Patent Application
20080034566
The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.
As illustrated in
In step S10, a number of tough holes 21 are provided in the middle of the belt 2 by stamping. These through holes 21 are also used for positioning and guiding the subsequent process.
In step S20, a first residual slot 22 is formed by stamping between every two adjacent through holes 21. The first residual slot 22 has a shape similar to a sandglass.
Then, in steps S30 and S40, a second residual slot 23 and a third residual slot 24 are formed by stamping in the two regions between every first residual slot 22 and the two edges of the belt 2 respectively. The second and third residual slots 23 and 24 are shaped so that a hexagonal ring 25 is formed around every through hole 21. A ring 25 is still connected to the two edges of the belt 2 and the adjacent rings 25 by a number a legs 26.
In step S50, the lower mold 5 is used to forge six wedge planes 27 running continuously around the bottom surface of a ring 25. In the mean time, the upper mold 4 is used to forge six ridges 28 radiating from the through hole 21 to the surrounding first, second, and third residual slots 22, 23, and 24, respectively. The residuals produced by the forging are diffused to the through hole 21 and the first, second, and third residual slots 22, 23, and 24. Please note that the legs 26 are connected to the centers of the outer edges of the six wedge planes 27 respectively.
In step S60, a through hole 29 concentric to the through hole 21 but having a lager aperture is formed by stamping. The through hole 29 is the inner hole of a washer to be produced by the present invention.
Then, in step S70, the major shape of a washer is formed by stamping from the bottom around a through hole 29. Please note that the washer is still connected to the belt 2.
In stop S80, the upper and lower molds 4 and 5 are used to fine tune the washer so as to obtain the precise form factor, dimension, and levelness. Finally, in step S90, the formed washer is separated from the belt 2 by stamping.
The present invention has a number of advantages. First, the method is simple and, especially with the through holes 21 used for guiding, the investment on the molds can be significantly reduced. Secondly, in the foregoing embodiment, the wedge planes 27 are formed at the bottom surface and the method is thereby able to provide significantly improved yield as the washers are precisely positioned by the mold and the wedge planes 27. Thirdly, the legs 26 are connected to the centers of the sides of the washer which are places less prone to the deformation of the washer. This again helps improving the yield of the present invention. Additionally, after the first, second, and third residual slots 22, 23, and 24 are stamped, the hexagonal shape of the washer is basically formed, facilitating the subsequent forging and the dispersion of the residuals.
It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.
While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.
