Gripping device and work robot equipped therewith

Abstract

The present invention provides a gripping device and a work robot equipped therewith that can shorten the cycle time and improve productivity by gripping an object at high speed. [Solution] A gripping device 1A for gripping an object 11, comprising: a device body 2; a gripping finger 3 pivotally supported so as to be rotatable between an initial position and a gripping position; an initial position return means 4 that constantly applies a force to the gripping finger 3 to return it to the initial position; a reaction force conversion means 5 that receives the reaction force when pressed against the object 11 and converts it into a force that rotates the gripping finger 3 in the direction of the gripping position; and a gripping state holding means 6 that maintains the state in which the gripping finger 3 grips the object 1.

Description

Technical Field

[0001] The present invention relates to a gripping device capable of gripping an object at high speed and a work robot equipped with the same.

Background Art

[0002] Conventionally, various gripping devices represented by robot hands and grippers have been used. For example, Japanese Unexamined Patent Application Publication No. 2024-77915 discloses a gripping device including a main body portion, a plurality of gripping portions extending from the main body portion in a predetermined direction and movable in the horizontal direction, and a regulating portion provided at each tip end portion of the plurality of gripping portions for regulating the movement of an object gripped by the plurality of gripping portions in the direction of gravity (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an object is gripped by a conventional gripping device including the gripping device described in Patent Document 1, generally, as shown in FIG. 17, a step 1 of moving to a position directly above the object to be gripped, a step 2 of moving (descending) to a position where the object can be gripped, a step 3 of moving the gripping fingers to grip the object, and a step 4 of moving the gripped object are sequentially executed.

[0005] The gripping operation consisting of the above steps poses no problem in a scenario where the processing speed of the object is not required. However, in a scenario where a large number of objects need to be processed, such as in-line work in a factory, the time required to process each object (tact time) significantly affects productivity. Therefore, a gripping device that can shorten the tact time as much as possible is desired.

[0006] The present invention was made to solve these problems and aims to provide a gripping device and a work robot equipped therewith that can shorten the cycle time and improve productivity by gripping an object at high speed. [Means for solving the problem]

[0007] The gripping device according to the present invention solves the problem of shortening the cycle time and improving productivity by gripping an object at high speed, and comprises a device body attached to a work robot that moves the gripping device, a gripping finger provided on the device body and pivotally supported so as to be rotatable between an initial position open in the direction away from the object and a gripping position closed toward the object, an initial position return means that constantly applies a force to the gripping finger to return it toward the initial position, a reaction force conversion means that receives the reaction force when pressed against the object and converts it into a force that rotates the gripping finger toward the gripping position, and a gripping state holding means that maintains the state in which the gripping finger, rotated toward the gripping position, grips the object.

[0008] Furthermore, in one aspect of the present invention, in order to solve the problem of easily adjusting the distance between gripping fingers and gripping objects of various sizes, the main body of the device includes left and right guide members that support the gripping fingers so as to be slidable in the left and right directions, a vertically moving member that moves up and down to slide the gripping fingers in the left and right directions, and a link member to which one end is rotatably attached to the gripping fingers and the other end is rotatably attached to the vertically moving member, and when the vertically moving member is moved up and down, the gripping fingers may move in the left and right directions along the left and right guide members via the link member.

[0009] Furthermore, in one aspect of the present invention, in order to solve the problem of making it easier to grasp an object even if it is placed on a flat surface, the gripping finger may be composed of at least a distal phalanx at the tip, an intermediate phalanx in the middle, and a base phalanx provided on the main body of the device, and may have a first joint axis that rotatably connects the distal phalanx and the intermediate phalanx, a second joint axis that rotatably connects the intermediate phalanx and the base phalanx, a first gear provided around the first joint axis and rotating together with the distal phalanx, a second gear provided around the second joint axis and fixed to the base phalanx, an intermediate gear rotatably supported on the intermediate phalanx in a state of meshing with the second gear and rotating in conjunction with the rotation of the intermediate phalanx relative to the base phalanx, a transmission gear fixed coaxially with the intermediate gear, and a transmission belt that transmits the rotational movement of the transmission gear to the first gear and rotates the distal phalanx.

[0010] Furthermore, in one aspect of the present invention, in order to solve the problem of further improving the gripping speed by making contact with the object at an earlier timing and initiating the gripping operation, the gripping finger is provided in a direction that brings it closer to other gripping fingers or fixed fingers when rotated to the gripping position, and the reaction force conversion means may consist of a gripping belt fixed so as to be stretched between the tip of the gripping finger and the tip of other gripping fingers or fixed fingers.

[0011] Furthermore, in one aspect of the present invention, in order to solve the problem of reliably gripping an object by rotating each gripping finger by the same angle even when the object contacts an object at an off-center position from the center of the gripping belt, the gripping fingers are provided in multiple numbers, and each gripping finger has a gripping finger side gear provided on its pivot axis that rotates in conjunction with the rotation of the gripping finger, a body side gear provided for each gripping finger side gear and rotatably supported on the main body of the device, a synchronization gear fixed coaxially with each body side gear, and a transmission member that transmits the rotational movement of each gripping finger side gear to each body side gear, and the rotational movement of one gripping finger may be transmitted to the other gripping fingers by meshing all of the synchronization gears with each other.

[0012] Furthermore, in one aspect of the present invention, in order to solve the problem of adjusting the distance between fingers while maintaining synchronization between each gripping finger, the main body of the device includes left and right guide members that support the gripping fingers so as to be slidable in the left and right directions, an up and down moving member that moves up and down to slide the gripping fingers in the left and right directions, and a link member to which one end is rotatably attached to the gripping finger and the other end is rotatably attached to the up and down moving member, wherein the up and down moving member is rotatably provided with the synchronization gears fixed coaxially with each main body side gear in a meshed state, one end of the link member is rotatably provided on the pivot axis of the gripping finger side gear, and the other end of the link member is rotatably provided on the pivot axes of the main body side gear and the synchronization gear, and when the up and down moving member is moved up and down, the gripping fingers can move in the left and right directions along the left and right guide members via the link member while maintaining synchronization between each gripping finger.

[0013] Furthermore, in one aspect of the present invention, in order to increase the moment when rotating the gripping finger and solve the problem of rotating the gripping finger quickly and reliably, the end of the gripping belt may be fixed at a position away from the gripping belt in a direction that increases the moment applied to the gripping finger.

[0014] Furthermore, in one aspect of the present invention, in order to reduce the risk of contact with surrounding objects or people, and to solve the problem of making it easier to grip by allowing sufficient rotation of the gripping finger by adjusting the gear ratio between the gripping finger side gear and the main body side gear, the fixed arm may be fixed so as to rotate in conjunction with the rotation of the synchronous gear with respect to the same pivot axis as the synchronous gear.

[0015] Furthermore, as one aspect of the present invention, in order to solve the problem of eliminating the power supply of the gripping device and reducing the power consumption to zero, the gripping position holding means is provided on the rotation axis of the gripping finger, and includes a serrated ratchet gear that rotates as the gripping finger rotates, and a locking claw that is engaged with the ratchet gear, rotates the gripping finger only in the direction of the gripping position, and prevents rotation in the direction of the initial position.

[0016] The work robot according to the present invention is provided with the gripping device according to any of the above-described aspects in order to solve the problem of shortening the tact time and improving the productivity by gripping an object at high speed.

Effects of the Invention

[0017] According to the present invention, it is possible to shorten the tact time and improve the productivity by gripping an object at high speed.

Brief Description of the Drawings

[0018] [Figure 1] It is a front view showing a first embodiment of the gripping device according to the present invention and a work robot provided with the same. [Figure 2] It is a front view of the gripping device of the first embodiment. [Figure 3] It is a left side view of the gripping device of the first embodiment. [Figure 4] It is a diagram showing a conversion operation by the reaction force conversion means of the first embodiment. [Figure 5] It is another example of the reaction force conversion means, and is a diagram showing (a) the state where the gripping finger is in the initial position and (b) the state where the gripping finger is in the gripping position. [Figure 6] It is a diagram showing the operation of the gripping state holding means in the first embodiment. [Figure 7] It is a diagram showing a gripping operation by the gripping device of the first embodiment. [Figure 8] It is a perspective view of the gripping device of the second embodiment. [Figure 9] It is a left side view of the gripping device of the second embodiment. [Figure 10] It is a rear view of the gripping device of the second embodiment. [Figure 11] In the gripping device of the second embodiment, it is a diagram showing (a) a state where the distance between fingers is narrowed, (b) a state where the distance between fingers is medium, and (c) a state where the distance between fingers is widened. [Figure 12] In the gripping device of the second embodiment, it is a diagram showing (a) a state where the middle finger part starts to rotate with respect to the second joint axis and (b) a state where the distal finger part rotates with respect to the first joint axis. [Figure 13] It is a photograph showing the experimental situation of Example 1. [Figure 14] It is a photograph showing the experimental situation of Example 2. [Figure 15] It is a photograph showing the experimental situation of Example 3. [Figure 16] It is a diagram showing another attachment position of the fixed arm. [Figure 17] It is a diagram showing the gripping operation by the conventional gripping device.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the gripping device according to the present invention and a work robot provided with the same will be described with reference to the drawings.

[0020] [First Embodiment] FIG. 1 is a diagram showing the gripping device 1A of the first embodiment and a work robot 10 for moving the gripping device 1A. The gripping device 1A of the first embodiment is for gripping an object 11. As shown in FIGS. 2 and 3, it includes a device main body 2 attached to the work robot10, a pair of gripping fingers 3, 3 pivotally supported on the device main body 2, an initial position return means 4 for returning each gripping finger 3 to the initial position, a reaction force conversion means 5 for receiving the reaction force when pressed against the object 11 and converting it into a force for rotating each gripping finger 3 to the gripping position, and a gripping state holding means 6 for holding the gripping fingers 3 in the state of gripping the object 11. Hereinafter, each configuration will be described.

[0021] The device body 2 is the main body of the gripping device 1A. In this first embodiment, as shown in Figures 2 and 3, the device body 2 has a mounting portion 21 that can be attached to the work robot 10 and is configured to be detachable. In this invention, the work robot 10 is not limited to the robot arm type shown in Figure 1, but includes all robots that move the gripping device 1A to perform work. For example, it may be an orthogonal robot that combines two or three orthogonal sliding axes with a single-axis actuator to enable two-dimensional or three-dimensional movement.

[0022] The gripping fingers 3 are for gripping the object 11. In this first embodiment, as shown in Figures 2 and 3, the gripping fingers 3 are provided in pairs on the left and right sides of the device body 2 and are pivotally supported together with the pivot shaft 31 so as to be rotatable. Furthermore, as shown in Figure 2, each gripping finger 3 is rotatable between an initial position open away from the object 11 and a gripping position closed toward the object 11, and when rotated to the gripping position, they are positioned to be close to each other.

[0023] Furthermore, in this first embodiment, as shown in Figures 2 and 3, each gripping finger 3 has a gripping finger side gear 32 provided on the pivot axis 31 and which rotates in conjunction with the rotation of the gripping finger 3; each gripping finger side gear 32 has a body side gear 34 provided and which is rotatably supported on the device body 2; each body side gear 35 is fixed coaxially with each body side gear 34; and a transmission member 33 transmits the rotational movement of each gripping finger side gear 32 to each body side gear 34.

[0024] Then, by meshing the synchronization gears 35 with each other, the rotational movement of one gripping finger 3 is transmitted to the other gripping finger 3, thus synchronizing them. Examples of transmission members 33 include timing belts and chains, and when a chain is used, a sprocket is used instead of the gripping finger side gear 32 and the main body side gear 34.

[0025] Furthermore, the number of gripping fingers 3 is not limited to one pair (two), but can be increased or decreased as appropriate. For example, if a fixed finger that is completely fixed to the device body 2 and cannot rotate is provided, and the gripping fingers 3 are positioned so that they are close to each other when rotated to the gripping position, then gripping is possible with one gripping finger 3 and the fixed finger. Alternatively, three or more gripping fingers 3 may be provided at equal intervals around the circumference to make it difficult for the gripped object 11 to fall. Even with three or more gripping fingers, if the synchronization mechanism described above is adopted and all the synchronization gears 35 are meshed with each other, the rotational movement of one gripping finger 3 will be transmitted to the other gripping fingers 3.

[0026] The initial position return means 4 returns each gripping finger 3 to its initial position. In this first embodiment, as shown in Figure 3, the initial position return means 4 is composed of a torsion spring provided around the pivot axis 31, and is designed to constantly apply a force to the gripping fingers 3 in the direction of the initial position. Note that the initial position return means 4 is not limited to a torsion spring; it may be made of rubber or other material that can constantly apply a force to the gripping fingers 3 in the direction of the initial position.

[0027] The reaction force conversion means 5 converts the reaction force when pressed against the object 11 into a force that rotates the gripping fingers 3. In this first embodiment, as shown in Figures 2 and 3, the reaction force conversion means 5 is composed of a gripping belt 51 fixed so as to be stretched between the tips of a pair of gripping fingers 3. The tension is set so that the moment applied to the gripping fingers 3 from the gripping belt 51 is greater than the moment applied to the gripping fingers 3 from the initial position return means 4.

[0028] With this configuration, as shown in Figure 4(a), when the gripping device 1A is moved (descended) toward the object 11, the gripping belt 51 is pressed against the object 11. Then, tension is generated in the gripping belt 51 due to the reaction force from the object 11, and as shown in Figure 4(b), the tips of each gripping finger 3 are pulled diagonally upward and rotated toward the gripping position. In other words, the gripping belt 51 receives the reaction force when pressed against the object 11 and converts it into a force that rotates the gripping fingers 3 toward the gripping position. Note that only the main components of the gripping device 1A are schematically shown in Figure 4.

[0029] Furthermore, in this first embodiment, both ends of the gripping belt 51 are fixed to the gripping fingers 3, as shown in Figure 2, and are fixed to the tips of fixed arms 52 that extend in the opposite direction from the pivot axis 31 of the gripping fingers 3 to the direction of the gripping position. With this configuration, the moment when the gripping fingers 3 rotate due to the gripping belt 51 receiving a reaction force increases in proportion to the length of the fixed arms 52, making it easier for the gripping fingers 3 to rotate.

[0030] Furthermore, the fixing point of the fixing arm 52 is not limited to the gripping fingers 3; the end of the gripping belt 51 can be fixed at a position away from the gripping belt 51 in a direction that increases the moment applied to the gripping fingers 3. Also, if the gripping fingers 3 can rotate sufficiently, both ends of the gripping belt 51 may be fixed to the tips of each gripping finger 3, etc.

[0031] Furthermore, in this first embodiment, the gripping belt 51 is formed in the shape of a strip of silicone rubber, but the configuration is not limited to this. Any material that can receive the reaction force when pressed against the object 11 and convert it into a force that rotates the gripping fingers 3 in the direction of the gripping position is acceptable. For example, multiple round belts made of polyurethane may be stretched side by side.

[0032] Furthermore, the reaction force conversion means 5 is not limited to the configuration of a gripping belt 51 stretched across the tip of the gripping finger 3. For example, as another example of the reaction force conversion means 5, as shown in Figure 5(a), a contact member 53 that is pressed against the object 11 is provided so as to be slidable vertically relative to the device body 2, and a coil spring is provided as the initial position return means 4. On the other hand, the gripping finger 3, which is pivotally supported relative to the device body 2, is integrally provided with a link portion 54 connected to the pin 53a and elongated hole 54a of the contact member 53.

[0033] With this configuration, as shown in Figure 5(b), when the contact member 53 is pressed against the object 11, the reaction force causes the contact member 53 to slide upward relative to the device body 2. As a result, the link portion 54 moves upward, causing each gripping finger 3 to rotate in the direction of the gripping position and grip the object 11. In other words, the contact member 53 and the link portion 54 can also receive the reaction force when pressed against the object 11 and convert it into a force that rotates the gripping fingers 3 in the direction of the gripping position.

[0034] However, in the other examples described above, the gripping device 1A must be lowered until the contact member 53, which is located at approximately the same height as the base end of the gripping finger 3, contacts the object 11. In contrast, with the reaction force conversion means 5 using the gripping belt 51, the gripping belt 51 contacts the object 11 and starts the gripping operation when the tip of the gripping finger 3 reaches a height position near the upper end of the object 11. Therefore, the object 11 can be gripped faster compared to the other examples, contributing to a reduction in cycle time.

[0035] The gripping state holding means 6 maintains the state in which the gripping finger 3, which has been rotated in the direction of the gripping position, is gripping the object 11. In this first embodiment, as shown in Figures 2 and 6, the gripping state holding means 6 has a sawtooth-shaped ratchet gear 61 provided on the pivot axis 31 of the gripping finger 3 and which rotates in conjunction with the rotation of the gripping finger 3, and a locking claw 62a that is rotatably provided on the device body 2 and which engages with the ratchet gear 61.

[0036] Furthermore, the locking claw 62a is provided at the lower end of the locking member 62, and the approximate center of this locking member 62 is pivotally supported by a pivot shaft 63 provided on the device body 2. A torsion spring 64 provided around the pivot shaft 63 applies a rotational force to the locking member 62 in the direction that the locking claw 62a engages with the ratchet gear 61. As a result, the locking claw 62a rotates the gripping finger 3 only in the direction of the gripping position and prevents rotation in the direction of the initial position.

[0037] With this configuration, as shown in Figure 6(a), when the gripping finger 3 receives a rotational force from the gripping belt 51 toward the gripping position, the ratchet gear 61 rotates without engaging with the locking claw 62a, causing the gripping finger 3 to rotate toward the gripping position. Then, when the gripping device 1A stops and the rotational force on the gripping finger 3 is lost, the initial position return means 4 attempts to cause the gripping finger 3 to rotate toward the initial position, but the locking claw 62a engages with the ratchet gear 61, preventing this rotation and maintaining the gripping state.

[0038] On the other hand, to release the gripping state by the gripping state holding means 6, as shown in Figure 6(b), the gripping device 1A is moved so that the upper end of the locking member 62 comes into contact with the tip of the release member 65, which is provided at a predetermined position. As a result, the locking member 62 rotates against the rotational force of the torsion spring 64, and the locking claw 62a disengages from the ratchet gear 61, thus releasing the lock. Then, the gripping finger 3 rotates towards the initial position by the initial position return means 4 and returns to the initial position shown in Figure 6(c). The release member 65 is installed near the position where the object 11 gripped by the gripping finger 3 is released, as shown in Figure 1.

[0039] In this first embodiment, since the rotational movements of each gripping finger 3 are synchronized, the gripping state holding means 6 is provided on only one of the gripping fingers 3. However, the configuration is not limited to this, and if each gripping finger 3 rotates independently and individually, it is necessary to provide a gripping state holding means 6 for each gripping finger 3. Also, in this first embodiment, a ratchet gear 61 and a locking pawl 62a are used as the gripping state holding means 6, but the configuration is not limited to this, and actuators such as an electromagnetic clutch, solenoid, or air cylinder may be used.

[0040] Next, the operation of the gripping device 1A of this first embodiment and the work robot 10 equipped therewith will be explained with reference to Figure 7. In Figure 7, as with Figure 4, only the main components of the gripping device 1A are schematically shown.

[0041] When gripping an object 11 using the gripping device 1A of this first embodiment, first, as shown in Figure 7(a), the work robot 10 moves the gripping device 1A to a position directly above the object 11 to be gripped. Next, when the work robot 10 moves (lowers) the gripping device 1A to a position where it can grip the object 11, the gripping belt 51 pressed against the object 11 receives a reaction force, which is converted into a force that rotates the gripping fingers 3 in the direction of the gripping position. As a result, as shown in Figure 7(b), each gripping finger 3 grips the object 11 at the same time that the movement of the gripping device 1A is completed.

[0042] In other words, according to the gripping device 1A of this first embodiment, the steps of moving (lowering) the object 11 to a position where it can be gripped and moving the gripping fingers 3 to grip the object 11, which were performed individually in the conventional gripping operation (Figure 17), are performed simultaneously. Therefore, the object 11 can be gripped at a higher speed compared to the conventional gripping operation, shortening the cycle time and improving productivity. Furthermore, since the gripping operation is performed solely by a mechanical mechanism and does not require actuators such as motors or air cylinders, it is suitable for use in outdoor environments where it is difficult to use electricity or pneumatics, or for use mounted on work vehicles where it is desirable to reduce power consumption as much as possible due to limitations in electrical capacity.

[0043] Furthermore, in this first embodiment, a gripping belt 51 stretched across the tip of the gripping finger 3 is used as the reaction force conversion means 5. With this configuration, the gripping belt 51 makes contact with the object 11 at an earlier timing and starts the gripping operation, further improving the gripping speed. In addition, when the gripping finger 3 is gripping the object 11, as shown in Figure 7(b), the gripping belt 51 holds the object 11 in a way that wraps around it, making it difficult to damage the object 11 and preventing it from being dropped.

[0044] Furthermore, in this first embodiment, the fixed arm 52 fixes both ends of the gripping belt 51 at a position away from the pivot axis 31 of the gripping finger 3 in the opposite direction to the gripping position. As a result, the moment when rotating the gripping finger 3 is increased, allowing the gripping finger 3 to rotate quickly and reliably. In addition, since the pair of gripping fingers 3, 3 are synchronized by the gripping finger side gear 32, the transmission member 33, the main body side gear 34, and the synchronization gear 35, even if the object 11 contacts the object at an off-center position from the center of the gripping belt 51, each gripping finger 3 rotates by the same angle to reliably grip the object 11.

[0045] After the gripping device 1A grips the object 11, the work robot 10 moves the object 11 together with the gripping device 1A to the desired position, as shown in Figure 7(c). In this first embodiment, as shown in Figure 1, a release member 65 is provided at the desired position. Therefore, the work robot 10 simply brings the upper end of the locking member 62 into contact with the tip of the release member 65, causing the locking claw 62a to disengage from the ratchet gear 61 and release the lock. As a result, the initial position return means 4 rotates each gripping finger 3 towards the initial position, releasing the object 11.

[0046] As described above, in this first embodiment, a ratchet gear 61 and a locking pawl 62a are used as the gripping state holding means 6. Therefore, not only the gripping operation but also the holding and release of the gripping state are all realized by mechanical mechanisms alone, and no actuators are required. Consequently, it is possible to completely eliminate the power supply for the gripping device 1A and reduce power consumption to zero.

[0047] According to the first embodiment described above, the following effects are achieved. 1. By gripping the object 11 at high speed, the cycle time can be shortened and productivity can be improved. 2. By employing the gripping belt 51 as the reaction force conversion means 5, the gripping speed can be further improved by making contact with the object 11 at an earlier timing and initiating the gripping operation. 3. By fixing both ends of the gripping belt 51 in the positions described above, the moment when rotating the gripping finger 3 is increased, allowing the gripping finger 3 to be rotated quickly and reliably. 4. By synchronizing each gripping finger 3, even if the object 11 makes contact with the gripping belt 51 at an off-center position, each gripping finger 3 can be rotated by the same angle to securely grip the object 11. 5. By employing a ratchet gear 61 and a locking pawl 62a as means for maintaining the gripping position, the gripping device 1A can be made power-free and power consumption can be reduced to zero.

[0048] [Second Embodiment] Next, a gripping device 1B according to a second embodiment of the present invention will be described. Note that components of this second embodiment that are the same as or equivalent to those of the first embodiment described above are denoted by the same reference numerals, and further explanation is omitted.

[0049] The features of this second embodiment are that it has an inter-finger distance adjustment mechanism 7 that can adjust the distance between the gripping fingers 3 while maintaining a synchronized state between the gripping fingers 3, and that each gripping finger 3 has multiple joints.

[0050] Specifically, as shown in Figures 8 to 10, the finger spacing adjustment mechanism 7 includes a device body 2 which comprises left and right guide members 71 that support the gripping fingers 3 so that they can slide in the left and right directions, a vertical movement member 73 that moves up and down to allow the gripping fingers 3 to slide in the left and right directions, a link member 72 whose one end is rotatably attached to the gripping fingers 3 and whose other end is rotatably attached to the vertical movement member 73, and a vertical guide member 74 that supports the vertical movement member 73 so that it can slide in the vertical direction. The vertical movement member 73 can be fixed to the vertical guide member 74 at a desired height position.

[0051] Furthermore, in this second embodiment, a synchronization mechanism is provided, similar to the first embodiment. Specifically, as shown in Figures 8 and 9, the second joint shaft 305 corresponds to the pivot shaft 31, and a gripping finger-side gear 32 is provided on this second joint shaft 305, which rotates in conjunction with the rotation of the middle joint portion 302 (gripping finger 3). Also, the vertical movement member 72 corresponds to the device body 2, and a synchronization gear 35, fixed coaxially with each body-side gear 34, is provided on this vertical movement member 72 so as to be rotatable while meshing with each other. The gripping finger-side gear 32 and the body-side gear 34 transmit rotational motion via a transmission member 33.

[0052] Furthermore, in this second embodiment, as shown in Figures 8 and 9, one end of the link member 72 is rotatably mounted on the pivot axis of the gripping finger side gear 32, and the other end of the link member 72 is rotatably mounted on the pivot axes of the main body side gear 34 and the synchronization gear 35.

[0053] With the above configuration, in the state shown in Figure 11(b), when the vertical movement member 73 is moved upward along the vertical guide member 74, as shown in Figure 11(a), the gripping fingers 3 are pulled by the link member 72 and move toward the gripping position while the synchronous gear 35 remains engaged, and the distance between the fingers narrows. On the other hand, in the state shown in Figure 11(b), when the vertical movement member 73 is moved downward along the vertical guide member 74, as shown in Figure 11(c), the gripping fingers 3 are pushed by the link member 72 and move toward the initial position while the synchronous gear 35 remains engaged, and the distance between the fingers widens.

[0054] Furthermore, since the synchronization between the gripping fingers 3 is maintained even after adjusting the distance between the fingers, the rotational movement of one gripping finger 3 (the middle joint portion 302 described later) is transmitted in the following order: gripping finger side gear 32, transmission member 33, main body side gear 34, and synchronization gear 35. Then, it is transmitted in the following order: synchronization gear 35 on the other gripping finger 3 side, main body side gear 34, transmission member 33, and gripping finger side gear 32, causing the other gripping finger 3 (middle joint portion 302) to rotate in synchronization.

[0055] Therefore, according to the finger distance adjustment mechanism 7 of this second embodiment, it is possible to grip various objects 11 by adjusting the finger distance according to the size of the object 11. Furthermore, by providing a synchronization gear 35 on the vertically moving member 73 for adjusting the finger distance, the finger distance adjustment mechanism 7 and the synchronization mechanism are coupled, so that the finger distance can be adjusted while maintaining the synchronized state between each gripping finger 3.

[0056] However, when the finger spacing is adjusted, the tension on the gripping belt 51 also changes, so it is necessary to adjust the length of the gripping belt 51 as appropriate to maintain a constant tension. This adjustment may be done manually, or it may be automatically adjusted by installing a tension sensor on the gripping belt 51 and winding or unwinding the end of the gripping belt 51 with a motor or the like based on its output value. Alternatively, the tension of the gripping belt 51 may be kept constant by a mechanical mechanism such as an auto-tensioner.

[0057] Furthermore, in this second embodiment, the finger-to-finger distance adjustment mechanism 7 and the synchronization mechanism are combined to allow adjustment of the finger-to-finger distance while maintaining synchronization between each gripping finger 3. However, the configuration is not limited to this, and if it is not necessary to synchronize each gripping finger 3, only the finger-to-finger distance adjustment mechanism 7 may be provided without a synchronization mechanism, and the finger-to-finger distance of each gripping finger 3 may be adjusted.

[0058] In this second embodiment, the finger spacing adjustment mechanism 7 is configured such that when the vertical movement member 73 is moved upward, the gripping fingers 3 move in the direction of the gripping position, and when the vertical movement member 73 is moved downward, the gripping fingers 3 move in the direction of the initial position. However, the configuration is not limited to this, and a slider-crank mechanism or the like may be used so that when the vertical movement member 73 is moved upward, the gripping fingers 3 move in the direction of the initial position, and when the vertical movement member 73 is moved downward, the gripping fingers 3 move in the direction of the gripping position. In other words, the finger spacing adjustment mechanism 7 is configured such that when the vertical movement member 73 is moved up and down along the vertical guide member 74, the gripping fingers 3 move left and right along the left and right guide member 71 via the link portion 54.

[0059] Furthermore, in this second embodiment, the finger distance adjustment mechanism 7 moves the vertically moving member 73 manually, but the configuration is not limited to this, and it may be driven using an actuator such as a motor or air cylinder. This makes it possible to perform the conventional gripping operation (Figure 17) by removing the gripping belt 51 and changing the finger distance. Therefore, when high-speed gripping is desired, the gripping operation mode according to the present invention is used, and when processing speed is not required and extremely small or thin objects are to be gripped, the conventional gripping operation mode is used, allowing for two different uses.

[0060] Furthermore, in this second embodiment, since the vertically moving member 73 moves up and down along the vertically moving guide member 74, the position of the vertically moving member 73 is uniquely determined when the distance between fingers is determined. However, the configuration is not limited to this, and the vertically moving member 74 does not necessarily have to be provided. This is because if the gripping fingers 3 are directly fixed to the left and right guide members 71 after adjusting the distance between fingers, there is no need to fix the vertically moving member 73 to the vertically moving guide member 74.

[0061] Furthermore, in this second embodiment, as shown in Figures 8 to 10, each gripping finger 3 is composed of a distal phalange 301 at the tip, an intermediate phalange 302, and a proximal phalange 303 provided on the device body 2. It also has a first joint axis 304 that rotatably connects the distal phalange 301 and the intermediate phalange 302, and a second joint axis 305 that rotatably connects the intermediate phalange 302 and the proximal phalange 303.

[0062] Furthermore, in this second embodiment, the configuration for linking the joints together includes a first gear 306 provided around the first joint axis 304 and rotating together with the end section 301, a second gear 307 provided around the second joint axis 305 and fixed to the base section 303, an intermediate gear 308 rotatably supported on the middle section 302 in a state of meshing with the second gear 307 and rotating in conjunction with the rotation of the middle section 302 relative to the base section 303, a transmission gear 309 fixed coaxially with the intermediate gear 308, and a transmission belt 310 that transmits the rotational movement of the transmission gear 309 to the first gear 306, causing the end section 301 to rotate.

[0063] With this configuration, as shown in Figure 12(a), when the gripping belt 51 receives a reaction force from the object 11 (S1), a force is applied to the tip of the gripping finger 3 that rotates it in the direction of the gripping position. Due to this rotational force, the middle section 302 rotates in the direction of the gripping position with respect to the second joint axis 305, and because the intermediate gear 308 is meshed with the second gear 307 fixed to the base section 303, it rotates counterclockwise in Figure 12 (S2). The rotational force of the transmission gear 309, which rotates integrally with the intermediate gear 308, is transmitted to the first gear 306 by the transmission belt 310 (S3), so the first gear 306 rotates counterclockwise in Figure 12 (S4).

[0064] As a result, the end section 301, which rotates integrally with the first gear 306, rotates, causing the middle section 302 to rotate toward the gripping position relative to the second joint axis 305, as shown in Figure 12(b). In conjunction with this rotation, the end section 301 also rotates toward the gripping position relative to the first joint axis 304. Therefore, the end section 301 bends so as to fit beneath the object 11, making it easier to grip an object 11 placed on a flat surface.

[0065] In this second embodiment, each gripping finger 3 has two joints, but the configuration is not limited to this, and it may have three or more joints. In this case, each gripping finger 3 is composed of at least a distal phalanx 301, a middle phalanx 302, and a proximal phalanx 303, and the number of phalanges will increase according to the number of joints.

[0066] Furthermore, in this second embodiment, the gear ratio of the transmission gear 309 and the first gear 306 is set to 1:1, so the amount of rotation of the middle section 302 relative to the base section 303 matches the amount of rotation of the end section 301 relative to the middle section 302. However, the configuration is not limited to this, and the degree of bending of the end section 301 can be adjusted by appropriately setting the gear ratio.

[0067] The gripping device 1B and the work robot 10 equipped therewith of this second embodiment provide the following additional effects in addition to the effects of the first embodiment described above. 1. The finger distance adjustment mechanism 7 allows for easy adjustment of the distance between the gripping fingers 3, enabling the gripping of objects 11 of various sizes. 2. By connecting the inter-finger distance adjustment mechanism 7 with the synchronization mechanism, the inter-finger distance can be adjusted while maintaining the synchronized state between each gripping finger 3. 3. By providing the gripping fingers 3 with multiple joints, it becomes easier to grip objects 11 that are placed on a flat surface.

[0068] Next, specific embodiments of the gripping devices 1A and 1B according to the present invention and the work robot 10 equipped therewith will be described. It should be noted that the technical scope of the present invention is not limited to the features shown in the following embodiments. [Examples]

[0069] In this embodiment 1, an experiment was conducted to confirm how much faster the gripping operation by the gripping device 1A of the first embodiment is compared to the conventional gripping operation (Figure 17).

[0070] In this embodiment 1, the collaborative robot UR5e (Universal Robots) was used as the work robot 10. Furthermore, the Adaptive Gripper (ROBOTIQ) was used as the device for performing conventional gripping operations.

[0071] As shown in Figure 13, the object 11 consisted of eggplants, carrots, and cucumbers placed on a workbench at predetermined intervals. The processing time was measured from when the gripping device 1A was stationary until it gripped an eggplant and released it, then a carrot and released it, and finally a cucumber and released it.

[0072] As a result, while it took 24.6 seconds with a conventional gripping device, the time was reduced to 20.2 seconds with the gripping device 1A of this first embodiment.

[0073] This embodiment 1 demonstrates that the gripping device 1A of this first embodiment can grip the object 11 at high speed. [Examples]

[0074] In this second embodiment, an experiment was conducted to confirm how much faster the gripping operation by the gripping device 1B of the second embodiment is compared to the conventional gripping operation (Figure 17).

[0075] In this second embodiment, as in the first embodiment, a collaborative robot UR5e (Universal Robots) was used as the work robot 10. Furthermore, an electric gripper, Adaptive Gripper (ROBOTIQ), was used as the device for performing conventional gripping operations.

[0076] As shown in Figure 14, a sweet potato was placed on a workbench as the object 11. The processing time was measured from when the gripping device 1B was stationary until it gripped the sweet potato and released it at the release position. As a result, while it took 8.1 seconds with the conventional gripping device, it was reduced to 6.9 seconds with the gripping device 1B of this second embodiment.

[0077] This embodiment 2 demonstrates that the gripping device 1B of this second embodiment can grip the object 11 at high speed. [Examples]

[0078] In this third embodiment, an experiment was conducted to confirm whether the gripping device 1B of the second embodiment could grip objects 11 of various sizes.

[0079] In this third embodiment, as in embodiments 1 and 2, a collaborative robot UR5e (Universal Robots) was used as the work robot 10. Furthermore, an electric gripper, Adaptive Gripper (ROBOTIQ), was used as the device for performing conventional gripping operations.

[0080] The objects 11 prepared were burdock root, carrots, sweet potatoes, and cut pumpkins. The finger spacing adjustment mechanism 7 was used to adjust the distance between the gripping fingers 3 as appropriate, and then the gripping action was performed. As a result, as shown in Figure 15, it was confirmed that all of the objects 11 were firmly gripped.

[0081] According to this embodiment 3 described above, the gripping device 1B of this second embodiment can firmly grip various objects 11 by adjusting the distance between the gripping fingers 3 using the finger distance adjustment mechanism 7.

[0082] Furthermore, the gripping device and the work robot equipped therewith according to the present invention are not limited to the embodiments described above and can be modified as appropriate.

[0083] For example, in the embodiments described above, the fixed arm 52 was fixed to the gripping finger 3, but the configuration is not limited to this. Specifically, as shown in Figure 16, the fixed arm 52 may be fixed directly to the synchronous gear 35, or fixed so as to rotate in conjunction with the rotation of the synchronous gear 35 on the same pivot axis as the synchronous gear 35. With this configuration, the protruding width of the fixed arm 52 is reduced compared to when it is fixed to the gripping finger 3, thus reducing the risk of contact with surrounding objects or people.

[0084] Furthermore, when the fixed arm 52 is fixed to the gripping finger 3, the amount of rotation of the gripping finger 3 is determined by the size of the object 11. On the other hand, when the fixed arm 52 is fixed to rotate coaxially with the synchronization gear 35, even if the object 11 is small relative to the distance between the fingers, the gripping finger 3 can rotate sufficiently by adjusting the gear ratio between the gripping finger side gear 32 and the main body side gear 34, making it easier to grip. [Explanation of Symbols]

[0085] 1A Gripping device (first embodiment) 1B Gripping device (second embodiment) 2. Main unit of the device 21 Mounting part 3 Grasping fingers 31. Rotating shaft 32 Grip finger side gear 33 Transmission member 34 Main unit gear 35 Synchronization gear 301 Distal segment 302 Middle segment 303 Proximal phalanx 304 First joint axis 305 Second joint axis 306 First Gear 307 Second gear 308 Intermediate gear 309 Transmission Gear 310 Transmission belt 4. Means for returning to the initial position 5. Reaction force conversion means 51 Gripping belt 52 Fixed Arm 53 Contact Member 53a pin 54 Link section 54a long hole 6 Gripping state holding means 61 Ratchet Gear 62 Locking member 62a Locking claw 63 Rotary shafts 64 Torsion spring 65 Release Member 7 Finger distance adjustment mechanism 71 Left and right guide members 72 Link members 73 Vertical movement member 74 Upper and lower guide members 10 Industrial Robots 11. Object

Claims

1. A gripping device for gripping an object, A device body attached to a work robot that moves the aforementioned gripping device, A gripping finger is provided on the main body of the device and is pivotally supported so as to be rotatable between an initial position that is open away from the object and a gripping position that is closed toward the object. An initial position return means that constantly applies a force to the gripping finger to return it to the initial position, A reaction force conversion means that receives the reaction force when pressed against the object and converts it into a force that rotates the gripping finger in the direction of the gripping position, A gripping state holding means that maintains the state in which the gripping finger, which has been rotated in the direction of the gripping position, is gripping the object, A gripping device having the following features.

2. The main body of the aforementioned device is Left and right guide members that support the gripping fingers so that they can slide in the left and right directions, A vertically moving member that moves up and down to slide the gripping finger in the left-right direction, A link member having one end rotatably attached to the gripping finger and the other end rotatably attached to the vertically moving member, It has, The gripping device according to claim 1, wherein when the vertically moving member is moved up and down, the gripping fingers move in the left-right direction along the left-right guide members via the link member.

3. The gripping finger is composed of at least a distal phalanx at the tip, an intermediate phalanx, and a proximal phalanx provided on the main body of the device. A first joint axis that rotatably connects the distal portion and the middle portion, A second joint shaft that rotatably connects the aforementioned middle section and the aforementioned base section, A first gear is provided around the first joint axis and rotates together with the distal section, A second gear is provided around the second joint axis and fixed to the base portion, An intermediate gear is pivotally supported on the middle section in a state where it meshes with the second gear, and rotates in conjunction with the rotation of the middle section relative to the base section. A transmission gear fixed coaxially with the aforementioned intermediate gear, A transmission belt that transmits the rotational motion of the transmission gear to the first gear and rotates the end section, A gripping device according to claim 1 or claim 2, having the following features.

4. The gripping finger is positioned such that, when rotated to the gripping position, it approaches other gripping fingers or fixed fingers that cannot rotate. The gripping device according to claim 3, wherein the reaction force conversion means is comprised of a gripping belt fixed so as to be stretched between the tip of the gripping finger and the tip of another gripping finger or the fixing finger.

5. Multiple gripping fingers are provided. A gripping finger-side gear is provided on the pivot axis of each gripping finger and rotates in conjunction with the rotation of the gripping finger, A gear is provided for each gripping finger side gear, and a main body side gear is pivotally supported on the main body of the device, A synchronization gear fixed coaxially with each main unit gear, A transmission member that transmits the rotational movement of each gripping finger-side gear to each main body-side gear, It has, The gripping device according to claim 4, wherein all of the aforementioned synchronization gears are meshed with each other so that the rotational movement of one gripping finger is transmitted to the other gripping fingers.

6. The main body of the aforementioned device is Left and right guide members that support the gripping fingers so that they can slide in the left and right directions, A vertically moving member that moves up and down to slide the gripping finger in the left-right direction, A link member having one end rotatably attached to the gripping finger and the other end rotatably attached to the vertically moving member, It has, The vertically moving member is provided with the synchronization gears, which are fixed coaxially with each main body gear, and are rotatably mounted in a state where they mesh with each other. One end of the link member is rotatably mounted on the pivot shaft of the gripping finger side gear, and the other end of the link member is rotatably mounted on the pivot shafts of the main body side gear and the synchronization gear. The gripping device according to claim 5, wherein when the vertically moving member is moved up and down, the gripping fingers move in the left-right direction along the left-right guide members via the link member while maintaining a synchronized state between each gripping finger.

7. The gripping device according to claim 6, further comprising a fixing arm for fixing the end of the gripping belt at a position away from the gripping belt in a direction that increases the moment applied to the gripping finger.

8. The gripping device according to claim 7, wherein the fixed arm is fixed so as to rotate in conjunction with the rotation of the synchronous gear, with respect to the same pivot axis as the synchronous gear.

9. The gripping position holding means includes: A sawtooth-shaped ratchet gear is provided on the pivot axis of the gripping finger and rotates in conjunction with the rotation of the gripping finger, A locking claw engages with the ratchet gear, allowing the gripping finger to rotate only in the direction of the gripping position and preventing rotation in the direction of the initial position, The gripping device according to claim 8, having the following features.

10. The gripping finger is positioned such that, when rotated to the gripping position, it approaches other gripping fingers or fixed fingers that cannot rotate. The gripping device according to claim 1 or 2, wherein the reaction force conversion means is comprised of a gripping belt fixed so as to be stretched between the tip of the gripping finger and the tip of another gripping finger or the fixing finger.

11. Multiple gripping fingers are provided. A gripping finger-side gear is provided on the pivot axis of each gripping finger and rotates in conjunction with the rotation of the gripping finger, A gear is provided for each gripping finger side gear, and a main body side gear is pivotally supported on the main body of the device, A synchronization gear fixed coaxially with each main unit gear, A transmission member that transmits the rotational movement of each gripping finger-side gear to each main body-side gear, It has, The gripping device according to claim 1 or 2, wherein all of the aforementioned synchronization gears are meshed with each other so that the rotational movement of one gripping finger is transmitted to the other gripping fingers.

12. The main body of the aforementioned device is Left and right guide members that support the gripping fingers so that they can slide in the left and right directions, A vertically moving member that moves up and down to slide the gripping finger in the left-right direction, A link member having one end rotatably attached to the gripping finger and the other end rotatably attached to the vertically moving member, It has, The vertically moving member is provided with the synchronization gears, which are fixed coaxially with each main body gear, and are rotatably mounted in a state where they mesh with each other. One end of the link member is rotatably mounted on the pivot shaft of the gripping finger side gear, and the other end of the link member is rotatably mounted on the pivot shafts of the main body side gear and the synchronization gear. The gripping device according to claim 11, wherein when the vertically moving member is moved up and down, the gripping fingers move in the left-right direction along the left-right guide members via the link member while maintaining the synchronized state between each gripping finger.

13. The gripping device according to claim 1 or claim 2, further comprising a fixing arm for fixing the end of the gripping belt at a position away from the gripping belt in a direction that increases the moment applied to the gripping finger.

14. The gripping device according to claim 13, wherein the fixed arm is fixed so as to rotate in conjunction with the rotation of the synchronous gear, with respect to the same pivot axis as the synchronous gear.

15. The gripping position holding means includes: A sawtooth-shaped ratchet gear is provided on the pivot axis of the gripping finger and rotates in conjunction with the rotation of the gripping finger, A locking claw engages with the ratchet gear, allowing the gripping finger to rotate only in the direction of the gripping position and preventing rotation in the direction of the initial position, A gripping device according to claim 1 or claim 2, having the following features.

16. A work robot equipped with the gripping device described in claim 1.

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