JP2010286336A - Gripper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gripper for fixing a pair of gripping teeth at any position if the gripping teeth are opened and closed by utilizing a fluid cylinder. <P>SOLUTION: The gripper is equipped with: a link mechanism for moving a pair of the gripping teeth 51 between a grip position and a release position; an air cylinder mechanism provided with the cylinder 31 and a piston 32; and a screw 42 for pressing an inclined section 34 formed in a protrusion 33 of the piston 32. The piston 32 is raised when the inclined section 34 formed in the protrusion 33 of the piston 32 is pressed by the screw 42 while a pair of the gripping teeth 51 is positioned at the release position, so that a pair of the gripping teeth 51 are synchronized with each other and moved against a bias force by a spring 66 in the approaching direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gripping tool for gripping a test piece in a material tester.

  As such a gripping tool, for example, a wedge-shaped gripping member having an inclined surface is moved along the chuck frame by driving a motor, and a test is performed using a gripping tooth on which a sawtooth-like unevenness is formed on the gripping member. The thing of the structure which hold | grips a piece is known (refer patent document 1).

  In addition, a gripping tool has been proposed in which the gripping teeth are normally opened by the action of a spring, and the gripping teeth are moved by a fluid cylinder when gripping the test piece (see Patent Document 2).

JP 2002-139411 A JP-A-5-332902

  When the tensile test is performed on the test piece, the test piece may be detached from the gripping teeth by being thinned (thinned) as the test piece is pulled. In such a case, if a gripping tooth using a wedge shape as described above is used, the gripping force by the gripping tooth increases according to the tensile force applied to the test piece. It is possible to prevent the occurrence of the phenomenon of coming off the gripping teeth.

  However, when such gripping teeth are used, for example, when a resin film or a thin metal film is used as the test piece, an excessive gripping force is applied to the test piece. In particular, the gripping force can be improved when the gripping teeth are formed with sawtooth-shaped irregularities, but when excessive gripping force is applied, the test piece is gripped. There is also the problem of being cut by the teeth.

  In order to solve such problems, the gripping part for gripping the test piece in the pair of gripping teeth is used as a gripping tool, and the gripping teeth are not gripped on the test piece. Sometimes it is separated by a spring, and when gripping a test piece, it uses a fluid cylinder mechanism such as an air cylinder to always press against the test piece with a constant force. Even when the piece is thin, the tensile test or the like can be performed without the test piece being detached from the gripping teeth and without damaging the test piece.

  However, when such a gripping tool is used, the pair of gripping teeth are arranged only at either a gripping position for gripping the test piece or a release position spaced apart from the gripping position. That is, the test piece is either firmly held by the pair of gripping teeth or not held at all.

  For this reason, when gripping the test piece with the gripping teeth, for example, the pair of gripping teeth are slightly closed and the test piece is positioned while holding the test piece with a light gripping force, and then the test piece is firmly held. It was impossible to use it.

  This invention was made in order to solve the said subject, and it aims at providing the holding tool which can fix a pair of holding teeth in arbitrary positions in the holding tool using a fluid cylinder. .

  The invention according to claim 1 is a gripping tool for gripping a test piece in a material testing machine, wherein a pair of gripping teeth and the pair of gripping teeth are held close to each other to grip the test piece. A gripping tooth moving mechanism that moves between a position and a release position that is spaced apart from the gripping position; and a fluid cylinder mechanism that moves the pair of gripping teeth to the gripping position in conjunction with the gripping tooth moving mechanism; A spring that urges the pair of gripping teeth toward the open position in conjunction with the gripping tooth moving mechanism; and the pair of gripping teeth in the state where the pair of gripping teeth are in the release position, It is characterized by comprising moving means for moving in a direction close to each other in synchronism with each other by a distance corresponding to the operation amount against the urging force of the spring.

  The invention according to claim 2 is the link mechanism according to claim 1, wherein the gripping tooth moving mechanism is pressed by a piston of the fluid cylinder mechanism to move the pair of gripping teeth to the gripping position. It is.

  According to a third aspect of the present invention, in the second aspect of the present invention, the moving means presses the piston, the link mechanism, or the gripping teeth so that the pair of gripping teeth correspond to the operation amount. It includes pressing means for moving in the direction of approaching each other by a distance of

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the moving means abuts against the inclined portion formed along the moving direction of the piston formed on the piston and the inclined portion. A pressing means for pressing the inclined portion, and the inclination direction of the inclined portion is a direction in which the piston presses the link mechanism when pressed by the pressing means.

  According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the pressing means is a screw that presses the inclined portion with its tip.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the fluid cylinder mechanism is an air cylinder mechanism, and the piston is pressed by the gripping tooth moving mechanism by the piston. A second spring that biases in the direction opposite to the direction is further provided.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to fifth aspects, the pair of gripping teeth has a flat holding portion for holding the test piece.

  According to the first aspect of the present invention, when a gripping tool that uses a fluid cylinder to grip a test piece with a constant force is used, a pair of gripping teeth can be fixed at an arbitrary position. Therefore, by adjusting the open state of the pair of gripping teeth, it is possible to easily execute adjustment of the gripping position of the test piece by the gripping teeth.

  According to the second aspect of the present invention, the pair of gripping teeth can be moved to the gripping position by operating the link mechanism by the piston of the fluid cylinder.

  According to the third aspect of the present invention, by pressing the piston, the link mechanism, or the pair of gripping teeth, the pair of gripping teeth are moved in the direction of the gripping position that is synchronized and close to each other by a distance corresponding to the operation amount. It becomes possible to make it. For this reason, it is possible to easily change the position of the gripping teeth.

  According to the fourth aspect of the present invention, by pressing the inclined portion with the pressing means, the piston presses the link mechanism, and the pair of gripping teeth are moved in synchronization with each other by a distance corresponding to the pressing amount. Is possible. For this reason, it is possible to easily change the position of the gripping teeth.

  According to the invention described in claim 5, by adjusting the amount of rotation of the screw, the pair of gripping teeth can be moved in synchronization with each other by a distance corresponding to the amount of rotation. For this reason, it becomes possible to change the position of the gripping tooth more easily.

  According to the sixth aspect of the invention, the test piece can be gripped with a constant force by the action of the air cylinder, and when the test piece is not gripped, the piston is grasped by the action of the spring and the pressing direction of the tooth moving mechanism is set. Can be moved in the opposite direction.

  According to the seventh aspect of the present invention, it is possible to execute gripping without damaging the test piece by the gripping teeth having a flat grip portion for gripping the test piece.

It is a schematic diagram of the material testing machine to which the gripping tool concerning this invention is applied. It is the longitudinal cross-sectional view which looked at the upper gripping tool 16 from the front. It is the longitudinal cross-sectional view which looked at the upper gripping tool 16 from the front. It is the fragmentary sectional view which looked at the upper gripping tool 16 from the side. It is an enlarged view which shows the relationship between the screw | thread 42 and the inclination part 34 grade | etc.,. It is an enlarged view which shows the relationship between the screw | thread 42 and the inclination part 34 grade | etc.,.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a material testing machine using the gripping tool according to the present invention will be described. FIG. 1 is a schematic view of a material testing machine to which a gripping tool according to the present invention is applied.

  The material testing machine includes a base 11, a pair of left and right screw rods 12 erected on the base 11, a yoke 13 disposed above the screw rods 12, and the pair of left and right screws. A nut portion that is screwed with the flange 12 is provided, and a crosshead 15 that is raised and lowered with respect to the screw rod 12 is provided. An upper grip 16 is attached to the cross head 15, and a lower grip 17 is attached to the base 11. The upper grip 16 and the lower grip 17 constitute a grip according to the present invention. Both ends of the test piece 18 are gripped by the upper grip 16 and the lower grip 17.

  Synchronous pulleys 19 that engage with the synchronous belt 21 are disposed at the lower ends of the pair of screw rods 12, respectively. The synchronous belt 21 is also engaged with a synchronous pulley 22 that is rotated by driving of a motor 23. For this reason, the pair of screw rods 12 rotate in synchronization with the drive of the motor 23. Then, as the pair of screw rods 12 rotate in synchronization, the cross head 15 moves up and down in the axial direction of the pair of screw rods 12.

  A load cell 24 is disposed between the crosshead 15 and the upper gripping tool 16, and the test force applied to the test piece 18 is detected by the load cell 24. Further, the displacement amount between the upper and lower gauge points of the test piece 18 is detected by the displacement meter 25. Signals from the load cell 24 and the displacement meter 25 are input to the control circuit 26. Then, the control circuit 26 creates a drive control signal for the motor 23 based on the signals from the load cell 24 and the displacement meter 25. Thereby, rotation of the motor 23 is controlled and various material tests, such as tension and compression, are performed.

  The position of the crosshead 15 is constantly monitored by the automatic stop mechanism 27. When the automatic stop mechanism 27 detects the movement of the crosshead 15 to a predetermined position, a stop signal is output to the motor 23, and the raising / lowering operation of the crosshead 15 is automatically stopped.

  Next, the structure of the gripping tool according to the present invention will be described. 2 and 3 are longitudinal sectional views of the upper grip 16 as viewed from the front. Here, FIG. 2 shows a state where the pair of gripping teeth 51 is in the release position, and FIG. 3 shows a state where the pair of gripping teeth 51 is in the gripping position. FIG. 4 is a partial cross-sectional view of the upper grip 16 as viewed from the side. In addition, the left half in FIG. 4 shows the longitudinal cross section which looked at the upper grip 16 from the side, and the right half has shown the side surface. Further, FIG. 5 is an enlarged view showing the relationship between the screw 42 and the inclined portion 34 and the like in FIG. FIG. 6 is an enlarged view showing the relationship between the screw 42 and the inclined portion 34 in FIG. The lower gripping tool 17 has a configuration similar to that of the upper gripping tool 16.

  In the upper grip 16, about half of the upper part constitutes an air cylinder mechanism, and about half of the lower part constitutes a link mechanism. That is, the upper gripping tool 16 includes a cylinder 31 that constitutes an air cylinder mechanism, a piston 32 that moves up and down in a space 37 formed in the cylinder 31, and an inner periphery of the cylinder 31 at an outer peripheral portion of the piston 32. And a packing 35 disposed in contact with the surface. A convex portion 33 for pressing a pair of rotating rollers 62 in a link mechanism to be described later is formed at the lower end portion of the piston 32, and an inclined portion 34 to be described later is formed on the convex portion 33.

  A spiral spring 38 is disposed below the cylinder 31. The spring 38 biases the piston 32 in the direction opposite to the direction in which the rotary roller 62 is pressed by the piston 32 (the upward direction shown in FIGS. 2 to 4). A space 37 formed in the cylinder 31 is connected to a pump 71 that is a supply source of compressed air via a flow path 36 and a pipe path 73 (see FIG. 4). Further, as shown in FIG. 4, an electromagnetic on-off valve 72 having a leak function is disposed in the pipe 73. For this reason, when the electromagnetic on-off valve 72 is opened, compressed air is supplied into the space 37 formed in the cylinder 31 and the piston 32 descends. Further, when the electromagnetic opening / closing valve 72 is closed, the piston 32 is raised by the action of the spring 38.

  The link mechanism is housed in a casing 41 that forms the lower part of the upper gripping tool 16. The pair of rotating rollers 62 pressed by the convex portion 33 of the piston 32 described above functions as a roller type cam follower, and is attached to the end portions of the pair of arms 61 that can slide the guide grooves formed in the casing. It is attached. A pin 63 is erected on the end of the arm 61 opposite to the rotating roller 62. In addition, a pair of arms 64 that can swing around a shaft 65 disposed in the casing 41 is disposed. One end of the arm 64 is formed with a long hole that engages with a pin 63 erected on the arm 61, and a guide groove formed in the casing 41 can slide on the other end of the arm 64. A long hole that is engaged with a pin 68 erected on a pair of arms 69 is formed.

  Of the pair of arms 69, a shaft 52 facing in the vertical direction is disposed at the tip of the arm 69 shown on the right side in FIGS. 2 and 3. The support portion 54 of the gripping tooth 51 shown on the right side in FIGS. 2 and 3 has a configuration that rotates around the shaft 52. For this reason, this gripping tooth 51 swings around a shaft 52 oriented in the vertical direction. On the other hand, of the pair of arms 69, a shaft 53 that faces in the horizontal direction is disposed at the tip of the arm 69 shown on the left side in FIGS. 2 and 3, the support portion 55 of the gripping tooth 51 shown on the left side has a configuration that rotates around the shaft 53. For this reason, this gripping tooth 51 swings around a shaft 53 that faces in the horizontal direction.

  In the pair of gripping teeth 51, a gripping portion for gripping the test piece 18 is planar. Therefore, even when the gripping teeth 51 grip the test piece 18 made of a resin film or a thin metal film, the planar gripping portion grips the test piece 18 uniformly in the planar area. The test piece 18 is not damaged.

  In the casing 41, a pair of springs 66 that are in contact with the pair of arms 64 are disposed. These springs 66 urge the arm 64 swinging about the shaft 65 in a direction in which the pair of gripping teeth 51 are separated from each other and move toward the open position. That is, of the pair of springs 66, the spring that abuts on the right arm 64 shown in FIGS. 2 and 3 urges the arm 64 in the counterclockwise direction, as shown in FIGS. The spring in contact with the left arm 64 biases the arm 64 in the clockwise direction.

  An inclined portion 34 is formed on the convex portion 33 of the piston 32. 2, 3 and 5, the inclined portion 34 has a shape extending along the reciprocating direction of the piston 32, and as shown in FIGS. 4 and 6, the inclined surface is on the upper side. The shape is closer to the center of the convex portion 33. A screw 42 is screwed into a screw hole formed in the casing 41. The tip of the screw 42 is in contact with the inclined surface of the inclined portion 34.

  As shown in FIGS. 2, 4, 5, and 6, the operator rotates the screw 42 in a state where the piston 32 is disposed in the raised position and the pair of gripping teeth 51 are in the released position. When the inclined surface of the inclined portion 43 is pressed by the tip of the piston 32, the piston 32 is lowered by the action of the inclined surface. As the piston 32 descends, the convex portion 33 of the piston 32 presses the pair of rotating rollers 62 in the link mechanism. Along with this, the pair of gripping teeth 51 moves in directions approaching each other. The amount of movement of the pair of gripping teeth 51 at this time is proportional to the amount of movement of the tip of the screw 42, that is, the amount of rotation of the screw 42.

  A gripping operation when gripping the test piece 18 in the upper gripping tool 16 having the above configuration will be described. The lower gripping tool 17 has the same configuration as the upper gripping tool 16, and grips the test piece by the same operation.

  In the first stage, the electromagnetic on-off valve 72 shown in FIG. 4 is closed, and compressed air is not fed into the space 37 formed in the cylinder 31. Therefore, as shown in FIGS. 2 and 4, the piston 32 is stopped at the upper end of the stroke by the action of the spring 38. In this state, as shown in FIGS. 2 and 4, the pair of gripping teeth 51 are stopped at the release position.

  In this state, the test piece 18 is disposed between the pair of gripping teeth 51. Then, by rotating the screw 42, the tip of the screw 42 presses the inclined surface of the inclined portion 34 formed on the convex portion 33 of the piston 32. The piston 32 is lowered by the pressing force of the screw 42 acting on the inclined surface of the inclined portion 34. Then, as the piston 32 descends, the convex portion 33 presses the pair of rotating rollers 62. This pressing force is transmitted to the pair of gripping teeth 51 via the arm 61, the arm 64, and the arm 69, and the pair of gripping teeth 51 moves toward each other against the biasing force of the spring 66. The amount of movement of the gripping teeth 51 at this time is proportional to the amount of movement of the tip of the screw 42, that is, the amount of rotation of the screw 42.

  When the pair of gripping teeth 51 move in a direction approaching each other and the test piece 18 is gripped by the gripping teeth 51 with a light force, the test piece 18 is positioned and the like. And if the test piece 18 is hold | gripped appropriately, the electromagnetic on-off valve 72 shown in FIG. 4 will be open | released. Thereby, compressed air is sent into the space 37 formed in the cylinder 31, and the piston 32 descends with a large force by the compressed air. As the piston 32 descends, the convex portion 33 presses the pair of rotating rollers 62. This pressing force is transmitted to the pair of gripping teeth 51 via the arm 61, the arm 64, and the arm 69, and the pair of gripping teeth 51 grips the test piece 18 with a large force of compressed air.

  At this time, as described above, one gripping tooth 51 swings around a shaft 52 that faces in the vertical direction, and the other gripping tooth 51 swings around a shaft 53 that faces in the horizontal direction. Regardless of the shape of 18, this can be reliably gripped by the pair of gripping teeth 51. And since the planar holding part in the grasping tooth 51 holds the test piece 18 uniformly in the planar area, the test piece 18 is not damaged.

  At this time, the pair of gripping teeth 51 has moved in advance to a position where the test piece 18 can be lightly gripped by the action of the screw 42 or the like. For this reason, there is no danger that an operator's finger etc. will be pinched by a pair of grasping teeth 51, when grasping with big force by compressed air.

  By such an operation, after the test piece is securely gripped by the upper gripping tool 16 and the lower gripping tool 17, the pair of screw rods 12 are rotated synchronously by driving the motor 23 shown in FIG. A tensile test is performed by moving up and down. At this time, even if a phenomenon that can be eliminated by pulling the test piece 18 occurs, the pair of gripping teeth 51 always holds the test piece with a constant force by the action of the air cylinder mechanism. Even if the grip portion of the test piece 18 is planar, the test piece 18 does not come off from the pair of gripping teeth 51.

  When the necessary test is completed, the electromagnetic on-off valve 72 is opened and the compressed air is discharged from the space 37 formed in the cylinder 31. Along with this, the piston 32 is raised by the action of the spring 38. The piston 32 stops at a position where the pressing force by the screw 42 acts on the inclined surface of the inclined portion 34. In this state, the operator supports the test piece 18 and loosens the screw 42. Accordingly, the pair of gripping teeth 51 are moved away from each other to the release position by the action of the spring 66.

  In the above-described embodiment, by pressing the inclined surface of the inclined portion 43 formed on the piston 32 by the tip of the screw 42, the pair of gripping teeth 51 are mutually connected by a distance corresponding to the rotation amount of the screw 42. The structure which makes it adjoin by synchronizing is employ | adopted. However, instead of pressing the inclined portion 43 with the screw 42, by pressing any one of the arm 61, the arm 64, and the arm 69 constituting the link mechanism, or the pair of gripping teeth 51 themselves, the pair of gripping teeth 51 It is good also as a structure which moves. However, it is necessary to adopt a configuration in which the pair of gripping teeth 51 are moved by the same distance in synchronization with each other.

  In the above-described embodiment, the screw 42 is used as the pressing means for pressing the inclined portion 43, but other pressing means using a ratchet or the like may be used. However, the mechanism is required to be capable of moving the pair of gripping teeth 51 by a certain amount by pressing the inclined surface of the inclined portion 43 with a certain operation amount.

  Furthermore, in the embodiment described above, the screw 42 is manually rotated by the operator, but the screw 42 may be rotated by a motor or the like.

DESCRIPTION OF SYMBOLS 11 Base 12 Screw rod 13 Yoke 15 Cross head 16 Upper grip 17 Lower grip 18 Test piece 21 Synchronous belt 23 Motor 24 Load cell 25 Displacement meter 26 Control circuit 27 Automatic stop mechanism 31 Cylinder 32 Piston 33 Protrusion 34 Inclination 35 Packing 36 Flow path 38 Spring 41 Casing 42 Screw 51 Grasp 52 Shaft 53 Shaft 54 Support section 55 Support section 61 Arm 62 Rotating roller 63 Pin 64 Arm 65 Shaft 66 Spring 68 Pin 69 Arm 72 Electromagnetic switching valve

Claims (7)

A gripping tool for gripping a test piece in a material testing machine,
A pair of gripping teeth;
A gripping tooth moving mechanism for moving the pair of gripping teeth between a gripping position for gripping the test piece in proximity to each other and a release position spaced apart from the gripping position;
A fluid cylinder mechanism that moves the pair of jaw teeth to the gripping position in conjunction with the jaw movement mechanism;
A spring that urges the pair of jaws toward the open position in conjunction with the jaw movement mechanism;
Moving means for moving the pair of gripping teeth in a direction close to each other in synchronization with each other by a distance corresponding to an operation amount against the biasing force of the spring in a state where the pair of gripping teeth are in the release position. When,
A gripping tool characterized by comprising: The gripping tool according to claim 1,
The gripper moving mechanism is a gripper that is a link mechanism that is pressed by a piston of the fluid cylinder mechanism to move the pair of gripping teeth to the gripping position. The gripping tool according to claim 2,
The moving means includes a pressing means that presses the piston, the link mechanism, or the gripping teeth to move the pair of gripping teeth in a direction close to each other in synchronization with each other by a distance corresponding to an operation amount. Ingredients. The gripping tool according to claim 3,
The moving means is
An inclined portion formed along the moving direction of the piston formed in the piston;
Pressing means for contacting the inclined portion and pressing the inclined portion;
A gripping tool in which the inclination direction of the inclined portion is a direction in which the piston presses the link mechanism when pressed by the pressing means. The gripping tool according to claim 4,
The pressing means is a gripping tool that is a screw that presses the inclined portion with its tip. The gripping tool according to any one of claims 1 to 5,
The fluid cylinder mechanism is an air cylinder mechanism;
A gripping tool further comprising a second spring that biases the piston in a direction opposite to a pressing direction of the gripping tooth moving mechanism by the piston. The gripping tool according to any one of claims 1 to 5,
The pair of gripping teeth is a gripping tool in which a grip portion for gripping the test piece is planar.

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