Holding device

Abstract

To provide a hand-held holding device which can delicately open or close arm members with a simple structure.SOLUTION: A hand-held holding device 100 includes: a drive device 1 which moves a friction member 12 frictionally engaged with a drive shaft 11 and the drive shaft 11 relative to each other in an axial direction of the drive shaft 11 by driving a piezoelectric element 14 which is fixed to one end of the drive shaft 11 and converts an electric signal into mechanical vibration; a case 2 which houses the drive device 1; a pair of arm members 3 which is supported at the other end side of the drive shaft 11 by the case 2 and opened or closed by relative movement of the drive shaft 11 and the friction member 12; a battery 4 which is housed in the case 2 at the opposite side of the drive shaft 11 with respect to the piezoelectric element 14; a circuit board 5 which is housed in the case 2 to control driving of the piezoelectric element 14; and an operation switch 6 which is provided on an outer wall of the case 2 and vibrates and stops the piezoelectric element 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a handheld gripping device, and more particularly to an electrically powered handheld gripping device. [Background technology]

[0002] For example, handheld electric tweezers have been proposed as a gripping device that can be used for transporting and assembling microcomponents (see, for example, Patent Document 1). Conventional electric tweezers house a motor, a conversion mechanism, a gripping member having a pair of arms, a switch means, and a battery in a case, and the conversion mechanism converts the rotation of the motor shaft into a reciprocating translational displacement. The gripping member is configured to increase the opening and closing amount of the pair of arms based on the reciprocating translational displacement along the extension direction of the motor shaft, thereby releasing and gripping the object to be gripped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4064299 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional gripping devices require a conversion mechanism that converts the amount of rotation of the motor shaft into a reciprocating translational displacement along the direction in which the motor shaft extends, which results in a complex structure and makes it difficult to open and close the arm section delicately. [Means for solving the problem]

[0005] SUMMARY OF THE INVENTION In order to improve this situation, the present invention has as its technical object to provide a handheld gripping device that has a simple configuration and is capable of delicately opening and closing arm members.

[0006] A handheld gripping device according to one embodiment of the present invention comprises: a drive unit that moves a friction member frictionally engaged with a drive shaft and the drive shaft relative to one another in the axial direction of the drive shaft by driving a piezoelectric element that is fixed to one end of the drive shaft and converts an electrical signal into mechanical vibration; a case that houses the drive unit; a pair of arm members that are supported by the case on the other end of the drive shaft and that open and close by the relative movement of the drive shaft and the friction member; a battery that is housed in the case on the opposite side of the drive shaft from the piezoelectric element; a circuit board that is housed in the case and that controls the driving of the piezoelectric element; and an operation switch that is provided on the outer wall of the case and that vibrates and stops the piezoelectric element.

[0007] The gripping device of the above embodiment has a simple configuration in which a friction member is frictionally engaged with a drive shaft having a piezoelectric element fixed to one end, and the drive shaft and the friction member can be moved relatively in the axial direction of the drive shaft with high resolution by driving the piezoelectric element. Therefore, the gripping device of the embodiment can open and close a pair of arm members with a simple configuration, and can open and close the arm members delicately. Furthermore, because a motor and a reduction gear for rotating the motor shaft are not required, the handheld gripping device can be made lighter, reducing the burden on the user.

[0008] The gripping device of one embodiment may further include at least one of a power switch that turns on and off the supply of power from the battery to the circuit board and an operation setting member that changes the operation mode of the drive device. The operation switch may be provided on the outer wall of the case closer to the arm member, while the power switch and the operation setting member may be provided farther from the arm member than the battery.

[0009] According to this aspect, the operation switch is located near the arm member so that it is easy for a user holding the case with their fingers to operate when using the grip device. Meanwhile, the power switch and operation setting members, which are not operated during use, are located away from the operation switch and battery so that they are less likely to be touched by the user. This prevents the power switch and operation setting members from being switched unintentionally during use, improving operability.

[0010] Furthermore, the gripping device of one embodiment described above may include a cam plate that is connected to the friction member or the drive shaft and moves along the axial direction of the drive shaft due to relative movement between the drive shaft and the friction member, and the arm member may include an arm fulcrum portion rotatably supported on a spindle provided in the case, arm intermediate portions provided on the left and right outside of the fulcrum portion, arm opening / closing portions extending from the intermediate portion toward the tip side of the case, and cam followers that protrude from the intermediate portion and fit into left and right cam grooves provided in the cam plate.

[0011] According to this aspect, the pair of arm members that open and close in response to the relative movement of the drive shaft and the friction member can be formed with a simple structure.

[0012] In addition, according to this aspect, the arm member having the cam follower that fits into the cam groove of the cam plate can be made disposable and can be easily replaced with one having a different tip shape. If the connection between the friction member and the cam plate can be temporarily released when replacing the arm, replacement can be made easier.

[0013] Furthermore, a pair of left and right plate-like elastic members may be provided, the base ends of which are fixed to the case at positions closer to the arm fulcrum than the tip ends of the left and right arm opening / closing sections, and the tip ends of which are spaced apart from each other. The pair of left and right plate-like elastic members may be configured so that the tip ends can be opened and closed by the arm opening / closing sections sliding against mid-way points in the longitudinal direction of the plate-like elastic members in response to opening and closing operations of the arm members.

[0014] According to this aspect, a pair of plate-shaped elastic members whose tip portions can be opened and closed in response to the opening and closing movement of the arm member can be easily replaced, so that the pair of plate-shaped elastic members can be made disposable or can be easily replaced with members having tip portions with different shapes.

[0015] The arm member may further include a slider member connected to the friction member or the drive shaft, slidable along the axial direction of the drive shaft by relative movement between the drive shaft and the friction member, the slider tip end on the side opposite the piezoelectric element being bifurcated, and a pair of left and right plate-like elastic members as the arm member, the base end of which is fixed to the case between the left and right tip ends of the slider member and the tip ends of which are spaced apart from each other. The pair of left and right plate-like elastic members may be configured so that the tip ends of the slider come into sliding contact with longitudinal midpoints of the plate-like elastic members in response to the sliding movement of the slider member, thereby allowing the tip ends to open and close.

[0016] According to this aspect, the slider member slides in response to the relative movement of the drive shaft and the friction member, thereby opening and closing the pair of arm members (plate-shaped elastic members), thereby providing a handheld gripping device with a simple configuration. Furthermore, the pair of arm members can be easily replaced, so the arm members can be made disposable or easily replaced with ones with different tip shapes. [Effects of the Invention]

[0017] The handheld gripping device of the present invention has a simple configuration and allows the arm members to be opened and closed delicately. [Brief explanation of the drawings]

[0018] [Figure 1] 1A and 1B are schematic diagrams showing an embodiment of a gripping device, in which (A) is a plan view and (B) is a vertical cross-sectional view taken along the line AA in (A). [Figure 2] FIG. 2 is a vertical cross-sectional view showing the state in which the cover of the embodiment is removed. [Figure 3]1A is a plan view showing the arm member and its surroundings in this embodiment, FIG. 1B is a perspective view, and FIG. 1C is an exploded perspective view. [Figure 4] 1A and 1B are diagrams for explaining the configuration of a drive device, in which FIG. 1A is a schematic perspective view and FIG. 1B is an exploded perspective view of a frictional engagement portion. [Figure 5] 10A and 10B are schematic diagrams showing another embodiment of the gripping device, in which (A) is a plan view and (B) is a vertical cross-sectional view taken along the line BB in (A). [Figure 6] FIG. 2 is a vertical cross-sectional view showing the state in which the cover of the embodiment is removed. [Figure 7] 1A is a plan view showing the arm member and its surroundings in this embodiment, FIG. 1B is a perspective view, and FIG. 1C is an exploded perspective view. [Figure 8] 10A and 10B are schematic diagrams showing still another embodiment of the gripping device, in which (A) is a plan view and (B) is a vertical cross-sectional view taken along the CC position in (A). [Figure 9] FIG. 2 is a vertical cross-sectional view showing the state in which the cover of the embodiment is removed. [Figure 10] 1A and 1B are diagrams showing the periphery of an arm member of the same embodiment, in which (A) is a plan view and (B) is a perspective view. [Figure 11] FIG. 10 is a conceptual diagram illustrating a gripping device having a function of feeding back a gripping force. [Figure 12] FIG. 2 is an enlarged plan view showing the arm member and its surroundings. [Figure 13] 10 is a graph showing the relationship between the actuator movement amount and the distance between the left and right detection gap portions. [Figure 14] FIG. 1 is a conceptual diagram illustrating a gripping device having a function for monitoring the gripping state of an object to be gripped. [Figure 15] 4 is a timing chart showing an example of a drive pulse waveform. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the gripping device will be described below with reference to the drawings. Fig. 1 is a schematic diagram of the configuration, where (A) is a plan view and (B) is a longitudinal cross-sectional view taken along the line AA in (A). Fig. 2 is a longitudinal cross-sectional view showing the state with the cover removed. Fig. 3 is a diagram showing the arm member and cam plate, where (A) is a plan view, (B) is a perspective view, and (C) is an exploded perspective view. Fig. 4 is a diagram for explaining the configuration of the drive device, where (A) is a schematic perspective view and (B) is a perspective view showing the frictional engagement portion in isolation.

[0020] In the following description, terms indicating specific directions or positions (such as "left and right," "front and back," and "up and down") are used as necessary, but these terms are used for convenience of explanation and do not limit the technical scope of the present invention. In this embodiment, the direction in which the drive shaft of the drive device extends is the front and back direction, the side on which the arm member is located is the front side, and the side on which the circuit board is located is the rear side. Furthermore, the direction in which the tip of the arm member opens and closes is the left and right direction.

[0021] The gripping device 100 has a drive unit 1, a case 2 that houses the drive unit 1, a pair of arm members 3 supported on the front end side of the case 2, a battery 4 and a circuit board 5 housed within the case 2, and an operation switch 6 provided on the outer wall of the case 2. The drive unit 1 moves a friction member 12 that is frictionally engaged with the drive shaft 11 and the drive shaft 11 relative to each other in the axial direction of the drive shaft 11 by driving a piezoelectric element 14 that is fixed to one end (the rear end in this embodiment) of the drive shaft 11 and converts an electrical signal into mechanical vibration. Although not shown in the figure, the piezoelectric element 14 is connected to the circuit board 5 via electrical wiring.

[0022] The pair of arm members 3 are supported by the case 2 at the other end (front end) of the drive shaft 11, and open and close by the relative movement of the drive shaft 11 and friction member 12. The battery 4 is housed in the case 2 on the opposite side of the drive shaft 11 with respect to the piezoelectric element 14. The circuit board 5 is for controlling the driving of the piezoelectric element 14. The operation switch 6 is for oscillating and stopping the piezoelectric element 14, which is driven by power from the battery 4.

[0023] The drive unit 1 of the gripping device 100 can move the drive shaft 11 and the friction member 12 relatively in the axial direction of the drive shaft 11 with high resolution by driving the piezoelectric element 14. Furthermore, the drive unit 1 can be formed with a simple configuration in which the friction member 12 is frictionally engaged with the drive shaft 11, which has the piezoelectric element 14 fixed to one end. Therefore, the gripping device 100 can open and close the pair of arm members 3 with a simple mechanism, and can open and close the arm members 3 delicately. Furthermore, because a motor for rotating the motor shaft is not required, the handheld gripping device 100 can be made lighter, reducing the burden on the user.

[0024] Next, each part will be described in detail. <Driver configuration> 1 to 4, the drive device 1 includes a drive shaft 11, a friction member 12 that frictionally engages with the drive shaft 11, and a piezoelectric element 14 that is fixed to the end of the drive shaft 11 and converts an electrical signal into mechanical vibration. The piezoelectric element 14 is, for example, a laminated type in which piezoelectric materials are laminated in the axial direction of the drive shaft 11. The drive device 1 is configured so that the drive shaft 11 and the friction member 12 are moved relative to each other in the axial direction of the drive shaft 11 by driving the piezoelectric element 14.

[0025] The drive unit 1 is a device that converts electrical energy into mechanical work using a piezoelectric element 14. In the drive unit 1, a single pulse or continuous pulse of a sawtooth wave is applied to the piezoelectric element 14 under the control of the circuit board 5, thereby changing the state of the contact surface between the drive shaft 11 and the friction member 12 between a stuck state (stick) and a sliding state (slip), thereby moving the drive shaft 11 and the friction member 12 relative to each other.

[0026] The drive shaft 11 has a substantially rectangular cross section and includes four axial planes 11a extending in the axial direction of the drive shaft 11. The drive shaft 11 is formed, for example, from a carbon fiber reinforced plastic (CFRP) in a substantially rectangular parallelepiped shape. The corners of the drive shaft 11 extending in the axial direction may have a linear or rounded chamfered shape.

[0027] The drive unit 1 includes four friction members 12, each provided on one of the four axial planes 11a. Each friction member 12 has a friction plane 12a that is in surface contact with the axial plane 11a. In this embodiment, each friction member 12 is formed of a metal or carbon fiber reinforced resin plate that is long in the axial direction of the drive shaft 11.

[0028] The upper and lower friction members 12 have widths slightly smaller than the surface widths of the upper and lower axial planes 11a (widths perpendicular to the axial direction). The left and right friction members 12 have widths slightly larger than the surface widths of the left and right axial planes 11a, and the left and right friction members 12 have lengths longer in the axial direction than the upper and lower friction members 12. The friction members 12 are arranged so as not to come into contact with each other.

[0029] As shown in Fig. 4, the friction member 12 is pressed toward the axial plane 11a by the elastic force of the elastic member 13. As a result, the axial plane 11a and the friction plane 12a are frictionally engaged with each other. The friction member 12 and the elastic member 13 constitute a friction engagement unit 10. When the piezoelectric element 14 is driven, the friction engagement unit 10 and the drive shaft 11 move relatively in the axial direction of the drive shaft 11. Note that the elastic member 13 is not shown in Figs. 1 to 3.

[0030] The width of the friction member 12 may be the same as the width of the axial plane 11a. In this case, it is preferable that each friction member 12 does not interfere with the surface contact between the friction plane 12a of another friction member 12 and the axial plane 11a, and for example, it is preferable that adjacent friction members 12 do not come into contact with each other.

[0031] In this embodiment, the elastic member 13 is made of an annular elastic body that restrains the four friction members 12 from the outer periphery of the drive shaft 11. The four friction members 12 are provided so as to be movable as a unit by the elastic member 13. The elastic member 13 is made of an annular rubber elastic body made of, for example, silicone rubber.

[0032] The drive unit 1 of this embodiment is equipped with six elastic members 13. Each elastic member 13 is formed of a rubber band whose inner diameter is smaller than the outer periphery of the four friction members 12 attached to the drive shaft 11. As can be seen from FIG. 4(B), the elastic members 13 are attached by applying force to expand the diameter of the elastic members 13, inserting the drive shaft 11 and the friction members 12 into the elastic members 13, and then releasing the force expanding the elastic members 13 to reduce their diameter. This causes the elastic members 13 to restrain the friction members 12 to the drive shaft 11. Note that the elastic members 13 may also be attached by inserting the friction members 12 between the elastic members 13 attached to the drive shaft 11 and the axial plane 11a.

[0033] The six elastic members 13 are lined up in the axial direction of the drive shaft 11 without overlapping each other, and restrain the four friction members 12 to the drive shaft 11. Note that these elastic members 13 may overlap each other while restraining the friction members 12 to the drive shaft 11. The number of elastic members 13 may be one or more. Alternatively, one or more annular rubber elastic bodies with a large inner diameter may be wound twice, three or more times around the outer peripheries of the four friction members 12 to restrain the four friction members 12 to the drive shaft 11.

[0034] In the drive unit 1, the four friction members 12 that frictionally engage with the four axial planes 11a of the drive shaft 11 are individually provided so as not to come into contact with one another, and this allows the elastic members 13 to absorb any external shape accuracy of the drive shaft 11 (machining error in the angle formed by adjacent axial planes 11a). This allows the friction planes 12a of the friction members 12 to be reliably brought into surface contact with each axial plane 11a, stabilizing the friction force between the drive shaft 11 and the friction members 12 and suppressing variations in the drive characteristics of the drive unit 1. Furthermore, since the drive unit 1 does not require high-precision machining of the drive shaft 11 and the friction members 12, manufacturing costs can be reduced.

[0035] Furthermore, in the drive unit 1, the elastic member 13 is composed of an annular elastic body that restrains the four friction members 12 from the outer periphery of the drive shaft 11. This allows the drive unit 1 to frictionally engage the four friction members 12 with the drive shaft 11 with a simple configuration and hold them so that they can move integrally. Therefore, the drive unit 1 can reduce manufacturing costs and weight. Furthermore, because the elastic members 13 are attached to the friction members 12 by their own restoring force, the friction members 12 can be frictionally engaged with the drive shaft 11 without any member to support the elastic members 13, thereby achieving reduced manufacturing costs and weight.

[0036] <Case configuration> 1 and 2, the case 2 is made of, for example, plastic, has a generally cylindrical shape tapered toward the front end, and includes, in order from the front end, an arm storage section 21, a drive unit storage section 22, a battery storage section 23, and a circuit board storage section 24. The case 2 can be separated into an upper and lower section, and includes a lower case main body 20 and an upper arm cover 21a, a drive unit cover 22a, a battery cover 23a, and a circuit board cover 24a.

[0037] 2, the drive unit cover 22a and the circuit board cover 24a are fixed to the case body 20 with, for example, adhesive or screws. The arm cover 21a and the battery cover 23a are detachably fixed to the case body 20 with, for example, locking claws or screws. This makes it possible to replace the arm member 3 and the battery 4.

[0038] A pair of upper and lower bosses 25 are provided in the arm storage section 21 of the case 2 to support an arm support shaft 30 for rotatably supporting the pair of arm members 3. The bosses 25 are provided on the case main body 20 and the arm cover 21a, respectively. The upper and lower bosses 25 support the arm support shaft 30 so that it extends in the vertical direction.

[0039] A drive unit support base 26 for supporting the drive unit 1 is provided in the drive unit storage section 22. The drive unit support base 26 is disposed in a rearward position of the drive unit storage section 22, and is provided in the shape of a generally rectangular parallelepiped that is long in the front-to-rear direction and protrudes upward from the bottom surface of the case body 20. The piezoelectric element 14 of the drive unit 1 is fixed to the upper surface of the drive unit storage section 22, for example with an adhesive, such that the drive shaft 11 of the drive unit 1 and the piezoelectric element 14 are oriented along the center line of the case 2.

[0040] Of the friction members 12 of the drive unit 1, the left and right friction members 12 extend from the drive unit storage section 22 to the arm storage section 21. The front ends of the left and right friction members 12 are disposed in the arm storage section 21.

[0041] A pair of front and rear partitions 27 are provided between the drive unit housing 22 and the battery housing 23, and between the battery housing 23 and the circuit board housing 24. The partitions 27 are formed by substantially disk-shaped partition walls that stand upright from the inner wall of the case body 20. Although not shown, the battery housing 23 is provided with terminal members for the battery on each of the front and rear partitions 27.

[0042] A board support stand 28 that supports the circuit board 5 is provided in the circuit board storage section 24. The board support stand 28 is provided in a generally rectangular parallelepiped shape that is long in the front-to-rear direction and protrudes upward from the bottom surface of the case body 20. The circuit board 5 is supported on the upper surface of the board support stand 28. Note that the support structure for the circuit board 5 is not particularly limited, and may be configured such that the circuit board 5 is screwed to a plurality of screw bosses, for example.

[0043] 1(A), an operation switch 6 for vibrating and stopping the piezoelectric element 14 of the drive unit 1 is provided near the front end of the outer wall of the case 2. In this embodiment, the operation switch 6 is provided on the left side surface of the case 2, at the boundary between the drive unit cover 22a and the case main body 20.

[0044] A power switch 7A and an operation setting member 7B are provided near the rear end of the outer wall of the case 2. The power switch 7A and the operation setting member 7B are connected to the circuit board 5 via electrical wiring. The power switch 7A is used to turn on and off the supply of power from the battery 4 to the circuit board 5. The operation setting member 7B is used to switch the strength of the driving force of the piezoelectric element 14. The circuit board 5 switches the strength of the driving force of the piezoelectric element 14 by changing, for example, the waveform of the voltage applied to the piezoelectric element 14, the magnitude of the applied voltage, or the magnitude of the current supplied to the piezoelectric element 14 in response to switching of the operation setting member 7B. In this embodiment, the power switch 7A and the operation setting member 7B are provided near the rear end of the underside of the case main body 20.

[0045] The operation setting member 7B may be configured to change the operation mode of the drive device 1, and may be, for example, a two-stage or multi-stage (or dial-type) selector switch or a push button switch. Examples of changes in the operation mode of the drive device 1 include changing the gripping force strength (two or more stages), switching the speed (two or more stages), switching whether to stop the drive device 1 when the change in the detection signal of a position detection device 204 (see FIG. 11 ) such as an encoder becomes small, and switching the gripping force feedback function on and off. The operation setting member 7B may also be configured to change the operation mode of the operation switch 6. Examples of changes in the operation mode of the operation switch 6 include switching between a mode in which the arm member 3 is opened and closed each time the operation switch 6 is pressed, and a mode in which the arm member 3 is repeatedly closed when the operation switch 6 is pressed for a short time and opens when the operation switch 6 is pressed for a long time. In addition, the operating mode of the operation switch 6 can be changed between a mode in which the opening or closing operation activated by pressing the operation switch 6 is limited to a predetermined time, and a mode in which the opening or closing operation continues as long as the operation switch 6 is pressed.

[0046] Thus, on the outer wall of the case 2, the operation switch 6 is located near the front end of the case 2 (near the arm member 3), while the power switch 7A and the operation setting member 7B are located farther from the arm member 3 than the battery 4 (in this embodiment, nearer the rear end of the case 2). In other words, the operation switch 6 is located near the arm member 3 where it is easy for a user holding the case 2 with their fingers to operate. On the other hand, the power switch 7A and the operation setting member 7B, which are not operated during use, are located away from the arm member 3 where they are unlikely to be reached by the hand during use. This prevents the power switch 7A and the operation setting member 7B from being unintentionally switched during use, improving operability.

[0047] <Arm component configuration> As shown in Figures 1 to 3, a pair of left and right arm members 3 are supported on arm support shafts 30 extending in the vertical direction so as to be rotatable independently of each other. The left and right arm members 3 are connected to a cam plate 9 arranged behind the arm support shafts 30. The cam plate 9 is connected to the front end of a friction member 12, and is provided so as to be slidable along the axial direction of the drive shaft 11 by the relative movement between the drive shaft 11 and the friction member 12.

[0048] Each arm member 3 comprises a cylindrical arm fulcrum portion 31 rotatably supported on an arm support shaft 30, an arm intermediate portion 32 provided on the left and right outer sides of the arm fulcrum portion 31, an arm opening / closing portion 33 extending from the arm intermediate portion 32 toward the tip side of the case 2, and a cam follower 34 protruding from the arm intermediate portion 32 and fitting into left and right cam grooves 91 provided in the cam plate 9.

[0049] In this embodiment, the left and right arm members 3 have the same shape. The left and right arm members 3 are arranged upside down and the arm fulcrum portions 31 of both arm members 3 are stacked one on top of the other and inserted into the arm support shaft 30, whereby the tip ends of the arm opening / closing portions 33 are rotatably supported on the arm support shaft 30 so as to be able to move toward and away from each other. In the left arm member 3, the arm intermediate portion 32 extends leftward from the arm fulcrum portion 31, and the cam follower 34 protrudes upward from the top surface of the arm intermediate portion 32. In the right arm member 3, the arm intermediate portion 32 extends rightward from the arm fulcrum portion 31, and the cam follower 34 protrudes downward from the bottom surface of the arm intermediate portion 32.

[0050] The cam plate 9 has a generally box-shaped cam body 92 and left and right cam arms 93 that protrude forward from the front of the cam body 92. The cam body 92 has a generally upward U-shape with an open top and front and rear faces. The tip of the friction member 12 is connected to the inside of the cam body 92 by, for example, adhesive or screws.

[0051] The cam arm 93 has a generally L-shaped configuration in plan view, with its tip extending outward to the left and right. A cam groove 91 extending in the left-right direction is formed at the tip of the cam arm 93. In this embodiment, the left and right outer ends of the cam groove 91 open to the left and right outer surfaces of the cam arm 93. The cam groove 91 extending in the left-right direction has a groove width slightly larger than that of the cam follower 34 of the arm member 3, and the cam follower 34 is provided to be slidable in the left-right direction within the cam groove 91 of the cam plate 9 that moves in the front-rear direction.

[0052] Next, we will explain the opening and closing operation of the arm member 3. As shown in Figure 3, when the tip ends of the arm opening and closing parts 33 of both arm members 3 are closed (in contact), the cam followers 34 and cam grooves 91 of the arm members 3 are located on the left and right outer sides of the arm support shaft 30.

[0053] When a user presses the operation switch 6, the circuit board 5 vibrates the piezoelectric element 14 so that the friction member 12, which is frictionally engaged with the drive shaft 11 of the drive device 1, moves rearward (toward the piezoelectric element 14). The circuit board 5 vibrates the piezoelectric element 14 while the operation switch 6 is being pressed.

[0054] When the friction member 12 moves rearward, the cam plate 9 fixed to the front end of the friction member 12 also moves rearward. Accordingly, the cam follower 34 engaged with the cam groove 91 moves rearward around the arm spindle 30 as its rotation center while moving inward to the left and right within the cam groove 91. Then, the arm intermediate portion 32 rotates rearward around the arm spindle 30 as its rotation center. As a result, the tip ends of the left and right arm opening / closing portions 33 move outward to the left and right, respectively, and the left and right arm members 3 are opened.

[0055] When the pressing of the operation switch 6 is released, the circuit board 5 stops the piezoelectric element 14 that is driving the vibration so as to open the arm member 3. The user can adjust the degree to which the arm member 3 opens by adjusting the time for which the operation switch 6 is pressed.

[0056] When the user presses the operation switch 6 again after the arm members 3 have opened, the circuit board 5 vibrates and drives the piezoelectric element 14 so that the arm members 3 close. At this time, the friction member 12 and the cam plate 9 move forward, and the left and right arm intermediate portions 32 each rotate forward about the arm support shaft 30, causing the tips of the left and right arm opening / closing portions 33 to move inward to the left and right. In other words, the left and right arm members 3 close. As a result, an object to be grasped located between the tips of the left and right arm opening / closing portions 33 can be grasped by the left and right arm members 3.

[0057] When the operation switch 6 is released, the circuit board 5 stops the vibration drive of the piezoelectric element 14. Even if the drive of the piezoelectric element 14 is stopped after the left and right arm members 3 have grasped the object to be grasped, the friction member 12, which is in frictional engagement with the drive shaft 11, does not move, so the movement of the cam plate 9 and the rotation of both arm members 3 are restricted, and the state in which the object to be grasped is maintained.

[0058] The user can adjust the degree to which the arm members 3 are closed by adjusting the time that the operation switch 6 is pressed. The circuit board 5 controls the drive of the piezoelectric element 14 so that the arm members 3 alternately open and close each time the operation switch 6 is pressed and released. Note that although the operation switch 6 has been described as a momentary type (self-resetting type) that is on only when pressed, the type of operation switch 6 is not particularly limited, and it may be, for example, an alternate type (self-holding type) push button switch.

[0059] As shown in Fig. 2, in the gripping device 100, the arm cover 21a of the case 2 is provided to be removable. Both arm members 3 can be removed from the case 2 by pulling the arm support shaft 30 out from at least the lower boss portion 25 of the upper and lower boss portions 25. This makes it easy to replace the arm member 3 when it is deformed or damaged, or when it is desired to replace it with an arm member 3 having a different shape or rigidity. In this embodiment, the left and right arm members 3 have the same shape, but it is also possible to attach a left arm member 3 and a right arm member 3.

[0060] Next, another embodiment of the gripping device 100 will be described with reference to Figures 5 to 7. In the description of this embodiment, the same components as those in the above-described embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0061] In the gripping device 100 of this embodiment, the arm storage section 21 of the case 2 is configured to store the entire arm member 3. The arm member 3 of this embodiment has a different shape from the arm member 3 of the above embodiment described with reference to Figures 1 to 4, but is equipped with an arm fulcrum section 31, an arm intermediate section 32, an arm opening / closing section 33, and a cam follower 34, and has the same basic configuration as the arm member 3 of the above embodiment.

[0062] A tweezers-shaped gripping member 8 having a pair of left and right plate-shaped elastic members 81 is supported in the arm storage section 21. The gripping member 8 is made of an elastic metal or resin plate formed into a substantially V-shape, and is equipped with a pair of left and right plate-shaped elastic members 81 with tip ends spaced apart from each other, and a connecting section 82 that connects the base ends of the left and right plate-shaped elastic members 81. The gripping member 8 is configured so that when force is applied to the plate-shaped elastic members 81 from the left and right outside, portions of the plate-shaped elastic members 81 near the connecting section 82 elastically deform, allowing the tip ends of the plate-shaped elastic members 81 to come into contact with each other.

[0063] The arm storage section 21 is provided with a pair of upper and lower bosses 29 that support the connecting portion 82 of the gripping member 8. The bosses 29 are provided on both the case body 20 and the arm cover 21a. The upper and lower bosses 29 support the gripping member 8 by sandwiching the connecting portion 82 between the upper and lower parts. The upper and lower bosses 29 also support a pin member 80 that is disposed between the base ends of the left and right plate-shaped elastic members 81 so as to extend in the vertical direction. The pin member 80 is disposed in front of the connecting portion 82 and prevents the gripping member 8 from coming off.

[0064] The gripping member 8 is in a position in which the tip end of the plate-shaped elastic member 81 extends forward from the front end opening 2a of the case 2, and the portion of the plate-shaped elastic member 81 near the base end and the connecting portion 82 are disposed between the left and right arm opening / closing portions 33. In this embodiment, the gripping member 8 is supported by the case 2 in a state in which the midpoint in the front-to-rear direction of the outer surface of the plate-shaped elastic member 81 abuts against the left and right ends of the front end opening 2a, and the portion of the plate-shaped elastic member 81 near the connecting portion 82 is elastically deformed.

[0065] 5(A) and 7, when the tip ends of the plate-shaped elastic members 81 of the gripping member 8 are in an open state, the tip ends of the arm opening / closing sections 33 of both arm members 3 are in contact with or disposed close to the left and right outer surfaces of the plate-shaped elastic members 81. In other words, the tip ends of the arm opening / closing sections 33 of both arm members 3 are in an open state. The pair of left and right plate-shaped elastic members 81 are arranged so that the tip ends of the plate-shaped elastic members 81 can be opened and closed by the arm opening / closing sections 33 slidingly contacting the midpoints of the plate-shaped elastic members 81 in the longitudinal direction in response to the opening and closing movement of the arm members 3.

[0066] Next, the opening and closing operation of the gripping member 8 will be described. When the user presses the operation switch 6, the circuit board 5 vibrates the piezoelectric element 14 so that the friction member 12 of the drive device 1 moves forward (towards the arm member 3). The circuit board 5 vibrates the piezoelectric element 14 while the operation switch 6 is being pressed.

[0067] When the friction member 12 moves forward, the cam plate 9 also moves forward, and the cam follower 34 engaged with the cam groove 91 moves forward around the arm support shaft 30 as its rotation center. Then, the arm intermediate portion 32 rotates forward around the arm support shaft 30 as its rotation center. As a result, the tips of the left and right arm opening / closing portions 33 move inward to the left and right, respectively, and urge the left and right outer surfaces of the plate-shaped elastic members 81 inward to the left and right. The plate-shaped elastic members 81 elastically deform inward to the left and right at the portions closer to the connecting portion 82 than the points of contact with the arm opening / closing portions 33, and an object to be grasped between the tips of the left and right plate-shaped elastic members 81 is grasped, or the tips of the left and right plate-shaped elastic members 81 are closed.

[0068] When the operation switch 6 is released from the depressed state, the circuit board 5 stops the piezoelectric element 14. Even when the driving of the piezoelectric element 14 is stopped, the friction member 12, which is in frictional engagement with the drive shaft 11, does not move, so the movement of the cam plate 9 and the rotation of both arm members 3 are restricted, and the opening movement of the gripping members 8 is restricted. This makes it possible to maintain the state in which the object to be gripped is gripped between the tips of the left and right plate-shaped elastic members 81.

[0069] When the user presses the operation switch 6 again after the gripping member 8 and arm member 3 have closed, the circuit board 5 vibrates and drives the piezoelectric element 14 so that the arm member 3 opens. This causes the friction member 12 and cam plate 9 to move backward, and the left and right arm opening / closing portions 33 open. Then, the biasing force of the arm opening / closing portions 33 on the plate-shaped elastic members 81 weakens, and the left and right plate-shaped elastic members 81 open in directions away from each other due to their elastic restoring force.

[0070] When the pressing operation of the operation switch 6 is released, the circuit board 5 stops the vibration driving of the piezoelectric element 14. When the plate-shaped elastic member 81 is not in contact with the left or right end of the front-end opening 2a of the case 2, the friction member 12, which is frictionally engaged with the drive shaft 11, does not move, so the movement of the cam plate 9 and the rotation of both arm members 3 are restricted, and the degree of opening of the tips of the left and right plate-shaped elastic members 81 is maintained. The user can adjust the degree of opening of the arm members 3 by adjusting the pressing operation time of the operation switch 6. As in the above embodiment, the circuit board 5 controls the driving of the piezoelectric element 14 so that the opening and closing operations of both arm members 3 are alternately performed each time the operation switch 6 is pressed and released.

[0071] 6, the arm cover 21a of the case 2 is removable, so that the gripping member 8 can be easily replaced. For example, the gripping member 8 can be made disposable, or the tip of the plate-shaped elastic member 81 can be easily replaced with one having a different shape.

[0072] In this embodiment, the pair of left and right plate-shaped elastic members 81 are connected by the connecting portion 82, but the left and right plate-shaped elastic members 81 may be separate from each other. In this case, the base ends of the left and right plate-shaped elastic members 81 are respectively fixed to the case 2. For example, the case 2 may have portions (for example, slits) for fixing the base ends of the left and right plate-shaped elastic members 81, respectively.

[0073] Next, still another embodiment of the gripping device 100 will be described with reference to Figures 8 to 10. In the description of this embodiment, the same components as those in the above-described embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0074] Unlike the above-described embodiments, the gripping device 100 of this embodiment does not include an arm member 3, a cam plate 9, and an arm support shaft 30 (see FIG. 1, etc.). In this embodiment, a pair of left and right plate-shaped elastic members 81 function as arm members. In this embodiment, similar to the above-described embodiments described with reference to FIGS. 5 to 7, the left and right plate-shaped elastic members 81 together with a connecting portion 82 form a tweezers-shaped gripping member 8.

[0075] The case 2 is provided with boss portions 19 that support the base ends of the left and right plate-shaped elastic members 81 at positions near the drive device storage portion 22 within the arm storage portion 21. The boss portions 19 are provided on the case main body 20 and the arm cover 21a. The upper and lower boss portions 29 sandwich the base ends of the left and right plate-shaped elastic members 81 and the connecting portion 82 from above and below, and support the base end of the gripping member 8. The upper and lower boss portions 29 also support pin members 80 that are disposed in front of the connecting portion 82 and prevent the gripping member 8 from coming off, so as to extend in the vertical direction.

[0076] The gripping member 8 is supported by the case 2 with the tip ends of the plate-shaped elastic members 81 extending forward from the front-end opening 2a of the case 2. The left and right plate-shaped elastic members 81 are provided with inclined surface portions 81a at locations near the base ends that are inclined outward to the left and right from the base end side to the tip end side. The inclined surface portions 81a are arranged inside the arm storage section 21.

[0077] Of the friction members 12 of the drive unit 1, the tip ends of the left and right friction members 12 are disposed in the arm storage section 21. The tip ends of the left and right friction members 12 are disposed in contact with or close to the left and right outer surfaces of the inclined surface sections 81a of the left and right plate-shaped elastic members 81. In other words, the base ends of the pair of left and right plate-shaped elastic members 81, whose tip ends are spaced apart from each other, are fixed to the case 2 between the tip ends of the left and right friction members 12.

[0078] In this embodiment, the left and right friction members 12 are slidable along the axial direction of the drive shaft 11 by relative movement between the drive shaft 11 and the friction members 12, and constitute slider members whose slider tip portions (the tip portions of the left and right friction members 12) on the side opposite the piezoelectric element 14 are bifurcated to the left and right. Note that a slider member whose slider tip portion is bifurcated to the left and right may be formed separately from the friction member 12, and the slider member may be connected to the tip side of the friction member 12.

[0079] Next, we will explain the opening and closing operation of the gripping member 8. When the tip ends of the plate-shaped elastic members 81 of the gripping member 8 are open, as shown in Fig. 8(A), the tip ends of the left and right friction members 12 are in contact with or adjacent to the portions of the inclined surface portions 81a of the plate-shaped elastic members 81 near the base ends.

[0080] When a user presses the operation switch 6, the circuit board 5 vibrates and drives the piezoelectric element 14 so that the friction member 12 of the drive device 1 moves forward (toward the tip end of the plate-shaped elastic member 81). The circuit board 5 vibrates and drives the piezoelectric element 14 while the operation switch 6 is being pressed.

[0081] When the friction members 12 move forward, the tip ends of the left and right friction members 12 located in the arm storage section 21 move forward while sliding against the inclined surface portions 81a of the plate-shaped elastic members 81. The inclined surface portions 81a are urged inward to the left and right by the tip ends of the left and right friction members 12. The plate-shaped elastic members 81 elastically deform inward to the left and right at the portions of the plate-shaped elastic members 81 closer to the connecting portion 82 than the points of contact with the tip ends of the friction members 12, and an object to be grasped located between the tip ends of the left and right plate-shaped elastic members 81 is grasped, or the tip ends of the left and right plate-shaped elastic members 81 are closed.

[0082] When the operation switch 6 is released from the depressed state, the circuit board 5 stops the piezoelectric element 14. Even when the driving of the piezoelectric element 14 is stopped, the friction member 12, which is in frictional engagement with the drive shaft 11, does not move, so the rearward movement of the tip of the friction member 12 abutting against the inclined surface portion 81a is restricted, and the opening movement of the gripping members 8 is restricted. This makes it possible to maintain the state in which the object to be gripped is held between the tip ends of the left and right plate-shaped elastic members 81.

[0083] When the user presses the operation switch 6 again after the gripping members 8 have closed, the circuit board 5 vibrates the piezoelectric element 14 to open the gripping members 8. As a result, the tips of the left and right friction members 12 move rearward while sliding against the inclined surface 81a, and the contact points between the tips of the friction members 12 and the inclined surface 81a move rearward. Accordingly, the left and right plate-shaped elastic members 81 open in directions away from each other due to their elastic restoring force.

[0084] When the pressing operation of the operation switch 6 is released, the circuit board 5 stops the vibration driving of the piezoelectric element 14. When the plate-shaped elastic member 81 is not in contact with the left or right ends of the front-end opening 2a of the case 2, the friction member 12, which is in frictional engagement with the drive shaft 11, does not move, and therefore the degree of opening of the tips of the left and right plate-shaped elastic members 81 is maintained. The circuit board 5 controls the driving of the piezoelectric element 14 so that the opening and closing operations of the plate-shaped elastic members 81 are alternately performed each time the operation switch 6 is pressed and released.

[0085] The gripping device 100 of this embodiment can provide a handheld gripping device with a simple configuration because the friction member 12 (slider member) slides in response to the relative movement of the drive shaft 11 and the friction member 12, allowing the pair of plate-shaped elastic members 81 (arm members) to be opened and closed. Also, as shown in Fig. 9, in this embodiment, the arm cover 21a of the case 2 is removable, so that the gripping members 8 having the left and right plate-shaped elastic members 81 can be easily replaced. The left and right plate-shaped elastic members 81 may be separate from each other.

[0086] Incidentally, the drive unit 1 of the gripping device 100 of the above embodiment can control the relative movement between the drive shaft 11 and the friction member 12 with high resolution, for example, on the order of several tens of nanometers (nm), and therefore can delicately control the gripping force of the arm member. Utilizing this characteristic, it is possible to grip the object to be gripped with an appropriate force while feeding back the gripping force on the object to be gripped.

[0087] Fig. 11 is a conceptual diagram for explaining a gripping device equipped with a function for feeding back a gripping force, where (A) is a plan view and (B) is a longitudinal cross-sectional view showing the control unit. Fig. 12 is a plan view showing an enlarged view of the periphery of the arm member 3. The same components as those in the above embodiment are given the same reference numerals, and their description will be omitted.

[0088] The gripping device 200 includes a drive unit 1 that moves a drive shaft 11, a friction member 12, and the drive shaft 11 relative to one another in the axial direction, and a pair of arm members 3 that open and close due to the relative movement of the drive shaft 11 and the friction member 12. Both arm members 3 are connected to the friction member 12 via a cam plate 9. The drive unit 1 has the same structure as that shown in FIG. 4, and includes the drive shaft 11, a friction engagement unit 10 having the friction member 12 and an elastic member 13, and a piezoelectric element 14.

[0089] 3, and includes an arm fulcrum portion 31, an arm intermediate portion 32, an arm opening / closing portion 33, and a cam follower 34. The arm opening / closing portion 33 includes an arm tip portion 33a that grips the object to be gripped, a detection gap portion 33b connected to the base end side of the arm tip portion 33a, and an arm flexure portion 33c provided between the detection gap portion 33b and the arm intermediate portion 32.

[0090] The left and right arm members 3 are formed so that the detection gaps 33b are spaced apart while the arm tip ends 33a are in contact with each other. The arm flexure portion 33c is provided so as to be elastically deformable such that the longitudinal center portion curves inward to the left and right when the piezoelectric element 14 is driven so as to move the friction member 12 further toward the arm member 3 after the object to be gripped is gripped between the left and right arm tip ends 33a.

[0091] The arm support shaft 30, which rotatably supports both arm members 3, is supported by a machine base 201 and a camera base 201a. The machine base 201 also supports the piezoelectric element 14 of the drive unit 1. The camera base 201a supports an imaging device 203 for measuring the distance between the detection gaps 33b of both arm members 3. The imaging device 203 is positioned above the left and right detection gaps 33b when the left and right arm members 3 are closed. Figure 12 shows an example of the camera field of view F of the imaging device 203.

[0092] A position detection device 204 for detecting the front-rear position of the friction engagement unit 10 is disposed below the friction engagement unit 10. The position detection device 204 is configured by, for example, an encoder, and is supported by the machine base 201 below the friction engagement unit 10.

[0093] The gripping device 200 includes a control unit 205 that controls the operation of the piezoelectric element 14. The control unit 205 is also electrically connected to the imaging device 203 and the position detection device 204, and acquires image information of the left and right detection gaps 33b and position information of the friction engagement unit 10. When an object to be gripped is gripped between the left and right arm tips 33a, the control unit 205 calculates the gripping force of the left and right arm members 3 based on the image information captured by the imaging device 203 and the position information of the friction engagement unit 10 detected by the position detection device 204.

[0094] 13 is a graph showing the relationship between the actuator movement amount determined by the position of the friction engagement unit 10 and the distance between the left and right detection gaps 33b. The horizontal axis represents the actuator movement amount, and the vertical axis represents the gap distance. The units of both axes are, for example, μm (micrometers).

[0095] In the graph of Figure 13, characteristic curve A represents the unloaded characteristic curve when no load is applied to arm opening / closing unit 33. Characteristic curve B represents the characteristic curve when an object to be grasped is grasped between left and right arm tips 33a. Note that characteristic curve B is a curve that differs depending on the softness of the object to be grasped. Point P where characteristic curves A and B intersect represents the start point of grasping.

[0096] When an object to be grasped is grasped between the left and right arm tip portions 33a, the arm flexure portion 33c elastically deforms, and the distance between the left and right detection gap portions 33b relative to the amount of movement of the friction engagement unit 10 shifts upward from the no-load characteristic curve A, becoming a curve like the object-grasping characteristic curve B starting from the grasping starting point P.

[0097] The control unit 205 calculates the deviation G of the gap distance from the no-load characteristic curve A at a certain actuator movement amount, and converts the deviation G into a gripping force. The greater the deviation G, the greater the gripping force.

[0098] The control unit 205 can monitor the gripping force of the left and right arm members 3 by monitoring the deviation G of the gap distance from the no-load characteristic curve A. When the control unit 205 detects the deviation G corresponding to the desired gripping force, it stops driving the piezoelectric element 14 or reduces the force generated by the drive unit. The control unit 205 may also control the drive unit 1 to increase the generated force for a short period of time to ensure a secure grip before reducing the generated force. This allows the object to be gripped with the desired gripping force. Because the drive unit 1 can control the relative movement between the friction engagement unit 10 (friction member 12) and the drive shaft 11 with high resolution, it is also possible to control the drive unit 1 to grip the object with, for example, a very weak but precise gripping force.

[0099] It is also possible to observe only the deflection shape of the arm member 3 and convert it into a gripping force without using the actuator movement amount information. In this case, an image processing device is required to analyze the deflection shape of the arm member 3 (for example, arm flexure 33c), but there is an advantage in that it does not require a position detection device 204 such as an encoder for acquiring actuator movement information.

[0100] Next, another method for monitoring the gripping state of the object to be gripped by the arm member 3 will be described. FIG. 14 is a conceptual diagram for explaining a gripping device equipped with a grip detection function. (B) is a longitudinal sectional view showing the control unit. Components similar to those in the above embodiment are given the same reference numerals, and their description will be omitted.

[0101] The gripping device 200 of this embodiment includes a piezoelectric element 206 for grip detection attached to the friction member 12 of the friction engagement unit 10, and a weight member 207 fixed to the piezoelectric element 206. The weight member 207 is attached to one end of the piezoelectric element 206 at a distance from the friction member 12.

[0102] The piezoelectric element 206 for grip detection is configured, for example, as a laminated type in which piezoelectric materials are laminated in the axial direction of the drive shaft 11 and the friction member 12. The piezoelectric element 206 is provided so as to be able to detect minute vibrations in the axial direction of the friction member 12 by converting the movement of the weight member 207 that receives vibrations of the friction member 12 into an electric signal. The control unit 205 monitors the electric signal of the piezoelectric element 206.

[0103] When an object to be grasped is grasped between the left and right arm members 3, the piezoelectric element 14 is driven to vibrate to move the drive shaft 11 and the friction member 12 relative to each other in order to close both open arm members 3. In this embodiment, the piezoelectric element 14 is driven to vibrate so as to move the friction member 12 forward. The control unit 205 monitors the electrical signal of the piezoelectric element 206.

[0104] When both arm members 3 start to grasp the object to be grasped, friction member 12 enters a state of free sliding on drive shaft 11, causing a change in the electrical signal from piezoelectric element 206 used for grasping detection. By detecting the change in the electrical signal from piezoelectric element 206, control unit 205 detects the start of grasping the object to be grasped by both arm members 3.

[0105] Furthermore, after both arm members 3 start to grasp the object to be grasped, the arm flexure portion 33c of the arm member 3 elastically deforms, causing the state of the friction member 12 sliding freely on the drive shaft 11 to change from when the grasping started, resulting in a change in the electrical signal from the piezoelectric element 206. The control unit 205 can also estimate the gripping force of both arm members 3 by continuing to monitor the electrical signal from the piezoelectric element 206 even after detecting the start of grasping the object to be grasped.

[0106] By using the image information from the imaging device 203 and the position information from the position detection device 204, as well as the electrical signal from the piezoelectric element 206, the control unit 205 can more accurately determine the start of grasping and the grasping force of the object to be grasped by both arm members 3. Note that the grasping device 200 may be configured not to include the imaging device 203 and the position detection device 204, but to detect the start of grasping and estimate the grasping force based on changes in the electrical signal of the piezoelectric element 206 to which the weight member 207 is attached.

[0107] Next, we will explain an example of a method for controlling the driving force of the driving device 1. In the driving device 1, the magnitude of the driving force for the relative movement between the drive shaft 11 and the friction member 12 can be controlled by changing the driving waveform, such as the amplitude and pulse width of the sawtooth driving pulse waveform applied to the piezoelectric element 14. For example, a weak driving force can be obtained by reducing the amplitude of the driving pulse waveform.

[0108] However, if the amplitude of the drive pulse waveform is made too small, it is not possible to apply a force greater than the static friction force between the drive shaft 11 and the friction member 12, which limits the amount of weak drive force that can be obtained. The inventors of the present application have discovered a method for obtaining a weaker drive force while using a drive pulse waveform that can apply a force greater than the static friction force between the drive shaft 11 and the friction member 12.

[0109] 15 shows an example of a timing chart of a drive pulse waveform that can obtain a weak drive force. To move the drive shaft 11 and the friction member 12 relative to each other, n waveforms P1 (n cycles) in a drive direction that can move the drive shaft 11 and the friction member 12 relative to each other are input to the piezoelectric element 14. Here, n is an integer of 2 or greater. Next, p pause periods (p is 0 or a positive integer) with the same cycle as the waveform P1 are input. Next, na waveforms P2 in the opposite drive direction are input (a is a positive integer less than n).

[0110] Next, q pause times (q is 0 or a positive integer) with the same cycle as the waveform P1 are input. Next, n waveforms P1 in the drive direction are input. After that, input of p pause times, input of na waveforms P2, and input of q pause times are repeated.

[0111] In this way, by inputting n drive direction waveforms P1 to the piezoelectric element 14 and then inputting an opposite direction waveform P2 with or without p pauses, the relative movement amount between the drive shaft 11 and the friction member 12 can be reduced, resulting in a weak drive force. For example, a weak drive force can be obtained using a waveform that generates a strong drive force. Note that the above n, a, p, and q are basically positive integers. However, the first or last cycle of the input of n waveforms P1, p pauses, na waveforms P2, and q pauses does not have to be an integer.

[0112] Although the embodiments have been described above, the present invention is not limited to the above-described embodiments and can be embodied in various forms. The configuration of each part is not limited to the illustrated embodiments, and various modifications are possible within the scope of the spirit of the present invention. For example, the configurations described in the above-described embodiments and modified examples (notes, etc.) may be combined, and additions, omissions, substitutions, and other modifications of the configurations are possible.

[0113] For example, the drive device 1 is not limited to one equipped with the friction engagement unit 10 having the friction member 12 and the elastic member 13, and is not particularly limited to a configuration as long as the drive shaft 11 and the friction member 12 can be moved relative to each other by the drive of the piezoelectric element 14. For example, the friction engagement between the drive shaft 11 and the friction member 12 may be achieved by an elastic spring such as a leaf spring or a compression coil spring. Also, the friction member 12 may be fixed to the case 2 or the machine base 201, and a cam plate 9 may be connected to the tip of the drive shaft 11 so that the arm member 3 can be opened and closed.

[0114] 1 to 10, the circuit board 5 may be disposed in, for example, an empty space in the drive device storage section 22. This allows the overall length of the case 2 to be shortened, and a compact gripping device 100 to be formed. [Explanation of symbols]

[0115] 1. Drive unit 2 cases 2a Front end opening 3 Arm parts 4 batteries 5 Circuit Board 6 Operation switch 7A power switch 7B Operation setting member 8. Gripping member 9 Cam plate 10 Friction engagement unit 11 Drive shaft 11a Axial plane 12 Friction member 12a Friction plane 13 Elastic member 14 Piezoelectric element 19 Boss Section 20 Case body 21 Arm storage area 21a Arm Covers 22 Drive unit storage section 22a Drive unit cover 23 Battery compartment 23a Battery cover 24 Circuit board storage compartment 24a Circuit board cover 25 Boss section 26 Drive unit support base 27 Partition 28 Substrate support stand 29 Boss Section 30 Arm support shaft 31 Arm fulcrum 32 Arm middle part 33 Arm opening and closing section 33a Arm tip 33b Detection gap 33c Arm flexure 34 Cam follower 80 Pin member 81 Plate-shaped elastic member 81a Slope section 82 Connecting part 91 Cam groove 92 Cam body 93 Cam arm 100 Gripping device 200 Gripping device 201 machine 201a Camera stand 203 Imaging device 204 Position detection device 205 Control Unit 206 Piezoelectric element for grip detection 207 Weight member A No-load characteristic curve B. Characteristic curve when grasping an object F Camera field of view G deviation amount P Grasp starting point

Claims

1. a driving device that moves a friction member frictionally engaged with the drive shaft and the drive shaft relative to each other in the axial direction of the drive shaft by driving a piezoelectric element that is fixed to one end of the drive shaft and converts an electrical signal into mechanical vibration; a case that houses the drive unit; a pair of arm members supported by the case at the other end of the drive shaft and opening and closing in response to relative movement between the drive shaft and the friction member; a battery housed in the case on the opposite side of the drive shaft with respect to the piezoelectric element; a circuit board housed in the case for controlling the driving of the piezoelectric element; and an operation switch provided on the outer wall of the case for vibrating and stopping the piezoelectric element.

2. a power switch that turns on and off the supply of power from the battery to the circuit board, and / or an operation setting member that changes the operation mode of the drive device; On the outer wall of the case, the operation switch is provided at a position closer to the arm member, while the power switch and the operation setting member are provided at positions farther from the arm member than the battery. The gripping device according to claim 1 .

3. a cam plate connected to the friction member or the drive shaft, and moving along the axial direction of the drive shaft in response to relative movement between the drive shaft and the friction member; The arm member includes an arm fulcrum portion rotatably supported on a support shaft provided on the case, an arm intermediate portion provided on the left and right outer sides of the fulcrum portion, an arm opening / closing portion extending from the intermediate portion to the tip side of the case, and cam followers protruding from the intermediate portion and fitting into left and right cam grooves provided on the cam plate. The gripping device according to claim 1 or 2.

4. a pair of left and right plate-shaped elastic members whose base ends are fixed to the case at positions closer to the arm fulcrum than the tip ends of the left and right arm opening / closing sections, and whose tip ends are spaced apart from each other; The pair of left and right plate-shaped elastic members are provided so that their tip ends can be opened and closed relative to each other by the arm opening / closing parts slidingly contacting the longitudinal midpoints of the plate-shaped elastic members in response to opening and closing operations of the arm members. The gripping device according to claim 3.

5. a slider member connected to the friction member or the drive shaft, slidable along the axial direction of the drive shaft by relative movement between the drive shaft and the friction member, the slider tip portion on the opposite side to the piezoelectric element being bifurcated left and right; a pair of left and right plate-shaped elastic members as the arm members, the base ends of which are fixed to the case between the left and right tip ends of the slider member, and the tip ends of which are spaced apart from each other; The pair of left and right plate-like elastic members are provided so that the tip ends thereof can be opened and closed relative to each other by the tip ends of the sliders coming into sliding contact with the longitudinal midpoints of the plate-like elastic members in response to the sliding movement of the slider members. The gripping device according to claim 1 or 2.

Images