US2374373A - Wire stitching machine - Google Patents

Description

April 1945- J. l. NAVSMITH ET AL 3 WIRE STITCHING MACHINE Filed July 17, 1941 4- Sheets-Sheet 1 v In men fa r-s Job/7 [rt [fly Was/1717f; X Mlfred/fzk'b By.-- M, m 9 4% April 1945 J. l. NASMITH ETAL 2,374,373

WIRE STITCHING MACHINE Filed July 17. 1941 j 4 SheetsSheet 2 m s a.

Attorneys April 24, 1945- J. I. NASMITH ET AL 2,374,373

WIRE STITCHING MACHINE Filed July 17, 1941 4 Shets-Sheet 3 W W/Z and. Wz/fred Kirby Join [rill/1y A as/mil;

. Filed July 17, 1941 4 Sheets-Sheet 4 m i W 0 2 w j fi 2 \\A \\\AM m 2 a g i 1 v w 4 v 4 Q t. /2 M v j and Wilfred Kirby Attorneys .the increased thickness;

' staples.

Patented Apr. 24, 1945 WIRE STITCHING MACHINE John Irving Nasmith, Chislehurst, and Wilfre'd- Kirby, London, Englan d, assignors to Vickers- Armstrongs Limited, London, England, a British company Application July 17, 1

941', Serial No. 402,362

In Great Britain May 25,1940 I M v I (cu-11) I '2 Claims.

This invention relates to wire stitching machines and more particularly to corner wire stitching machines adapted for fastening or stapling together work pieces or parts of work pieces at right angles to each other, said pieces or parts being supported during the fastening or stapling operation on a work support or anvil, the supporting surfaces of whichlatter are also at right angles to each other.

In machines at present in use, a pieceof wire to be used for making a stitch or staple is cut from a reel and is first bent to form three sides of a rectangle or in other words anelement of substantially inverted U-shapew For the sake of clarity, the two portions bentat right anglesto the remainder of the wire will be hereinafter referred to as the legs of. the staple, while the portion serving to connect such legs will be referred to as the crown. In allsuch known machines the legs of the staple so formed are folded inwardly towards each other so that on applicationof the staple to the surfaces ofv the work pieces tobe fastened, said legs will be directed approximately normal to such surfaces and during penetration of the latter the crown is subsequently bent over the corner of the work tothe required rectangular form. This method of corner stitching suffers from certain disadvantages since when staples of a given crowndimension are applied to workof different thicknesses the ends of the staples which project through the work and are subsequently bent over or clinched to secure the stitches, must necessarily become shorter and shorter as the thickness of the work increases, even although the necessary wire is provided in the staple for The only means of avoiding this decrease in the length of the clinched ends is toincrease the crowns of staples required for thicker work and that would involve changing of all parts concerned in forming the Alternatively, all staples could be constructed for the greatest thickness likely to be handled, in which case clumsy and wasteful stitches would occur in all works of lesser-thick nesses. Another disadvantage with the known method is that as the crown of the staple has continually to change its shape whilst the staple is being driven through the work, .it is difiicult and mechanically complicated satisfactorily to support said staple against collapse when penetration is resisted. Further disadvantages reside in the fact that the-mechanisms requiredto carry out this method of stitching, aremore complex, less robust and efiicient and considerably less re liable in operation'than those of other types of wire stitching machines. r g

It already has been proposed directly to form, drive and clinch staples, hereinafterreferred to as angle type staples, wherein thecrown, is bent initially to the right angle form; andeachleg extends. at an angle of to the adjacent portion of said crown. It-will be appreciated that with this type of staple the legs have to penetrate the surface of the work piecestobe stitched at an angle of 45 and that in order toclinchsthe stitch beneath the workthe projecting endsof the staple legs have-to be turnedthrough an angle of at least 13 5. ln suchicases however, the crown of the staple doesnotchange its formas the stitch is driven and also as thetheoretical point of egress of the legsot the staple from the work pieces is in an invariable relation to the inside corner of the work, the size ofthecrown can remain invariably up to the limitoisthickness, represented by the 1 joint ;of the two pieces to be joined, falling safely within the crown of the stitch. No machines for satisfactorily forming, driving and clinchingsuch, angle type staples have, however, yet been produced audit is the chief object of the,inyention to providea staple supporting. mechanism which will ensure proper support both for the legs, and the inverted -V shaped crown of the staple and which supporting mechanism. embodies as-an essential feature a support'havinga cross section which ,fits the-inverted V shaped top of a-recessin,a-driverwhich engages over the staple-to drive-it intothe work,- and which support also conforms to the; inverted V shaped corner of the work to be stapled.

It will be clear that in order to drive and clinch angle type staples, wherein each leg is driven into the work at an angle of 45 to the appropriate surface of the latter, certain conditions must be satisfied, which may be set. out as follows:

(a) The staple must necessarily be rigidly and securely mechanically supportedat all stagesof penetration and in all directions.

(12) The forces set upon penetration of the material by the stapleand strongly tending to push thejoint open during penetration must be counteracted, and v 1 (0) Means mustbe provided to turn with certainty the protruding ends of the staple legs on theinside of thew-ork through an angle of atleast 135 and to press thesamehome without distortion in or damage tothe .rnaterial being stitched.

The present invention is concerned with satisw tying the first mentioned condition,

In order that-the, said: inventionmayzbe clear- 1y understood and readily carried into effect, the same will now be described more fully with reference to the accompanying drawings, in which: Figures 1 and 2 illustrate the application of an inverted U-shaped staple of well known form to thin and thick material respectively, the figures showing the disadvantages of the particular type; Figures 3, 4 and 5 illustrate the type of staple employed with the machine constructed in accordancewith the present invention and showin the advantages of the use thereof;

Figure 6 illustrates the machine in the process of cutting off the required length of wire to form the staple;

Figure 7 is a sectional view drawn to an enlarged scale of the loop bar and illustrating the manner in which the staple is formed;

Figure 8 illustrates in side elevation to an-enlarged scale the upper and lower clincher guide plates;

Figure 9 is a vertical section on the line 9-9 in Figure 6; v

Figures 10 and 11 illustrate in side elevation and frontelevation respectively the staple support in operation; I

Figures 12, 13, 14 and 15 illustrate the staple in the process of being driven and clinched;

Figure 16 is a perspective view of one of the clinchers;

Figure 17 illustrates inclincher guides; and 1 7 Figures 18 and 18a illustrate in side-elevation and end elevation respectively the upper clinch-'- er guide plate. Figures 19 and 19a illustrate in side elevation and end elevation respectively the lower clincher guide plate. I

The disadvantages associated with the use of the usual type of staple will be apparent from a consideration of Figures-1 and 2 which show its application respectively to thin and thick material. It will be apparent from Figure 2 that even if the necessary wire is provided in the stitch to allow for the increased thickness,'the clinched ends must necessarily become shorter and shorter as the thickness increases due to the factthat the legs ofthe staple-are driven into the material at' right angles to its surface. This is not so with the type of staple shown in Figures 3-5 used in carrying the present invention into effect, wherein the legs of the staple are driven into the material at an angle of 45 to its surface, as by increasing the length of wire used in the construction of the staple, when dealing with material of increased thickness, the length of the clinched ends can be maintained constant for thin and thick material.

In the embodiment hereinafter described, the mechanism of the stitching machine is generally of known type and includes a reciprocatable former I which is adapted on each operation to bend a length of wire 2, cut from a reel, over a loop bar 3 (see Figures 6 and '7) in order toform an angle type staple 4, which latteris adapted subsequently to be driven into the work by a longitudinally reciprocatable member 5 hereinafter termed a driver. The arrangement is such that the loop bar 3 will be withdrawn from each side elevation the staple prior to the driving operation, the loop bar,

3, the driver 5, the former I being operated in timed relation all in well known manner. The driver, the lower end of which is formed to conform to the angled crown of the staple, may 'for example comprise a single piece rod like member which is slidable longitudinally in a groove or recessin the former, sa id'drlver' and former be-.

ing reciprocated through the medium of suitably profiled cams or the like, which latter are driven in any suitable manner. In accordance with the stated object of the present invention in order to attain the first requirement, designated (a) above, a member is provided which is hereinafter referred to as a staple support and which is shown in Figures 9, 10 and 11, said support 6 beingadapted, after the staple has been formed and the loop bar 3 has been withdrawn prior to driving, to support the staple internally at all stages of penetration of the work by said staple. The staple support 6 combines three features, namely, it is associated with and shares in the translational movement of the former it is provided with two fiat sides 1 which support the legs of the angle staple, and finally has an upper profile such that, at any stage of the process of driving the angle staple through the work, the section of the upper profile in the plane containing the centre line of the crown and legs of the staple will include two surfaces 8, inclined at to each other and corresponding to the invariable inner profile of the crown of the angle staple. The staple support may be slidably mounted in the former or in an element associated therewith or again in apreferred construction it may be mounted for pivotal movement about a pin or the like 9 (see Figure 9) mounted on or carried by the former I. As will be seen byFig. 11 the part of the support 6 which enters'the staple has an inverted V shaped ridge constituted by the converging surfaces 8 and an inverted V shaped channel along its lower edge-constituted by the upwardly converging. surfaces 8a which, as shown in'Fig. 13, engage flush against the rectangular corner of the work. 16 to cooperate with clinching means as hereinafter described, such clinching means forming the subject of an invention described in application Serial No. 538,410 filed June 2,1944. 1 The arrangement is such that the staple support 6 will be progressively retracted from the staple as the latter is driven into the work but preferably resilient means ,are associated with said support adapted normally to urge the same into its operative position wherein the staple will be supported. In those cases where the staple support is mounted for pivotal movement with respect to the former, a guide rod ID or the like maybe pivotally connected to the support-at-a point I I displaced with respect to the pivotal axis of the latter, said rod being freely supported for sliding movement at a point l2 adjacent its; opposite end in a bracket orthe like mounted on or carried by the former while a compression spring I3 is disposed around said rod being adapted to bear at one end against the staple support and at the other against the bracket or the like and serving to urge said support into its operativepo. sition. The outer surfaces of the legs of each angle staple are supported during penetration by virtue of the fact that they aremaintained, due tothe presence and action of the staple support, in grooves provided in the former in'the usual well known manner. The outer surface of the crown of each staple is' supported directly by the base of the driver which, as the angle of the angle staple remains invariable during the driving of the staple into the, work may, as above indicated,

be formed in a single'piece, the working end being formed witha 90 profile corresponding with the crown of the staple. It will be appreciated from the foregoing that the angle staples aremechanically rigidly-supported in all directions and at all stages of insertion into the work being: supported internally by the staple support ana -externally by the grooves in the former and by the .lower end of the driver. The staple forming and driving mechanism can operate substantially in the same way as for forming, driving, and supporting staples of the usual rectangular inverted'U-sh'ape as used for stitching flat as distinguished from angular work and consequently this mechanism can be made as robust, eflicient and reliable as in those forms of wire stitching machines." such mechanism, however, is well known and further reference is not necessary herein.

In order to satisfy the second requirement, designated (b) above, namely to prevent-the forces, set up by resistance of the material to penetration, from displacing'the work on the: work-support or anvil 14' (see Figures 6, 8, 12, 13 and which, in the case of driving angle staples, become very strong forces, said work support or anvil I4 is formed with serrationsor the like 15 (see Figure 8) in that portion thereof which is immediately opposite to the former. The high points of the serrated portion or portions are slightly elevated above the general surface of the support or anvil and are so profiled that as soon as the work I6 is clamped to the anvil by the base of the former, the serrations or the like will prevent sliding movement of the Work down the sloping faces of the anvil or work support.

To achieve the third requirement, designated (0) above, it is necessary to provide special means in that part of the stitching mechanism which is adapted to turn down the protruding ends of each driven staple ontothe inside of the work. This special means, is as beforesaid, the subject of application Serial No. 538,410 filed June 2, 1944,, but is described herein for a complete understanding of the invention. As above indicated, such projecting ends have to be turned through an angle of at least 135 and in order to avoid any distortion of the stitch and damage to the material it is essential to ensure, more especially at the earlier stages of the clinching operation (see Figures 13 and 14), that the turning over of the projecting ends [1 does not set up tearing forces in the material or in other words to ensure that a stitch can be substantially satisfactorily formed and clinched whether or not the material is present on the work support or anvil.

In accordance with the invention, a pair of clincher members l8 (shown in detail in Figure 16) are provide which are so mounted as to turn about virtual axes at each side of the stitch, said axes being so chosen as to be just outside the theoretical points of egress of the staple legs I1 and axially co-planar with the top faces of the anvil or work support 14. The clinching surfaces of the clinching members [8 which actually operate on the projecting ends of the wire are so formed that they appear in front elevation as radii from the virtual axial centres and they are of such length as eifectually to cover the clinched ends of the stitch at the completion of the clinching operation. If these radial operating surfaces are initially disposed at an angle of about 45 to the centre line bisecting the angle formed by the work supporting faces of the work support or anvil and supported in this position whilst the staple is being driven, the ends of the staple to be subsequently clinched will be positively curved inwardly as they protrude from the inner surface of the work without setting up any undesirable forces on said work (see Figure 14). An initial turning of the wire ends through approximately thus'takes place before any actual movement of the clinchersoccurs. When the stitch is completely driven, the arrangement is such thatthe driver will'remain' stationary and will hold the crown of the stitch while the clinchers are'operated and revolved about their virtual axes until contact is made withthe internal surface-of the work. During the clinching operation, it will be appreciated that until the clinchers reach the position wherein they contact with the inside'surfaces'of the work contact between said'clinchers and the protrudingstaple legs only takes'plac'e at the extremity of the-latter so that themax'imum leverage isused to turn over the legs throughout the whole process, and the direction in whichthe turning force is applied throughout is such that it diminishes as-much-as possible the force atthe points of the materialabout which the legsofthe staple are being turned;

Inone example, each'clincher member may comprise a sector shaped'element one face of which is formed with a sector shaped-recessor portion l9 cut away (see Figure 1-6), saidm'embers being rotatably supported'withi-nthe work support or anvil by means of upper and lower guide plates or the like, indicated respectively in Figures 17-19 by reference numerals 20 and 2|. The lower guide plate 2| which is disposed within the work support or anvil in a plane coincident, or substantially coincident, with the centre line of the driver is formed at its upper edge with a pair or part circular recesses 22, each of which is adapted to conform to the curvature of the periphery of a clincher member l8 and to support said member while allowing turning movement thereof about its virtual axis. The upper guide plate 20, which is disposed adjacent the lower is shaped to conform to the outline of the work support or anvil being of truncated triangular form and provided with a pair of projections 23 each of which is formed with a part circular surface 24 adapted to co-operate with the recessed or cut away portion of a clincher member in such a manner that the latter may .turn therearound while being supported in the appropriate recess 22 in the lower guide plate 2!. The projections on the upper guide plate contain the virtual axes referred to above about which the clincher members are adapted to turn. The upper and lower guide plates, which latter is also so constructed as to conform to the outline of the work support or anvil, are maintained in position on application of a cover plate which is applied to the end of said anvil or work support and conforms to the outline thereof. Those portions of the edges of the guide plates which are exposed when in position are preferably provided with serrations 25 (see Figure 8) or the like whilst the edges of the cover plate 26 are also formed with serrations 21 in order to assist in holding the work securely in position during the stitching operation as above described. Any suitable mechanism may be provided to revolve the clincher members between their two extreme positions, but since such latter mechanisms may follow the usual practice in this respect no special description thereof is calledfor herein.

I The operation of the machine is shown in Figures 6, 7, 9,12, 13, 14 and 15. In Figure 6 the wire is in process of being cut to the required length to form the staple, and in Figure '7 the staple is shown after being formed on the loop bar. Figure 9 shows the staple support in its inoperative position, the staple support being then moved into the position shown in Figure 12 to support the staple during the driving process.

.Figure 13 shows the legs of the staple protruding slightly below the under surface of the work, the staple support being partially withdrawn though still supporting the staple. In Figure 14 the legs are in process of being bent inwardlyby'means of the inclined faces of the clinchers and in Figure 15 the legs have been fully clinched under the action of the clinchers turning about their virtual axes.

What we claim and desire to secure by Letters Patent of the United States is:

1. In a corner wire stitching machine for forming and driving inverted V-crown-shaped staples of the type specified, the provision with the staple forming means of internal staple supporting means adapted to cooperate with the staple driver and the V-like corner of the work and the V- like crown and parallel legs of the staple to ensure that at any stage of the driving of the angle staples through the work, a section through the upper profile in the plane containing the centre line of the crown and the legs of the staple will include two inclined surfaces at right angles to veach other to support, completely the V-like crown of the staples.

2. In acorner wire stitching machine for driving staples with inverted V shaped crowns and parallel side legs into the adjacent converging wall parts of the corners of work pieces, the combination of a staple driver having an inverted V section driving end, an anvil shaped to support and present a corner of the work to said driving end of the driver, a staple forming means adapted to shape the staple to said configuration, an internal supporting member for the formed staple carried by the staple forming means and having two parallel fiat sides and an upper inverted -V shaped profile to engage the crown of the staple and channelled lower edge to engage over the corner of the work to be stapled, the support being engaged in the staple in such manner that the limbs of the crown and legs of the staple make parallel contact with the corresponding surfaces of the supporting member during complete penetration of the work by the legs.

J'OHN IRVING NASMITH. WILFRED KIRBY.

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