JPS6347375Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a mold device for a press brake, and more particularly to a mold device for bending the vicinity of one end edge of a plate-shaped workpiece into a circular arc shape with a small radius.

Conventionally, there is a type of mold device that uses a rubber die in the lower mold to bend the edge of a plate-shaped workpiece into a small-diameter arc shape. Considering deterioration, etc., it was not completely satisfactory.

Conventionally, a bending die with a bell-crank or V-shaped cross section is swingably provided to bend the workpiece along the cross-sectional shape of the upper die. be. For example, Utility Model Publication No. 51-35975 (hereinafter simply referred to as precedent example)
It is as shown in In this prior example, both sides of the workpiece are bent at the same time, and it is not suitable for bending only one side of the workpiece into an arc shape.

In other words, there is no mold that can satisfactorily bend only one side of a workpiece into an arc shape (U-shape).

This idea was made in view of the conventional problems mentioned above, and its purpose was to take spring back and tool life into consideration, and to form one side of the workpiece into an arcuate shape (U-shape) with a simple structure. The object of the present invention is to provide a mold device that can be easily bent.

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

The press brake 1 shown in FIG. 1 is of a type in which an upper apron 5 is provided at the upper part of left and right side walls 3, 3, and a lower apron 9 is moved up and down by being driven by a fluid pressure cylinder 7. .

An upper mold 11 is attached to the lower part of the upper apron 5, and a lower mold 13 is attached to the upper surface of the lower apron 9.
The upper mold 11 and the lower mold 1 are separated by raising and lowering the lower apron 9.
A plate-shaped workpiece W (Fig. 2,
4 and 5)).

As shown in FIGS. 2 and 3, the upper mold 11
is provided with a round bar-shaped portion 15 having a cross-sectional shape and a desired radius of curvature R at its tip, and is formed slightly above the tip to be thinner than 2R and inclined, for example, about 10 degrees from the vertical direction.

The lower mold 13 has three parts: a front block 17, a rear block 19, and a bottom block 21 extending in the left-right direction (in the front and back directions of the paper in FIGS. 2, 4, and 5).
The blocks are appropriately assembled and provided, and bearing blocks 23 are attached to both longitudinal ends (both left and right sides) of the lower mold 13.

The bearing blocks 23, 23 have shafts 25 at both ends.
A swinging bending die 27 supported by a bell crank and having a bellcrank cross section is swingably provided.

An inclined surface 29 is machined on the inner upper part of the rear block 19 so as to form a space that allows the swinging bending die 27 to swing. Further, a plurality of spring seat holes 31 are machined on the upper surface of the joint bottom block 21.

A bomb 33 is compressed and inserted into the spring seat hole 31, and urges the upwardly projecting upper leg 35 of the swing bending die 27 to swing toward the inclined surface 29.

In the final stage of bending of the swing bending mold 27 shown in FIG. There is.

At the end of the first engagement surface 37 on the side of the upper mold 11, a second
The second engagement surface 39 tilted downward to the left in the figure,
Further, a third engaging surface 41 is provided as a protruding portion following the second engaging surface 39 and protruding toward the upper mold 11 side.

As described above, the swinging bending mold 27 has a bellcrank-shaped cross section, and includes an upper leg 35 that projects upward and a lower leg 43 that projects forward.
The upper surface in FIG. 2 is the fourth engagement surface 45.

In the above configuration, when the workpiece W is in the state shown in FIG.
is positioned above the lower mold 13.

At this point, the swinging bending mold 27 swings clockwise around the shaft 25 shown in FIGS. 1, 4, and 5 due to the urging force of the bomb 33, as shown in FIG. The rear upper end of the swing bending mold 27 is in contact with the inclined surface 29, and the front end of the first engaging surface is located slightly higher than the level of the upper end surfaces of the front block 17 and rear block 19 of the lower mold 13. .

The initial lower pressure is when the upper die 11 and the lower die 13 are brought close together and the lower end of the upper die 11 comes into contact with the workpiece W and starts downward pressure.At this point, the first engagement of the swing bending die 27 Since the front end of the surface 37 is pressed down, the swinging bending die 27 is slightly swung counterclockwise around the shaft 25.

Therefore, the lower surface of the lower leg 43 of the swing bending die 27 swings against the biasing force of the bomb 33, and the lower leg 4
3 comes into close contact with the upper surface of the joint bottom block 21.

Further, when the upper die 11 presses down the workpiece W and descends, the lower surface of the workpiece W is moved to the second position as shown in FIG.
It comes into contact with the engagement surface 39 (second stage lower pressure), swings the swinging bending die 27 clockwise around the shaft 25, and the rear surface of the upper leg 35 of the swinging bending die 27 tilts again. This results in contact with surface 29.

As the downward pressure of the upper die 11 further progresses, the upper die 11 applies downward pressure on the upper surface (fourth engagement surface 45) of the lower leg 43 of the swing bending die 27 via the workpiece W (the state shown in FIG. 5),
At the final lower pressure, the lower surface of the lower leg 43 comes into contact with the upper surface of the joint sole block 21 as shown in FIG.

During this process, the third engaging surface 41 approaches from the side the thinner part above the round rod-shaped part 15 at the lower end of the upper mold 11, overbending the workpiece W to about 190 degrees as described above. Yes (see Figure 2).

In the step of separating the upper die 11 and the lower die 13, the swing bending die 27 is moved by the urging force of the bullet 33 and the action of the workpiece W pressing the third engagement surface 41 backward. Because the clockwise rocking of the
The rear surface of the upper leg 35 of the swing bending mold 27 abuts against the slope 29.

Therefore, there is no problem in removing the folded product upwardly together with the upper die 11.

In summary, the present invention has a swing bending die with a simple structure, bends the workpiece into an arc shape along the tip of the upper die, performs overbending to compensate for the springback, and bends the workpiece into an arc shape. Only the side portions can be easily bent into an arc shape and pressurized, eliminating the disadvantages of conventional devices.

It is also clear that the design can be easily changed without departing from the technical idea of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a front view of the press brake, Fig. 2 is a vertical sectional view of the embodiment of the device of the present invention, Fig. 3 is a right side view of Fig. 2, and Fig. 4 is the rocking during the second stage pressurization. FIG. 5 is a diagram illustrating the state of the oscillating bending mold, etc. at the time when the final downward pressure is started. Explanation of symbols representing main parts of the drawings, 1...Press brake, 11...Upper die, 13...Lower die, 27
……oscillating bending mold, 29… inclined surface, 37… first
Engagement surface, 39... second engagement surface, 41... third engagement surface, 45... fourth engagement surface.

Claims (1)

[Scope of utility model registration request] A mold device comprising a lower mold 13 that performs arc bending at the end of a workpiece W in cooperation with an upper mold 11 attached to an upper apron 5 of the press brake 1,
In the lower mold 13, between the front block 17 and the rear block 19, which are spaced apart from each other in the front and rear, a swing bending mold 27 having a bellcrank cross-sectional shape is disposed on the left and right bearing blocks 23 via a shaft 25. In this swing bending mold 27, a space is provided between the back surface of the upper leg 35 that projects upward and the rear block 19 to allow swinging, and a space that allows the upper leg 35 to swing forward is provided at the upper front surface thereof. The upper mold 11 is provided so as to be able to freely come into contact with the upper surface of the lower leg 43 protruding forward in the swing bending mold 27, and the swing bending mold 27
A mold device for a press brake, characterized in that the back surface of the upper leg 35 is biased in a direction in which it comes into contact with the rear block 19.