US3155039A - Safety plug for explosive cartridge - Google Patents

Description

a 1 MN) \l3C s/mu m/ FHW/AWUTLFQ. (m. WW. M \ni. iIW b V w Wm l0 Q1 l. m c m W W Nov. 3, 1964 w. F. BROSKE SAFETY PLUG FOR EXPLOSIVE CARTRIDGE Filed July 2, 1962 United States Patent 3,155,039 SAFETY PLUG FOR EXPLGSIVE CARTGE William F. Broske, Camp Hill, Pa, assignor to All? Incorporated, Harrisburg, Pa. Filed July 2, 1962, Ser. No. 206,767 4 Claims. (Cl. 102-38) In the use of powder-actuated tools for industrial purposes, I have discovered that a plastic cartridge may be used to advantage, especially of a construction wherein the cartridge has a centrally-located plug and the primer is disposed in the plug, as described in my prior application Serial No. 793,814, filed February 17, 1959, now Patent No. 3,007,409.

Upon inserting the shell into a tool, an air pocket may form in the casing and cause the firing pin to move forward ahead of it. After the shell is inserted into the tool, it is necessary to retract the firing pin to place the tool in operative condition. While it is recommended that the tool operator does not use his fingers in retracting the firing pin, there is always the possibility that he will do so. If he moves the firing pin too quickly, he may inadvertently actuate the device. This is especially true if the firing pin sticks while it is being retracted, and the operator tries to force the pin into position.

It is an object of the invention to provide such a plastic cartridge having a novel plug which prevents actuation of the cartridge when the firing pin is being retracted, but permits the cartridge to be fired after the tool is loaded.

It is a further object of this invention to provide a series of prongs on the front of the plug to protect the primer against a rearward thrust of the firing pin. However, these prongs may be disabled by rotating the cartridge relative to the firing pin, thus bending them out of position prior to firing.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 illustrates a perspective view (partially broken away) of a plug embodying the principles of this invention;

FIGURE 2 illustrates a tool having a cartridge containing the device of FIGURE 1 therein, in inactive condition;

FIGURE 3 is a view similar to FIGURE 2 showing the cartridge ready for firing;

FIGURES 4, 5 and 6 are views of the plug shown in FIGURE 1 in conjunction with a fragmentary view of the firing pin during the various stages of loading and firing; and

FIGURE 7 is a top sectional view taken through plane 7-7 of FIGURE 5.

As shown in FIGURE 1, the plug comprises a cylindrical member 10, preferably made of polyethylene or other plastic material. One end of the plug 10 has a major coaxial aperture 12 adapted to receive and support a priming means 14. The other end of the plug has a minor coaxial aperture 16, which permits the primer to actuate a powder charge when the primer is ignited. A

ice

series of V-shaped grooves 18- extend circumferentially around the outer surface of the plug. These grooves permit a tight engagement between the outer surface of the plug and the inner surface of the cartridge, thus acting as a gas check.

A plurality of longitudinally-extensible prongs or legs 2% project from the surface of the plug in which the primer is inserted. While any number of legs may be employed, in the preferment (FIGURE 1) four such legs are disposed about the primer at from each other. These legs may be of the same material as the plug and may be integral with the plug. The legs extend a sulficient distance to protect the primer against the firing pin when the firing pin is driven toward the primer. However, they are so constructed so that when there is a rotary motion between the firing pin and the plug (FIGURES 4 and 5), the legs will be bent out of the way quite easily and permit the firing pin to strike the primer.

To provide additional background on the use of the invention, FIGURES 2 and 3 illustrate a powder-actuated, industrial tool suitable for employng an exposive device containing a plug as set forth in FIGURE 1. FIGURE 2 shows the device after loading the shell, but prior to converting it from its inactive to its active condition.

The tool of FIGURES 2 and 3 includes a body member B adapted to receive a C-shaped connector 30 with a central wedge 32 slidable therein to grasp a pair of conductors C and C. (This is disclosed in a prior application, Serial No. 172,183, filed February 9, 1962.)

One end of the body member has an internally-threaded aperture 34 adapted to receive a housing 36 with external screw threads. The housing 36 is secured to a sleeve 33 which retains a firing chamber 49 therein. A cap 42 is adapted to be threaded onto the free end of the housing 40. A cartridge 44 is insertable into the firing chamber, and has a head 46 on one end which retains it against one end of the firing chamber. An explosive charge 43 is contaned in the shell, and the plug 10 (as previously described in FIGURE 1) is inserted into the shell with a friction-fit to retain the explosive charge therein. A flange 49 on the firing chamber 40 abuts a setscrew 50 to permit sliding motion between the sleeve 38 and the firing chamber, but permits them to travel together in a rotary direction. A firing pin 52 is slidable in the firing chamber and penetrates the open end of the shell 44. The other end of the firing pin comprises a head member 53 which projects from the housing 36 and, when fired, bears against the wedge 32 to drive it into position (see FIGURE 3).

A prong 54 projects from the cap 42 to puncture the head 46 of the shell 44 and permits the escape of gases when it is desired to Withdraw the cartridge.

Operation-When it is desired to connect a pair of conductors, the connector 30, wedge 32, and conductors C and C are positioned in the body member B. A can tridge 44 is inserted into the firing chamber 40 and the cap 42 secured to the firing chamber to retain the shell therein. The firing pin 52 is moved into its rearward position (as shown in FIGURE 2), whereby the legs 20 prevent the firing pin from being driven against the primer 14. An attempt to drive the firing pin toward the primer puts the legs under compression, and thus protects the primer against accidental ignition.

The barrel 38 is then rotated in a clockwise direction causing the screwthreads 34 to move the firing chamber inwardly until the head 53 touches the Wedge 32. Continuing the threading operation causes the head 53 to be frictionally retained against the wedge 32, and thus provides a rotary motion between the firing pin 52 and the legs 20. Although the legs 20 resist compression in a longitudinal direction, they may be bent over fairly easily in sidewise direction. As shown in FIGURE 5, they are thus deformed out of a position wherein they protect the primer, and into a position permitting the firing pin to be driven against the primer (see FIGURE 3).

The cap 42 may be struck a sharp blow (e.g., with a hammer or a pair of pliers), and the cap 42 and firing chamber 40 will be driven longitudinally toward the housing 36, thus driving the plug against the firing pin 52 and causing the firing pin to ignite the primer 14. Ignition of the primer 14 explodes the charge 48 and causes it to be driven forwardly, driving the firing pin ahead of it. The forward motion of the firing pin causes it to drive the wedge 32 into the connector 30, thus making a secure electrical connection.

. Thus itiistseen that the legs 20, While having a high com- 7 pressive strength, to protect the primer against inadvertent ignition, are relatively flexible in a sidewise direction which permits them to be folded out of the way prior to firing the device. The design of the plug 10 eliminates the human error in the use of a safety device, since the operator is not required to set or unlock a safety mechanism, nor can he disable it.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. A plug for use in an explosively-operated tool comprising: a cylindrical member having a primer-receiving means in one end thereof, a primer in said primer-receiving means, a plurality of projections extending from said plug and surrounding said means, said projections having high compressive strength in a longitudinal direction but being relatively flexible in a transverse direction so that they can be bent out of the way prior to firing the cartridge.

2. A cartridge for a powder-actuated tool comprising: a cylindrical shell closed at one end, a powder charge in said shell adjacent said closed end, a plug in said shell for retaining the powder charge therein, a percussion primer in said plug, said primer exposed to the open end of the shell, and means for preventing inadvertent actuation of said primer.

3. A cartridge for a powder-actuated tool comprising: a cylindrical shell closed at one end, a powder charge in said shell adjacent said closed end, a plug in said shell for retaining the powder charge therein, a primer in said plug, said primer having an actuating surface exposed to the open end of the shell, a plurality of members projecting from said plug toward the open end of said shell, said members capable of resisting force applied in a longitudinal direction while capable of being easily bent by a transverse force.

4. A cartridge for a powder-actuated tool comprising: a cylindrical shell closed at one end, a powder charge in said shell adjacent said closed end, a plug in said shell for retaining the powder charge therein, a primer in said plug, said primer having an actuating surface exposed to the open end of the shell, said plug made of a plastic material, a plurality of integral members projecting from said plug toward the open end of said shell.

References Cited in the tile of this patent UNITED STATES PATENTS 1,040,762 Rodrigues Oct. 8, 1912 2,345,618 McCormick Apr. 4, 1944 2,441,907 Schmitt' May 18, 1948 2,640,184 Bauer May 26, 1953 3,007,409 Broske NOV. 7, 1961 3,009,419 Clay Nov. 21, 1961

Claims (1)

1. A PLUG FOR USE IN AN EXPLOSIVELY-OPERATED TOOL COMPRISING: A CYLINDRICAL MEMBER HAVING A PRIMER-RECEIVING MEANS IN ONE END THEREOF, A PRIMER IN SAID PRIMER-RECEIVING MEANS, A PLURALITY OF PROJECTIONS EXTENDING FROM SAID PLUG AND SURROUNDING SAID MEANS, SAID PROJECTIONS HAVING HIGH COMPRESSIVE STRENGTH IN A LONGITUDINAL DIRECTION BUT BEING RELATIVELY FLEXIBLE IN A TRANSVERSE DIRECTION SO THAT THEY CAN BE BENT OUT OF THE WAY PRIOR TO FIRING THE CARTRIDGE.

Images