US2155833A - Leather stretching apparatus - Google Patents

Description

April 25, 1939.

C. H. JOHANSON LEATHER STRETCHING APPARATUS 2 Sheets-Sheet 2 Filed Nov. 20, 1957 fiverzzor; 62271510715071;

Patented Apr. 25, 1939 UNITED-STATES PATENT omce LEATHER STRETCHING APPARATUS Carl Hugo J chanson, Los Angeles, Calif., assignor to Olivia S. Johan son, Los Angeles, Calif.

Application November 20, 1937, Serial No. 175,668 14 Claims. ((1149-21) This invention is a sheet gripping and stretch- In another aspect, an object of the invention ing apparatus in the general nature of the class is to'provide an elongate support having convexof inventions as set forth in my application Ser. section body presenting a more or less Wedge- No. 96,415, filed August 17, 1936, and as set forth shaped face and to provide elongate, parallel, re- 15 in my application Ser. No. 115,706, filed Decemaction parts whereby to press or flex an interher 14, 1936. posed sheet of leather, or other adaptable mate- In the machine disclosed in the application No. rial, into conforming engagement with the said 115,706, there is provided a pair of opposed carface; the said reaction parts preferably being riages or slides each having a gripping segment of resilient, deformable character so as to more or leaf slidably mounted thereon so as to bring or less adapt to the configuration of the relative 10 certain gripping parts into effective engagement and cooperative wedge-like support. In this conwith portions of a sheet of leather, as a glove nection, an object is to provide reaction parts skin, draped over certain portions of the slides in the nature of parallel rows of relatively indewhereby to effect the uniform stretching of the pendent, resilient, and, if desired, deformable,

5 skin as the slides are forcibly separated. isolated abutment-forming pads over which par- The present invention has for an object to proallel rows the incidentally presented portion of the vide a simple but highly eflicient improvement in sheet being stretched will automatically bridge the gripping means of the machine. while motionless or slipping thereon during Also an object is to provide an improvement process.

in the form of the leather gripping assembly In the preferred form of the leather bridging 20 shown in my application Ser. No. 151,707, filed back-rest this is made of fairly soft rubber so July 2, 1937, particularly in the back-cushion feaas to quite readily conform to the cooperative ture thereof. gripping or pressure applying wedge member It is a purpose of the instant invention to prowhich presents a firm effective leather engaging 26 vide a back-cushion having the function of setsurface and is preferably of rubber for its fricting up a desired degree of tension in the gripped tional efficiency to place a desired drag on the leather which gradually diminishes in each direcleather to effect its elongation under tension tion from a central or medial line of tension in while the leather may be permitted, under suitdirections lateral thereto for reasons and purable control, to relatively slip through the .80 poses well known to the skilled artisan; that iS closed gripping means. It is understood that the 30 to say, to effect the even distribution of latent term rubber includes its functional equivalent. stretch in the skin being treated so that true- If b th of th co-acting members of t gripsize glove blanks may be reliably cut from variping means are f bb an excess of drag may OHS portions of the finally Stretched Skinresult and therefore an object is to provide a less Additionally, it is a Purpose to provide for the frictional medium to one side of the interposed 35 '40 Particularly, an object is to provide a leather which may be tensioned in bridge-like manner ready change of the degree of reaction of the back-cushion by provision of easily interchanged cushion strips each provided with a graduated resistance capacity different from the other.

skin on which the skin may slide with much reduced drag while under gripping pressure at the bridge zone and still provide for fiexureof the skin over the pressure member.

The invention consists of certain advancements 40 in this art as set forth in the ensuing disclosure and having, with the above, additional objects and advantages as hereinafter developed, and whose construction, combination and details of an elongate contiguous zone of a skin as this means and the manner of P? and the is interposed for gripping action with or without method treatment. the i W111 be w relative slippage on the back-rest while the manifest m the decnpplon of annexe? bridged portion of the leather is subjected to tratwe apparatus; bemg'underswod that modl' drawing or stretching device in which there is provided complementary gripping members one of which is provided with spaced, parallelline platen o-r back-rest cushioning means across pressure of a Presser member having an elongate fications, variations and adaptations may be re- 50 pressing wedge operative by relative forward mo- Sorted Within the PD p p and l tion to tensionally flex the bridged portion of the of the mventwn as it 18 more dlrec ly claimed leather, then incident to the parallel, spaced e a tery platen parts, inwardly between said parts 'to Figure 1 is aplan of a machine incorporating 65 effect the desired stretch of the leather. the invention.

Figure 2 is a detail cross-section of the gripping means of one slide of the machine.

Figure 3 is a top edge plan of a preferred form of the bridging or back-rest device, and

Figure 4 is a frontal elevation thereof; the device being shown as longitudinally broken in each figure.

Figure 5 is a perspective of a fragment of a modified form of the bridging, cushion device, and Figure 6 shows another variant.

Figure '7 is a plan showing a compound-curve line of skin grip.

It is well known to the leather glove manufacturer that certain portions of each full glove skin is thicker and stiffer than other portions and it has long been the laborious practice to draw out or stretch each skin by hand along palm-width zones successively across the skin, both lengthwise and cross-wise thereof with the intention of equalizing its final stretch in the ultimate glove blank.

In the aforesaid applications are shown means for gripping the skin along continuous spaced lines and for relatively separating the lines of grip with or without slip of the interposed skin for stretching it in one operation for the full length of the skin between the gripping lines.

It is very desirable to provide for differential pressure and tension of the gripped and tensioned zone of the skin along each gripping line in such manner that the pressure and tension decreases in each direction from the longitudinal center of the gripped zone, as for instance, each way from the stiff, longitudinal back center of a skin toward the flanks. Thus the stiff back is subjected to the highest degree of grip and tension to bring it to equal flexure and stretch value with the flanks.

A particular form of stretch device is shown herein. 1

A table 2 is provided with a pair of opposed, coplanar slides 3 and 4, of U-shape plan, which are movable toward each other concurrently or from each other concurrently on supporting ways 5 by any suitable means, which may have a motivating wheel W. An accordion guard G connects the slides or carriages 3-4 and covers subjacent mechanism operating the slides and protects an applied skin S when draped from slide to slide so that its opposite edges may be tucked between later described gripping means while the slides have been moved inward to contiguous relation for subsequent relative separation to stretch the applied and gripped skin. For a disclosure of various forms of slide actuating means reference is made to the above mentioned patents.

Mounted in any suitable manner on each slide 3-4 is a transverse, rigid, fiexing or breaker blade 6, Fig. 2, presenting a horizontal, upstanding top edge portion above the relative slide top; the blade here being shown as arranged along the outer, vertical and, in the disclosed form, concavely arcuate end face of the slide so as to support the draped skin S.

The gripping means includes a stationary back rest device on the slide and a relatively movable presser assembly here shown as slidably mounted on its slide 3-4 though it may be mounted directly on the table as shown in application No. 151,707.

The back-rest device here shown embodies a pair of continuous or substantially continuous, lines of yieldable buttresses or supports so relatively spaced that a bridge zone Bis produced for the full length of the elongate line of buttress ,ping effort on the gripping surfaces.

support, that is, from one edge to the opposite edge of the interposed skin. The buttresses are shown as consisting of upper and lower, spaced lines of yieldable pads or cushions Ill-II attached to a basal strip l2; the pads Iflll and the strip [2 preferably being moldedin one piece of rubber of fairly deformable nature.

The cushion strip [2 is removably mounted as a unit against the exterior face of the relative breaker strip or blade 6 of its slide.

Opposing the cushioning back rest |llll of each slide is a relatively movable presser assembly including a very rigid, transverse leaf 20 whose ends are slidably mounted at 22 in relative ways 23 in the slide 34 so as to be readily moved toward or from its coordinate, leather supporting back-rest llJ--l I.

The inner edge or face of the leaf 20 is complementary in plan to the contour of the opposed back-rest IllH, that is, it is as here shown, convexly arcuate and has an applied, elongate, bodily removable, presser member 24 provided with a projecting, convex-section or wedge-like ridge 25 along its face exposed to the opposite back-rest.

This presser device 24--25 is preferably of a fairly stifi or firm rubber and is secured by metal ribbons 26 and screws 21 to the leaf face in such a position that its ridge 25 will move into register between the upper and lower lines of cushion parts Iil-ll and will therefore flex or bow the incidentally present bridge zone B of skin introduced therebetween and extending from one slide to the other.

For the purpose of avoiding excess of drag due to large area of rubber contact with the bridged skin between and on the pads Ill-4 I and the presser ridge 25, a pliant mantle 21 of cloth or other material having a smooth or sleek face 28 is fixed between the pad bed and the presser ridge 25 in such manner that the interposed skin S may slip quite free of friction on the sleek face. The mantle 27 is releasably secured to its slide along its top edge as by simple snap-fasteners 29 to cover the back-rest pads and present the sleek face toward the cooperative, rubber ridge 25. Thus the intervening skin S slides easily on the sleek face 28 of the mantle when subjected to holding or slipping pressure, as desired, by the wedge 25 of the controlling leaf 20.

The movable leaves 2!] are provided with suitable handles 30 or other control means, whereby they may be moved in or out to grip or release the bridged leather or skin. Suitable brake means, as shoes 3| are fixed to the relative slide 34 to hold an inwardly adjusted leaf 20 with desired pressure on the presented skin supported on the adjacent mantle 21.

It will be noticed that the inner edge faces of the two leaves 20 of the slides are convexed inwardly toward each other. This results in a higher degree of stress of the narrowest portion of the leather crossing from one to the other and gripped by the elongate gripping means.

. A feature of the invention is to provide a differential pressure or gripping effect along the zone B of skin positioned along the line of grip- This is accomplished by a gradually decreased degree of the cushion reaction of the lines of gripping media, as the pads, each way from the longiare of gradually decreasing length (from their basal part) in sequence from the center of their line. Therefore, as the presser member ridge 25 is moved against the bridge B of leather the highest (or longest from their base) are first compressed and then the others to each side, along the line, are compressed each with less gripping reaction than the next, nearer the center of the line. Thus when the presser leaf 20 has been pushed in to the desired degree the longest pads are most compressed and react with highest holding efiort on the leather.

It will now be seen that if the skin at zone B is allowed to relatively slip between the presser wedge 25 and the back cushion (l0ll) that portion traversing upwardly on the mantle 2'! at the most compressed portion of the back cushion will be more firmly retarded'in comparison to that at the lesser compressed back cushion to each side of the maximum reaction point, or center of the line, andthe thicker or stifier portion of the skin will be under greater tension from slide to slide.

A form of back-rest or cushion is shown in Fig. 5 in which the bed strip l2 has substantially continuous, spaced ribs I0* l l of gradually decreasing height endwise from the longitudinal center of the strip, the crests of either or both of which may be transversely serrated to form isolated pad faces, if so desired.

In the form of the cushion device of Fig. 6 the pads lfl may be of any depth and are shown of gradually decreasing diameter from the lengthcenter of the strip l2 so that the gripping pressure diminishes toward the ends of the closed co-operative elements of the gripping device.

It is found in stretching a skin across its length from head to tail that least tension is required in the cross zone from flank to flank and that the tension should be increased toward and at the neck, and toward the rump but that the tension from the rump to the tail edge of the skin should be decreased. This is accomplished by a means shown in Fig. 7 as including two pairs of opposite, relatively separable gripping assemblies or devices each including an inner pusher slide or member 3 3 and an outer presser leaf or element Zo -440 which latter elements instead of being slidably mounted on relative slides 3 3 are slidably mounted on suitable frame rails or guides 30. The slide members 3 and its coordinate presser element 29 have their facing edges which cooperate to grip a skin sinuously curved on a line L from end to end; the line of the gripping assembly 3* ----2l) being symmetrically reversed as to the gripping line L of the opposite assembly 3 -20 The head end of the skin is draped on the upper converged parts it of the gripping lines L-L, and the tail is draped on the opposite ends of the lines at t. The opposed gripping lines relatively separate at the shoulder zone 3 of a skin and converge to a narrow cross-zone r at the rump where the lines again bend apart at the tail edge zone '6. Thus the sinuous-line gripping means causes highest tension on skin at the neck zone h and at the rump r with less tension at the flank or shoulder s and the tail edge It.

What is claimed is:

1. In a leather stretching machine, a pair of slides movable into juxtaposition so that a sheet of skin may be draped thereover to distally opposite edges of the slides, and means along said edges whereby to grip longitudinal zones of the sheet with pressure the degree of which gradually diminishes from the longitudinal center of each gripping means; said slides being forcibly separable to stretch the sheet portion extending between the slides.

2. In a leather stretching machine, a pair of cooperative slides having opposite outer edges and provided with means at each of said edges whereby to grip elongate zones of a skin draped over the slides to said edges when they are juxtaposed,'with a pressure, in each slide, which is of difierential degree in the length of the gripped zone.

3. A machine as in claim 2, the pressure being of decreasing degree endwise from the longitudinal center of each gripping means.

4. A machine as in claim 2, said means forming a transverse bridge in the leather along the said zones.

5. A machine as in claim 2, said means forma transverse bridge in the leather along the said zones, and the pressure being of decreasing degree endwise from the longitudinal center of each gripping means.

6. In a leather stretching machine, means for differentially stretching leather in one operation from one edge to the opposite edge, including a pair of opposed, elongate gripping means to" receive spaced portions of a given skin and'having devices for gripping elongate zones of the skin with a line of constant pressure which varies along the gripped zone in each device; said grip ping means being relatively, forcibly separable while gripping the skin to efiect its elongation between said means.

7. A machine as in claim 6; said means transversely bridging the gripped leather in said devices.

8. A machine of the class set forth including a bridging device and a bridge presser device for stretching a sheet, and a pliant mantle disposed between the said devices and presenting an antifriction face to the traversing portion of the sheet being worked.

9. In a leather stretching machine, a back-rest including a basal part provided with spaced rows of independent cushions those in one row being staggered as to the other row.

10. In a leather stretching machine, a backrest including a basal part provided with spaced rows of resilient pads of differential compression resistance in each row.

11. A back-rest as in claim 10, and in which the resistance of the pads decreases toward each end of each row from the longitudinal center thereof.

12. In a leather stretching machine, a pair of gripping parts having cooperative gripping edges meeting on a sinuous line as to which the skin is slippable under pressure between the parts and which line is of such contour that the gripped skin is tensioned less at theshoulder zone and at the tail edge zone than at the neck and at an intermediate rump zone.

13. In a skin stretching machine a pair of relatively separable gripping devices each comprising cooperative pressure applying parts on portions of a skin draped from one device to the other; the presser parts of each device meeting on compound-curve lines, and the said lines of the opposite devices being symmetrically reversed.

14. In a skin stretching apparatus, a pair of laterally separable gripping parts presenting opposite, cooperative gripping line edges of ogee curvature in a plane.

CARL HUGO J OHANSON. I

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