US3575332A

US3575332A - Barrel retention means for power-actuated tools

Info

Publication number: US3575332A
Application number: US733058A
Authority: US
Inventors: Lawrence J Brunelle
Original assignee: Olin Corp
Current assignee: Illinois Tool Works Inc
Priority date: 1968-05-29
Filing date: 1968-05-29
Publication date: 1971-04-20
Anticipated expiration: 1988-04-20
Also published as: FR1600607A; GB1216934A; CH480142A; DE1923050A1

Abstract

A power-actuated fastening tool having a housing in which a barrel is telescopically received for movement between a breechopen and a breech-closed position. At least one recess is provided on the barrel member into which a detent member, mounted on the housing, extends to releasably hold the barrel adjacent its breech-closed position.

Description

United StatesPatent Lawrence J. Brunelle East Haven, Conn.

May 29, 1968 Apr. 20, 1971 Olin Mathieson Chemical Corporation lnventor Appl. No. Filed Patented Assignee BARREL RETENTION MEANS FOR POWER- ACTUATED TOOLS sClaimgdDrawingFigs.

U.S.Cl. 227/10 lnt.Cl. B25cl/l4 FieldolSearch 227/10,11

References Cited UNITED STATES PATENTS 3,341,101 9/1967 Butler et al. 227/ 10x 3,468,465 9/ 1969 Mulno 227/10 3,469,757 9/1969 Kvavle et al. 227/10 Primary Examiner-Granville Y. Custer, Jr.

Att0rneysl-l. Samuel Kieser, William W. Jones, Richard S. Strickler, Robert H. Bachman, Donald R. Motsko and Thomas P. ODay ABSTRACT: A power-actuated fastening tool having a housing in which a barrel is telescopically received for movement between a breech-open and a breech-closed position. At least one recess is provided on the barrel member into which a detent member, mounted on the housing, extends to releasably hold the barrel adjacent its breech-closed position.

18L RETENTION MEANS FOR POWER-ACTUATED TOOLS This invention relates generally to improvements in tools for driving fasteners or the like into masonry, concrete, wood, steel and the like. More particularly, this invention relates to power-actuated tools of the type that utilize a reciprocating barrel member.

One type of power-actuated fastening tool in use today is that type which includes a barrel member which is telescopically mounted within a housing. The barrel member is moveable between a breech-closed firing position and a forward breech-open position wherein the cartridge chamber at the end of the barrel is exposed for the purpose of loading a fresh cartridge. However, when this type of tool is pointed in a downward direction with the barrel in a rearward position, the barrel will move from this position to its breech-open position. This characteristic is undesirable for several reasons. First, it requires the operator to manually return the barrel member to a rearward position which, over a long period of time, is both a time-consuming and a tiring operation. Secondly, if the barrel is placed against the work surface without being returned to a rearward position, due to the long relative movement between the barrel and the housing to move the barrel to its rearward position, the muule end of the barrel may move away from the desired location prior to the firing of the tool. Further, many tools of this type are provided with a mechanical extractor for the cartridge case which ejects the spent cartridge case when the barrel is moved from its rearward to its breech-open position. With tools that are so equipped, if the barrel moves forward relative to the housing prior to the fastening operation, a live cartridge will be extracted with potentially hazardous results.

In view of the above, it is an object of the present invention to provide a power-actuated tool wherein the barrel member is prevented from moving into its forward position when the tool is pointed in a downward direction.

It is another object of this invention to provide a tool wherein the accidental ejection of a live cartridge due to the barrel unintentionally moving forward relative to the housing is prevented.

These and other objects and advantages of the invention will become more readily apparent by reference to the following description of the preferred embodiment of this invention and to the accompanying drawings of which:

FIG. I is a transverse sectional view of a tool constructed in accordance with the present invention;

FIG. 2 is a transverse sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a partial top plan view of the tool showing the ejection port and the barrel in a rearward position; and

FIG. 4 is a partial side view of the tool taken in the vicinity of the ejection port.

Referring specifically to the drawings, FIG. I shows a tool constructed in accordance with the present invention having a housing 2 including a tubular forward portion 4 and a rearward portion 6. The tubular forward portion 4 includes an ejection port 8 which provides access for loading and unloading an explosive cartridge. The rearward portion 6 of the housing 2 houses the firing mechanism 10 and also includes a pistol grip l2 and a trigger guard 14.

The firing mechanism It) includes a breech face 16 having a frustoconical opening 18 therein. A firing pin 20 is mounted behind the breech face 16 for axial movement in the housing 2 and includes a frustoconical nose portion 22, a body portion 24 and a rearwardly extending rod portion 26. The firing pin 28 is urged forwardly by a suitable spring member 28. A detent member 30 extends radially downwardly from the body portion 24 of the firing pin 20. The detent member 30 is spring biased outwardly by suitable spring means 32.

A cocking rod 34 is mounted for reciprocation in the rearward portion 6 of the housing 2 and includes a forward portion 36 extending through the breech face 16 and into the tubular forward portion 4 of the housing 2. The cocking rod 34 may be spring biased forwardly by a suitable spring member 38. The cocking rod may also include an elongated opening 40 through which the detent member 38 on the firing pin may extend.

A trigger member 42 having a rear portion 44 may be pivotally mounted above the trigger guard 14 by a pivot pin 46. The trigger is resiliently urged away from the firing position by spring member 48.

A barrel assembly 50 is reciprocally mounted within the tubular portion 4 of the housing 2 and extends from the muzzle end thereof. The barrel assembly 50 includes a barrel member 52 having a bore 54 therein. The barrel member 52 includes a cartridge-receiving chamber 56 at its breech end for the reception of an explosive cartridge 58. The bottom outside surface of the barrel member includes an axially extending bottom portion 60 which is planar in a horizontal direction. An elongated slot 62 extends through said bottom portion 60. The barrel assembly 50 also includes a muzzle bushing 64 which has a bore 66 of lesser diameter than the bore in the barrel member 52 and is threadedly received 1 within the forward end of the barrel member 52. A sleeve member 68 surrounds the muzzle end of the barrel member 52 and includes an intumed flange 70 which is positioned between the forward edge 72 of the barrel member 52 and a shoulder 74 on the external surface of the sleeve 68.

A piston member 76 may be mounted for reciprocal movement within the barrel assembly 50. The piston member 76 includes a generally cylindrical head portion 78 and a reduced, elongated, cylindrical shank portion 80. A piston ring 82 may be mounted within a suitable groove 84 about the circumference of the head portion 78 of the piston member 76.

The muzzle bushing 64 is provided with a counterbore 86 in its rearward surface. A suitable buffer member 88 is mounted in the counterbore 86 to absorb the energy of the piston member 76 in the event that the piston member 76 is overdriven. In the preferred embodiment, the buffer member 88 comprises a hollow, cylindrical member fabricated from any suitable material such as polyurethane, nylon or other suitable elastomeric materials. The interior diameter of the buffer member 88 must be at least as great as the diameter of the bore 66 in the muzzle bushing 64, which in turn is of such a size as to slidably receive the shank portion of the piston member 76. The buffer member 88 extends rearwardly in the tool out of the counterbore 86 into the bore 54 of the barrel member 52 for a short distance.

-A barrel guide screw 90 is threadedly attached to the forward end of the housing 2 and includes a stem portion 92 which extends through the slot 62 in the barrel member 52 into the interior thereof. The stem portion 92 of the barrel guide screw 90, in addition to serving as a barrel guide and stop meansfor limiting the forward movement of the barrel assembly 50, also serves to return the piston member 76 to its firing position by means of engagement by the stem portion 92 with the forward surface of the head portion of the piston member 76 as the barrel assembly 50 is moved into its forward position.

If desired, the tool may be provided with an extractor 94 which includes a head 96 at one end having a lip portion 97 to engage the shoulder on the cartridge 58. The extractor is mounted in an axially extending bore 98 in the housing 2 and includes a spring member 100 which biases the extractor into a forward position. Means is also provided for biasing the extractor head 96 laterally inwardly from an outward to an inward position for cartridge case head shoulder engagement during movement of the barrel to the breech-closed position. This means takes the form of a spring 102 which biases a shoe 104 inwardly against the extractor with the spring 102 being backed up by a stop screw 106 connected to the housing member 2. The rearward portion of the extractor 94 is provided with a flange 108 which is adapted to abut a stop surface 110 in the bore 98.

The operation of the extractor 94 is such that as the barrel assembly 50 is moved into a rearward position, the inclined forward face of the head 96 of the extractor 94 will cam over the shoulder of the head of the cartridge 58 as it moves laterally outwardly against the bias of spring 102. When the barrel assembly 50 is in its rearward position, the head of the cartridge 58 will be positioned such that the lip portion of the extractor head 96 is in engagement with the shoulder of the cartridge 58. As the barrel assembly 50 is moved from its firing position toward a breech-open position, the spring 100 keeps the extractor head 96 against the bottom of the slot 111 in the rearward surface of the barrel member 52 until the flange 108 contacts the shoulder 110 in the bore 98. This prevents further extractor travel and both

springs

100 and 102 pivot the extractor 94 about the stop shoulder 110 and bias the head 96 more firmly to its inward position. As the cartridge case is pulled on only one side and is pushed inwardly by the extractor head 96, as the barrel member 52 moves forwardly from this point, the cartridge case will be pulled out of the cartridge-receiving chamber 56 and will tend to spin out of the ejection port 8 of the tool.

In operation, after a fastener is positioned in the munle bushing 64 and a cartridge 58 positioned in the cartridgereceiving chamber 56, the tool may be positioned against a suitable work surface. To fire the tool, the operator must push down on the housing 2 to move the housing 2 forward relative to the barrel assembly 50. In so doing, the cocking rod 34 abuts the rearward end of the barrel member 52 so that the housing 2 moves forward relative thereto. By virtue of the detent member 30 extending into the opening 40 of the cocking rod 34, the housing 2 also moves forwardly with respect to the firing pin until the forward face of the breech face 16 abuts the rear surface of the barrel assembly 50. At this point, the detent member 30 of the firing pin 20 is in operable alignment with the sear portion 44 of the trigger member, so that by pulling the trigger member 42, the sear portion 44 will release the detent member 30 from the opening 40 in the cocking rod and the firing pin 20 will move forward under the action of its spring member 28 until the nose portion 22 thereof ejects through the frustoconical opening 18 in the breech face 16 and actuates the cartridge 58. The gases generated by the explosion of the cartridge 58 will drive the piston member 76 forwardly and drive the fastener into the work surface.

Barrel retention means 112 are provided to prevent the barrel assembly 50 from moving forwardly from a point wherein the rearward end of the barrel member 52 is just about in a position to contact the cocking rod 34. This retaining means 112 includes a flat, springlike detent member 113 which is mounted in a suitable groove 114 in the external surface of the forward portion 4 of the housing 2. The detent member 113 is positioned at a point adjacent the rearward surface of the ejection port 8 and is generally in the form of a flat band spring fabricated from spring steel and bent into the appropriate configuration. The detent member 113 extends about the outside surface of the housing 2 and has its

end portions

115 and 116 turned inwardly toward each other over opposite sides of the ejection port 8 as shown in FIG. 2. The

end portions

115 and 116 extend inwardly to a point beyond the interior wall of the housing 2. As can be seen in FIG. 3, the

end portions

115 and 116 of the detent member 113 have their side comers slightly curved as indicated at 118.

The barrel member 52 includes two opposed recessed

portions

120 and 122. The rearward end of each of the recessed

portions

120 and 122 adjacent the end of the barrel member includes a tapered surface 124. In addition, the rearward end of the barrel member is chamfered as indicated at inherent resiliency of the detent member 113. Upon further rearward movement of the barrel member 52, the ends and 116 will move into a

corresponding recess

120 or 122 at a point immediately forward of the tapered surface 124. The engagement between the corners l 18 of the ends 1 15 and 116 of the detent member 113 and the tapered surface 124 at the end of each of the

recesses

120 and 122 in the barrel member 52 will hold the barrel member 52 in a rearward position. However, due to the inherent resiliency of the detent member 113, as well as the rounded comers 118 of the

ends

115 and 116 of the detent member 113 and the tapering surface 124 at the end of the recesses I20 and 122 in the barrel member 52, the operator will be able to move the barrel assembly 50 forwardly relative to the housing 2 by applying a slight force thereto after the firing operation.

While reference has been made above to a specific embodiment of this invention, various modifications and alterations will readily suggest themselves to those skilled in the art. Accordingly, the scope of this invention should be ascertained by reference to the following claims.

lclaim:

1. In a power-actuated tool, housing means, barrel means telescopically received within said housing means for movement between a breech-open and a breech-closed position, said barrel having at least two diametrically opposed recesses in its outer surface, said housing means having a circumferentially extending groove in its outer surface, a flat band spring mounted in said groove and having two end portions, one end portion being turned inwardly through an opening in said housing means into engagement with one of said recesses and the other of said end portions being turned inwardly through an opening in said housing means into engagement with the other of said recesses when said barrel means is positioned adjacent its breech-closed position to releaseably retain said barrel means from forward movement relative to said housing means.

2. The power-actuated tool of claim 1 wherein the rearward end of each of said recesses is tapered and each of said end portions of said spring member has rounded corners.

3. The power-actuated tool of claim 2 wherein said housing means includes an ejection port, said end portions being turned inwardly toward each other over opposite sides of said ejection port.

4. The power-actuated tool of claim 1 further including a cartridge-receiving chamber positioned at the breech end of said barrel means, and extractor means mounted in said housing means and operable to eject a cartridge case upon movement of said barrel means from its breech-closed to its breech-open position, said recesses and said spring member being positioned to releasably hold said barrel means from movement toward its breech-open position to prevent ejection of a cartridge case.

5. The power-actuated tool of claim 1 further including a cartridge-receiving chamber positioned at the breech end of said barrel means, firing pin means positioned in said housing means, cocking means for engagement by said barrel means during a portion of the movement of said barrel means into its breech-closed position to cock said firing pin means, said recesses and said spring member being positioned to releasably hold said barrel means from movement from a position just before it engages said cocking means to its breech-open position.