Plunger assembly

Abstract

A plunger assembly includes an outer elongated housing having an open end, an electric match having an electrical initiator and an explosive material, disposed in the housing. A plunger is disposed in and is moveable in the housing. A coupling device is provided for connecting the outer housing open end to a selected plunger receiver which is adapted to actuate a selected event. Application of an electrical charge to the initiator activates the explosive material to produce gas in the outer housing, which drives the plunger through the outer housing and into impact with the plunger receiver to actuate the selected event. In a preferred embodiment, the plunger assembly is a firing pin assembly and the plunger receiver is an explosive primer assembly.

Description

REFERENCE TO PENDING PRIOR PATENT APPLICATION

[0001] This patent application claims the benefit of pending prior U.S. Provisional Patent Application Serial No. 60/302,945, filed Jul. 3, 2001 by Paul A. Chambers for Electrically Fired Firing Pin Device, which patent application is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] This invention relates generally to plunger assemblies in which movement of a plunger into contact with a receiver is operative to initiate a selected event. In a preferred embodiment, the plunger is a firing pin and the selected event in detonation of an explosive primer.

BACKGROUND OF THE INVENTION

[0003] Initiation of an explosive, or an explosive train, usually is accomplished by imposing on the explosive, or primer therefor, a high voltage spark, or imposing on a primer a mechanical impact. In general, the high voltage spark system is used in multi-use devices and the mechanical impact system is used in disposable one-use systems.

[0004] The spark system requires the availability of a high voltage source, and impact systems are generally large and cumbersome, are adapted to provide an impact of a single preset force, and are not adapted to be fired remotely.

[0005] There is required a mechanical impact assembly which may incorporate a selected impact force and which can be initiated by an electrical charge of a selected voltage, to provide a suitable minimally required electrical charge to activate an impact on a given explosive primer.

[0006] More generally, there is need for a plunger assembly wherein the plunger in propelled by a minimally required electrical charge to activate a selected plunger receiver at a selected force to initiate a desired event. There is further required such an assembly as is relatively small and easy to handle, and which may be fired from a remote location.

SUMMARY OF THE INVENTION

[0007] An object of the invention is, therefore, to provide a relatively small, easy to handle and remotely activatable electrically actuated plunger assembly wherein a plunger is propelled at a selected force into impact with a plunger receiver for initiation of a desired event.

[0008] A further object of the invention is to provide such an assembly as a firing pin assembly wherein a firing pin is propelled at a selected force into impact with an explosive primer to initiate detonation of the explosive.

[0009] With the above and other objects in view a feature of the invention is the provision of a plunger assembly comprising an outer elongated housing having an open end, and an electric match, comprising an electrical initiator and an explosive material, disposed in the housing. A plunger is disposed in the housing and is movable in the housing. A coupling device is provided for connecting the outer housing open end to a selected plunger receiver adapted to activate a selected event. Upon application of an electrical charge to the initiator, the initiator actuates the explosive material to produce gas in the outer housing, which drives the plunger out the open end of the outer housing and into impact with the plunger receiver to actuate the selected event.

[0010] In accordance with a further feature of the invention, there is provided a firing pin assembly comprising an outer elongated housing having an open end, and an electric match, comprising an electrical initiator and an explosive material, disposed in the housing. A firing pin is disposed in the housing and is moveable in the housing. A coupling device is provided for connecting the outer housing open end to an explosive primer. Application of an electrical charge to the initiator activates the explosive material to produce gas in the outer housing, which drives the firing pin out of the open end of the outer housing and into impact with the explosive primer.

[0011] The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference is made to the accompanying drawings in which is shown an illustrative embodiment of the invention, from which its novel features and advantage will be apparent, wherein corresponding reference characters indicate corresponding parts in the views of the drawings, and wherein:

[0013] FIG. 1 in a perspective exploded view of one form of plunger assembly illustrative of an embodiment of the invention, shown with an exemplary plunger receiver; and

[0014] FIG. 2 is a generally centerline sectional view of the assembly of FIG. 1 in an assembled condition and joined to the illustrative plunger receiver.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0015] Referring to FIG. 1, it will be seen that an illustrative assembly 8 includes an outer tubular housing 10 having an open end 12. An electric match 14, comprising an electrical initiator and explosive material adjacent the electrical initiator, is disposed in the housing 10. A plunger 16 is disposed in the housing 10 and is moveable axially in the housing. A coupling device 18 is mounted rotatably on the open end 12 of the housing 10, being fitted on a flared collar 20 around the housing open end 12, as shown in FIG. 2.

[0016] The assembly 8 further includes structure, such as an inner tubular housing 22, disposed in the outer tubular housing 10, for retaining the electric match 14 in an appropriate position in the outer housing 10. The outer housing may be provided with crimped portions 24 for bonding the inner tubular housing 22 in place. Alternatively, the inner and outer housings may be bonded together adhesively by a bonding agent.

[0017] The coupling device 18 may be a nut adapted for interlocking engagement with a selected plunger receiver 30, the nut 18 being provided with a central bore 26 therethrough, the bore threadedly receiving a portion of the plunger receiver 30, to connect the assembly to the plunger receiver.

[0018] As shown in FIG. 2, the plunger 16 is disposed in the outer housing 10 at an open end 29 of the inner housing 22 and spaced from the open end 12 of the outer housing 10.

[0019] The assembly is provided with a plug 28 (FIG. 1) which, prior to use of the assembly, is engaged in the bore 26 of the coupling device 18 to close the interior of the assembly. The plug 28 may be removed, as by unscrewing, from the coupling device 18, and the plunger receiver 30 screwed into the coupling device in preparation for use of the assembly.

[0020] The electric match 14 is provided with a pair of electrical leads 32 which extend through the inner tubular housing 22 and out a closed end 34 of the outer tubular housing 10, and are connectable to a power source (not shown).

[0021] In a preferred embodiment of the invention, the assembly herein described constitutes a firing pin assembly, the plunger 16 constitutes a firing pin, and the plunger receiver 30 constitutes an explosive primer assembly, including a primer 36 (FIG. 2).

[0022] In preparing for use of the assembly 8, the assembly is taken from a protective package (not shown) and the plug 28 is removed from the nut 18. The nut 18 is then attached to the primer assembly 30 and the electrical leads 32 are attached to the power source.

[0023] Upon closure of a switch, as by pushing a button, squeezing a trigger, or as by a monitoring device, or time-activated device, or the like (not shown), current is directed to the electric match initiator which detonates the electric match explosive material to produce gas which drives the firing pin 16, which accelerates through the space between the firing pin 16 and the primer 36, and into impact with the primer 36 to detonate an explosive.

[0024] In the broader context of the invention, the gas drives the plunger 16 into impact with the plunger receiver 30 to actuate a desired event, such as sounding an alarm, flowing fire-quenching matter into an area, shutting down a power generator, or the like.

[0025] There is thus provided a small, easily handled plunger assembly activated electrically either locally or remotely, manually or automatically. Typically, the plunger assembly, less the outwardly extending lead wires, is about four inches or so, in length. The electric match component, described hereinabove, is a well-known commercially available part, available in several explosive weights and powers, and activatable by different voltages. Thus, for a particular application, a user can select an electric match activated by a very low voltage, as by a small battery, or by higher voltage, and having a relatively low explosive power. Conversely, the match can exhibit a high explosive power, initiated by a pulse of a suitable selected voltage.

[0026] It will be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principles and scope of the invention as expressed in the appended claims.

Claims

1. A plunger assembly comprising:

an outer elongated housing having an open end;

an electric match, comprising an electrical initiator and an explosive material, disposed in said housing;

a plunger disposed in said housing and moveable in said housing; and

a coupling device for connecting said outer housing open end to a selected plunger receiver adapted to actuate a selected event;

wherein application of an electrical charge to said electric match initiator activates said electric match explosive material to produce gas in said outer housing which drives said plunger through said outer housing and into impact with the plunger receiver to activate the selected event.

2. The assembly in accordance with claim 1 and further comprising structure disposed in said outer housing for retaining said electric match.

3. The assembly in accordance with claim 2 wherein said retaining structure comprises an inner housing.

4. The assembly in accordance with claim 3 and further comprising means for retaining said inner housing in place in said outer housing.

5. The assembly in accordance with claim 4 wherein said housings are tubular members and said outer housing is bonded to said inner housing to effect the retaining of said inner housing.

6. The assembly in accordance with claim 3 wherein said plunger is disposed at an open end of said inner housing and said plunger is moveable by the gas to drive said plunger from an open end of said inner housing and thereafter through said outer housing and into the impact with the plunger receiver.

7. The assembly in accordance with claim 1 wherein said coupling device comprises a nut adapted for interlocking engagement with the open end of said outer housing and the selected plunger receiver, and having a central bore extending therethrough.

8. The assembly in accordance with claim 7 and further comprising a removable plug disposed on said nut for closing the central bore therethrough.

9. The assembly in accordance with claim 1 wherein the electric match is provided with electrical leads extending therefrom for connection to an electrical power source.

10. The assembly in accordance with claim 9 wherein the electrical leads extend through said outer tubular housing and extend outwardly from a second end of said outer tubular housing.

11. A firing pin assembly comprising:

an outer elongated housing having an open end;

an electric match, comprising an electrical initiator and an explosive material, disposed in said housing;

a firing pin disposed in said housing and moveable in said housing; and

a coupling device for connecting said outer housing open end to an explosive primer assembly;

wherein application of an electrical charge to said electric match initiator activates said electric match explosive material to produce gas in said outer housing which drives said firing pin through said outer housing and into impact with the explosive primer assembly.

12. The assembly in accordance with claim 11 and further comprising structure disposed in said outer housing for retaining said electric match.

13. The assembly in accordance with claim 12 wherein said retaining structure comprises an inner housing.

14. The assembly in accordance with claim 13 and further comprising means for retaining said inner housing in said outer housing.

15. The assembly in accordance with claim 14 wherein said housings are tubular members and said outer housing is crimped into engagement with said inner housing to effect the retaining of said inner housing.

16. The assembly in accordance with claim 14 wherein said firing pin is disposed at an open end of said inner housing and said firing pin is moveable by the gas to drive said firing pin from the open end of said inner housing and thereafter through said outer housing and into the impact with the primer assembly.

17. The assembly in accordance with claim 11 wherein said coupling device comprises a nut adapted for interlocking engagement with the open end of said outer housing and with the primer assembly.

18. The assembly in accordance with claim 11 wherein the electric match is provided with electrical leads extending therefrom for connection to an electrical power source.

19. The assembly in accordance with claim 18 wherein the electrical leads extend through said outer tubular housing and extend outwardly from a second end of said outer tubular housing.