JP2008018489A - Gripping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gripping device capable of simultaneously satisfying two demands to increase the speed of movement of a finger and to increase gripping force by using a small low output actuator. <P>SOLUTION: This gripping device is furnished with at least a finger 2 free to move to bend, a driving wire 7 to transmit bending driving force to the finger to actuate this finger to bend, bending driving mechanisms 3, 130, 320 to influence the bending driving force on this driving wire and step-up mechanisms 5, 140, 330 to influence gripping force larger than the bending driving force on the driving wire. The gripping force is influenced on the driving wire by the step-up mechanisms after the bending driving force is influenced on the driving wire by the bending driving mechanisms. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gripping device that can be used as an electric prosthetic hand or a robot hand.

  In a gripping device such as an electric prosthetic hand or a robot hand, at least one finger is provided, and an object is gripped by bending the finger. In such a case, when the finger is bent toward the object, not only a certain speed is required for the movement of the finger, but also when the object is grasped by the finger, the object is surely grasped. Therefore, a considerable gripping force is also required. Both of these requirements can be met by the use of a large high-power actuator, but it is not possible to incorporate a large high-power actuator into the gripping device.

  Therefore, a small low-power actuator is used for the gripping device as described above. However, in this case, the finger speed and the gripping force are in a trade-off relationship in the reduction ratio. That is, in order to increase the finger speed, the reduction ratio must be reduced, and in order to increase the finger gripping force, the reduction ratio must be increased. Therefore, it is extremely difficult to simultaneously satisfy two contradictory demands of increasing the gripping force while increasing the speed of finger movement.

  Therefore, an object of the present invention is a gripping device such as a prosthetic hand or a robot hand, and simultaneously satisfies the two requirements of increasing the gripping force while increasing the speed of finger movement by using a small low-power actuator. It is to provide a novel gripping device configured to obtain.

  A gripping device according to the present invention includes at least one finger that can be bent, a drive wire that transmits a bending drive force to the finger to cause the finger to bend, a bending drive mechanism that applies the bending drive force to the drive wire, And a force-increasing mechanism that exerts a gripping force larger than the bending driving force on the driving wire. A gripping device in which a bending driving force is exerted on a driving wire by a bending driving mechanism, and then a gripping force is exerted on the driving wire by a force increasing mechanism.

  In the first aspect of the present invention, the force-increasing mechanism includes a pulley assembly, and the pulley assembly includes a shaft that is rotatably held, an eccentric cam fixed on the shaft, and the eccentric cam. The drive wire is operatively connected to the bending drive mechanism via the annular pulley so that the drive wire exerts a bending drive force on the finger, and the eccentric cam is driven to rotate, The annular pulley is displaced so as to exert a gripping force.

  In the second aspect of the present invention, the bending drive mechanism is displaceable with respect to the force-increasing mechanism, and the force-increasing mechanism includes an eccentric cam assembly that engages with the bending drive mechanism. The gripping force is exerted on the drive wire by displacing the mechanism.

  In the third aspect of the present invention, the force-increasing mechanism is displaceable with respect to the bending drive mechanism, the force-increasing mechanism includes a pulley assembly, and the pulley assembly so that the driving wire exerts a bending driving force on the fingers. The pulley is operatively connected to the bending drive mechanism via the pulley, and the force-increasing mechanism displaces the pulley assembly to exert a gripping force on the drive wire.

  In the present invention, preferably, the bending drive mechanism includes a threaded rod, a movable body screwed to the threaded rod, and a guide rail that guides the movable body in a non-rotating state, and the drive wire (7) is Connected to movable body.

  Next, a first embodiment of a gripping device according to the present invention will be described with reference to FIGS.

  First, referring to FIG. 1, a gripping device according to the present invention includes a palm portion 1 formed as a rectangular plate, four fingers 2 provided along one side of the palm portion 1, and these fingers 2. In cooperation with the four bending drive mechanisms 3, the four bending drive mechanisms 3 provided on the palm 1, the electric motor 4 as an actuator for operating these bending drive mechanisms 3, and the four bending drive mechanisms 3. Thus, it is composed of a force-increasing mechanism 5 provided on the palm 1 so as to give a large gripping force to the four fingers 2, and an electric motor 6 as an actuator for operating the force-increasing mechanism 5. The four fingers 2 have substantially the same configuration as each other, and the four drive mechanisms 3 have substantially the same configuration.

  A driving wire 7 is stretched between each finger 2 and the corresponding bending driving mechanism 3, and a bending driving force is transmitted from the bending driving mechanism 3 to the finger 2 via the driving wire 7. Is also used to transmit a gripping force from the force-increasing mechanism 5 to the corresponding finger 2.

  In FIG. 1, reference numerals 8 a, 8 b, 8 c, and 8 d denote attachment plates installed on the palm 1, and the four electric motors 4 are held by the attachment plates 8 a, and the electric motor 6 is attached to the attachment plate 8 a and 8b. Further, a part of each of the two bending drive mechanisms 3 is incorporated between the attachment plate 8a and the attachment plate 8c, and each of the remaining two bending drive mechanisms is provided between the attachment plate 8a and the attachment plate 8d. Part of is incorporated.

  In FIG. 1, reference numeral 9 a indicates a pair of mounting plates installed on the palm 1, and reference numeral 9 b indicates a pair of mounting blocks disposed between the pair of mounting plates 9 a and installed on the palm 1. The force-increasing mechanism 5 is held by the mounting plate 9a and the mounting block piece 9b.

  As will be apparent from the description below, a portion of the force-increasing mechanism 5 is shared by the bending drive mechanism 3 so that the bending drive mechanism 3 and the force-increasing mechanism 5 cooperate with each other. That is, it can be said that a part of one of the bending drive mechanism 3 and the force-increasing mechanism 5 forms a part of the other.

  Referring to FIG. 2 in which only one of the four fingers 2 of FIG. 1 is extracted and shown as a perspective view, the finger 2 has a mounting seat 21 fixed on the palm 1 and the mounting seat 21. A finger piece 22 rotatably mounted around the rotation axis A1, a finger piece 23 rotatably attached to the finger piece 22 around the rotation axis A2, and a finger piece 23 The finger piece 24 is rotatably mounted around the rotation axis A3. A pulley 25 is rotatably provided at a shaft attachment portion of the finger piece 22 with respect to the mounting seat 21, and a pulley 26 is rotatably provided at a shaft attachment portion of the finger piece 23 with respect to the finger piece 22. A pulley 27 is rotatably provided on the shaft mounting portion 24.

  The finger piece 22 includes a pair of links 22a and 22b, and short shafts 22c and 22d are provided between the pair of links 22a and 22b. A protrusion 22e is projected from the outer wall surface of the link 22a at a position close to the rotation axis A2, and the protrusion 22e is a stopper for limiting the rotational movement of the finger piece 23 around the rotation axis A2, as will be described later. Function as.

  The finger piece 23 includes a pair of links 23a and 23b, and a short shaft 23c is provided between the pair of links 23a and 23b. A projection 23d is projected from the inner wall surface of the link 23b at a location close to the rotation axis A3, and this projection 23d is for restricting the rotational movement of the finger piece 24 around the rotation axis A3 as will be described later. Functions as a stopper.

  The finger piece 24 is composed of a pair of links 24a and 24b, and a plate-like piece 24c is stretched on one side between the pair of links 24a and 24b, and between the pair of links 24a and 24b on the plate-like piece 24c. The block piece 24d is fixed.

The shaft attachment portion of the fingers 22 relative to the mount seat 21 _first torsion spring 28 is mounted adjacent to the pulley 25, the arm end portion of one of which is latched into the groove of the mounting seat 21 and the other arm end of the Is hung on the short shaft 22d. Further, the shaft attachment portion of the fingers 23 against the fingers 22 _second torsion spring 28 is mounted adjacent to the pulley 26, the arm end portion of one of which is hooked to the short axis 22c, its other arm end of the Is hung on the short shaft 23c. Further, the shaft attachment portion of the fingers 24 against the fingers 23 the torsion spring 28 ₃ is mounted adjacent to the pulley 27, the arm end portion of one of which is hooked to the short axis 23c, its other arm end of the Is hung on the block piece 24d. Location by the elastic action of these torsion springs 28 _1, 28 ₂ and 28 _3, when an external force of what such as finger 2 is not exerted, the state that the finger pieces 22, 23 and 24 extending in a straight line as shown in FIG. 2 It is burned.

As shown in FIG. 2, the drive wire 7 is wound around the pulleys 25, 26 and 27 once, and then the tip thereof is appropriately fixed to the block piece 24d. Thus, when the driving wire 7 is pulled against the elastic force of the torsion spring ₂₈ 1, 28 ₂ and 28 _3, fingers 22, 23 and 24 is rotated at each rotation about axis A1, A2 and A3 As a result, the finger 2 is bent. During the bending operation of the finger 2, the rotational movement of the finger piece 23 is limited by the protrusion or stopper 22e, and similarly the rotational movement of the finger piece 24 is limited by the protrusion or stopper 23d.

  Referring to FIG. 3, which shows a perspective view of only one part of the four bending drive mechanisms 3 of FIG. 1, the bending drive mechanism 3 includes a threaded rod 31 connected to the output shaft of the electric motor 4. The threaded rod 31 includes a bearing 32 that rotatably supports the tip of the threaded rod 31 and a movable body 33 that is screwed onto the threaded rod 31. As already described with reference to FIG. 1, the electric motor 4 is appropriately held by the mounting plate 8a, while the bearing 32 is appropriately held by the mounting plate 8c or 8d. That is, the threaded rod 31 is extended between the mounting plate 8a and the mounting plate 8c or 8d.

  Referring again to FIG. 1, a pair of side guide rails 34 a and a central guide rail 34 b are laid on the palm 1 between the mounting plate 8 a and the mounting plate 8 c or 8 d. Each bending drive mechanism 3 includes one of a pair of side guide rails 34a and a central guide rail 34b as its constituent elements. In other words, the central guide rail 34b is shared by two adjacent bending drive mechanisms 3 provided between the mounting plate 8a and the mounting plate 8c or 8d. The movable body 33 of each bending drive mechanism 3 is accommodated in a non-rotating state and slidably between the corresponding side guide rail 34a and the corresponding center guide rail 34b. Thus, when the threaded rod 31 is rotated by driving each electric motor 4, the movable body 33 is moved along the threaded rod 31.

  Referring to FIG. 4 which is a perspective view of the force-increasing mechanism 5 extracted from FIG. 1, the power-increasing mechanism 5 includes a shaft 51 stretched between a pair of mounting plates 9a and rotatably supported by an appropriate bearing. A bevel gear 52 fixed on the shaft 51, a bevel gear 53 meshing with the bevel gear 52 and mounted on the output shaft of the electric motor 6, and four pulley assemblies 54 provided on the shaft 51. . That is, the rotational driving force of the electric motor 6 is transmitted from the bevel gear 53 to the bevel gear 52, and thereby the shaft 51 is rotationally driven. Although not shown in FIG. 4, a mounting block 9b (see FIG. 1) is provided between two pulley assemblies 54 adjacent to each mounting plate 9a, and the shaft 51 is supported by these mounting blocks 9b. Is also held rotatably.

  The four pulley assemblies 54 have substantially the same configuration, and each of the pulley assemblies 54 is shared with one of the four bending drive mechanisms 3 described above. That is, each bending drive mechanism 3 includes the corresponding pulley assembly 54 as a part of its constituent elements.

Referring to FIG. 5, which is an exploded perspective view of one of the pulley assemblies shown in FIG. 4, the pulley assembly 54 comprises a disk member 54a, and a shaft 51 (see FIG. 4) is attached to the disk member 54a. An eccentric hole 54 a ₁ for insertion is formed, and the disk member 54 a is fixed on the shaft 51 as appropriate. The pulley assembly 54 further includes an annular bearing 54b that receives the disk member 54a and an annular pulley 54c that receives the annular bearing 54b, and the annular pulley 54c is rotatable with respect to the disk member 54a. Is done.

In short, as shown in FIG. 4, the disc member 54a is by inserting the shaft 51 is suitably fixed in position on the eccentric aperture 54a _1, this time circular plate member 54a functions as an eccentric cam, the annular pulley 54c is It functions as a cam follower, and the four eccentric cams 54a are arranged on the shaft 51 so as to have the same phase.

  An appropriate bearing element such as a ball bearing element or a roller bearing element may be incorporated in the outer peripheral surface of the disk member 54a or the inner peripheral surface of the annular pulley 54c. In this case, the annular bearing 54b can be omitted.

  Referring to FIG. 1 again, each of the drive wires 7 of the four fingers 2 is wound around the annular pulley 54c of the pulley assembly 54 by a half circumference, and its tip is passed through the mounting plate 8c or 8d to correspond to the corresponding movable body. 33.

  Next, the operation of the first embodiment of the gripping device described above will be described with reference to FIGS. 6 and 7 are operation explanatory views for explaining the operation of the pulley assembly 54, and for the convenience of explanation, the eccentric cam 54a and the annular pulley 54c are indicators for indicating the respective rotational angle positions. An orthogonal coordinate system X-Y having Ia and Ic and having an origin at the center of the shaft 51 is set.

  First, referring to FIG. 6A, the movable body 33 and the pulley assembly 54 when the gripping device is placed in the initial state are illustrated. In the initial state of the gripping device, the movable body 33 is placed at the initial position closest to the mounting plate 8c or 8d, and at this time, the four fingers 2 are placed in a straight line (see FIG. 1). . On the other hand, in the pulley assembly 54, the eccentric cam 54a and the annular pulley 54c take an initial rotational position such that their indexes Ia and Ic are aligned with each other along the X axis.

Next, as shown in FIG. 6B, when the movable body 33 is moved from the initial position along the guide rails 34a and 34b to the mounting plate 8a side by driving the electric motor 4, the drive wire 7 is moved. pulled the torsion spring 28 _1, 28 ₂ and 28 ₃ pulley assembly 54 side against the elastic force of which the initial rotational position annular pulley 54c is around the annular body 54b with finger 2 is bent operation ( 6 (A)), it is rotated clockwise by an angle of approximately 45 degrees.

  Next, as shown in FIG. 6C, by driving the electric motor 4, the movable body 33 is further moved toward the mounting plate 8a, and the finger 2 is further bent, and the annular pulley 54c is further advanced. Is rotated around the annular body 54b from the initial rotation position ((A) of FIG. 6) to an angle of 90 degrees clockwise. If the finger 2 is in contact with the object to be gripped at this time, the driving of the electric motor 4 corresponding to the finger 2 is forcibly stopped. At this time, an excessive current flows through the electric motor 4, and this excess current is reduced. By detecting, the electric motor 4 is turned off. When all the electric motors 4 are turned off, the electric motor 6 of the force-increasing mechanism 5 is driven to rotate the shaft 51 in the clockwise direction.

  Next, as shown in FIG. 7A, due to the clockwise rotation of the shaft 51, the eccentric cam 54a is moved slightly less than 45 degrees clockwise from the initial position (FIG. 6C) within the annular body 54b. When the eccentric cam 54a is rotated, the annular body 54b and the annular pulley 54c are displaced away from the mounting plate 8c or 8d along with the rotation of the eccentric cam 54a. A large tension, that is, a gripping force is applied to the object through the drive wire 7.

  As shown in FIG. 7B, the shaft 51 is further rotated clockwise by the drive of the electric motor 6, and the eccentric cam 54a is moved from the initial position (FIG. 6C) in the annular body 54b. When rotated 90 degrees in the direction, the annular body 54b and the annular pulley 54c are displaced to the farthest position from the mounting plate 8c or 8d. At this time, the object gripped by the finger 2 reaches the maximum via the drive wire 7. A gripping force is exerted.

  Next, with reference to FIG. 8, the balance of force when the eccentric cam 54a is rotationally driven will be described. 8A corresponds to FIG. 6C, and FIG. 8B corresponds to FIG. 7A.

When the eccentric cam 54a is rotated by the torque τ by the rotation angle Δθ from the initial position shown in FIG. 8A to the position shown in FIG. 8B, the annular pulley 54c is displaced by Δx. . Considering the virtual work at this time, the following formula is established.
τ ・ Δθ = 2T ・ Δx
Here, T is the tension exerted on the drive wire 7.

The above formula is summarized for the tension T as follows.
T = (Δθ / Δx) ・ (τ / 2)
Here, when θ → π / 2, Δθ → 0, and therefore T → ∞.

  Thus, it can be seen that a very large tension or gripping force can be exerted on the drive wire 7. Of course, the magnitude of the tension T actually obtained is limited due to elastic deformation of the components constituting the finger 2, the drive wire 7, and the like.

  According to the structure of the gripping device as described above, since a large load is not applied to the bending operation of the finger 2, the electric motor 4 can be a low output type small one and the bending operation of the finger 2 can be performed. It can be done at high speed. On the other hand, after the finger 2 is brought into contact with the object to be grasped by the bending operation of the finger 2, the force-increasing mechanism 5 is operated, thereby obtaining a large gripping force. Further, since a large gripping force can be obtained by the force-increasing mechanism 5, the electric motor 6 can also be a low-output type small one.

  Next, a second embodiment of the gripping device according to the present invention will be described with reference to FIGS. 9 is a partial plan view showing a second embodiment of the gripping device according to the present invention, FIG. 10 is a partial sectional view taken along line XX of FIG. 9, and FIG. FIG. 12 is a sectional view taken along line XI, and FIG. 12 is a sectional view taken along line XII-XII in FIG.

  First, referring to FIG. 9, only a part of the palm 1 is illustrated. As in the case of the first embodiment described above, the palm 1 is shown in FIG. 1 along one side thereof. Four fingers 2 as shown are provided.

  Referring to FIG. 10, FIG. 11 and FIG. 12, in the second embodiment, guide rails 11 and 12 are laid on the palm 1 and these guide rails 11 and 12 extend in the length direction of the finger (2). Extended along. Movable frame bodies 110 and 120 are slidably installed on the guide rails 11 and 12, respectively, and the movable frame bodies 110 and 120 can move along the guide rails 11 and 12, respectively.

  More specifically, the movable frame 110 includes a rectangular bottom plate 111 and upright wall portions 112 and 113 integrally standing upright from both ends of the rectangular bottom plate 111, that is, from both ends along the length direction of the guide rail 11. The movable frame 112 also has a rectangular bottom plate 121, and upright wall portions 122 that are integrally upright from both ends of the rectangular bottom plate 121, that is, both ends along the length direction of the guide rail 12. 123. As shown in FIG. 11, a pair of sliding shoes 114 slidably engaged with the guide rail 11 is provided on the bottom surface of the rectangular bottom plate 111, and as shown in FIG. A pair of sliding shoes 124 that are slidably engaged with the guide rail 12 are provided on the back surface of the plate 121, thereby sliding the movable frame bodies 110 and 120 along the guide rails 11 and 12, respectively. Dynamic movement is possible.

  Referring to FIG. 9 again, in the second embodiment, each of the movable frame bodies 110 and 120 is equipped with two bending drive mechanisms 130 for driving the two fingers (2) to be bent, respectively. Each of these four bending drive mechanisms 130 is driven by the electric motor 4 supported by the upright wall 113 or 123, whereby the bending operation of the four fingers (2) is performed as described later. Become. The four bending drive mechanisms 130 have substantially the same configuration.

  More specifically, each bending drive mechanism 130 is connected to the output shaft of the electric motor 4 and has a threaded rod 131 rotatably supported between the upright wall portions 112 and 113 or the upright wall portions 122 and 123. The movable member 132 is screwed to the rod 131. Each bending drive mechanism 130 includes a pair of guide rails 133a and 133b laid along one side of the rectangular bottom plate 111 or 121, and each movable body 132 includes the pair of guide rails 133a and 133b. And is slidably accommodated in a non-rotating state. Similarly to the first embodiment described above, the drive wire 7 is connected to each movable body 132, and thus when the threaded rod 131 is rotated by driving each electric motor 4, the movable body 132 is moved to the threaded rod 131. Accordingly, the bending motion of the corresponding finger (2) is performed.

  In order to give a large gripping force to the four fingers 2 in cooperation with the four bending drive mechanisms 130, a force-increasing mechanism 140 is provided on the palm 1, and this force-increasing mechanism 140 is movable on the palm 1. 110 and 120 are held by four mounting plates 150a, 150b, 150c and 150d installed in a straight line along the upright wall 112 or 122 side.

  More specifically, as shown in FIGS. 9 and 10, the force-increasing mechanism 140 includes a shaft 141 rotatably supported by mounting plates 150a, 150b, 150c, and 150d, and two shafts provided on the shaft 141. And an eccentric cam assembly 142. One of the two eccentric cam assemblies 142 is disposed between the mounting plates 150a and 150b and engaged with the upright wall 112 of the movable frame 110, and the other is disposed between the mounting plates 150c and 150d. Thus, the upright wall 122 of the movable frame 120 is engaged. The force-increasing mechanism 140 is driven on the palm 1 by an electric motor 6 provided between the movable frame bodies 110 and 120, and this electric motor 6 is cantilevered on a mounting plate 160 installed on the palm 1. It is held in a manner. In order to drive the force-increasing mechanism 140 by the electric motor 6, the force-increasing mechanism 140 includes a bevel gear 143 attached to the output shaft of the electric motor 6, a bevel gear 144 that meshes with the bevel gear 144 and is attached to the shaft 141. It comprises. That is, when the electric motor 6 is driven, the shaft 141 is rotationally driven by the bevel gears 143 and 144.

  As shown in FIGS. 11 and 12, each eccentric cam assembly 142 includes a roll member 142a. The roll member 142a has an eccentric hole through which the shaft 141 is inserted, and the roll member 142a is formed on the shaft 141. It is fixed appropriately. Each eccentric cam assembly 142 further includes a cylindrical bearing 142b that receives the roll member 142a and a cylindrical member 142c that receives the cylindrical bearing 142b, and the cylindrical member 142c becomes the roll member 142a by the cylindrical bearing 142b. On the other hand, it can rotate freely.

  In short, in the eccentric cam assembly 142 as described above, the roll member 142a functions as an eccentric cam, the cylindrical member 142c functions as a cam follower, and the two eccentric cams 142a have the same phase on the shaft 141. Placed in.

  An appropriate bearing element such as a ball bearing element or a roller bearing element may be incorporated in the outer peripheral surface of the roll member 142a or the inner peripheral surface of the cylindrical member 142c. In this case, the cylindrical bearing 142b can be omitted.

  Next, the operation of the second embodiment of the gripping device described above will be described with reference to FIG. 13A, 13B, and 13C are cross-sectional views corresponding to FIG. 12, respectively.

First, referring to FIG. 13A, the movable body 132 and the eccentric cam assembly 142 when the gripping device is placed in the initial state are illustrated in the second embodiment. In the initial state of the gripping device, the movable body 132 is placed at the initial position closest to the upright wall 122, and at this time, the four fingers (2) are placed in a straight line (see FIG. 1). ). Incidentally, the four fingers (2) when they are placed in a state of being extended in a straight line, a torsion spring (28 in each incorporated in its finger (2) of the drive wire _71, 28 ₂ and 28 ₃ ), an appropriate tension is applied, so that the upright walls 112 and 122 of the movable frame bodies 110 and 120 are in elastic contact with the cylindrical member 142c of the eccentric cam assembly 142, respectively. Placed in.

  On the other hand, in the initial state of FIG. 13A, in the eccentric cam assembly 142, the eccentric cam 142a has an initial position where the shaft 141 is closest to the upright walls 112 and 122 of the movable frame bodies 110 and 120. I take the.

Next, as shown in FIG. 13 (B), when the electric motor 4 is driven, the movable body 132 is moved from the initial position along the guide rails 133a and 133b to the upright wall 113 or 123 side. The wire 7 is pulled against the elastic force of the torsion springs (28 ₁ , 28 ₂ and 28 ₃ ), and thereby the finger (2) is bent. If the finger (2) contacts the object to be grasped while the finger (2) is bending, the driving of the electric motor 4 corresponding to the finger (2) is forcibly stopped. At this time, the electric motor 4 An excessive current flows through the electric motor 4, and the electric power of the electric motor 4 is turned off by detecting the excessive current. When all the electric motors 4 are powered off, the electric motor 6 of the force-increasing mechanism 142 is driven to rotate in either direction.

  As shown in FIG. 13C, when the shaft 141 is rotated by the rotational drive of the electric motor 6, and thereby the eccentric cam 142a is rotated from the initial position to 180 degrees, the movable frame bodies 110 and 120 are Both of them are displaced away from the eccentric cam assembly 142, and at this time, a large tension, that is, a gripping force is exerted on the object gripped by the finger (2) through the driving wire 7 due to the increasing action of the eccentric cam 142 a.

  Similarly to the case of the first embodiment described above, in the second embodiment shown in FIGS. 9 to 12, the electric motor 4 has a low output because the bending operation itself of the finger (2) is not subjected to a large load. A small type can be used and the finger (2) can be bent at high speed. On the other hand, after the finger (2) comes into contact with the object to be grasped by the bending operation of the finger (2), the force-increasing mechanism 142 is operated, thereby obtaining a large gripping force. In addition, since a large gripping force can be obtained by the force-increasing mechanism 142, the electric motor 6 can be a low-output type small one.

  Next, a third embodiment of the gripping device according to the present invention will be described with reference to FIGS. 14 is a partial plan view showing a third embodiment of the gripping device according to the present invention, FIG. 15 is an elevational view taken along line XV-XV in FIG. 14, and FIG. 16 is XVI- in FIG. FIG. 17 is a sectional view taken along line XVII-XVII in FIG. 14.

  First, referring to FIG. 14, only a part of the palm 1 is illustrated. As in the case of the first embodiment described above, the palm 1 is shown in FIG. 1 along its one side. Four fingers 2 as shown are provided. Mounting plates 310a, 310b, 310c and 310d are installed on the palm 1, and the mounting plates 310a and 310b are arranged so as to be aligned with each other along the length direction of the finger (2). 310d is also arranged to align with each other along the length of the finger (2).

  In the third embodiment, the mounting plates 310a and 310b are provided with two bending drive mechanisms 320 for driving the two fingers (2) to be bent, respectively, and the mounting plates 310c and 310d are also provided with two fingers. Two bending drive mechanisms 320 for driving the bending of (2) are provided. The bending drive mechanism 320 provided on the mounting plates 310a and 310b is driven by the electric motor 4 supported on the mounting plate 310a, and thereby the corresponding finger (2) is driven to be bent. Similarly, the bending drive mechanism 320 provided on the mounting plates 310c and 310d is driven by the electric motor 4 supported on the mounting plate 310c, and thereby the bending drive of the corresponding finger (2) is performed as described later. . Note that these bending drive mechanisms 320 have substantially the same configuration.

  More specifically, each bending drive mechanism 320 is connected to the output shaft of the electric motor 4 and is rotatably supported between the mounting plate 310a or 310c and the mounting plate 310b or 310d, and the threading rod 321. And a movable body 322 that is screwed onto the body.

  In addition, a pair of side guide rails 323 a and a central guide rail 323 b are laid on the palm 1 between the attachment plate 310 a or 310 c and the attachment plate 310 b or 310 d. Each bending drive mechanism 320 includes one of a pair of side guide rails 323a and a central guide rail 323b as its constituent elements. In other words, the central guide rail 323b is shared by two adjacent bending drive mechanisms 310 provided between the mounting plate 310a or 310c and the mounting plate 310b or 310d. The movable body 322 of each bending drive mechanism 310 is slidably accommodated between the corresponding side guide rail 323a and the corresponding center guide rail 323b in a non-rotating state. Thus, when the threaded rod 321 is rotated by driving each electric motor 4, the movable body 322 is moved along the threaded rod 321.

  Further, in the third embodiment, a force-increasing mechanism 330 is provided along the attachment plates 310b and 310d, and this force-increasing mechanism 330 includes a pulley assembly that is movable in the front-rear direction with respect to the attachment plates 310b and 310d. The pulley assembly includes a movable beam-like member 331 and four pulleys 332 rotatably incorporated in the movable beam-like member 331.

  More specifically, as shown in FIGS. 14 and 15, the movable beam-like member 331 is formed with grooves corresponding to the moving paths of the four movable bodies 332, and pulleys 332 are provided in each of these grooves. It is housed rotatably. That is, a hole is formed so as to pass through two groove portions adjacent to the end surface from each end surface side of the movable beam-shaped member 331, and the pulley 332 is rotatably mounted on the shaft inserted through the hole.

  As shown in FIGS. 14 to 17, a pair of guide rails 13 and 14 are laid on the palm 1 in order to make the movable beam-like member 331 movable in the front-rear direction with respect to the mounting plates 310b and 310d. These guide rails 13 and 14 are extended along the length direction of the finger (2). On the other hand, sliding shoes 333 and 334 that are slidably engaged with the guide rails 13 and 14, respectively, are attached to the bottom surface of the movable beam-shaped member 331 (see FIGS. 15, 16, and 17). The movable beam-like member 331 can be moved in the front-rear direction with respect to the mounting plates 310b and 310d.

  As shown in FIGS. 14 and 16, the force-increasing mechanism 330 is driven by the electric motor 6, and the electric motor 6 is cantilevered on the mounting plate 340 installed between the mounting plates 310 b and 310 d on the palm 1. It is held in a manner. The force-increasing mechanism 330 includes a screw member 335 mounted on the output shaft of the electric motor 6, and this screw member 335 is screwed into a screw hole formed in the central portion of the movable beam-like member 331 (see FIG. 16). That is, when the screw member 335 is rotated by the electric motor 6, the rotational motion of the screw member 335 is converted into the translational motion of the movable beam-shaped member 331 along the guide rails 13 and 14. Thus, the movable beam-like member 331 can move in the front-rear direction with respect to the mounting plates 310b and 310d.

  As in the case of the first embodiment described above, also in the third embodiment, the pulley 332 is shared by the bending drive mechanism 320 and the force-increasing mechanism 330 and cooperates with each other. That is, it can be said that the four pulleys 332 form part of each of the four bending drive mechanisms 320 and part of the force-increasing mechanism 330.

  As shown in FIGS. 14 and 17, the drive wire 7 extending from the finger (2) is wound around the corresponding pulley 332 by a half turn, and then is passed through the mounting plate 310 b or 310 d to be connected to the corresponding movable body 322. .

  Next, the operation of the third embodiment of the gripping device described above will be described with reference to FIG. 18A, 18B, and 18C are cross-sectional views corresponding to FIG.

  First, referring to FIG. 18A, in the third embodiment, the movable body 322 and the movable beam-like member 331 when the gripping device is placed in the initial state are illustrated. That is, in the initial state of the gripping device, the movable body 322 is placed at the initial position closest to the mounting plate 310b or 310d, and at this time, the four fingers (2) are placed in a straight line (see FIG. (See FIG. 1). On the other hand, the movable beam member 331 is placed at a position closest to the mounting plates 310b and 310d.

Next, as shown in FIG. 18B, when the movable body 132 is moved from the initial position along the guide rails 323a and 323b toward the mounting plate 310a or 310c by driving the electric motor 4, the drive wire 7 Are pulled against the elastic force of the torsion springs (28 ₁ , 28 ₂ and 28 ₃ ), and the finger (2) is bent. If the finger (2) contacts the object to be grasped while the finger (2) is bending, the driving of the electric motor 4 corresponding to the finger (2) is forcibly stopped. At this time, the electric motor 4 An excessive current flows through the electric motor 4, and the electric power of the electric motor 4 is turned off by detecting the excessive current. When the power of all the electric motors 4 is turned off, the electric motor 6 of the force-increasing mechanism 330 is rotated.

  As shown in FIG. 18C, the movable beam-shaped member 331 is moved away from the mounting plates 310a and 310d by the rotational drive of the electric motor 6, and at this time, the finger (2) is increased by the increasing force of the screw member 335. A large tension, i.e., a gripping force, is exerted on the object gripped by (1) through the drive wire 7.

  As in the case of the first and second embodiments described above, in the third embodiment shown in FIGS. 14 to 17 as well, the bending operation of the finger (2) itself is not subjected to a large load. Can use a low-output type small one and can perform the bending operation of the finger (2) at high speed. On the other hand, after the finger (2) comes into contact with the object to be grasped by the bending operation of the finger (2), the force-increasing mechanism 330 is operated, thereby obtaining a large gripping force. Moreover, since a large gripping force can be obtained by the force-increasing mechanism 330, the electric motor 6 can be a low-output type small one.

1 is a perspective view showing a first embodiment of a gripping device according to the present invention. It is a perspective view which extracts and shows one of the fingers of FIG. It is a perspective view which extracts and shows one part of the bending drive mechanism of FIG. It is a perspective view which extracts and shows the power increasing mechanism of FIG. FIG. 5 is an exploded perspective view of the pulley assembly of FIG. 4. It is operation | movement explanatory drawing of the holding | gripping apparatus of FIG. It is operation | movement explanatory drawing of the holding | gripping apparatus of FIG. It is explanatory drawing explaining the effect of the holding | grip apparatus of FIG. It is a partial top view which shows 2nd Embodiment of the holding | gripping apparatus by this invention. It is sectional drawing which follows the XX line of FIG. It is sectional drawing which follows the XI-XI line of FIG. It is sectional drawing which follows the XII-XII line | wire of FIG. It is operation | movement explanatory drawing of the holding | gripping apparatus of FIG. It is a partial top view which shows 3rd Embodiment of the holding | gripping apparatus by this invention. FIG. 15 is an elevational view along line XV-XV in FIG. 14. It is sectional drawing which follows the XVI-XVI line of FIG. It is sectional drawing which follows the XVII-XVII line of FIG. It is operation | movement explanatory drawing of the holding | gripping apparatus of FIG.

Explanation of symbols

1: Palm part 2: Finger 21: Mounting seats 22, 23, 24: Finger pieces 22a, 22b: Links 22c, 22d: Short shaft 22e: Protrusions 22e25, 36, 27: Pulleys 23a, 23b: Link 23c: Short shaft 23d : projections 24a, 24b: link 24c: plate-like pieces 24d: block pieces ₂₈ 1, ₂₈ 2, 28 _3: torsion spring 3: the bending drive mechanism 31: threaded rod 32: bearing 33: movable body 34a: lateral guide rails 34b : Central guide rail 4: Electric motor 5: Booster mechanism 51: Shaft 51
52.53: Bevel gear 54: Pulley assembly 54a: Disk member (eccentric cam)
54a ₁ : eccentric hole 54b: annular body 54c: annular pulley 6: electric motor 7: drive wires 8a, 8b, 8c, 8d: mounting plate 9a: mounting plate 9b: mounting block piece

Claims (5)

At least one finger (2) that can be bent, a drive wire (7) that transmits a bending driving force to the finger to bend the finger, and a bending drive mechanism (3) that applies the bending driving force to the driving wire. , 130, 320) and a force-increasing mechanism (5, 140, 330) that exerts a gripping force larger than the bending driving force on the driving wire, and the bending driving force exerts a bending driving force on the driving wire by the bending driving mechanism. A gripping device in which a gripping force is exerted on the drive wire by the force-increasing mechanism after being applied. The gripping device according to claim 1, wherein the force-increasing mechanism (5) comprises a pulley assembly (54), the pulley assembly being rotatably supported on a shaft (51). The bending drive mechanism comprises a fixed eccentric cam (54a) and an annular pulley (54c) operated by the eccentric cam, and the drive wire exerts a bending drive force on the fingers via the annular pulley. A gripping device in which the annular pulley is displaced so as to exert the gripping force on the drive wire by rotationally driving the eccentric cam. The eccentric cam assembly according to claim 1, wherein the bending drive mechanism (130) is displaceable with respect to the force-increasing mechanism (140), and the force-increasing mechanism engages with the bending drive mechanism. (142), the eccentric cam assembly displaces the force-increasing mechanism, and the gripping force is exerted on the drive wire. The gripping device according to claim 1, wherein the force-increasing mechanism (330) is displaceable with respect to the bending drive mechanism (320), and the force-increasing mechanism includes a pulley assembly (331, 332), A drive wire is operatively connected to the bending drive mechanism via a pulley (332) of the pulley assembly so as to exert a bending drive force on the finger (2), and the force-increasing mechanism displaces the pulley assembly. A gripping device in which the gripping force is exerted on the drive wire. The gripping device according to any one of claims 1 to 4, wherein the bending drive mechanism (3, 130, 320) is screwed onto the threaded rod (31, 131, 321) and the threaded rod. Movable bodies (33, 132, 322) and guide rails (34a, 34b: 133a, 133b: 323a, 323b) for guiding the movable bodies in a non-rotating state, and the drive wire (7) is A gripping device connected to a movable body.

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