Cutting – With control means responsive to replaceable or selectable... – Arithmetically determined program
Reexamination Certificate
2000-03-13
2002-05-28
Ashley, Boyer (Department: 3724)
Cutting
With control means responsive to replaceable or selectable...
Arithmetically determined program
C083S076600, C083S699510, C083S601000, C083S602000, C083S530000
Reexamination Certificate
active
06393954
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a work-cutting device, such as a right-angle shearing machine, for cutting a work, formed, for example, of sheet metal, using a fixed lower cutting edge and a movable upper cutting edge.
BACKGROUND OF THE INVENTION
A conventional work-cutting device is comprised of a right-angle shearing machine for using an L-shaped fixed lower cutting edge
42
and a movable upper cutting edge
41
extending along the inside of the lower cutting edge to cut a work W along a right angle direction P to obtain a rectangular piece Wb, as shown in FIG.
12
.
In such a work-cutting device, the upper cutting edge
41
is subjected to a reaction force F from the work W which is applied upon cutting in a direction reverse to that of a cutting pressure, as shown in
FIG. 14. A
lateral load Fa, a horizontal component of the reaction force F, flexes the upper cutting edge
41
and its support system to cause the upper cutting edge
41
to escape in a lateral direction of the work-cutting device, thereby widening the clearance between the upper and lower cutting edges
41
,
42
. That is, during lowering, the upper cutting edge
41
follows an upper-cutting-edge locus b that is laterally offset from an inherent upper-cutting-edge locus a, which is shown by the chain line in FIG.
13
. The amount of offset A between the loci a and b becomes maximum at a point of time during lowering when the cutting pressure is highest. A cut surface of the work W is located so as to correspond to the offset locus b.
Subsequently, once cutting has been finished, the lateral load Fa is eliminated to cancel the displacement of the upper cutting edge
41
, which thus elevate whiles following the inherent upper-cutting-edge locus a. At this point, since the cut surface of the work W is offset along the locus b of the upper cutting edge
41
which has been actually followed during lowering, the upper cutting edge
41
elevates while rubbing the cut surface of the work W hard. This rubbing wears the upper cutting edge
41
to reduce its lifetime.
Although a work-cutting device for adjusting the clearance between the upper and lower cutting edges during work cutting has been proposed by the applicant (for example, Japanese Patent Application No. 9-172260 (Unexamined Japanese Patent Application Publication No. 11-10437)), it does not take into account the prevention of possible rubbing during the elevation of the upper cutting edge.
It is an object of the present invention to provide a work-cutting device that can ease possible rubbing between the upper cutting edge and the cut work surface during the elevation of the upper cutting edge to prevent the upper cutting edge from being worn in order to increase its lifetime and that can avoid a possible upward warp of the work to maintain the processing quality.
It is another object of the present invention to enable possible rubbing during the elevation of the upper cutting edge to be prevented using simple control.
It is yet another object of the present invention to enable possible rubbing during the elevation of the upper cutting edge to be prevented using a simple control even if the upper and lower cutting edges are L-shaped.
SUMMARY OF THE INVENTION
An embodiment of the present invention will be described with reference to
FIG. 8
, which corresponds to a preferred embodiment. This is a work-cutting device for elevating and lowering a movable upper cutting edge
12
relative to a fixed lower cutting edge
13
, thereby cutting a work W, wherein the device has an upper-cutting-edge tight-contact avoidance means
10
for widening the clearance between the upper cutting edge
12
and a work cutting surface after work cutting has been finished.
According to this construction, after the completion of the work cutting, the upper-cutting-edge tight-contact avoidance means
10
widens the clearance between the upper cutting edge
12
and the work cutting surface, and the upper cutting edge
12
elevate with the clearance kept widened. Thus, even if the cutting surface is offset from the lower cutting edge
13
in a direction in which it leaves the lower cutting edge
13
, due to the escape of the upper cutting edge
12
upon cutting, the upper cutting edge
12
is prevented from being forced against the cut work surface during the elevation of the upper cutting edge
12
. Accordingly, the upper cutting edge
12
is prevented from being worn and thus has a long lifetime. In addition, a possible upward warp of the work W can be avoided to maintain the processing quality. To widen the clearance between the upper cutting edge
12
and the cut work surface after the completion of work cutting, the upper cutting edge may be moved so as to widen the clearance between the upper cutting edge
12
and the lower cutting edge
13
, or the position of the work may be adjusted without the adjustment of clearance.
According to the present invention, the upper-cutting-edge tight-contact avoidance means
10
comprises a clearance adjustment mechanism
22
for adjusting the clearance between the upper cutting edge
12
and the lower cutting edge
13
, an adjustment drive source
25
for driving this clearance adjustment mechanism
22
, and a clearance control means
35
for allowing the clearance adjustment mechanism
35
to widen the clearance between the upper cutting edge
12
and the lower cutting edge
13
after the completion of work cutting and before the elevation of the upper cutting edge
12
. The clearance adjustment mechanism
22
is comprised, for example, of an eccentric cam mechanism.
With this construction, simply by setting adjustment mechanism
22
for use in adjusting control means
35
using the clearance adjustment mechanism
22
for use in adjusting the clearance during cutting, as well as the adjustment drive mechanism
25
, the clearance can be widened after the completion of work cutting and before the elevation of the upper cutting edge, and possible rubbing can be prevented during the elevation of the upper cutting edge, using a simple control.
According to the present invention, the lower cutting edge
13
may have a generally L-shaped planar shape, and the upper cutting edge
12
may have a generally L-shaped planar shape extending along the lower cutting edge
13
. The clearance adjustment mechanism
22
adjusts the clearance in an oblique direction relative to the two sides of each of the lower cutting edge
13
and the upper cutting edge
12
which form the L shape.
A work-cutting device with the generally L-shaped upper cutting edge
12
and the lower cutting edge
13
is referred to as a “right-angle shearing machine” and is generally used for cutting the work W in its corner into a rectangular piece Wb. In such a work-cutting device, if the clearance adjustment mechanism
22
adjusts the clearance in the oblique direction as described above, the two sides of the upper cutting edge
12
which form an L shape can simultaneously be subjected to clearance adjustments, thereby preventing possible abrasion of the upper cutting edge associated with its elevation, using the simple construction.
According to the present invention, the clearance control means
35
may adjust the clearance depending on the thickness of the work W while the upper cutting edge
12
is lowered during work cutting, and may adjust the clearance, during the elevation of the upper cutting edge, to a value larger than that during lowering.
In addition to the present invention, the clearance adjustment mechanism
22
includes means
21
for moving the position of the upper cutting edge
12
in a horizontal direction and an adjustment drive source
25
for driving the means
21
.
REFERENCES:
patent: 3756110 (1973-09-01), Von Arx
patent: 3791248 (1974-02-01), Pearson
patent: 3942400 (1976-03-01), Roch
patent: 4739490 (1988-04-01), Hayashi et al.
patent: 5568754 (1996-10-01), Chun
patent: 5706711 (1998-01-01), Ito
patent: 5852964 (1998-12-01), Sahashi
patent: 5967014 (1999-10-01), Hayashi et al.
patent: 5970839 (1999-10-01), Sahashi
patent: 11-10437
Armstrong Westerman & Hattori, LLP
Ashley Boyer
Druan, Jr. Thomas J.
Murata Kikai Kabushiki Kaisha
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