JP2007076806A - Workpiece slipping-down prevention device in clamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To respond to slipping-down of a workpiece instantaneously when the workpiece inserted into a slot of a clamp, lifted, and transported slips down by fixed amount. <P>SOLUTION: This workpiece slipping-down prevention device is provided with a cam guide 33 having a tip part 33a plunging into the slot S, a spring 38 being an energizing means for moving and energizing the cam guide in the direction for letting the tip part of the cam guide plunge into the slot, and an eccentric cam 32 rotating in the interlocking relationship with travel of the cam guide. Although the tip part of the cam guide is abutted on a side face of the workpiece when the workpiece W is set to a predetermined position in the slot, the cam guide moves further into the direction for plunging into the slot by energizing force of the energizing means when the workpiece slips down and its upper end comes to a position lower than the tip part of the cam guide, and the eccentric cam is rotated and its engaging teeth bite into the side face of the workpiece to prevent further slipping-down of the workpiece. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a clamp, and more particularly to a workpiece slip prevention device that can effectively prevent a workpiece from slipping in the clamp.

In the following Patent Document 1, in a clamp having a structure in which a presser foot is brought into pressure contact with both side surfaces of a workpiece inserted into a slot and lifted and transported, a guide plate that always abuts on the upper end surface of the workpiece with a spring force; An eccentric cam that rotates in conjunction with the downward movement of the guide plate is provided. When the workpiece slides down from a predetermined position in the slot for some reason during lifting and transporting the workpiece, the eccentric cam rotates due to the accompanying downward movement of the guide plate, and the engaging teeth enter the slot. Engage with one side to prevent further sliding.
Japanese Utility Model Publication No. 61-36540

  According to the workpiece slip prevention device described in the above-mentioned patent document, when the workpiece slides down, the guide plate also moves downward at substantially the same speed by substantially the same distance, and at an angle and speed according to this downward movement amount. The eccentric cam rotates. The engaging teeth of the eccentric cam are located away from the side surface of the work when the work is inserted into a predetermined position in the slot (up to the depth of the slot). Even if the eccentric cam rotates slightly, the engaging teeth do not reach the workpiece side surface. That is, if the workpiece slip does not reach a certain amount or more, the sliding-off preventing action due to the engaging teeth of the eccentric cam biting into the side surface of the workpiece cannot be exhibited. Further, since the rotational speed of the eccentric cam is relatively slow, there is a case where the engagement tooth biting force with respect to the side surface of the workpiece cannot be sufficiently obtained. Accordingly, there has been a demand for the development of a work slippage prevention device that can respond instantaneously when the work slippage reaches a certain amount and can exert a slippage prevention action with a sufficient biting force.

  Moreover, in the workpiece sliding prevention device described in the above-mentioned patent document, a spring is used to move and urge the guide plate in a direction in which the guide plate is always in contact with the upper end surface of the workpiece. The spring force of the spring is transmitted through the guide plate. The work is always in the direction of dropping the work, and although the spring force of the spring is relatively small relative to the weight of the work, it has some mechanical problems.

  Therefore, the present invention solves the above-mentioned problem, and when the work being lifted and transported inserted into the slot of the clamp is dropped by a certain amount, it can instantly respond and exert a sufficient slip-preventing action, An object of the present invention is to provide a novel workpiece slip-off prevention device that is mechanically safe.

  In order to achieve this object, the present invention according to claim 1 is capable of entering a slot in a clamp of a type in which a workpiece is set at a predetermined position in a slot and lifted by pressing a pressure contact member on both side surfaces thereof. A cam guide having a tip, biasing means for moving and biasing the cam guide in a direction in which the tip of the cam guide enters the slot, and an eccentric cam that rotates in conjunction with the movement of the cam guide. Is set at a predetermined position in the slot, the tip of the cam guide is in contact with the side surface of the workpiece. At this time, the eccentric cam is substantially buried in the clamp body, and its engaging teeth are on the side surface of the workpiece. The cam guide receives the urging force of the urging means when the work slides down and the upper end of the work is positioned below the tip of the cam guide. In the clamp, characterized in that it is configured to move in the direction of entering the slot, thereby rotating the eccentric cam and causing its engaging teeth to bite into the side surface of the workpiece, thereby preventing further sliding of the workpiece. It is a work slipping prevention device.

  According to a second aspect of the present invention, in the workpiece slip prevention device according to the first aspect, the eccentric cam is rotatable about a shaft fixed to the clamp body, and one end of the eccentric cam rotates with the other end of the cam guide. When the cam guide is moved into the slot, the engaging teeth are rotated in a direction to enter the slot when the cam guide is moved into the slot.

  According to a third aspect of the present invention, in the work slippage preventing device according to the first or second aspect, the operation position in which the cam guide is urged to move in a direction to enter the slot by the urging means, and the direction And switching means for switching between the standby position biased to move in the opposite direction.

  According to the workpiece sliding prevention device of the present invention, when the workpiece is inserted into the slot of the clamp and the workpiece slides a certain amount during lifting and transporting, the cam guide and the eccentric cam are instantaneously moved by the biasing force of the biasing means. In response, the engaging teeth of the eccentric cam bite into the side surface of the workpiece, so that further sliding of the workpiece can be reliably prevented.

  FIG. 1 shows an intact clamp incorporating a work slippage preventing device as one embodiment of the present invention. A clamp body 10 having a pair of side plates 11, 11 (a side plate on the front side of the paper is not shown) arranged oppositely and spaced apart from each other has a leg portion with a slot S opened downward at the lower end thereof. 12 and 13 are provided.

  On the leg 12 side, a guide plate 14 that is inclined at a predetermined angle with respect to the vertical, and a wedge that can mesh with the rack teeth 14a of the guide plate 14 and move along the inclination direction of the guide plate 14 A body 15 is provided. A coil spring 17 is wound around the shaft of the bolt 16 penetrating the guide plate 14, thereby lifting the wedge body 15 from the guide plate 14 in the standby state (no load state) shown in FIG. 1. Support in the state. That is, at this time, the rack teeth 14a of the guide plate 14 and the rack teeth 15a of the wedge body 15 are not engaged with each other. The side surface 15b facing the slot S of the wedge body 15 is a vertical surface.

  Above the leg portion 12, a wedge body pushing crank cam 18 is pivotally supported by a shaft 19 fixed to the clamp body 10. The crank cam 18 can take two positions facing each other at a rotation angle of about 180 degrees between the standby position shown in FIG. 1 and the operation position (FIGS. 2 and 3) when lifting the workpiece. The former standby position is taken when the pin 21 is fitted, and the latter operating position is taken when the stopper pin 21 is fitted into the recess 18b. One end of a wedge body pushing handle 20 is fixed to the crank cam 18, and the other end 20a of the handle 20 protruding outside the clamp body 10 is gripped to move the handle 20 counterclockwise from the standby position in FIG. In the drawing, the crank cam 18 can be moved to the operating position by rotating the same in the rotational direction and the same in the vertical and horizontal directions.

  The rod 22 around which the compression coil spring 39 for pushing the wedge body is wound has one end 22 a fixed to the crank cam 18 and the other end 22 b fixed to the wedge body 15. When the crank cam 18 is in the standby position shown in FIG. 1, the shaft 19 is positioned slightly to the left of the rod 22, so that the coil spring 39 attaches the crank cam 18 to rotate around the shaft 19 in the clockwise direction. However, since the stopper pin 21 is fitted in the recess 18a, the standby position is maintained.

  An L link 25 is pivotally supported on a shaft 26 fixed to the clamp body 10 so as to be rotatable above the leg portion 13. The L link 25 is further rotatably connected to the lower end of the suspension ring 28 by a shaft 27 and is connected to the upper end of the holding link 30 by a shaft 29 so as to be rotatable. The lower end of the holding link 30 is pivotally supported on a shaft 31 fixed to the clamp body 10. Thus, when the suspension ring 28 is pulled upward, the L link 25 rotates around the shaft 26 in the counterclockwise direction, whereby the presser link 30 rotates slightly around the shaft 31 in the clockwise direction. The presser foot 24 connected to the vicinity of the lower end of the link 30 so as to be relatively rotatable moves in the right direction, and the side surface 24 a protrudes into the slot S.

  The leg portion 13 is further provided with a stopper cam 32, a substantially L-shaped safety cam guide 33 and a lock handle 34. The stopper cam 32 is rotatably supported on the shaft 31 together with the holding link 30 and includes engagement teeth 32a for frictionally engaging the side surface of the work inserted in the slot S. The base end of the lock handle 34 is pivotally supported by a shaft 35 fixed to the clamp body 10, and is pivotally connected to a substantially middle point of the cam guide 33 via a shaft 36 at the tip thereof. ing. The lower end of the cam guide 33 is connected to one end of the stopper cam 32 and a shaft 37 so as to be rotatable with each other.

  Further, a tension spring 38 is bridged between the left end position of the clamp body 10 and a position close to the shaft 37 of the cam guide 33. 1, the connecting shaft 36 between the cam guide 33 and the lock handle 34 is positioned on the left side of the straight line connecting the shaft 35 and the shaft 37. Therefore, the stopper cam 32 and the cam guide 33 are shown in the drawing. The engaging teeth 32a of the stopper cam 32 and the distal end portion 33a of the cam guide 33 are buried in the leg portion 13 without protruding toward the slot S.

  1 is set (the upper end of the work W is inserted deeply into the slot S), and then the handle 20 is moved counterclockwise against the spring force of the spring 39. When the rotation operation is performed, the crank cam 20 fixed integrally with the handle 20 also gradually rotates in the same direction around the shaft 19. Then, at the moment when the link 22 exceeds the shaft 19, the crank cam 18 is rotated at a stroke by the spring force of the spring 39, and the stopper pin 21 is brought into the operating position where it is fitted in the recess 18 b on the opposite side. As a result, the wedge body 15 connected by the crank cam 18 and the rod 22 moves downward, and the side surface 15b comes into pressure contact with the right side surface of the workpiece W. At this time, the spring force of the spring 39 also acts in the direction in which the wedge body 15 is pressed against the guide plate 14, so that the spring force of the spring 17 is overcome and the rack teeth 15a of the wedge body 15 and the rack teeth 14a of the guide plate 14 are overcome. Mesh with each other.

  Further, on the leg 13 side, the lock handle 34 is rotated counterclockwise about the shaft 35 against the spring force of the spring 38. As a result, when the connecting shaft 36 between the cam guide 33 and the lock handle 34 exceeds the straight line connecting the shaft 35 and the shaft 37, the spring force of the spring 38 causes the cam guide 33 to rotate clockwise at once, and its tip 33a Stop at the position where it hits the left side of the workpiece W. Along with this, the stopper cam 32 also rotates slightly clockwise about the shaft 31, but the engaging tooth 32 a is still buried in the leg 13 and does not enter the slot S. Or even if the engagement tooth 32a slightly enters the slot S, it does not hit at least the left side surface of the workpiece W, and there is a slight gap between them (see FIG. 2).

  When the suspension ring 28 is hung on a crane or the like in the state shown in FIG. And the engagement surface 24a of the presser foot 24 that is going to move in the direction of entering the slot S from the leg 13 side via the L link 25 and the presser link 30 as described above with the movement of the suspension ring 28; And is lifted in a state of being pressed and sandwiched between them and transported to a predetermined place.

  Here, even if the workpiece W is about to slide down during lifting and transporting, the workpiece sliding prevention device of the present invention composed mainly of the stopper cam 32 and the safety cam guide 33 is activated to prevent the workpiece W from falling. . That is, when the workpiece W is set as specified to the depth of the slot S, the cam guide tip 33a abuts against the left side surface of the workpiece W as described above. When the upper end slides down to a position below the cam guide tip 33a, the cam guide 33 enters a state where the tip 33a penetrates deeply into the slot S by the spring force of the spring 38 (FIG. 3). As the cam guide 33 further moves, the stopper cam 32 also rotates clockwise from the position shown in FIG. 2 about the shaft 31, so that the engaging tooth 32a enters the slot S and slides down. It bites into the left side of the workpiece W and prevents it from falling. When the upper end of the workpiece W slides down to a position below the cam guide tip 33a, the cam guide 33 rotates instantaneously and at high speed clockwise by the spring force of the spring 38 along with the in-slot movement of the cam guide 33. The engagement tooth 32a collides with the side surface of the workpiece W with a considerable impact force and bites into the workpiece W, thereby reliably preventing the workpiece W from dropping further.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this, and various modifications can be made within the scope of the invention defined in the claims. The workpiece sliding prevention device according to the present invention can be suitably applied to the intact clamp of the above-described embodiment, but can also be applied to other types and types of clamps and other transport devices and lifting devices.

It is a figure which shows the standby state of the intact clamp in which the workpiece | work slipping prevention apparatus by one Embodiment of this invention was integrated. It is a figure which shows the state which set the workpiece | work to this intact clamp. It is a figure which shows the state which the workpiece | work slip prevention apparatus worked in this intact clamp.

Explanation of symbols

S Slot W Work 10 Clamp body 12, 13 Leg 15 Wedge body 24 Presser foot 28 Suspension ring 30 Presser link 32 Stopper cam (Eccentric cam)
32a The engagement tooth 33 Safety cam guide (cam guide)
33a Its tip 34 Lock handle (switching means)
38 Spring (biasing means)

Claims (3)

In a clamp of the type in which the workpiece is set at a predetermined position in the slot and lifted by pressing the pressure contact members on both side surfaces thereof, a cam guide having a tip portion that can be inserted into the slot, and the tip portion of this cam guide as a slot And a biasing means for moving and biasing the cam guide in a direction to enter the cam guide, and an eccentric cam that rotates in conjunction with the movement of the cam guide, and when the workpiece is set at a predetermined position in the slot, the tip of the cam guide The eccentric cam is substantially buried in the clamp body at this time, and its engaging teeth are located away from the side surface of the workpiece. When the cam guide is positioned below the front end of the cam guide, the cam guide receives the biasing force of the biasing means and moves further into the slot. Characterized in that it is configured to prevent further sliding of the workpiece by causing bite the teeth by rotating the work side of the work sliding prevention device in the clamping. The eccentric cam is rotatable about a shaft fixed to the clamp body, and one end of the eccentric cam is pivotally connected to the other end of the cam guide so as to engage when the cam guide enters the slot. 2. The work slippage prevention device according to claim 1, wherein the device rotates in a direction in which the teeth enter into the slot. Switching means for switching between an operating position urged to move the cam guide in a direction to enter the slot by the urging means and a standby position urged to move in a direction opposite to the direction. The work slippage prevention device according to claim 1, wherein the work slippage prevention device is provided.

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