Gripping device

Abstract

To suppress positional deviation of tip parts of a plurality of fingers.SOLUTION: A gripping device includes a moving mechanism for bringing a plurality of fingers close to each other and separating the plurality of fingers from each other, the moving mechanism includes at least a rail attachment unit and a plurality of rails attached to the rail attachment unit, and the plurality of rails are attached to installation surfaces constituting the same plane in the rail attachment unit.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gripping device. [Background technology]

[0002] A gripping device is known that includes a moving mechanism having a rail mounting portion, two rails attached to the rail mounting portion, running bodies attached to each of the rails, and holding portions attached to each of the running bodies and holding claw portions (fingers) (see, for example, Patent Document 1).

[0003] The rail mounting part of this gripping device had two opposing protrusions on a plane perpendicular to the vertical direction, and rails were attached to each of the protrusions. Furthermore, a movement mechanism was used to move multiple claws (fingers) closer and farther apart to grip the object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-94658 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 leaves room for improvement in terms of suppressing positional deviation of the tips of the multiple claws (multiple fingers).

[0006] The present invention has been made in view of the above, and has an object to provide a gripping device that can suppress positional deviation of the tip ends of multiple fingers. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the gripping device of the present invention comprises a moving mechanism that moves multiple fingers closer to and apart, and the moving mechanism comprises at least a rail mounting portion and multiple rails attached to the rail mounting portion, and the multiple rails are each attached to an installation surface that forms the same plane on the rail mounting portion.

[0008] According to one aspect of the gripping device of the present invention, it is possible to suppress positional deviation of the tip portions of the multiple fingers. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a gripping device according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of the gripping device shown in FIG. 1 with a part cut away. [Figure 3] FIG. 3 is an exploded view of the gripping device shown in FIG. [Figure 4] 4 is an exploded view of the movement mechanism of the gripping device shown in FIG. 1 with a part cut away. [Figure 5] 5 is a perspective view of a rail and a traveling body with a part broken away, which are provided in the movement mechanism shown in FIG. [Figure 6] 6 is a perspective view of a finger included in the moving mechanism shown in FIG. [Figure 7] 7 is a perspective view of a rail and a traveling body included in the movement mechanism shown in FIG. 3, with a part cut away. [Figure 8] 8 is a perspective view showing the operation of placing an adjustment member (shim) between the traveling body and the holder included in the movement mechanism shown in FIG. [Figure 9] FIG. 9 is a side view showing a state in which the adjustment member is disposed between the traveling body and the holder at a position spaced apart from the first portion of the holder by the operation shown in FIG. [Figure 10] FIG. 10 is a side view showing a state in which the adjustment member is disposed between the traveling body and the holder and in a position close to the first portion of the holder. [Figure 11] FIG. 11 is a perspective view of a rail mounting portion of a gripping device according to the second embodiment. [Figure 12] FIG. 12 is a perspective view showing a holder of a gripping device according to a third embodiment. [Figure 13] FIG. 13 is a perspective view showing the assembly of the gripping device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The gripping device 1 according to the embodiment will be described below with reference to the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the dimensional relationships and ratios of elements in the drawings may differ from reality. The dimensional relationships and ratios may differ between the drawings. Furthermore, the content described in one embodiment is, in principle, applicable to other embodiments as well.

[0011] The gripping device 1 according to this embodiment shown in FIG. 1 is provided, for example, at the tip of a manipulator such as a robot, and is used in a device for gripping an object (workpiece). The gripping device 1 is mounted, for example, on a so-called six-axis articulated robot that can move the gripping device 1 in a first direction, a second direction, and a third direction. That is, the gripping device 1 according to this embodiment can move in the first direction, the second direction, and the third direction by driving the six-axis articulated robot, for example. Such a six-axis articulated robot is installed, for example, on a product assembly line or manufacturing line. The gripping device 1 may also be mounted on industrial robots such as horizontal articulated robots, parallel link robots, Cartesian robots, and collaborative robots.

[0012] FIG. 1 is a perspective view of a gripping device 1 according to a first embodiment. FIG. 2 is a perspective view of the gripping device 1 shown in FIG. 1 with a portion cut away. FIG. 3 is an exploded view of the gripping device 1 shown in FIG. 1. FIG. 4 is an exploded view of a movement mechanism 30 included in the gripping device 1 shown in FIG. 1 with a portion cut away. FIG. 5 is a perspective view of a rail 32 and a partially cutaway running body 33 included in the movement mechanism 30 shown in FIG. 3. FIG. 6 is a perspective view of a finger 35 included in the movement mechanism 30 shown in FIG. 3. In each drawing, for ease of explanation, for example, a direction parallel to the installation surface 31F and in which the rail 32 extends is defined as a first direction (X-axis direction), a direction perpendicular to the installation surface 31F is defined as a second direction (Z-axis direction), and a direction perpendicular to the first and second directions is defined as a third direction (Y-axis direction). The first direction, the second direction, and the third direction are mutually perpendicular. The first direction is the direction in which the traveling body 33 and the holder 34 move, and includes a first positive direction side and a first negative direction side. The second direction is, for example, the up-down direction, and includes an upper side, which is the second positive direction side, and a lower side, which is the second negative direction side. The third direction includes a third positive direction side and a third negative direction side. Note that in the figure, only the first positive direction side, the second positive direction side, and the third positive direction side are shown, and the first negative direction side, the second negative direction side, and the third negative direction side are omitted, but these negative directions are opposite to the positive direction side. Furthermore, as described above, since the gripping device 1 is mounted on a robot or the like, the above-mentioned directions change depending on the posture of the robot.

[0013] As shown in FIG. 1, the gripping device 1 includes a first assembly 2 and a second assembly 3 which is a movement mechanism 30.

[0014] The first assembly 2 has a support section 21 to which the movement mechanism 30 is attached, and a drive section 22 that is a drive source for the movement mechanism 30. The support section 21 has a function of attaching the gripping device 1 to a robot.

[0015] As shown in FIG. 2, the support portion 21 includes, for example, a pair of opposing portions 211a and 211b that face each other in the second direction, and a connecting portion 212 that connects the pair of opposing portions 211a and 211b.

[0016] Of the pair of opposing portions 211a, 211b, the opposing portion 211a located on one side (upper side) in the second direction is formed with a drive shaft insertion hole 211H1 for inserting the drive shaft 221a, a first bolt insertion hole 211H2 for inserting the first bolt Bo1, and a notch 211S3 (see Figure 3) for inserting the second bolt Bo2.

[0017] The drive shaft insertion hole 211H1, the first bolt insertion holes 211H2, and the notches 211S3 penetrate the opposing portion 211a in the second direction. Moreover, the opposing portion 211a according to this embodiment has one drive shaft insertion hole 211H1, four first bolt insertion holes 211H2, and four notches 211S3.

[0018] The drive shaft insertion hole 211H1 is disposed in the center of the opposing portion 211a when viewed from the second direction. On the other hand, the four first bolt insertion holes 211H2 and the four cutouts 211S3 are disposed at the four corners of the opposing portion 211a when viewed from the second direction.

[0019] As will be described later, when the facing portion 211a is placed on the motor case 222 so that the first bolt insertion holes 211H2 and the first screw holes Nu1 are aligned in the first and third directions, and the first bolts Bo1 and the first screw holes Nu1 are screwed together, the facing portion 211a is attached to the motor case 222. In other words, the portion of the facing portion 211a where the four first bolt insertion holes 211H2 are formed is the position where the motor case 222 is attached.

[0020] The first bolt insertion hole 211H2 is disposed closer to the axis 211z of the drive shaft 221a in the radial direction than the notch 211S3.

[0021] The driving unit 22 is a driving source of the movement mechanism 30. The driving unit 22 includes, for example, a motor 221, a motor case 222 that houses the motor 221, an encoder 223, and a cam 224. Note that in Fig. 3, a plurality of bearings 225 and a plurality of shafts 226 are attached to the cam 224, but the plurality of bearings 225 and the plurality of shafts 226 are components included in the second assembly 3 (movement mechanism 30).

[0022] The motor 221 is, for example, an electric drive source, and is electrically connected to a power supply (not shown). The motor 221 has a drive shaft 221a that can be rotated when power is supplied from the power supply. In other words, the gripping device 1 includes a drive unit 22 having the drive shaft 221a. When power is supplied from the power supply, the motor 221 rotates the drive shaft 221a around an axis 211z (see FIG. 3).

[0023] The motor case 222 is formed, for example, in the shape of a hollow rectangular parallelepiped using a plurality of plate materials. Furthermore, a plurality of first screw holes Nu1 are formed at one end (upper end) of the motor case 222 in the second direction. The motor case 222 is fixed to the support part 21 by fastening first bolts Bo1, the tips of which are inserted into the first bolt insertion holes 211H2 of the facing part 211a, into the first screw holes Nu1.

[0024] The encoder 223 detects the rotational position of the motor 221. The encoder 223 is disposed, for example, on the other side (lower side) in the second direction of the motor case 222. The encoder 223 may be, for example, an optical or magnetic encoder. Based on the information from the encoder 223, the position and speed of the finger 35 can be accurately controlled.

[0025] As shown in Fig. 3, the cam 224 is formed, for example, in a disk shape. The cam 224 has a through-hole 224H that penetrates the cam 224 in the second direction. The tip of the drive shaft 221a of the motor 221 is inserted into the through-hole 224H, and the cam 224 is fixed to the tip (upper end) of the drive shaft 221a. The cam 224 is formed by sintering, for example, an iron-based sintered material in a die molding process. The cam 224 also has a cam groove 224D that is recessed in the second direction from one end face 224f1 located on the second positive direction side toward the other end face 224f2 located on the second negative direction side.

[0026] A plurality of cam grooves 224D (two in this embodiment) are formed in the cam 224. Each of the cam grooves 224D extends in the circumferential direction about the axis 221z of the drive shaft 221a. When viewed from the second direction, the distance between the axis 221z and the center of each of the cam grooves 224D gradually increases toward the end 224s on one side, while the distance between the axis 221z and the center of each of the cam grooves 224D gradually decreases toward the end 224e on the other side.

[0027] A bearing 225 is inserted into each of the plurality of cam grooves 224D. The bearings 225 function as cam followers for the cams 224. A lubricant is applied to the inner wall surfaces of the cam grooves 224D.

[0028] The other end (lower end) of the shaft 226 is inserted into the bearing 225. More specifically, the other end of the shaft 226 is the other end (lower end) in the second direction, and the other end of the shaft 226 is press-fitted into the bearing 225 according to this embodiment. Note that, in this embodiment, two bearings 225 are provided at the other end (lower end) of the shaft 226 in the second direction, but the number of bearings 225 can be changed as appropriate.

[0029] Shaft 226 is formed to extend in the second direction. The end of shaft 226 on the other side (lower side) in the second direction is inserted into bearing 225 as described above. Meanwhile, the end of shaft 226 on one side (upper side) in the second direction is inserted into a hole formed in holder 34 shown in FIG. 4.

[0030] The movement mechanism 30, which is the second assembly 3, includes a rail mounting portion 31, a plurality of rails 32, a plurality of running bodies 33, a plurality of holders 34, and a plurality of fingers 35 (see FIG. 6). As described above, the movement mechanism 30, which is the second assembly 3, also includes a plurality of bearings 225 and a plurality of shafts 226.

[0031] The movement mechanism 30 moves multiple (two in this embodiment) fingers 35 close to and apart in a first direction. The movement mechanism 30 according to this embodiment grips an object (workpiece) by, for example, moving two fingers 35 close to each other in the first direction, and releases the object by moving the two fingers 35 apart.

[0032] The rail mounting portion 31 according to this embodiment is a cam case that houses the above-described cam 224 inside. The rail mounting portion 31 is made of, for example, stainless steel, and is configured in a hollow, approximately rectangular parallelepiped shape with an opening formed on the other side (lower side) in the second direction. The opening on the other side (lower side) in the second direction of the rail mounting portion 31 is closed by the above-described opposing portion 211a.

[0033] As shown in Figure 4, the rail mounting portion 31 has a main body 311 that is plate-shaped and has a rectangular shape when viewed from the second direction, and is arranged on one side (upper side) of the rail mounting portion 31 in the second direction, a frame-shaped portion 312 that is arranged on the other side (lower side) of the rail mounting portion 31 in the second direction and has a frame shape, and multiple (two in this embodiment) protruding portions 313 that protrude from the main body 311.

[0034] The main body 311 is formed with a plurality of (two in this embodiment) shaft insertion holes 311H1 through which the shafts 226 are inserted, and through holes 311H2 that are arranged between the plurality of shaft insertion holes 311H1 when viewed from the second direction. The shaft insertion holes 311H1 and the through holes 311H2 penetrate the main body 311 in the second direction.

[0035] The size of each of the shaft insertion holes 311H1 is larger than the size of each of the shafts 226 in the radial direction (shaft diameter).

[0036] The through hole 311H2 is formed, for example, in a circular shape, and is used for inspection to confirm whether the drive unit 22 including the drive shaft 221a is positioned in the correct position relative to the rail mounting portion 31 when assembling the gripping device 1.

[0037] A second screw hole Nu2 is formed in the frame-shaped portion 312 of the rail mounting portion 31. The second screw hole Nu2 is disposed on the other end side (lower end side) of the rail mounting portion 31 in the second direction. On the other hand, the holder 34 is disposed on one side (upper side) of the rail mounting portion 31 in the second direction.

[0038] 3 formed in the facing portion 211a described above, the rail mounting portion 31 is mounted on the facing portion 211a by screwing the second bolt Bo2 into the second screw hole Nu2 so that the notches 211S3 and the second screw hole Nu2 are aligned in the first and third directions. In other words, the portion of the facing portion 211a where the four notches 211S3 are formed is the position where the rail mounting portion 31 is mounted.

[0039] When viewed from the second direction, the position where the rail mounting part 31 is attached to the facing part 211a of the gripping device 1 according to this embodiment is outside the position where the motor case 222 is attached. Therefore, after the first assembly 2 is formed by attaching the drive part 22 to the support part 21, the task of assembling the second assembly 3 to the first assembly 2 can be easily performed.

[0040] Each of the protrusions 313 shown in FIG. 4 is formed linearly on the main body 311, for example, along the first direction. Furthermore, each of the protrusions 313 according to this embodiment protrudes from the main body 311 toward one side (upper side) in the second direction. The protrusions 313 according to this embodiment are disposed on the rail mounting portion 31 at the furthest one side (upper side) in the second direction. For each of the multiple protrusions 313, for example, after the rail mounting portion 31 is fixed, finishing (for example, polishing) is performed on the end face (upper end face) on one side of the protrusions 313 in the second direction to form the installation surface 31F that forms the same plane. In other words, the installation surface 31F that forms the same plane is formed on the end face (upper end face) on one side of each of the multiple protrusions 313.

[0041] In the rail mounting portion 31 according to this embodiment, after the screw holes Nu3 are formed in the protruding portion 313, the protruding portion 313 is subjected to finishing processing. As a result, the installation surface 31F of the protruding portion 313 is formed as a flat plane without any protruding or recessed portions in the second direction.

[0042] Furthermore, when manufacturing the rail mounting portion 31, for example, after fixing the rail mounting portion 31, when performing finishing (e.g., polishing) on ​​the end face (upper end face) on one side of the protrusion 313, the protrusion 313 is positioned on the side (upper side) of the rail mounting portion 31 closest to one side in the second direction, so there is nothing to get in the way of the finishing, making it easy to perform the finishing.

[0043] Each of the protrusions 313 is formed with a plurality of (three in this embodiment) third screw holes Nu3 extending along the first direction for attaching the rail 32 to the rail attachment portion 31. A third bolt Bo3 is screwed into each of the third screw holes Nu3.

[0044] Of the three third screw holes Nu3, the third screw hole Nu3 located in the center in the first direction is positioned so as to be biased relative to one end 312e1 in the first direction so as to be closer to the other end 312e2. In other words, the third screw hole Nu3 located in the center in the first direction is positioned away from the imaginary center line that bisects the dimension of the rail mounting portion 31 in the first direction and is positioned so as to be closer to the other end 312e2 in the first direction.

[0045] Each of the rails 32 is, for example, a square pillar or a rectangular tube, and is formed to extend along a first direction parallel to the installation surface 31F. The rails 32 (two rails) are arranged to be parallel to each other in a third direction. Each of the rails 32 guides the movement of the shaft 226 along the first direction while restricting the movement of the shaft 226 in the second direction.

[0046] Each of the rails 32 has a plurality of (three in this embodiment) through holes (holes) 32H for attaching the rail 32 to the rail attachment portion 31 formed therein so as to extend along the second direction.

[0047] Of the three through holes 32H, the through hole 32H located at the center in the first direction is positioned so as to be biased relative to one end 32e1 in the first direction so as to be closer to the other end 32e2 in the first direction. In other words, the through hole 32H located at the center in the first direction is positioned away from the imaginary center line that bisects the dimension of the rail 32 in the first direction and is positioned so as to be closer to the other end 32e2 in the first direction.

[0048] First grooves 32D recessed so as to approach each other in the third direction are formed on a pair of side surfaces opposing each other in the third direction in each of the rails 32. Each of the first grooves 32D is formed linearly extending along the first direction.

[0049] Each of the plurality of running bodies 33 is formed in a substantially rectangular parallelepiped shape. Each of the plurality of running bodies 33 includes a running body main body 33M and a pair of end plates 33E that sandwich the running body main body 33M in the first direction.

[0050] 5, each of the running body bodies 33M is formed with a rail accommodating groove 33D1 that extends linearly along the first direction and in which the rail 32 is disposed. The rail accommodating groove 33D1 is disposed at the center of the running body body 33M in the third direction and is formed in the running body body 33M so as to be recessed from the other side (lower side) to one side (upper side) in the second direction.

[0051] Second grooves 33D2 are formed on each of the inner surfaces of the rail accommodating groove 33D1 facing each other in the third direction, the second grooves 33D2 being recessed so as to be spaced apart from each other in the third direction. The second grooves 33D2 of the running body main body 33M and the first grooves 32D of the rail 32 form a first accommodating hole 30H1 that accommodates a plurality of balls 30o. The first accommodating hole 30H1 extends linearly along the first direction.

[0052] Additionally, a second accommodating hole 30H2 that accommodates a plurality of balls 30o is formed inside the running body main body 33M. The second accommodating hole 30H2 is connected to one end of the first accommodating hole 30H1 in the first direction, and is connected to the other end of the first accommodating hole 30H1 in the first direction. The first accommodating hole 30H1 and the second accommodating hole 30H2 form a circulation hole 30H in the rail 32 and the running body 33, through which the plurality of balls 30o circulate. The movement mechanism 30 according to this embodiment employs an endless track system in which the plurality of balls (rolling elements) 30o circulate inside the rail 32 and the running body 33.

[0053] Furthermore, a plurality of (four in this embodiment) fourth screw holes Nu4 into which fourth bolts Bo4 (see FIG. 4) are screwed are formed on one end surface (upper end surface) of the running body main body 33M.

[0054] Each of the end plates 33E closes the circulation hole 30H in the first direction. Each of the end plates 33E is formed with an insertion portion 33I that is inserted into the first groove 32D of the rail 32 shown in FIG.

[0055] Each of the multiple (two in this embodiment) holders 34 is formed in an approximately T-shape when viewed from the first direction, with a first portion 341 extending in the second direction and a second portion 342 extending in the third direction.

[0056] For each of the plurality of holders 34, for example, after fixing the holder 34, a holder installation surface 34F that forms a coplanar surface is formed by performing finishing (for example, polishing) on ​​one end surface (upper end surface) of the holder 34 in the second direction. That is, the holder installation surface 34F that forms a coplanar surface is formed on one end surface (upper end surface) of each of the second portions 342 of the plurality of holders 34.

[0057] A plurality of (four in this embodiment) through holes 34H through which the fourth bolts Bo4 pass are formed in each of the plurality of holders 34. The through holes 34H are formed so as to pass through the holder 34 in the second direction.

[0058] Furthermore, a plurality of (two in this embodiment) fifth screw holes Nu5 into which fifth bolts Bo5 (see FIG. 3) are screwed are formed in each of the plurality of holders 34. The fifth screw holes Nu5H are formed in the holder 34 so as to extend in the second direction.

[0059] In the holder 34 according to this embodiment, after the plurality of through holes 34H and the plurality of fifth screw holes Nu5 are formed in the holder 34, the holder installation surface 34F is formed by performing a finish process on the holder 34. Therefore, the holder installation surface 34F is formed as a flat plane without any protruding or recessed portions in the third direction.

[0060] 6 has, for example, a finger body 351, a base end portion 352 located on the other end side (lower end side) in the second direction of the finger body 351, and a tip end portion 353 located on one end side (upper end side) in the second direction of the finger body 351. The finger body 351 is formed in an elongated shape extending in the second direction, for example.

[0061] The base end portion 352 is attached to the holder 34 so as to contact the holder installation surface 34F. A plurality of (two in this embodiment) through holes 35H through which the fifth bolts Bo5 (see FIG. 3) pass are formed in each of the base end portions 352 of the plurality of fingers 35. The through holes 35H are formed so as to pass through the base end portion 352 in the second direction.

[0062] Tip portion 353 approaches and moves away from the object as running body 33 and holder 34 move in the first direction. When running body 33 and holder 34 approach and move away from the object in the first direction (hereinafter simply referred to as "approaching and moving away"), tip portion 353 can hold the object and can also release the object from tip portion 353.

[0063] Next, the assembly of the above-mentioned moving mechanism 30 will be described with reference to Figures 4 and 7. Figure 7 is a perspective view in which rails 32 and running bodies 33 provided in the moving mechanism 30 shown in Figure 3 are partially cut away.

[0064] First, the worker places one of the multiple rails 32 on the installation surface 31F of the rail mounting portion 31 in the second direction so that the multiple third screw holes Nu3 of the rail mounting portion 31 and the multiple through holes 32H of the rail 32 are aligned in the second direction of the rail 32.

[0065] Next, with the running body 33 attached to the rail 32, the worker places the running body 33 at one end of the rail 32 in the first direction. In this state, as shown in Fig. 7, two through holes 32H are exposed from the running body 33. Then, the worker inserts the third bolts Bo3 into the two exposed through holes 32H, and screws the third bolts Bo3 into the third screw holes Nu3, respectively.

[0066] Next, the worker places the running body 33 at the other end of the rail 32 in the first direction. In this state, one through hole 32H is exposed from the running body 33. In this state, the remaining one of the three through holes 32H is exposed. The worker then inserts a third bolt Bo3 into the exposed through hole 32H and screws the third bolt Bo3 into the third screw hole Nu3, thereby attaching one rail 32 to the rail mounting portion 31. By repeating the same procedure, another rail 32 is attached to the rail mounting portion 31.

[0067] Next, the worker attaches bearing 225 to shaft 226 and then attaches shaft 226 to holder 34. After that, the worker places holder 34 on one of the multiple runners 33 shown in FIG. 4 in the second direction so that the multiple fourth screw holes Nu4 of the runner 33 and the multiple through holes 34H of the holder 34 are aligned with each other in the second direction of one runner 33.

[0068] Next, the worker inserts the fourth bolts Bo4 into the through holes 34H and screws the fourth bolts Bo4 into the fourth screw holes Nu4, thereby attaching the holder 34 to the running body 33. By repeating the same process, another holder 34 is attached to another running body 33.

[0069] Next, the worker inspects whether the holder installation surface 34F is perpendicular to the vertical direction. If the holder installation surface 34F is not perpendicular to the vertical direction during this inspection, for example, all of the fourth bolts Bo4 are unscrewed from the fourth screw holes Nu4 to remove the holder 34 from the running body 33, and then, depending on the inspection results, an adjustment member 36 is placed between the running body 33 and the holder 34 as shown in FIGS. 8 to 10.

[0070] Fig. 8 is a perspective view showing the operation of placing an adjustment member 36 (shim) between the running body 33 and the holder 34 included in the movement mechanism 30 shown in Fig. 3. Fig. 9 is a side view showing a state in which the adjustment member 36 is placed between the running body 33 and the holder 34 at a position spaced apart from the first portion 341 of the holder 34 by the operation shown in Fig. 8. Fig. 10 is a side view showing a state in which the adjustment member 36 is placed between the running body 33 and the holder 34 at a position close to the first portion 341 of the holder 34.

[0071] The adjustment member 36 is made of, for example, a metal material and has a plate shape, and is formed in a rectangular shape when viewed from the second direction. The adjustment member 36 has a through-hole 36H1 that penetrates the adjustment member 36 in the second direction, and a notch 36H2.

[0072] As shown in Figures 8 and 9, when viewed from the first direction, the fourth bolt Bo4 is positioned so as to be spaced apart from the first portion 341, and when the adjustment member 36 is positioned between the holder 34 and the running body 33 so that the fourth bolt Bo4 is inserted into the through hole 36H1 and the notch 36H2, the holder installation surface 34F is adjusted so that the second positive side end E2 of the second portion 342 is higher than the second negative side end E1.

[0073] On the other hand, as shown in Figure 10, when viewed from the first direction, the fourth bolt Bo4 is positioned close to the first part 341, and when the adjustment member 36 is positioned between the holder 34 and the running body 33 so that the fourth bolt Bo4 is inserted into the through hole 36H1 and the notch 36H2, the holder installation surface 34F is adjusted so that the second negative side end E1 of the second part 342 is higher than the second positive side end E2.

[0074] Then, as described above, the adjustment member 36 is disposed between the holder 34 and the traveling body 33, so that the holder installation surface 34F is made perpendicular to the second direction. By the above-described operations, the movement mechanism 30 is formed.

[0075] Next, the work of attaching the second assembly 3, which is the movement mechanism 30, to the first assembly 2 will be described with reference to Fig. 3. Note that in Fig. 3, in order to explain the mechanism of the cam 224, only the bearing 225 and shaft 226 of the second assembly 3 are shown attached to the cam 224 of the first assembly 2. However, at the start of the attachment work, the shaft 226 to which the bearing 225 is attached is attached to the holder 34 of the second assembly 3 as described above.

[0076] First, the worker places the movement mechanism 30 on the support part 21 in the second direction so that the notch 211S3 of the facing part 211a and the second screw hole Nu2 of the rail attachment part 31 align with each other in the second direction.

[0077] Next, the worker inserts the second bolts Bo2 into each of the notches 211S3 and screws the second bolts Bo2 into the second screw holes Nu2, thereby attaching the second assembly 3 to the first assembly 2 and forming the gripping device 1.

[0078] Next, a case will be described in which an object (workpiece) is gripped by the gripping device 1 having the above-described configuration. In the initial state of the gripping device 1, as shown in Fig. 1, the pair of traveling bodies 33 and the pair of holders 34 are disposed at positions furthest apart in the first direction, and the bearing 225 is disposed on one end 224s side of the pair of cam grooves 244D.

[0079] From this initial state, the motor 221 is driven, and the drive shaft 221a is rotated about the axis 211z by the driving of the motor 221. The rotation of the drive shaft 221a causes the cam 224 fixed to the drive shaft 221a to rotate about the axis 211z.

[0080] Then, as the cam 224 is driven to rotate, the bearing 225 moves from one end 224s side to the other end 224e side along the extending direction of the cam groove 224D.

[0081] At this time, the shaft 226, which has a bearing 225 press-fitted into one end thereof, is permitted to move in the first direction by the rail 32, but is restricted from moving in the second direction. The movement range of the shaft 226 in the first direction is limited by the shaft insertion hole 311H1. Therefore, the pair of running bodies 33 move toward each other in the first direction. As the pair of running bodies 33 move, the pair of fingers 35 also move toward each other in the first direction, thereby gripping an object placed between the pair of fingers 35. In such a gripping device 1, when releasing the object, the motor 221 is reversely driven to move the pair of running bodies 33 apart in the first direction and move the pair of fingers 35 apart in the first direction.

[0082] As described above, the gripping device 1 according to this embodiment has the following configuration. The gripping device 1 includes a movement mechanism 30 that moves multiple fingers 35 closer to and farther apart. The movement mechanism 30 includes at least a rail mounting portion 31 and multiple rails 32 attached to the rail mounting portion 31. The multiple rails 32 are attached to the same flat installation surface 31F of the rail mounting portion 31. Therefore, compared to conventional gripping devices in which multiple rails are attached to multiple installation surfaces provided on the rail mounting portion, the gripping device 1 according to this embodiment can reduce the installation error of the multiple fingers 35 relative to the installation surface 31F of the rail mounting portion 31, thereby suppressing misalignment of the tips 353 of the multiple fingers 35. As a result, the gripping device 1 according to this embodiment can grip small objects (workpieces) that conventional gripping devices 1 could not. In other words, the gripping device 1 according to this embodiment can improve the accuracy of gripping an object (workpiece) using the multiple fingers 35.

[0083] Moreover, the drive unit 22 of the gripping device 1 according to this embodiment is an electric type equipped with a motor 221. Therefore, the gripping device 1 according to this embodiment consumes less energy and is quieter than an air-driven gripping device. Furthermore, the electric gripping device 1 can accurately control the gripping of the target object (workpiece), so it can accurately control the gripping force and the gripping position.

[0084] Furthermore, in the gripping device 1 according to this embodiment, the movement mechanism 30 further includes a plurality of runners 33 attached to a plurality of rails 32 and a plurality of holders 34 attached to the plurality of runners 33 and holding fingers 35. Of the plurality of rails 32 and the plurality of runners 33, one runner 33 is attached to one rail 32, and another runner 33 is attached to another rail 32. Of the plurality of runners 33 and the plurality of holders 34, one holder 34 is attached to one runner 33, and another holder 34 is attached to another runner 33. Therefore, in the gripping device 1 according to this embodiment, the holder 34, the runner 33, and the rail 32 can be individually assembled, thereby improving assembly workability. Furthermore, when adjusting the holder installation surface 34F, it is sufficient to remove the holder 34 from the runner 33 and place the adjustment member 36 therebetween, which facilitates the adjustment of the holder installation surface 34F using the adjustment member 36.

[0085] Furthermore, in the gripping device 1 according to this embodiment, each of the multiple rails 32 is formed to extend along a first direction parallel to the installation surface 31F, and a through-hole (hole) 32H for attaching the rail 32 to the rail mounting portion 31 is formed in the rail 32 to extend along a second direction perpendicular to the installation surface 31F. On the other hand, in the technology described in Patent Document 1, the screw hole for attaching the rail 32 to the rail mounting portion 31 extends along a third direction. Therefore, in the technology described in Patent Document 1, when attaching one rail 32 of the multiple rails 32 to the rail mounting portion 31, a bolt is screwed into the screw hole from one side of the third direction, and then when attaching another rail 32 of the multiple rails 32 to the rail mounting portion 31, a bolt is screwed into the screw hole from the other side of the third direction, which requires the worker to move or the part to move, resulting in poor workability. On the other hand, in the gripping device 1 according to this embodiment, when attaching one rail 32 of the multiple rails 32 to the rail mounting portion 31, the third bolt Bo3 is inserted into the through hole 32H from one side in the second direction and screwed into the third screw hole Nu3, and then, when attaching another rail 32 of the multiple rails 32 to the rail mounting portion 31, the third bolt Bo3 is inserted into the through hole 32H from one side in the second direction and screwed into the third screw hole Nu3. As a result, in the gripping device 1 according to this embodiment, when attaching the multiple rails 32 to the rail mounting portion 31, the worker does not need to move and there is no need to move parts, thereby improving workability.

[0086] Furthermore, in the gripping device 1 according to this embodiment, the holder 34 has a fourth screw hole Nu4 for attaching the holder 34 to the running body 33, and the fourth screw hole Nu4 is formed in the holder 34 so as to extend along the second direction. Therefore, in the gripping device 1 according to this embodiment, when attaching the holder 34 to the running body 33, a fourth bolt (bolt) Bo4 is screwed into the fourth screw hole Nu4 from one side in the second direction. As a result, the insertion direction of the fourth bolt (bolt) Bo4 when attaching the holder 34 to the running body 33 is the same as the insertion direction of the third bolt (bolt) Bo3 when attaching the rail 32 to the rail attachment portion 31, thereby improving workability.

[0087] Furthermore, in the gripping device 1 according to this embodiment, a plurality of (three in this embodiment) through holes (holes) 32H for attaching the rail 32 to the rail attachment portion 31 are formed in one rail 32, and when the running body 33 is attached to the rail 32 and the running body 33 is disposed at one end of the rail 32 in the first direction, one or more (two in this embodiment) through holes (holes) 32H are exposed from the running body 33, and when the running body 33 is disposed at the other end of the rail 32 in the first direction, the remaining (one in this embodiment) through hole (hole) 32H is exposed from the running body 33. Therefore, in this embodiment, it is possible to ensure ease of assembly of the gripping device 1 by exposing all of the plurality of through holes 32H, and to reduce the size of the gripping device 1 in the first direction.

[0088] Furthermore, in the gripping device 1 according to this embodiment, the rail mounting portion 31 includes a main body 311 and a protruding portion 313 formed to protrude from the main body 311, and the installation surface 31F is formed on the protruding portion 313. Therefore, the gripping device 1 according to this embodiment can reduce the area of ​​the installation surface 31F on which finishing processes such as polishing are performed. As a result, the gripping device 1 according to this embodiment can reduce the cost related to finishing processes of the installation surface 31F, and can also improve workability during assembly because the worker can easily identify the location where the rail 32 is to be attached.

[0089] Furthermore, in the rail mounting portion 31 of the gripping device 1 according to this embodiment, the protruding portion 313 of the rail mounting portion 31 is disposed on the furthest side (upper side) in the second direction. Therefore, in the gripping device 1 according to this embodiment, the protruding portion 313 of the rail mounting portion 31 does not have any part that gets in the way of finishing work such as polishing, which improves the workability of the finishing work.

[0090] In addition, in the moving mechanism 30 of the gripping device 1 of this embodiment, a first accommodating hole 30H1 is formed in a linear shape in the rail 32 and the running body 33, in which a plurality of balls (rolling bodies) 30o are accommodated, and a second accommodating hole 30H2 is formed in the running body 33, connected to the first positive side end of the first accommodating hole 30H1 and the first negative side end of the first accommodating hole 30H1, in which a plurality of balls (rolling bodies) 30o are accommodated, and the first accommodating hole 30H1 and the second accommodating hole 30H2 form a circulation hole 30H in which the plurality of balls (rolling bodies) 30o circulate inside the rail 32 and the running body 33. In the endless track type moving mechanism 30 having such a configuration, the ball (rolling element) 30o circulates inside the rail 32 and the traveling body 33. Therefore, regardless of the initial position of the ball 30o at the time of manufacturing the gripping device 1, the movement range of the ball 30o is not limited. This keeps the sliding resistance of the ball 30o constant at all times, thereby suppressing variations in the gripping force of the fingers 35. On the other hand, in a conventional finite track type moving mechanism in which the ball receiving holes are formed only by linear first receiving holes that receive multiple balls (rolling elements) in the rail and traveling body, the range over which the ball (rolling element) can move with little resistance is limited by the initial position of the ball (rolling element) when the gripping device starts operating. Therefore, as the opening and closing operations are repeated, the initial position of the ball shifts, changing the range over which the ball can move with little resistance. This can cause variations in the gripping force of the fingers in the finite track type moving mechanism, making it difficult to precisely control the finger gripping force.

[0091] [Second embodiment] Next, the rail mounting portion 31A of the gripping device 1A according to the second embodiment will be described with reference to Fig. 11. Fig. 11 is a perspective view of the rail mounting portion 31A of the gripping device 1A according to the second embodiment. Note that in the configuration of the gripping device 1A according to the second embodiment, the same components as those of the gripping device 1 according to the first embodiment will be assigned the same reference numerals and their description will be omitted, and only the different components will be described below.

[0092] The rail mounting portion 31A is arranged on one side (upper side) of the rail mounting portion 31A in the second direction, and has a plate-shaped main body 311A ​​that is formed in a rectangular shape when viewed from the second direction, a frame-shaped portion 312, and multiple (two in this embodiment) positioning portions 314 that protrude from the main body 311A.

[0093] The main body 311A ​​is formed with a shaft insertion hole 311H1 and a through hole 311H2.

[0094] The positioning portions 314 determine the positions of the rails 32 in the third direction of the main body 311A. Each of the positioning portions 314 is formed linearly on the main body 311A ​​along, for example, the first direction. Furthermore, each of the positioning portions 314 according to this embodiment protrudes from the main body 311A ​​to one side (upward) in the second direction.

[0095] Furthermore, the main body 311A ​​is formed with a plurality of (six in this embodiment) third screw holes Nu3 extending along the first direction for attaching the rail 32 to the rail attachment portion 31A. A third bolt Bo3 is screwed into each of the third screw holes Nu3.

[0096] In the main body 311A ​​according to this embodiment, after the third screw hole Nu3 is formed in the main body 311A, a finishing process (for example, polishing) is performed on one end face (upper end face) of the main body 311A ​​to form the installation face 31FA that forms a flat surface. Therefore, the installation face 31FA is formed as a flat surface that does not have any protruding or recessed portions in the second direction.

[0097] In the gripping device 1A of this embodiment, when attaching a rail 32 to the rail mounting portion 31A, the worker first places the rail 32 between multiple (two in this embodiment) positioning portions 314 in the second direction of the main body 311A.

[0098] Next, the worker can position the rail 32 in the third direction by moving the rail 32 in the third direction and bringing the rail 32 into contact with the positioning portion 314. Therefore, the gripping device 1A according to this embodiment can facilitate the positioning operation of the rail 32 relative to the rail mounting portion 31A.

[0099] [Third embodiment] Next, the holder 34B of the gripping device 1B according to the third embodiment will be described with reference to Fig. 12. Fig. 12 is a perspective view showing the holder 34B of the gripping device 1B according to the third embodiment. Note that in the configuration of the gripping device 1B according to the third embodiment, the same components as those of the gripping device 1 according to the first embodiment will be assigned the same reference numerals and description thereof will be omitted, and only different components will be described below.

[0100] When viewed from the first direction, each of the multiple holders 34B in this embodiment has a first portion 341 extending in the second direction, a second portion (holder main body) 342B extending in the third direction, and multiple (two in this embodiment) holder protrusions 343 protruding from the second portion 342B.

[0101] A plurality of (two in this embodiment) through holes 34H, through which the fourth bolts Bo4 pass, are formed in each of the second portions (holder bodies) 342B of the holder 34B. The through holes 34H are formed to pass through the holder 34B in the second direction.

[0102] Furthermore, a plurality of (two in this embodiment) fifth screw holes Nu5 into which fifth bolts Bo5 are screwed are formed in each of the holder protrusions 343. The fifth screw holes Nu5H are formed in the holder 34 so as to extend in the second direction.

[0103] In addition, in the holder 34B of the gripping device 1B according to this embodiment, the holder protrusion 343 is disposed on the uppermost side in the second direction.

[0104] In the holder 34B according to this embodiment, after the through holes 34H and the fifth screw holes Nu5 are formed in the holder 34B, the holder installation surface 34FB is formed by performing a finishing process on the holder 34B. Therefore, the holder installation surface 34FB is formed as a flat plane without any protruding or recessed portions in the second direction.

[0105] In the gripping device 1B according to this embodiment, each of the holders 34B includes a second portion (holder main body) 342B and a holder protrusion 343 formed to protrude from the second portion (holder main body) 342B. The fingers 35 are attached to the holder installation surfaces 34FB of the holders 34B, which form the same plane, and the holder installation surfaces 34FB are formed on the holder protrusions 343. Therefore, the gripping device 1B according to this embodiment can reduce the area of ​​the holder installation surfaces 34FB on which finishing processes such as polishing are performed. As a result, the gripping device 1B according to this embodiment can reduce the cost of finishing the holder installation surfaces 34FB and can improve workability during assembly because the worker can easily identify the locations where the fingers 35 are attached.

[0106] Furthermore, in the holder 34B of the gripping device 1B according to this embodiment, the holder protrusion 343 is disposed at the uppermost position in the second direction. Therefore, in the gripping device 1B according to this embodiment, the holder protrusion 343 does not have any part that gets in the way of finishing work such as polishing, thereby improving the workability of the finishing work.

[0107] [Fourth embodiment] Next, a gripping device 1C according to a fourth embodiment will be described with reference to Fig. 13. Fig. 13 is a perspective view showing the assembly of the gripping device 1C according to the fourth embodiment. Note that in the configuration of the gripping device 1C according to the fourth embodiment, the same components as those of the gripping device 1 according to the first embodiment will be assigned the same reference numerals and description thereof will be omitted, and only different components will be described below.

[0108] A first assembly 2C of a gripping device 1C according to this embodiment has a support part 21C to which a movement mechanism 30 is attached, and a drive part 22 which is a drive source of the movement mechanism 30.

[0109] The support unit 21C according to this embodiment includes a housing 213 that houses the motor case 222. The housing 213 includes a side housing 2131 that covers the side of the drive unit 22 and has openings 213H1 and 213H2 at both ends in the second direction, a bottom housing 2132 that is disposed at the other opening 213H2 of the side housing 2131 and covers the bottom of the drive unit 22, and a top housing 2133 that is disposed at one opening 213H1 of the side housing 2131 and covers the top of the drive unit 22. In the example shown in FIG. 13 , the bottom housing 2132 closes the opening 213H2, and the top housing 2133 closes the opening 213H1. However, the opening 213H1 only needs to be closed by the movement mechanism 30, and does not have to be closed by the top housing 2133.

[0110] The side housing 2131 is formed in a hollow, approximately rectangular cylindrical shape. Furthermore, the side housing 2131 is formed with through holes 2131H that penetrate the side housing 2131 in the second direction. The side housing 2131 according to this embodiment has multiple (four in this embodiment) through holes 2131H. The through holes 2131H are arranged at the four corners of the side housing 2131 when viewed from the second direction.

[0111] The bottom housing 2132 is plate-shaped and is formed in a substantially rectangular shape when viewed from the second direction. Furthermore, the bottom housing 2132 is formed with through holes 2132H that penetrate the bottom housing 2132 in the second direction. The bottom housing 2132 according to this embodiment has a plurality of through holes 2132H (four in this embodiment). The through holes 2132H are arranged at the four corners of the bottom housing 2132 when viewed from the second direction.

[0112] The top housing 2133 is plate-shaped and has a substantially rectangular shape when viewed from the second direction. Furthermore, the top housing 2133 has through holes 2133H formed therein, which penetrate the top housing 2133 in the second direction. The top housing 2133 according to this embodiment has a plurality of through holes 2133H (four in this embodiment). The through holes 2133H are located at the four corners of the top housing 2133 when viewed from the second direction.

[0113] The gripping device 1C has at least one second bolt Bo2C for attaching the second assembly 3 to the first assembly 2C by passing through the top housing 2133, the bottom housing 2132, and the side housing 2131. The gripping device 1C according to this embodiment has multiple (four in this embodiment) second bolts Bo2C.

[0114] The second bolt Bo2C extends in the second direction. The second bolt Bo2C is inserted through the through holes 3131H, 3132H, and 3133H in the second direction. The tip of the second bolt Bo2C is threaded into the second screw hole Nu2 formed in the frame portion 312 of the rail mounting portion 31. This attaches the second assembly 3 to the first assembly 2C, completing the gripping device 1C. When attaching the second assembly 3 to the first assembly 2C, the second bolt Bo2C simply needs to penetrate the bottom housing 2132 and the side housing 2131 and be threaded into the second screw hole Nu2 of the second assembly 3. In other words, in this embodiment, it is not essential that the second bolt Bo2C penetrate the top housing 2133. For example, the top housing 2133 may be sandwiched and fixed between the side housing 2131 and the second assembly 3.

[0115] As described above, the gripping device 1C of this embodiment comprises a first assembly 2C having a support part 21C to which the moving mechanism 30 is attached and a drive part 22 that is the drive source of the moving mechanism 30, and a second assembly 3 that is the moving mechanism 30, and the support part 21C comprises a housing 213 that accommodates a motor case 222, and the housing 213 comprises a side housing 2131 that covers the side of the drive part 22 and has openings 213H1 and 213H2 at both ends in the second direction, a bottom housing 2132 that is positioned in the other opening 213H2 of the side housing 2131 and covers the bottom of the drive part 22, and a top housing 2133 that is positioned in one opening 213H1 of the side housing 2131 and covers the top of the drive part 22, and has at least one bolt that passes through the bottom housing 2132 and the side housing 2131 to attach the second assembly 3 to the first assembly 2C. In the example shown in FIG. 13, four second bolts Bo2C for attaching the second assembly 3 to the first assembly 2C penetrate the top housing 2133 in addition to the bottom housing 2132 and the side housing 2131.

[0116] In a conventional gripping device, for example, a bolt is inserted from below to complete the first assembly, and then a rail mounting portion (part of the second assembly) is placed on top of the first assembly. Then, a bolt is inserted from above to attach the rail mounting portion to the first assembly. The second assembly (excluding the rail mounting portion) is then placed on top of the rail mounting portion, and then attached to the rail mounting portion with another bolt to complete the gripping device. In other words, in a conventional gripping device, because the assembly order is restricted by bolts from both above and below, it is difficult to inspect the second assembly individually. In other words, with this installation method, the entire gripping device must be assembled before inspection, resulting in a large cumulative error during inspection. In contrast, the gripping device 1C of this embodiment can inspect the second assembly 2C individually. As a result, the gripping device 1C of this embodiment can inspect the second assembly 2C accurately with little cumulative error. Furthermore, even if the inspection results in deviation from the appropriate range, the effort required for correction can be minimized.

[0117] In the gripping devices 1, 1A, 1B, and 1C according to the above-described embodiments, the gripping devices 1, 1A, 1B, and 1C have been described as being mounted on a six-axis articulated robot. However, the gripping devices 1, 1A, 1B, and 1C according to the present embodiments are not limited to this. For example, the gripping devices 1, 1A, 1B, and 1C can be mounted on industrial robots such as horizontal articulated robots, parallel link robots, Cartesian robots, and collaborative robots.

[0118] Furthermore, the gripping devices 1, 1A, 1B, and 1C according to the above-described embodiments have been described as having two fingers 35. However, the gripping devices 1, 1A, 1B, and 1C according to the present invention are not limited to this. For example, the gripping devices 1, 1A, 1B, and 1C may have three fingers 35, or four or more fingers 35.

[0119] Furthermore, in the gripping devices 1, 1A, 1B, and 1C according to the above embodiments, each of the multiple rails 32 has multiple through holes 32H formed therein for attaching the rail 32 to the rail mounting portion 31, and the rail mounting portion 31 has multiple third screw holes Nu3 formed therein for attaching the rail 32 to the rail mounting portion 31. However, the gripping device 1 according to the present embodiment is not limited to this. For example, each of the multiple rails 32 may have multiple screw holes (holes) formed therein for attaching the rail 32 to the rail mounting portion 31, and a separate component may be provided for attaching the rail 32 to the rail mounting portion 31.

[0120] Furthermore, the present invention is not limited to the above-described embodiments. Configurations that appropriately combine the components of the above-described embodiments are also included in the present invention. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments, and various modifications are possible. [Explanation of symbols]

[0121] 1, 1A, 1B, 1C gripping device, 22 drive unit, 213 housing, 213H1 opening, 213H2 opening, 2131 side housing, 2132 bottom housing, 2133 top housing, 222 motor case, 30 movement mechanism, 31, 31A rail mounting portion, 32 rail, 32H through hole (hole), 33 running body, 34, 34B holder, 342B second part (holder body), 343 holder protrusion, 34F, 34FB holder installation surface, 35 finger, Bo2 second bolt (bolt), Bo4 fourth bolt (bolt), Nu1 first screw hole (screw hole), Nu2 second screw hole (screw hole), Nu3 third screw hole (screw hole), Nu4 fourth screw hole (screw hole)

Claims

1. a movement mechanism for moving the plurality of fingers closer to and apart from each other; The moving mechanism includes at least A rail mounting portion; a plurality of rails attached to the rail attachment portion; Equipped with The plurality of rails are respectively attached to installation surfaces that form the same plane in the rail attachment portion. gripping device.

2. The moving mechanism includes: a plurality of running bodies attached to the plurality of rails; a plurality of holders attached to the plurality of traveling bodies and holding the fingers; Furthermore, Among the plurality of rails and the plurality of traveling bodies, one traveling body is attached to one of the rails, and another traveling body is attached to another of the rails; Among the plurality of running bodies and the plurality of holders, one of the holders is attached to one of the running bodies, and another of the holders is attached to another of the running bodies. The gripping device according to claim 1 .

3. Each of the rails is formed to extend along a first direction parallel to the installation surface, a hole for attaching the rail to the rail attachment portion is formed in the rail so as to extend along a second direction perpendicular to the installation surface; The gripping device according to claim 2 .

4. The holder has a screw hole for attaching the holder to the traveling body, the screw hole is formed in the holder so as to extend along the second direction; The gripping device according to claim 3.

5. a plurality of holes for attaching the rail to the rail attachment portion are formed in one rail; When the running body is attached to the rail, one or more of the holes are exposed from the running body when the running body is disposed at one end of the rail in the first direction, and when the running body is disposed at the other end of the rail in the first direction, the remaining holes are exposed from the running body. The gripping device according to claim 3.

6. a first assembly having a support part to which the movement mechanism is attached and a drive part that is a drive source of the movement mechanism; a second assembly that is the movement mechanism; Equipped with the support portion includes a housing that accommodates a motor case, The housing includes a side housing that covers the sides of the drive unit and has openings on both ends in the second direction, a bottom housing that is disposed in the other opening of the side housing and covers the bottom of the drive unit, and a top housing that is disposed in one opening of the side housing and covers the top of the drive unit, at least one bolt passing through the bottom housing and the side housing to attach the second assembly to the first assembly; The gripping device according to claim 1 .

7. The rail mounting portion is The main body and a protrusion formed to protrude from the main body; Equipped with The installation surface is formed on the protrusion. The gripping device according to claim 1 or 2.

8. Each of the holders comprises: A holder body; a holder protrusion formed to protrude from the holder main body; Equipped with The plurality of fingers are respectively attached to holder installation surfaces that form the same plane in the plurality of holders, The holder installation surface is formed on each of the holder protrusions. The gripping device according to claim 2 .

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