US2412620A

US2412620A - Tacker

Info

Publication number: US2412620A
Application number: US485044A
Authority: US
Inventors: Calvin P Kipp
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-04-29
Filing date: 1943-04-29
Publication date: 1946-12-17
Anticipated expiration: 1963-12-17
Also published as: GB576311A

Description

Dec. 17, 1946. P 2,412,620

TACKER' Filed April 29, 1943 4 Sheets-sh t 1 I" III" I l ATTORNEY DE? 17, 1948. c, p 2,412,620

TACKER Filed April 29, 1943 4 Sheets-Sheet 2 lllllllllll' j 5&60

INVENTOI'R 7 ATTORNEY Dec. 17,1946. c. P. KIPP Q 2,412,620 I TACKER Filed April ,29, 1945 4 shegts-shet 4 NVENTOR ATTORNEY Patented Dec. 17, 1946 UNITED STATES PATENT OFFICE 29 Claims.

The present invention is concerned with stapling r tacking devices and especially is directed to a staple tacker for securing a member such as cardboard, paper, cloth or the like onto a suitable material which may vary in resistance, for example, the material may be of wood, composition or press board, and/or the like relatively soft or hard in structure or vary in resistance between soft and hard. In tackers of the prior art, one of the chief problems is to provide a suitable stapling machine for properly tacking into grades of materials of varying resistances without either spoiling the material or fracturing the frame of the tacking machine or the operating parts thereof. As is well known tacking machines of the type alluded to do not employ an external staple clinching anvil and hence the staple driving blade of the staple driving means or ram thus must be projected out of the tacking machine to drive the staple into the material to be stapled. Where the material is soft, it offers small resistance and the staple may be over driven into the material and thus spoil the latter due to an excessive projection of the driving blade out of the tacker. rial is relatively hard appreciable resistance is offered to the driving blade and consequently the driven staple will be ineifectively tacked due to an inadequate projection of the driving blade. In practice it has been extremely difficult to regulate the proper impact of the blade of the staple driving means against the driven staple for effective tacking. Usually retarding means to interrupt the momentum of the ram was resorted to in the attempt to solve the problem. Such retarding means usually took the form of impact absorbing devices such as leather or rubber washers or shock absorbing springs. However even though such shock absorbing devices and Washers were resorted to fracture of the frame of the tacker or operating parts thereof would at times ensue. Where the shock absorbing devices characterized relatively stiff helical spring means another difficulty arose due to the uncontrollable tolerances in the lengths thereof and although such tolerances are fairly small, nevertheless in practice they have proved adequately great as a vitally serious cause for fracture of some parts of the tacker. One problem to be overcome therefore was to eliminate over projection of the driving blade out of the tacker and at the same time overcome the disturbed conditions caused by the sudden impact of the ram during its staple driving stroke and without however causing fracture of any parts of the tacker and without however In case the matebeing dependent upon the uncontrollable variations' in length of the shock absorbing or cushioning means in taking up the impact of the ram. By the present invention these difficulties have been overcome in the matter of controlling the projection of the driving blade out of the tacker during tacking operations irrespective of the grade of resistance of the material into which the staple is driven and irrespective of even variations in length of the shock absorbing spring means due to uncontrollable tolerances. Thus an object of the invention is to provide a novel and serviceable staple tacker having means for controlling the projection of the staple driving blade out of the tacker even though the ejected staple be driven into various resistant grades of materials. Another object of the invention is to provide means to prevent shattering of parts of the tacker in the utilization of multiple shock or impact absorbing means in the matter of effectively interrupting the momentum of the ram or staple driving means several times during its staple driving stroke. The invention further contemplates as an object the provision of bumper means for absorbing the residual momentum of the ram following successive interruptions thereof during its staple driving stroke. Further objects are concerned with a slidable plunger for impacting a fixed anvil against the resistance of a com-'- pressed spring prevented against solid compression by float means acting as a successive interrupter for slowing down the velocity of the ram towards the termination of the staple driving stroke in conjunction with an impact distributing member acting against an elastic or resilient deformable bumper confined in the ram for absorbing the residual velocity thereof. Other objects, aspects, and functional and structural features of the invention will appear from the following detailed description considered in connection with the accompanying drawings wherein:

Fig. 1 is a perspective view of the tacker or stapling machine according to my invention, illustrating the swingable cover closed.

Fig. 2 is a perspective View of the tacker showing the pivoted cover or hood partly opened.

Fig. 3 is a longitudinal sectional view in elevation of Fig. 1.

Fig. 4 is a fragmentary view of Fig. 3 showing the handle for operating the ram or driver depressed and the ram moving towards the completion of its upward stroke with the slidable plunger of the ram appreciably spaced from the fixed impact receiving anvil or abutment carried by the sides of the cover.

Fig. 5 illustrates the slidable ram receiving its first interruption on its downward stroke at a time when the slidable plunger has just struck the fixed impact receiving anvil or transverse stop at which time the staple driving blade of the slidable ram is flush with the lower end of the magazine.

Fig. 6 is a view similar to Fig. 5 but with the ram at its successive interruption at which time the retained float impacts th impact distributing member for compressing the hollow rubber bumper.

Fig. 7 illustrates the ram towards the com pletion of the downward stroke at which time the bumper is compressed.

Fig. 8 is an exploded perspective view of the ram or staple driving means.

Fig. 9 is a sectional view on the line 9-9 of Fig. 4.

Fig. 10 is a sectional view on the line Ill-l0 of Fig. 4.

Fig. 11 is a vertical but transverse sectional view of the frame of the cover on the line I l-H of Fig. 4.

Fig. 12 is a sectional View on the line |2l2 of Fig. 4.

Fig. 13 is a perspective View of the tacker illustrating the cover swung rearwardly beyond ninety degrees relative to the open top magazine at which time the staple follower is at th rear of the magazine.

Fig. 14 is a perspective and exploded view of the forward part of the tacker and particularly of the telescopic and fixed guide in the rail to prevent buckling of a driven staple as it is passing through the staple raceway or guideway, and

Fig. 15 is an enlarged sectional view on the lin [5-45 of Fig. 5.

According to the invention, the staple driving means or ram, broadly denoted D, is appropriately slidably guided in the sheet metal U shaped sheath S of th swingable hollow cover C having its sheet metal case or hollow rear part R pivoted on the slidable fulcrum pin P carried by the staple magazine M straddling and telescopically receiving the sides 9 of the case R.

Lever or arm I!) for raising the ram is pivoted on the fixed fulcrum pin II which secures the sides 9 of the case B and the spaced sides 8 of the sheath S of the cover together.

Pivotally mounted on fulcrum pin l2 carried by the pivoted lever or arm I0 is the pawl l3 having its stops I l normally held against the sides of arm in by spring l5 having its forward end abutting the forward end 25 of the pawl as shown in Fig. 3, its intermediate portion I6 is coiled about fulcrum pin l2 and its rear portion I1 anchored to the lever I9.

Normally lever I0 is held in a raised position by reason of the spring I8 having its upper end l9 continuously abutting the upper end of lever Ill, its intermediate portion 19 is wound about the transverse fulcrum pin H and its lower leg 19" is anchored to the case R of the cover.

The outside manipulatable handle H for operating lever in downwardly is pivoted on fulcrum pin 29 traversing the sheath S and is straddled by and bodily carries the hollow protective guard G having its sides 2| fixedly secured to the operating lever handle H by rivets 22 and rotatably sustained on the fulcrum pin 29-.

The inside lever or arm l0 carries the antifriction roller 23 held near the operating handle H and when the latter is depressed lever IQ is .4 pivotally depressed due to the thrust imparted to the roller.

Where the handle H is depressed and manual pressure is removed therefrom, spring I8 automatically raise lever l0, hence roller 23 automatically raises the pivoted handle H thus causing the hollow and depressed guard to straddle the upper part of the case as in Fig. 1.

Normally the forward lip 25 of the pivoted and spring controlled pawl I3 is within recess 26 (Fig. 3) of the ram or staple driving means D which is slidably guided in the U shaped sheath 8 and particularly between the front wall I and sides 8 of the sheath and the spaced rectilinear faces 28 of the spaced sides 9 of case B, the ram including the hollow rectangularly shaped body 29 embodying the aforementioned recess 26 and having fixed thereto the staple driving blade 36 and having the vertically arranged cylindrical bore 3! in which is inserted the hollow and cylindrical rubber bumper or cushion 32, the impact distributing metal disc the helicoidal shock absorbing or cushion spring 3 5, the impact applying slidable cylindrical plunger 35, and the cylindrical metal float or pin 60.

The plunger is slidably guided in bore 31 and is limited in its rectilinear downward displacement by a pin 36 fixed in any appropriate fashion to the staple driving blade and the body 29 of the ram and projects through the guide opening or slot 37 of the plunger 35 movably guided in bore 3|.

By the present arrangement the shock absorbing spring 34 is held adequately compressed but not closed in the bore of the ram to normally position the slidable plunger 35 against the stop pin 36 and the disc 33 against the rubber cushion 32.

A helicoidal power spring 38 confined Within the sheath S and the laminated head therefor characterized by the juxtapositioned plates 39 held together by rivets 39' and anchored to the sheath S by rivet 40 and fulcrum pin 20, normally holds the ram depressed (Fig. 3) at which time slidable plunger 35 which in part projects from the body of the ram is yieldingly against the fixed impact receiving anvil or abutment plate or stop 4! extending transversely of the sheath and appropriately fixedly anchored to the sides 8 thereof.

Within the magazine M is a fixed staple rail 42 for slidably supporting staples 43 which are urged towards a staple raceway or guideway 44 in alinement with the driving blade 30 of the ram by a slidable staple channel-shaped follower 45 to which is fastened one leg 46 of a helicoidal extension spring 4'! looped over an anti-friction grooved roller 48 and having its upper leg 49 positioned in a grooved guide 50 and extended upwardly and forwardly to be anchored to book 52 struck inwardly of the case R of the cover.

By reason of the fact that the cover is pivoted to the magazine, the cover may be swung away from the magazine to assume an angle beyond ninety degrees therewith until the rear end 52 of the curved rear top of the case R strikes the rear end or stop 53 of the straddling saddle 54 slidable transversely of the case since the upstanding sides 54 of the saddle are secured to the slidable fulcrum pin P. During rearward swinging movement of the cover staple follower 55 slides rearwardly due to the action of spring 4! until it reaches stop 55 or the rear wall (Fig. 3) of the magazine. Thus full access may be had to the rail except that portion thereof under the follower which is prevented from upward displacement by the inwardly turned lugs 56 of the follower moving in the retaining slots 51 between the rail and the magazine. In closing of the cover, the follower automatically moves forwardly by reason of spring 41 to urge the foremost stable to enter the raceway or guideway under the driving blade 39 as is well understood.

In Fig. 3, the tacker is closed and the blade 30 of the staple driving means D is substantially flush with the bottom wall of the magazine at which time the slidable plunger 35 is seated on the fixed transverse metal stop or abutment bridge 4| and the power spring 38 holds the metal slidable plunger 35 yieldingly against the stop. Thus the staple driver or driving means is held normally depressed by the expanded power spring 38 which becomes contracted as the driver or ram D is drawn upwardly by pawl l3 when handle H is depressed. It should be realized that the power spring 38 is of less stiffness than the helicoidal shock absorbing or cushion spring 34 which is confined in the slidable driver for normally urging the slidable plunger 35 downwardly.

Where a relatively stiff cushion or shock'absorbing spring is utilizedcertain problems arise due to uncontrollable irregularities in the free length of this spring. and such problems arise even due to small tolerances of plus or minus one thirty-second of an inch. Such positive or negative variations caused in actual practice a possible total variation of one sixteenth of an inch in linear deflection of the cushion spring. Since the linear working deflection of the cushion spring relied on is also approximately to the order of one sixteenth of an inch, this would result in approximately one hundred percent variation in linear working deflection of this spring since as previously stated approximately one sixteenth of an inch 01' less in linear defiection of this cushion spring is relied on in actual practice. Therefore where the tolerance is negative, practically no linear working deflection is available and this would in some instances cause the cushion spring to compress solid in that it is now slightly weaker, thus transferring the full impact of the plunger on the transverse anvil or abutment stop 4| which impact in turn was transferred to the metal sheath of the tacker frame resulting in either fracture of the sheath or the fracture of the compression spring itself.

In case where the linear deflection became relatively great, due to an uncontrollable positive tolerance, this spring although prevented from solid compression was proportionately but undesirably stiffer ofiering needlessly greater re sistance, thus providing less cushioning or absorptive effect, and in practice such type of stiffer spring would snap or fracture upon impact of the plunger against the fixed anvil or in some instances would result in the fracture of the frame of the tacker, that is, either the sheath and/ or case thereof.

Consequently variations in linear deflection due to even small plus or minus tolerances of the cushion spring are thus an important factor in the matter of providing an effective operating tacking machine since direct cause for fracture was traceable to such uncontrolled tolerances. To overcome such factors in adequately absorbing the impact of the plunger against the fixed anvil or stop bridgin the sides of the sheath,

ill)

it has been discovered that the staple driving means or ram in its down stroke musthave its velocity successively interrupted to slow it down appreciably before bringing the staple driving means to a sudden and final stop which takes place only when the staple has been fully driven into the material to be stapled. By such action the blade of the staple driving means would not be projected in excess of the desired and relatively slight blade extension beyond the raceway in effectively driving the staple into the material.

With the present construction even though a relatively stiffer power spring is employed, thus obtaining a much greater impact of the plunger against the anvil, it is possible to cushion this blow in utilizing a relatively weaker or softer cushion or shock absorbing spring. The present ratio of maximum loads being substantially thirtyone pounds for the shock absorbing spring to forty pounds for the power spring whereas hitherto such ratio was substantially forty-two pounds for the cushion spring to thirty-two pounds for the power spring.

Hence according to the present invention a relatively stiffer power spring is utilized, but which is relatively greater in stiffness than the cushion spring 34 substantially in ratio above outlined and although a relatively softer cushion spring be employed efiectiveness of such spring is independent of its tolerances since means is provided to prevent solid compression thereof, and lastly the final impact of the ram 01'. staple driving means on its down stroke following prior interruptions of the ram is taken care of or absorbed by supplementary cushioning means in the form of an impact distributing member and the resilient bumper of adequate wall thickness or depth and this bumper becomes deformed at this time and during this action the staple driving blade is projected further out of the magazine to completely drive the staple into the desired material. In this connection it will be observed that the cylindrical pin or float 66 is mounted within the cushion or shock absorbing spring 3% and is positioned by the latter although it is of a length less than this spring (Figs. 3 and 5). By such arrangement although the cushion, spring is at all times partially compressed and becomes further compressed on the down stroke of the ram, it never will be compressed solid, namely, to permit its superimposed convolutions to contact one another, in that the float serves as means to prevent total or solid compression.

Again assuming that the driver is at the top of its stroke (Fig. 4) and the pivotal pawl [3 has just tripped, the power spring expands and im-,

parts a velocity to the ram or staple driving means, thus moving the latter downwardly. This velocity increases until interrupted by the impact of the slidable plunger 35 on the fixed transverse metal stop or anvil 4! secured to the sides 8 of the sheath. In this case it is assumed that the ram is operating idly and the tacker is empty of staples. At the instant of such impact or first interruption of the ram to slow it down the lower end of the driving blade is approximately flush with the bottom wall of the magazine.

Pursuant to this first interruption of the ram, the latter although slowed down, nevertheless, continues to move downwardly due to its momentum or inertia. Thus two factors now exist: one, the lower end of the blade 30 is progressively projected out of the magazine, and two, the slidable plunger is moved relatively inwardly of .the ram D to compress the cushion spring 34'but not solid in that the float or pin 60 has struck the impact receiving and distributing metal disc or diaphragm 33, or in other words the ram receives its second interruption (Fig. 6) in which instant the cushion spring is prevented from further compression although the blade is slightly extended about one sixty-fourth of an inch beyond the magazine but insufficiently projecting to complete driving of the staple into the material. Although the ram has received its second interruption upon coaction of the float 6!! against the impact distributing disc 33 and is almost abruptly stopped, nevertheless it still has residual momentum, thus continuing its downward stroke until its velocity is substantially zero, consequently the lower end of the blade is further projected (Fig. 7) out of the magazine and by such projection the staple formerly in the raceway is completely driven into the material. However it is important to realize that following second interruption and during the exhaust of the residual momentum of.the ram the impact on the slidably guided disc 33 is transmitted to the hollow and cylindrical rubber or resilient bumper 32 causing the latter to become slightlyattenuated that is, thinner as to height and deformed (Fig. 7) and upon exhaustion of the residual momentum of the ram the staple ejected is completely driven into the material, the velocity of the rain is almost zero, the bumper is under compression and attenuated that is, thinner as to height, the compression spring is under greater compression than normal although not solidly compressed due to the interrupting control of the impact applying pin or float 6D, and the slidable plunger 35 has reached substantially the limit of its inward stroke into the ram (Fig. 7) at which time the blade extension is substantially maximum to the order of approximately one thirty-second of an inch. By this action the driving blade is prevented from protruding an undue amount beyond the magazine, first by interrupting the ram by the coaction of the slidable plunger and the fixed abutment, and secondly, by the combined total compression of the cushion spring and bumper taking into consideration of course that maximum blade extension varies in accordance with the strength of the power spring, if the staple driving means is idly operated and where it is not idly operated varies in accordance with this power spring and the resistance of the material into which the staple is driven.

Since the staple has been completely driven into the material as desired, shock absorbing or cushion spring 34 and rubber bumper now recoil or expand, thus automatically raising the ram against the resistance of the power spring 38, hence appreciably projecting the slidable plunger 35 out of the ram. During this time the blade of the driving means is again drawn upwardly to be substantially fiush with the lower wall of the magazine and during such upward movement the rain again becomes interlocked with the pivoted pawl H! as shown in Fig. 3.

Where a staple is driven out of the magazine for tacking, the ram during its downward movement is slightly interrupted when the blade starts to drive the ejected staple into the material into which the staple is to be driven. This interruption however is casual or very slight and ineffective to appreciably slow down the ram, which is caused by t e impact of the plunger against the anvil or abutment and by the impact of the float 60 against the disc or diaphragm 33.

Saddle 54 is slidable transversely of the magazine and serves as means for stabilizing the tacker when placed adjacent a wall or in corners for easy access thereto and the rear grooved roller 50 is rotatably mounted on pin Bl fixed to the spaced sides 9 of the hollow case C which together with the U-shaped sheath S characterizes the frame or cover of the tacker, the marginal portions 62 of sides 9 (Figs. 11 and 13) being removably and closely received by the spaced sides 63 of the magazine until limited by the lower faces 64 of the sheath striking stop faces 65 of the spaced sides of the magazine. Thus the cover when closed is positioned relative to the magazine and the lower margins 62 of the case preclude upward displacement of the staples and depending lug 66 removably fits into position notch 61 to more properly position the front part of the cover in respect to the magazine for controlling the alinement of blade 30 with the staple driveway.

Projecting laterally of the sides 9 of the frame or pivoted cover is the actuator pin 68 movably guided in alined and arcuate slots 59. This pin carries the front roller 48 and is adapted to operate the pivoted yoke lb rotatably suspended from the fixed fulcrum pin H held by the spaced sides 9 of the case R. Spring 41 normally acts against roller 48 to hold or urge the pivoted yoke rearwardly causing the free portions or ends of the actuator pin 68 to be received and interlocked with the alined notches T2 in the wings or keeper means I3 of the magazines. By this arrangement the actuator pin 68 automatically interlocks with the magazine on completion of its closing stroke. To unlock the cover, the pin 68 is manually shifted forwardly thus causing yoke or supporting means 10 to pivot forwardly against the resistance of sprin ll and thereafter the cover may be swung away from the magazine.

To prevent buckling of the staple, the forward end of rail 42 (Fig. 14) is permanently secured on the inverted U shaped insert 83 having its front faces of the lower lateral flanges 8| serving as extensions for the front face of the rail while the side faces 82 are merely positioned against the inner sides of the magazine. In this way rearward tilting of the staple is completely prevented.

The upper portions of the laminations 39 also embody alined projections 85 disposed in positioning opening 86 in the front wall of the magazine to properly aline the laminations relative to the power spring and ram in the sheath which has its sides provided with spaced and alined ribs 81 for positioning the power spring and for reinforcing the sheath.

The case R is provided with the enlarged central opening 88 in which is positioned a rubber loop 89 in any suitable manner. This loop apart from being convenient to grasp is also readily accessible. It should be observed that in use the slidable plunger 35 of the driving means or ram never strikes the lower part of stop pin 36, there being adequate clearance between this stop and the plunger when latter is at its innermost position within the ram (Fig. 7).

By the present invention it is apparent that a novel method and practical structure have been provided in the matter of effectively driving staples into material of Various resistance.

While the invention has been described in detailand reference has been made to a specific application thereof, it is to be understood that the invention herein disclosed is not limited to such specific applications and it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In combination, a staple holding magazine having a raceway, a spring controlled follower in said magazine for shifting a staple into said raceway, reciprocable driving means including a blade projectible into and out of said raceway and comprising a slidably guided plunger, shock absorbing spring means, impact distributing means and resilient bumper means; power spring means acting on said driving means, means for slidably guiding said driving means and, blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward stroke of said driving means to interrupt said downward stroke, and means coacting with said distributing means towards the completion of said downward stroke to prevent solid compression of said shock absorbing spring means and to further interrupt said downward stroke and for stressing said bumper means.

2. In combination, a staple holding magazine having a raceway, a spring controlled slidable follower in said magazine for shifting a staple into said raceway, reciprocable driving means including a blade projectible into and out of said raceway and comprising a slidably guided plunger, helicoidal shock absorbing spring means, impact distributing means and resilient bumper means; helicoidal power spring means acting on said driving means, means for slidably guiding said driving means and blade, pivoted means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward troke of said driving means to interrupt said downward stroke, and means within said driving means and of a height less than said shock absorbing spring means for coacting with said distributing means towards the completion of said downward stroke to further interrupt said downward stroke and for stressing said bumper means.

3. In combination, a staple holding magazine having a raceway, a spring controlled slidable follower in said magazine for shifting a staple into said raceway, reciprocable driving means including a blade projectible into and out of said raceway and comprising a slidably guided plunger, helicoidal shock absorbing spring means, impact distributing means and resilient bumper means; helicoidal power spring means acting on said driving means, means for slidably guiding said drivin means and blade, manually controlled pivoted means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impart of said plunger on the downward stroke of said driving means to interrupt said downward stroke, and pin means within but of a height less than said shock absorbing spring means for coacting with said distributing means towards the completion of said downward stroke to further interrupt said downward stroke and for stressing said bumper means.

4. In combination, a stapl holding magazine having a raceway, a spring controlled follower in said magazine for shifting a staple into said raceway, reciprocable driving means including a blade projectible into and out of said raceway and comprising a slidably guided plunger, helicoidal shock absorbing spring means, impact distributing means and resilient bumper means; helicoidal power spring means acting on said driving means, means for slidably guiding said driving means and blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward stroke of said driving means to interrupt said downward stroke, and pin means within but of a length less than said shock absorbing spring means for coacting with said distributing means towards the completion of said downward stroke to further interrupt said downward stroke and for concomitantly precluding solid compression of said shock absorbing spring means and stressing said bumper means.

5. In combination, a staple holding magazine having a raceway, a spring controlled follower in said magazine for shifting a staple into said raceway, reciprocable driving means having a body and a blade secured to said body projectible into and out of said raceway and comprising a slidably guided plunger, helicoidal shock absorbing spring means for urging said plunger in a direction out of said body, impact distributing means, and resilient bumper means; helicoidal power spring means acting on said driving means, means for slidably guiding said driving means and blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward stroke of said driving means to interrupt said downward stroke whereupon said plunger is displaced in a direction inwardly of said body against the resistance of said shock absorbing spring means at which time the lower end of said blade is substantially flush with the bottom wall of said magazine, and pin means within said shock absorbing spring means and coacting with said distributing means towards the completion of said downward stroke to further interrupt said downward stroke and to compress said bumper means and to limit compression of said shock absorbing spring means.

6. In combination, a staple holding magazine having a raceway, a spring controlled follower i said magazine for shifting a staple into said raceway, reciprocable driving means having a body and a blade secured to said body projectible into and out of said raceway and comprising a slidably guided plunger, helicoidal partially compressed shock absorbing spring means for urging said plunger in a direction out of said body, impact distributing means and resilient bumper means; helicoidal power spring means acting on said driving means, means for slidably guiding said driving means and blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means said bumper means and to limit predetermined compression of said shock absorbing spring means, said driving means pursuant to said predetermined compression of said shock absorbing spring means continuing slightly downwardly to project said blade a slight distance beyond said bottom wall to complete said down stroke during compression of said bumper means.

'7. In combination, a staple holding magazine having a raceway, a spring controlled follower in said magazine for shifting a staple into said raceway, reciprocable drivin means having a body and a blade secured to said body projectible into and out of said raceway and comprising a slidably guided plunger, helicoidal partially compressed shock absorbing spring means for urging said plunger in a direction out of said body, impact distributing means and resilient bumper means; helicoidal power spring means acting on said driving means, means for slidably guiding said driving means and blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward stroke of said driving means to interrupt said downward stroke whereupon said plunger is displaced in a direction inwardly of said body against the resistance of said shock absorbing spring means at which time the lower end of said blade is substantially flush with the bottom wall of said magazine, and pin means within said shock absorbing spring means and coacting with said distributing means towards the completion of said downward stroke to further interrupt said downward stroke and to compress said bumper means to limit predetermined compression of said shock absorbing spring means, said driving means pursuant to said predetermined compression of said shock absorbing spring means continuing slightly downwardly to project said blade a distance beyond said bottom wall to complete said down stroke during compression of said bumper means, said shock absorbing spring and bumper means instantly pursuant to the completion of said down stroke operating to expand causing said driving means to automatically retract against the resistance of said power spring means.

8. In combination, a staple holding magazine having a raceway, a spring controlled follower in said magazine for shifting a staple into said raceway, reciprocable driving means having a body including a bore and a blade secured to said body projectible into and out of said raceway and comprising slidably guided plunger in said bore and in part projecting therefrom, helicoidal partially compressed shock absorbing spring means for urging said plunger in a direction out of said body, stop means to limit said projection of said plunger out of said body, a hollow rubber bumper of appreciable width and height disposed in said bore, a relatively thin impact distributing member, helicoidal power spring means acting on said driving means for urging the latter downwardly, means for slidably guiding said drivin means and blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward stroke of said driving means to interrupt said downward stroke whereupon said plunger is displaced in a direction inwardly of said body against the resistance of said shock absorbing spring means at which time the lower end of said blade is substantially flush with the bottom wall of said magazine, and

12 pin means within said shock absorbing spring means and coacting with said distributing member towards the completion of said downward stroke to further interrupt said downward stroke and to compress said bumper and to limit compression of said shock absorbing spring means.

9. In combination, a staple holding magazine having a raceway, a spring controlled follower in said magazine for shifting a staple into said raceway, reciprocable driving means having a body including a bore and a blade secured to said body projectible into and out of said raceway and comprising a plunger guided in said bore and in part projecting outwardly therefrom and including an opening substantially normal to said bore, a stop carried by said body and extending across said opening to limit projection of said plunger out of said bore, helicoidal shock absorbing spring means for urging said plunger in a direction out of said bore, a hollow resilient rubber bumper at one end of said bore, a relatively thin disc seated against said bumper by said shock absorbing spring means, helicoidal power spring means acting on said driving means, means for slidably guidin said driving means and blade, means for raising said driving means against the resistance of said power spring means, fixed abutment means to receive the impact of said plunger on the downward stroke of said driving means to interrupt said downward stroke whereupon said plunger is displaced in a direction'inwardly of said bore against the resistance of said shock absorbing spring means at which time the lower end of said blade is substantially flush with the bottom wall of said magazine, and pin means within said shock absorbing spring means but of a less height than the latter and coacting with said disc towards the completion of said downward stroke to further interrupt said downward stroke to compress said bumper and to limit compression of said shock absorbing spring means.

10. Staple driving means comprising a bore, a rubber bumper retained at one end of said bore, a disc Within said bore, a plunger slidably guided in said bore and in part projecting therefrom, a helicoidal shock absorbing spring interposed between said disc and plunger, means to prevent total compression of said spring, and means to limit projection of said plunger out of said bore.

11. Staple driving means comprising a bore, a ruber bumper retained at one end of said bore, a disc within said bore, a plunger slidably guided in said bore and in part projecting therefrom, a helicoidal shock absorbing spring interposed between and coacting with said disc and plunger, stop means within said spring to prevent total compression of said spring, and means to limit projection of said plunger out of said bore.

12. Staple driving means comprising a bore, a rubber bumper retained at one end of said bore, a disc within said bore, a plunger slidably guided in said bore and in part projecting therefrom, a helicoidal shock absorbing spring interposed between and acting against said disc and plunger, an interrupter within and of a length less than said spring to prevent total compression of said spring, and means to limit projection of said plunger out of said bore.

13. Staple driving means comprising a bore, a hollow rubber bumper retained at one end of said bore, a disc within said bore, a plunger slidably guided in said bore and in part projecting therefrom, means to limit projection of said plunger out of said bore, a helicoidal shock absorbing spring interposed between said disc and.

plunger for holding said disc against said bumper and said plunger against said limiting means and a pin within said spring to prevent total compression of said spring and adapted to abut said disc to compress said bumper on displacement of said plunger in a direction towards said driving means.

14. In a tacker, a magazine, a cover movably connected t said magazine for opening. and closing the latter, staple driving means carried by said cover, latching means, means swingably connecting said latching means to said cover, slidable staple follower means in said magazine, a spring looped over said latching means and having one leg connected to said follower means and having another leg extending along the length of said cover and including an end portion extending upwardly and anchored to said cover whereby upon reciprocating said cover relative to said magazine said follower is reciprocated, and said spring normally urging said latching means in a direction away from said driving means.

15. In a tacker, a magazine, a cover reciprocably connected to said magazine for opening and closing the latter, staple driving means carried by said cover, latching means, means reciprocably connecting said cover to said magazine, slidably guided staple follower means in said magazine, a spring looped over said latching means and having one leg connected to said follower means and having another leg extending along the length of said cover and including an end portion extending upwardly and anchored to said cover whereby upon reciprocating said cover relative to said magazine said follower is reciprocated, said spring normally urging said latching means in a direction away from said driving means, and means for automatically interlocking said magazine with said latching means upon closing of said cover.

16. Means to prevent buckling of a staple when driven downwardly in a raceway comprising in part an inverted U shaped rail, and an inverted U shaped insert secured in said rail. and having an end face flush with the forward face of the rail and including laterally extending flanges extending underneath spaced sides of said rail at the lower portions thereof and including lower front surfaces at the bottom of said raceway to support said staple against rearward tilting.

1'7. Means to prevent buckling of a staple when driven downwardly in a raceway comprising in part an inverted U shaped rail, and an inverted U shaped insert secured in said rail and having an end face flush with the forward face of the rail and flanges extending underneath spaced sides of said rail at the lower portions thereof and including lower front surfaces at the bottom of said raceway to support said staple against rearward tilting.

18. In combination, a ribbed cover carrying an abutment, staple driving means slidably guided in said cover and carrying a blade, a magazine closed by said cover and having means for guiding staples and including a staple raceway, slidable means carried by said driving means for impacting said abutment to interrupt the staple driving stroke of said blade, and cushion and supplementary cushion means to regulate the extension of said blade out of said magazine following said interruption and including means for causing a subsequent interruption of said driving means.

19. In combination, staple driving means comprising a bore, a bumper retained at one end of said bore, a disc within said bore, a plunger slidably guided in said bore and in part projecting therefrom, shock absorbing spring means inter posed between and acting against said disc and plunger, an interrupter within and of a length less than said spring means to prevent total compression of said spring means, and means to limit projection of said plunger out of said bore.

20. In combination, staple driving means comprising a bore, an annular bumper retained at one end of said bore, a plunger slidably guided in said bore and in part projecting therefrom, shock absorbing spring means interposed between said bumper and plunger, and an interruptor within and of a length less than said spring means to prevent total compression of said spring means.

21. In combination, staple driving means comprising a bore, a hollow rubber bumper retained at one end of said bore, a disc within said bore and against said bumper, a plunger slidably guided in said bore and in part projecting therefrom, a helicoidal shock absorbing spring interposed between and acting against said disc and plunger, and a pin within and of a height less than said spring and cooperating with said disc to prevent total compression of said spring,

22. In a stapling machine, a magazine for staples, driving means for successively ejecting a staple out of said magazine, closure means for said magazine and having a pivoted lever including a pivoted pawl at one end thereof for elevating said driving means, an anti friction roller carried at another end of said lever, and a pivoted handle for coacting with said anti friction roller to actuate said lever.

23. In a stapling machine, a magazine for staples, driving means, a cover connected to said magazine, driving means carried by said cover for successively ejecting a staple out of said magazine, aspring controlled normally raised pivoted lever having a spring controlled pivoted pawl for elevating said driving means, a normally raised handle pivoted to said cover for actuating said lever, a roller mounted at one end of said lever and adapted to be operated by said handle, means depending from said handle for straddling said roller.

24. In a stapling machine, a magazine for staples, a cover secured to said magazine, driving means slidably guided by said cover for successively ejecting a stapler out of said magazine, a pivoted lever having a pawl for elevatin said driving means, a handle pivoted to said cover for actuating said lever, anti friction means mounted on said lever and cooperating with said handle, and a guard carried by said handle and adapted to embrace a portion of said cover.

25. In a stapling machine, a magazine for staples, a cover pivotedly secured to said magazine, driving means slidably guided by said cover for successively ejecting a staple out of said magazine, a pivoted lever having a pawl for elevating said driving means, a handle pivoted to said cover for actuating said lever, anti friction means mounted on said lever and cooperating with said handle, and a guard carried by said handle and adapted to embrace a portion of said cover.

26. In a stapling machine, a magazine, a cover, means movably connecting said cover to said magazine for opening and closing said magazine, supporting means disposed within said magazine, means swingably sustaining said supporting means, pin means carried by said supporting means and projecting in part laterally beyond said cover, slidable staple follower means in said magazine, a helicoidal spring looped over said pin means and having one leg connected to said followe means and having another leg extending along the length of said cover, a member disposed within and at the rear of said cover, said last mentioned leg having an extension looped over said member and extending upwardly into said cover and having a terminal portion secured to said cover whereby upon reciprocation of said cover relative to said magazine said follower means is reciprocated, said spring normally urging said pin means in a direction away from said driving means, and keeper means for automatically interlocking with said pin means upon closin of said magazine by said cover.

27. In a stapling machine, a magazine, a cover, means movably connecting said cover to said magazine for opening and closing said magazine, supporting means disposed within said magazine, means swingably sustaining said supporting means, pin means carried by said supporting means and projecting in part laterally beyond said cover, slidably guided staple follower means in said magazine, a helicoidal spring looped over said pin means and having one leg connected to said follower means and having another leg extending along the length of said cover, a roller mounted within and substantially at the rear of said cover, said last mentioned leg having an extension looped over said rolle and extending upwardly into said cover and having a terminal portion secured to said cover whereby upon reciprocation of said cover relative to said magazine said follower means is reciprocated, said spring normally urging said pin means in a direction away from said driving means, and keeper means for automatically interlocking with said pin means upon closing of said magazine by said cover.

28. In a stapling machine, a magazine, a cover, means movably connecting said cover to said magazine for opening and closing said magazine, supporting means disposed within said magazine, means movabiy sustaining said supporting means, pin means carried by said supporting means and projecting in part laterally beyond said cover, slidably guided staple follower means in said magazine, a normally contracted helicoidal spring looped over said pin means and having one leg connected to said follower means and having another leg extending along the length of said cover, a roller sustained substantially at the rear of said cover, said last mentioned leg having an extension looped ove said member and extending upwardly into said cover and having a terminal portion secured to said cover whereby upon reciprocation of said cover relative to said magazine said follower means is reciprocated, said spring normally urging said pin means in a direction away from said driving means, and keeper means for automatically interlocking with said pin means upon closing of said magazine by said cover.

29. In a stapling machine, a magazine, a cover, means movably connecting said cover to said magazine for opening and closing said magazine, supporting means disposed Within said magazine, means movably sustaining said supporting means, pin means carried by said supporting means and projecting in part laterally beyond said cover, a roller on said pin means, slidably guided staple follower means in said magazine, a normally contracted helicoidal spring looped over said roller and having one leg connected to said follower means and having another leg extending along the length of said cover, a roller disposed within and towards the rear of said cover, said last mentioned leg having an extension looped over said last mentioned roller and extending upwardly into said cover and having a terminal portion secured to said cover whereby upon reciprocation of said cover relative to said magazine said follower means is reciprocated, said spring normally urging said last mentioned roller and consequently said pin means in a direction away from said driving means, and keeper means for automatically interlocking with said pin means upon closing of said magazine by said cover.

CALVIN P. KIPP.