JPH0375317B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a flexible grasping mechanism that has adaptability to the shape of a workpiece and flexibility due to stress distribution during grasping, can adapt to any shape, and is capable of grasping a workpiece with equal pressure.

[Prior art]

As a conventional flexible grasping mechanism, the
13874, etc., and as shown in FIGS. 3 and 4, a large number of link plates 2 are used.
A cable-like grasping body 21 is constructed from a multi-segment body 22 formed by rotatably connecting the joints 3 and 12 with each other, and holds this in a cantilevered manner with one end as a supporting end and the other end as a free end. An actuator for generating gripping torque is disposed at each node of the gripping body 21, and the torque generated by the actuator is quadratic from the supporting end toward the free end along the axial length of the multi-jointed body 22. This is the basic structure designed to reduce the In this way, the entire gripping body 21 can grip the workpiece with a uniform force, and the pulley and wire system can generate torque under predetermined conditions at each joint. Alternatively, for the torque transmission wheel of a chain sprocket, the minimum radius of curvature is fixed depending on the size of the wire 26 or the chain, so there is a limit to the minimum winding radius, and even if you try to reduce it, you cannot reduce it below the limit, so it is difficult to grasp it. The width dimension parallel to the direction of motion increases, and the overall size of the hand increases accordingly, which poses a problem in terms of making it compact. Further, when a small-diameter torque transmitting member such as the wire 26 is used, it must be wrapped around the torque transmitting wheel to prevent slippage, complicating assembly work.

[Purpose of the invention]

The present invention has been developed in response to the above-mentioned circumstances.The present invention aims to make the structure of the hand portion more compact, and has a simple structure that facilitates manufacturing and reduces costs. The purpose is to provide a flexible grasping mechanism with a wide range of functions.

[Structure of the invention]

In order to achieve the above-mentioned object, the present invention provides a cable-like grasping body using a multi-jointed body in which a large number of link plates are articulated to each other via pins in the form of a roller chain that can rotate at each joint. The grasping side pulley and the releasing side pulley are fitted onto the pins of each node so as to be rotatable with respect to each link plate, and the pins are respectively spanned between the central portions of the opposing link plates. The grasping-side intermediate pulley and the releasing-side intermediate pulley are rotatably coaxially supported on each pin, while one end of the grasping flat belt is fixed to the free end that becomes the tip of the multi-section body, and After the gripping side pulley and the gripping side intermediate pulley are stretched in an alternating meandering manner to reach the supporting end side which becomes the base of the multi-sectioned body, the other end is connected to a tension actuator such as a motor to transmit the gripping torque. formed into a member,
Further, one end of the restoring flat belt is fixed to the free end of the multi-section body, and the restoring flat belt is stretched around the release-side pulley and the release-side intermediate pulley in an alternating meandering manner to reach the support end side of the multi-section body. After this, the other end is connected to a means for applying a constant tension such as a spring to form a restoring torque transmitting member, and furthermore, the difference in diameter of the grasping side pulley at each joint is adjusted from the supporting end to the free end. The diameter of each grasping-side pulley and each release-side pulley is set to gradually decrease in a quadratic manner, and when the tension actuator is operated, the diameter of each grasping-side pulley is The gripping torque gradually decreases in a quadratic manner from the support end to the free end of the multi-joint body, and the contact force when each link plate contacts the circumferential surface of the workpiece in an enveloping manner increases. It is possible to equalize, and
Structurally, since a flat belt is used as a torque transmission member, there is less slippage and the allowable radius of curvature can be reduced, so the diameter of each pulley can be made smaller and the overall shape can be made more compact. It is something to tighten.

【Example】

The configuration of one embodiment of the present invention will be explained based on FIGS. 1 and 2. FIG. The flexible grasping mechanism shown in the figure includes a cable-shaped grasping body 1 formed from a multi-segment body 2 formed by jointing a large number of link plates 3, 3 through pins 4, 4 in the form of a mutually rotatable roller chain; Side pulley 5, 5
, release-side pulleys 6, 6, grip-side intermediate pulleys 8, 8, release-side intermediate pulleys 9, 9, gripping flat belt 10, release flat belt 11, tension actuator 12, and spring 13. and restoring tension applying means as element members. The link plates 3 are made of metal plate pieces, and are gradually shortened from the supporting end, which is the base of the multi-section body 2, to the free end, which is the tip. It is formed into a plate piece whose width gradually becomes narrower toward the tip on the free end side, and holes into which the pins 4 are inserted are bored at both ends. It should be noted that each ring crate 3 is shaped such that the diameter dimension in the plate surface direction at both ends is slightly larger than the diameter of the grasping pulley 5 fitted to the pin 4 at the corresponding location. Also, the link plate 3 serving as the supporting end, that is, the link plate 3 located at the left end in FIGS.
The large diameter side is rotatably attached to the holding member 15 by the pin 4. A flanged grasping pulley 5 and a releasing pulley 6 are respectively fitted onto the pins 4, 4 of the link plates 3, 3, and are rotatable relative to the link plates 3. . Further, each of the link plates 3, 3 has a pin hole bored in its center, and a pin 7 is passed between the opposing link plates 3, 3, respectively.
A grasping-side intermediate pulley 8 and a releasing-side intermediate pulley 9 are individually rotatable with respect to each pin 7, and are pivotally supported in the same line as the grasping-side pulley 5 and the releasing-side pulley 6, respectively. Next, the grasping flat belt 10 is a thin sheet-like material having a core material made of a tensile wire such as an ultra-thin diameter piano steel wire, and is of an appropriate length, and one end is attached to the most advanced pin 4. The gripping side pulley 5 and the gripping side intermediate pulley 8 are fixed to the protruding piece 19 as a free end that is supported by gluing or screwing.
The other end is wound around a pulley 16 for winding. The pulley 16 is fitted onto the output shaft of a tension actuator 12 consisting of a servo motor 14 and a speed reducer 18. When power is supplied to the servo motor 12, the grasping flat belt 10 is wound around the winding pulley 16. On the other hand, when the power supply is cut off, the flat belt 10 becomes rotatable integrally with the actuator 12, and the tension applied to the flat belt 10 disappears. On the other hand, the restoring flat belt 11 is made of a sheet-like material of the same quality as the gripping flat belt 10 or a rubber sheet-like material having elasticity, and has an appropriate length, and one end is fixed to the protruding piece 19. Further, after being wound around the release pulley 9 in a meandering manner in which the winding direction alternates to reach the holding member 15, the other end is wound around the winding pulley 17. The pulley 17 is a winding pulley 17 in order to apply a constant tension such as a spring 13 to the flat belt 11.
It is fitted onto the output shaft of a means for applying a force in the winding direction to the restoring flat belt 11, and the elasticity of the spring 13 always applies a constant winding tension to the restoring flat belt 11. Note that the tension actuator 12 is not limited to a rotation mechanism, and may be a linear motion mechanism such as a pneumatic cylinder. Further, in addition to the spring 13, a constant torque motor, a pneumatic cylinder, etc. can be used as the tension applying means. By tensioning both the flat belts 10 and 11 in this way, a constant force is applied to the outer periphery of the gripping pulley 5 by the tension actuator 12, while a constant force is applied to the release pulley 6 by the spring 13. The force of will come into play. The outline of the structure of the flexible grasping mechanism is as explained above, and when power is supplied to the actuator 12, the grasping flat belt 10 moves to the winding pulley 1.
6 and pulled toward the holding member 15 side, the multi-section body 12 is bent in a direction that shortens the extended length of the grasping flat belt 12, and is not able to handle round objects. On the other hand, if there is no work and it is placed in the deployment space, it will curve into a curled shape, and conversely, when the power supply to the actuator 12 is cut off, the restoring flat belt 11 will spring into the spring 13. Holding member 15 by
By being pulled to the side, the multi-segmented body 2 becomes curled in the opposite direction to the grasping direction. Here, the mechanical principle for grasping the round workpiece with equal pressure from the surroundings by the grasping body 1 is as described in detail in Japanese Patent Publication No. 13874/1983, and is grasped with equal pressure. The gripping torque applied to the actuating member that brings the side edges of the link plates 3, 3 into contact with the workpiece, that is, each gripping pulley 5, is preferably applied from the holding member 15 along the longitudinal direction of the gripping body 1. It has been found that it is sufficient to set it so that it gradually decreases in a quadratic function in the process of reaching piece 19. Therefore, it is only necessary to specify the structure so as to satisfy the above-mentioned torque setting conditions, and the gripping torque generated at the point where the flat belt 10 contacts the outer periphery of the gripping pulley 5 is transferred from the holding member 15 serving as the supporting end. In order to decrease the diameters of the grasping side pulley 5 and the release side pulley 6 at each node as a quadratic function in order to reach the protruding piece 19 that becomes the free end, the difference in diameter between the grasping side pulley 5 and the release side pulley 6 is calculated as a quadratic function as it moves from the supporting end to the free end. It has a structure that gradually decreases. Here, since it is naturally necessary to make the grasping torque sufficiently larger than the release torque, it goes without saying that the diameter of the pulley is larger on the grasping side pulley 5, and it goes without saying that the diameter of the pulley is larger on the grasping side pulley 5. Both diameters may be made equal at the portion. By doing so, it is possible to make the gripping torque uniform over the entire range from the supporting end to the free end when gripping the workpiece. Note that since the torque on the release side does not need to be the same as the torque setting condition on the grasping side, each release pulley 6 is formed to have the same diameter so that the restoring torque is constant. Next, to explain the grasping operation by the above-mentioned grasping mechanism, when the actuator 12 is actuated to apply winding tension to the grasping flat belt 10, each pin 4, 4 is moved by a spring via the restoring flat belt 11 and the release pulley 6. The direction in which the workpiece is wrapped by overcoming the restoring torque applied from 13, that is, the flat belt 1
It bends in a direction that shortens the extended length of 0, and curves to envelop the workpiece. At this time, the link plate 3 and the grasping flat belt 1
0 is a state in which the flat belt 10 is fixed to the link plate 3 because the movement of each link plate 3, 3 is restrained by the workpiece, and the grasping flat belt 10 is pulled in to the limit and cannot move any more. Therefore, torque acts on each node of the link plates 3, 3. As mentioned above, this torque decreases in a quadratic manner from the supporting end side to the free end side, and on the other hand,
Since the torque exerted by the restoring flat belt 11 is constant at each joint, the gripping distribution force exerted on the workpiece by the link plates 3, 3 becomes uniform, making it possible to grip the workpiece in a flexible state. Next, when releasing the grip, use actuator 1.
By releasing the action of 2 and making the flat belt 10 into a free state, the tension on the gripping flat belt 10 is almost eliminated, and the restoring flat belt 11 by the spring 13 is released.
The tension is overcome and the link plates 3, 3 separate from the workpiece and bend to the opposite side. At this time, release starts first from the tip side and gradually moves to the support end side. Then, the final curled position is reached,
When bending toward the work gripping side, the bending starts from the supporting end and gradually moves to the free end. In addition, since the restoring torque at the time of restoring is performed by the spring 13, the restoring torque may decrease toward the tip due to friction in each pulley 6, 9, so the restoring flat belt 11 is provided with elasticity as described above. It is effective to keep the torque constant by using a stretchable flat belt. Further, the intermediate pulleys 8 and 9 are used to increase the angle at which the flat belts 10 and 11 are wrapped around the pulleys 5 and 6, thereby eliminating slippage.

【Effect of the invention】

(a) As the grasping torque transmission member and restoring torque transmission member have excellent flexibility and can reduce the allowable radius of curvature, it is possible to sufficiently reduce the diameters of the grasping side pulley 5 and the release side pulley 6; By narrowing the width dimension of the link plates 3, 3 parallel to the direction of grasping operation, the hand portion can be made more compact. (b) The hand part has a roller chain-like structure,
flat belt 10 for each pulley 5, 6, 8, 9;
11 in an alternating meandering pattern, it is easier to assemble than conventional methods such as wire winding.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional front view of essential parts according to one example of the present invention, with the grasping flat belt and the restoring flat belt omitted. FIG. 2 is also a plan view showing a part of the multi-segmented body. 3 and 4 are a plan view and an enlarged sectional view of the main parts of a conventional grasping mechanism. 1... Grasping body, 2... Multi-segment body, 3... Link plate, 4... Pin, 5... Grasping side pulley, 6...
...Release side pulley, 7...Pin, 8...Grasping side intermediate pulley, 9...Release side intermediate pulley, 10...Flat belt for grasping, 11...Flat belt for restoring, 12...
Tension actuator, 13... spring.

Claims (1)

[Claims] 1 A cord-shaped gripping body 1 is formed by a multi-segmented body 2 formed by jointing a large number of link plates 3, 3 in a rotatable roller chain shape with each other via pins 4, 4, and a gripping side pulley 5 and release The side pulleys 6 are fitted onto the pins 4 of each part so as to be rotatable with respect to each link plate, and a pin 7 is provided between the central parts of the opposing link plates 3, 3, respectively.
A grasping-side intermediate pulley 8 and a release-side intermediate pulley 9 are rotatably supported on each pin 7, while a grasping flat belt 10 is fixed at one end to the free end that becomes the tip of the multi-section body 2, After passing it around the gripping side pulley 5 and the gripping side intermediate pulley 8 in an alternating meandering manner to reach the support end side which becomes the base of the multi-section body 2, the other end is connected to a tension actuator 12 such as a motor. The restoring flat belt 11 is formed into a grasping torque transmitting member, and one end of the restoring flat belt 11 is fixed to the free end of the multi-segmented body 2, and is stretched around the release-side pulley 6 and the release-side intermediate pulley 9 in an alternating meandering manner. After reaching the support end side of the multi-joint body 2, the other end is connected to a means for applying a constant tension such as a spring 13 to form a restoring torque transmission member, and furthermore, the grasping side pulley 5 at each joint
The diameters of each grasping-side pulley 5 and each releasing-side pulley 6 are set so that the difference between the diameters of each grasping-side pulley 5 and each releasing-side pulley 6 gradually decreases from the support end to the free end in a quadratic manner.
The gripping torque generated on the outer periphery of each gripping pulley 5 when the tension actuator 12 is actuated gradually decreases quadratically from the support end to the free end of the multi-articulated body 2. A flexible grasping mechanism featuring: