JPH11300421A - Press brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure safety by preventing body and obstacles from being in contact with an upper table during the upper table is lowered at high speed. SOLUTION: A shielding material 8 for safety which is vertically moved along the upper table 6 is arranged in front of the upper table 6 of a press brake 1 and a high-speed lowering region and low-speed lowering region are set in the lowering stroke of the upper table 6. By operation for starting press motion, first, the shielding material 8 for safety is lowered to a prescribed position, next, the upper table 6 is lowered at high speed in the high-speed lowering region and, after stopping the table at the boundary point with the low-speed lowering region, the shielding material 8 for safety is elevated. In this way, the safety is secured with the shielding material 8 for safety during the upper table 6 is lowered at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a press brake for bending a steel sheet into a desired shape.

[0002]

2. Description of the Related Art A press brake comprises a fixed lower table and an upper table which moves up and down. A lower mold called a die is fixed to the lower table, and an upper mold called a punch is fixed to the upper table. Are bent into a desired shape with a steel plate interposed therebetween. Then, when bending the steel sheet, place the steel sheet on the die, lower the upper table first at a high speed by the start operation of the press, stop the upper table when the punch approaches the steel sheet to a predetermined distance, and then Then, it is lowered at a low speed and a steel sheet is sandwiched between the punch and the die to perform the bending operation.

[0003] In the bending operation of the steel plate by the press brake, the upper table is lowered at a high speed during a process until the upper table approaches the steel plate on the lower table. Equipped with safety devices so that they do not approach or touch the table.

There is a photoelectric safety device. In this photoelectric safety device, a light-emitting device and a light-receiving device are arranged on both sides of a work side of a lower table, and a light beam radiated between the light emitting device and the light receiving device is transmitted to the body or the body. As soon as the obstacle is blocked, the lowering of the upper table is stopped.

[0005]

However, the above-mentioned conventional photoelectric safety device has a quick response and is excellent in its effect. However, if the work material is small, the work material may be supported by an operator during the work. In this case, the operator's hands and parts of the body will be mounted on the lower table, and the light beam will be blocked, making it impossible to perform the press work, but stopping the operation of the photoelectric safety device. Doing this work is dangerous and causes inconvenience. Therefore, simply installing this photoelectric safety device does not mean that sufficient consideration has been given to safety.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a press brake which can ensure safety by preventing a body or an obstacle from contacting an upper table while the upper table is descending at a high speed. I do.

[0007]

According to the present invention, in order to attain the above object, a lower table for supporting a lower mold and an upper table for supporting an upper mold are arranged to face each other, and the upper table is provided. In a press brake that bends a steel plate placed on a lower mold by raising and lowering it with an upper mold, a safety shielding material that can move up and down along the upper table is arranged in the work area in front of the press brake. On the other hand, a high-speed descending area and a low-speed descending area are set in the descending stroke of the upper table, and the safety shielding material is lowered to near the lower table prior to the descending of the upper table by a press start operation. Control means for lowering the high speed descent area and stopping at the boundary point with the low speed descent area, then raising the safety shielding material, and then performing the press work while lowering the upper table at a low speed. Yes It is characterized in that was.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a press brake according to the present invention, first, a safety shield is lowered along a hoistway of an upper table by starting operation of a press to shield the front surface of the hoistway. When the safety shielding material is lowered to a predetermined position, the upper table is lowered at a high speed, and is temporarily stopped at a boundary point between a predetermined high-speed lowering region and a low-speed lowering region. Then, the safety shielding material, which shields the front of the hoistway of the upper table, is raised to a state where press work can be performed, the prepared material is inserted between the upper mold and the lower mold, and the press operation starts again. By performing the operation, the upper table is lowered at a low speed, and the material is sandwiched between the upper mold and the lower mold to perform the bending operation of the material.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a press brake according to the present invention. The press brake 1 is provided with a lower table 3 so as to connect a pair of side plates 2 opposed to each other. A slide guide 4 is provided above each side plate 2, and an upper table 6 is provided on the slide guide 4 so as to be able to move up and down by a press cylinder 5. A linear scale 7 for detecting the position of the upper table 6 at the time of elevating and lowering is provided on the side of the slide guide 4.

Numeral 8 denotes a safety shielding member for covering the front surface of the upper table 6, which is a curtain 9 made of a flexible material hung on a support bar 10, and the support bar 10 is disposed above the side plate 2. Chain 12 wound around a sprocket 11
Is connected to one end. The other end of the chain 12 is a shielding material cylinder 13 attached to the back of the side plate 2.
Of the piston rod 14
The safety shielding material 8 is moved up and down along the hoistway of the upper table 6 by the expansion and contraction of. Proximity switches 15 and 16 for detecting the extended position and the retracted position of the piston rod 14 are provided in the shielding material cylinder 13.

Reference numeral 17 denotes a control device for controlling the operation of the press brake 1. The control device 17 includes an operation switch (not shown) for operating each device of the press brake 1, and a foot switch 18 for starting a press operation and the above-mentioned switch. A program for performing control described later, such as receiving an input signal from the linear scale 7 or the proximity switches 15 and 16 and outputting an operation signal to the press cylinder 5 and the shielding material cylinder 13 is installed.

A lower mold 19 called a die is fixed on the upper surface of the lower table 3.
An upper mold 20 called a punch is provided at the lower end of the
The upper mold 20 is moved up and down based on the programmed control to perform a bending operation.

Next, the press brake control device 17
A procedure for bending a steel sheet by a program installed in the computer will be described based on the flowchart of FIG. S1 in the figure
S15 show the steps of each procedure.

First, a high-speed descent region and a low-speed descent region in the up-and-down stroke of the upper table 6 are set based on the material to be bent and the shape to be bent (S1).

Then, the steel plate to be bent is placed on a table or the like and prepared nearby, and the foot switch 18 is depressed as an operation for starting the pressing operation (S2). Foot switch 1
When the step 8 is depressed, the control device 17 operates the shielding material cylinder 13 to extend the piston rod 14 and lower the safety shielding material 8 (S3).

Here, the proximity switch 15 disposed on the shielding material cylinder 13 detects the completion of the extension of the piston rod 14, and determines whether or not the safety shielding material 8 has been lowered to a predetermined position (S4). Stop if it descends to (S
5). Although not shown, when the safety shielding member 8 does not descend to the predetermined position due to contact with an obstacle or the like, an alarm or the like may be issued or the machine may be stopped.

Next, the control device 17 operates the press cylinder 5 to lower the upper table 6 at high speed (S
6). Here, it is determined from the position information of the upper table 6 read from the linear scale 7 whether or not the upper table 6 has reached a preset boundary point between the high-speed descending region and the low-speed descending region (S7). For example, the operation of the press cylinder 5 is stopped to stop the lowering of the upper table 6 (S
8).

When the upper table 6 stops, the shielding material cylinder 13 is operated again to contract the piston rod 14 and raise the safety shielding material 8 (S9). When the safety shielding member 8 rises and the fronts of the lower mold 19 and the upper mold 20 are opened, a prepared steel plate is inserted between the lower mold 19 and the upper mold 20 (S10). .

When the insertion of the steel plate is completed, the foot switch 18 is depressed again (S11). Thus, the press cylinder 5 is operated again, this time lowering the upper table 6 at low speed (S12), and bending the steel plate inserted between the molds (S13). When the bending of the steel plate is completed, the press cylinder 5 is operated again to raise the upper table 6 (S
14), a series of press work is completed (S15). If the press operation is to be continued, the operation returns to step S2 to repeat the same operation as described above.

In the present embodiment, as an example of the timing for inserting the steel plate, as shown in the flow chart of FIG. 4, the safety shield is inserted in step S10 after the safety shielding material is raised. Before starting the press work,
That is, it may be performed before the operation of the foot switch in step S2. In this case, after raising the safety shield in step S9, the insertion of the steel plate in step S10 and the re-operation of the foot switch in step S11 are omitted. And step S
Steps may be advanced to lower the upper table 6 at a low speed of twelve.

[0022]

As described above, according to the press brake according to the present invention, the safety shielding member which can be moved up and down along the upper table is disposed in the work area in front of the press brake, while the upper table is provided. Set the high speed descent area and the low speed descent area in the descent stroke, lower the safety shielding material near the lower table prior to the lowering of the upper table by starting the press, and then lower the upper table at a high speed at high speed After lowering the area and stopping at the boundary point with the low-speed descending area, the safety shielding material was raised, and thereafter, there was a control means capable of performing press working while lowering the upper table at a low speed. While the upper table is descending at a high speed, the front surface is shielded by the safety shielding material, so that the body and obstacles do not approach the upper table, and safety can be ensured.

[Brief description of the drawings]

FIG. 1 is a front view of a press brake according to the present invention.

FIG. 2 is a rear view of FIG.

FIG. 3 is a side view of FIG. 1;

FIG. 4 is a flowchart showing an operation procedure using a press brake according to the present invention.

[Description of sign]

DESCRIPTION OF SYMBOLS 1 ... Press brake 3 ... Lower table 4 ... Slide guide 5 ... Press cylinder 6 ... Upper table 7 ... Linear scale 8 ... Safety shield 9 ... Curtain 10 ... Support bar 11 ... Sprocket 12 ... Chain 13 ... Shield cylinder 14: Piston rod 15: Proximity switch 16: Proximity switch 17: Control device 19: Lower die 20: Upper die

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16P 3/12 F16P 3/12

Claims (1)

[Claims] A lower table for supporting a lower mold and an upper table for supporting an upper mold are opposed to each other, and the upper table is moved up and down to form a steel plate placed on the lower mold. In a press brake that bends at the same time, a safety shield that can move up and down along the upper table is arranged in the work area in front of the press brake, while a high-speed descent area and a low-speed descent area are provided during the descending stroke of the upper table. Before the lowering of the upper table by the start operation of the press, the safety shielding material is lowered to the vicinity of the lower table, and then the upper table is lowered at a high speed in the high-speed lowering region, and the boundary point with the low-speed lowering region is set. A press brake comprising a control means for performing a press working operation while raising the safety shielding material after stopping at step (1) and then lowering the upper table at a low speed.