CA1126911A - Machine for stiffening and forming sheet material - Google Patents

Abstract

Abstract of the Disclosure A machine for stiffening and forming a selected area of flexible sheet material, for instance an end portion of a shoe upper, comprises work support mechanism including a universal female preformer having work-accommodating dihedral surfaces, an applicator for depositing on a portion of the selected area a predetermined volume of molten resin substantially in proportion to that area, and a presser complemental to the cavity defined by said surfaces and relatively movable into and out of cooperative work-pressing relation with respect to the work support to spread the molten resin and impart appropriate thickness gradient thereto throughout the selected area whereby, upon cooling, it is formed three-dimensionally and stiffened a desired degree in different portions.
For forming in-place end portions subsequently to be lasted, such as backparts of shoe uppers, pincers suitably control spreading and tensioning of the work and then relatively move with respect to the applicator to partially distribute the resin extruded in parallel arrangement within the area prior to shut-off of resin flow directed at an angle on the order of about 45° to the area. Thereupon, the applicator being retracted, the molten resin is fully distributed throughout the selected area by mechanism closing the dihedral surfaces normal to the adjacent presser thus avoiding wrinkling and/or scuffing of the shoe upper and disturbing the distribution, in thickness and laterally, of the still molten resin.

Description

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This invention relates to a machine for preforming and stiffening flexible sheet material. It is particularly concerned with providing improved machines for forming and stiffening upper materials constituting the end portion of footwear. Accordingly, in one aspect, this invention ;s directed to irrlpl(!ment,ltiOn Or the methocl for l'ormin~ in situ therrnoplastic counter S portion6 flS diBC1oBed in (,'anadian Patent No. 1,075,412 issued on April 15, 1980. It will ~e understood that usage of the present invention is not limited to footwear manufacture although this field will herein ~erve for purpo~e~s as illu~3tration of the invention.
It has long been an objective in shoe making to shape and stiffen 10 end portions of shoe uppers. As regards their bf1ckpart~:, Eor in.s~:nrlc(?, counterff have been prc)vi(lecl for thi~ purr)ooc. 'I'hey ~Ire ext)cn~Jive~ costl~y to infftall arld necessitate rnaintairling an inventoty of si~,es ancl .qtyles.
Moreover, counters seldorn truly conform l'or long to the last or Eoot shar)e, bre~llcing clown in ~ervice and perhap~; consequently resulting in di.scornf'ort 15 in wear ~nd/or un~iatisfactory appeararlce and shortened usefu] life. Toe portion~i of vamps h~ve been stiffened, J'or example, by the use of thermoplastic applied as disclo6ed in IJ. S. Patent Nos. 3,945,074 and 4,063,527 to mention only tvwo of many.
In the prior Rrt thel e have been attempts to inject stiffening adhesive ~6~

between an extremity of shoe upper and a liner or insert while placed over a last. In general such "one-shot" approaches have not been commercially acceptable largely for the reason that they lack the nice control required to produce the ultimate required shapes. The opposite sides of uppers 5 alone may dif:Eer in thickness by as much as . 040", and upper and lining combinations have thickness variation of up to about .060"; such non-uniformity raises very difficult if not impossible problems for a purely rigid mold shoe forming system. It will be ~ppreciated, for instance, that in addition to catering for sizes, counter portions should be thicker 10 in the back seam region and along the base region but then taper to a much rl duced thiclsneas alon~,r the top line of the upper ancl at the outer wing portions. The present invention accordingly recognizes the desirability of a two-stage solution, i.e. (1) introduction of thermoplastic resin to the preliminarily formed work with suitable distribution to be more completely 15 effected by substantially universally applicable cooperative preforming and related implements, the main subject of the present invention, and

(2) transition of the assembled upper, ~nd prefer.~bly (though not ne( e~sarily) while the resin is ~t:ill molten, lor l~ )ting in n ~luitllr)le (Idj(lcent mac}line (Lor instance oL the b~ckpaIt molding type di~clo~;ed in ~ . L,etters Patent 20 No. 3,0~6,531) to impart final conforming shape to the stiffened upper placed on its l~st. ~uch two--stage making of shoes, as well as other products to be ~ liLarly stiïfened and formed, is advlntageous ~rom a practical standpoint in that the Lirst stage can be perforrned rnore quickly than the second and a coo]ing or dwell period is desirable in the latter to insure that depo.sited resin is not 25 adversely redistributed. It is desirable that the upper "remember" its final ~ 9~1 conforming, but not its preforming in the initial stage.
In view of the foregoing it is an object of this invention to provide an improved machine for stiffening and forming flexible workpieces by depositing molten thermoplastic thereon, the machine to incorporate closeable preforming 5 means of a universally applicable type for controlling further distribution of the thermoplastic.
A general object as regflrds the shoemaking art is to provide a machine for applying molten thermoplastic resin to a selected area of an upper of f its last and then further distributing the resin in place upon a larger surface 0 of the upper, including the selected area, to be desired, usually tf1pering, thickness in readinetjs for laHting.
Another and more speciLic object of the invention is to provide a highly productive maehine for stiffening and preforming back portions of shoe uppers by application of molten resin in situ.
Yet another object of this invention is to provide an off-the-last baekpart upper forming machine having a resin injection applicator and substantially universally applicab]e preform mechanism with cooperative upper controlljnrr means for preparing the upper ecc)nomicfllly lor lufltillrr o~)eralions on its lust .
To these ends l;he invention comprises the combination with convent;onRl thcrmop]astic resin injection means of a novel applicator, work supporting means comprising universally applicable mflle and female preforming mechanism, and work spreading and tensioning mc~ans under the control of an operator for effecting distribution of the molten resin in cooperation 25 with the forming mechanism. Preferably and as herein shown the illustrative .

machine comprises a pincer for seizing the upper at its toe end, and a pincer for gripping the upper at its heel end along the upper edge of its back seam, the work being thus suspended initially with its lining, if any, retracted to an out-of-the-way position to admit the nozzles of a molten resin applicator to a resin delivery position With bottom edges of the upper suitably spaced in the cavity defined by the female :~ormer and equally tensioned, and the lining held open, injection is commenced while the top or toe pincer li:lits the work to hold it against the applicator. Nozzle orifices, some of which may be blocked off when unneeded, preferably have their axes directed 10 at an angle of about 45 to the adjacent work surfaces to be coa.ted to prevent nozzles being i:oul.ed by deposited resin. During ejection of the predetermined charge of molten resin in adjacent globules, the back seam pincer is retracted relative to the applicator to elongate the coating heightwise of the shoe a.nd sub6tantially in equal volume on opposite sides of the back seam. Now the 15 operator (or a wiper mechanism if and when preferred) may return the lini.ng to its normal outspread counter pocket position against the upper and relatively actuate the male and female formers to more fully distribute the molten resin. The arrun~,relrlerlt utlvarlta~eou~ly i~3 ~uch thut the male rormer or preHser initially is moved downwardly into a V-shaped cavity 20 defined largely by dihedral sides of the female former. The sides may be h:inged at the buclc seam locality by u foam insert or self-adjusting filler but this i.s not required . With the male presser positioned close to or in light contact with the lining, the dihedral sides are moved inwardly substantially normal to the adjacent presser surfaces thus avoiding wrinkling of the upper S and adversely affecting distribution of the resin be-tween the preforming ,.

- s -members. While the toe pincer is tensioning the stock upwardly about the presser with a controlled pressure, closure of the formers is effected for a selected dwell. At expiry of the time delay the forming mernbers separate and the pincers automatically release the upper flaccid with its distributed and still molten resin for transition to an adjacent machine such as the bacXpart assembling and molding machine referred to above for final shaping.
According to the above objects, from a broad aspect, the present invention provides a machine for preforming and stiffening a selected area of a shoe upper. The machine com-prise~ means including an applicator for thickly depositing a thermoplastic molten resin in a substantially central portion of the said area. Pincer means is provided and comprises a pair of spaced grippers for seizing different marginal localities of the upper to position it for reception of the resin. A pair of co-operative formers are closeable for engagement with opposite sides of the said area. The grippers are mounted for movement to spread the upper and tension it about a surface of one of the formers.
A mechanism i9 also provided for moving thereupon the other of the formers into closing relation with -the said one former and a side of the said area to complete distribution of the molten resin substantially throughout the area.
The foregoing and other features of the invention, together with novel details and combinations of partsl will now be more particularly described with reference to the accompany-ing drawings of an illustrative backpart upper preforming maching wherein a selected portion of the upper is both stiffened and formed off-the-last, wherein:
Figure 1 is a perspective view of the machine, with portions broken away, and showing in inoperative position a largely conventional thermo-plastic injection unit, an applicator, work supporting means in the form S of a pair of cooperative pincers, and closeable V-shaped universal preforming means for redistributing the molten resin deposited by the applicator;
Figure 2 is a view similar to Figure 1 and showing the machine at a next stage wherein the work, a shoe upper, has been positioned and is 10 receiving a charge of resin from the applicator;
FiKure 3 iY a perspective view taken from a different ungle to show the work as positioned by the pincers and their actuating means;
Figure 4 is a view sirr~ilar to Figure 3 and illustrating retraction of the heel end from the applicator to spread the resin deposit heightwise 15 of the upper;

Figure 5 is a perspective view similar to a portion of Figure 2 but on a larger scale to show the applicator retracted from the upper;
Figure 8 is a plall view ~howing C)n a lurKer HCale U CoUllter in l'lUtterled condition to illustrate its back seam and the plurality of elongated resin 20 deposits in a symmetrical, central area prior to closure of the preformers;
Figure 7 is a perspective view ~3imilar to Figure 5, but at a next ~tage of the operuting cycle wherein upper and lower formers have closed to further distribute the molten resin;

Figure 8 is an exploded perspective view of the preforming members;
Figure ~ is a view in elevation showing the fully lowered male former , .

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and the raised female former prior to closure;
Figure 10 is a view similar to Figure 9 and illustrating cam actuation of the sides of the female preformer in a direction normal to the presser; and Figure 11 is a representative timing chart for one cycle of the machine.
S Referring to Figures 1 and 2, an extruder-injector unit 20 of known type is mounted on a frame 22. The unit, briefly, includes a hopper 24 for receiving thermoplastic pellets P, for instance of a polyolefin such RS a polytheylene, to be melted when fed into an extruder barrel 26. A heated applicator 28, hereinafter to be further described, is arranged on one end of 10 the barrel to receive ancl emit a predetermined charge of the molten resin, designated 1~ in Figure~s 5 ancl ~, when applied. As herein shown, the unit 20 is secured on a carriage 30 horizontally slidable on the frame and toward and from a resin delivery position by operation of a piston-cylinder device 32, its cylinder being affixed to the frame and its piston being connectrcl to the carriage.
15 'rhe unit 20 comprises an injector cylinder 34 the piston rod of ~,~hich is reciprocated axially three times per cycle of the machine to insure that a full predetermined charge of the pellet~3 P iB HUpp~ d ;nto the injecti-)n c ylinder.
The arran~ement i8 such that actuation of n Htart switch on a control panel 3f;
to effect operation of the injector cyclinder 3~1 also pressurizes the cylinder 32 20 a~ indicated in the timing sequence shown in Figure 11. ~ccordingly, a selected predetermined volun~e of molten resin appropriate to the size and configuration of the work to be stiffened and shaped will be available to be extruded from the applicator 28 when it has advanced (to the right as seen in Fig. 2) and a piston-cylinder device 38 (Figs. 1, 2, 11) has been actuated to open a value 40 25 controlling resin flow into the applicator. The device 38 is thus actuated by a ' control circuit including a switch 42 associated with the device 32 and arranged to be operated by an abutment 44 affixed to the carriage 30.
It will of course be understood that an operator will not normally cause the resin R to be extruded until the work, in this instance a shoe S upper U having a liner L, has been properly mounted in the machine as next explained. Assuming it is the heel end of the upper which is to be stiffened and preformed preparatory to heel end assembly and lasting, the upper ia suspended as indicated in Figs. 2-4. It will be noted that the work positioning means and technique differs in detail in several respects I from that employed in the above-mentioned Canadian Patent No. 1,075,412 to better fucilitate control of the work in the successive stages of the cycle subsequently to be described. In the present disclosure the upper U is suspended from, and tension therein controlled by, a top or toe pincer 46 (Figs. 1-5 and 7) and a bottom or heel end pincer 48. Particulars of these lS pincers need not be fully detailed here, it being understood that they may sub6tantially correspond with fluid pressure operated equivalents found in the shoe lasting art.
For ~3upporting both Of the pirlcer~ und pin( er operating mecharliHm and work supportinrr means including universal preforming mechanism later 20 described, parallel uprights 50,50 are secured on the frame 22. The toe pincer 4~ is closeable to grip the upper U at the will of the operator (by actuation of a ~econd treadle, for instance, a firElt treadle controlling a limit value (not shown) and fluid preasure to the pincer 48 as indicated in Fig. 11 by means of piston-cylinder device 52 (Figs . 1-4) ), the toe extremity 25 preferably being notched or bearing suitable indicia to enable the operator conveniently to position the work in the jaws of the pincer 46 prior to their closure. It will be understood that the pincer 46 will have been positioned initially to properly accommodate the size of the particular work being processed. Longitudinal tensioning of the upper by means of the pincer 46 5 is controlled by actuation of a piston-cylinder device 53 (Figs. 3, 4, 7) .
For most work it is generally preferred that first the hacck seam adjacent to its upper edge be inserted into the bottom pincer 43 against a st-p (not shown) therein, as indicated in ~ig. 4, nnd then, aft.er pulling the bottom pincer upwardly by means of the upper U, inserting the toe of the vamp 1() into the open toc pincer 46 bcl'ore causing its closure. The timing .qhowrl in the c hart Or li`ig . :I. l indicate,s closurc! Gf the pincer 48 hy operation of the first treadle (not shown) prior to closure of the toe pincer 46 by actuation of the second treadle (also not shown), but this may, for some work, be a rnatter of choise left to the operator. CloFure of the pincer 48is controlled 15 by 1 piston-cylin(ler device 54. It is important that the operator ascertain at this stage that the supported upper be positioned with its bottom edges symmetrically dispoF,cd within thc cavity del'inc(l by dihe(ltal ir~rlcr .surflceti 56, 5G Or 1 I'erll~ll(`, Univ(!rt;~l tyl)C O~ltHide pr(~f'ormer ~rene:rally dc.9ignatecl 58 (~igs. t-5, 7~10) . The bottom edges should he equally 20 tensioned on oppo6ite sides of thc! back .searn. The prel'orm~r si~leF. 56,56 UL~e slightly con( ave heiglltwise of the upper ll and disposed with an included arlglec)rfrorrll5-75, more usually in the rflrlge ol' 30-60, and herein sh-)wn as about 45 . Concavity of the surraces 56, 56 about an axis substantially parallel to lengthwise work--engaging elements or edges such as at 60 of 25 the outside former has a radius on the order of about eight inche.s. The ~l~t~

preformer 58 has on its outer sides a kerf 62 arranged to slidably receive, respectively, a land or ridge 64 (Fig. 8) formed on the inside of an internally V-shaped block 66. The latter is movable heightwise by a piston-cylinder device 68 at a subsequent point in the cycle referred to later.
5 As shown in Figure 8, a keystone-shaped resilient member 70, of rubber for instance, is disposed at the bottom vertex of the forming cavity and preferably rests in a channel 72 formed in a bight or piece 74 yieldably supported on springs 76,76 confined in bores of the block 66. Angle guides 78 bolted to the frame 22 are alidably engageable with outer side walls of the vertically lO movable block ~6 which is in its down or inoperative position in the stages depicted in Fig~ 1-5.
With the work suapended aa above described the operator will hold the upper lining L, if any, retracted to an out-of-the-way position as shown in Fig. 2. He advances the applicator 28 and upward movement of the toe IS pincer produces contact or near contact positions of the nozzles 80 with the inaide back of the upper to extrude the reain R for deposit in thick, discrete bodies 82. These are emitted, one from each unblocked nozæle B0, onto the counter of the backpsrt in thicknesHes u9ul11y varyillg t'rom about 1/8" to

3/8", the grreater thickneas usually being in the locality of the back seam a9 20 indicated in Figs. 5 and 6. The nozzles are dispoaed in a subatantially V-shaped configuration, each having its axis directed outwardly to intersect the Hurface of the counter portion to be coated with an angle of incidence preferably of about 45 but generally acceptable within from about 30to 60. This arrangement prevents the deposited resin from "backing up" and 25 sticking to the nozzles, instead of ~:he upper upon withdrawal of the distributor body. For suitably adjusting the applicator 28 to accommodate smaller workpieces, it will be understood that short pins (not shown), or the equivalent, may be thrust into one or more of the wing nozzles to block their resin flow. Also means may be provided for retarding relative 5 movement of the applicator heightwise of the upper at the beginning and end of resin application to increase resin thickness in those localities if so desired.
In the course of depositing the molten resin R, which commences at localities in varying extent from the top line of the counter as shown 10 in Fig. 6, a carriage 84 (Figs . 3, 4 and 1 t) mounting the bottom pincer ~3 is automatically retracted to withdraw the upper backpart awsly from the applicator 28 thus to extend spreading of the bodies 82 heightwise of the upper. This is accomplished by a double-acting piston-cylinder device 86 operatively connected to the carriage and aids in keeping the l5 backpart wrinkle-free. The extruder cylinder 26 bottoms and resin flow is terminated prior to the tapering ends of the bodies 82 extending to the bottom margin of the counter. It has been found fIorn Mhoe ms1lcing experienee that the preliminary molten r(?sin di~tribution pattern urlcl ;ts substslntisllly symmetric arrangerrlent on the work as illustrated in ~ig. 6, is conducive 20 to the desired ultimate distribution of the stiffening ms,~terial to be slttained in the seque~ntial operations about to be clescribed. ~Si%e of the blobs deposited adjacent the upper margin of the upper is controlled by the start of nozGle retraction relative to the commencement of extrusion. :l~he diameters of intermediate portions of the blobs is controlled by the rate of noz~Gle r etracction 25 relative to the rate of resin extrusion. The terminal bulbous shape is controlled by the amount of extrusion after nozzle retraction ceases. As Figure 11 shows, the toe pincer 46 will preferably have exerted, during the resin depositing, some upward relatively light tensioning of the upper to draw its backpart snugly about the applicator. Upon completion of the S normal ejection cycle, a switch will be actuated to lower the toe pincer 46 after a time delay in which the applicator 28 retracts from the work.
The operator now restores the lining L to its normal position in the upper and thereupon actuates a switch to lower an inside presser or male former 90 from its inoperative position shown in Figs. 1, 2 and 5 to its I() operative relation with the upper us illustrated in Figs. 7, 9 and tO. It will be understood that alternate mechani6m for this purpose may differ greatly in detail. As herein shown the presser 90 is given a two-part motion, first to swing the presser about an axis extending above the upper and widthwiae thereof, and then to force it downwardly into close proximity 15 with the backpart of the upper in its forming cavity . For this purpose the presser 90, which corresponds substantially to the configuration defined by the surfaces 56, i8 detachably auaperlded l'rorn ~In ur m D~ curried centrfJlly by a cro~a urm 134 and actuated by us~ociflte(l linlcuge conrlected to ita opposite ends. For inauring tapered thickness and diminishing stiffness away 20 from the back aeam locality, the dihedral angle of the presser ~0 mfJy be roughly on the order of from 0 to 3 greater than that defined by the V-aurfaces 56, 56 . The arrangement ia such that a piston-cylinder device 96 operatively connected to each end of the cross arm swings the presser 90 from its inclined inoperative position shown in Figure 5 to a vertical 25 pOSitiOII shown in Eiigure 7 wherein the presser is close to but above the -~3-work in the forming cavity. Thereupon a piston-cylinder device 98 (Figs.
1, 2) operates, as indicated in Figure 11, to force the presser directly downward to position the exterior surface of the presser just above the inside counter (or equivalent) surface of the upper backpart. Simultaneously 5 with this final lowering of the presser 90, the bottom pincer 4~ r emains engaged with the back seam locality. It may be mentioned that in the particular arrangement shown a pair of constant pressure air cylinders 99, 99 (Figs .
1, 2) serve to aid in effecting upward return motion of the presser 90 near the end of an operating cycle.
I() At this stagc completion ol the descent of the presser 90 actuates E~ HWitCh which cEIu9e~ operation of mechanism to do two things: (1) the toe pincer 46, while still gripping the toe margin, is moved upwardly under a controlled pressure which may be different (usually higher) than that for previously tensioning the upper longitudinally, and (2) the device 15 6~ is energi~ed to move the block 6fi upwardly for the final preforming operation. In this latter resin spreading function it is sometimes p referred to effect raising Or the block 66 with a two-~.p( e(l techni(~ue, tlle Fnqter raisinl.f occurring lïrHt Elnd with rull line pre~J~Iure up to the point 11 in Figure 11. It is irnportant, of course, to accomplish the lElst phase of ~;tiffening 20 and preforming without wrinkling or scuffing the upper, yet completing di~tribution of ~;he molten resin 1~ throughout the baclcpart while insuring that, as thus (listributed, the resin will have an nppropriate tapering thickness from the thiclcer back seam area to the thinner marginal areas and at the wing extremities. I\s the block 66 is moved upwardly for this purpose 25 as indicated in E~igures 9 and 10, a pair of rolls 100,100 mounted one on ~12t~

each of corresponding edge portions of the preformer 58 is disposed to engage cam faces 102,102 respectively of cam 104 secured to the presser 90. The faces 102 each extend substantially 90 to the adjacent dihedral aurface 56. Consequently the reaction forces OI the roll and cam engagements S as the preformer 58 is urged upwardly serve to move the rolls inwardly as indicated in Figure 10 and to shift the preformer surfaces 56 inwardly and, importantly, in a direction substantially normal to the upper backpart to effect the completed resin distribution without risk of marring the upper as the preforming cavity is closed on the presser 90. Diagonal wrinkles lO near the top line of an upper, for instance, is an example of marring due to lorlgitudinul ~heur between the upper, resin, und lining. The arrangement specifically of the V-shape of the unlasted quarters joined by a back seam is of particular significance since it enables substantially universal accommodation of the short radii of curvature encountered in backpart extremities.
IS While for some work the presser and/or the preformer 58 may not need to be fitted with sealing means to retain the molten resin R wlthin desired bounds on the selected work area to be stiffened, it is ~enerally necessury (or at lea~3t desirable) to detE~chably mount El sealing 13trip 106 of suitable muterial orl the presser and customarily in ùlignment with its 20 bottom edge. The strip assures a clean bottom edge and prevents subsequent wiping of the resin into a lasting cement. The strip 106 may for instance, be of silicone-treated foam rubber backed by a thin metal band which is anchored at its upper ends and extends in selected ones of a series of grooves 108 spaced heightwise of the presser to position the strip parallel 25 to the bottom edge of the presser. Movement of the preformer 58 into its ~6~

cavity closing relation to the presser 90 initiates a controlled time delay to complete the spreading and joining of discrete hot plastic bodies 1~.
The delay and pressure are adjusted so that lowering of the preformer 58 starts practically coincident with buildup to selected ram pressure.
5 Longer dwells may cause the resin to creep outwardly with a "cold front"
that effects insufficient bonding. When the delay runs out, the preformer 58 is lowered and, on bottoming, lowering of the toe pincer 46 and raising of the presser 90 are initiated. Thereupon the top and bottom pincers are caused to release the upper for transfer, while the resin R is at least 1() partly molten, into the backpart assembling and la.~ting machine (or other l~r min~,t rnlchirle) wherein the upper will be rnounted on its last for I`inal forming .
Operation of the illustrative machine for preforming off-the-last a selected area, for instance the backpart of an upper, in a typical cycle l5 will now be briefly reviewed. It i8 to be appreciated that the technique practiced by the machine recognizes that -follow-on or final upper forming to the contours of a last will desirably be perrormed in n laF~t;ng ma( hine.
Mence, the depoflitf3 ol hot thermor)lllotic re~lirl r~rovitled by the ~)reE~ent mach;ne are of t3ubstantiu] initial thickness better to retain their rormab:le 20 condition for the required operating cycles of both machines . 'I he technique may be aided by provision of a controller for ~uitably regulating temperatl1re ol the forrrler s . F`or simplicity of de~icription, the lining retraction from normal position and its subsequent return after the depositing of the resin are herein assumed to be done manually.
The toe pincer being adjuste~ fore, aft and heightwise for the si7.e and positioning of the upper to be stiffened and preformed in its backpart, and the unit 20 being adjusted (as by pre-weighing each charge and operating at fixed intervals) for the volume of hot melt resin R desired to be extruded from the applicator 28, an operator inserts the back seam into the bottom 5 pincer. Another preliminary is to adjust the position of the sealing strip 106 heightwise of the upper if needed for a particular size. Then, pulling the now-closed bottom pincer upwardly by the upper, he inserts the toe end margin into the toe pincer, preferably being guided by a notch preformed in the vamp. 1~8 shown in Figure 11, a second treadle (treadle not shown, I() except in Fig. 11) is uctuated to cloRe the toe pincer 4~ and retract the back ~eum pince~r 98 to tensioll the upper lengthwise. Correct poaitioning of the upper in the pincers prior to resin depoYition and preforming i8 important as above mentioned. Though not herein shown, it may for some work be deRirable to provide u pair of auxiliary side pincers for seizing 5 the upper ut spaced points on opposite sides of the back seam pincer and alonK the top line of the upper thus to spread the work and exert a small, equali7,ed tension heightwiRe Or the upper lor positionin~ its bottom edKeH
relutive to the operuting path Or the prelormer ~8. ,Such uuxiliury si(le pincers may ulso facilitute entry of the applicator.
2() The next Ytage is to actuate the extruder unit 20, the applicutor 2n depositing molten reain in spaced, thick blob~ n2, preferably in symmetrical relation relutive to the top line aR shown in Figrure B. In Figure 11, the designation " I D" indicates usually preferred "time delay" intervals in the cycle. When the applicator 28 has entered the backpart "pocket", 25 the toe pincer lirts the upper to urge the backpart lightly against the periphery ~fi~

of the applicator. It will be observed that the back seam pincer 48 is retracted by its carriage 84 and actuated piston-cylinder device 86 during resin injection and applicator retraction, thereby elongating the resin pattern heightwise of the upper. The depositing is terminated within the selected S area ultimately to be stiffened and formed. Meaviest coating preferably occurs along the back seam. At the end of extrusion the toe pincer is lowered during applicator retraction. The preforming, first by tensioning the stock by pincer movement and then by closure of the presser 90 and the preformer 58 as will be described, is effective to thereafter diminish 10 the resin thickness taperingly toward outer edges of the backpart and towarcl the e~n(ll; or outer wings thereor. /\s has been noted the resin R
i3 applied to the work while suspended and with its lining, if any, removed to an out-of-the-way position. The angular incidence of the nozzles to the backpart, preferably about 45 prevents their fouling and aids in r esin IS deposition on the work.

After retraction of the applicator from the upper, the operator pushes the backpart lining clownwardly to restore it to its norrnal r)c)~;tion~ slnd then causes the pres~er 90 to opcrlte, in ~his instllrlce pcr l'orming a downwar d swin~,ring elfecte(:l by the dcvices 96, followed by VertiCR] descent into 20 the hackpart pocket and into light contact or near contact with the restor~d blclcpart lining I, as caused by the device 98. A limit valve (not ~;hown) is thereupon efl`ective to: (1) cause the toe pincer 46 to rlise thereby tensioning the backpart under controlled pressure against the presser 90, and (2) actuate the piston-cylinder device 68 to lift the preformer 25 58 by vertically elevating the block 66, either with single or dual speed approach. The dual speed is indicated in Figure 11 wherein the slower, less powerful forming force follows beyond the point P. The dihedral sides 56,56 of the preformer 58 are thereupon caused to close upon the backpart and adjacent side surfaces of the presser 90. Importantly, relative S closing motion of the sides 56 is effected substantially normal to the work by reason of the rolls 100 respectively engaging the cam faces 102. As indicated in Figure 10, the rolls 100 are thus moved inwardly to shift the sides 56 inwardly to a force balance position and at substantially rlght angles to each of the dihedral sides S of the presser 90. This lack of relative 10 sliding of the preformers with the work avoids scuffing the work or wrinkling it. ~t al~o enables the short curvature at the back seam locality to be imparted to the work as desired. The bight or piece 74 is not invariably required, though it appears to be vital when dealing with leathers where the pincer pull required to contain the resin under pressure would overstretch the 15 leather. At expiration of a time delay wherein the inwardly moved sides 56 have been closed on the preRser 90, distribution of the molten resin R between the lining L and the backpart of the upper will have been completed throughout the area to be Htitlened ~Ind with the thicknes~ taperin~ to a8sure the degree of ultimal:e Rtiffne~s desired in the different portions. Accordingly 20 the preformer 58 is lowered and, in re~ponse thereto, the toe pincer 46 and presRer ûO are raiE~ed. This signals for release of the upper from the pincers 46 and 48 whereupon the upper can promptly be presented to a heel end lasting machine while the resin R is still ~ufficiently molten for final backpart forming and coincidental lasting.
It will be appreciated that the sealing strip 106 will have been positioned heightwise of the upper on the presser 90 so as to assure that the outline of the fully distributed resin R is not only thinner adjacent to the top line, and hence of reduced stiffness, but also less visible in the finished shoe~
Temperature selection for melting the polyolefin used is controlled to eliminate 5 "strings" during depositing of the resin, and the pressure required for effecting distribution of the plastic can rernain essentially constant throughout usage of the V-preformers 58, 90, For resins tending to harden too rapidly, means may be introduced for heating the uppers and/or the formers.
Generally, no seals are needed at the wing ends, and a top seal to keep 1() the rcsin confined below the top line is optional.
lt will be understood Lrorn the oregoing that the invention provides a versatile machine to in situ forming and stiffening the end portions of workpieces such as uppers.
This application is a division of application Serial No.
15 329,593, filed June 12, 1979, for Machine for Stiffening and Forming Sheet Material, John G. Hollick the inventor.

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A machine for preforming and stiffening a selected area of a shoe upper comprising means including an applicator for thickly depositing a thermoplastic molten resin in a substantially central portion of said area, pincer means comprising a pair of spaced grippers for seizing different marginal localities of the upper to position it for reception of the resin, a pair of cooperative formers closeable for engagement with opposite sides of said area, said grippers being mounted for movement to spread the upper and tension it about a surface of one of said formers, and mechanism for thereupon moving the other of said formers into closing relation with said one former and a side of said area to complete distribution of the molten resin substantially throughout the area.

2. A machine as in claim 1 wherein said other of said formers has dihedral upper-engaging surfaces, and said mechanism is cam actuatable to urge said surfaces in a direction substantial normal to said area of the upper.

3. A machine as in claim 1 or 2 wherein said mechanism comprises a cam secured on one of the formers and displaceable means operatively engageable with said cam and mounted on the other of said formers to close them on the upper.

4. A machine as in claim 1 wherein said formers and at least one of said grippers are mounted for movement lengthwise of the upper, and said mechanism is operable in response to the lengthwise movement of one of the formers.

5. A machine as in claim 1 wherein the applicator and one of the grippers are relatively movable heightwise of the upper during deposition of the molten resin.

6. A machine as in claim 4 wherein said lengthwise movement of one of said formers is effected by a fluid pressure operated device having a yieldable vertex portion arranged to engage with the bight of said one former.

7. A machine as in claim 6 wherein. said device and said one former are formed with slidably interfitting guide surfaces.

8. A machine for stiffening the end portion of a shoe upper while imparting predetermined three-dimensional configuration thereto comprising mechanism including spaced extremity pincers movable to control the position and tensioning of the end portion, means for depositing on a central internal side of the end portion while suspended between the pincers a series of substantially interconnecting blobs of hot molten resin of predetermined volume, and presser means including a cooperative pair of male and female forming members relatively movable into and out of pressing relation to the suspended end portion to distribute the deposited resin while still molten as a coating throughout at least a major section of the end portion, said members having their work-engaging surfaces substantially V-shaped, the dihedral angle of the male member being greater by up to about 3°
compared to that of the female member whereby thickness of the end portion diminished from its end extremity and along opposite sides of the upper, and mechanism operable to further distribute the molten resin by forcing the work-engaging surfaces together without relative sliding movement relative to the upper or each other.