US2321847A - Staple for stapling machines - Google Patents

Description

June 15, 1943. I OBSTFEQLD 2,321,847 7 STAPLE FOR STAPLING MACHINES Filed Jan. 2, 1941 n IIWHIIIIIHI j Him mum 1 INVENTOR 6 LOU OBSTFELD ATTORNEYS M lllllllll' ig- Patented June 15, 1943 D STAPLE FOR STAPLING MACHINE-S Lou Obsti'eld, Brooklyn, N. Y., assignor of one-'- half to Abraham Obstfeld, New York, N. Y.

Application January z, 1941, Serial No. 372,699

4 Claims.

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

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 tn 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 forloading, and it is therefore a very diflicult 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 difficulty and to prevent jams of this character.

The diiiiculty 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.

To the accomplishment of the foregoing and such other objects as will hereinafter appear,

as hereinafter are more particularly described in the specification and sought to be deflnedin the claims. The specification is accompanied by drawing, in which:

Fig. 1 is a partially sectioned side elevation of a stapling machine embodying features of my invention 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 such a 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 'l'| of Fig. 6; L

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

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

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

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

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

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. l, I there show a desk stapling machine of a known type, said machine comprising a base I2 carrying a clinching anvil l4. A stapling arm generally designated i6 is pivotally mounted on base 12. 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 a suitable 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 magazine may occasionally contain separated staple sticks with a loose staple 3|] therebetween. The diificulty arises principally during faulty or careless loading of the machine. The operator may drop the staple stick and so break it into a number of pieces, and then, rather than waste the staples,

attempt to force these pieces one after another into the machine. In prevalent practice, the machines are of the front-loading type with a safety pawl, such as is indicated at 30 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 during the loading of the staples into the machine. Or the jam may not be noticed during loading, but may manifest itself when the feed spring attempts to push the staples in the opposite direction, with the turned staple moving point first.

However, the difllculty is not caused solely by loading, but may arise during violent operation of the machine, as in factories using the machine for rapid production purposes. When the the resulting extension of the feed spring greatly reduces the feed spring pressure, and at this time the vibration or pounding on the machine may aiford suflicient separation to permit a staple to rotate. 1 7

On some occasions a loose staple may swing upwardly-over a large angle, as indicated in'Fig. 4. In such case, the ends of the loose staple 33 may move alongside of the staples 24 and so bethe limited 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

' feed pressure will tend than to jam it.

. use of bent heavy gauge sheet metal parts for I20. staples in the machine have been nearly used up,"

come wedged between the staples and the magazine walls. This produces a jam which will prevent further feed of staples, and may prove extremely difllcult to relieve.

The critical angle, theoretically, is 45. A staple at a less angle will be restored to normal position. A staple at a greater angle may be jammed.

An ordinary staple comprises legs disposed perpendicularly to a connecting top or bridge. In accordance with the present invention, this staple construction is modified by sloping a leg of the staple. This is indicated at 32 in Fig. 8. The

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 overrideone 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 to right the staple rather It will-thus be seen that by simply sloping the staple leg and by matingly sloping the staple magazine, jamming of'staples in the magazine may be eifectively prevented despite the use of liberal tolerances in the machine, and despite the the magazine.

The permitted angle of rotation of the staple leg is determined by the length of the leg relative to the clearance in the magazine, as well as the angle of the slope of the staple leg. The slope angle used for the leg may, of course, vary great- 1y.- A slight angle has some advantages, but decreases the permissible tolerance in the fit between the magazine passage and the staples. A large angle increases the tolerance and decreases the permissible swing of the staple, but may in-" troduce the disadvantage of reducing the strength of the staple leg against buckling when penetrating thick or hard material. I recommend an angle between five and thirty degrees, with an angle of ten to fifteen degrees as probably preferable for a satisfactory compromise between the advantages and disadvantages of more extreme angles.

- Referring now to Fig. 9, I there show a stapling machine having a conventional straight-sided other leg 34 may also be sloped outwardly, but I find it better to leave this leg perpendicular to the bridge 36. The staple magazine of my improved machine is made to fit the sloped leg staple, that is; the wall 38 of the staple core and outside wall 40 of the magazine are sloped to mate with the slope of staple leg 32.

' The inner wall of the magazine is thinner and mating with the same.

staple drive channel with a driving blade 52 The permanent clinching anvil 54 is generally conventional, eizcept that the clinching slot 56 is preferably made deeper and curved to more gradually turn the staple leg 32, than is the case with clinching slot 58 and the perpendicular leg 34. In other words, clinching slot- 58 may be conventional, but clinching slot 56 is modified to compensate for the fact that the leg 32 slopes outwardly.

may be fitted to the staples fairly accurately.

' The outer wall is of heavy gauge metal, making an accurate fit very difficult to obtain. The manufacturer usually aims for a passage fifty per' cated at 44. Now it will be seen in Fig. 6 that the position 44 represents the maximum swing of the staple, for the tip end of the staple leg has already reached and engaged the magazine wall 40. Moreover, in Fig. 7 it will be seen that this rotation 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 When it comes to temporary clinching, the outward slope of the leg 32 constitutes an advantage. Thus, referring to Figs. 10 and 11, I show an anvil having an inwardly directed clinching slot 60 and an outwardly directed clinching slot 62. It is evident that the initial outward slope of the staple leg 32 facilitates the outward clinching of the same in slot 62. In fact, the slot 62 may,

if desired, be made shallower than the slot 60.

This leads to a temporary fastening of the type illustrated in Fig. 11. Some manufacturers prefer a temporary fastening in which the staple legs are both turned outwardly. Such an anvil may, of course, be used in lieu of that .shown in Figs. 10 and 11, and in such case the perpendicula leg 34 will be turned outwardly in normal manner, while the sloping leg 32 will be turned outwardly even more readily.

Both permanent and temporary clinching slots may be provided on a single anvil, said anvil being movable in conventional manner to bring either type of slot beneath the staple driving blade. One arrangement is shown in Fig. 1, in

which the anvil u is slidable longitudinally or 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'perpe dicular 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 I4 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.

' cardboardfabrlc or the like 16, to a piece of wood 18. Now when a sloping leg staple isused, the

leg is preferably initially straightened t0 Pe 'Pi ndicular relation, as shown at 32' in Fig. 13, before driving the same into the wood 18. After the staple has been driven, the leg 32 tends to swin outwardly, because of its own resilience, and thi 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 fulfllled 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 cammedto 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 deto be defined in the following claims.

I claim:

1. A staple for use in a magazine type stapling.

machine of ordinary character except that the staple guide passage of the magazine slopes ,to

receive a matingly sloping staple leg, said staple being formed of a slender, uniform, readily deformable wire, and having 3:. bridge with two legs depending therefrom, one of said legs being perpendicular to the bridge. and the other sloping at an angle of from five to iihirty degrees from perpendicular.

2. A staple for use in a magazine type stapling machine of ordinary character except that the staple guide passage of the magazine slopes to receive a matingly sloping staple leg, said staple being formed of a uniform wire, and having a bridge with two legs depending therefrom, one of said legs being perpendicular to the bridge,

and the other sloping outwardly.

3. A staple for use in a magazine type stapling machine of ordinary character except that the staple guide passage of the magazine slopes to receive a matingly sloping staple leg, said staple being formed of a slender, uniform, readily deformable wire, and having a bridge with two legs depending therefrom, one of said legs being perpendicular to the bridge, and the other sloping outwardly at.an angle of from five to thirty degrees from perpendicular.

4. A staple for use in a magazine type stapling machine of ordinary character except that the staple guide passage of the magazine slopes to receive a matingly sloping staple leg, said staple being formed of a slender, uniform, readily deto the bridge. LOU oss'rr'mn.

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