JPS63162B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shearing machine, and more particularly to a mechanical shearing machine in which a ram is moved up and down by rotation of an eccentric shaft (crankshaft).

As is well known, some types of shearing machines have a type in which a ram is moved up and down by the operation of a hydraulic cylinder, and a type in which a crankshaft (eccentric shaft) and a ram are connected via a connecting rod to move the ram up and down by the operation of a hydraulic cylinder. There is a type in which the ram is moved up and down by rotating a shaft, and the latter type is generally called a mechanical shearing machine.

In the mechanical shearing machine described above, a minute gap exists between the connecting portion between the eccentric shaft and the connecting rod and the connecting portion between the connecting rod and the ram. Therefore, when the ram is lowered to shear the workpiece, the gap on the lower side of both the connecting parts becomes zero due to the shearing resistance, and the gap shifts toward the upper side. At the end of shearing, the shearing resistance is instantaneously released, so the part that had been elastically deformed due to the shearing resistance instantly returns to its original state, and the ram etc. falls only in the gap. It is something. Therefore, a large impact is generated in the gap, resulting in severe noise and wear.

The present invention was made in view of the above-mentioned problems in the prior art, and its purpose is to absorb the looseness of the minute gap that exists in the connection between the connecting rod, the eccentric shaft, and the ram, thereby reducing noise and wear. The present invention aims to provide a shearing machine that suppresses such problems.

Hereinafter, a preferred embodiment of the present invention will be described based on the accompanying drawings.

In the accompanying drawings, reference numeral 1 denotes a shearing machine main body according to the present invention, and a lower blade 7 is attached to a table 5 provided on a frame 3 of the shearing machine main body 1.
An upper blade 11 is provided on the top via a ram 9.

The upper end of the ram 9 is connected to a connecting portion 15 provided at the distal end of a connecting rod 13, and the proximal end of the connecting rod 13 is
It is connected to an eccentric drive shaft 17 that is connected to a drive device (not shown).

Therefore, when the eccentric drive shaft 17 is rotationally driven, the upper blade 11 is connected via the connecting rod 13.
A ram 9 equipped with a ram 9 moves up and down toward the lower blade 7.

A workpiece W is mounted on the frame 3 above the ram 9.
A counterbalance cylinder 19 is installed to prevent impact applied to the connecting portion 15 of the ram 9 after shearing and wear caused by the impact, and the piston rod 2 of this counterbalance cylinder 19
1 is connected to the ram 9.

A hydraulic control circuit 25 is connected to the working pressure chamber 23 within the counterbalance cylinder 19 .

As shown in the drawing, this hydraulic control circuit 25 connects a first branch passage 31 and a second branch passage 33 through a check valve 29a in the middle of a fluid pressure passage 29 that connects the working pressure chamber 23 and the working pressure tank 27. The first branch passage 31 is provided with an accumulator 37 via a slot and check valve 35. Further, a plurality of fluid cylinders 43 are connected to the accumulator 37 via solenoid valves 39 to operate plate holders 41, which are referred to as plate holders.

Further, a tank port 47 is provided in the second branch passage 33 via a relief valve 45 .

The accumulator 37 includes a pressure accumulator 49 for accumulating working pressure fluid, and an accumulator piston 53 that protrudes and retracts into the pressure accumulator 49 via an elastic member 51 such as a splinter. An oil passage 55 that connects the first branch passage 31 and the solenoid valve 39 is provided within the solenoid valve 49 .

Next, the operation of this embodiment constructed as described above will be explained.

First, before shearing the workpiece W, the ram 9 is at the upper limit position as shown in the figure, the counterbalance cylinder 19 is contracted, and the working pressure chamber 23
The ram 9 is raised and lowered once from the state in which the working pressure fluid is flowing into the accumulator 37, thereby accumulating the working pressure fluid in the accumulator 37.

That is, when a drive device (not shown) is operated to rotate the eccentric drive shaft 17 and lower the ram 9 via the connecting rod 13, the piston rod 21 of the counterbalance cylinder 19 is pulled downward. The working pressure fluid that has been supplied into the working pressure chamber 23 flows out into the fluid pressure passage 29 via the piston 19a.

The working pressure fluid that has flowed out into the fluid pressure passage 29 is
The pressure is accumulated in the pressure accumulation chamber 49 through the check valve 35a of the branch passage 31, but since the amount of oil Q _C generated by lowering the ram 9 is larger than the amount of oil stored in the pressure accumulation chamber 49 Q _A. In other words, since the relationship Q _C >Q _A holds, the excess oil amount Q _H that cannot be accommodated in the pressure accumulation chamber 49 is discharged to the tank port 47 through the relief valve 45 of the second branch passage 33 .

When the ram 9 enters the upward stroke with the working pressure fluid accumulated in the accumulator 37 in this way, the pressure inside the working pressure chamber 23 of the counterbalance cylinder 19 becomes negative, so that the working pressure fluid is discharged from the working pressure tank 27. Actuating pressure fluid is sucked up through the fluid pressure passage 29 .

In this manner, when the ram 9 reaches its upper limit, the drive is temporarily stopped and shearing of the workpiece W such as a plate is started.

First, the workpiece W is inserted onto the lower blade 7 on the table 5, and the eccentric drive shaft 17 is rotated as described above.
The upper blade 11 is lowered together with the ram 9 via the connecting rod 13.

Immediately before the lowering operation of the ram 9 starts, the solenoid valve 39 is switched, and the second switching valve 39b is connected to the oil passage 55 and the fluid cylinder 43. As a result, the working pressure fluid accumulated in the pressure accumulating chamber 49 of the accumulator 37 passes through the oil passage 55,
It is introduced into the pressure chamber 43a of each fluid pressure cylinder 43, and the plate presser 41 is lowered.

On the other hand, the solenoid valve 39 switches,
When the working pressure fluid in the pressure accumulation chamber 49 flows out, the pressure in the pressure accumulation chamber 49 decreases, and the accumulation piston 53 is pushed out to the left in the figure by the elastic force of the elastic member 51. However, as the ram 9 descends, the working pressure fluid is discharged from the counterbalance cylinder 19 and flows into the pressure accumulating chamber 49 of the accumulator 37, so that the accumulator piston 5
3 moves rightward again against the elastic force of the elastic member 51, and the pressure of the working pressure fluid is accumulated in the pressure accumulation chamber 49.

In this way, first, the workpiece W is
is pressed down on the table 5, and then the ram 9 descends and the upper blade 11 and the lower blade 7 shear a predetermined position of the workpiece W.

Next, after the shearing process of the workpiece W is completed, the solenoid valve 39 is switched to the first switching valve 39 at the same time as the ram 9 is raised.
A is switched to block the oil passage 55.

In addition, during the upward stroke of the ram 9, the pressure inside the working pressure chamber 23 of the counterbalance cylinder 19 becomes negative, so working pressure fluid is sucked up from the working pressure tank 27 via the check valve 29a of the fluid pressure passage 29. .

At this time, a flow control valve 35b is provided in the first branch passage 31 so that a large amount of the working pressure fluid from the accumulator 37 does not flow into the working pressure chamber 23 of the counterbalance cylinder 19. The amount of throttling is determined by the flow from the accumulator 37 to the counterbalance cylinder 1 during the upward movement of the ram 9 and at the upper limit position of the ram 9.
This is to adjust the strength of pressure on 9.

By sequentially repeating the above-described operations, the shearing work can be carried out efficiently.

As can be understood from the above description of the embodiments, the gist of the present invention is as set forth in the claims.As is clear from the description, in the present invention, the frame is provided with The distal end of the connecting rod, whose proximal end is connected to the supported eccentric drive shaft, is connected to a ram that can move up and down, and the ram is connected to a counterbalance cylinder attached to the frame. .
Then, in order to shift the gaps upward at the joint between the eccentric drive shaft and the connecting rod and the joint between the connecting rod and the ram, pressure is applied to the working pressure chamber of the counterbalance cylinder to move the ram. is always biased upward.

Therefore, according to the present invention, even when the shearing resistance is released at the moment when the shearing of the workpiece is completed, the ram will not fall by the amount of the gap, and the impact will be alleviated accordingly. This makes it possible to suppress noise and wear.

Note that the present invention is not limited to the above-described embodiments, but can be implemented in other embodiments by making appropriate design changes.

[Brief explanation of the drawing]

The drawings are explanatory diagrams showing embodiments of the invention. Explanation of main symbols appearing in the drawings, 11...
Upper blade, 9... Ram, 13... Connecting rod, 7... Lower blade, W... Work, 19... Counter balance cylinder, 21... Piston rod, 23... Working pressure chamber, 27... Operation pressure tank,
29...Fluid pressure passage, 37...Accumulator, 41...Plate holder.

Claims (1)

[Claims] 1 A ram 9 equipped with an upper blade 11 that shears the workpiece W in cooperation with a lower blade 7 attached to the frame 3
is supported on the frame 3 so as to be movable up and down, and the distal end side of the connecting rod 13 is connected to the ram 9 at its proximal end side to the eccentric drive shaft 17 rotatably supported on the frame 3. The counterbalance cylinder 19 attached to the frame 3 is connected to the ram 9, and the gap between the connecting rod 13 and the eccentric drive shaft 17 and the connecting rod 13 are connected to each other. A shearing machine characterized in that the ram 9 is constantly urged upward by applying pressure to the working pressure chamber 23 of the counterbalance cylinder 19 in order to bias the gap between the connecting portion between the ram 9 and the ram 9 upward. .