Lower mold assembly for punching a sheet

Abstract

A lower mold assembly for punching a sheet comprises a lower mold body having an upper surface; a V shape trench is formed at the upper side of the lower mold body; each lateral wall of the trench being formed with a recess; each recess being installed with an elastic element; a punching knife being installed above the lower mold body; the hardness of the elastic elements being slightly smaller than that of the lower mold body; wherein the elastic element serves to increase the tightness in punching operation and to avoid the punching traces in punching operation. A width of the lower mold body is adjustable based on a width of a sheet placed thereupon for punching. The elastic element has an irregular surface. The elastic element is made of a material selected from one of POM and elastic hard rubber.

Description

FIELD OF THE INVENTION

The present invention relates to punching operations, and particularly to a lower mold assembly for punching a sheet, wherein installation of the elastic elements makes no plastic pad being used in punching operation. The safety of the operator is assured. The thickness of the sheet is not confined so that the production time can be reduced.

BACKGROUND OF THE INVENTION

Referring to FIG. 1, the prior art punching device is illustrated. In the prior art, a lower mold seat 10 has a mold assembly 11 thereon. A plastic pad 13 is placed upon the mold assembly 11. A folding portion of the mold assembly 11 is embedded with a folding knife 12 which can move longitudinally. The mold assembly 11 can punch sheets S to be folded so as to have a desired folded shape. The above mentioned structure makes the sheets S have no punching traces. Moreover, in the prior art, a plurality of plastic pads 13 must be prepared for suiting for different kinds of sheets S.

Then the sheets S are shifted for punching at another positions and thus the position of the plastic pad 13 is changed to avoid to generate punching traces in the operation. However, above operation is based on the skilled technology of the operator, while the safety and production efficiency are very low by users.

SUMMARY OF THE INVENTION

Accordingly, the primary object of the present invention is to provide a lower mold assembly for punching a sheet, wherein installation of the elastic elements makes no plastic pad being used in punching operation. The safety of the operator is assured. The thickness of the sheet is not confined so that the production time can be reduced.

To achieve above objects, the present invention provides a lower mold assembly for punching a sheet. The assembly comprises a lower mold body having an upper surface; a V shape trench is formed at the upper side of the lower mold body; each lateral wall of the trench being formed with a recess; each recess being installed with an elastic element; a punching knife being installed above the lower mold body; the hardness of the elastic elements being slightly smaller than that of the lower mold body; wherein the elastic element serves to increase the tightness in punching operation and to avoid the punching traces in punching operation. A width of the lower mold body is adjustable based on a width of a sheet placed thereupon for punching. The elastic element has an irregular surface. The elastic element is made of a material selected from one of POM and elastic hard rubber.

The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the prior art punching operation of the present invention.

FIG. 2 is a perspective view of the lower mold body of the present invention.

FIG. 3 is an exploded schematic view of the lower mold body of the present invention.

FIG. 4 is a schematic view showing the operation of the present invention, where the punching operation is not performed.

FIG. 5 is a schematic view showing the operation of the present invention, where the punching operation is performed.

DETAILED DESCRIPTION OF THE INVENTION

In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims.

With reference to FIGS. 2 and 3, the structure of the present invention is illustrated. The present invention has the following elements. A lower mold body 2 has an upper surface. A V shape trench 21 is formed at the upper side of the lower mold body 2. Each lateral wall of the trench 21 is formed with a recess 20. Each recess 20 is installed with an elastic element 200. A punching knife 12 is installed above the lower mold body 2. The hardness of the elastic elements 200 is slightly smaller than that of the lower mold body 2. The elastic element 200 may be made of POM or high elastic rubber material. The elastic element 200 serves to increase the tightness in punching operation and to avoid the punching traces in punching operation. Moreover, the noise in punching operation can be reduced.

Referring to FIGS. 4 and 5, the sheet is placed upon the lower mold body 2. The apex of the elastic element 200 is higher than the upper side of the lower mold body 2 and the surface B of the elastic element 200 is in contact with the sheet S at points P. When the sheet S is punched by the punching knife 12, the elastic elements 200 will provide sufficient elasticity to the sheet S so that no undesired punching trace generates in the surface of the sheets. This is because the point P provides sufficient buffer effect to the sheet S so that the points P′ has no punching trace.

Advantages of the present invention will be described herein. The installation of the elastic elements makes no plastic pad being used in punching operation. The safety of the operator is assured. The thickness of the sheet is not confined so that the production time can be reduced.

The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A lower mold assembly for punching a sheet; the assembly comprising: a lower mold body having an upper surface; a V shape trench being formed at the upper side of the lower mold body; each lateral wall of the trench being formed with a recess; each recess being installed with an elastic element; a punching knife being installed above the lower mold body; the hardness of the elastic elements being slightly smaller than that of the lower mold body; wherein the elastic element serves to increase the tightness in punching operation and to avoid the punching traces in punching operation.

2. The lower mold assembly for punching a sheet as claimed in claim 1, wherein a width of the lower mold body is adjustable based on a width of a sheet placed thereupon for punching.

3. The lower mold assembly for punching a sheet as claimed in claim 1, wherein the elastic element has an irregular surface.

4. The lower mold assembly for punching a sheet as claimed in claim 1, wherein the elastic element is made of a material selected from one of POM and elastic hard rubber.