Footwear heel piece shaper

Abstract: Footwear heel piece shaper, incorporating a mold (13), a pressing device and a leather stretching apparatus in the shape of a clamp that may be worked by a cylinder,wherein the pressing device (14-15) is attached to a block (6) crossing the upper end of two bars (1) and (2) held rigid in turn by a lower yoke or brace (4) and a bridge or brace (5) in the middle. The bars (1) and (2),are mounted with pivoting bearings (3) on which they are axially movable and able to tilt with respect to the bearings (3) from a vertical position in which the block (6) faces the mold (13) to a more horizontal position in which said block (6) leans back and is carried some distance from the mold (13).Easy access to the mold is thus allowed and the coupling and uncoupling maneuvers of the block (6) are facilitated.

Description: This invention is a machine designed especially for shaping heel pieces, that is, for molding heel pieces and adhering their counters, in all footwear types. The machine works equally well in the hot stage, that is, shaping and reactivating the adhesive, and in the cold stage of stabilizing the molding job; and it does all this in straight line production, stretching the piece while pressing it so that, combined with the preshaping provided by the way the cut leather piece is stitched, the process yields a whole shaped in three dimensions which holds its shape after the shoe has been completely made or stitched. As for any machine of this type, the goal is to speed up the operation and simplify task preparation so that the machine will be ready to use quickly, after replacing the mold. This way it fulfills the basic need of providing the sector with a means of operation that allows wider variation in styles without hobbling the production rate. In these days it is essential to keep the market moving with a dynamic of variety, quality and price featuring full optimization and short runs, reducing financial risks and increasing the possibilities of covering the expanding market of styles. The molding machine herein proposed is based on these conditioning factors and fulfills them, thanks to the innovations herein proposed, without abandoning the basic principle defining this type of machine. FORERUNNERS OF THE INVENTION A footwear heel piece shaper according to the preamble of claim 1 is known from DE-A-29 16274. Basically any machine for molding heel pieces and attaching counters is comprised of a mold, some apparatus for stretching the leather, and a pressing device which closes on the mold in order to shape the leather. The mold is a one-piece device, preferably made of metal, which may be heated and if necessary cooled; the stretching apparatus is comprised of parts engineered to go up/down; and the pressing device is comprised of a partially-enveloping cowl seated over the mold and the piece to be molded. This cowl acts after the piece has been stretched, press-molding it into shape. The machine can take any material the footwear manufacturer may use, and the shaping operation is given by the pattern and stitching, which are complemented by handling in which a counter coated with reactivatable glue is applied. As stated above, the mold is comprised of one solid part having the shape that is to be given to the finished heel piece. As a result, obtaining a countermold would be very difficult, costly and hard to use. This is why instead of such a countermold this invention uses the aforesaid pressing device, comprised of a partially-enveloping cowl whose interior contains an blow-up lining or membrane which, when filled with compressed air, exerts a uniform pressure all around the mold, adapting the leather laid out and stretched over the mold to fit the mold. Machines of this type are offered on the international market, such as those made by ZEUS S.R.L., MATIC S.R.L. and NORBA C.V., built in accordance with the state of the art described above. All these machines work on the same principle, incorporate two molds (one for the left foot and one for the right foot) and work first hot and then cold in an installation identical to the former. The hot stage, at a temperature between 60 and 180° C, shapes the piece and reactivates the glue; next the cold phase (and the quicker the cooling is, the better) stabilizes the new shape of the piece, and both the piece and its reinforcements or counters hold the shape thus acquired. The operation is always the same in all cases, regardless of the manufacturer: placing the piece on the mold, stretching the piece, hot pressing, releasing the piece, placing the piece on the cold mold, stretching, pressing, cooling and finally releasing the piece. In all cases the work is done with a vertical press which partially envelops the mold in operation, either because the press is lowered or because the mold is raised; the injection of air into the inflatable lining provides the pressure needed to shape the piece. The piece is unmolded by separating the partially-enveloping press from the mold, releasing the stretching apparatus and leaving enough access for human intervention. There are two technically valid ways of separating or opening the mold: raising the pressing device or partially-enveloping cowl, or else lowering the mold. Whether access to the mold is better or worse depends on how much each part is separated from the other, but this should not lead to the conclusion that the version giving the greatest separation is the best technical solution, because that increases the distance to be covered and therefore the machine's idle time while it is opened and closed. Furthermore it is unfeasible to resort to upgrading speed to solve this problem, because that increases inertia and the danger of human error in the operation tempo. That is why more advanced techniques take the form of machines which tilt the mold forward at the same time as they raise the press, so as to consume a minimum time while facilitating handling, leaving plenty of maneuvering space; but even so there are no fully optimized machines for molding heel pieces while attaching the proper counter. Speed of execution on the one hand and ease in operation on the other are not a goal worthy of pursuit in themselves. Fundamentally the highest demand is for quality, and no known machine attains flawless quality, because no known machine offers the possibility of achieving from the outset stretching in a direction that takes the stitched piece with its counter in place and adapts them perfectly to the variable spherical curvature defined by the mold, so that the leather is not subject to stress. Such stress later translates into warping when the shoe is subjected to use, that is, body heat and a constant combination of pulling, bending and twisting. Leather reacts to this use in areas subjected to different molding stresses by displaying warping premature to aging due to use, which users mostly attribute to malformations of the leather itself, to which must also be added some users' improper way of walking. Apart from the important effects of incorrect molding on finished footwear, a swing-down mold speeds up the operations of placing/removing pieces, making up for a substantial part of the costs involved in designing a press that allows the mold to move without skipping cooling, especially when this rise in costs is due to difficulty in construction in the case of hot and cold presses alike (though when the hot press is resistance-heated, the difficulties are smaller than when working with a cold unit). DESCRIPTION OF THE INVENTION The invention is a machine for molding footwear heel piece along with their counters, reactivating their adhesive, which solves all the above problems without ever demanding in exchange concessions in quality, effectiveness or ease in operation. The invention may be defined as a typical press for this function, with the fundamental feature of the fact that it is the press which withdraws from the mold, moving away to give free access and facilitate operations without sacrificing speed or safety. Thanks to this it simplifies the heat or cold application system, lowers its cost and renders it more reliable. The press is mounted on a pair of bars held suitably rigid. This bar assembly can move both up/down and tilt backwards, for which purpose each of the said bars is mounted on the machine's frame with a pivoting radial bearing. Complementarily, in accordance with another of the characteristics of the invention, the fixed mold not only may be regulated heightwise, as is conventional, but also features the special fact that it is mounted so as to pivot on the machine's frame by one end lying transversal to its axis of symmetry, so that this pivoting action, assisted by the stretching apparatus, allows the mold to be set at an angle of inclination with the classic stretching clamps. This angle of inclination will in turn center the spherical curvature of the heel with the press cowl, so that when the stretching clamps are adjusted the heel piece will lie uniform and under perfect control, and therefore the leather will be shaped under pulling stress and behave homogeneously when in use, without wrinkling or warping. In accordance with another characteristic of the invention, the clamps for stretching the piece may be oriented orthogonally, so that the position of the free sides of the leather piece to be shaped is at all times correct for the pulling force to be exerted, the shape the piece is to be given and the final pressing operation. In accordance with another characteristic of the invention, while the sequence of movements the press follows is always the same, the distance between it and the mold may be regulated. This achieves an important factor: to be specific, it balances the stresses between the sides of the membrane or lining housed inside the press head cowl and its center. This characteristic is vitally important, because the press exerts axial and lateral pressure since it works on the curve of the heel and its side faces, but the function of the press's down stroke is not to compress the heel piece but to reach a set distance between the mold and the internal part of the cowl; it is then the lining or membrane which exerts the necessary pressure. That is why being able to draw the press closer to or push it further from the mold will make the necessary pressure for shaping the stretched piece and ironing the seam be exerted on the heel. It must be emphasized that the pressure exerted by the lining is so strong that the press's bars, or rather the yoke or base holding them, must be locked into place so the pneumatic cylinder working it through the thrust bridge does not give way when the lining goes under pressure, and the pressure exerted laterally is roughly the same as exerted axially on the mold. DESCRIPTION OF DIAGRAMS To complement the description made herein and in order to help provide a better understanding of the characteristics of the invention, attached to this descriptive report as an integral part hereof is a set of diagrams depicting, as a mere non-limiting illustration, the following: Figure 1. This is a front side view of a heel piece shaper for all footwear types executed in accordance with the purpose of this invention. Figure 2. This is an enlargement, also in perspective, of the section of the machine bearing the mold and, of special note, the apparatus for working the pulling clamps for stretching the leather. PREFERABLE EXECUTION OF THE INVENTION In these figures it may be observed how the heel piece shaper proposed herein is built based on a pair of bars (1-2) mounted so as to tilt back and forth over the machine's body by means of pivoting bearings (3) in the middle. The aforesaid bars (1) and (2) are held rigid by a yoke (4) at the bottom, a thrust bridge (5) at the middle, and a block (6) at the top comprising the pressing device. This tilting structure is allowed to tilt by the yoke below (4), which is controlled by a pair of pneumatic cylinders (7) and (8), which tilt the bars (1) and (2) back and forth between two end positions, that shown in figure 1, which is the machine's inoperative position in which the mold is free, and that in which the block (6) comes down on the said mold in order to perform the aforesaid shaping. A pair of draw springs (9) make bars (1) and (2) tend to tilt into their operating position, acting like compensators of cylinders (7) and (8). At the same time, in the said operating position the bars are locked by stop catches (10) catching the yoke or brace (4). A vertical pneumatic cylinder (11) installed on top of an axial regulator device (12), which may take the form of a hydraulic cylinder or a spindle, for instance, is in charge of raising and lowering the bars (1-2), and thus it is in charge of coupling and uncoupling the block (6) and the mold (13). Since the pneumatic cylinder (11) is attached to the thrust bridge (5) between bars (1) and (2) by its rod (11a), when the regulator device (12) is worked, raising or lowering the cylinder (11), bars (1) and (2) also move, and consequently the block (6) rises and descends in a similar fashion. When this moving assembly is propelled vertically, it moves guided by the bearing (3). The up/down stroke is defined by the rod (11a) and is always run completely. It may be deduced from the above that the distance between the block (6) and the upper end of the mold (13) depends on whether the pneumatic cylinder axial regulator device (12) is extending or retracting; and that the piston's stroke and therefore the axial distance moved by bars (1) and (2) and with them the brace formed by the yoke (4), bridge (5) and block (6) is always the same. The aforesaid block (6) is equipped with a partially-enveloping cowl (14) in whose interior there is in turn a blow-up membrane or lining (15). When the bars assume a vertical position, the block (6) and cowl (14) assembly becomes operational. The mold (13) lies on a gooseneck rest (16) which is set by means of a shoe (17) onto the table (18) constructed around the machine's frame. Under this mold (13), on each side of the rest (16), there is a dolly (19). These dollies are connected to the housing (20) of the clamp mechanism (21) by means of an arm (22); the housing (20) may be adjusted orthogonally and radially, so that the dolly (19) may be lined up correctly with the mold (13), forming an outer surface whose curvature matches that of the mold and forming an extension of the mold with hardly a break in continuity. This dolly couples perfectly to the clamp (21), with the same curvature, so that when the said clamp closes on the leather heel piece, the leather adapts to fit the surface of the mold without stress. As may be observed especially in figure 2, the clamp housing (20) is positioned on a plate (23) which is in turn mounted on a head (24) whose height is regulable. This head comprises the upper end of the rod driven by a pneumatic cylinder (25) which is the driving element of the clamp and which, after closing the clamp, pulls on the leather heel piece, forcing it to stretch out over the mold. In accordance with one of the essential characteristics of the invention, this clamp drive cylinder (25) is attached to a plate (26) which can be tilted along its rear edge (27) with regard to the table (18). It is also furnished with a regulating apparatus (28) which can orient and stabilize the slope of the said plate (26) with respect to the horizontal and consequently the orientation of the cylinder rod (24) with respect to the vertical. This allows the direction in which the leather is stretched to be suitably oriented and therefore ensures that it is stretched under optimum conditions at all times. The assembly described above is applicable for both a machine with a heated mold (13) and a machine with a cooled mold. In accordance with this construction, the machine functions as follows: When the aforesaid pneumatic cylinders (7) and (8) are actuated, they allow columns (1) and (2) to go vertical or operational. In this situation the block (6) face the mold (13) vertically. At this time the actuation of the pneumatic cylinder (11) drags down the thrust bridge (5), and with it bars (1) and (2), and through them it causes the block (6) to descend and therefore couple onto the mold (13) with the leather heel piece in between. When the cylinder reaches the end of its stroke, the stop catches (10) catch the yoke (4) and immobilize the bar/yoke/bridge/block assembly. In this, the operating position of the machine, the membrane or lining (15) housed in the partially-enveloping cowl (14) acts, providing the proper pressure prior to a pulling or stretching of the aforesaid leather piece by the cylinder (25) pulling the clamp (21) in the correct direction. The following operation consists in lifting the block (6), leaving it hanging over the mold (13). Immediately thereafter pneumatic cylinders (7) and (8) tilt bars (1) and (2), pulling away the partially enveloping cowl (14) and leaving the mold (13) free in the position shown in figure 1, with ample maneuvering space for placing on the said mold (13) the already sewn leather heel piece with its matched counter. Further description is considered unnecessary in order for any expert on the subject to grasp the scope of the invention and the advantages stemming from it. The materials, shape, size and placement of the components may vary provided that such variations entail no alteration of the essence of the invention. The descriptive terms used in this report must be understood always in the broadest, non-limiting sense.

Claims: Footwear heel piece shaper, being of the type which incorporates a heated or cooled mold (13) on which the heel piece is laid with its counter, on which mold there acts a pressing device also incorporated in the footwear heel piece shaper consisting of a cowl (14) with its blow-up membrane or lining (15), and working with the above components a leather-stretching apparatus which is also incorporated in the footwear heel piece shaper in the shape of a clamp (21) that may be operated by a cylinder (25), characterized in that the footwear heel piece shaper comprises a block (6) crossing the upper end of two bars (1, 2) in turn held rigid by a lower yoke or brace (4) and a bridge or brace (5) in their middle, which bars are mounted with pivoting bearings (3) to tilt over a table (18) attached to the machine's frame, with respect to which table the mold (13) remains permanently motionless, the aforesaid bars (1, 2) being able to tilt with respect to the bearings (3) from a vertical position in which the block (6) faces the mold (13) to a more horizontal position in which said block (6) leans back and is carried some distance from the mold (13) allowing easy access to the mold, and furthermore the aforesaid bars (1, 2) being movable axially on the pivoting bearings (3) to facilitate the coupling and uncoupling maneuvers of the block (6), and more specifically for allowing the cowl (14) and its membrane or lining (15) to slide over the mold (13), said pressing device (14, 15) being suitably attached to said block (6). Footwear heelpiece shaper as set forth in claim 1 above, wherein the means of tilting bars (1, 2) includes a pair of pneumatic cylinders (7) and (8) connected to the lower yoke or brace (4), each of which works with a draw spring (9) which acts as a compensator of each of the said cylinders, furthermore incorporating a pair of catches (10) which lock the aforesaid lower yoke or brace (4) in the operating position. Footwear heelpiece shaper as set forth in claim 1 above, wherein the means of axial movement for bars (1, 2) incorporates a pneumatic cylinder (11) whose rod (11a) moves the thrust bridge or middle brace (5) connecting bars (1, 2) up and down, with the special feature that the aforesaid pneumatic cylinder (11) rests on an axial regulator device (12), which may take the form of a spindle or a hydraulic cylinder, and through which the distance between the block (6) and the mold (13) is regulated, regardless of whether these components are coupled or uncoupled, which may be done in any case by a full stroke of the pneumatic cylinder (11) connected to the thrust bridge (5). Footwear heelpiece shaper as set forth in the claims above, wherein the mold (13) is set on the table (18) by means of a gooseneck rest (16) and a shoe (17), with dollies located on both sides of the aforesaid rest (16), each dolly (19) joined to the housing (20) holding the clamps (21) by an arm (22), and this housing (20) lies on a plate (23) which in turn lies on a regulable head (24) driven by a pneumatic cylinder (25) by means of which the leather is stretched, with the special feature that all these moving parts--dollies (19), clamps (21) and drive cylinder (25)--are mounted on a base plate (26) which is in turn mounted on the table (18) by means of a rear transversal-tilting shaft (27), and working with the said tilting plate (26) there are regulating and fixing apparatuses (28) stabilizing the said plate in any position or slope chosen for it as the best in each case for properly orienting the direction in which the clamps pull on the leather heel piece. Footwear heelpiece shaper as set forth in the claims above, wherein the dollies have a curved outer surface matching the outer surface of the mold (13) of which they are an extension with hardly a break in continuity, and furthermore the jaws of the clamp include gripping surfaces with the same curvature as the dolly, such that when the clamp closes on the leather heel piece, the heel piece adapts to the surface of the mold without stress.

Inventors: PRIETO VICENTE FALCO, PRIETO, VICENTE FALCO
Applicants: TECNIFAMA S L, TECNIFAMA, S.L.
Application year: 1992
Main classification: A43D11
IPC codes: A43D11, A43D25, A43D21