JP2013184167A - Transfer device for press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage of a device by eliminating an overload at clamping of a workpiece when there are variations in dimensions of workpieces in a transfer device in a press.SOLUTION: A pair of feed bars 21 having fingers for griping a workpiece and releasing it are made to open and close by opening/closing mechanisms 23, 24, 25, 26, 29 which can be freely retreated in a direction in which the intervals are widened but which are restrained in a direction in which the intervals are narrowed and similarly energizing means such as elastic members which energize the intervals in a direction in which the intervals between the pair of these feed bars 21 are narrowed. Accordingly, when the opening/closing mechanisms perform closing motion after the fingers provided to the feed bars 21 grip the workpiece, only the opening/closing mechanisms 23, 24, 25, 26, 29 are operated forward, the workpiece is held by elastic force of the elastic members and reaction force due to griping of the workpiece does not act on the feed bars 21.

Description

  The present invention relates to a transfer device that supplies a workpiece (workpiece) to a press machine that performs press processing, moves the workpiece to a mold position for processing, and conveys the processed material to discharge after processing.

  Conventionally, in press working, workers have been supplying and taking out mold parts of a press machine while holding a work piece with a long-sleeved last-like tool. In view of the above, in recent years, it is a common practice to use a transfer device as a kind of manipulator instead of a human hand. One example will be described with reference to the drawings.

  FIG. 4 is a perspective view showing an example of a press machine provided with a transfer device. 1 is a press machine, 2 is a feed bar drive device which is a main part of the transfer device, and 21 is a pair of feed bars driven by this drive device. It is. The worker who performs the press work is usually located on the left side of the figure, and now the work is supplied from the side of the press machine and discharged from the opposite side as seen from the worker.

  The feed bar 21 moves by a predetermined stroke in the transport direction (X direction), retreats the same distance, rises and falls in the vertical direction (Z direction), and the width direction of the pair of two feed bars 21 (Y direction). Open and close.

  FIG. 5 is a plan view of the transfer device. Fingers 22 are attached to the pair of feed bars 21a and 21b inward. In this example, there are six pairs of fingers 22. Of the pair of feed bars 21a and 21b, in the drawing, the upper feed bar 21a holds the work (hereinafter referred to as clamp), and the lower feed bar 21b releases the work (hereinafter referred to as unclamp). ) Shows the state.

  On the other hand, in this example, six stop positions A to H are set on the press machine side. Of these, three locations D, E, and F are in the mold portion in the press. The moving stroke in the X direction is a distance that moves from the A to the C and from the B to the D, for example, to the next stop position.

  In the standby state, the feed bar 21 is lowered. When conveying, the interval between the feed bars 21 is increased, the workpiece is clamped and lifted, and moved by one stroke. After moving, the feed bar 21 is opened to unclamp the work and return to the original position in the X direction. This is one cycle. In other words, the workpiece is moved to 1 by a series of three-dimensional operations of clamping (Y direction), ascending (Z direction), moving (X direction), descending (Z direction), unclamping (Y direction), and returning (X direction). Stroke transferred. There is also a two-dimensional feed bar only in the X and Y directions that does not perform the lifting operation.

  In the case of this press machine, two types of patterns are assumed for conveyance, assuming that there are two types, one that processes in one stroke by a mold and one that processes in two strokes. In the case of a one-stroke die, a workpiece is transferred from a parts feeder (not shown) at the A position, waiting at the next C position, processed at the next E position, and discharged by a chute or the like at the G position. In the case of a two-stroke die, delivery is performed at the B position, the first machining is performed at the D position, the second machining is performed at the F position, and the discharge is performed at the H position.

  The problem here is the variation in workpiece dimensions. In order to perform clamping smoothly, the interval when the finger is moved inward is set in advance by teaching. However, if a workpiece having a size smaller than a predetermined size is introduced due to variations, clamping is not reliably performed. In addition, when a workpiece having a size larger than a predetermined size comes, the finger tends to be brought closer to the inside than the workpiece size, so that the opening / closing mechanism is forced, causing damage and deformation of the ball screw and each mounting portion. Particularly in an opening / closing mechanism using a servo motor that opens / closes a pair of feed bars at high speed, damage around the ball screw is fatal.

  In Patent Document 1, in a transfer feeder device of a forging press machine, a feed bar is used as a countermeasure against an overload acting on a support portion of the bar due to the feed bar vibrating up and down at a high speed for improving productivity. It describes that it is elastically supported in the vertical direction. Patent Document 2 describes an overload mitigation measure due to a torsional external force generated in a transfer feeder having driving devices on both sides of a press. However, none of them are measures against overload due to uneven size of workpieces.

JP 2007-283384 A JP 2006-346686 A

  SUMMARY OF THE INVENTION An object of the present invention is to realize a transfer device for a press machine that can prevent damage to a finger or a feed bar opening / closing mechanism due to an overload caused by unevenness of workpiece dimensions.

  The present invention described in claim 1 is a transfer device for supplying a workpiece from a side surface to a press machine and discharging the workpiece from the opposite side, and a pair of feed bars provided with fingers for grasping and separating the workpiece. It is characterized in that it is opened and closed by an opening / closing mechanism that restrains only in the closing direction while allowing the interval to freely retreat, and an urging means that urges the pair of feed bars in the direction of narrowing the gap. It is a transfer device of a press machine.

  The present invention according to claim 2 further includes a frame holding the feed bar and the opening / closing mechanism according to the invention of claim 1, wherein the biasing means is disposed between the frame and the feed bar. This is a transfer device for a press machine.

  Further, the present invention according to claim 3 is the transfer device of the press machine according to claim 1 or 2, wherein the opening / closing mechanism is configured to be driven by a servo motor.

  According to the present invention, the fingers grip the workpiece by moving the feed bar in the direction in which the interval is narrowed by the opening / closing mechanism. In this case, if the operation amount of the opening / closing mechanism that narrows the interval between the feed bars is excessive with respect to the outer dimensions of the workpiece, the feed bar resists the urging force by the urging means such as the elastic force of the elastic member. In contrast, the opening / closing mechanism is not subjected to an excessive reaction force by gripping the workpiece. Since the elastic force or urging force acts on the feed bar in the direction of narrowing the interval, the work can be grasped by the elastic force or urging force. Therefore, by setting the amount of movement of the opening and closing mechanism so that a smaller work can be gripped than a steady work, it is possible to avoid losing grip on a work smaller than the normal work, and to ensure a steady work or a larger work. In this case, since the feed bar moves backward with respect to the opening / closing mechanism as described above, it is possible to avoid applying an excessive load to the opening / closing mechanism. In other words, according to the present invention, it is possible to prevent a clamping error due to unevenness of dimensions, and in the transfer device using a high-speed servo motor, there are excellent effects of preventing damage to equipment around the feed bar. Particularly in an opening / closing mechanism using a servo motor that opens and closes a pair of feed bars at a high speed, the effect of avoiding damage around the ball screw is great.

It is a top view of the opening / closing mechanism of the feed bar in the Example of this invention. It is a side view of the opening / closing mechanism of the feed bar in the Example of this invention. It is a perspective view which shows a part of opening / closing mechanism of the feed bar in the Example of this invention. It is a perspective view of a forging press provided with a conventionally known transfer device. It is a top view of a conventionally well-known transfer apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view of an opening / closing mechanism for a pair of feed bars 21 in the feed bar driving device, and FIG. 2 is a side view. 1 and 2 both show the unclamped state on the right side and the clamped position on the left side from the center line. In the following description, the same reference numerals as those in FIG. 4 or FIG. May be omitted.

  Inside the rectangular frame 20, a screw shaft 26 is rotatably held with the central axis directed in the opening / closing direction (approaching / separating direction) of a feed bar 21, which will be described later. The rotary shaft has a right-handed screw and a left-handed screw, and a moving block 25 having a ball screw is engaged with each of the right and left screws. One end of the screw shaft 26 passes through the frame 20, and includes a pulley attached to the protruding end, a timing belt wound around the pulley, and a pulley around which the timing belt is wound. It is connected to an opening / closing drive unit 29 composed of an AC servomotor. That is, when the screw shaft 26 is rotated by an AC servo motor, the moving blocks 25 screwed to the screw shaft 26 are configured to approach or separate from each other by the action of the screw.

  A support plate 23 is placed on the moving block 25 via a lower hardware 24. The lower hardware 24 is not directly fixed to the moving block 25 by bolts or the like so as to be integrated with each other, and the movement is restricted (restricted) in the direction in which the moving blocks 25 approach each other (direction in which the interval is closed). On the contrary, the moving block 25 is locked to the moving block 25 so as to freely move backward in a direction away from each other (a direction in which the interval is opened). For example, the lower hardware 24 is locked to the moving block 25 by an L-shaped flange on the outside thereof. The support plate 23 and the lower hardware 24 are fixed with bolts so as to be integrated with each other. A perspective view of both is shown in FIG.

  A feed bar 21 is attached to the support plate 23, and fingers for gripping the workpiece are provided on the feed bar 21. These feed bars 21 and fingers may be conventionally known, such as the configuration described in the above-described patent document.

  The present invention includes an opening / closing mechanism that restrains a pair of feed bars 21 provided with fingers for gripping and releasing a workpiece only in a closing direction while allowing the pair of feed bars 21 to freely retreat in the opening direction, and an interval between the pair of feed bars. It is characterized in that it is opened and closed by a biasing means for biasing in the direction of narrowing. That is, in the above-described configuration, by rotating the AC servo motor, the screw shaft 26 connected thereto rotates, and the support plate 23 and the feed bar 21 attached thereto approach each other according to the rotation direction. Or move away. When the feed bars 21 are moved in a direction approaching each other in order to grip the workpiece by the fingers, the workpieces disposed between the fingers are gripped by the fingers. This operation is performed when the screw block 26 rotates in a predetermined direction and the moving blocks 25 screwed to the screw shaft 26 move in directions approaching each other. Since the lower metal piece 24 receiving the elastic force of the compression spring 27 as an urging means is pressed against the moving block 25 (the movement in the closing direction is restricted), the moving block 25 moves forward. Following this, the lower hardware 24 and the feed bar 21 integrated with the lower hardware 24 via the support plate 23 move in a direction approaching each other.

  Thus, the feed bar 21 and the finger attached thereto are closed, and the work is gripped by the finger. When the screw block 26 further rotates from that state and the moving block 25 moves forward, the support plate 23 engaged with the moving block 25 via the lower hardware 24 and the feed bar 21 integrated therewith grip the workpiece. However, since the moving block 25 cannot move forward any more, the moving block 25 moves backward relatively, so that only the moving block 25 moves forward. In this state, the support plate 23, the feed bar 21 integrated with the support plate 23 and the finger are pushed in a direction approaching each other due to the elastic force of the compression spring 27, so that the finger holds the workpiece. Therefore, the reaction force caused by gripping the workpiece does not particularly act on the screw shaft 26 or the moving block 25 screwed to the screw shaft 26.

  When this is viewed from the side of the moving block 25, when the pair of moving blocks 25 move outward, the support plate 23 to which the feed bar 21 is attached follows the movement block 25, but the moving block 25 moves inward. If you move towards you, you will not follow and will be left behind. However, as shown in FIG. 1, the support plate 23 is always biased inward by a biasing means, for example, a compression spring 27, with respect to the frame 20. That is, the compression spring 27 is disposed between the support plate 23 and the frame 20, and the support plate 23 is pushed by the compression spring 27 in a direction away from the frame 20 (a direction in which the support plates 23 approach each other). Therefore, as long as the support plate 23 can move, the support plate 23 moves inward (in a direction in which the support plate 23 approaches each other) to follow the moving block 25. In other words, when it is forcibly opened by an external force, or when the moving block 25 continues to move inward with a workpiece having a large size interposed therebetween, only the support plate 23 opens or stays in that position. Is possible. In the figure, reference numeral 28 denotes a linear guide provided on both sides in order for the support plate 23 to move smoothly in parallel.

  As shown in FIG. 1, if the compression spring 27 is provided separately from the screw shaft 26, maintenance of both is easier, and a larger size spring can be used inside the limited frame 20. It is preferable because a sufficient elastic force can be exhibited regardless of the opening / closing position.

  In addition to the elastic member such as a compression spring, an air spring, an air cylinder, or the like can be used as the biasing means.

  The transfer device according to the present invention has the following two effects. First, when a workpiece having a size larger than the set value is supplied, the feed bar 21 stops moving in the closing direction in accordance with the size, so that no load is applied to any part of the opening / closing mechanism. No damage will occur. As described above, in a transfer device that uses a high-speed servo motor called a servo transfer device, the screw shaft 26 of the opening / closing mechanism repeats high-speed forward rotation and reverse rotation, so that prevention of damage to the opening / closing mechanism also leads to improvement in productivity. It is an important matter.

  Secondly, when teaching is performed before operation, teaching can be easily performed because the finger can be manually opened and aligned without operating the opening / closing mechanism and adjusting the dimensions.

  In addition, since the transfer apparatus of the present invention can easily cope with a larger dimension, assuming that a workpiece smaller than the set dimension is supplied, the prior setting is performed with a smaller size than the conventional one. It is good to do so.

  DESCRIPTION OF SYMBOLS 20 ... Frame, 21 ... Feed bar, 23 ... Support plate, 24 ... Lower metal part, 25 ... Moving block, 26 ... Screw shaft, 27 ... Compression spring, 29 ... Opening / closing drive part

Claims (3)

In the transfer device that feeds the workpiece from the side to the press and discharges it from the opposite side,
An opening / closing mechanism that restrains the pair of feed bars provided with fingers for gripping and releasing the workpiece only in the closing direction while allowing the pair of feed bars to freely retreat in the opening direction, and the direction of narrowing the distance between the pair of feed bars. A pressing machine transfer device characterized in that it is opened and closed by an urging means for urging to the press. A frame holding the feed bar and the opening / closing mechanism;
The transfer device of a press machine according to claim 1, wherein the biasing means is disposed between the frame and the feed bar.   2. The transfer device for a press machine according to claim 1, wherein the opening / closing mechanism is configured to be driven by a servo motor.

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