Gripping device

Abstract

This gripping device (1) comprises: a gripping claw unit (3); a gripping mechanism (4) that supports the gripping claw unit (3) so the gripping claw unit can operate in an opening / closing direction (C1), and that rotates about a rotation axis (C) parallel to the opening / closing direction (C1); an opening / closing driving source (5) that opens / closes the gripping claw unit (3); and a rotation driving source that rotates the gripping claw unit (3) around the rotation axis (C). The gripping claw unit (3) has a pair of gripping claws (8, 8) and a gripping claw coupling mechanism (25) for coupling portions of the gripping claws (8, 8). The gripping mechanism (4) includes: a swinging rotation shaft (17) that supports one of the gripping claws (8) and rotatably supports the entire gripping claw unit so that the gripping claw unit can swing about the rotation axis (C); and an opening / closing mechanism (9) including linear movement elements (11, 11) that allow the pair of gripping claws (8, 8) to move freely in the opening / closing direction (C1). The linear movement elements (11, 11) and the swinging rotation shaft (17) cooperate to open and close the pair of gripping claws (8, 8) by means of the opening / closing driving source (5).

Description

gripping device Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2024-083458, filed May 22, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a gripping device that grips a workpiece such as a mechanical part or an electronic part.

[0003] In a hand installed at the tip of a multi-joint robot or the like, the claws are opened and closed in a linear direction to grasp a workpiece, and the posture of the workpiece can be changed while it is being grasped by the claws (for example, Patent Documents 1 and 2).

[0004] The hand of Patent Document 1 has a rotatable nut attached to a shaft extending in the opening and closing direction of the gripping jaws, and rotation is transmitted to the gripping jaws via this nut, causing the gripping jaws to swing while gripping a workpiece.The hand of Patent Document 2 has a nut threadedly engaged with a ball screw extending in the opening and closing direction of the gripping jaws, and rotation is transmitted to the gripping jaws via this nut, causing the jaws to swing while gripping a workpiece.

[0005] Patent No. 5617512 Patent No. 6029561

[0006] In the hands of Patent Documents 1 and 2, the gripping jaws can be adjusted to a direction that makes gripping easier before gripping the workpiece. This adjustment is effective when gripping irregularly stacked workpieces. In this case, the angles of the pair of gripping jaws must move in sync to grip the workpiece. In conventional structures, a mechanism is provided that distributes power from a single drive source to both gripping jaws, or independent mechanisms are driven simultaneously to operate the pair of gripping jaws simultaneously. In this case, the hand becomes heavy and large.

[0007] An object of the present invention is to provide a gripping device that can be made lighter and more compact than conventional structures.

[0008] The gripping device of the present invention comprises a gripping jaw unit that operates in an opening and closing direction to grip and release a workpiece; a gripping mechanism that supports the gripping jaw unit so that it can operate in the opening and closing direction and rotates around a rotation axis parallel to the opening and closing direction; an opening and closing drive source that drives the gripping jaw unit to open and close; and a rotation drive source that drives the gripping jaw unit to rotate around the rotation axis, wherein the gripping jaw unit has a pair of gripping jaws and a gripping jaw connecting mechanism that connects parts of the gripping jaws, and the gripping mechanism includes: an oscillating rotation shaft that supports either one or both of the gripping jaws and rotatably supports the entire gripping jaw unit so that it can oscillate around the rotation axis, and an opening and closing mechanism that includes a linear motion element that allows the pair of gripping jaws to move freely in the opening and closing direction, and the linear motion element and the oscillating rotation shaft work together to drive the pair of gripping jaws to open and close by the opening and closing drive source.

[0009] With this configuration, the gripping jaw unit can be oscillated and rotated while the pair of gripping jaws grips the workpiece. Therefore, the workpiece can be oscillated and rotated without operating the work machine to which this gripping device is connected. Because the main objects of rotation are the workpiece and the gripping jaws, the weight and moment of inertia of the objects of rotation are reduced. As a result, the work machine can rotate at high speeds.

[0010] The oscillating rotation shaft supports one or both gripping jaws and rotatably supports the entire gripping jaw unit, and the gripping jaw unit is rotationally driven by a rotation drive source. The pair of gripping jaws are driven to open and close by the opening and closing drive source, with the linear motion element and the oscillating rotation shaft working together. This eliminates the need for a mechanism that distributes rotational power from a single drive source to both gripping jaws, or a drive source that simultaneously rotates independent mechanisms, as in the conventional structure described above, and allows the entire gripping device to have a simpler structure than the conventional structure. This allows the gripping device to be lighter and more compact than the conventional structure.

[0011] The gripping mechanism may include a rotation mechanism that rotatably supports the gripping jaw unit about the rotation axis, and this rotation mechanism may have an extension / retraction rotation mechanism that transmits the rotation of the rotation drive source to the swing rotation shaft and enables the swing rotation shaft to move in the opening / closing direction. In this case, rotation transmission while the gripping jaw unit is moving in the opening / closing direction, rotation transmission while stopped at two points before and after the extension / retraction movement, and rotation transmission at any point during the extension / retraction movement are all possible.

[0012] The rotation drive source may be a motor, in which case the orientation of the workpiece can be easily changed to any desired inclination.

[0013] The swing rotation shaft may be provided with a gripping jaw detachable member that detachably supports one of the gripping jaw units, allowing the gripping jaw unit to be easily replaced depending on the shape of the workpiece, the conditions of use of the gripping device, etc.

[0014] The gripping claw coupling mechanism has a restoring force that allows one of the gripping claws to elastically deform relative to the other gripping claw, a pressing member that abuts against and moves away from the other gripping claw is provided on the linear moving element at a portion facing the other gripping claw, the opening / closing drive source may move the linear moving element in one opening / closing direction, causing the pressing member to abut against the other gripping claw against the restoring force, thereby placing the pair of gripping claws in a closed state, and the opening / closing drive source may move the linear moving element in the other opening / closing direction, thereby placing the pair of gripping claws in an open state by the restoring force.

[0015] In this case, for example, ordinary tweezers can be retrofitted as a pair of gripping jaws having the gripping jaw connection mechanism with the restoring force. This allows the approach angle to the workpiece to be changed using only the tip of the gripping device, for example, when picking bulk items, and makes it possible to avoid interference between the gripping device and work machines such as robots in extremely small spaces. Furthermore, retrofitting tweezers reduces the manufacturing cost of the gripping device compared to designing a new dedicated gripping jaw unit.

[0016] The gripping claw unit may have a passive rotation shaft that rotatably supports the other gripping claw on the gripping mechanism. In this case, one gripping claw is rotatably supported on the swingable rotation shaft, and the other gripping claw is rotatably supported on the gripping mechanism via the passive rotation shaft. In this way, since the pair of gripping claws are rotatably supported on the gripping mechanism, the rigidity of the gripping claw unit can be increased and undesired tilting of the gripping claws, misalignment of the open / closed positions, etc. can be prevented.

[0017] The telescopic rotation mechanism includes an input shaft to which rotation of the rotation drive source is transmitted and which is supported for rotation about the rotation axis, an output shaft which is supported for rotation parallel to the input shaft, a first gear provided on the input shaft, and a second gear provided on the output shaft which meshes with the first gear and to which the rotational force of the first gear is transmitted and which is movable relative to the first gear in an axial direction parallel to the opening and closing direction, wherein either one of the first and second gears may have an axial dimension longer than the opening and closing width of the gripping mechanism. In this case, with a small number of parts, rotational torque can be reliably transmitted from the input shaft to the output shaft, and the output shaft can be moved in the telescopic direction, which is the axial direction.

[0018] The telescopic rotation mechanism may have a sliding bearing that supports the output shaft so that it can slide freely in the axial direction. In this case, the rotation of the output shaft can be maintained while the output shaft can slide in the axial direction with a simple structure. Furthermore, the output shaft is less likely to wear than in a structure without a sliding bearing, which improves the durability of the telescopic rotation mechanism.

[0019] The power transmission mechanism of the rotation mechanism may be a combination of pulleys and a belt. In this case, the rotation speed of the oscillating rotation shaft and the distance between the input and output shafts can be adjusted by changing the diameter of the pulleys and the length of the belt. This increases the degree of freedom in the capacity and arrangement of the rotation drive source.

[0020] The power transmission mechanism of the rotation mechanism may be a spur gear. In this case, the rotation speed of the oscillating rotation shaft and the distance between the input and output shafts can be adjusted by changing the diameter and number of teeth of the spur gear. This increases the degree of freedom in the capacity and arrangement of the rotation drive source.

[0021] The gripping mechanism may have a detachable connecting part at the tip of the work machine. In this case, it is easy to replace the opening / closing mechanism with one having a different opening / closing stroke, for example, depending on the application of the work machine, the work, etc., thereby reducing the amount of work required.

[0022] Any combination of at least two features disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of the claims is included in the present invention.

[0023] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present invention, which is defined by the appended claims. In the accompanying drawings, the same reference numerals in multiple drawings indicate the same or corresponding parts.

[0024] 1 is a perspective view of a gripping device according to a first embodiment of the present invention. FIG. 2 is a front view of the gripping device. FIG. 3 is a front view showing a modified example of a rotation mechanism of the gripping device. FIG. 4 is a right side view of the gripping device. FIG. 5 is a left side view of the gripping device. FIG. 6 is a front view of a rotation drive source and an extendable rotation mechanism of the gripping device. FIG. 7 is a left side view of the rotation drive source and the extendable rotation mechanism. FIG. 8 is a cross-sectional view taken along line VII-VII of FIG. 6. FIG. 9 is a perspective view of a gripping claw unit of the gripping device. FIG. 10 is a perspective view of a gripping device with the gripping claw unit in a closed state. FIG. 11 is a front view of a gripping device with the gripping claw unit in a closed state. FIG. 12 is a perspective view of a gripping device according to a second embodiment of the present invention. FIG. 13 is a front view of the gripping device. FIG. 14 is a front view of a gripping device with the gripping claw unit in a closed state. FIG. 15 is a perspective view of a gripping device according to a third embodiment of the present invention. FIG. 16 is a perspective view of a gripping claw unit of the gripping device. FIG. 17 is a perspective view of a gripping device according to a fourth embodiment of the present invention. FIG. 18 is a cross-sectional view of a main part of the gripping claw unit. FIG. 19 is a perspective view of a gripping device with the gripping claw unit in a closed state. FIG. 19 is a perspective view of a gripping device according to a fifth embodiment of the present invention. Fig. 10 is a perspective view of a gripping claw unit of the gripping device. Fig. 11 is a cross-sectional view of a main part of the gripping claw unit. Fig. 12 is a cross-sectional view of a main part showing a first modified example in which the gripping claw unit is partially modified. Fig. 13 is a cross-sectional view of a main part of the first modified example in which the gripping claw unit is in a closed state. Fig. 14 is a cross-sectional view of a main part of the gripping claw unit showing a second modified example of the gripping claw unit. Fig. 15 is a cross-sectional view of a main part of the gripping claw unit in a closed state. Fig. 16 is a perspective view of a gripping device according to a sixth embodiment of the present invention. Fig. 17 is a front view of the gripping device in which the gripping claw unit of the gripping device is in a closed state. Fig. 18 is a plan view of the gripping claw unit. Fig. 19 is a conceptual view of a gripping device according to a seventh embodiment of the present invention.

[0025] [First Embodiment] A gripping device according to an embodiment of the present invention will be described with reference to Figures 1 to 10. As shown in Figure 1, the gripping device 1 is connected to the tip of a work machine 2 such as a robot. The gripping device 1 grips and releases a workpiece W. Examples of the workpiece W include, but are not limited to, mechanical parts and electronic parts.

[0026] 2A, the gripping device 1 includes a gripping jaw unit (described later) 3 that operates in an opening / closing direction C1 to grip and release the workpiece W, a gripping mechanism 4, an opening / closing drive source 5 shown in FIGS. 3 and 4, a rotation drive source 6, and a connecting portion 7 that is a base-end component of the gripping device 1. The connecting portion 7 is detachably connected to the tip of an arm of a robot or the like.

[0027] 1 , the gripping mechanism 4 supports a gripping claw unit 3 including a pair of gripping claws 8, 8 so as to be movable in the opening / closing direction C1, and rotates around a rotation axis C parallel to the opening / closing direction C1. The gripping mechanism 4 includes an opening / closing mechanism 9 and a rotation mechanism 10. <Opening / Closing Mechanism> The opening / closing mechanism 9 includes linear motion elements 11, 11 that move the pair of gripping claws 8, 8 in the opening / closing direction C1, and an opening / closing mechanism housing 12. The opening / closing mechanism housing 12 is fixed to the connecting portion 7, and a main body of the opening / closing drive source 5 is connected to the opening / closing mechanism housing 12. The linear motion elements 11, 11 facing each other at a predetermined interval are movably supported on the output portion of the opening / closing drive source 5.

[0028] <Rotation Mechanism> The rotation mechanism 10 supports the gripping jaw unit 3 for rotation about the rotation axis C. The rotation mechanism 10 has a fixed-side housing part 13, an opening / closing-side housing part 14, an extension / retraction rotation mechanism 15 shown in FIG. 7, a power transmission mechanism 16 shown in FIG. 2A, and a swing rotation shaft 17. As shown in FIG. 4, the fixed-side housing part 13 is fixed to the connecting part 7 and the opening / closing mechanism housing part 12. As shown in FIG. 2A, the opening / closing-side housing part 14 is fixed to one linear motion element 11 (on the right side in FIG. 2A) of the opening / closing mechanism 9, and is linearly movable together with this linear motion element 11 in the opening / closing direction C1.

[0029] <Telescopic Rotation Mechanism> The telescopic rotation mechanism 15 is supported by the fixed housing 13 and the opening / closing mechanism housing 12, and transmits rotation of the rotation drive source 6 shown in Figures 5 to 7 to the swinging rotation shaft 17 via a power transmission mechanism 16 shown in Figure 2A (described later). Furthermore, the telescopic rotation mechanism 15 enables the swinging rotation shaft 17 to move in the opening / closing direction C1 together with the opening / closing side housing 14. As shown in Figure 7, the telescopic rotation mechanism 15 has a speed reduction mechanism 18, an input shaft 19, an output shaft 20, a sliding bearing 21, a first gear 22, and a second gear 23.

[0030] The reduction mechanism 18 has a spur gear 18a fixed to the output shaft of the rotary drive source 6 and a spur gear 18b that meshes with the spur gear 18a and is fixed to the input shaft 19, and these spur gears 18a, 18b reduce the rotation of the rotary drive source 6. A rolling bearing is provided in the telescopic rotation mechanism main body, and the input shaft 19 is rotatably supported about the rotation axis C2 by the rolling bearing. Therefore, the rotation of the rotary drive source 6 is transmitted to the input shaft 19 by the reduction mechanism 18, and the input shaft 19 is rotatably supported about the rotation axis C2 by the rolling bearing.

[0031] The output shaft 20 is supported for rotation parallel to the input shaft 19. Slide bearings 21, 21 are provided at a predetermined interval on the telescopic rotation mechanism body. The telescopic rotation mechanism 15 supports the output shaft 20 by these slide bearings 21, 21 so that the output shaft 20 can slide freely in the axial direction parallel to the opening / closing direction C1 and also support rotation. A first gear 22 is provided on the input shaft 19, and a second gear 23 is provided on the output shaft 20. The first and second gears 22, 23 are spur gears that mesh with each other.

[0032] The second gear 23 meshes with the first gear 22 to transmit the rotational force of the first gear 22 and is movable in an axial direction parallel to the opening / closing direction C1 relative to the first gear 22. One of the first and second gears 22, 23 has an axial dimension longer than the opening / closing width of the gripping mechanism 4 ( FIG. 2A ). In this example, the axial dimension L1 of the first gear 22 is set longer than the opening / closing width.

[0033] 2A , the power transmission mechanism 16 transmits the rotation of the output shaft 20 of the telescopic rotation mechanism 15 to the oscillating rotation shaft 17. The power transmission mechanism 16 includes, for example, an input gear 16A, an output gear 16B, and a gear 16C that is provided between the input and output gears 16A and 16B as a transmission element for offsetting the inter-axial distance. The input gear 16A, the gear 16C, and the output gear 16B are each a gear train made up of spur gears.

[0034] The input gear 16A, the gear 16C, and the output gear 16B are provided inside the opening / closing side housing 14. The input gear 16A is connected to one longitudinal end of the output shaft 20 of the telescopic rotation mechanism 15. The output gear 16B is rotatably supported by the opening / closing side housing 14 coaxially with the swinging rotation shaft 17. The gear 16C, which is the transmission element, meshes with the input gear 16A and the output gear 16B, and is rotatably supported by the opening / closing side housing 14. Therefore, the power transmission mechanism 16 transmits the rotation of the telescopic rotation mechanism 15 to the swinging rotation shaft 17 via the input gear 16A, gear 16C, and output gear 16B.

[0035] [Modification of the First Embodiment] As a modification of the power transmission mechanism 16, the power transmission mechanism 16 of the rotation mechanism 10 may be a combination of a pulley and a belt. Specifically, as shown in FIG. 2B , the power transmission mechanism 16 includes primary and secondary pulleys 16a and 16b and a timing belt 16c, and these components 16a, 16b, and 16c are provided inside the opening / closing housing 14. The primary pulley 16a is connected to one longitudinal end of the output shaft 20 of the telescopic rotation mechanism 15. The secondary pulley 16b is rotatably supported by the opening / closing housing 14 coaxially with the swinging rotation shaft 17. The timing belt 16c is wound around the primary pulley 16a and the secondary pulley 16b. Therefore, the power transmission mechanism 16 transmits the rotation of the telescopic rotation mechanism 15 to the swinging rotation shaft 17 via the primary pulley 16a, the timing belt 16c, and the secondary pulley 16b.

[0036] 2A , one axial end of the swingable rotation shaft 17 is rotatably supported by the open / close side housing 14. The swingable rotation shaft 17 supports one of the grip claws 8 and also rotatably supports the entire grip claw unit 3 so that it can swing about the rotation axis C. The axis center of the swingable rotation shaft 17 is concentric with the rotation axis C. A grip claw attachment / detachment member 24 that detachably supports one of the grip claws 8 of the grip claw unit 3 is provided at the other axial end of the swingable rotation shaft 17. Note that in the first embodiment, the grip claw attachment / detachment member 24 detachably supports one of the grip claws 8 of the grip claw unit 3, but since both of the grip claws 8, 8 are detachable, the grip claw unit 3 itself may be detachable.

[0037] 1 , the opening / closing drive source 5 is a drive source that drives the gripping jaw unit 3 to open and close. As the opening / closing drive source 5, for example, a parallel chuck including an air cylinder driven by compressed air is applied. Linear motion elements 11 are connected to a pair of chuck portions 5 a, which are the output portions of this parallel chuck. The opening / closing drive source 5 drives the pair of gripping jaws 8, 8 to open and close through cooperation between the linear motion elements 11 and the swing rotation shaft 17.

[0038] 2A is a drive source that rotates the gripping jaw unit 3 around the rotation axis C. The rotation drive source 6 is, for example, an electric motor, and this motor is supported by the fixed housing portion 13.

[0039] 8 , the grip claw unit 3 has a pair of grip claws 8, 8 that operate in the opening / closing direction C1, and a grip claw connection mechanism 25 that connects parts of these grip claws 8, 8. The grip claw connection mechanism 25 is formed in a substantially U-shape and has a restoring force that allows one of the grip claws 8 to elastically deform relative to the other grip claw 8. The grip claw unit 3 is a metal or resin part in which the pair of grip claws 8, 8 and the grip claw connection mechanism 25 are integrally provided.

[0040] The term "integrally provided" means that the gripping claws 8, 8 and the gripping claw connecting mechanism 25 are not formed by combining a plurality of elements but are formed as a part or the whole of a single object from a single material by, for example, forging, machining, etc. As a pair of gripping claws 8, 8 having the gripping claw connecting mechanism 25 with the restoring force, for example, general tweezers or the like can be used.

[0041] 2A , a pressing member 26 that contacts and moves away from the other grip claw 8 is provided on the linear motion elements 11, 11 at a portion facing the other grip claw 8. The grip claw 8 supported by the grip claw attachment / detachment member 24 is referred to as one grip claw 8, and the grip claw 8 that is not supported by the grip claw attachment / detachment member 24 is referred to as the "other grip claw 8." The pressing member 26 has a housing 26a and a contact ball 26b rotatably supported by the housing 26a. The housing 26a is provided at the tip of the linear motion element 11 in the extension direction.

[0042] 9 and 10 , by moving the linear moving elements 11, 11 in one opening / closing direction C1 by the opening / closing drive source 5, the contact ball 26b of the press-down member 26 abuts against the other gripping claw 8 against the restoring force, bringing the pair of gripping claws 8, 8 into a closed state. As shown in FIGS. 1 and 2A , by moving the linear moving elements 11, 11 in the other opening / closing direction C1 by the opening / closing drive source 5, the contact ball 26b is separated from the other gripping claw 8, and the pair of gripping claws 8, 8 are brought into an open state by the restoring force. In this way, the opening / closing drive source 5 can drive the linear moving elements 11, 11 and the swing rotation shaft 17 to cooperate with each other to open and close the pair of gripping claws 8, 8.

[0043] <Operation and Effect> With the gripping device 1 described above, the gripping jaw unit 3 can be oscillated and rotated while the workpiece W is gripped by the pair of gripping jaws 8, 8 shown in Fig. 2A. Therefore, the workpiece W can be oscillated and rotated without operating the work machine to which the gripping device 1 is connected. Because the objects of rotation are mainly the workpiece W and the gripping jaws 8, 8, the weight and moment of inertia of the objects of rotation are reduced. As a result, high-speed rotation of the work machine is possible.

[0044] The swing rotation shaft 17 supports one of the gripping claws 8 and rotatably supports the entire gripping claw unit 3, and the gripping claw unit 3 is rotationally driven by the rotation drive source 6. The pair of gripping claws 8, 8 are driven to open and close by the opening / closing drive source 5 (FIG. 1) through cooperation between the linear motion elements 11, 11 and the swing rotation shaft 17. That is, by moving the linear motion elements 11, 11 in one opening / closing direction C1 by the opening / closing drive source 5 (FIG. 1), the press-down member 26 abuts against the other gripping claw 8 against the restoring force, bringing the pair of gripping claws 8, 8 into a closed state. By moving the linear motion elements 11, 11 in the other opening / closing direction C1 by the opening / closing drive source 5, the pair of gripping claws 8, 8 are brought into an open state by the restoring force.

[0045] In this way, the pair of gripping jaws 8, 8 are driven to open and close by the opening / closing drive source 5 (FIG. 1) through the cooperation of the linear motion elements 11, 11 and the swing rotation shaft 17. Therefore, unlike the conventional structure described above, there is no need to provide a mechanism for distributing rotational power from one drive source to both gripping jaws, or a drive source for simultaneously rotating independent mechanisms, and the entire gripping device can be made simpler than the conventional structure. Therefore, the gripping device 1 can be made lighter and more compact than the conventional structure.

[0046] For example, ordinary tweezers can be retrofitted as a pair of gripping claws 8, 8 having the gripping claw connecting mechanism 25 with the restoring force. This allows the approach angle to the workpiece W, for example, during bulk picking, to be changed using only the tip of the gripping device 1, making it possible to avoid interference between the robot and the gripping device 1 in an extremely small space. Furthermore, when tweezers are retrofitted, the manufacturing cost of the gripping device 1 can be reduced compared to designing a new dedicated gripping claw unit 3.

[0047] The gripping mechanism 4 includes a rotation mechanism 10 that supports the gripping jaw unit 3 to rotate about the rotation axis C. This rotation mechanism 10 transmits the rotation of the rotation drive source 6 to the swinging rotation shaft 17 and has an extension / retraction rotation mechanism 15 that enables the swinging rotation shaft 17 to extend and retract in the opening / closing direction C1. This makes it possible to transmit rotation while the gripping jaw unit 3 extends and retracts in the opening / closing direction C1, to transmit rotation while stopped at two points before and after the extension / retraction movement, and to transmit rotation at any point during the extension / retraction movement. Because the rotation drive source 6 is a motor, the orientation of the workpiece W can be easily changed to any inclination.

[0048] The swing rotation shaft 17 is provided with a gripping jaw detachable member 24 that detachably supports one of the gripping jaws 8 of the gripping jaw unit 3. This allows the gripping jaw unit 3 to be easily replaced depending on the shape of the workpiece W, the conditions of use of the gripping device 1, etc.

[0049] 7 , the telescopic rotation mechanism 15 includes a reduction gear mechanism 18, an input shaft 19, an output shaft 20, a sliding bearing 21, a first gear 22, and a second gear 23. The second gear 23 meshes with the first gear 22 to transmit the rotational force of the first gear 22 and is movable relative to the first gear 22 in an axial direction parallel to the opening / closing direction C1. Either the first or second gear 22, 23 has an axial dimension L1 longer than the opening / closing width of the gripping mechanism 4 ( FIG. 2A ). Therefore, with a small number of parts, it is possible to reliably transmit rotational torque from the input shaft 19 to the output shaft 20 and to move the output shaft 20 in the axial direction, which is the telescopic direction.

[0050] The telescopic rotation mechanism 15 has sliding bearings 21, 21 that support the output shaft 20 so that it can slide axially, and therefore has a simple structure that can maintain the rotation of the output shaft 20 while allowing the output shaft 20 to slide axially. Furthermore, the output shaft 20 is less likely to wear than in a structure without a sliding bearing, which improves the durability of the telescopic rotation mechanism 15. Because the first and second gears 22, 23 are spur gears, the rotation speed of the telescopic rotation mechanism 15 and the distance between the input and output shafts 19, 20 can be adjusted by changing the diameter and number of teeth of the spur gears. This increases the degree of freedom in the capacity, arrangement, etc. of the rotation drive source 6.

[0051] 2A , the gripping mechanism 4 has a detachable connecting part 7 at the tip of the work machine 2. This makes it easy to replace the opening / closing mechanism 9 with one having a different opening / closing stroke, for example, depending on the application of the work machine 2, the shape of the workpiece W, etc., thereby reducing the amount of work required.

[0052] <Regarding Other Embodiments> In the following description, parts corresponding to matters previously described in each embodiment are assigned the same reference numerals, and duplicated description will be omitted. When only part of the configuration is described, the other parts of the configuration are the same as those in the previously described embodiment unless otherwise specified. The same configuration produces the same effects. It is possible to combine not only the parts specifically described in each embodiment, but also parts of the embodiments together, provided that there is no particular problem with the combination.

[0053] 11 to 14] <Gripping Claw Unit Hinge Structure 1> As shown in Figures 11 and 12, a gripping claw unit 3A has a pair of gripping claws 8, 8, a hinge-like gripping claw coupling mechanism 25, and a passive rotation shaft 27 that rotatably supports the other gripping claw 8 on the gripping mechanism 4. As shown in Figure 12, one gripping claw 8 is rotatably supported on the oscillating rotation shaft 17, and the other gripping claw 8 is coupled to the linear motion element 11 via the passive rotation shaft 27. The passive rotation shaft 27 and the oscillating rotation shaft 17 are arranged coaxially.

[0054] As shown in Figure 13, each gripping jaw 8 has a jaw 8a and a jaw holder 8b that detachably holds the jaw 8a with a screw 28 or the like. The jaw 8a can be easily replaced with respect to the jaw holder 8b depending on the shape of the workpiece, the conditions of use of the gripping device, etc. In this way, the shape of the tip of the gripping jaw can be easily changed.

[0055] The hinged grip claw coupling mechanism 25, swing rotation shaft 17, and passive rotation shaft 27 in Fig. 12 allow the pair of grip claws 8, 8 to move parallel to each other but not twist, as shown in Fig. 14. When one grip claw 8 is rotated about the swing rotation shaft 17, the other grip claw 8 rotates about the passive rotation shaft 27 in synchronization with the first grip claw 8. In order to move the pair of grip claws 8, 8 parallel to each other, the hinged grip claw coupling mechanism 25 requires three joints, as shown in Fig. 13. Furthermore, the grip claw coupling mechanism 25 is located within the plane in which the grip claws 8, 8 are to be held.

[0056] 14, the pair of gripping claws 8, 8 are each rotatably supported by the gripping mechanism 4, which increases the rigidity of the gripping claw unit 3A and prevents undesired tilting of the gripping claws 8, 8, misalignment of the open / closed positions, etc. This makes it possible to further improve the positioning accuracy of the gripping device 1. Other effects similar to those of the above-described embodiment are also achieved.

[0057] 15 to 16] <Gripping claw unit hinge structure 2> As shown in Fig. 15, a gripping claw unit 3B may have a pair of gripping claws 8, 8, a hinge-like gripping claw coupling mechanism 25, and a passive rotation shaft 27 that rotatably supports the other gripping claw 8 on the gripping mechanism 4. As shown in Fig. 16, the gripping claw coupling mechanism 25 has hinge bodies 25a, 25a and rotation shafts 25b, 25b, 25c.

[0058] The claw holder 8b of each gripping claw 8 is provided with a rotation shaft 25b that is a rotation support shaft for the hinge body 25a. The base end of each hinge body 25a is rotatably supported by the claw holder 8b via the rotation shaft 25b, and the tip end of each hinge body 25a is rotatably supported relative to each other via the rotation shaft 25c. The rotation shafts 25b, 25b, and 25c are parallel to the plane PL on which the gripping claw 8 is to be held and to the longitudinal direction C3 of the claw holder 8b. Furthermore, each hinge body 25a is arranged on a plane inclined with respect to the plane PL.

[0059] With the gripping claw unit 3B equipped with the gripping claw connecting mechanism 25, when the gripping claws 8, 8 are opened or closed, most of the hinge bodies 25a, 25a extend outward beyond the claw holder 8b, etc., making them less likely to interfere with the claws 8a and gripping mechanism 4 shown in Fig. 15. With the gripping claw unit 3B equipped with this hinge structure, the gripping claw connecting mechanism 25 can be easily positioned even if the opening and closing width of the gripping mechanism 4 is small. Furthermore, because the pair of gripping claws 8, 8 are each rotatably supported by the gripping mechanism 4, the rigidity of the gripping claw unit 3B can be increased, making it possible to further improve the positioning accuracy of the gripping device 1. Other effects similar to those of the first embodiment are achieved.

[0060] [Fourth Embodiment: FIGS. 17 to 20] <Gripping Claw Slide Structure 1> As shown in FIG. 17 , a gripping claw unit 3C includes a pair of gripping claws 8, 8, a gripping claw coupling mechanism 25A that connects the gripping claws 8, 8 so that they can slide in the opening / closing direction C1, and a passive rotation shaft 27 that rotatably supports the other gripping claw 8 on the gripping mechanism 4. As shown in FIG. 18 , the gripping claw coupling mechanism 25A includes multiple (two in this example) rod-shaped members 29 that extend parallel to the opening / closing direction C1. These rod-shaped members 29, 29 are arranged in parallel at a predetermined interval. As shown in FIG. 19 , the rod-shaped members 29, 29 are, for example, common parts and have the shape of a round shaft with a circular cross section.

[0061] Each rod-shaped member 29 is provided at both longitudinal ends with a retaining member 30, such as a snap ring, to prevent the gripping claw 8 from falling off. A sliding bearing 31 is fitted and fixed in the hole of each gripping claw 8 through which the rod-shaped member 29 passes, to facilitate sliding of the gripping claw 8. As shown in FIGS. 17 and 20 , the gripping claw unit 3C opens and closes in accordance with the opening and closing of the opening / closing mechanism 9. The gripping claw unit 3C may also omit the passive rotation shaft 27. If the passive rotation shaft 27 is omitted, a restoring element, such as a compression coil spring, is provided to open the gripping claw unit 3C when the opening / closing mechanism 9 opens. When the gripping claw unit 3C includes the restoring element, one of the linear motion elements 11 (left side of FIG. 17 ) only needs to press down on the other gripping claw 8, as with the gripping claw unit 3 of the first embodiment ( FIG. 1 ).

[0062] According to the gripping claw unit 3C, two rod-shaped members 29 are inserted through a pair of gripping claws 8, 8, which can prevent twisting of the gripping claws 8, 8. This can further improve the positioning accuracy of the gripping device 1. Other effects similar to those of the first embodiment can be achieved.

[0063] 21 to 23] <Gripping claw sliding structure 2> As shown in Fig. 21 , a gripping claw unit 3D has a pair of gripping claws 8, 8 and a gripping claw coupling mechanism 25B that connects the gripping claws 8, 8 so that they can slide in the opening / closing direction C1. As shown in Fig. 22 , this gripping claw coupling mechanism 25B connects the pair of gripping claws 8, 8 so that they can slide but cannot rotate along the swinging rotation shaft 17. The swinging rotation shaft 17 in this example supports both gripping claws 8, 8.

[0064] In this embodiment, as shown in Figure 23, a portion of the outer circumferential surface of the swingable rotation shaft 17 in the longitudinal direction along which the gripping claws 8, 8 slide is formed as a polyhedron (in this example, an octahedron) 17a, or a key 32 is provided on the portion in the longitudinal direction. This prevents the gripping claws 8, 8 from rotating relative to the swingable rotation shaft 17. According to this embodiment, the gripping claw unit 3D (Figure 21) itself can be made more compact than in the fourth embodiment. This makes it possible to more reliably avoid interference with gripping devices in a very small space. Other effects similar to those of the first embodiment are achieved.

[0065] [Modification of the Fifth Embodiment] <Rotation Stopper Modification: FIGS. 24-25> In the example shown in FIG. 24, a secondary pulley 16b and one of the gripping claws 8 are fixed to one end of the oscillating rotation shaft 17 and rotatably connected to one of the linear motion elements 11. A bearing may be provided at this connection as a rotational resistance reduction member 31A. The other gripping claw 8A is connected to the oscillating rotation shaft 17 so as to be movable in the axial direction but not rotatable. A ball guide, linear guide, slider, or the like may be provided at this connection as a sliding resistance reduction member 31AA. The other end of the oscillating rotation shaft 17 is connected to the other linear motion element 11A so as to be movable in the axial direction and rotatable. A sliding bearing or ball bushing may be provided at this connection as a member 31 for reducing rotational and sliding resistance. This modification provides substantially the same effects as the fifth embodiment. Furthermore, the gripping claw slide structure can be operated more smoothly than in the fifth embodiment, resulting in higher precision and less backlash in the gripping claw unit. This makes it possible to increase the rigidity of the gripping jaw unit and extend the life of the gripping jaw unit. In this way, the gripping jaw unit can be made highly accurate, highly rigid, and have a long life.

[0066] [Modification of the Fifth Embodiment] <Cantilever Spring Structure: FIGS. 26-27> As shown in FIG. 26, one gripping claw 8 is integrally provided at the longitudinal middle of the oscillating rotation shaft 17, and as shown in FIG. 27, the other gripping claw 8 is connected to the oscillating rotation shaft 17 so as to be slidable but non-rotatable. Furthermore, as shown in FIG. 26, a restoring element 33 such as a compression coil spring is provided between the pair of gripping claws 8, 8 on the outer periphery of the oscillating rotation shaft 17. The oscillating rotation shaft 17 is also rotatably supported by a cantilever on one of the linear motion elements 11 (the right side of FIG. 26). This cantilever spring structure provides higher rigidity than the aforementioned rotation stopper modification and the first embodiment, and allows for a reduction in the number of parts, such as the pressing member, resulting in a more compact design. Other effects are substantially the same as those of the fifth embodiment.

[0067] [Sixth Embodiment: Figures 28 to 30] <Link Mechanism> As shown in Figures 28 and 29, a gripping claw unit 3E has a pair of gripping claws 8, 8 and a gripping claw coupling mechanism 25C consisting of a link mechanism 34 that couples the gripping claws 8, 8. As shown in Figure 30, the link mechanism 34 restricts the pair of gripping claws 8, 8 to move while maintaining parallelism on a plane. With a gripping claw unit 3E equipped with the gripping claw coupling mechanism 25C, when the gripping claws 8, 8 are opened or closed, most of the link mechanism 34 is positioned to the side of the claw holder 8b, etc., so the gripping claw coupling mechanism 25C can be easily positioned even if the opening and closing width of the gripping mechanism is small. Other advantageous effects are similar to those of the third embodiment.

[0068] [Seventh embodiment: Fig. 31] <Structure with direct mounting of rotational drive source and linear motion element> As shown in Fig. 31 , a rotational drive source 6 may be directly attached to one of the linear motion elements 11, 11. In this case, the rotational axis of the rotational drive source 6 is coaxially connected to the oscillating rotational axis 17, or the rotational axis also serves as the oscillating rotational axis 17. Therefore, it is possible to rotate the gripping jaw unit 3 directly via the rotational axis of the rotational drive source 6. With this gripping device, it is possible to omit the power transmission mechanism 16 (Fig. 2A) and the like, thereby achieving even lighter weight and more compactness than conventional structures.

[0069] The opening / closing drive source 5 is not limited to the air cylinder, and may be, for example, an electric cylinder, an electric motor, or a hydraulic cylinder such as a hydraulic cylinder. The rotation drive source 6 may be a structure using pneumatic pressure, such as an air cylinder, or a structure using hydraulic pressure, such as a hydraulic actuator. The power transmission mechanism 16 in FIG. 2A may be a structure including drive and driven sprockets and a drive chain wound around these sprockets. The pair of gripping claws 8, 8 (8A) may be closed by moving the tips of the pair of gripping claws 8, 8 (8A) away from each other, and may be opened by moving the tips of the pair of gripping claws 8, 8 (8A) closer to each other.

[0070] A constant velocity joint (not shown) may be used as the transmission element of the telescopic rotation mechanism 15. Specifically, as a constant velocity joint, one transmission element is a cylindrical member having a plurality of guide grooves, and the other transmission element is a shaft-shaped member, with rolling elements circumferentially evenly spaced between the cylindrical member and the shaft-shaped member. The constant velocity joint further includes a cage that prevents the rolling elements from falling off or colliding with each other.

[0071] The gripping device 1 can be attached to an output unit such as a linear actuator. The gripping device 1 can also be installed on a fixed object such as a frame and used in combination with other work machines.

[0072] As described above, the preferred embodiment has been described with reference to the drawings, but various additions, modifications, and deletions can be made without departing from the spirit of the present invention. Therefore, such additions, modifications, and deletions are also included in the scope of the present invention.

[0073] DESCRIPTION OF SYMBOLS 1...Gripping device 2...Work machine 3...Gripping claw unit 4...Gripping mechanism 5...Opening / closing drive source 6...Rotation drive source 7...Connecting portion 8, 8A...Gripping claw 9...Opening / closing mechanism 10...Rotation mechanism 11, 11A...Linear motion element 12...Opening / closing mechanism housing portion 13...Fixed side housing portion 14...Opening / closing side housing portion 15...Telescopic rotation mechanism 16...Power transmission mechanism 17...Oscillating rotation shaft 18...Reduction mechanism 18a, 18b...Spur gear 19...Input shaft 20...Output shaft 21...Sliding bearing 22...First gear 23...Second gear 24...Gripping claw attachment / detachment member 25-25C...Gripping claw coupling mechanism 26...Pressing member 27...Passive rotation shaft W...Work

Claims

1. A gripping device comprising: a gripping jaw unit that operates in an opening and closing direction to grip and release a workpiece; a gripping mechanism that supports the gripping jaw unit so that it can operate in the opening and closing direction and rotates around a rotation axis parallel to the opening and closing direction; an opening and closing drive source that drives the gripping jaw unit to open and close; and a rotation drive source that drives the gripping jaw unit to rotate around the rotation axis, wherein the gripping jaw unit has a pair of gripping jaws and a gripping jaw connection mechanism that connects parts of the gripping jaws, and the gripping mechanism includes: an oscillating rotation shaft that supports either one or both of the gripping jaws and rotatably supports the entire gripping jaw unit so that it can oscillate around the rotation axis, and an opening and closing mechanism that includes a linear motion element that allows the pair of gripping jaws to move freely in the opening and closing direction, and wherein the linear motion element and the oscillating rotation shaft work together to drive the pair of gripping jaws to open and close by the opening and closing drive source.

2. In the gripping device described in claim 1, the gripping mechanism includes a rotation mechanism that supports the gripping claw unit for rotation around the rotation axis, and this rotation mechanism transmits the rotation of the rotation drive source to the oscillating rotation shaft and has an extension and contraction rotation mechanism that allows the oscillating rotation shaft to move in the opening and closing direction.

3. A gripping device according to claim 1 or 2, wherein the rotation drive source is a motor.

4. A gripping device according to claim 1 or 2, wherein the oscillating rotation shaft is provided with a gripping claw attachment / detachment member that detachably supports one of the gripping claws of the gripping claw unit.

5. A gripping device as claimed in claim 4, wherein the gripping claw connection mechanism has a restoring force that allows one of the gripping claws to elastically deform relative to the other gripping claw, and a pressing member that abuts against and moves away from the other gripping claw is provided on the linear moving element at a portion facing the other gripping claw, and the opening / closing drive source moves the linear moving element in one opening / closing direction, causing the pressing member to abut against the other gripping claw against the restoring force, thereby placing the pair of gripping claws in a closed state, and the opening / closing drive source moves the linear moving element in the other opening / closing direction, thereby placing the pair of gripping claws in an open state due to the restoring force.

6. A gripping device according to claim 1 or 2, wherein the gripping claw unit has a passive rotation shaft that rotatably supports the other gripping claw on the gripping mechanism.

7. A gripping device as described in claim 2, wherein the telescopic rotation mechanism comprises an input shaft to which the rotation of the rotation drive source is transmitted and which is supported for rotation around the rotation axis, an output shaft which is supported for rotation parallel to the input shaft, a first gear provided on the input shaft, and a second gear provided on the output shaft which meshes with the first gear, to which the rotational force of the first gear is transmitted and which is movable in an axial direction parallel to the opening / closing direction relative to the first gear, wherein either the first or second gear has an axial dimension longer than the opening / closing width of the gripping mechanism.

8. A gripping device according to claim 7, wherein the telescopic rotation mechanism has a sliding bearing that supports the output shaft so that it can slide freely in the axial direction.

9. A gripping device according to claim 7, wherein the transmission elements of the rotation mechanism are pulleys and a belt.

10. A gripping device according to claim 7, wherein the transmission element of the rotation mechanism is a spur gear.

11. A gripping device according to claim 1 or 2, wherein the gripping mechanism has a detachable connection part at the tip of the work machine.

Images