US3653139A

US3653139A - Firing mechanism for explosively actuated tool

Info

Publication number: US3653139A
Application number: US86565A
Authority: US
Inventors: Ernest E Temple; George E Heckathorne
Original assignee: Mine Safety Appliances Co
Current assignee: MSA Safety Inc
Priority date: 1970-11-03
Filing date: 1970-11-03
Publication date: 1972-04-04
Anticipated expiration: 1989-04-04

Abstract

A spring normally holds a sleeve in a forward position in a housing. Supported by the housing in the rear end of the sleeve is a stop, in front of which a firing pin driver is slidably mounted and provided with a rearwardly opening axial bore and a plurality of circumferentially spaced radial holes. A shuttle rod is slidably mounted in the bore, in the front end of which there is a spring normally holding the rod in a rear position in the driver. A spring in the sleeve normally holds the driver in a forward position spaced from the stop. The inside of the sleeve has a recess opposite the driver holes, and a detent in each hole engages the shuttle rod and projects into the adjacent recess. The rod has a depression behind the holes deep enough to receive the detents when they are not projecting into the recess. A trigger retracts the sleeve in the housing to pull the detents and driver backward until the detents enter the rod depression to permit the driver spring to move the driver and rod forward together to fire a cartridge. When the trigger is released, the sleeve spring moves the sleeve forward so that the sleeve recess can receive the detents again to thereby permit the shuttle spring to return the shuttle rod to its rear position.

Description

United States Patent Temple et a1.

1 51 Apr. 4, 1972 [54] FIRING MECHANISM FOR EXPLOSIVELY ACTUATED TOOL [72] Inventors: Ernest E. Temple, Murrysville; George E.

Ileckathorne, Pittsburgh, both of Pa.

Mine Safety Appliances Company, Pittsburgh,Pa.

[22] Filed: Nov.3, 1970 [21] App1.No.: 86,565

[73] Assignee:

Primary Examiner-Samuel W. Engle Attorney-Brown, Murray, Flick & Peckham [57] ABSTRACT A spring normally holds a sleeve in a forward position in a housing. Supported by the housing in the rear end of the sleeve is a stop, in front of which a firing pin driver is slidably mounted and provided with a rearwardly opening axial bore and a plurality of circumferentially spaced radial holes. A shuttle rod is slidably mounted in the bore, in the front end of which there is a spring normally holding the rod in a rear position in the driver. A spring in the sleeve normally holds the driver in a forward position spaced from the stop. The inside of the sleeve has a recess opposite the driver holes, and a detent in each hole engages the shuttle rod and projects into the adjacent recess. The rod has a depression behind the holes deep enough to receive the detents when they are not projecting into the recess. A trigger retracts the sleeve in the housing to pull the detents and driver backward until the detents enter the rod depression to permit the driver spring to move the driver and rod forward together to fire a cartridge. When the trigger is released, the sleeve spring moves the sleeve forward so that the sleeve recess can receive the detents again to thereby permit the shuttle spring to return the shuttle rod to its rear position.

10 Claims, 7 Drawing Figures PATENTEDAPR 41922 3,653,139

sum 2 or 3 PATENTEDAPR 41922 3,653,139

SHEET 3 OF 3 ATTORA/EKS.

FIRING MECHANISM FOR EXPLOSIVELY ACTUATED TOOL It is among the objects of this invention to provide an explosively actuated tool with a firing mechanism, in which a firing pin driver is retracted and then released by one continuous pull of a trigger, and in which release of the trigger then causes the firing mechanism to reset itself automatically.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a plan view of the tool when not in use, with parts shown in section;

FIG. 2 is a central longitudinal section;

FIG. 3 is a longitudinal section showing the tool pressed against a workpiece;

FIG. 4 is a fragmentary longitudinal section showing the firing mechanism at the instant the firing pin starts to be driven forward;

FIG. 5 is a view, similar to FIG. 4, showing the firing mechanism in fired position; and

FIGS. 6 and 7 are enlarged cross sections of the tool taken on the lines Vl-VI and VIIVII, respectively, of FIG. 2.

Referring to the drawings, the frame of a tool includes a heavy member that is long enough to receive the barrel of the tool as shown in FIG. 3. The rear end of this barrel receiver 1 is integral with the front end of a tubular trigger housing 2, which is supported by a handle 3 of any suitable construction. The front end of the receiver likewise is tubular. In between one side of the receiver, preferably the top side, is open to form a longitudinal channel 4. Screwed onto the tubular front end of the receiver is the collar 5 of an annular shield 6 that projects in front of the receiver.

A barrel 7 is disposed in channel 4 and normally projects from the front end of the receiver and from the shield as shown in FIGS. I and 2. This barrel is pivoted in the receiver on an axis transverse to the channel. Thus, the opposite sides of the portion of the receiver encircled by collar 5 are provided with aligned radial openings 9, in which pivot pins 10 are mounted that project into recesses 11 in the opposite sides of the barrel. The pins are retained in the recesses by the encircling collar, and of course are put in place before the collar is screwed back across openings 9.

The open side of channel 4 is long enough and wide enough to permit the rear end of the barrel to be tilted up away from the bottom of the channel as shown in FIGS. 1 and 2. To prevent the encircling front end of the receiver from interfering with this tilting of the barrel, the portion of the receiver above the barrel is provided with an arcuate recess 13 that is tapered forwardly as shown in FIG. 3, while the portion below the barrel is provided with an arcuate recess 14 that is tapered rearwardly from the front end of the receiver. The barrel is tilted up into the first recess and down into the second, as shown in FIG. 2. The barrel recesses 11 that receive the pivot pins are slots extending lengthwise of the barrel so that the barrel can slide back and forth within predetermined limits in the channel.

The barrel normally is in the tilted inoperative position because the rear end of a leaf spring 16, which is disposed in a groove in the bottom of the channel, presses up against the barrel. The front end of the spring is held by a rivet 17. Of course, the tool cannot be fired accidentally while the barrel is tilted. While tilted, the cartridge chamber 18 in the rear end of the barrel is readily accessible to the operator in case he wants to load the barrel with a cartridge 19.

The barrel can be swung down into the receiver, where it will be concentric therewith, by grasping the receiver and barrel in one hand and squeezing them together. When the barrel is in this lower or operative position it is directly in front of a breechblock 20 and it engages the front end of an ejector 21 slidably mounted in the tubular trigger housing. The ejector has a pair of parallel legs 22 extending back through radial notches 23 in the breech block that is screwed into the front part of the tubular housing. This breech block has a reduced central portion that extends forward toward the front of the ejector, but they are normally spaced apart by a coil spring 24 in the ejector. Forward movement of the ejector is limited by feet 25 on the rear ends of its legs engaging a shoulder 26 in the encircling housing.

The breech block is provided with a central passage, in which a firing pin 30 is disposed, and the pin projects into a central opening 31 in the ejector. A short distance behind the ejector feet 25 a sleeve 32 is slidably mounted in the tubular housing 2. This sleeve extends rearwardly through the front part of the handle and is attached by screws 33 to a trigger 34, by which the sleeve can be pulled back in the housing. It is normally held in its forward position by an encircling coil spring 35 that bears against a shoulder 36 near the front end of the sleeve.

The rear portion of the sleeve is provided with a pair of diametrically opposite slots 37 (FIGS. 1 and 7) that extend lengthwise of it. Extending across the sleeve and through these slots is a pin 38 that is anchored in the encircling housing. The pin also extends through a circular stop 39 inside the sleeve to hold the stop in fixed position relative to the housing.

Slidably mounted inside sleeve 32 is a firing pin driver 41 normally spaced from stop 39 by a coil spring 42 encircling the reduced rear portion of the driver and bearing against a radial shoulder on the driver. For the greatest safety, the firing pin should be joined to the driver. The driver is provided with a rearwardly opening axial bore 43 and with a plurality of circumferentially spaced radial holes 44. A shuttle rod 46 is slidably mounted in the bore of the driver, and a coil spring 47 in the front end of the bore presses against the rod and normally holds it against the stop 39. When the firing pin driver is in its forward position against the breech block, its radial holes are opposite a recess, such as an annular groove 48, in the inside of sleeve 32. Movably mounted in the holes are detents, preferably balls 49, that engage the outside of the shuttle rod and project into the encircling groove 48, thereby connecting the sleeve and the firing pin driver rigidly together as far as longitudinal movement is concerned.

Before this tool can be fired, the rear end of the barrel has to be swung down into the receiver channel. Then the front end of the barrel is placed against the object, into which a stud is to be driven, and the handle is pushed forward until the shield nearly engages the object as shown in FIG. 3. Forward movement of the receiver causes the trigger housing 2 to move forward around the ejector 21 engaging the barrel. When sleeve 32 engages the ejector feet, it stops, but the housing and breech block continue forward until the breech block contacts the ejector. The front end of the firing pin driver 41 now is spaced from the breech block, and the firing pin is nearly touching the cartridge. Since ejector feet 25 engage sleeve 32, and the firing pin and its driver are locked to the sleeve by balls 49, the pin cannot possibly move ahead until the trigger releases it.

To fire this tool, the trigger is pulled back and that retracts sleeve 32 against the resistance of its spring 35. Since the sleeve and firing pin driver are connected by balls 49, the driver and firing pin are retracted with the sleeve and compress driver spring 42 as well as the spring 47 inside the driver. When the driver has been retracted in this manner a certain distance, the balls reach an annular groove 51 in the shuttle rod 46, as shown in FIG. 4. The forward pressure of spring 42 against the driver then causes the balls to move inwardly into the rod groove, whereby the driver is released from sleeve 32 at the same time that the driver and shuttle rod are locked together by balls 49 and are driven forward by the expanding driver spring as shown in FIG. 5. The driver drives the firing pin forward against the cartridge to cause it to fire.

When the trigger is released, sleeve 32 is moved forward by its spring and when its annular groove 48 comes opposite the balls the pressure of the compressed rod spring 47 against the shuttle rod forces the balls out into the sleeve groove and thereby allows the rod spring to drive the shuttle rod back against stop 39. The parts of the firing mechanism are then back to their normal inoperative position, ready to fire the next cartridge that is inserted in the barrel.

It will be seen that this tool is cocked and fired simply by pulling on the trigger, which first retracts the firing pin driver and then releases it. After firing, release of the trigger automatically resets the firing mechanism, with nothing else to be done by the operator.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described,

We claim:

1. A firing mechanism for an explosively actuated tool, comprising a tubular housing, a sleeve slidably mounted in the housing, a coil spring encircling th e sleeve and normally holding it in a forward position in the housing, a stop disposed in the rear end of the sleeve and mounted in fixed position relative to the housing, a firing pin driver slidably mounted in said sleeve in front of the stop and provided with a rearwardly opening axial bore and a plurality of circumferentially spaced radial holes, a shuttle rod slidably mounted in said bore, a spring in the front end of said bore normally holding the shuttle rod in a rear position in the housing, a coil spring in said sleeve normally holding said driver in a forward position in the housing spaced from said stop, the inside of the sleeve having a recess therein opposite said holes, a detent in each hole engaging the shuttle rod and projecting into the adjacent recess, the shuttle rod having a depression therein behind said holes deep enough to receive the detents when they are not projecting into said recess, and a trigger for retracting the sleeve in the housing to pull the detents and driver backward until the detents reach said. depression, whereupon the detents will enter the depression to permit the driver spring to move the driver and shuttle rod forward together, the sleeve spring being designed to move the sleeve. forward in the housing when the trigger is released so that the sleeve recess can again receive the detents to thereby permit the shuttle spring to return the shuttle rod to its rear position.

2. A firing mechanism according to claim 1, in which said detents are balls.

3. A firing mechanism according to claim 1, in which said shuttle rod depression is an annular groove.

4. A firing mechanism according to claim 1, in which said sleeve recess is an annular groove.

5. A firing mechanism according to claim 1, in which said detents are balls and said recess and depression are annular W grooves.

6. A firing mechanism according to claim 1, in which the rear end portion of said sleeve is provided with a longitudinal slot, and a pin anchored in said housing extends through said slot and rigidly supports said stop within the sleeve.

7. A firing mechanism according to claim 1, in which the rear end of said shuttle rod normally engages said stop.

8, A firing mechanism according to claim 1, in which said sleeve and housing are provided with opposed radial shoulders engaged by the sleeve spring between them.

9. A firing mechanism according to claim 1, in which the rear end of said driver spring engages said stop.

10. A firing mechanism according to claim 1, including an ejector mounted in said housing in front of said sleeve and engaged by the sleeve when the ejector is moved forward by said housing.

Claims

1. A firing mechanism for an explosively actuated tool, comprising a tubular housing, a sleeve slidably mounted in the housing, a coil spring encircling the sleeve and normally holding it in a forward position in the housing, a stop disposed in the rear end of the sleeve and mounted in fixed position relative to the housing, a firing pin driver slidably mounted in said sleeve in front of the stop and provided with a rearwardly opening axial bore and a plurality of circumferentially spaced radial holes, a shuttle rod slidably mounted in said bore, a spring in the front end of said bore normally holding the shuttle rod in a rear position in the housing, a coil spring in said sleeve normally holding said driver in a forward position in the housing spaced from said stop, the inside of the sleeve having a recess therein opposite said holes, a detent in each hole engaging the shuttle roD and projecting into the adjacent recess, the shuttle rod having a depression therein behind said holes deep enough to receive the detents when they are not projecting into said recess, and a trigger for retracting the sleeve in the housing to pull the detents and driver backward until the detents reach said depression, whereupon the detents will enter the depression to permit the driver spring to move the driver and shuttle rod forward together, the sleeve spring being designed to move the sleeve forward in the housing when the trigger is released so that the sleeve recess can again receive the detents to thereby permit the shuttle spring to return the shuttle rod to its rear position.

2. A firing mechanism according to claim 1, in which said detents are balls.

5. A firing mechanism according to claim 1, in which said detents are balls and said recess and depression are annular grooves.

8. A firing mechanism according to claim 1, in which said sleeve and housing are provided with opposed radial shoulders engaged by the sleeve spring between them.