JPS6127951Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stretching device for stretching raw hides such as cowhide used as materials for power transmission belts into leather having a uniform thickness.

Conventionally, a device as shown in FIG. 1, for example, has been used to stretch raw hides. That is, in FIG. 1, reference numerals 1 and 2 represent a pair of plates, to which are fixed a number of clips 3 that engage the edges of the raw hide. Then, clip both edges 5 and 6 of the raw hide 4 to be stretched with clips 3 corresponding to each edge.
The raw hide 4 was then stretched by pushing the plates 1 and 2 apart from each other (in the directions of arrows A and B).

In such a conventional device, the clip 3 is connected to the raw hide 4.
Because they are attached at certain intervals, a uniform stretching force is not applied to the raw hide, and therefore the raw hide is uniform except when it has a uniform thickness and a rectangular or square planar shape. The disadvantage is that we cannot expect significant growth.

This drawback can be solved by, for example, determining the position of the clip through precise calculations according to the distribution of the thickness of the hide and the planar shape, and also taking into account the direction of movement of the board. Although it is thought that this problem can be solved, it is impossible to apply it to mass production, and in order to target all raw hides of all planar shapes,
Since it requires a large amount of experimentation, it must be said that such a method is impossible to implement from a cost standpoint.

The present invention is an attempt to solve the problems of the conventional device.The present invention consists of overlapping two rubber sheets that are easily stretchable and have a large frictional force on their inner surfaces, and a vacuum source is connected between the two rubber sheets. In addition to communicating with
The raw skin to be stretched is inserted here, and a pressing force is applied to the outside of one rubber sheet to stretch the overlapped rubber sheets into an arched shape, and the raw skin inserted between the two is stretched together with the rubber sheet. The feature is that it is made to do so.

Next, the present invention will be explained in detail with reference to the drawings.

In FIGS. 2 to 4, reference numerals 11 and 12 are rubber sheets, which need to be easily stretchable and have a large frictional force at least on their inner surfaces. Then, the rubber sheets 11 and 12 are stacked on top of each other, and the raw skin 13 to be stretched is inserted between them, and a vacuum source is communicated between the two sheets through the tube 14, so that the polymerization of both the sheets 11 and 12 is prevented. It is made even stronger, and the grip of the raw hide 13 by both sheets is made stronger.

Next, the entire periphery of the polymer of the rubber sheet is fixed to the workbench 20 with the fixture 21, and a pressing force is applied to the outer center of one of the rubber sheets 12 by the hydraulic device 22, so that the polymer of both rubber sheets ( The raw hide is held between both sheets), as shown in the fourth figure, so that it is curved in an arched shape, that is, the entire periphery of the polymer of the sheet is fixed, and a pressing force is applied to the outer central part. , stretching the sheet of polymer. As a result, the raw skin 13 sandwiched between the sheets is firmly sandwiched between both rubber sheets by the vacuum pressure, and since the inner surface of the rubber sheet has a large frictional force, the sheet is stretched into an arched shape. When this happens, it will extend with the sheet.

In this case, the raw skin is stretched by a tensile force acting on the entire surface of the raw skin, so that the raw skin is stretched uniformly.

In addition, in the above explanation, it was stated that when the entire periphery of the polymer of the rubber sheet is fixed and a pressing force is applied from the outside near the center of one rubber sheet, the polymer of the rubber sheet curves into an arched shape. However, it is obvious that it has an arcuate cross-sectional shape and is spherically curved three-dimensionally.

As described above, in the present invention, the raw hide is sandwiched between two rubber sheets, and a pressing force is applied from the outside so as to curve the rubber sheet into a spherical shape in one direction. Since the raw hides sandwiched between them are stretched, a uniform stretching force acts on the entire surface of the raw hides, making it possible to achieve extremely appropriate stretching.

It goes without saying that the term "rubber sheet" is not limited to one made of rubber, but refers to a sheet made of any material having properties equivalent to or similar to rubber.

[Brief explanation of the drawing]

Figure 1 is a schematic plan view of a conventional stretching device, Figure 2-
Figure 4 is a cross-sectional view of the leather stretching device according to the present invention.
Figure 2 shows the state in which the raw hide is inserted between the rubber sheets, and the third
The figure shows a state in which both rubber sheets are polymerized by communicating the space between the rubber sheets with a vacuum source, and Figure 4 shows a state in which a pressing force is applied to the polymer of the rubber sheet to bend the rubber sheet polymer into an arched shape, and a stretching force is applied to the raw hide. Each shows the state in which it acts. 11, 12...Rubber sheet, 13...Raw leather, 1
4...Pipe, 20...Workbench, 21...Fixing tool, 2
2... Hydraulic device.

Claims (1)

[Scope of utility model registration request] Layer two easily stretchable rubber sheets with at least a large frictional force on the inner surface, and use the space between the two rubber sheets as a place for inserting raw skin, and a tube communicating this place with a vacuum source, and a polymer of the rubber sheets. A leather stretching device that is equipped with a fixture that fixes the entire periphery of the rubber sheet polymer onto a workbench, and a device that applies pressing force outward near the center of the rubber sheet polymer.