US2493640A - Staple driving machine - Google Patents

Description

Jan. 3, 1950 R. E. PETERSON 2,493,640-

STAPLE DRIVING MACHINE Filed March 21, 1947 Patented Jan. 3, 1950 PATENT OFFICE STAPLE DRIVING MACHINE Roy E. Peterson, Norwalk, Conn., assignor, by mesne assignments, to The E. H. Hotchkiss Company, Norwalk, Conn., a. corporation of Delaware Application March 21, 1947, Serial No. 736,195

11 Claims.

sion the spring, with an automatic release to ,5

release the driver for operation by the spring to drive the staple. This type of machine is sometimes called a tacker. In this type of machine as now generally constructed, the driver is connected to a reciprocal plunger having considl0 erable weight, which operates with the driver and through its momentum to impart a sort of hammer blow to the staple. This weight, however, slows up the action and speed of the driver,

and then after it has been gotten up to speed, 16

some means must be provided to arrest the movement of this relatively heavy plunger. These are objectionable features, and due to the reduced speed of the driver in the driving operation of the staple, there is a tendency for the staple to D.

buckle and not penetrate the work properly.

It is an object of the vpresent invention to eliminate this weight or plunger on the staple driver and operate the driver directly from the I have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In this drawing:

Fig. 1 is a. vertical longitudinal section through the device;

Fig. 2 is a horizontal section substantially on line 2-2 of Fig. 1;

Fig. 3 is a front view with the front plate removed, the plane of the figure being substantially on line 3-3 of Fig. 1;

` Fig. 4 is a detail vertical section substantially on line 4-4 of Fig. 1;

Fig. 5 is a detail section substantially on line 5--5 of Fig. 1;

Fig. 6 is a section of the upper portion of the device showing the operating lever and the releasable pawl at about the time it releases the staple driver;

Figs. '7 and 8 are inner and top views respecspring, so that it is operated at a much greater g5 tively of the guide plate at the front of the speed than is possible with the weighted driver, and there is less diiiiculty in arresting movement of the driver at the completion of the driving operation. It has been found that 'the staples are driven better with a higher speed, :30

well as increased speed. In short, with this de- 240 vice much greater speed of the staple driver is effected than where weight or momentum relied on, and as suggested, it has been found that increased speed gives better and more reliable setting of the staple.

It is also an object to provide an improved means for retracting the driver by action of the operating lever in placing the driver and tensioning the spring for the driving operation.` v

A greater speed also reduces buck- 85 feed guide, and

Fig. 9 is a side elevation of the front end portion of the housing with the front plate removed but shown in dotted lines.

The machine as illustrated comprises a housing I II including a pair of side plates II, preferably stamped to form of sheet metal and enclosing an inner housing I2 of generally U-shaped cross section, comprising side members I3 at the inner side of the side members II, and a front guide wall I4 connecting these side members I3. This front guide wall has vertical slots I5 and I6 for certain of the operating members, as will be later described. The side plates I I have their upper edges turned inwardly to form the top of a hand grip as indicated at I'I, and has an elongated slot I8, the edges of which are similarly turned in as shown at I9, forming iianges which provide the lower part of the hand grip. Y

Mounted in the lower part of the housing between the side members l I is a staple guide bar 20 extending longitudinally of the machine. This is preferably substantially U-shaped in cross section, as shown in Fig. 4, for lightness and also to With the foregoing and other objects in vieW.- 50 permit its being formed of a strip of sheet metal.

bar 2U. Thus, should astaple become jammed in the lower end of the racewayor guide for the staple driver, plate or block 6U may be readily removed to permit removal of the jammed staple.

Means is provided for feeding the staples along the bar 20 to bring them successively tothe driving position in the guide or raceway 30 under the staple driver 3|. This comprises a substantially U-shaped follower 10 resting on the top of the bar 20 and engaging the rear end of the staple strip 1| to feed it forwardly along the bar. It is fed forwardly by means of a coil spring 12 embracing a guide rod 13 slidably secured at its forward end to the follower 10 by any suitable means, such as the loop 14 secured to the top wall of the follower. The inner end of the rod is enlarged or headed at 13a to prevent the follower being slid off the rod by the spring. The other end of this rod is connected at 15 to the end wall 16 of a block 11 of inverted U-shape in cross section, preferably formed from sheet metal, and carrying on the underside of its top wall a spring catch 18 carrying an upwardly projecting lug 19 adapted to seat in an opening 80 in the top wall of the insert member 39, the forward end 8| of the spring being curved downwardly so as to have a camming action on the end of the top wall of member 39 to force it downwardly when the block 11 is inserted in the end of the member 25. The push button 82 carried by this spring 18 projects through an opening in the top of the member 11 for depression of the spring 18 to release the catch 19. Adjacent this forward end the follower 1|) may have a downwardly extending lug 83 lanced and bent downwardly from its top wall to engage vthe front cross wall 84 at the end of the staple guide 20 to limit forward movement of the follower when the last staple has been driven and prevent the end of the follower moving into a position under the staple driver 3 I In operation the parts are normally substantially in the position of Fig 1. Depression of the lever 35 downwardly or to the right, as indicated by the arrow 85, will through the action of the pawl 34 raise the staple driver 3| to substantially the position of Fig. 6, carrying with it the spring rod 32 to substantially the dotted line position of Fig. 1. This will tension the spring 32 and will raise the lower end portion of the driver 3| from its position in front of the staple guide bar 20, permitting the forward staple 1|a to move into the lower end portion of the guide and raceway 3U under the lower end of the driver 3| and into the driving position. As the lever 35 approaches its lower position carrying the pawl 34 to its upper position, as shown in Fig, 6, the stationary member 5l! engages the cam surface 49 and shifts the pawl to the right, withdrawing its end 33 from the opening 31 in the staple driver 3| and from the shoulder at the top of this opening. This releases the driver 3|, permitting the spring rod 32 to operate it downwardly to drive the staple. Downward movement of the driver 3| and rod 32 will be arrested by the resilient bumper and stop 4|. Release of the handle 35 will permit it to be swung backwardly to the normal position of Fig. l by action of the spring 53. This will carry pawl 34 downwardly until its forward end 33 again snaps into the opening 31 in the driver preparatory to the next operation.

It is to be especially noted that the spring 3'2 is connected directly to the staple driver 3|, and that this driver comprises only the elongated nat steel strip, and that there is no weight or plunger or any other element connected to this driver to add weight to it and add momentum for a hammer blow, as is common with present types of machines of this character. Therefore, the Vweight of the driver and its inertia or momentum is reduced to a minimum as there is very little weight to the flat strip 3|, Therefore, this driver is operated with much greater speed than is possible with the old type of driver, which includes a weighted plunger or similar carrying device for the driver, the inertia of such a device greatly slowing up the speed of operation of the driver, and the momentum or weight of the plunger or carrier for the driver is relied on to give a hammer blow to the staple to drive it at the end of the driving operation. With such a device a heavy spring is required and the speed of driving the staple is very much slower than in the present device, and the weight or momentum of the carrier or plunger for the driver is relied on to a large extent to drive the staple and secure the necessary penetration of the prongs of the staple. In the present construction, because of the minimum weight and momentum of the driver 3|, there is no blow or momentum of the weighted element relied on, but a greatly increased speed of operation of the driver and driving action of the staple is secured over the old devices, this speed of operation securing better penetration of the prongs of the staple and, due to this much greater speed of the driving action and therefore the much greater speed of the penetration of the prong, there is much less danger of the prongs folding or buckling during the driving operation, as they do not have time to buckle as they do in the old type of device. It has been found that speed is more important than weight or'momentum in properly and effectively driving the staples. This arrangement also simplifies the construction Iand tends to 'lightness or less weight. Also, as a lighter operating spring may be used, it is much more easily operated and less pressure is required in depressing the operating lever preparatory to the staple driving operation. Operation of this device is, therefore, much less tiring on the operator, and it may be used continuously much longer without fatigue.

'I'he driver retracting and release construction comprising theA bodily slidable pawl 34 is also a material improvement over the old type of construction involving merely a pivoted pawl depending on a runout of this pivoted pawl for the release. In this case a more substantial support is provided by the pawl, and as there is a positive shifting of the pawl for the release by means of the stop 50 and the cam 49, and therefore a positive release at a certain time, the release can be more accurately and reliably controlled, insuring that the driver is not released until it is retracted to the proper position.

In loadingmore staples into the machine, it is merely necessary to release the catch 19 by depressing. the button 82 and withdrawing the block 11 and the follower 10. After the new staple strip is inserted on the guide bar 20 the follower is also inserted from the rear end onto this bar and the block 11 moved inwardly until caught by the catch 19, thus compressing the feed spring 12 and tensioning it so it may feed the staples forwardly.

Should for any reason a staple become jammed under the driver 3| in the lower part of theraceway 30, the spring strip 65 may be swung laterally to releaserrthe plate orblock 60, which may then be. removed to permit the jammed staple to drop out.v Y .i i.

i ".Havin'g. thusv set forth the nature'of myinvention, what I'claim is:`

I. A staple driving; lmachine comprising a guide bar for a strip of staples, a substantially -flat staple driver mounted nfoi'.. reciprocating .movement across the front end of the guide 'bar to drive .the individual staples in succession, a Vspring comprising arod fastened at one end and ai; the other directly engaging the driver forf operating -it to drive the staples, a Ypivoted operating lever, and a releasable'pawl carried Ybythe lever normally engaging the driver to retractit totenrsiontlie spring and thenfrelease'the driver yfor the driving operation.

2. A staple driving vmachine comprising a. guide bar for a staple strip, a staple driver mounted for `movement across the end of the'bar to drive a staple, means for. feeding the staples along the bar to driving position, a spring rod fastened at one end and ateits other end engaging a shoulder Y.on the driver to operate it, a pivoted operating a staple comprising a substantially flat' elongated strip, Vmeans for feeding staples along'the bar to driving position, a spring rod .fastenedk at one end and at its other jend engaging a shoulder on the driver to operate` it, a pivoted operating lever, a releasable paivl on the lever engaging a shoulder on the driver to retract the driver to tension the spring and then release the driver for` the staple driving operation, and a resilient bumper under the spring to limit forward movement of the spring; n

4. A staple driving machine comprising a guide bar for a strip of staples, a driver' consisting of a light Weight substantially at elongated strip Vmounted for movement across the end ofthe bar to drive a staple, means for feeding staples along the bar to driving position, a spring comprising a rod fastened at one end and at: the other directly engaging the driver strip to operate it, an operating lever, andV a'releasable pawl on the lever engaging the driver strip to retract it 'to'tension the spring and then release the driver strip for the driving operation. 5. il ple driving machine comprising a guide bar for a strip-of staples, a driver' consisting of alight weight substantially flat elongated strip of substantially the samethickness-throughout .mounted for movement across the end'of the'bar todrive a staple, said strip being provided with verticallyrspaced shoulders, aY spring' comprising a rod fastened at 'one end and engagingonefof y.said shoulders at the other lend tooperate'the driver ton drive a staple, an operating lever, Yand a releasable patvlonthe lever engaging the other Yshoulder to retractthedriver and tension the spring and then .release the driver for the driving Y:operation: Y i. 1

6.' A staple driving machine comprising La guide bar for astrip of staples,'a driver consisting of a substantially flat Aelongated strip mounted for movement across the end of the' bar Ato drive a staple, said strip being provided vvitlrspaced Y Vto operate the drivenan operating lever, and a rei8 leasable pawl on the lever engagingthe Iother shoulder to retract the driver to tension' the spring and then release said driver for the driving operation;

7. A staple drivingV machine comprising a guide bar for a strip of staples, a driver consistingy of a substantially flat elongated strip mounted for movement across'the end of the bar to drive a staple, said strip being provided with spaced shoulders, a spring rod fastened at one end and at the other end engaging one of said shoulders to operate the driverymeans engaging the other shoulder to retract the driver to tension the spring and then release said driver for the driving operation, and a resilient bumper under the spring rod to limit the driving movement.

8. A staple driving machine comprising a guide bar for a staple strip, a staple driver mounted for movement across the end of the bar to-d'rive a staple, means for feeding the staples along the bar to driving position, a spring engaging the driver for operating it, an operatinglever, a'pawl onrthe lever engaging a shoulder on the driver to retract it to tension the spring, cooperating guide means on the pawl and lever'mounting the paivl for bodily slidingmovement on4 the lever Vforwardly toward and rearwardly from the shoulder, a spring tending to shift the pawl` toward the shoulder, and cooperating cam means to shift the pawl bacliwardly from said shoulder to release the `driver as it approaches its retracted position.

9. A staple driving machine comprising a guide bar for a staple strip, a staple driver Ymounted for movement across the end oi the bar to Ydrive a staple, means for feeding the staples along the bar to driving position, a spring `engaging the driver for operating it, a shoulder'on the driver, on operating lever, a releasable pavvl engaging said shoulder andY mounted Von ther lever' for bodily sliding movement toward and from the shoulder, said Vpawl being adapted to retract the driver to tension the spring by operation of the lever, a spring tending to hold the pawl in engagement with the shoulder, a camsurface on' the pavvl, and a stationary member positioned to engage the cam ,tov shift the pavvl from the shoulder to release the driveras itv approaches the retracted position.

10. A staple driving machineY comprising a guide bar for a staple strip, a 4staple driver mounted for movement across the end of the bar to drive a staple, means for feeding the staples along the bar to driving position, a spring engaging the driver for operating it, yan operating lever, a pawl engaging a shoulder on the driver to retract the driver and tension the spring by operation oi' thai-ever, said pavvl being provided with an elongated slot, spaced pins' in the lever passing through the 'slot' to mount the pawl for sliding movement toward and from theshoulder, a spring tending to shift the pawl to engage said shoulder', a can; surface on Ythe pavvl, anda stationary member positioned to'engagesaid cam surfaceV to shift the'pawl `to release rthe driver as it approaches its retractedposition.-

' 11. A- staple V:driving machine comprising a guide bar for a-V staple-strip, a staple-driver mounted for movement across the end of the bar to drive a staple, means ior feeding the staples along the bar; to driving position, a Yspring engaging the driver for operating it, an-operating lever including a pair VofY laterally;V spaced arms, a pawl mounted between said armsand engag- Yinsa ShQulder en, the .driver i0 'retract the driver ROY E. PETERSON.

REFERENCES CITED The following references are of record in the le of tlhis patent:

Number UNITED STATES PATENTS Name Date Posnack Jan. 30, 1934 Case Apr. 2, 1935 Hansen Sept. 22, 1936 Krantz Feb. 9, 1943 Polzer Mar. 23, 1943 Heller June 13, 1944 Lang Oct. 31, 1944

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