US3652003A

US3652003A - Powder actuated tool

Info

Publication number: US3652003A
Application number: US26022A
Authority: US
Inventors: Ignazio Leonardo; Harold C Pfeiffer
Original assignee: General Cable Corp
Current assignee: General Cable Corp
Priority date: 1970-04-06
Filing date: 1970-04-06
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28

Abstract

A powder actuated tool including a barrel with a muzzle affixed to one end is disclosed. A cylinder is movable within the barrel and a piston having a piston rod extending through the muzzle is movable within the cylinder. Stop means are located in the cylinder and the guidepin is located on the barrel. Adjustable means are provided for varying the stroke length of the piston within the cylinder and means are provided for increasing the service life of the piston rod.

Description

United States Patent Leonardo et al.

'[4 1 Mar. 28, 1972 POWDER ACTUATED TOOL Ignazio Leonardo, Mountainside; Harold C. Pfellier, Roselle Park, both of NJ.

General Cable Corporation, New York, NY.

Filed: Apr. 6, 1970 Appl. No.: 26,022

Inventors:

Assignee:

U.S. Cl ..227/l0, 227/8 int. Cl. .325: 1/14 Field of Search ..227/8, 9, 10, ll

[56] References Cited UNITED STATES PATENTS 2,970,314 2/1961 Temple et al .,227/8 3,171,131 3/1965 De Caro etal ..227/l0 1 Primary Examiner-Granville Y. Custer, Jr.

Attorney-Kenyon & Kenyon Reilly Carr & Chapin [57] ABSTRACT 5 Claims, 12 Drawing Figures Mcllvin .1. 227/8 POWDER ACTUATED TOOL This invention relates to a powder actuated tool of the type utilizing an explosively actuated piston to drive fasteners into construction material. In particular, the present invention is for a powder actuated tool of the type herein described where the stroke of the piston and the explosive force imparted to the piston can be easily and simply varied and where the piston is designed to have a long service life.

It has been known in the prior art to use an explosive projectile to provide an actuating force for the piston of a powder actuated tool wherein the piston was used to impart force to a fastener such as a bolt or stud, etc. in order to drive the fastener into a materiahln particular, it has been known to use such powder actuated tools in the construction trades where they have been used to drive nails and other fastening items into concrete and steel walls. Generally, this was done by using an explosive projectile to apply a force to one side of a piston having a piston rod and utilizing the free end of the piston rod to abut a nail or other fastener to drive a fastener into a construction material. While these prior art devices were generally successful in applying sufficient force for propelling the fastener through a material there were a number of disadvantages associated with these prior art tools which limited their use.

A first such disadvantage of these prior art powder tools was that it was extremely difficult in these tools to adjust the stroke of the piston and the amount of explosive force applied to the piston and hence the force applied to the fastener which the piston was to move. it is important to be able to control the force applied to the piston and hence the fastener which is moved thereby since if a sufficient amount of force is not applied to the fastener it will not be able to penetrate the material it is aimed at. Similarly if too much force is applied to the piston the fastener may crumble the material it is supposed to penetrate. One prior art device taught moving the piston rod relative to the piston to vary the stroke of the piston rod and the amount of force imparted to the fastener. Obviously, this was a time consuming and awkward technique.

A further disadvantage of prior art powder tools was that very often the free end of the piston rod which was used to supply an impact force to a fastener would fracture or otherwise fail after a relatively limited period of use. This required the use of a new piston rod after each such failure. This of course detracted from the value of the powder actuated to'ol since the replacing of the defective piston rod and piston with a new piston and piston rod was time consuming and expensive while otherwise slowing up the job for which the tool was being used.

it is thus apparent that if a powder actuated tool could be devised in which the force applied by the tool to a fastener could be varied so as to be able to efficiently drive a fastener into materials of different hardnesses it would find widespread use. If the powder actuated tool could also be designed so that the piston rod which is attached to the piston and used to supply an impact force to the fastening device would have a long service life and not fracture or otherwise fail after a limited number of uses it would add to the desirability of the tool.

It is therefore an object of the present invention to provide an improved powder tool of the type wherein an explosive projectile is utilized to provide the force for driving a fastener into a material.

A further object of the present invention is to provide an improved powder actuated tool of the type utilizing an explosive projectile to supply the force required to drive a fastener into a material wherein the force that is supplied by the explosive projectile to the fastener can be varied. 7

Another object of the present invention is to provide an improved powder actuated tool of the type utilizing an explosive projectile to provide the force required to drive a fastener wherein the length of travel of the fastener during which a positive force is applied to the fastener can be simply and accurately controlled.

Still another object of the present invention is to provide an explosively actuated powder tool that utilizes a driven member to drive a fastener wherein the driven member has a long service life and will not fail after a relatively limited number of uses.

Still a further object of the present invention is to provide an explosively actuated powder tool of the type herein described 7 wherein the powder actuated tool will be economical to make,

reliable in operation and simple to use.

Briefly, in accordance with the present invention, the foregoing and other objects are accomplished by a powder actuated tool having a barrel with a muzzle affixed to one end thereof. A firing mechanism is fixed relative to the barrel housing at one end of the barrel with a trigger provided to actuate the firing mechanism. The barrel is movable within the barrel housing and a piston having a piston rod extending through the muzzle is movable within the barrel. Stop means are located on the barrel and a guide pin is located on the barrel housing.

When it is desired to fire the tool a fastener is placed in the open end of the muzzle and a cartridge is placed in a cartridge receiving opening in the barrel. The tool is cocked by urging the muzzle against the material the fastener is to be projected into and as a result of this urging moving the barrel, and hence the piston along therewith, to the rear of the barrel housing so as to cock the firing mechanism in the tool. Upon actuation of the trigger the cartridge is exploded supplying an impact to the piston and piston rod forcing the fastener in the muzzle into the material the muzzle is pressed against. The barrel is then thrown open to extract the cartridge with the stop pin limiting movement of the barrel relative to the barrel housing by abutting a portion of the barrel housing. The guide pin in turn limits movement of the piston relative to the barrel.

An adjusting nut is located'on the barrel housing and movable relative thereto for varying the travel of the barrel relative to the barrel housing when the cylinder is thrown open by changing the location of the barrel housing on which the stop pin abuts. By varying the movement of the cylinder relative to the barrel when the cylinder is opened the guide pin varies the position of the piston relative to the barrel as the barrel is opened since the piston moves with the barrel when it is opened. Due to the friction between the piston and barrel the piston does not move relative to the barrel as the barrel is moved in the barrel housing to cock the tool and thus the position of the piston in the cocked tool is determined by the adjusting nut setting.

The position of the piston in the barrel determines the force applied to the piston by the cartridge since the position of these two elements relative to each other determines the volume in which the explosive force directed to the piston is dispersed in. The larger this volume the greater the dissipation of this force and thus a corresponding decrease in the force applied to the piston and vice versa.

Other objects, aspects and feature of the present invention will be apparent from the following specification and drawings in which:

FIG. 1 is a side elevational view of a powder tool in accordance with the present invention with the tool in the breach closed position;

FIG. 2 is a top plan view of the tool illustrated in FIG. 1;

FIG. 3 is an exploded view which illustrates the portions of the barrel housing and barrel of the present invention that prevent the barrel housing and barrel from rotating relative to each other;

FIG. 4 is an opened side elevational view of the powder actuated tool of the present invention in a breach opened position with the cartridge that is used to actuate the tool being ejected from the open breech of the tool and the tool set to impart maximum force to a fastener;

FIG. 5 is an opened side elevational view of the tool of the present invention in a breech closed, fully loaded uncocked condition wherein the tool is set to impart maximum force to a fastener;

FIG. 6 is an opened side elevational view of the tool of the present invention as shown in FIG. 5 in a loaded breech closed cocked condition;

FIG. 7 is an opened side elevational view of the tool of the present invention illustrated in FIG. 6 subsequent to the cartridge therein being fired;

FIG. 8 is a view along lines 8-8 of FIG. 7 showing the geometrical relationship between the firing pin hole, the firing pin plunger hole and the receptacle for the cartridge ejector mechanism of the present invention;

FIG. 9 is an enlarged open view along lines 9-9 of FIG. 8 showing the ejector mechanism of the present invention with a cartridge in the tool and the barrel in a position to cock the fir- FIG. is an enlarged open view taken along lines 9-9 of FIG. 8 showing the ejector mechanism of the present invention ejecting a cartridge after it has been spent and while the barrel is being moved relative to the barrel housing;

FIG. 11 is an enlarged open view of the piston, barrel and barrel housing of the present invention with the barrel housing open and the tool set to impart less than the maximum force it is capable of imparting to a fastener; and

FIG. 12 is an enlarged open sectional view of the tool of the present invention as seen in FIG. 11 in a loaded barrel closed cocked condition.

Referring now to the drawings and FIG. 1 in particular wherein a powder tool 10 according to the present invention is seen to include a handle portion 11 and a barrel housing 12 rigidly secured thereto. Located about barrel housing 12 is a threaded adjusting nut 13 which, as will soon be apparent, serves to adjust the stroke length of the firing piston of tool 10 and the explosive force applied thereby. Located at the lowermost portion of the tool, as viewed in FIG. 1, is a muzzle cap 14 and a muzzle l5. Barrel housing 12 at its leftmost portion,

as viewed in FIG. 1, includes a U-shaped slot 16 with a series of marked indicating lines 17 located on the outer surface of the barrel housing (FIG. 2) and to the left of slot 16. A slotted extension 51 is located at the bottommost portion of slot 16. The function of threaded adjusting nut 13 and indicating lines 17 in controlling the amount of explosive force imparted to a fastener which is to be driven by tool 10 and the length of travel of the fastener can be controlled extremely accurately by the cooperation of adjusting nut 13 and indicating lines 17 as will hereinafter be explained.

Referring now to FIG. 5 which is an opened side elevational view of the present invention where barrel housing 12 is seen to include at its uppermost portion firing pin chamber 17 and firing pin plunger chamber 18. As can be seen from FIG. 5, the firing pin chamber 17 is to the left of the firing pin plunger chamber 18 with tool 10 held in the position shown in this figure. A closure member 19 flanks the uppermost portion of barrel housing 12 as viewed in FIG. 5 and defines the uppermost extremity of firing pin chamber 17 and firing pin plunger chamber 18, while breech block 24 defines the lowermost extremity of these chambers.

Firing pin chamber 17 is a circular chamber having a slot 17a at its rightmost portion extending for the length of the chamber for a purpose soon to be explained. Housed within firing chamber 17 is.a firing pin 20 which includes

lands

21 and 22 separated by post 23 with the lands slideable within firing pin chamber 17. A firing pin hole 25 is located in breech block 24 and a firing pin 26 projects from land 22 and is adapted to project through the firing pin hole when firing pin 20 is in the position illustrated in FIG. 5. A spring 20a housed in firing pin chamber 17 biases the firing pin to the position seen in FIG. 5.

Located in firing pin plunger chamber 18 is a firing plunger 29 which has a post 28 at its lowermost extremity as viewed in FIG. 5. Post 28 is adapted to project through a firing post hole 27 in breech block 24 when the firing plunger is in the position shown in FIG. 5 under the bias of a spring 30 in firing plunger chamber 18. Plunger 29 includes a scar pin hole 31 which is perpendicular to the major axis of the plunger. A slot 33 extends along the length'of firing plunger chamber 18 and a sear pin 32 projects through slot 33, sear pin hole 31 and slot 17a so that its free end rests between

lands

21 and 22. A flanged cam follower 32a is located in sear pin 32 with a spring 34 wrapped around the bottom of the sear pin and resting against flanged cam follower portion 32a thereof. The bottom of spring 34 rests against disc 100 which in turn rests on ledge 35, the ledge being integral with closure member 19.

A trigger mounting 36 is affixed to the right portion of barrel housing 12 and includes a post 36a. A trigger 37 includes a slot 37a through which post 36a projects with the left portion of the trigger flat and slideable along the right portion of barrel housing 12. The upper most portion of trigger 37 includes a cam surface 37b which cooperates with flanged cam follower 32a in a manner to be hereinafter described. Trigger 37 includes a trigger spring post 38 with a spring 39 biasing the trigger in a downward direction as viewed in FIG. 5 so that post 360 is in the uppermost portion of slot 37a.

A barrel 40 is slidably positioned within barrel housing 12 and has attached thereto a stop pin 41 which projects through the slot 16 in the at the top of barrel housing 12. The uppermost portion of barrel 40 includes a cartridge receiving opening 42 which is adapted to receive a blank firing cartridge. Cartridge receiving opening 42 extends to a piston chamber 43 which is located within cylinder 40. The rightmost portion of cylinder 40 includes an opened slot 44 for a reason soon to be apparent. Located within the chamber 43 is a piston 45 having an elongated piston rod 46 attached thereto with a bumper guard 200 located on the piston rod adjacent the piston. The lowermost portion of elongated piston rod 46 includes a hollow impact port 47 which is an important aspect of the present invention. A guide pin 48 is rigidly secured to barrel housing 12 and projects through slot 44 so as to abut piston 45 when the piston moves downwardly as seen in FIG. 5.

The lowermost portion of barrel 40 includes threads 40a which mesh with threads 14a on muzzle cap 14. The adjusting nut 13 surrounds the lower portion of barrel housing 12 and is threadedly mounted thereto. Threaded portion 13a of adjusting nut 13 is in mesh with the threads 50a on barrel housing 12 for a reason soon to be apparent. An O-ring 49 is located between adjusting nut 13 and barrel housing 12 as well as between barrel housing 12 and barrel 40.

Muzzle 15 includes a flanged portion 15a which has a stop 15b on it (FIG. 3) which is adapted to be recessed in a slot receiving opening 40b on the threaded portion of barrel 40. By having stop 15b of muzzle 15 project into opening 40b on cylinder 40 relative rotation between the muzzle and cylinder is prevented. The lowermost portion of the interior of muzzle 15 as viewed in FIG. 5 includes a stop portion 15c, the purpose a of which will soon be apparent.

As seen in FIGS. 9 and 10 an ejector mechanism is provided for ejecting a cartridge from the tool subsequent to the tool being fired when the breech is opened and the barrel is moved to the downwardly relative to the barrel housing. The ejector mechanism includes an ejector spring rod 53 which has a curled finger portion 53a at one end that projects into the uppermost interior of the enclosed volume defined by breech block 24 and the uppermost portion of barrel 40. Ejector rod 53 is secured to an ejector collar 54 which is fixed within an ejector plunger cylinder 55, the relation between ejector col- Iar cylinder 55, firing pin hole 25 and firing plunger hole 27 being readily apparent from FIG. 8.

As can be seen in FIGS. 9 and 10 the upper rightmost portion of barrel 40 includes a cutaway chamfered slot 400. The cross-section of cutaway slot 400 forms an acute angle with a line extending axially through the rightmost portion of barrel housing 12.

In normal operation a fastener such as a nail, etc. will be placed in the open end of muzzle 15 with a flanged portion of the fastener resting on stop portion of muzzle l5 and with another portion of the fastener projecting further into the muzzle. Barrel 40 will be moved downwardly in barrel housing 12 as viewed in FIG. 4 or to a breech open position by throwing the barrel in a rapid downward motion until stop pin 41 abuts nut 50. Guide pin 48 will limit the travel of piston 45 in barrel 40. The spent cartridge in the barrel will be ejected as the breech is opened as hereinafter described. A blank cartridge is then placed in cartridge receiving opening 42 and the barrel is moved upwardly relative to barrel housing 12 until it is in the position seen in FIG. 5. As there is a great deal of friction between piston 45 and barrel 40, piston 45 will stay in the position seen in FIG. 4 relative to barrel 40 as the barrel is moved to the right relative to the barrel housing. Movement of barrel 40 upward relative to barrel housing 12 will cause ejector finger 53a to be moved by the rim of the cartridge thereby clamping the inside rim of the cartridge in cartridge receiving opening 42 in the manner illustrated in FIG. 9. The free end of muzzle 15 is now urged against the surface into which the fastener is to be fired as illustrated in FIG. 6. This causes the barrel to move in an abutting relationship with breech block 24 of barrel housing 12 pushing firing pin post 28 and firing pin plunger 29 to the right against the bias of spring 30 as illustrated in FIG. 6. Movement of the firing pin plunger to the right in chamber 18 will move sear pin 32 and hence firing pin upward and to the cocked position illustrated in FIG. 6. At this point trigger 37 can be depressed causing cam follower 32a on sear pin 32 to slide along cam portion 37b of the trigger depressing the sear pin and removing it from between

lands

21 and 22. With the sear pin 32 no longer holding the firing pin in the cocked position spring 17 moves the firing pin to the position seen in FIG. 7 so that the firing pin will abut the rim of the cartridge in the cartridge receiving chamber and fire the cartridge. Piston 45 as a result of this moves downward in the barrel 40 driving the fastener member by the impact of the fastener with the ported end of piston rod 46 into the material against which the muzzle has been pressed against. By having the free end of piston rod 46 ported 47, the weight of the piston rod is lessened at its impact end thus lessening the impact transmitted therefrom to the fastener and the impact felt by the piston rod. The port 47 at the free end of the piston rod also serves to trap air and control the velocity of the piston rod and with the lessened mass of the rod increase its service life. The bumper guard 200 also softens the impact of the piston or the muzzle.

Subsequent to the firing of the fastener the barrel is thrown downward in barrel housing 12 to the breech open position seen in FIG. 4 with the abutment of stop pin 41 after having moved between slotted extension 51 against adjusting nut 13 limiting this movement. The cartridge exhaust gases are vented through slot 44. As the barrel is thrown open ejector finger 53a retains a sufficient grip on the rim of the firing cartridge so that the cartridge is ejected from the cartridge opening 42. However, the momentum imparted to the cartridge by the movement of the barrel is sufficient to strip the cartridge from the barrel as illustrated in FIG. 4. Throwing the barrel open also causes the piston to move downwardly with the barrel with movement of the piston in the downward direction being halted by the abutment between guide pin 48 and the piston.

If it is desired to fire the tool and have the piston receive less impact force and hence transmit less impact force to the fastener member than with the tool as previously operated, adjusting nut 13 is rotated so as to move upwardly along barrel housing 12. Adjusting nut 13 can be precisely located along barrel housing 12 by moving it to a fixed location relative to guide lines 17. By moving nut 13 towards the breech block 24 of barrel housing 12 subsequent to the tool being fired and before the barrel is opened stop pin 41 does not abut nut 13 at the same position relative to the barrel housing when the barrel is moved to open the breech as was the case when the nut was in its previous position. Stop pin 41 now abuts the edge of the nut 13 nearer to the breech block of the barrel housing (FIG. 11) when the breech is opened. As a result of this piston 45 will not move to the uppermost portion of chamber 43 when the barrel is thrown open since the piston abuts guide pin 48 which is fixed relative to the barrel housing and does not move as the adjusting nut moves. The piston is now spaced the same distance from the uppermost portion of chamber 43 as the distance between the stop pin 41 and the lowermost portion of slotted extension 51. as illustrated in FIG. 11.

When the tool is cocked in the manner previously described piston 45 will maintain its position in barrel 40 as a result of the friction between the cylinder and piston and thus will not be in the uppermost portion of chamber 43 as viewed in FIG. 12. By having the piston spaced a distance from cartridge receiving opening 42 the impact of the cartridge will not be as great on the piston since there is a greater volume in which this impact may be dissipated. Similarly, the piston will have a shorter stroke since it has already been advanced towards the fastener which is loaded in muzzle l5 and thus the impact force from the cartridge will act on the piston and hence the fastener for a shorter period of time.

The adjusting nut provides accurate control for varying the amount of the force applied to the piston and hence to the fastener. This is achieved in a simple manner thus overcoming one of the drawbacks of prior art powder activated tools.

We claim:

1. An improved powder actuated tool for driving a fastener into a body, the tool having a barrel having a bore opening extending substantially therethrough, one end of the barrel having a breech opening in communication with the one end of the bore adjacent thereto and adapted to receive a propellant device, the other end of the barrel having a muzzle opening terminating in the other end of the bore, the barrel having a slot extending along a portion of the length of the barrel intermediate the ends thereof and through the wall of the barrel to the bore; a barrel housing for slidingly supporting the barrel for movement along the length thereof, the barrel housing having a cavity therein disposed adjacent the line of travel of the breech opening of the barrel for providing access to the breach opening when the barrel is moved in a forward direction extending .toward the muzzle opening to a loading and unloading position in which the end of the barrel. having the breech opening is substantially clear of the cavity, when the barrel is moved in a rearward direction to a firing position the breech opening being closed by being adjacent to a wall portion of the cavity; and apiston disposed in the bore of the barrel, the forward portion of the piston being adapted to strike a fastener disposed in the bore of the barrel adjacent the muzzle opening when the piston is propelled during firing in a forward direction in the bore, the driving energy applied to the piston being an inverse function of the distance of the piston from the breech opening at the time of firing; the improvement comprising:

means extending through the slot in the barrel for stopping the forward travel of the piston at a predetermined stopping position relative to the housing when the piston is moved in a forward direction into engagement with the stopping means in response to frictional engagement of the piston with the barrel as the barrel is moved towards the loading and unloading position; and

means mounted on the housing between the breech opening of the housing and the forward end of the housing and movable in the forward and the rearward directions for adjustably limiting the sliding of the barrel in the fonuard direction to a forward extreme position, the limiting means engaging a member fixedly mounted on the barrel to limit the sliding of the barrel to the forward extreme position as the barrel is moved in the forward direction, thus causing the piston when in engagement with the stopping means to be placed in a predetermined position relative to the breech opening of the barrel, whereby the relative position of the piston to the breech opening can be selected to thereby control the driving force to be applied to the piston.

2. The improved powder actuated tool of claim 1 in which the piston stopping means comprises a piston stop pin mounted on the barrel housing and extending into the bore of the barrel through the slot therein for abutment with a portion of the piston facing in the forward direction when the barrel is moved to the loading and unloading position.

3. The improved powder actuated tool of claim 2 in which the piston stop pin is mounted adjacent the muzzle end of the barrel housing.

4. The improved powder actuated tool of claim 1 in which the barrel limiting means comprises an adjusting nut threadedly mounted about the exterior surface of the barrel housing adjacent the forward end of the breech opening thereof for adjustable movement in the forward and the rearward directions in response to rotation thereof, the adjusting nut being adapted for a portion thereof facing in the rearward direction to abut the member fixedly mounted to the barrel end thereof the barrel stop pin extending through the cavity in the barrel housing for abutment with the rearward facing portion of the adjusting nut when the barrel is moved to the loading and unloading position, thereby adjustably limiting the sliding of the barrel in the forward direction.

l i II I I Patent No. 3,652,003 Dated March 28, 1972 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

5 Column line 37, "Cylinder" should; be vbarrel Column line 39, "cylinder" should be barrel Column line 40, after "barrel" insert housing line 38, ":Lert should be bottom Column 2, line #0, "cylinder" should be barrel Column 3,

Column line 22, insert U-shaped before "slot".

Column l, line 26, "cylindex should be barrel Column t, line &8, "cylinder" should be barrel in both instances.

Column L, line 56, delete 'to the" (first occurrence) Column 6, line 7, "cylinder" should be barrel Signed and sealed this 28th day of November 1972.

(SEAL) Attest:

EDWARD PLFLETCHER,JR, ROBERT GOTTSCHALK Attes ting Offi Commissionerof P2 tents F ORM PO-105O (10-69)

Claims

2. The improved powder actuated tool of claim 1 in which the piston stopping means comprises a piston stop pin mounted on the barrel housing and extending into the bore of the barrel through the slot therein for abutment with a portion of the piston facing in the forward direction when the barrel is moved to the loading and unloading position.
3. The improved powder actuated tool of claim 2 in which the piston stop pin is mounted adjacent the muzzle end of the barrel housing.
4. The improved powder actuated tool of claim 1 in which the barrel limiting means comprises an adjusting nut threadedly mounted about the exterior surface of the barrel housing adjacent the forward end of the breech opening thereof for adjustable movement in the forward and the rearward directions in response to rotation thereof, the adjusting nut being adapted for a portion thereof facing in the rearward direction to abut the member fixedly mounted to the barrel when the barrel is moved to the loading and unloading position, thus limiting the forward movement of the barrel to the forward extreme position.
5. The improved powder actuated tool of claim 4 in which the member fixedly mounted to the barrel comprises a barrel stop pin mounted to the barrel adjacent the breech opening end thereof, the barrel stop pin extending through the cavity in the barrel housing for abutment with the rearward facing portion of the adjusting nut when the barrel is moved to the loading and unloading position, thereby adjustably limiting the sliding of the barrel in the forward direction.