US1977576A - Process for the manufacture of press - molded rubber footwear with high heels - Google Patents

Description

Oct. 16, 1934. H. c. 1.; DUNKER Q 1,977,576 S PROCESS FOR THE MANUFACTURE OF PRESS MOLDED RUBBER FOOTWEAR WITH HIGH HEELS Filed Dec. 28. 1931 pHK s.

Patented Oct. 16, 1934 A at/s76 PROCESS FOR THE MANUFACTURE OF PRESS MOLDED RUBBER FOOTWEAR WITH HIGH HEELS Henry Christian Louis Bunker, Helsingborg,

Sweden Application December 28, 1931, Serial No. 583,501 In Germany Januaryv 3, 1931 2 Claims. (01. 18'59) In pressure molding of rubber footwear, that is the pressing in pressure machines of raw cut rubber slabs or the like to the desired correctly formed rubber covering as, forinstance, of a rubber boot, sand shoe, or other shoe with a rubber under-portion and with a high, or relatively high, heel, one could as a matter of fact easily make the whole heel massive and of rubber. For instance, a sufficiently large block of rubber out side might be placed on the heel portion of the pressing last covered with the necessary fabric and rubber layers and submit it to the side molds which move inwards, convergingly on the last of the press machine during the pressing process and the sole mold moving downwardly on to the sole portion of the last to form the said rubber block into a massive high rubber heel. The heel would thus be shaped at the same time that the outer molds moving inwards towards the last press-mold the remaining rubber covering of the shoe. Should a shoe have only a moderately high heel, a solid rubber heel would be too heavy, and in practice one cannot, there% fore, follow the above described mode of manuiacture of the heel by pressing a. suitably large rubber block into heel form. A press-molded rubber footwear may also be provided with a heel set thereon later, the said heel consisting contingently of partly vulcanized rubber. Such a stuck-on heel can be molded separately and can therefore if desired be provided with inner cavities. To make heels lighter by means of inner cavities is impossible in footwear made by pressmolding as it is not possible to mold the heel out of a rubber block with inner cavities, without decreasing the durability of the footwear. The present invention relates particularly to a proc: ess for manufacturing press-molded rubber footwear with high heels and its characteristic feature consists therein that thepressing last intended to be inserted into the press not only is covered, as usually, with lining material and the unvulcanized press-rubber to be pressed so as to form the sole and side covering of the finished footwear but that furthermore a heel blank, consisting of an inner core or filling body of a light, structureless material capable of resisting pressures and outwardly of unvulcanized press-rubber placed on the core, is applied to the press last. The invention relates also to the said heel filling body or core which is characterized in that its shape corresponds only very approximately to the shape of the outer face of the rubber heel to be pressed and that its material is light and has no tendency to break along special surfaces of fracture, even if it is exposed to pressures un-'- evenly distributed over the surface of the body. According to the invention a light and preferably stiff filling body is used for the manufacture of pressmolded rubber footwear withhigh heels,

as for rubber boots or shoes with only partly rubber-covered sides, the shape of the said filling body corresponding only partly and incompletely to the shape of thefinished pressed heel, whereby ing light and fracture free along planes of frac r ture, must be of such a kind that it gives off no gas or water vapour during the pressure-molding taking place at high temperatures. The filling body can be made out of a suitable mixture of wood cellulose (sulphite mass) and rubber, or

other similar mixtures, such as a mixture of leather waste and rubber. Other materials may enter into the given mixture, it being only necessary for the construction of the mass that it is possible to press and shape therefrom a heelfill ing body which can resist the pressure, even if this is very high and unequally distributed. The figures of the accompanying drawing show partly how the filling body may look and partly how it is covered outside with unvulcanized rubber. Finally the figures show the method wherein a canvas shoe with rubber under-portion and a high heel is pressed in a pressing machine during the press-molding of the rubber. Figs. 1 and 2 are perspective views of a constructional form of the heel filling body, Figs. 3 and 4 are perspective views of another constructional form of the heel core, Fig. 5 is a perspective view of one of the heel filling bodies represented in Figs. '1 and 3 covered with outer rubber to be pressed, Fig. 6 is a plan view of the filling body represented in Fig.

5 seen from the side which should lie against the sole of the shoe, Fig. 7 shows diagrammatically a side view of the press last covered with the canvas shoe and the pieces of rubber to be pressed. The canvas shoe itself and the filling shows diagrammatically how the side molds are 0 'Zil moved on to the covered last. The heel filling body 1, Figs. 1-4., 6 and '7, consists of a block pressed out only very approximately to the form of a heel and made out of a suitable material, such as wood cellulose, leather waste or other corresponding light fibrous material, and the said materials or fibres are stuck together in the mass by rubber or another suitable cementing material. If desired light filling materials may enter into the material from which the heel core 1 ismade. The filling body shown in Figs. 1 and 2 is provided with rather sharp edge faces, whereas the edge faces of the corresponding filling body shown in Figs. 3 and 4 are more rounded particularly on that side facing the tread of the heel. Fig. 5 shows how the filling body 1 is coated on its upper side, as seen in Figs. 1 and 3, with a sheet 2 of rubber to be pressed. In a similar manner the sides of the filling body are: coated with a strip 3 of rubber to be pressed. Fig. 6 shows the filling body seen from the sole side and shows how the strip 3 surrounds the sides of the filling body. The shoe upper itself can be made of leather, canvas or several layers of canvas with intermediate rubber layers (combined canvas) or of any suitable type of fabric. The press-molding of the rubber shoe is prepared in this manner that first the sole surface of the last 4, Fig. '7, is covered with an inner sole 5 which consists of lining material faced on the side away from the last with rubber. Then a part 6 is drawn on to the last, the part 6 being for the sake of clearness indicated in Fig. 7 partly in section and partly dotted and forming the lining in a footwear entirely covered with rubber (as, for instance, a galosh or rubber boot) in contrast with which in a footwear the sides of which are only partly covered with rubber (as, for instance, sand shoes or the like) it forms the whole upper portion of the shoe. If the part 6 has a buckle or strap piece 7 this is fastened tightly round the last. The rim of the outer side of the inner sole 5 which is put on to the last is painted with adhesive rubber, and therefore the edge of the part 6 can be pulled and bent round the edge of the inner sole 5 either by hand or by means of tongs and be stuck on to the outer side of the same. Then the rubber-covered filling body 1 is placed in position on the heel portion of the inner sole on the last and the front portion of the inner sole is covered with the outer sole sheet 8 of rubber to be pressed. Finally a rubber band or rubber ring 9 is laid round the under-portion of the last i, turned upwards in Fig. '7, which provides the rubber to be pressed for the rubber galoshing with which it is desired to provide the footwear. When the last is covered in the said way, it is set into the pressing machine, and the machine is put into action with the result that the sole mold 10, Fig. 7, descends towards the last, while the side molds 11, Fig. 8, are moved inwards towards the last. When the outer heated molds 10,11 have reached their innermost position the rubber portion of the footwear is pressed to the desired form, partly by means of the sole mold 10, which presses the outer side of the sole and the front edge and bottom of the heel, and partly by means of the side molds 11, which press the sides and rear portion of the heel and the low rubber galoshing which is indicated by the dotted line 12 in Fig. 7. The superfluous rubber is pressed out from the cavity formed by the outer molds in their innermost position. It is pressed out between the edges of the molds meeting one another and along the cutting edges of the molds which define the-rubber galoshing along the line 12 in Fig. 7 and can simply be torn oif later. The invention is not restricted to the forms of heel filling body set out in the drawing, as this need only be formed as a suitable block of considerably smaller dimensions than the finished rubber heel. The filling body 1 can either be cut out or molded. The latter is generally preferred, and the molding takes place in some kind of press so as to compress the mass of which the filling body consists.

I claim:

1. A process for manufacturing rubber footwear with high heels having a filling body in the heel in a pressing machine with heated outer molds and a press last consisting in placing the materiai to form the inner sole and the top part of the footwear or the side lining thereof on said press last, applying non-preformed rubber pieces about said material adapted, when reshaped by said molds, to form the outer rubber of the footwear, placing the filling body of the heel in position, covering the lateral surfaces and the surface of said filling piece which is turned away,

from the last with raw cut non-preformed rubber pieces,applying said heated molds to the first and second mentioned rubber pieces to cause the several pieces, in a single step, to assume the correct shape of the outer rubber of the footwear and of the outer rubber of the high heel.

2. A process for the manufacture of rubber footwear with high heels having a filling body in the heel in a pressing machine with heated outer molds and a press-last consisting in applying the material to form the insole and upper portion of the footwear or the side lining thereof to the press-last, placing the filling body of the heel in position, placing raw out non-preformed rubber pieces around the heel core and the material placed on the last, and employing said heated molds to affect the said rubber pieces in order to Hi HENRY CHRISTIAN LOUIS DUNKER.

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