JPH0627347Y2 - Robot hand - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention is equipped with a copying mechanism for workpieces which are attached to an arm of a robot and which are randomly arranged in a non-uniform posture. The present invention relates to a robot hand which holds a work by means such as a mechanical means.

2. Description of the Related Art Japanese Patent Application No. 62-9739 discloses a robot hand capable of following the posture of a grasping part to follow the posture of a workpiece.
There is one described in the issue.

In this robot hand, a work piece having a shape in which the tip side for gripping a work is formed to match the shape of the work is mounted between the U-shaped left and right supports so as to be slidable in the vertical direction and rotatable in the front-back direction. A work copying tactile sensation for making the work contact metal imitate the work is provided so as to extend in the front-rear direction from the work contact metal. This robot hand is used by being attached to the tip of the arm of the robot. Further, a robot having this robot hand attached to the tip of an arm picks up an image of a work group piled up in a pallet with an upper TV camera, processes the image, and determines the position and orientation of the work that can be taken out by the robot hand. Each data is input and the work is automatically grasped, and the posture of the grasped work is corrected to a predetermined posture and supplied to the manufacturing line or the like. However, in the data of the position and orientation of the work obtained by picking up the work from above with the television camera as described above, there is insufficient data on the tilt of the work in the vertical direction. When automatically gripping a work, it is often the case that the posture of the work gripping part is automatically gripped by following the inclination of the gripping work. In the case of the robot hand, the work gripping the work. The back metal is mounted between the left and right supports so that it can slide in the vertical direction and can rotate in the front-back direction, and when the work is gripped, the work contact metal touches the work in a tilted position to rotate the work contact. Then, the work piece is tilted according to the inclination of the work in the longitudinal direction, and the work is gripped from both side directions orthogonal to the longitudinal direction.

However, in the case of the above-mentioned conventional robot hand, the work copying haptic is extended in the front-back direction from the work pad provided so as to be rotatable in the front-back direction, and The structure that contacts the work on the outside of the work piece to be gripped makes it suitable for automatic gripping of relatively short work, but when gripping a long work, the work gripping part As the length of the work becomes longer, both ends of a long work cannot be gripped, which causes inconvenience such as an unstable gripping state.

Further, as a robot hand having a structure suitable for gripping both ends of a long work, there is one shown in FIG.

The robot hand 1 holds a long and uneven work such as a crankshaft of an automobile engine. The hand body 2 holds the work W and the hand body 2 is attached to an arm (not shown) of the robot. The robot mounting portion 3 is connected via a link 4, and a pair of gripping claws 5, 5 for mechanically gripping the work W are provided on the lower surface side of the hand body 2 in the longitudinal direction of the hand body 2. A pair of copying guides 6 and 6 are provided rotatably supported by support shafts 5a horizontally provided at both ends of the hand body 2 in a direction orthogonal to the longitudinal direction, and at a substantially equal distance from the center of the hand body 2. , Are provided so as to project downward from positions separated from each other. The both gripping claws 5 and 5 are adapted to be opened and closed by an opening and closing drive cylinder 9 provided in an upper part near the center of the hand body 2.

On the other hand, the link 4 is a rectangular plate-shaped body, and a guide hole 4a, which is a long hole, is formed on the upper end side in the longitudinal direction, and a pin hole (not shown) is formed on the lower end side.

Further, the hand body 2 is horizontally arranged in a pin hole provided at the lower end side of the link 4 at a position at the center of the hand body 2 in the longitudinal direction and higher than the center of gravity, in a direction perpendicular to the longitudinal direction. The lower connecting pin 7 provided in the lower connecting pin 7 is inserted into the lower connecting pin 7 from both sides, and the lower connecting pin 7 is rotatably connected while preventing the lower connecting pin 7 from swinging in the axial direction.
The robot mounting portion 3 and the upper end side of the link 4 are provided with an upper connecting pin 8 provided in the center of the lower portion of the robot mounting portion 3 in parallel with the lower connecting pin 7 in a long hole of the link 4. It is inserted through a certain guide hole 4a so as to be rotatable and movable in the vertical direction, and the upper end side of the link 4 is sandwiched from both sides to prevent the upper connecting pin 8 from swinging in the axial direction and are connected. Therefore, the hand body 2 is
With the robot hand 1 attached to the arm tip of the robot so as to hang down, the robot hand 1 is attached so as to be rotatable about the lower connecting pin 7 and the upper connecting pin 8 as fulcrums and movable in the vertical direction. .

Then, when gripping the work W selected from the work group randomly arranged on the pallet, the robot hand 1 in a state in which both gripping claws 5 and 5 are opened by the claw opening / closing cylinder 9 is input. Based on the data on the position and orientation of the work W, the work W is moved right above the work W, and the longitudinal direction of the work W is aligned with the longitudinal direction of the hand body 2, and then the work body 2 is lowered and moved upward to the work W. Approach from. Then, one of the pair of copying guides 6 and 6 projecting downward from the hand body 2 first comes into contact with the height side of the upper surface of the work W in an inclined posture and its lowering is regulated, and then the upper portion. In a state where the connecting pin 8 is allowed to move in the direction of approaching the hand body 2 in the guide hole 4a, which is a long hole, the hand body 2 rotates by its own weight around the lower connecting pin 7 and the upper connecting pin 8 as fulcrums. The hand body 2 tilts by moving, and tilts until the other copying guide 6 contacts the lower side of the upper surface of the work W, and the hand body 2 follows the tilt of the work W. Then, when it is detected that both of the copying guides 6 and 6 come into contact with the work W, the claw opening / closing cylinder 9 is actuated to drive both gripping claws 5 and 5 to close the work W in the longitudinal direction. It is designed to be gripped from both ends.

Then, the hand main body 2 holding the work W ascends and lifts the work W above the pallet, and the lower connecting pin 7 and the upper connecting pin 8 are fulcrum by the own weight of the work W and the own main body. As a result, the workpiece W is rotated to a position where the gripped state is horizontal. The robot holding the work W horizontally by the robot hand 1 raises the robot hand 1 to a predetermined height and then moves the work in the horizontal direction so that the work W held by the hand body 2 is moved to a predetermined position on an engine manufacturing line or the like. It is programmed to transfer the workpiece W to the position, release the grasping by the grasping claws 5, 5, and place the work W on the conveyor or the workbench in a predetermined posture.

However, in the case of the robot hand 1 described above, when the hand body 2 is made to follow the inclination of the work W, the hand body 2
In order to perform the copying operation of the hand main body 2 by tilting only by its own weight, the contact resistance between the copying guides 6 and 6 and the work W hinders the complete copying operation, resulting in defective copying. There was a risk of failing to grip W. Further, since the hand body 3 is suspended by the link 4, when the work W is transported, the hand body 2 holding the work W swings about the lower connecting pin 7 and the upper connecting pin 8 as a fulcrum, There is a problem that an excessive load is applied to the robot, and it takes time for the shake to subside once it starts to shake.

The present invention has been made in view of the above problems, and an object thereof is to provide a robot hand that enables an accurate copying operation of the hand body with respect to a work posture and prevents the hand body from shaking.

Means for Solving the Problems As a means for solving the above problems, the present invention provides a hand main body for holding a work, and a robot mounting portion for mounting the hand main body on an arm of a robot. In a robot hand connected so as to be able to follow a posture, a connecting member that connects the hand body and the robot mounting portion is formed by pins inserted with their axes parallel to each other. Rotatably connected to each other, and one of the pin connecting portions is configured to be movable in the linear direction connecting the pins, and further, the hand body is elastically urged in a direction away from the robot mounting portion. And an elastic urging means such as an actuator or a spring capable of changing the urging force at least in two ways. The position on the hand main body and the position on the robot mounting part that are on the straight line and outside each of the pin connecting portions are set as the pressing points, and the rotation of each pin connecting portion is allowed between the pressing points. It is characterized by being provided in support.

With the above-mentioned configuration, the elastic biasing means provided between the two pin connecting portions with the outer positions of the two pin connecting portions as the pressing points, the two pressing points being the most distant from each other,
That is, both pin connecting portions and both pressing points of the elastic biasing means are aligned in a straight line and are elastically biased in the direction in which the hand body is horizontal.

Therefore, during the copying operation of the hand main body, the copying ability of the hand main body is enhanced by the elastic biasing force, and the hand main body can accurately follow the posture of the work. In that case, since the pins connecting the connecting member to the hand body and the robot mounting portion are inserted so that their axes are parallel to each other, the hand body extends along the radial direction of these pins. Since the hand is rotated (or swung) only within the plane, it is possible to prevent the hand body from being in an unexpected direction due to the reaction force from the work.

Further, during non-copying operation of the hand body such as during work transfer, when the hand body rotates about each of the connecting pins as a fulcrum, the distance between the pressing points is shortened, so that the hand body is always horizontal. As described above, when the elastic biasing means elastically biases and the hand body tilts and the horizontal state collapses, the elastic biasing means is compressed and the elastic biasing force increases so that the hand body returns to the horizontal state. To prevent the hand body from swinging. Further, when the urging force is further strengthened and the shake of the hand main body is stopped, since the hand main body is in a horizontal state, it is possible to automatically maintain a so-called normal posture.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. The same components as those of the conventional robot hand shown in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

1 to 3 show a first embodiment of the present invention, in which a robot hand 11 mounts a hand body 2 for holding a work W and the hand body 2 on an arm (not shown) of the robot. The robot mounting portion 3 is connected via a link 4, and a pair of gripping claws 5 and 5 which are driven to open and close by an opening and closing drive cylinder 9 are provided on the lower surfaces of both ends of the hand body 2 by means of spindles 5a and 5a. A pair of copying guides 6 and 6 are provided rotatably near the center of the hand body 2 so as to project downward from positions separated from each other. Sensors 6a for detecting the approach or contact of the scanning guide 6 are provided respectively. A guide hole 4a is formed on the upper end side of the link 4, and a pin hole 4b (see FIG. 2) is formed on the lower end side thereof.

Further, the hand body 2 and the robot mounting portion 3 can be rotated to the lower end side of the link 4 by the lower connecting pin 7 inserted into the pin hole 4b at a position at the center of the hand body 2 in the longitudinal direction and higher than the center of gravity. The robot mounting portion 3 is rotatably and vertically movable to the upper end side of the link 4 by the upper connecting pin 8 inserted into the guide hole 4a at the lower center of the robot mounting portion 3. In the state where the robot mounting portion 3 of the robot hand 11 is mounted so as to hang down on the arm tip of the robot, the hand body 2 rotates with the lower connecting pin 7 and the upper connecting pin 8 as fulcrums, respectively. The movement of the upper connecting pin 8 is permitted by the guide hole 4a and the movement of the upper connecting pin 8 in the vertical direction. It should be noted that these connecting pins 7 and 8 are inserted so that their axes are parallel to each other as shown in the figure, and therefore the hand body 2
The rotation (or swinging) of the connecting pins 7 and 8 occurs only in the plane of the connecting pins 7 and 8 along the radial direction.

Further, on one side surface of the hand body 2 (a side surface on the front side in FIG. 1), a cylinder support shaft 12 vertically lowers the lower connecting pin 7 connecting the hand body 2 to the link 4. It is provided so that one end thereof is fixed in the vicinity and horizontally protrudes from the one side surface and is parallel to the axis of the lower connecting pin 7, and similarly, one side surface of the robot mounting portion 3 (front side in FIG. 1). On the side surface), the cylinder support shaft 13 has one end fixed in the vicinity of the upper side in the vertical direction of the upper connecting pin 8 connecting the robot mounting portion 3 to the link 4, and projects horizontally from the one side surface. It is provided so as to be parallel to the axis of the upper connecting pin 7. An air cylinder 14 is provided between the tips of the cylinder support shafts 12 and 13 to support the rear end of the cylinder of the air cylinder 14 at the tip of the one cylinder support shaft 13 located above the cylinder support shaft. The air cylinder 1 is mounted so as to be rotatable in a direction perpendicular to the shaft 13.
Similarly, the tip end of the cylinder rod 14a of No. 4 is rotatably attached to the tip end of the other cylinder support shaft 12 located below, and the air cylinder 14 generates a pressure switchable air pressure. Air is supplied from a source (not shown) through the air hose 14b. The air cylinder 14 includes both cylinder support shafts 12,
Both the cylinder support shafts 12 and 13 serving as pressing points by pressing the hand main body 2 in the direction away from the robot mounting portion 3 (downward in FIGS. 1 and 2) via 13
Is constantly urged to maximize the distance between them, and by supplying relatively low pressure air to the air cylinder 14 during the copying operation, the hand body 2 is elastically urged to a state capable of the copying operation, Further, during non-copying operation, the air cylinder 1
4 by increasing the pressure of the air supplied to the hand body 2
The rotation in the copying motion direction of is regulated.

Next, in the case where the robot hand 11 of the present embodiment configured as described above is attached to the tip of the arm and grips and conveys the work W selected from the work group randomly stacked in the pallet. Will be described with reference to FIG.

This robot captures the state of a large number of works stacked in a pallet from above with a TV camera and processes the images to obtain each data of the position and orientation of the work W that can be taken out by the robot hand 11. First, the work W is moved upward based on the position data in a state in which relatively low pressure air is supplied to the air cylinder 14 to enable the hand body 2 to rotate in the copying movement direction. After that, it also descends toward the work W based on the position data (see FIG. 3 (A)).

When one of the copying guides 6 of the descending robot hand 11 comes into contact with the high side of the inclined work W, the robot hand 11 further descends, and the lower connecting pin 7 and the upper connecting pin 8 cause the link 4 to move. The hand main body 2 connected to the robot mounting portion 3 via the rotary pin is bent with the connecting pins 12 and 13 as a fulcrum and is allowed to move in the vertical direction by the guide hole 4a. The guide 6 tilts in the direction approaching the lower side of the work W (see FIG. 3 (B)). At this time, when the hand body 2 tilts, the distance between the cylinder support shafts 12 and 13, which are the pressing points of the air cylinder 14, is shortened.
The elastic force that tends to separate the 13 from each other increases, and unnecessary swinging of the hand body 2 is prevented, and one of the copying guides 6 already in contact with the work W is appropriately elastically pressed to the work W. To abut on the base plate, so that an accurate copying operation is performed.

Then, when the hand body 2 further tilts and the other copying guide 6 comes into contact with the lower side of the work W, the hand body correctly follows the tilted posture of the work W, and both sensors of the copying guides 6 and 6 are detected. 6a, 6a both detect the contact of the two copying guides 6, 6 with the work W, actuate the claw opening / closing cylinder 9 to drive both gripping claws 5, 5 in the closing direction, and move the work W in the longitudinal direction. Hold it so that it is sandwiched from both ends (see FIG. 3 (C)). During such a copying operation, the hand body 2 tilts only within the plane of the connecting pins 7 and 8 along the radial direction, so that the copying operation is performed along the posture of the work W, and thus the work W is gripped. It can be done quickly and reliably.

When the hand body 2 grips the work W, the robot hand 1
1 starts rising. In the ascending process, the hand body 2 gripping the work W is elastically biased by the air cylinder 14 in the direction in which the lower connecting pin 7 and the upper connecting pin 8 are separated from each other. A state in which the distance between the cylinder support shafts 12 and 13 is maximum from the inclined state, that is, the connecting pins 7 and 8
Also, by arranging the cylinder support shafts 12 and 13 on the same vertical line, the hand body 2 is forcibly returned to a horizontal state (see FIG. 3 (D)).

Then, when the hand body 2 holding the work W becomes horizontal and rises to a certain height, the air supplied to the air cylinder 14 is switched to a high pressure, so that the maximum distance between the cylinder support shafts 12 and 13 is maintained. The movement of the hand body 2 in the copying operation direction is locked by restricting the reduction of the distance of the hand body 2 to prevent the hand body 2 from swinging during conveyance, and then the robot hand 11 that has risen to a predetermined height is horizontal. And moves the gripped work W to a predetermined position on an engine manufacturing line or the like.

As described above, in the present embodiment, the hand body 2 that makes the air pressure supplied to the air cylinder follow the posture of the work W.
By supplying a relatively low pressure air during the copying operation, the hand main body 2 is allowed to rotate in the copying operation direction and unnecessary swinging is prevented, so that the copying guide is surely brought into contact with the work W. An accurate copying operation can be performed, and during the non-copying operation of the hand body 2 that grips the work W and conveys the work W in the horizontal and vertical directions, the work W is gripped by increasing the supplied air pressure. It is possible to prevent shaking of the hand body 2.

FIG. 4 shows a robot hand according to a second embodiment of the present invention. In the robot hand 11 according to the first embodiment, the air pressure supplied to the air cylinder 14 provided on one side surface is supplied to the hand body 2. The robot hand 21 of the second embodiment is switched to the relatively low pressure that allows the copying operation of the robot body 2 and enhances the copying property and the high pressure that locks the rotation of the hand body 2 in the copying movement direction. In this case, the air having a constant pressure is intermittently supplied to the air cylinder 14 through the air hose 14b, and the coil spring 22 is wound around the outer periphery of the cylinder rod 14a of the air cylinder 14 to make the hand body 2 Of the cylinder supporting shafts 12 and 13 is always elastic in a direction in which the cylinder supporting shafts 12 and 13 are separated from each other by an elastic force that allows the copying operation of It is obtained by-energized.

At the time of the copying operation of the hand body 2, the air supply to the air cylinder 14 is cut off and the coil body 22 is urged only by the elastic force of the coil spring 22 to perform the copying operation of the hand body 2 with respect to the work W and to perform unnecessary swing. In addition, the air cylinder 14 prevents the hand body 2 from operating during non-copying operation.
By supplying air pressure to the coil spring 2
In addition to the elastic urging force of 2, the air cylinder 14 urges the cylinder supporting shafts 12 and 13 in a direction in which they are separated from each other, thereby increasing the urging force to lock the rotation of the hand body 2 in the copying operation direction. It is supposed to do.

Therefore, the robot hand 21 of the present embodiment does not need to be provided with an air switching circuit for switching the air pressure supplied to the air cylinder 14 unlike the robot hand of the first embodiment, and the robot hand of the first embodiment is not required. The same effect as the hand can be obtained.

Although the strength of the elastic urging force is switched in each of the above-described embodiments, the work may be conveyed even if the elastic urging force of the hand body is constantly urged with a constant elastic urging force. It is also possible to obtain the effect of preventing the shaking of the hand body at the time.

Further, in both the embodiments, the robot hand for mechanically gripping the work has been described, but the robot hand by other means such as gripping the work by negative pressure suction or holding the work by magnetic attraction. Can also be applied.

As described above, in the robot hand of the present invention, the hand body and the robot mounting portion are pin-connected to the hand body and the robot mounting portion, respectively, and the copying operation of the hand body is performed at each pin connecting portion. An actuator for connecting the hand body via a connecting member that allows the hand body to move in the direction of the robot mounting portion and elastically biases the hand body in a direction away from the robot mounting portion. An elastic urging means such as a spring is used as a pressing point between a position on the hand main body and a position on the robot mounting part on the straight line connecting the pin connecting parts and outside each of the pin connecting parts. Is provided so as to support the rotation of the pin connecting portions, and the pins of the pins are parallel to each other. Since it is arranged in the above position, the copying performance of the hand main body during the copying operation is improved, and the work gripping operation is not redone due to the defective copying of the hand main body, and the work cycle time can be shortened. Further, since the shaking of the hand body during the non-copying operation such as the conveyance of the work is prevented, the durability of each movable part of the robot hand is improved and the disconnection of the wiring can be prevented. Further, the hand body in the non-copying operation in which the urging force by the elastic urging means is strengthened is in a so-called regular posture in which the pin connecting portion and the pressing point are aligned, which is to simply increase the urging force. Therefore, it is easy to determine the posture of the work, and it is possible to simplify the setting and handling of the posture of the work after conveyance.

[Brief description of drawings]

FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a perspective view showing a robot hand, FIG. 2 is a partial sectional side view of the same, and FIGS. B), (C), and (D) are explanatory views showing the work holding process of the robot hand, respectively, FIG. 4 is a partial cross-sectional side view showing the robot hand of the second embodiment, and FIG. 5 is a conventional robot hand. FIG. 2 ... Hand body, 3 ... Robot mount, 4 ... Link, 4
a ... Guide hole, 4b ... Pin hole, 5 ... Gripping claw, 6 ... Copying guide, 7 ... Lower connecting pin, 8 ... Upper connecting pin 11, 12,
1 ... Robot hand, 12, 13 ... Cylinder support shaft, 1
4 ... Air cylinder, 14a ... Cylinder rod, 22 ... Coil spring, W ... Work.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takayuki Yamamoto 5-16 Hosoya-cho, Toyota-shi, Aichi Kito Kogyo Co., Ltd. (56) References JP-A-58-51091 (JP, A) JP-A-47 -44767 (JP, A) JP-A-59-59389 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A robot hand in which a hand main body for holding a work and a robot mounting portion for attaching to a robot arm of the hand main body are connected to each other so as to follow the work posture of the hand main body. A connecting member that connects the main body and the robot mounting portion is rotatably connected to each of the hand main body and the robot mounting portion by pins that are inserted with their axes parallel to each other, and one pin connecting portion is An actuator or a spring which is configured to be movable in a straight line connecting the pins and which elastically urges the hand body in a direction away from the robot mounting portion and which can change the urging force at least in two ways. The elastic urging means on the hand main body on the straight line connecting the both pin connecting parts and outside each of the pin connecting parts. Position and the position on the robot mounting portion between the respective two pressure point as the pressing point, the robot hand, characterized in that provided in the support to permit rotation of the respective pin connecting portions.