US2421429A - Stapling machine - Google Patents

Description

June 3, 1947. L. OBSTFELD I STAPLING MACHINE Original Filed Jan. 2, 1941 Fig-1&

INVENTOR LOU OBST F E LD BY f ATTORNEY Patented June 3, 1947 ZAZigiZt STAPLING MACHINE Lou Gbstfeld, Brooklyn, N. Y., assignor of onehalf to Abraham I. Obstfeld, New York, N. Y.

Original application January 2, 1941, Serial No.

372,699. Divided and this application November 3, 1942, Serial No. 464,365

7 Claims.

This invention relates to the art of stapling, and more particularly to an improved stapling machine and an improved staple for use with the same.

The primary object of my invention is to generally improve the art of stapling, and more especially stapling machines and thin wire staples such as are usually cemented together to form a stick.

A more specific object is to avoid jamming of staples in the staple magazine. Such a jam prevents further feed of staples by the staple feed spring, thus rendering the machine inoperative. In most machines the magazine is inaccessible except at one end for loading, and it is therefore a very difficult matter to free a, jammed magazine. After considerable study of this problem, I have come to the conclusion that these staple jams are caused by rotation of a free staple about its top or bridge until the legs point toward the legs of next adjacent staples, alongside of which they then become wedged. The troublesome staple may become free in the first instance due to loading of a staple stick against an unfinished staple stick, or due to breakage of a staple stick during loading or during violent rapid operation of the stapling machine. In most cases a loose staple is fed along with the others without difficulty, but in rare instances such a staple may swing upwardly about its bridge to a nearly horizontal position, and thus lead to a staple jam. One primary object of the present invention is to overcome this diflicultyand to prevent jams of this character.

The: difficulty might be overcome by using a very small tolerance or close fit of the staple magazine about the staples, but this would greatly increase the manufacturing expense. Moreover, the trend in design is to make these stapling machines out of heavy gauge sheet metal, but then it is practically impossible to provide a magazine passage having very small tolerance, as there is always a certain amount of spring or opening up of the material after it leaves the forming dies. There are also irregularities in the thickness of the metal.

Accordingly, an important object of the present invention is to eliminate staple jams, without, however, in any way reducing the tolerance or clearance between the staples and the staple magazine, and While making the magazine out of bent heavy gauge sheet metal parts.

This application is a division of my application Serial No. 372,699, filed January 2, 1941, now Patent No. 2,321,847, patented June 15, 1943.

such other objects as will hereinafter appear, my invention consists in the staple and machine elements and their relation one to the other,-as hereinafter are more particularly described in the specification and sought to be defined in the claims. The specification is accompanied by drawings, in which:

Fig. l is a partially sectioned side elevation of a stapling machine embodying features of my in vention;

Fig. 2 is a partially sectioned side elevation of a fragment of the magazine, and is explanatory of the invention;

Fig. 3 is a similar view showing a loose staple being returned to proper position;

Fig. 4 is a similar view of a .prior art machine showing a loose staple turned to nearly horizontal position;

Fig. 5 is a similar view showing how sucha staple may lead to a staple jam;

Fig. 6 is an enlarged fragmentary transverse section explanatory of my invention;

Fig. 7 is a fragmentary section taken in the plane of the line 1-1 of Fig. 6;

Fig. 8 is a transverse section through a staple magazine loaded with my improved staples; v

Fig. 9 is a transverse section through a stapling machine and clinching anvil at the staple driving blade; r

Fig. 10 is a similar section, but with the anvil moved for temporary fastening;

Fig. 11 is a view similar to Fig. 10, but showing the temporary fastened staple;

Fig. 12 is a section through a machine having a modified drive channel; 7

Fig. 13 is a similar view illustrating the operation of the modified drive channel; and

Fig. 14 is a section explanatory of an advantage of the modified machine and of my improved staple when used as a tacker.

Referring to the drawing, and more particularly to Fig. 1, I there show a desk stapling machine of a known type, said machine comprising a base I2 carrying a clinching anvil M. A stapling arm generally designated I6 is pivotally mounted on base l2. It comprises a, staple magazine l8 through which staples are fed forwardly by means of a feed spring (not shown) toward a staple driving blade 20, the latter being operated by asuitable plunger 22.

Referring now to Fig. 4 of the drawing, staples 24 are carried on a staple core 26 and are confined thereon by a. surrounding staple magazine wall 28. For any of a number of reasons, the

the staples, attempt to force these pieces one after In prevalent practice another into-the machine. the machines are of the front-loading type w1th a safety pawl, such as is indicated at 80 in Fig. 1',

and the staples are forced into the front end of the machine against the action of the staple pusher and staple feed spring. Thus the legs may become turned and overlapped in condition for a jam, or may even be jammed duringthe loadfest itself when the feed spring attempts to push the staples in the opposite direction, with the turned staple moving point first.

' Howeven the. difficulty. is-not caused solelyrby loading. but may: arise duringviolent operation ofthemachin'e; asin-f'actories using themachine for rapid production purposes. When the staples insthe machine have: been-nearly. usedup; .the resulting extension of-.-the. feed springi greatly-re.- duces the feedaspring pressure, and. at" this. time the vibration or pounding on the. machine-may afford sufficient separation toipermit a staple. to

rotate;: V J

On some occasions a loose staple may swing upwardly over a large angle; .as-indicated inv Fig. 4: In such case;,the:ends;of the loosestaple 30 may move alongside of the staples andsob'ecome wedged betweenathestaples and the magazine walls. This-produces ajam whichw-ill-prevent: further feed of'staples,;and mayproveextremelydifiicult to relieve. I

The critical angle, theoretically, is 45. A'sta pleat-a less angle will be-restored to normal position. A staple at a greater anglemaybejammed.

An ordinary. staple'compriseslegs, disposedperpendicularly to a connecting top-:orqbridge; In accordance 'withthe .present invention, this staple construction is modified by-sloping.2a.leg. of the staple. This. is indicated; at 32 in Fig. 8. The other leg 34 may. also: besloped outwardly. but, .I find it better to: leave: thisleg. perpendicular to the, bridge 36; Thestaple magazine. of my; in-iv proved machine is made to fit the sloped le jsta ple, that is, the wall 38- ofthe staple core and outside wall 40 of the magazineare-sloped to matewiththe slope of stapleleg 32. 1

The inner Wall of the magazine is thinner; and

may. befittedto the staplese fairly accurately.

The outer wall is of heavy; gauge metal ..making an accurate fit very difficult to obtain. The manufacturer usually aims for a passagefifty per cent larger than the staple thickness, but it often varies to double thev thickness. Even. with less than double thickness, astaple-jam mayjoccur inprior magazines because of the rounded section ofthe. staple wire, and. irregularities at the;stap1e ends. H

As a result ofmyangular stapleand magazine construction, the amount which the staple may wine t e id e 36 is severely limited. Thus, referring. to Figs..6 and 7, the -perpendicular or normal position of the; staple is indicated at 1 While anupwardly swung staple is. indicated at 44. 'Now it will be seen'inFig fiithatthe position- 44 represents themaximum swing .of .the stapl e, for the tip end of the; staple leg ghas already reached and. engaged the, magazine wall. 46. Moreover-,in Fig. Titwillbeseenthat this rota- .15. mg of the staples into the machine. Or the am may not be noticed during loading, but may mani-a 4 tion of the staple is well below 45, and despite the use of a very liberal tolerance in the staple magazine. When the staple swings only the limited amount shown in Fig. 7 it is still under control, that is, it will tend to be moved back to vertical position under pressure of the feed spring, as is illustrated} by the'successive positions in Figs. 2 and-3 of the drawing, instead of tending to jam, as is illustrated in Figs. 4 and 5. Even if the staple legs were to slightly override one another, the continued action of the machine will correct' the condition, because the staple legs ..will be disposed'collaterally for most of their length and-the-feed pressure will tend to right the staplerather than to jam it. Itwilllthus be seen that by simply sloping the snappin and by. matingly sloping the staple magazine, jamming of staples in the magazine may be efiectively prevented despite the use of liberal tolerances in the machine, and despite the use of bent heavy gauge sheet; metal parts for. the magazine...: i' i, a '11 The. permittedv angle s of: rotation. of thec'staple leg is determined by the length of the leg relative-to the=clearance in thermagazinepasiwelli as theangleof the slope of thestaple'leg'. 'Theslope angle used for the -leg.emay,.of coursegvary 'greate ly. A slight anglehas some advantages, .but:decreases the permissible tolerance in.th'e'.fit-between the magazinepassagejandthe staples; A large angle increasesth -tolerance. and .decreases the'pern'rissible swingiof the;staple, but;may introduce: the disadvantage: of. reducing the strength. of the staple; leg against bucklingowhen penetrating thick. or hard material lerecommend'an: angle between five? and thirty "degrees, with anangle'often'; to fifteen degrees asiprobably prefeablefor 1a satisfactory;compromise vbe. tween the advantages and disadvantages of more extreme angles. 3 Referringnow to Fig. 9,,I thereshow av stapling machineqhavinga conventional straightsided; Staple, drive channel 5,01With a drivingblade 52 mating with-the sarne... .Thepermanent clinch: ing anvil. 5.4 is generally. Conventional, except that the clinching-slot. 5fi=is-preferablygmade deeper and curved-t0 more gradually turn. ;the,.staple; leg 32, .thanisthe case with clinchingj-slot-58 and the perpendicular 1eg;34., In; other words, clinching slot 58" may beconventional, but clinchingslot 55 is modified to; compensate for thefact thatthe l eBlsIQms wa dly. I .,When it comesto temporary clinching. the outward slope of the leg 32 constitutes an ad-v vantagew Thus, referringto-Figs; 10cand 11,; I show an anvil having an inwardly directed, clinching. slot ill] and, an. outwardly directed clinching slot;.62., Itis evident ,that the.,initial; outward slope oi the. Staple leg .32 ,facilitates the outward clinching ofthesame in slot 62., In fact, theslot 62 may, if desired, be made shallower than the slot 60,, Thisleadsto atemporary fasteningof the type. illustrated in Fig. 11. Some: manufacturers prefer, a temporary fastening in which the staple legs areboth turned outwardly. Suchan anvil may, of course, be used in lieu ofthat shown in Figs. 10 and ll,-and,in;such;case the'perpendicular. leg-.34 will be.- turned. outwardlyiin normal manner, whil th sloping leg, 32. will be turned outwardly even more; readily. 1 Both permanent .anditemporary. clinching slots may be provided onaasingle-anvll; said anvil being'movableinrcon'ventional manner to bring either: type. of slot. beneathii the staple driving blade. One:'arrangement is-shown in Fig. 1, in

which the anvil I4 is slidable longitudinally of the base in order to bring either of its sets of clinching slots beneath the staple driving blade.

In Figs. 12 and 13 I illustrate a stapling machine having a modified staple drive channel. In this channel the wall 64 adjacent the perpendicular staple leg 34 is a straight wall, while the wall 66 adjacent the sloping leg 32 is turned inwardly at 68, thus narrowing the drive channel at to an amount commensurate with the length of the top or bridge 36 of the staple. The staple driving blade 12 is dimensioned to fit between the walls 64 and 10, that is, it is no wider than the bridge 36 of the staple. The action of this machine will be clear from inspection of the drawing. The staple remains in normal condition until the leg 32 reaches the inwardly sloped wall 68, whereupon the leg 32 is bent or cammed inwardly until it assumes the perpendicular relation shown in broken lines 32'. The action of the clinching anvil M will then be normal.

This arrangement is of advantage not only when the staples are to be clinched, but also, or perhaps even more importantly, when the staples are to be used for tacking purposes. In common commercial parlance, a stapling machine which clinches the staples is called a fastener, while a machine which merely drives the staple legs into a solid substance such as wood, is termed a tacker. Some machines are made with a base which can be turned out of the way, so that the same machine may be used as either a fastener or a tacker. The machine shown in. Fig. 1 is of this character, and when the base is swung out of the way, the staple may be driven without any clinching action in order to secure a piece of paper, cardboard, fabric or the like it, to a piece of wood 18. Now when a sloping leg staple is used, the leg is preferably initially straightened to perpendicular relation, as shown at 3'2 in Fig. 13, before driving the same into the wood 18. After the staple has been driven, the leg 32 tends to swing outwardly, because of its own resilience, and this helps bind the staple against accidental removal.

While I have illustrated permanent clinching slots in Figs. 12 and 13, it will be understood that the special driving channel there shown may also be used with temporary clinching slots, although the special drive channel is obviously of greater advantage for permanent clinching and for tacking, rather than for temporary clinching. However, in all of these cases there is some advantage in bringing the legs to parallel condition at the instant of driving the same, when the material to be stapled is of great thickness or unusual hardness or difficult to penetrate.

Both staple legs may be sloped, but inasmuch as the object of preventing jamming of the staple will be fulfilled while sloping a single leg, it is preferred to slope only one leg. The sloping staple leg may be sloped inwardly instead of outwardly to fulfill the desired object of preventing rotation of the staple about the bridge. Of course, if the sloping leg is to be cammed to perpendicular position at the instant of driving the same, the outwardly sloping leg is preferable to the inwardly sloping leg, because the means for camming the leg to perpendicular position is very simple, as was described in connection with Figs. 12 and 13. With an inwardly sloping leg the camming means would have to be automatically retracted as the staple driver descends.

It is believed that the construction and operation of my improved staple and stapling machine for use with the same, as well as the important advantages thereof, will be apparent from the foregoing detailed description thereof. It will also be apparent that while I have shown and described my invention in several preferred forms, other changes and modifications may be made in the structures disclosed, without departing from the spirit of the invention as sought to be defined in the following claims.

I claim:

1. A stapling machine comprising a staple magazine having a staple core and outer walls with a staple guide passage therebetween for use with staples having a bridge and an outwardly sloping leg, said passage having an outwardly sloping portion for receiving an outwardly sloping staple leg, the outer wall at said outwardly sloping portion being spaced from said core a distance to limit the extent to which said staple may rotate about its bridge as an axis.

2. A stapling machine comprising a staple magazine having a staple core and outer walls with a staple guide passage therebetween for use with staples having a bridge and one perpendicular leg and one outwardly sloping leg, said passage having a horizontal portion for receiving the bridge of the staple, a vertical portion at one side for receiving one leg of the staple, and an outwardly sloping portion at the other side for receiving the other leg of the staple, the outer wall at said outwardly sloping portion being spaced from said core a distance to limit the extent to which said staple may rotate about its bridge as an axis.

3. A stapling machine comprising a staple magazine having a staple core and outer walls with a staple guide passage therebetween for use with staples having a bridge and one perpendicular leg and one outwardly sloping leg, said passage having ahdrizontal portion for receiving the bridge of the staple, a vertical portion at one side for receiving one leg of the staple, and an outwardly sloping portion at the other side for receiving the other leg of the staple, said outwardly sloping portion being at an angle of from 5 to 30 to the vertical, the outer wall at said outwardly sloping portion being spaced from said core a distance to limit the extent to which said staple may rotate about its bridge as an axis.

4. A stapling machine comprising a staple magazine having inner and outer walls with a staple guide passage therebetween for use with staples having a bridge and one perpendicular leg and one outwardly sloping leg, said passage having a horizontal portion for receiving the bridge of the staple, a vertical portion at one side for receiving one leg of the staple, and an outwardly sloping portion at the other side for re-' ceiving the other leg of the staple, the inner and outer walls of said magazine being formed out of sheet metal, the outer wall at said outwardly sloping portion being spaced from the inner wall thereat a distance to limit the extent to which said staple may rotate about its bridge as an axis,

5. A stapling machine for use with staples having a bridge and an outwardly sloping leg, said machine comprising a staple magazine having inner and outer walls with a staple guide passage therebetween, said passage having an outwardly sloping portion for receiving the outwardly sloping leg Of the staple, the outer wall at said outwardly sloping portion being spaced from the inher Wall thereat a distance to limit the extent to which said staple may rotate about its bridge as an 1' axis; a staple drive, -.channel dimensioned to the width ofithe staple withits slopinggleg and a staple driverv operable insaiddrive;channel.-- vi, i 6 A stapling machine for. use with-staple having; an outwardly sloping leg, said-machine com pi'ising a staplezmagazine having inner; and outer walls \with a staple guide passage,;therebetween; said passage having an outwardly sloping vportion for receiving the outwardlyslopingwleg ,oi;-=;the staple, the said outer and inner walls atisaid ou w slo sper n be n eawee -d a to limit/the. extent .to, which said staple may rotate about itssbridge as an axis, and. a.$1 ple, drive channel; the upper -portion Qf"; which is a dimensinned to the widthpi the sloping legstaple put theJoweror discharge endof whichiis dimen; ed, o v h dth of th b id e of the, tapl thaupper wider .andlower narrower parts offthe channel being connected by a sloping guide or carnming surface adapted to bend a: sloping leg to perpendicula -r position.as the staple is being driven, the staple driving bladeibeingdimensioned to be; received inv thelower narrowenportiomof the staple drive;channel.i a 5i;

A st apling; machine for usewithstaples hav T ing abridge andone perpendioular leg and one outwardly-sloping leg, said machine comprising a staple magazine having inner and outeriwalls withza staple guide passage therebetween; said passage having a ehorizontal-zpolttion ior receiving th brid ed the staple a vertical portion; at one side .for receiving one leg-of the-.staple-,.,,and1.an outwardly tslopingnportion at theaotheriside for receiving the outwardly slopingleg of-ihesstaple, the said. outer and inner. wallsat said outwardly sloping portion being spaced a idistance to limit the extenttowhich saidstaple-may rotate about its bridgeaas-anaxis anda staple drive channel the'upper: portionof which; is dimensioned to the, Width of the sloping leg zstaple but the lower "or discharge end of which is dimensionedtoythe widthof the bridgeof the stap-le the-upper wider and lower narrower;v parts i of the channel being connected by a sloping guideorcamming surface adapted to; bend thesloping leg to perpendicular positionvas -the. staple isbeing driven, thestaiple driving 7 blade ibeing dimensioned to..- be. received in the, lower narrower portionof theistapledrive channfell A: =1 1 s. e ,LOUOBSTFELD nEEER ENoES CITED 1 The-following referencesarerof 'record in the file ofthispatentr v v UNITED STATES'PATENTS H V Number, i Date i 2,103,176 Randa1l- 1 -Dec; .21; 1937

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