Metal deforming – Process – Deforming sheet metal
Reexamination Certificate
2000-11-21
2002-11-05
Larson, Lowell A. (Department: 3725)
Metal deforming
Process
Deforming sheet metal
Reexamination Certificate
active
06474128
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for folding over a plate, and particularly to a method which minimizes generation of harmful detritus.
2. Related Art
In the process of stamp-forming a plate, various methods for folding over a plate are used. A conventional method for folding over a plate is shown in
FIGS. 4A-4C
. A notch is dented into the plate at the place to be bent, as shown in step
11
. The depth of the notch is approximately equal to half the thickness of the plate. Then the plate is bent 90 degrees at the notch, as shown in step
12
. Finally, the plate is compressed until both portions thereof closely touch each other, as shown in step
13
.
Another conventional method for folding over a plate is shown in
FIGS. 5A-5D
. A notch is dented in the plate at the place to be bent, as shown in step
11
′. The plate is bent 90 degrees at the notch, as shown in step
12
′. The plate is then bent a further 45 degrees, as shown in step
21
. Finally, the plate is compressed until both portions thereof closely touch each other, as shown in step
13
′.
Still another conventional method for folding over a plate is shown in
FIGS. 6A-6C
. A notch is dented in the plate at the place to be bent, as shown in step
11
″. A comer of the portion to be folded over is chamfered. The plate has a thickness T. Half of the edge of the plate at which the comer is located remains straight, thus defining a distance T/2. The arc formed by the chamfer has a 1.0 millimeter radius. The plate is bent 90 degrees, as shown in step
12
″. The plate is compressed until both portions thereof closely touch each other, as shown in step
13
″. During such compression, the chamfer helps reduce friction between the plate and a rammer which punches the plate.
FIGS. 7A and 7B
show a process of finally folding over a plate
50
, in accordance with the conventional method illustrated in FIG.
4
. The plate
50
is bent
90
degrees at a notch (not labeled) to form an upright foldedover portion
52
. An L-shaped rammer
40
moves in direction C. The rammer
40
progressively rubs a side wall
522
of the foldedover portion
52
, and thereby scrapes some hairlike chips and detritus
54
off of the side wall
522
. Such chips and detritus
54
can change the size of the plate
50
and can reduce the quality of the plate
50
.
Thus a method for folding over a plate which solves the above problems is desired.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a method for folding over a plate which results in accurate sizing of the plate.
Another object of the present invention is to provide a method for folding over a plate which minimizes generation of detritus harmful to the plate.
To achieve the above-mentioned objects, a method of the present invention for folding over a plate comprises the steps of: providing a first mold assembly to dent a notch at the place of the plate to be bent and simultaneously form a curved portion at an end of the plate which has a rounded comer with a 1.0 millimeter radius; providing a second mold assembly to bend the plate 90 degrees at the notch; and providing a third mold assembly to finally fold over the plate with a rammer acting on the curved portion of the plate and thereupon flattening the curved portion.
REFERENCES:
patent: 3-204124 (1991-09-01), None
Chung Wei Te
Hon Hai - Precision Ind. Co., Ltd.
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