US3278106A - Firing control means - Google Patents

Description

S R D mma n 6 m l W 0 vHm m N C IIEI n m BU" A T 2, Mm 3 A A 6 0 C. T. BECHT ETAL FIRING CONTROL MEANS Filed April 15, 1965 Y W1 MAIL, m #im Oct. 11, 1966 United States Patent 3,278,106 FIRING CONTROL MEANS Carl T. Becht and James H. Racer, Cincinnati, Ohio, assignors to Senco Products, Inc., Cincinnati, Ohio, a corporation of Ohio Filed Apr. 15, 1965, Ser. No. 448,412 1 Claim. (Cl. 227-8) This invention relates to fastener applying devices, and more particularly to an improved firing control and safety means for pneumatically operated fastener applying devices.

In a conventional, pneumatic fastener applying device, compressed air from a suitable source of supply is admitted into a working cylinder to drive a piston or working member and its associated driver in a power stroke. A plurality of fasteners from a magazine or other source of supply are successively fed into position to be driven by the driver on its working stroke. Control of the admission of air into the working cylinder of the tool is achieved by a suitable firing control means, which, especially in the case of the larger tools, will take the form of a remote valve. As is well known in the art, the remote valve at the head of the working cylinder. The remote valve or other firing control means is normally actuated by means of a manual trigger under the control of the operator.

With particular but exemplary reference to stapling and nailing devices, technology is continually developing to permit the driving of larger and larger fasteners, this of course requiring more and more driving power in the tool itself. In addition, manufacturers and operators have become increasingly conscious of the possibility and desirability of increasing the speed of operation of such devices.

These two factors, along with various other conditions, have created a severe safety problem, and made it eX- tremely desirable to provide a simple and positive safety structure. In other words, it is obvious that a fastener applying device which develops enough power to drive a two inch fastener into hard wood, can certainly drive that fastener a considerable distance through the air with the resultant possibility of injury.

Similarly, in response to the demand for increased speed of operation, the prior art has developed fastener applying devices in which the firing control means is actuated by means of a touch-fire member. This touch-fire member extends slightly beyond the nose piece of the tool, so that simply placing the nose piece of the tool against a workpiece actuates the firing control means, and fires the tool. This construction permits an operator to drive a plurality of fasteners simply by placing the fastener applying device against the workpiece in the proper position. But, should the operator inadvertently permit the nose piece of the tool to come in contact with his body, a co-worker, or anything other than the proper workpiece, the tool will fire, with the resultant possibility of injury.

The prior art has also developed a number of safety devices which are in some respect similar to the above described touch-fire control. That is, the safety device includes a member projecting slightly beyond the nosepiece of the fastener applying device. The firing of the tool is controlled by a manually actuated trigger, which is so designed that it cannot be moved or actuated until, by placing the tool against a workpiece, the safety member has been actuated. A safety such as the one just described is entirely adequate from the standpoint of safety, but has been found in practice to materially cut down the rate of operation of the tool, inasmuch as this arrange- 3,278,106 Patented Oct. 11, 1966 "ice ment requires a series of operations which must be carried out in sequence in order to fire the tool.

Accordingly, it is a general object of this invention to provide a simple and positive safety mechanism which will not affect the maximum speed of operation of the tool with a skilled operator.

More specifically, it is a very important object of this invention to provide a fastener applying device which may be operated either by placing the nose piece of the device against the workpiece, or by means of a manual trigger.

Still a further object of the invention is the provision of a firing control means requiring concurrent actuation of two separate and independent actuating members, one of the actuating members being controlled manually by the operator of the device, while the other of the actuating members is controlled by placing the tool against a workpiece.

Another object of this invention is to provide such a firing control means wherein the two independent actuating members must concurrently be in the firing position to cause the tool to drive a fastener, and wherein operation of the actuating members may be effected in any order.

Still another object of the invention is the provision of a firing control means including a manually actuated member, and an independent actuating member controlled by placing the tool against a workpiece, wherein substantially greater movement is required of the workpiece responsive member than of the manually controlled memher. That is, particularly in the case of large tools, the fastener driver will project a short distance beyond the nose of the tool at the end of its working stroke. This will tend to lift the tool away from the workpiece, against its own weight and whatever force is applied by the operator. These last two noted factors obviously tend to return the tool to the workpiece, and can cause an acci dental re-cycling of the tool. Therefore, the instant invention contemplates the use of a short stroke remote control valve operated by two independent actuating members, the movement of the workpiece responsive actuating member being greater than the above describe-d rebound of the tool, and greater than the movement of the manually controlled member.

Keeping the above objects in mind along with such other advantages that will become apparent as this specification proceeds, the invention Will be described in terms of a pneumatic stapler; but it is to be understood that the following specific description is exemplary only, and that the invention is equally applicable to any and all fastener applying devices.

Reference will be made from time to time to the accompanying drawings, wherein similar reference numerals have been used to indicate like parts throughout the several views. In the drawings:

FIGURE 1 is a side elevational view, with parts broken away and parts in section showing all of the components in the initial or inoperative position;

FIGURE 2 is a view similar to FIGURE 1 showing the workpiece responsive actuating member moved to its firing position;

FIGURE 3 is a view similar to FIGURES l and 2 showing the trigger moved to its firing position; and

FIGURE 4 is a view similar to FIGURES 1-3 showing all of the components of the firing control means of this invention in the firing position.

As indicated earlier, this invention has great and particular utility in connection with pneumatic fastener applying devices. As is well known in the art, such devices include a working cyclinder which is normally closed by a suitable firing valve. The firing valve is in turn actuated by a remote control valve which is movable from an inoperative position to a firing position. Keeping the previously noted objects of this invention in mind, it is this remote control valve which must be moved from its inoperative position to its firing position to affect an operative cycle of the fastener applying device.

Briefly considered, this invention contemplates the use of a manually actuatable trigger which is pivotally mounted in the housing of the fastener applying device, and movable from an inoperative position to a firing position. A lever, described in more detail hereinafter, is pivotally connected at one end to a workpiece responsive trip member, the other end of the lever being slidably supported by the trigger. Both the trigger and the lever described above are movable from an inoperative position to a firing position; movement of the trigger is manually affected by the operator, While movement of the lever is brought about by placing the nose piece of the fastener applying device adjacent the workpiece into which a fastener is to 'be driven.

The components described above are so arranged that movement of both the trigger and the lever to their respective firing positions is necessary to move the remote control valve to its firing position. That is, movement of either the trigger or the lever to its respective firing position alone will not operate the tool.

Referring now to the drawings, the various figures show the instant invention as embodied in a portable pneumatic stapler. The details of construction of the stapler per se do not form a part of the instant invention, and hence will not be described in this application. Reference is made to recently issued U.S. Patent No. 3,170,487 wherein one embodiment of a readily available pneumatic stapler is described in detail.

The stapler shown in the drawings has a housing indicated generally at having a nose piece indicated at 11. Extending rearwardly from the body portion 10 is the handle 12, adapted to be grasped by an operator. Extending rearwardly from the nose piece 11 of the tool is a staple magazine 13 which again, is well known in the art and which serves to successively place a plurality of fasteners into the nose piece 11, in a position to be driven.

It will of course be understood that the housing 10 includes a working cylinder with its outer wall shown at 14, within which is a working piston, and its associated fastener driver.

The delivery of driving power to the working cylinder is controlled by the remote control valve indicated generally at 15. It will be understood that the details of the remote control valve do not form a part of this invention, and hence only the lower most portion of the valve stem has been shown. As seen in the drawings, the lower portion of the valve stem is enlarged as at 16, and is slidably received in the bore 17 in the lower portion of the housing. This portion 16 of the remote control valve is larger than any other portion thereof, so that air pressure in the reservoir 18 in the handle 12 will act upon the exposed shoulders 16a to normally basis this member toward its lower most or inoperative position seen in FIGURES 1, 2, and 4.

Pivotally mounted to the housing as at 19 is the manually actuated trigger 20. As will be seen from carefully examining the drawings, the trigger 20 is of U-shape in cross section, and is provided at one end with the generally upwardly extending arms 21. These arms engage the portion 22 of the housing, and serve as a stop to define the lower most or inoperative position of the trigger 20.

As is conventional in the art, the trigger 20 may be pivotally moved from the inoperative position shown in FIGURES 1 and 2, to the firing position shown in FIG- URES 3 and 4-. It will be noted that the tabs 23 on the trigger engage a position of the housing, and hence define an upper limit to movement of the manual trigger 20.

Disposed substantially within the trigger 2t) is the lever 24, which is curved as clearly shown in the drawings. One end of the lever is pivotally secured as at 25 to the upper most end of the arms 26, which in turn are fastened to the workpiece responsive trip member 27. The trip member 27 is slidable about the outside of the nose piece 11 of the tool, and in its lower most or inoperative position shown in FIGURES 1 and 3, extends a short distance beyond the end of the nose 11 of the tool. The free end of the lever 24 is slidable supported by the inner surface of the manually actuated trigger 20.

Operation of the foregoing arrangement will now be described.

In the position shown in FIGURE 1, all of the components are in the lower most or inoperative positions. That is, the remote control valve 15 is in its lower most position, the trigger 20 is in its lower most position with the arms 21 engaging the portion 22 of the housing, and the workpiece responsive trip member 27 extends a short distance beyond the end of the nose piece 11 of the tool.

In FIGURE 2, the fastener applying device of this invention has been placed adjacent a workpiece into which a fastener is to be driven. This moves the workpiece responsive trip member so that its lower most end is flush with the end of the nose 11 of the tool. As will be clearly apparent, this moves the pivot point 28 for the lever upwardly, and brings the inner surface of the lever 24 substantially into contact with the lower most end of the remote control valve 15. (The free end of the lever has changed its position in the trigger 20 very slightly.) It should be noted that by this motion, the position of the remote control valve stem 15 has not been changed.

Turning noW to FIGURE 4, it will be recognized that the workpiece responsive trip member and the lever 24 pivotally secured thereto have remained in the firing position, and that the manually actuatable trigger 20 has been pivoted to its firing position. As the manual trigger 20 is moved toward this position, it will force the lever 24 against the bottom portion of the remote control valve 15, raising this valve from its inoperative position to its firing position, thereby effecting at least the initiation of an operative cycle of the fastener applying device.

FIGURE 3 illustrates the relative positions of the various components when the manual trigger 20 is actuated prior to the device being placed adjacent a workpiece. In other words, the manual trigger 20 has been pivoted to its firing position. (This figure should be compared with FIGURE 2.) This is effective to move the lever 24 into a position closely adjacent the lower most end of the remote control valve 15, but is not effective to move the remote control valve 15 to its firing position. The fastener applying device may now be fired by simply placing it adjacent a workpiece, thereby moving the workpiece responsive trip member to the position shown in FIGURE 4, which moves the lever 24 upwardly, lifting the remote control valve to its firing position.

By comparing FIGURES 2 and 3, it will be seen that a substantially greater movement is required to bring the workpiece responsive trip member 27 (and associated lever 24) to its firing position than is required to bring the manual trigger to its firing position. As set forth earlier in this application, this expedient prevents accidential re-cycling of the tool due to the normal rebound after the working stroke.

It is believed that the foregoing constitutes a full and complete disclosure of this invention. By way of brief review, movement of each of two independent actuating members from their respective inoperative positions to their respective firing positions is necessary in order to fire the device. Movement of these actuating members to their respective firing position can be accomplished in any order.

Various changes and modifications may be made in this invention without departing from the scope and spirit thereof. Accordingly, no limitations are intended except insofar as set forth in the claim which follows.

The embodiment of the invention in which an exclusive property or privilege is claimed are defined as follows:

In a fastener applying device including a housing, a

pneumatic piston, a fastener driver associated with said piston, and means for successively feeding a plurality of fasteners into position to be driven by said driver, the improved control means comprising:

(a) means for controlling the delivery of driving power to said piston, said means being movable from an inoperative to a firing position;

(b) lever means arranged to contact and move said first mentioned means;

(c) workpiece responsive trip means movable from an inoperative to a firing position, said lever means being pivotally secured to said workpiece responsive trip means; and

(d) a manually actuated trigger pivotally mounted on said housing and engaging the free end of said lever means, said trigger being pivotally movable from an inoperative to a firing position, the distance between said inoperative position and said firing position of said workpiece responsive trip means being greater than the pivotal distance between said inoperative position and said firing position of said manually actuatable trigger, whereby movement of said means for controlling the delivery of driving power to said piston from said inoperative position to said firing position is effected only by movement of said trigger and said trip means to said respective firing positions.

References Cited by the Examiner UNITED STATES PATENTS 3,056,964 10/1962 Beckman et a1. 227--8 3,056,965 10/1962 Rogers 2278 3,162,097 12/ 1964 Allen et a1. 3,194,324 7/1965 Langas 227-8 X GRANVILLE Y. CUSTER, JR., Primary Examiner.

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