force of the charge on that side of the chamber remote from the cutter, and a piston rod on its opposite face extending to the exterior of said housing and including an operating configuration exteriorly of the housing for performing an operation exterior to the combination.

2. The combination of claim 1 wherein said piston working face is separated from said charge by a releasable element closing said chamber, that one of the cutter and element having least resistance to movement upon detonation of said charge being first to be moved and thereafter the other of said cutter and element being moved whereby said switching of the circuit of said printed circuit board and the external operation may be achieved sequentially.

3. The combination of claim 1 wherein said opposite face of said piston has a metal forming configuration and the piston rod adjacent said metal forming configuration has a recess defined at least in part by a shoulder disposed towards said opposite face of said piston whereby upon actuation of said device said metal forming configuration deforms material of an opposite end wall of said cylinder into said recess to prevent rebound of said piston.

4. The combination of claim 2 wherein said opposite face of said piston has a metal forming configuration and the piston rod adjacent said metal forming configuration has a recess defined at least in part by a shoulder disposed towards said opposite face of said piston whereby, upon actuation of said device, said metal forming configuration deforms material of an opposite end wall of said cylinder into saidrecess to prevent rebound of said piston' 5. Th combination of claim 2 wherein said releasable element comprises a disk releasably secured in an opening to said chamber.

6. The combination of claim 5 wherein said disk is crimped to the end of said chamber.

Claims

4. The combination of claim 2 wherein said opposite face of said piston has a metal forming configuration and the piston rod adjacent said metal forming configuration has a recess defined at least in part by a shoulder disposed towards said opposite face of said piston whereby, upon actuation of said device, said metal forming configuration deforms material of an opposite end wall of said cylinder into said recess to prevent rebound of said piston.

5. Th combination of claim 2 wherein said releasable element comprises a disk releasably secured in an opening to said chamber.