Clamping Device

Abstract

The present invention provides a clamping device that can securely grip an object. [Solution] A base 20 having multiple arms 25, 26, 27 extending radially is connected to a mounting unit 10 attached to the tip of a robot arm. Each arm is provided with moving members 31, 32, 33 that move synchronously in the radial direction by a drive unit 40, and a claw member 50 is attached to the tip of each moving member. When the drive unit 40 is operated, the multiple claw members 50 move simultaneously toward the center and grip the flange of the container. The claw member 50 has an abutment surface that abuts the outer periphery of the flange and a support portion that engages with the underside of the flange and supports it from below. This securely holds the object by clamping it from both the radial direction and below, preventing it from falling during transport.

Description

[Technical Field]

[0001] The present invention relates to a clamping device that is attached to the tip of a robot arm. [Background technology]

[0002] Conventionally, there has been a clamping device that is attached to the tip of a robot arm and grips an object, as shown in Patent Document 1. The gripping device shown in Patent Document 1 has multiple fingers rotatably attached to a base, as shown in Fig. 12 of Patent Document 1, with joints formed in the middle of these fingers, and the multiple fingers rotate relative to the base, while the fingers on the tip side of the joint rotate, thereby gripping and releasing an object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-51575 A Summary of the Invention [Problem to be solved by the invention]

[0004] The clamping device shown in Patent Document 1 has a configuration in which multiple fingers rotate relative to a base, and the fingers at the tip of the joint rotate to grasp an object, so the clamping device's gripping force on the object is weak, and there is a risk that the object will fall during transport.

[0005] An object of the present invention is to provide a clamping device that can securely grip an object. [Means for solving the problem]

[0006] In order to achieve the above object, the clamping device according to the invention described in claim 1 is: a mounting portion (10) that is attached to the tip of the robot arm; a base (20) connected to the mounting portion and having a plurality of arms (25, 26, 27) extending radially from the center of the mounting portion; a plurality of movable members (31 to 33) attached to the arm portion so as to be movable in a radial direction from the center of the attachment portion; a drive unit (40) that simultaneously moves the plurality of moving members in the radial direction; a claw member (50) provided on the moving member and protruding toward the center of the base; death, The claw member is The device further includes a fall prevention mechanism (80) for preventing the object from falling, The fall prevention mechanism includes: a swing unit (80a) including a first member (81) swingably supported by the claw member, a second member (82) connected to an upper end of the first member and extending toward the center of the base, a first stopper member (83) attached to a lower end of the first member on the center side of the base, and a second stopper member (84) attached to the lower surface of the tip of the second member (82); a biasing member (86) that constantly biases the swing unit so that the swing unit swings toward an initial position in which the first stopper member protrudes toward the center of the base and the second stopper member is retracted upward, When the claw members grip the object, the first stopper member comes into contact with the outer periphery of the object, causing the swing unit located at the initial position to swing against the biasing force of the biasing member, and the first stopper member retreats outward relative to the center of the base, while the second stopper member swings downward to a gripping position, In the gripping position, the second stopper member is configured to be disposed opposite to an upper surface of an outer circumferential edge of the object. It is characterized by:

[0007] With this, when the multiple claw members grip an object, they simultaneously move radially toward the center, allowing the multiple claw members to grip the outer periphery of the object, thereby providing a clamping device that can reliably grip an object. Furthermore, when the swinging unit is in the gripping position, the second stopper member waits facing the upper surface of the flange portion of the object, so that if the object tilts during transport, the second stopper member receives the flange portion to prevent the tilt and stabilize the transport posture.

[0008] In addition, The object (D) to be gripped by the plurality of claw members has a flange portion (Da) formed on its outer periphery, The claw member (50) is a claw member base (50a) fixed to the moving member (31-33); a pair of engaging portions (50b) provided on both sides of the base of the claw member in the circumferential direction and engaging with the flange portion, The pair of engaging portions are spaced apart in the horizontal direction. is preferred.

[0009] With this, one claw member supports the flange portion of the object at two points, so the gripping point is stable and tilting or shaking of the object during transport can be suppressed.

[0010] In addition, The engagement portion is an abutment surface (50d) that abuts against the outer periphery of the flange portion of the object; a support portion (50c) extending radially from the lower end of the abutment surface toward the center and abutting against the lower surface of the flange portion; Having is preferred.

[0011] This allows the claw members to securely hold the flange portion of the object by clamping it from the radially outer side and from below, so that even heavy objects can be lifted stably without slipping.

[0012] In addition, the plurality of arms include a first arm, a second arm, and a third arm, The angle formed between the second arm and the third arm is set to be larger than the angle formed between the first arm and the second arm and the angle formed between the first arm and the third arm. thing is preferred.

[0013] This ensures a larger space between the second and third arms than between the other arms. When gripping one of multiple objects arranged closely on a pallet, this larger space faces the adjacent object, preventing the jaw members from coming into contact with the adjacent object. As a result, a single clamping device can efficiently and safely handle objects arranged in a variety of patterns.

[0016] Claim 2 The invention described in claim 1 In the invention described in The fall prevention mechanism is characterized by further comprising a limit switch (88) that detects whether the swing unit is positioned at the initial position or the gripping position.

[0017] This allows the activation of the fall prevention mechanism to be electrically detected and the robot's operation to be brought to an emergency halt, effectively preventing secondary damage caused by the object falling.

[0018] Claim 3 The invention described in claim 1 In the invention described in The biasing member is a torsion spring.

[0019] This allows a stable and highly reliable biasing force to be applied to the swing unit.

[0020] Claim 4 The invention described in claim 3 In the invention described in The swing unit further comprises a plunger (85); The torsion spring biases the swing unit by contacting a ball (85b) provided on the plunger.

[0021] This reduces friction at the contact points when the swing unit is in operation, as the torsion spring contacts the ball of the plunger to transmit force, resulting in smoother and more reliable biasing and improved operational accuracy of the entire fall prevention mechanism.

[0022] Claim 5 The invention described in claim 4 In the invention described in The ball is It is characterized by being made of synthetic resin.

[0023] With this, the ball that the torsion spring contacts is made of synthetic resin, which can suppress the generation of metal powder due to friction with the mating member, making it suitable for use in clean environments where there is a concern about foreign matter contamination.

[0024] Claim 6 The invention described in claim 1 In the invention described in The first stopper member and the second stopper member are characterized by being made of an elastic material.

[0025] According to this, since the first stopper member and the second stopper member are made of an elastic material, the impact when the first stopper member and the second stopper member come into contact with the object can be mitigated, and scratches on the surface of the object can be prevented.

[0026] Claim 7 The invention described in claim 2 In the invention described in The limit switch a main body portion (88a) fixed to the base of the claw member; an arm (88b) supported swingably on the main body; a roller (88c) rotatably attached to the tip of the arm and in contact with the swing unit; The swing unit is configured to press the roller, causing the arm to swing and activating a switch mechanism within the main body.

[0027] According to this, by equipping the limit switch with a roller at the end of its arm, contact with the swing unit changes from sliding contact to rolling contact, significantly reducing wear. As a result, the risk of contamination caused by metal powder generated by wear is reduced, making it suitable for use in clean environments. Furthermore, the reduction in sliding resistance makes it possible to achieve both smooth and highly reliable detection operation and long-term durability of the device.

[0028] Claim 8 The invention described in claim 7 In the invention described in The swing unit further includes an abutment member (87) made of synthetic resin, The roller is in contact with the contacted member.

[0029] This means that the contact member that comes into contact with the limit switch roller is made of synthetic resin, which prevents the generation of metal powder due to wear caused by the sliding of the two. As a result, the device can be used in clean environments where there is a risk of foreign matter being mixed in, and the reliability of the device can be improved.

[0030] In addition, The apparatus further includes an overclamping suppression mechanism (70) that restricts the movement stroke of the moving member, The overclamp suppression mechanism includes: a mounting member (71) fixed to the base; a contact member (73) provided on the mounting member and contacting the contact surface (31b to 33b) formed on the moving member; is preferred.

[0031] According to this, the movement stroke of the moving member is physically restricted, so that excessive tightening of the claw member onto the object is suppressed, and deformation or damage to the object can be suppressed.

[0032] In addition, The overclamping suppression mechanism further includes a screw member (72) that is threadedly engaged with the mounting member, The abutting member is fixed to the tip of the screw member. is preferred.

[0033] With this, since the abutment member is fixed to the tip of the screw member, the radial position of the abutment member can be precisely adjusted by simply rotating the screw member, making it possible to set an optimal tightening stroke depending on the type and size of the target object.

[0034] In addition, The contact member is made of an elastic material. is preferred.

[0035] According to this, since the contact member is made of an elastic material, the impact when the moving member contacts it is mitigated, and the generation of operating noise can be suppressed. Furthermore, since the generation of wear powder due to contact with the metal moving member is suppressed, it can be used in a clean environment where there is a concern about the intrusion of foreign matter. Furthermore, suppressing wear at the contact portion makes it possible to improve the durability of the entire device.

[0036] Note that the symbols in parentheses for each means described in this column and in the claims are merely examples showing the correspondence with the specific means described in the embodiments described below, and do not affect the scope of rights of the claims. [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a side view of a container moving device equipped with a clamping device according to an embodiment of the present invention. [Figure 2] 1 is a perspective view of a clamping device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a top view of the clamping device of the embodiment of the present invention. [Figure 4] 1 is a front view of a clamping device according to an embodiment of the present invention. [Figure 5] 1 is a side view of a clamping device according to an embodiment of the present invention. [Figure 6] FIG. 2 is a bottom view of the clamping device according to the embodiment of the present invention. [Figure 7] FIG. 6 is a detailed partial cross-sectional view of part A in FIG. 5. [Figure 8] FIG. 7 is a bottom view showing the main part of FIG. 6. [Figure 9] FIG. 10 is a detailed view showing a mechanism for preventing the claw members from falling. [Figure 10] An explanatory diagram showing the operation of the fall prevention mechanism in stages, where (A) is before gripping, (B) is during gripping, (C) is the normal lifting state, and (D) is the tilt suppression state. [Figure 11] FIG. 10 is a side view of the clamping device gripping the container. [Figure 12]4 is a cross-sectional view taken along the line BB in FIG. 3, showing a cross-sectional view of an engagement portion, where (A) shows a state before clamping and (B) shows a state after clamping. [Figure 13] This is a layout diagram showing three or four containers arranged on a pallet. DETAILED DESCRIPTION OF THE INVENTION

[0038] (Gripped object) First, a description will be given of an object to be gripped by the clamping device 100 of this embodiment. As shown in Figures 9, 10, and 11, the object to be gripped is a cylindrical resin container (object) D (hereinafter also referred to as a resin drum) with a bottom and an opening on the top surface covered with a lid D1.

[0039] As shown in FIG. 9, the container D has a flange portion Da that protrudes radially outward around the entire periphery of its upper end. A cylindrical mating protrusion Dc protrudes upward from the inner peripheral edge of this flange portion Da so as to surround the opening of the container D. On the other hand, the lid D1 has a disk-shaped lid main body D1c that covers the opening of the container D, and an annular mating recess D1b formed on the outer periphery of the lid main body D1c and having an inverted U-shaped cross section that receives the mating protrusion Dc from above. A top surface D1a that rests on the upper surface of the flange portion Da extends radially outward from the lower end of the outer peripheral wall of this mating recess D1b. In this embodiment, the top surface of the top surface D1a is formed with a tapered surface D1d that tapers downward as it moves outward.

[0040] The mating protrusion Dc of the container D fits into the mating recess D1b of the lid D1, thereby removably attaching the lid D1 to the container D and sealing the container D. The container D also has a tapered surface Db below the flange portion Da, whose inner diameter decreases as it moves downward. The clamping device 100 is designed to intentionally provide a clearance so that the claw members 50 do not come into contact with this tapered surface Db. The clamping device 100 of this embodiment can grip the container D as a whole with the lid D1 in place by gripping the flange portion Da with the claw members 50.

[0041] (Overall configuration of the robot device) The overall configuration of a robot device 500 to which a clamping device 100 according to one embodiment of the present invention is attached will be described below with reference to FIG. 1. As shown in FIG. 1, the robot device 500 is a vertical articulated robot installed on a floor 990 or the like of a factory or the like. This robot, together with the clamping device 100, is used for palletizing and depalletizing operations, such as loading and unloading containers D onto and from a pallet P (see FIG. 13). As shown in FIG. 13, a plurality of containers D are placed side by side on the pallet P, and the pallet P is used for simultaneously moving the containers D within a factory or for shipping the entire pallet P. This robot device 500 is composed of a plurality of joints 501 and an arm 502 connecting these joints. A mounting portion 503 to which the clamping device 100 according to this embodiment is attached is provided at the tip of the most distal arm 502.

[0042] (Structure of clamping device) 2 to 9, the structure of the clamping device 100 of this embodiment will be described below. The clamping device 100 is mainly composed of an attachment part 10 fixed to a robot device 500 (see FIG. 1), a base part 20 connected to the attachment part 10, three movable members (a first movable member 31, a second movable member 32, and a third movable member 33) supported so as to be movable in the radial direction relative to the base part 20, claw members 50 provided at the tip of each movable member, and a drive part 40 that simultaneously drives these three movable members.

[0043] The mounting portion 10 is a portion for fixing the clamping device 100 to a mounting portion 503 (see FIG. 1) of the robot device 500. As shown in FIGS. 3 and 5, the mounting portion 10 is composed of a disk-shaped base plate 11 and a substantially cylindrical intermediate portion 12. The base plate 11 is attached to the mounting portion 503 with a plurality of bolts 13. The intermediate portion 12 is coaxially fixed to the underside of the base plate 11. A bracket 15 extending radially is attached to the underside of the base plate 11, and a camera 19 for capturing images of the downward direction is provided at the tip of the bracket 15. This camera 19 is composed of a 3D vision sensor capable of recognizing three-dimensional shapes and scans the outline of the container D, which is the object to be grasped. The three-dimensional data obtained by the scan is then compared with pre-registered reference 3D model data of the container D, and any deviations in position and orientation are calculated. The robot device 500 corrects the movement of the arms 502 in real time based on the calculated deviation, thereby constantly guiding the claw members 50 to the correct position on the container D. Furthermore, the robot device 500 may be equipped with a floating function that detects unevenness in the force applied to each claw member 50 during gripping and fine-tunes the position of the arms 502 to grip with a uniform force.

[0044] A drive unit 40 for simultaneously driving the three moving members 31 to 33 is attached to the underside of the center portion 21 of the base portion 20. As shown in FIG. 6, the drive unit 40 has three connecting members 41 arranged radially from the center. Each connecting member 41 is connected to the first moving member 31, the second moving member 32, and the third moving member 33, respectively. In this embodiment, the drive unit 40 is an actuator operated by air pressure, and synchronously moves the three connecting members 41 forward and backward in the radial direction simultaneously via an internal gear mechanism (not shown), thereby moving each moving member 31 to 33 along the extension direction of the corresponding arm portion 25 to 27. In this embodiment, the drive unit 40 is operated by air pressure, but it may also be operated by hydraulics or electricity.

[0045] A rail mounting member 35 for installing a linear guide 60 is fixed to the underside of each arm portion 25-27 with a plurality of bolts 36. As shown in FIG. 5 and other figures, this rail mounting member 35 is a frame-shaped member with a lightening structure in which window holes 35a are formed to ensure strength while reducing weight. A guide rail 61, which is a component of the linear guide 60, is attached to the underside of the rail mounting member 35 along the longitudinal direction of the arm portions 25-27. A slider 62, which is the other component of the linear guide 60, is slidably fitted into each guide rail 61. With this configuration, the slider 62 can stably move along each arm portion 25-27 while maintaining high rigidity in the radial direction.

[0046] A first moving member 31 to a third moving member 33 are attached to the lower surface of each slider 62. The first moving member 31 is provided below the first arm 25, the second moving member 32 is provided below the second arm 26, and the third moving member 33 is provided below the third arm 27. As shown in FIG. 3, the three arms 25 to 27 are not disposed at equal angles (120°) with respect to the center of the base 20, but are disposed unevenly. Specifically, the angle between the second arm 26 and the third arm 27 is set to 150°, and the angle between the first arm 25 and the second arm 26 and the angle between the first arm 25 and the third arm 27 are each set to 105°.

[0047] Such uneven arrangement is particularly effective in palletizing and depalletizing operations. In either the case where four containers D are arranged on a pallet P as shown in FIG. 13(A) or where three containers D are arranged as shown in FIG. 13(B), by appropriately rotating the clamping device 100 in the circumferential direction, interference between adjacent containers D that are not to be gripped and unused claw members 50 can be suppressed. Specifically, by orienting the widest 150° space toward the adjacent container D, the claw members 50 can approach only the target container D without coming into contact with the other containers D. This allows a single clamping device 100 to flexibly accommodate a variety of common pallet arrangements.

[0048] A claw member 50 is attached to the underside of each of the moving members 31 to 33. As shown in Figs. 9 and 11, the claw member 50 is a member that engages with and supports the flange portion Da of the container D from the radially outer side. As shown in Figs. 9 and 12, the claw member 50 has a block-shaped claw member base 50a that is fixed to the moving members 31 to 33. As shown in Figs. 6 and 8, a pair of engagement portions 50b that protrude toward the center of the clamping device 100 are formed on both circumferential sides of the lower end of the claw member base 50a at positions spaced apart in the horizontal direction.

[0049] As shown in FIGS. 9 and 12, each engaging portion 50b has an abutment surface 50d that abuts against the outer periphery of the flange portion Da of the container D, and a support portion 50c that extends radially from the lower end of the abutment surface 50d toward the center. When the moving members 31-33 move radially toward the center from the pre-clamping state shown in FIG. 12(A) to the state shown in FIG. 12(B), the abutment surface 50d abuts against the outer periphery of the flange portion Da of the container D, and the support portion 50c abuts against the lower surface of the flange portion Da to support it. Here, the abutment surface 50d is formed as an arc-shaped concave surface facing toward the center of the clamping device 100 so as to fit along the outer periphery of the flange portion Da of the cylindrical container D. This allows the engaging portion 50b to stably support the flange portion Da of the container D over a wide area, and its cross section is formed in a substantially L-shape, clamping the flange portion Da from the radial outside and below.

[0050] (Over-clamping prevention mechanism) As shown in Fig. 8 and other figures, the clamping device 100 is provided with an overclamping prevention mechanism 70. This overclamping prevention mechanism 70 is a mechanism that prevents the claw members 50 from overclamping the container D by restricting the upper limit of the movement stroke of the movable members 31 to 33, and plays a role in restricting the movable range of each claw member 50 when it moves radially inward during clamping operation. As shown in Fig. 8, the overclamping prevention mechanism 70 is made up of a mounting member 71, a screw member 72, an abutment member 73, a screw 74, a first nut 75, a second nut 76, a mounting bolt 77, and abutment surfaces 31b to 33b formed on the movable members 31 to 33, respectively.

[0051] As shown in Figures 6, 7, and 8, each of the moving members 31 to 33 is provided with abutment recesses 31a to 33a that function as part of the overclamping prevention mechanism 70. As shown in Figure 6, these abutment recesses 31a to 33a are formed on the side surfaces of the moving members 31 to 33. Flat abutment surfaces 31b to 33b are formed on the bottoms of each of the abutment recesses 31a to 33a, i.e., on surfaces perpendicular to the movement direction of each of the claw members 50. These abutment surfaces 31b to 33b are surfaces that come into direct contact with abutment members 73 of the overclamping prevention mechanism 70 that are fixed to the base 20 side.

[0052] 7 and 8, the mounting member 71 is a substantially rectangular block-shaped member with the vertical direction as the longitudinal direction, and has bolt holes formed therein through which mounting bolts 77 are inserted. The mounting member 71 is fixed by the multiple mounting bolts 77 to the underside of the rail mounting member 35, which is fixed to the underside of each of the arm portions 25 to 27.

[0053] 8 and other figures, a screw member 72, which is a fully threaded bolt (threaded bolt), is threaded with its axis along the radial direction onto the radially outer end face of the lower end of the mounting member 71. A first nut 75 is threaded onto this screw member 72, and after rotating the screw member 72 to adjust its radial position, the first nut 75 is tightened onto the end face of the mounting member 71, thereby restricting rotation of the screw member 72 and fixing its position.

[0054] A second nut 76 is threaded into the radially outer end of the screw member 72. A screw hole 72a is formed in the radially outer end of the screw member 72. An abutting member 73 is disposed at the radially outer end of the screw member 72. The abutting member 73 is generally cylindrical and made of an elastic material such as rubber or synthetic resin, which also functions as a buffer material for absorbing impact when the moving members 31 to 33 abut against it. A bolt recess 73a is formed as a recess on the radially outer end surface of the abutting member 73. The head of a screw 74 is disposed in the bolt recess 73a, and the screw 74 is threaded into a female-threaded screw hole 72a formed at the end of the screw member 72, thereby attaching the abutting member 73 to the tip (radially outer) of the screw member 72. In this way, by tapping the part (screw member 72) itself and fastening another part (screw 74), a space-saving and reliable fastening structure is realized. With this structure, by loosening the first nut 75 and rotating the screw member 72, the radial position of the abutting member 73 can be precisely adjusted.

[0055] When the drive unit 40 is actuated, the moving members 31 to 33 move inward, and when the abutment surfaces 31b to 33b hit the abutment member 73, further movement is physically stopped. This structure prevents the claw members 50 from tightening excessively (overclamping) onto the container D, thereby enabling secure gripping while preventing deformation or damage to the container D.

[0056] (Fall prevention mechanism) As shown in Fig. 9, a radially penetrating storage space 50f is formed between the pair of engaging portions 50b of the claw member base 50a. This storage space 50f is provided with a fall prevention mechanism 80 that acts as a fail-safe by physically engaging with the flange portion Da to prevent the container D from falling completely in the unlikely event that the container D becomes unstable and tilts. The fall prevention mechanism 80 is primarily composed of a swing unit 80a consisting of a first member 81, a second member 82, a first stopper member 83, a second stopper member 84, a plunger 85, and an abutted member 87, a torsion spring 86, and a limit switch 88. As will be described later, this fall prevention mechanism 80 also functions as a seating confirmation mechanism that detects whether the clamping device 100 is properly set (seated) on the container D.

[0057] The pair of first members 81 are plate-shaped members that are disposed within the storage space 50f and are swingably attached to the claw member bases 50a on both sides of the storage space 50f. Specifically, a shaft hole 81a is formed in the first member 81, and a support shaft 89 is inserted into this shaft hole 81a. This support shaft 89 is fixed to the claw member bases 50a on both sides of the storage space 50f, and the first member 81 is swingably attached to the claw member bases 50a. The second member 82 is a plate-shaped member that is attached to the upper ends of the pair of first members 81, protrudes toward the center of the clamp device 100, and extends in a direction perpendicular to the extension direction of the first members 81.

[0058] The first stopper member 83 and the second stopper member 84 are made of an elastic material such as synthetic resin or rubber. The first stopper member 83 is a block-shaped member, and is attached to the lower end of the first member 81 toward the center of the clamp device 100. The first stopper member 83 is a member that abuts against the outer peripheral edge of the flange portion Da.

[0059] The second stopper member 84 is a block-shaped member and is attached to the underside of the tip of the second member 82. The second stopper member 84 is a member that faces the top surface D1a of the lid D1 when the fall prevention mechanism 80 is in a gripping state (closed position) described below. The underside of the second stopper member 84 has a shape that corresponds to the upper surface of the top surface D1a of the lid D1 when the fall prevention mechanism 80 is in a gripping state described below. In other words, in this embodiment, the underside of the second stopper member 84 is inclined so that it is positioned upward as it moves closer to the center of the clamp device 100.

[0060] The plunger 85 is mounted in a mounting hole 81b formed at the lower end of the claw member base 50a. The plunger 85 comprises a cylindrical body 85a with a bottom and an outward opening, a ball 85b attached to the opening of the body 85a so as to be movable in the approximate axial direction, and a coil spring 85c that biases the ball 85b outward. The body 85a and ball 85b are made of synthetic resin such as polyacetal. In particular, the ball 85b, which slides and abuts against the body 85a, is made of synthetic resin, achieving smooth operation with low friction and effectively suppressing the generation of metal powder due to wear between the ball 85b and the second arm 86c of the torsion spring 86, which serves as the mating component. Therefore, the clamp device 100 is also suitable for use in clean environments where contamination of products is a concern. The plunger 85 biases the second arm 86c outward with the ball 85b at its tip. This ensures that the contact between the first stopper member 83 and the flange portion Da of the container D is maintained.

[0061] As shown in Fig. 9, the torsion spring 86 is a leaf spring formed by bending a single elastic metal plate, and functions as a torsion spring by generating a torsion moment. Specifically, the torsion spring 86 is integrally formed with a first arm portion 86a extending from a fixed end fixed to the claw member base portion 50a, a central bent portion 86b bent back toward the center from the tip (lower end) of the first arm portion, and a second arm portion 86c bent back downward from the tip of the central bent portion 86b, extending downward and having an operating end at its tip that abuts against the ball 85b of the plunger 85. With this configuration, the second arm portion 86c of the torsion spring 86 constantly generates a force that urges the first member 81 toward the initial position (counterclockwise in Fig. 9) via the plunger 85.

[0062] The contact member 87 is a plate-shaped member made of synthetic resin, and is attached to the outer surface of the first member 81 on one side.

[0063] The limit switch 88 is fixed to the outer surface of the claw member base 50a and detects the swing of the first member 81 to detect whether the clamp device 100 is seated on and gripping the container D. As shown in FIG. 9, the limit switch 88 is composed of a main body 88a that houses a switch mechanism and is fixed to the claw member base 50a, an arm 88b extending from the main body 88a, and a roller 88c rotatably attached to the tip of the arm 88b. The roller 88c abuts against the contacted member 87 and activates a switch in the main body 88a via the arm 88b in response to the swing of the first member 81. Specifically, when the first member 81 swings to the gripping position in the direction opposite to the direction of the force applied by the torsion spring 86 (clockwise in the example of FIG. 9), the contacted member 87 presses the roller 88c, which is detected by the limit switch 88. This confirms that the clamping device 100 has gripped the container D.

[0064] 2 and 9, a cover 51 is attached to the outer surface of the claw member base 50a. This cover 51 is arranged to externally cover the limit switch 88 and torsion spring 86 that constitute the fall prevention mechanism 80. As a result, the cover 51 serves to protect these internal parts from external dust and shocks due to unexpected contact.

[0065] (Fall prevention mechanism operation) Next, the operation of the fall prevention mechanism 80 will be described with reference to FIG. 10(A) shows the state immediately before the clamp device 100 grips the container D. In this state, there is no pressure from the container D, so the swing unit 80a is in its initial position due to the biasing force of the torsion spring 86, and the first stopper member 83 protrudes toward the center in the radial direction.

[0066] FIG. 10(B) shows the state in which the clamping device 100 has gripped the container D. As the claw members 50 move toward the radial center, the first stopper member 83 first abuts against the outer periphery of the flange portion Da of the container D. The swinging unit 80a then swings to the gripping position against the biasing force of the torsion spring 86. The abutted member 87 then presses the roller 88c, and the limit switch 88 detects this and outputs to the control unit of the robot device 500 a signal indicating that the clamping device 100 is properly seated on the container D and in a gripping state. Upon receiving this signal, the robot device 500 begins an operation to lift the container D. In this gripping position, the second stopper member 84 is positioned opposite the upper surface of the top surface D1a of the lid D1 adjacent to the flange portion Da of the container D.

[0067] 10(C) shows a state in which the clamping device 100 properly grips and lifts the container D. The swinging unit 80a is held in the gripping position. The second stopper member 84 is spaced a specified distance from the top surface portion D1a.

[0068] 10(D) shows a state in which the container D tilts relative to the clamping device 100 for some reason during transport, and the second stopper member 84 abuts against the top surface portion D1a, preventing further tilting of the container D. This prevents the container D from falling completely, and prevents damage to products and equipment.

[0069] (Effect of clamping device) The effects of the clamping device 100 of this embodiment will be described below. The clamping device 100 of this embodiment is composed of an attachment part 10 attached to the tip of a robot arm, a base part 20 connected to the attachment part, three movable members 31, 32, 33 supported so as to be movable radially relative to the base part, claw members 50 provided at the tip of each movable member, and a drive part 40 that drives these three movable members simultaneously.

[0070] According to this, the drive unit 40 simultaneously moves the three moving members 31, 32, 33 toward the center in the radial direction, and the multiple claw members 50 simultaneously grip the flange portion Da provided on the outer periphery of the container D. In particular, since the claw members 50 securely hold the flange portion Da by pinching it from the radial outside and from below, even a heavy container D can be stably lifted without slipping, and the risk of dropping the container D during transport can be reduced.

[0071] Furthermore, each claw member 50 has a pair of engaging portions 50b that support the flange portion Da of the container D at two locations spaced apart in the circumferential direction.

[0072] This stabilizes the gripping point, and prevents the container D from tilting or shaking during transportation.

[0073] The claw member 50 also has a contact surface 50d that contacts the outer periphery of the flange portion Da of the container D, and a support portion 50c that extends radially from the lower end of the contact surface 50d toward the center and contacts the lower surface of the flange portion Da.

[0074] According to this, the claw members 50 securely hold the flange portion Da by pinching it from the outside in the radial direction and from below, so that even a heavy container D can be lifted stably without slipping.

[0075] Also, as shown in Figure 3, the angle (150°) formed between the second arm 26 and the third arm 27 is set to be larger than the angle (105°) formed between the first arm 25 and the second arm 26 and the angle (105°) formed between the first arm 25 and the third arm 27.

[0076] This ensures a wider space between the second arm 26 and the third arm 27 than between the other arms. As shown in Fig. 13, when gripping one of multiple containers D arranged closely on a pallet P, by directing this wider space toward the adjacent container D, it is possible to prevent the claw members 50 from coming into contact with the adjacent container D. As a result, it becomes possible to efficiently and safely handle containers D arranged in various patterns with a single clamping device 100.

[0077] Each of the claw members 50 is provided with a fall prevention mechanism 80 for preventing the container D from falling.

[0078] According to this, in the unlikely event that the container D becomes unstable and tilts, the fall prevention mechanism 80 physically engages with the flange portion Da, acting as a fail-safe function to prevent the container D from completely falling. Furthermore, by detecting the operation of this mechanism with a limit switch 88, the operation of the robot can be brought to an emergency halt, effectively preventing secondary damage.

[0079] The fall prevention mechanism 80 also includes a limit switch 88 that detects whether the swing unit 80a is in the initial position or the gripping position.

[0080] This allows the activation of the fall prevention mechanism 80 to be electrically detected and the operation of the robot device 500 to be stopped immediately, thereby effectively preventing secondary damage caused by the container D falling.

[0081] The biasing member of the fall prevention mechanism 80 is a torsion spring 86 .

[0082] This allows a stable and highly reliable biasing force to be applied to the swing unit 80a.

[0083] The swing unit 80a is provided with a plunger 85, and the torsion spring 86 comes into contact with a ball 85b made of synthetic resin provided on the plunger 85, thereby biasing the swing unit 80a.

[0084] With this, the torsion spring 86 abuts against the ball 85b of the plunger 85 to transmit force, reducing friction at the contact point when the swing unit 80a is in operation. As a result, smoother and more reliable biasing is possible, improving the operating accuracy of the entire fall prevention mechanism 80. Furthermore, because the ball 85b is made of synthetic resin, the generation of metal powder due to friction with the mating member can be suppressed, making it suitable for use in clean environments where there is a concern about foreign matter being mixed in.

[0085] The first stopper member 83 and the second stopper member 84 of the fall prevention mechanism 80 are made of an elastic material.

[0086] According to this, since the first stopper member 83 and the second stopper member 84 are made of an elastic material, the impact when they come into contact with the container D is mitigated, and scratches on the surface of the container D can be prevented.

[0087] Furthermore, the limit switch 88 comprises a main body 88a fixed to the claw member base 50a, an arm 88b, and a roller 88c rotatably attached to the tip of the arm 88b, and this roller 88c abuts against an abutment member 87 made of synthetic resin and provided on the swing unit 80a.

[0088] According to this, by providing a roller 88c at the tip of the arm 88b of the limit switch 88, contact with the swing unit 80a becomes rolling contact, which significantly reduces wear. Furthermore, because the contacted member 87 that contacts the roller 88c is made of synthetic resin, it is possible to prevent the generation of metal powder due to wear caused by contact between the two. As a result, it is possible to adapt it to use in clean environments where there is a concern about foreign matter contamination, and it is possible to achieve both smooth and highly reliable detection operation and long-term durability of the device.

[0089] The swing unit 80a also includes a contact member 87 made of synthetic resin. A roller 88c of the limit switch 88 is configured to contact the contact member 87.

[0090] According to this, since the contact member 87 that contacts the roller 88c of the limit switch 88 is made of synthetic resin, it is possible to suppress the generation of metal powder due to wear caused by contact between the two. As a result, it is suitable for use in clean environments where there is a concern about foreign matter contamination, and the reliability of the device can be improved.

[0091] Furthermore, the clamp device 100 is equipped with an over-clamping prevention mechanism 70 that restricts the upper limit of the movement stroke of the movable members 31, 32, and 33. This over-clamping prevention mechanism 70 has an attachment member 71 fixed to the base 20 side, and an abutment member 73 that is provided on this attachment member 71 and abuts against abutment surfaces 31b, 32b, and 33b formed on the movable members 31, 32, and 33.

[0092] According to this, the movement stroke of the moving members 31, 32, 33 is physically restricted, so that excessive tightening of the claw members 50 onto the container D is suppressed, and deformation and damage of the container D can be suppressed.

[0093] The overclamping suppression mechanism 70 also has a screw member 72 that screws into the mounting member 71 , and an abutment member 73 is fixed to the tip of the screw member 72 .

[0094] This allows precise adjustment of the radial position of the abutting member 73 by the simple operation of rotating the screw member 72. As a result, it becomes possible to set an optimal tightening stroke according to individual differences in the type and dimensions of the container D.

[0095] Furthermore, the contact member 73 of the overclamping prevention mechanism 70 is made of an elastic material.

[0096] According to this, since the contact member 73 is made of an elastic material, the impact when the moving members 31, 32, 33 come into contact is mitigated, and the generation of operating noise can be suppressed. Furthermore, since the generation of wear powder due to contact with the metal moving members is suppressed, it can be used in a clean environment where there is a concern about the intrusion of foreign matter.

[0097] (Other embodiments) The present invention has been described above in relation to the embodiment that is considered to be the most practical and preferable at this time. However, the present invention is not limited to the embodiment disclosed in the specification of this application, and can be modified as appropriate within the scope of the claims and the gist or idea of ​​the invention that can be read from the specification as a whole. It should be understood that clamp device 100 with such modifications is also included within the technical scope of the patent right.

[0098] In the embodiment described above, the number of arms 25, 26, 27 provided on the base 20 is three, but the present invention is not limited to this, and the base 20 may have two, or four or more arms.

[0099] Furthermore, although the driving unit 40 in this embodiment is an actuator that operates by air pressure, it is not limited to this, and other types of actuators that use hydraulic pressure, an electric motor, or the like as a power source may also be used.

[0100] In the embodiment, the three arms 25, 26, and 27 are arranged at uneven angles of 150°, 105°, and 105°, but these angles can be set appropriately depending on the arrangement of the containers D on the pallet P. Alternatively, all of the arms may be arranged at equal angles.

[0101] Furthermore, in the embodiment, a 3D vision sensor is used as the camera 19 to recognize the position of the container D, but a two-dimensional camera or other distance sensor may also be used, or when handling a container D whose position is precisely determined in advance, a configuration may be adopted in which a sensor such as the camera 19 is omitted.

[0102] The object to be grasped is not limited to the cylindrical container D shown in the embodiment, but may be a rectangular container or any other object of various shapes as long as it can be grasped by the claw members 50.

[0103] The clamp device 100 may be an embodiment in which the attachment portion 10 and the base portion 20 are integrated. [Explanation of symbols]

[0104] 10 Mounting part 20 base 25 1st arm (arm) 26 Second arm (arm) 27 Third arm (arm) 31 First moving member (moving member) 32 Second moving member (moving member) 33 Third moving member (moving member) 31b Contact surface 32b Contact surface 33b Contact surface 40 Drive unit 50 Claw member 50a Claw member base 50b Engagement part 50c support part 50d Contact surface 70 Overclamp suppression mechanism 71 Mounting material 72 Screw material 73 Contact member 80 Fall prevention mechanism 80a Swing Unit 83 First stopper member 84 Second stopper member 85 Plunger 85b ball 86 Torsion spring (biasing member) 87 Contacted member 88 Limit Switch 88a Main body 88b Arm 88c Lola 100 Clamping device D Container (object) Da flange part

Claims

1. a mounting portion (10) attached to the tip of a robot arm; a base (20) connected to the mounting portion and having a plurality of arms (25, 26, 27) extending radially from the center of the mounting portion; A plurality of movable members (31 to 33) attached to the arm portion so as to be movable in a radial direction from the center of the attachment portion; a drive unit (40) that simultaneously moves the plurality of moving members in the radial direction; a claw member (50) provided on the moving member and protruding toward the center of the base, The claw member is The device further includes a fall prevention mechanism (80) for preventing the object from falling, The fall prevention mechanism includes: a swing unit (80a) comprising a first member (81) swingably supported by the claw member, a second member (82) connected to an upper end of the first member and extending toward the center of the base, a first stopper member (83) attached to a lower end of the first member on the center side of the base, and a second stopper member (84) attached to the lower surface of the tip of the second member (82); a biasing member (86) that constantly biases the swing unit so that the swing unit swings toward an initial position in which the first stopper member protrudes toward the center of the base and the second stopper member is retracted upward, When the claw members grip the object, the first stopper member abuts against the outer periphery of the object, causing the swing unit located at the initial position to swing against the biasing force of the biasing member, so that the first stopper member retreats outward relative to the center of the base, and the second stopper member swings downward to a gripping position, A clamping device characterized in that, in the gripping position, the second stopper member is configured to be positioned opposite an upper surface of an outer peripheral edge of the object.

2. The clamping device according to claim 1, further comprising a limit switch (88) for detecting whether the swinging unit is in the initial position or the gripping position.

3. 2. The clamping device according to claim 1, wherein the biasing member is a torsion spring.

4. The rocking unit further comprises a plunger (85); 4. The clamping device according to claim 3, wherein the torsion spring biases the swing unit by contacting a ball (85b) provided on the plunger.

5. The ball is 5. The clamping device according to claim 4, which is made of synthetic resin.

6. 2. The clamp device according to claim 1, wherein the first stopper member and the second stopper member are made of an elastic material.

7. The limit switch a main body portion (88a) fixed to the base of the claw member; an arm (88b) supported swingably on the main body; a roller (88c) rotatably attached to the tip of the arm and in contact with the swing unit; 3. The clamp device according to claim 2, wherein the arm swings when the swing unit presses the roller, thereby activating a switch mechanism within the main body.

8. The swing unit further includes an abutment member (87) made of synthetic resin, 8. The clamping device according to claim 7, wherein the roller abuts against the abutted member.

Images