JPH0671361A - Device for gripping work in transfer bar - Google Patents

Abstract

PURPOSE:To improve the accuracy of a transfer bar in a forging press by holding a work from both sides by a gripper. CONSTITUTION:Of the transfer bars clamping the work W from both sides, the limit that one bar 1B can advance inside is made shorter than the limit of the other bar 1A because a stopper 15 is added to the bar 1B. Simultaneously, in the other transfer bar 1A, the gripper 12A of the tip end is always pressed inward by means of a spring 16. One gripper 12B is stopped at a clamp reference position K, and only the other gripper 12A is further advanced to clamp the work. At the time of unclamping, the gripper 12B remains stopped and only the gripper 12A is retreated to release the work at the reference position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer bar mechanism in an automatic forging press, and more particularly to a technique for improving the positional deviation of a work held by a gripper.

[0002]

2. Description of the Related Art A forging press equipped with a transfer bar has a plurality of molds arranged side by side, each time a work is press-molded.
This device is suitable for sending to the next mold to undergo new molding and efficiently continuing a series of molding to obtain mass-produced products. It is a transfer bar that supplies the work to a plurality of molds. A pair of transfer bars bridging on the upper surface of the lower mold in the press and having a plurality of pairs of grippers attached to the tips as shown in FIG. The work is conveyed from one die to the next die by repeating the movements in the order of clamp C, advance A, down D, open O, and return R. In the clamp movement, a plurality of grippers are attached to the pair of transfer bars so as to approach each other, and the work is sandwiched and gripped from both sides at the completion point of the clamp. Since the shape and size of the work differ depending on each mold, and the shape and size of the gripper are changed accordingly, each gripper presses the work in the clamping direction in order to grip all the works at the same time. You have to hold it. This pressing action has conventionally been carried out entirely depending on the biasing force of the spring.

FIG. 4 shows an example of the prior art, in which a bearing 102 is fixed to an outer surface 101 (left side in the figure) of a horizontal beam 1a having a hollow rectangular cross section, and the inside of the bearing is clamped, and the direction of open movement is shown. The sliding shaft 103 that can slide to the inside is fitted, and the spring 10 is inserted between the tip of the shaft and the bearing 102.
Insert 4. Inner surface (right side in the figure) 105 of the beam 1a
The gripper attaching portion 106 is attached to the. The support plate 107 on the rear surface of the gripper mounting portion is always pressed in the clamping direction (rightward in the figure) by the tip of the sliding shaft that receives the biasing force of the spring 4a. Support plate 10
A rod 108 that penetrates the beam inner surface 105 and slides in the forward and backward direction of the clamp is fixed to the beam 7, and a gripper holder 19a is fixed to the tip of the rod. Although a gripper is fixed to the tip of this holder, it is omitted in this drawing. When the two beams move in the clamping direction, the work force can be securely grasped by the biasing force of the spring so as not to fall, and the next up movement can be performed. Several improved techniques have also been proposed. For example, the actual public 5
No. 6-45695 or a technique in which the operating range of the spring shown in FIGS. 5A and 5B is limited.

[0004]

FIGS. 6 (A) and 6 (B) show the basic operation common when the spring is used in the clamp mechanism. A pair of beams 1a and 1b on the left and right in FIG. A are closest to each other, and a spring 4a is compressed to a length F and grippers 12a mounted on the gripper holder 19a and a gripper 12b fixed to the beam 1b. And the disk-shaped work W is pressed and gripped between and. At this time, the center line of the work W is a line K1 coinciding with the center of the mold. In this state, the beams 1a and 1b move to sandwich and convey the work onto the next die. FIG. B shows a state in which the beam opens to the left and right on the next mold and the gripper releases the work. In order to release the work, the urging force that has been pressed up to that point must be relaxed, so the beams 1a, 1b must retract until the spring 4a extends to the length G and is relaxed.
That is, the common problem is that the work cannot be separated from the gripper unless the two beams retreat from the state of FIG. A, which is closest to each other, by a distance E, and the center line K2 of the work when it is separated falls by a distance E and falls. Cause The expansion / contraction length E of the spring must be minimized in order to minimize the deviation of the work center, but in the first step of the forging press work, the dimensional difference in the cutting length of the billet material and the peculiarities of the roll-formed product are Since a large dimensional difference is unavoidable, there was a limit to reducing the expansion / contraction length E.

FIGS. 5 (A) and 5 (B) show a prior art in which the displacement of the work is improved when the biasing force of the spring is applied to the engagement and disengagement of the gripper and the work. Beam 1 in the figure
c moves back and forth by the clamp stroke, and the gripper slide base 109 is fixed on the beam. A long hole 110 penetrates through the gripper slide in the clamp direction, and a bolt 111 that determines the position of the spring 4c is vertically inserted into the long hole. That is, the length X of this long hole 110
Corresponds to the maximum movable gap of the gripper 12c. In this technique, in order to further reduce the distance X of the conventional work and reduce the deviation of the disengagement position of the work W, a stopper 112 is attached to the rear end of the gripper 12c, and between the adjustment screw 114 and the stopper placed on the holder 113. This is the content in which the interval C is provided. By doing so, the distance C is adjusted within a range smaller than the conventional maximum clearance X so as to reduce the positional deviation of the work. However, as is apparent from this technique, it is impossible to make the deviation of the work separation position zero in the structure using the spring. When the dimensional accuracy of a formed product is required to a higher level as in recent years, basically, a change in idea is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work gripping device which has a relatively simple structure in order to solve the problems described above and which always maintains a constant position for releasing a work from a gripper.

[0007]

A transfer bar work gripping device according to the present invention includes a means for converting the rotation of an eccentric cam into a forward / backward movement of a transfer bar 1, and a transfer bar which is always pressed inward from both sides. The transfer limit of the transfer bar 1B is set so that the inward travel limit of one transfer bar 1B is different from that of the other transfer bar 1A, and only the gripper 12A at the tip of the other transfer bar 1A can always move forward and backward. The above problem has been solved by being urged by.

Further, specifically, the link mechanism 3 for converting the rotation of the eccentric cam 2 into forward and backward movements and the support 11 of the transfer bar 1 can be freely moved back and forth between the plunger 31 which is the tip of the link mechanism. It is preferable that the air cylinder 4 is urged toward the clamp direction to urge the transfer bar 1B toward the clamp side, and the traveling distance of one transfer bar 1B to the clamp side is limited to be smaller than that of the other transfer bar 1A. Specifically, the support 11B of the one transfer bar 1B slidably moves back and forth along a guide 13B penetrating the inside thereof, and a stopper 15 having an appropriate thickness is added to an inner fixing base 14B of the guide. On the other hand, the other transfer bar 1A has a spring 16 attached to the rear side and penetrates the transfer bar 1A to pass through the gripper 1 at the tip. It is very good practice another aspect biasing the A.

As another embodiment, two eccentric cams 2A and 2B having different eccentric amounts are horizontally arranged and axially supported,
The drive wheels 32A, 32B rolling on the circumference of the eccentric cam and the air cylinders 4A, 4B on both outsides urge the legs 17A, 17B of the transfer bar support body by compressing them.
The phase shift may be formed between the horizontal movements of the two supports 11A and 11B.

[0010]

The operation of the present invention will be described with reference to FIG. 1 showing an embodiment. The rotation of the eccentric cam 2 is converted into a horizontal movement of the plunger 31 at the tip thereof via the link mechanism 3. Two
Supports 11A, 1 for book transfer bars 1A, 1B
Both 1B are always pressed inward by the biasing source 4 from the outside, while they move forward and backward from the inside by the horizontal movement of the plunger. When the plunger moves inward due to the rotation of the eccentric cam, both supporting members also move inward due to the pressing force of the urging source, and the distance between the grippers 12A and 12B at the tip of the transfer bar approaches. However, at one point only one transfer bar 1B
Because it is blocked by the progress limit set shorter than the other,
Even if the plunger 31B moves inward, the gripper 12B at the tip stops moving at this position, and only the other transporter 1A continues to move regardless of this, and the gripper 12A at the tip reaches the work and further advances. The urging force attached to the rear part of the gripper is pushed back by the support 11A to be pushed, and the work sandwiched by both pressing forces is surely gripped.

The position of the tip of the gripper 12B, which is short and limited, is the clamp reference position K. After the clamped work W reaches the top of the next die, the unclamping action, that is, the gripper 12 opens horizontally to release the work, but the main point of the action is that this clamp reference position can be maintained. . Due to the rotation of the eccentric cam, both of the plunger tips of the link mechanism start horizontal movement from the closed state to the outward opening direction. However, at the time of the previous clamping action, one transfer bar 1B stops toward the center and at a position farther than the other, so that a gap is formed between the support body 11B and the plunger 31B. Even if the plunger 31B moves until the gap disappears, the gripper 12B does not move while staying at the fixed position, that is, the clamp reference position K, and only the other gripper 12A immediately responds to the movement of the plunger 31A and is attached to the rear side. Since the force is reduced to retreat and the force for gripping the work W is lost, the work is released at the reference position and accurately fits into the mold.

[0012]

FIG. 1 shows an embodiment in which one eccentric cam 2 is rotated to activate the clamping and opening of two transfer bars 1A and 1B. When the shaft 21 of the eccentric cam 2 is rotated by receiving a driving force (not shown), this movement is caused by the driving wheel 3
2. Through the drive lever 33 and the driven lever 34, the plungers 31A and 31B are converted into horizontal movement. Both the plungers are pressed from the outside by the tips thereof and the tips of the cylinder rods 41A, 41B of the two air cylinders 4A, 4B are interposed between the legs 17A, 17B of the supports 11A, 11B.
Since the eccentric cam rotates, the support also moves back and forth horizontally as the position of the drive lever changes due to the rotation of the eccentric cam. It is guides 18A and 18B that support the support body so that it can move back and forth at a fixed horizontal level.
Both guides slide through the support. Inner fixing bases 14A and 14B are provided inside both guides, and inner fixing bases 13A and 13B are provided outside. In addition, only one of the inner fixing bases 14B has a stopper 15 having a thickness T that limits the movement of the support.
Of the two support bodies that have moved inward at the same speed up to this point, one of the transfer bars 1B
However, only the other transfer bar 1A continues to move further, and the gripper 12A fixed to the tip of the gripper support 19A hits the work W. The one gripper 12B cannot be moved due to its position being restricted, and the other gripper 12A tries to further advance the distance S by the forward movement of the plunger and the pressing force of the air cylinder 4A, and compresses the spring 16 connected to the rear of the gripper 12A. Grips the work piece securely. The biasing source may be a hydraulic cylinder or a spring in addition to the air cylinder.

In the clamped state, a gap equal to the thickness T of the stopper 15 is formed between the inner side surface of the one plunger 31B and the leg portion 17B of the support body stopped in front of it. In this state, after a series of steps from the clamp step and one molding is completed, the unclamp step of fitting the work into the next die is started. Here, the plunger that has been closed by the rotation of the eccentric cam starts to open horizontally toward both sides, but it is the other transfer bar 1A that immediately responds to the operation of the plunger.
However, the transfer bar 1B on one side remains stopped at that position without the movement of the plunger 31B being transmitted until the clearance is eliminated. When the other plunger 31A moves by pushing back the urging force of the spring 16 and the work loses the gripping force and is accurately fitted into the mold, the plunger 31B with the gap filled is first attached to the leg portion 17B of the support. It hits and begins to push, and the transfer bar 1B also starts moving outward.

FIG. 2 shows another embodiment of the present invention.
Two eccentric cams 2 without using a link mechanism or stopper
The configuration is such that the eccentricity amounts of A and 2B and the timings thereof are shifted, and the same operation as in the previous embodiment is exhibited.

[0015]

As described above, according to the present invention, basically, the rotation of the eccentric cam is converted into the horizontal movement of the transfer bar, and the gripper at the tip holds the work from both sides to carry it as required. It is a composition. However, unlike the prior art, the position where the clamped work is released on the mold always maintains an accurate fixed point without error, so the molded product by forging press has the effect of ensuring much higher quality than before. . Moreover, the structure for obtaining this effect is simple, and it can be carried out immediately with a slight modification to the conventional apparatus, which is extremely advantageous from the economical point of view.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention.

FIG. 2 is a front view of another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a gripper movement direction and order of a transfer bar.

FIG. 4 is a cross-sectional plan view showing one of the conventional techniques.

FIG. 5 is a vertical sectional front view (A) and a plan view (B) showing another conventional technique.

FIG. 6 is a partial vertical cross-sectional side view showing an operation common to the related art by (A) and (B).

[Explanation of symbols]

 1 Transfer Bar 2 Eccentric Cam 3 Link Mechanism 4 Energizing Source (Air Cylinder) 11 Support 12 Gripper 14 Inner Fixation Base 15 Stopper 16 Spring 17 Leg 18 Guide 31 Plunger

Claims (4)

[Claims] 1. A work W mounted on an automatic forging press to operate two front and rear transfer bars 1A and 1B three-dimensionally.
In a work gripping device for a transfer bar that grips and lifts and conveys the transfer bar to the next process position, a means for converting the rotation of the eccentric cam into a forward / backward movement of the transfer bar 1 and an urging force that constantly presses the transfer bar inward from both sides. The source 4 is set so that the inward travel limit of one transfer bar 1B is different from that of the other transfer bar 1A, and only the gripper 12A at the tip of the other transfer bar 1A is always biased forward and backward from the rear. The work gripping device of the transfer bar, which is characterized by being used. 2. The link mechanism 3 according to claim 1, which converts the rotation of the eccentric cam 2 into forward and backward movements, and the support 11 of the transfer bar 1 between the plunger 31 which is the tip of the link mechanism. It consists of an air cylinder 4 that pushes back and forth freely and urges it toward the clamp direction. The traveling distance of one transfer bar 1B toward the clamp side is limited to be smaller than that of the other transfer bar 1A. Transfer bar work gripping device. 3. The support body 11B of one of the transfer bars 1B according to claim 1 or 2, is slidably moved back and forth along a guide 18B penetrating the inside thereof, and has a proper thickness to the inner fixing base 14B of the guide. While the stopper 15 is added, the other transfer bar 1A has a spring 16 attached to the rear so as to penetrate the transfer bar 1A and urge the gripper 12A at the front end to grip the work piece of the transfer bar. apparatus. 4. The drive wheels 32A, 32B and the air cylinders on both outer sides of claim 1, wherein two eccentric cams 2A, 2B having different eccentric amounts are horizontally arranged and axially supported, and roll on the circumference of the eccentric cam. The work of the transfer bar is characterized in that the legs 17A, 17B of the transfer bar support are clamped and urged by 4A, 4B to form a phase shift between the horizontal motions of both the supports 11A, 11B. Grasping device.