Robot hand

Abstract

In a device configuration where the interrelationship spacing between actuators (which act as fingers) is variable, we propose a method for reliably and firmly positioning the actuators relative to the frame on which they are mounted. [Solution] A robot hand comprising a plurality of finger portions made of fluid pressure actuators and a frame to which the finger portions are attached, wherein the base end of each of the plurality of fingers is attached to the frame, and the distance between the fingertips of the plurality of fingers can be adjusted by the operation of the fluid pressure actuators, the frame has a plurality of mounting parts for attaching the base ends of the fingers, each of the mounting parts has a plurality of mounting holes for fixing the base end of the finger, and the mounting holes are arranged in a direction along the operating direction of the fluid pressure actuators fixed to the mounting holes.

Description

Technical Field

[0001] The present invention relates to a robot hand.

Background Art

[0002] In recent years, general-purpose robots that perform operations such as grasping, lifting, transporting, and supporting objects have been used in various fields such as manufacturing and logistics. In particular, regarding the robot hand that bears the part that mimics the function of the palm, which is the part of the robot beyond the human wrist, various proposals have been made.

[0003] Now, in recent logistics where various workpieces with different shapes and sizes are handled, when applying a robot hand, it is required to securely grasp various workpieces. For example, it is required to adjust the mutual interval of the fingers in the hand according to the size of the workpiece and vary the grasping range with the fingers according to the size of the workpiece.

[0004] In Patent Document 1, it is proposed to change the mutual interval of two actuators by moving one of a pair of two actuators serving as fingers on a rail.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Patent Document 1 illustrates a mechanism for fixing an actuator to a rail by bolting, but there was room for improvement in that it was difficult to reliably fix its position on a sliding rail. For example, when the workpiece to be gripped by the actuator is relatively heavy, the force generated by the actuator naturally becomes large, and the reaction force when gripping the workpiece is applied to the rail fixing part, so there was a risk that the fixing position would easily shift.

[0007] Therefore, the present invention aims to propose a method for reliably and firmly positioning the actuators relative to the frame on which they are attached, in a device configuration in which the distance between the actuators, which act as fingers, is variable. [Means for solving the problem]

[0008] The inventors diligently studied the structure of a robot hand that could solve the above problems and found that it is effective to provide mounting holes for attaching fingers (actuators) to the frame and to devise a structure for these mounting holes. The present invention is derived from the above findings, and its gist is as follows.

[0009] 1. Multiple finger-like parts consisting of fluid pressure actuators, The frame to which the aforementioned finger portion is attached, A robotic hand having, The base end of each of the aforementioned multiple fingers is attached to the frame, and the distance between the fingertips of the multiple fingers can be adjusted by the operation of the fluid pressure actuator. The frame has a plurality of mounting parts for attaching the base end of the finger, Each of the aforementioned mounting parts has a plurality of mounting holes for fixing the base end of the finger, The mounting holes are arranged in a direction along the operating direction of the fluid pressure actuator fixed to the mounting holes. Robot hand.

[0010] 2. The robot hand according to claim 1, wherein the mounting portion has a saddle that fits detachably into the mounting hole, and the base end of the finger is attached to the saddle to fix the finger to the mounting hole.

[0011] 3. The robot hand according to 1 or 2, wherein the joint is a metal fitting having a through hole on the central axis of a cylinder, a protrusion around the opening of the through hole that engages with the opening of the mounting hole, and one of the bottom surfaces of the cylinder has an inclined surface that is inclined with respect to the cylinder axis, and the through hole extends in a direction inclined with respect to a perpendicular to the surface of the frame. [Effects of the Invention]

[0012] According to the present invention, when the distance between actuators that act as fingers is made variable, the positioning of the actuators attached to the frame can be reliably and firmly achieved. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of a robot hand and a robot arm to which the robot hand is attached, according to the present invention. [Figure 2] This is a perspective view showing the structure of a robotic hand, which is one embodiment of the present invention. [Figure 3] This diagram shows the operation when a finger acts as a fluid pressure actuator. [Figure 4] This is a top view of the robot hand of the present invention. [Figure 5] This is a cross-sectional view along the VV line in Figure 4. [Figure 6] This is a perspective view showing the frame of a robot hand as a standalone unit. [Figure 7] This is an exploded perspective view showing the finger attachment structure to the frame. [Figure 8] This is a perspective view of the frame. [Modes for carrying out the invention]

[0014] The robotic hand of the present invention is attached to the tip of a robotic arm and used. The structure of this robotic arm is not particularly limited. For example, the robotic arm 1 shown in FIG. 1 can be applied. The robotic arm 1 will be described below with reference to FIG. 1.

[0015] <Robotic arm 1> FIG. 1 is a perspective view of a robotic arm 1 having a robotic hand 2 according to the present invention. As shown in FIG. 1, the robotic arm 1 has a base 11 attached to a base (not shown), an arm 13a extending from the base 11 via a joint 12a, and an arm 13b extending from the arm 13a via a joint 12b. Thus, the robotic hand 2 is attached to the tip of the connected arm 13b via a joint 12c. Next, the robotic hand 2 according to the present invention will be described in detail with reference to the drawings.

[0016] <Robotic hand 2> As shown in FIG. 1, the robotic hand 2 has gripping means 3 for gripping a workpiece (not shown). The gripping means 3 is composed of a plurality of, in this embodiment, four fingers 30a to 30d attached to the hand body 20. The hand body 20 has a frame for attaching the fingers 30a to 30d inside the cover 21.

[0017] [Fingers 30a to 30d] As shown in Figure 2, with the cover 21 of the hand body 20 removed, the base ends of the fingers 30a to 30d are attached to the frame 4 fixed to the joint 12c of the robot arm 1 described above. The fingers 30a to 30d are rod-shaped bodies that extend uniaxially from their base to their tip. In this embodiment, each of the fingers 30a to 30d is a fluid pressure actuator capable of bending from the uniaxial extension shown in Figure 2 to a direction different from the uniaxial extension, as shown in Figure 3. For the fluid pressure actuator, for example, a "rubber actuator" consisting of a rubber tube and a high-strength fiber sleeve surrounding it can be used. That is, by introducing working fluid into the rubber tube from the inlet 31, it is possible to give it a bending motion toward the tip, as shown by the dashed line in Figure 3.

[0018] By applying the above actions to each finger, as shown in Figure 2, the distance d1 between opposing fingers 30a and 30d, and the distance d2 between fingers 30b and 30c can be varied to enable a strong grip on the workpiece or, conversely, a soft grip using the fingertips. The working fluid is appropriately determined according to the type of workpiece and fluid pressure actuator, but compressed air is used as an example.

[0019] [Frame 4] Frame 4, in this embodiment shown in Figure 2, is a plate-like body, for example, made of metal, with reinforcing flange portions 40 on both sides of a rectangular thick plate. Frame 4 has mounting portions 5 to 8 for attaching the base ends of the fingers 30a to 30d described above. Each of these mounting portions 5 to 8 is provided with multiple mounting holes into which the base ends of the fingers are inserted and fixed. Hereinafter, mounting portions 5 to 8 will be described in detail with reference to the drawings. In the following, mounting portions 5 to 8 will be described using mounting portion 7 as a representative. That is, the structures of mounting portions 5, 6, and 8 other than mounting portion 7 are basically the same as those of mounting portion 7, so the same components are denoted by the same reference numerals and their descriptions will be omitted.

[0020] Figure 4 shows a top view of the robot hand 2, and Figure 5 shows a cross-sectional view of the VV line in Figure 4. As shown in the figures, the mounting portion 7 is provided with multiple mounting holes H1 to H5, five in this embodiment, for inserting and fixing the base end portion 32 of the finger 3c. The mounting holes H1 to H5 are holes that penetrate the frame 4 in the thickness direction with the same square opening in the illustrated example, and as shown in the perspective view of the frame 4 only in Figure 6, the five holes are arranged in a line with partial overlap. Note that the mounting holes H1 to H5 may be arranged adjacent to each other at a predetermined interval without any overlap. Furthermore, the number of mounting holes can be arbitrary and can be increased or decreased according to the set movable range of the finger relative to the frame 4.

[0021] Here, the orientation of the mounting holes H1 to H5 is aligned with the direction of operation of the actuator of the finger 3c fixed to the mounting hole. In this embodiment, since the direction of operation of the finger actuator is on the distance d2 between the fingers shown in Figure 2, the mounting holes H1 to H5 are arranged in a direction aligned with this actuator's direction of operation.

[0022] Therefore, by appropriately selecting a mounting hole from mounting holes H1 to H5 to fix finger 3c, the fixing position of finger 3c can be arbitrarily set in the direction of the arrangement of mounting holes H1 to H5. In other words, the fixing position of finger 3c can be appropriately changed in the direction of the arrangement of mounting holes H1 to H5, and the fixing position of finger 3c will move forward and backward relative to the opposing finger 3b. By performing a similar operation on the mounting part 6 related to finger 3b, it is possible to adjust the distance d2 between fingers 3b and 3c, as shown in Figure 2, by making it smaller or larger. For example, when a finger is fixed to mounting hole H1 in each of mounting parts 6 and 7, the distance d2 between fingers is minimized, and when a finger is fixed to mounting hole H5 in each of mounting parts 6 and 7, the distance d2 between fingers is maximized.

[0023] Furthermore, the same attachment operation for fingers 3b and 3c on attachment parts 6 and 7 can be performed for fingers 3a and 3d on attachment parts 5 and 8, and the adjustment of the relative distance d1 between fingers 3a and 3d shown in Figure 2 can be achieved in the same way.

[0024] Next, the means for fixing the finger 3c to the mounting holes H1 to H5 will be explained in detail with reference to Figure 7. Here again, the means for inserting and fixing the finger 3c is the same for mounting parts 5, 6, and 8 other than mounting part 7, so the explanation for mounting parts 5, 6, and 8 will be omitted. Figure 7 is an exploded perspective view showing the mounting structure of the finger 3c in the mounting portion 7. As shown in Figure 7, the finger 3c is fixed to one of the mounting holes H1 to H5 by engaging the base end 32 of the finger 3c with the shim 9 that fits into the mounting hole.

[0025] As shown in Figure 9 in its perspective view, the component 9 is a fitting in this embodiment that has a through hole 90 on the central axis of a short cylinder, and has a protruding portion 91 that has a contour shape (square) that matches the opening shape (square in the illustrated example) of the mounting holes H1 to H5. Furthermore, in this embodiment, one of the two bottom surfaces of the cylinder is an inclined surface 92 with respect to the cylinder axis (hereinafter referred to as the inclined surface), and the other is a surface 93 perpendicular to the cylinder axis (hereinafter referred to as the plane). The protruding portion 91 has the above-mentioned protrusions that project in a direction perpendicular to the inclined surface 92.

[0026] In this embodiment, the two pieces 9 described above are used in combination to fix the finger 3c to the mounting hole H5, for example. That is, as shown in Figure 7, the inclined surfaces 93 of both pieces 9 are inserted toward the mounting hole H5 so that the frame 4 is sandwiched between the two pieces 9. At this time, the protrusions 91 of each piece 9 fit precisely into the opening of the mounting hole H5, so that the pieces 9 are inserted correctly into the mounting hole H5 without any misalignment. As a result, the through holes 90 of the two pieces 9 that fit into the opening of the mounting hole H5, sandwiching the frame 4 from above and below, become a single connected bolt hole. A bolt 10 is passed through this bolt hole, and the bolt 10 is engaged with the female threaded portion 33 formed on the central axis of the base end 32 of the finger 3c, thereby fastening the two pieces 9 and the finger 3c that sandwich the frame 4 together with the bolt 10.

[0027] Here, as the inclined surface 92 of the frame 9 is positioned in contact with the surface of the frame 4, the through-hole 90 of the frame 9 is positioned to extend in a direction inclined with respect to the perpendicular L of the surface of the frame 4. For example, in the illustrated example, the through-axis l of the through-hole 90 of the frame 9 is inclined outward from the frame 4 in the direction of the mounting hole arrangement with respect to the perpendicular L of the surface of the frame 4. By fastening the two frames 9 and the fingers 3c that sandwich the frame 4 together via bolts 10 on this through-axis l, the fingers 3c are mounted inclined with respect to the frame 4, as shown in Figure 5.

[0028] As described above, the inclination of the through-axis l of the through-hole 90 of the finger 9 with respect to the perpendicular L of the frame 4 can be adjusted by the inclination of the inclined surface 92 of the finger 9 with respect to the through-axis l of the through-hole 90. If the inclination of the inclined surface 92 is zero (flat), the finger 3c will extend perpendicular to the surface of the frame 4 (perpendicular L), and the inclination with respect to the perpendicular L will become stronger as the inclination increases. Thus, the mutual spacing d1 and d2 of the fingers described above can also be adjusted by adjusting the inclination of the finger 3c with respect to the surface of the frame 4.

[0029] Furthermore, the direction of the inclination of finger 3c relative to frame 4 (outside or inside the frame) can also be changed by changing the direction of the inclination of the inclined surface 92.

[0030] In the above embodiment, the opening shape of the mounting hole can be arbitrary, and the shape is not limited as long as the engagement with the protrusion 91 of the saddle 9 is performed accurately. In particular, a shape that enables engagement in which the saddle 9 is restricted to a predetermined orientation is preferred, and a triangular or more angular shape is preferred over a circular shape. [Explanation of symbols]

[0031] 1. Robot arm 2. Robot Hand 3 Gripping means 4 frames 5-8 Mounting part 9 frames 10 volts 11 Bass 12a~12c Joints 13a~13c Arm 20 Handheld Body 21 Cover 30a~30d fingers 31 Inlet 32 Proximal end 33 Female thread section 40 Flange section 90 Through hole 91 Convex part 92 Slope 93 plane H1~H5 mounting holes

Claims

1. Multiple finger-like parts made up of fluid pressure actuators, The frame to which the aforementioned finger portion is attached, A robotic hand having, The base end of each of the aforementioned multiple fingers is attached to the frame, and the distance between the fingertips of the multiple fingers can be adjusted by the operation of the fluid pressure actuator. The frame has a plurality of mounting parts for attaching the base end of the finger, Each of the aforementioned mounting parts has a plurality of mounting holes for fixing the base end of the finger, The mounting holes are arranged in a direction along the operating direction of the fluid pressure actuator fixed to the mounting holes. Robot hand.

2. The robot hand according to claim 1, wherein the mounting portion has a piece that fits detachably into the mounting hole, and the base end of the finger is attached to the piece to fix the finger to the mounting hole.

3. The robot hand according to claim 1 or 2, wherein the piece is a metal fitting having a through hole on the central axis of a cylinder, and has a protrusion around the opening of the through hole that engages with the opening of the mounting hole, and one of the two bottom surfaces of the cylinder has an inclined surface that is inclined with respect to the cylinder axis, and the through hole extends in a direction inclined with respect to a perpendicular line on the surface of the frame.

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