JPH03178794A - Robot hand for holding circular body - Google Patents

Abstract

PURPOSE:To hold a circular body having a comparatively large diameter with a uniform gripping power by providing one actuator which actuates a rotating work plate with its rotation and makes plural linking elements performing a holding motion or release motion at the same time at a foundation part. CONSTITUTION:A cylinder lever 52 in the cylinder 50 making the actuator of a finger operation part 18 is actuated first. Accordingly a circular working plate 60 is slided with its rotation and three links 58 are displaced with their movement to a broken line position from a continuous line position simultaneously. With this displacement of three links 58, the movable finger element 42 of a gripping finger 16 is slided in the center direction or concentric direction of the base plate 20 of a hand foundation part 12 simultaneously along guides 40a, 40b. According to this sliding of the movable finger element 42, a hook claw 44 provided at the outer end of the finger element 42 performs a close motion of a circular holding body W in the gripping direction, performing a gripping action firmly by acting a holding power in the inner direction from three directions at three positions in equal intervals of the outer periphery of the work W.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a robot hand that controls the end effector of an industrial robot, and in particular, the present invention relates to a robot hand that is attached to the wrist of an articulated industrial robot and is mainly used for automobile tires. Donut-shaped articles and disc-shaped articles (collectively referred to as circular articles) including
The present invention relates to a robot hand for grasping a circular object, which grips and conveys a circular object in a centripetal direction with a plurality of fingers, and performs a robot operation such as attaching the circular object to an object.

[Prior art]

Various types of robot nodes that have a structure for gripping cylindrical bars have already been provided. For example, a robot hand for attaching and detaching a round bar workpiece to and from a chuck device of a machine tool has already been provided by the present application (for example, there is U.S. Pat. No. 4,565,400). However, a round bar work or a relatively small diameter cylindrical bar can be reliably gripped by providing two finger elements and gripping the work in the diametrical direction with the two finger elements.

On the other hand, when grasping an object with a relatively large diameter and no length such as a bar, such as an automobile tire, when grasping the circular outer periphery with the fingers of the hand, it is difficult to hold a bar with a small diameter. The operating system of a robot node that grips objects cannot be applied as is, and when hand gripping force is applied from multiple positions around the circular periphery, there is a risk that the gripped object may fall off the robot node due to unbalanced forces. There is a problem with this.

[Problem to be solved by the invention]

However, the method using the dedicated tire gripping and conveying means described above is not versatile and can only be used on a specific vehicle assembly line, and therefore has the problem of being relatively expensive.

Furthermore, in the process of attaching tires to axles on automatic car assembly lines, etc., the process of attaching a tire to an axle becomes more complicated than expected due to the angle of inclination of the surface, which is unique to each vehicle. There was a problem.

Therefore, if the robot's hand could grip the wheels reliably and easily, even when the diameters of the wheels are different, by adjusting the amount of action of the gripping fingers according to the diameter of each wheel, it would be possible to use a general-purpose industrial robot. In particular, since general-purpose articulated industrial axis robots such as 6-axis robots have high motion capabilities in three-dimensional space, wheel grippers that can utilize this high motion capability to attach wheels to axles with high precision are developed. Provision of a portable robot hand is requested.

Furthermore, by using a general-purpose articulated robot, there is a need to reduce the high cost of assembly lines associated with the use of specialized machines.

Therefore, the main object of the present invention is to provide a robot hand that can grasp a tire-equipped wheel, transport it, and attach it to an axle, which meets the above-mentioned requirements.

Furthermore, another object of the present invention is to provide a robot hand for grasping circular objects that can be widely used for grasping circular objects of the same type as wheels, not just a robot hand for grasping wheels on a car assembly line. It is something.

[Solution]

In view of the above-mentioned object of the invention, the present invention applies a gripping force directed from multiple positions on the outer periphery of a circular object toward the center by operating a single gripping operation activation actuator to generate a plurality of gripping fingers that operate synchronously. To provide a robot hand which can be attached to the wrist of a general-purpose multi-jointed industrial robot and can carry out operations such as adjusting and attaching a circular object to an object to be attached, etc. under the control of a robot control device. It is something.

That is, according to the present invention, a hand base portion having a joint portion with a wrist of an industrial robot, a plurality of gripping fingers attached to the hand base portion for gripping and releasing a circular object; In the robot hand for grasping a circular object, the robot hand has a finger actuating section that operates the plurality of grasping fingers, each of the plurality of grasping fingers includes a guide fixed to the hand base, and a guide inside the guide that is connected to the hand base. The finger actuator is configured to have a movable finger element that performs a gripping operation and a releasing operation of a circular object by sliding toward the center of the hand and in the opposite direction thereof, and the finger operating section is rotatably provided with respect to the hand base. a plurality of coupling link elements having one end pivotally connected to the rotary actuating plate and the other end pivotally connected to each movable finger element of the plurality of grasping fingers; The present invention provides a robot hand for gripping a circular object, which includes one actuator that simultaneously grips or releases the plurality of link elements by rotationally starting an actuating plate.

[Effect]

According to the above configuration, the actuator of the finger actuation section causes the plurality of grasping fingers to synchronously slide along the guide in the centripetal direction to perform a grasping operation, and also slide in the opposite direction to perform a releasing operation. Moreover, since the hand base has a connection part to the robot's wrist, it can perform tasks such as grasping, transporting, and attaching circular objects with high precision according to the motion of the articulated robot. . Hereinafter, the present invention will be described in further detail based on embodiments shown in the accompanying drawings.

〔Example〕

FIG. 1A is a plan view of an embodiment of the robot hand for grasping a circular object according to the present invention, and FIG. 1B is a view showing the state in which the air cylinder forming the actuator of the robot hand is attached to the base of the hand. Side view, 2nd figure is 1st
A cross-sectional view taken along the line ■-■ in the figure, and FIG. 3 is a partial cross-sectional view showing the grasped object detection device.

Now, the robot hand according to the present invention is configured to be connectable to the wrist of a general-purpose industrial robot, and is particularly suitable for use in automatic car assembly lines.
By connecting it to the wrist of an industrial robot, it can be used in the process of assembling a wheel to the hub surface of an axle.

Referring to FIGS. 1A, 1B, and 2, a robot hand 10 according to an embodiment of the present invention has a structure that is coupled to a wrist 8 (FIG. 2) of an articulated industrial robot. The basic structural elements include a hand base 12 made of a polygonal plate member, a wrist coupling tool 14 provided on the hand base 12, and a plurality of positions, preferably three positions, on the hand base 12. The gripping finger 16 is provided, and a finger operating section 18 that operates the plurality of flashing fingers 16 at the same time is provided, and a circular object, such as a wheel, is used as the workpiece W to be gripped.

The coupling tool 14 provided on the hand base part 12 is formed with a bracket 30 attached to the base plate 20 of the hand base part 12 with bolts and screws, and a positioning plate 32 provided on the outer end of this bracket 30. A positioning protrusion 34 is formed on the positioning plate 32, and this protrusion 34 fits into a recess formed in the surface for attaching the wrist 8, so that the robot hand 10 is always attached to the wrist 8 in a constant posture. is what you get.

The base plate 20 of the hand foundation part 12 is made of a polygonal plate with a relatively large-diameter working opening 22 formed in the center, and the working opening 22 is used for attaching, for example, a wheel workpiece W to the hub surface of an axle (not shown). This hole is provided as a tool insertion hole to allow a torque wrench tool, etc. for bolting the axle and wheel to access the working part.If it is not needed, it may be removed or formed into a small diameter hole. .This working opening 22
There is a ring-shaped fixed pedestal 24 around the fixed pedestal 2.
4, and a circular raceway plate 26 provided at an appropriate height distance from the base plate 20, and the fixed pedestal 24 and the circular raceway plate 26 are connected by bolts and screws 28.
It is fixed to the base plate 20. The circular track plate 26 has an outer circumferential surface 26a having a circular track, as will be described later.

Further, the flashing fingers 16 provided at three locations on the base plate 20 of the hand base portion 12 are arranged concentrically with the center of the opening of the base plate 20 at equal intervals, and each grasping finger 16 A pair of left and right guides 40a, 40b mounted on one surface, that is, a surface opposite to the surface facing the workpiece W, and a movable member slidably fitted between the pair of left and right guides 40a, 40b. It has a finger element 42 and a claw element 44 provided so as to protrude outward from the outer end of the movable finger element 42. The pair of left and right guides 40a and 4Qb are formed of well-known cross roller type guide members, thereby making the sliding motion of the movable finger element 42 smooth and reliable, and further improving the workpiece flash of the same element 42. It is possible to improve the accuracy of the action. As shown in the figure, the movable finger is a sliding member having a substantially rectangular outer shape, and slides between a pair of guides 40a and 40b on both sides to direct the hand base 12 toward the center of the base plate 20 and its direction. When moving in the opposite direction, the three gripping fingers 16 cooperate to perform a gripping action on the workpiece when moving toward the center, and when moving outward,
It is hollowed to release the gripped workpiece W. The above-described claw element 44 is attached to the movable finger element 42 with bolts and screws as shown in the figure, and in this embodiment,
The base plate 20 is bent in an L-shape from one side to the other side facing the workpiece W, creating a hook-shaped shape. Then, in response to the gripping and releasing operations of the movable finger elements 42, the hook-shaped wind 44 engages with the gripping workpiece W such as a tire of a wheel, as shown in FIG. 2, and performs a gripping action ( (shown in broken lines in FIG. 2), and is also retracted to a release position (shown in solid lines in FIG. 2) to release the workpiece.

One end of a rod-shaped link 58 is pivotally attached to the center position of each movable finger element 42 of the three flashing fingers 16 via a pin member 59. This link 58 is connected to the finger operating section 1 described above.
8, and the other end of the link 58 is connected to the finger operating section 1.
Similarly, it is pivotally connected to a rotary actuating plate 60, which constitutes another element of 8, via a pin member 50. The rotary operating plate 60 is a ring-shaped member provided to rotate and slide along the circular raceway surface 26a of the circular raceway plate 26 of the hand base portion 12. The front end side of the joint 54 is pivotally attached via a pivot pin 56, and the rear end side of the pivot joint 54 is engaged with a screw or the like at the tip of the reciprocating cylinder rod 52 of the cylinder 50 that controls the actuator. They are combined using an appropriate binding method. A single cylinder 50 is mounted on the base plate 20 of the hand foundation 12, and the rear end side of the cylinder 50, that is, the end opposite to the end where the cylinder rod 52 enters and exits, is also connected via a joint member 57. Pivotably mounted. In other words, the finger operating section 18 is formed using the cylinder 50 having the cylinder rod 52, the rotary operating plate 60, and the link 58 as basic elements. When the cylinder rod 52 of the cylinder 50 moves along a straight reciprocating path in the protruding and retracting directions, the finger operating plate 60 rotates and slides in both directions via the pivot joint 54. At this time, the gripping operation and the release operation of the gripping fingers 16 are orbited in accordance with the displacement operation of the link 58 pivotally connected to the rotary operation plate 60.

As shown in FIG. 1A and FIG. W
A gripping workpiece detector 70 is attached to detect the gripped workpiece.

This grasped workpiece detector 70 detects the workpiece W on the base plate 20.
It has a movable detector 72 that is biased by a spring 74 in the direction of the workpiece W from the surface facing the workpiece W, and its tip is located at the detection end 7 of the workpiece W.
2a, and the other end is an operating end 7 that activates a detection signal device 76.
It is intimidating 2b. The detection signal device 76 is a detector 76a that emits a signal when the detection end 72a of the detector 72 engages with and detects the gripped workpiece W, and detects the gripped workpiece W even though the workpiece gripping action of the robot hand 10 is activated. and a detector 76b which emits a detection signal to detect a failure in gripping the workpiece W when the workpiece W is not gripped, and each detector 76a and 76b is formed by a known switching means such as a proximity switch or a limit switch. All the signals from the detection signal device 76 consisting of these detectors 76a and 76b are
The signal is fed back to a robot control device (not shown) and is used as a signal to control the robot's gripping and releasing actions on a circular object.

Now, the operation of the robot hand 10 of this embodiment will be explained with reference to FIGS. 1A and 2.

When the robot hand 10 grasps a circular object, such as a wheel with tires W, first, the cylinder rod 52 of the cylinder 50 that controls the actuator of the finger actuator 18 is pressed.
is activated. The activation of this cylinder 50 is performed by a robot,
This occurs in response to a gripping command signal from a control device (not shown). When the cylinder rod 52 of the cylinder 50 operates,
The rotary operation plate 60 of the finger operation section 18 rotates and slides along the circular raceway surface 26a of the circular raceway plate 26. At this time,
Needless to say, the circular raceway plate 26 rotates and slides, and the sliding direction is set in advance to correspond to the gripping operation direction and the release operation direction. When the circular actuating plate 60 rotates and slides, since the three links 58 are all pivotally connected to the same circular actuating plate 60, the three links move simultaneously from the solid line position to the broken line position in FIG. 1A. The displacement of these three links 58 causes the movable finger element 42 of the grasping finger 16 to move towards the guides 40a, 40.
b, the hand base portion 12 slides all at once toward the center or centripetally on the base plate 20.

According to this sliding of the movable finger element 42, the claw 44 provided at the outer end of the finger element 42 moves to close the circular gripped object (workpiece) W in a flashing direction. The gripping force is applied inward from three directions at the position to firmly grasp the object. In this way, after gripping the circular gripped object W, the robot moves the object to be transported,
For example, operations such as adjustment, attachment, and detachment of the circular gripping object W to the hub surface of the axle are performed. At this time, the robot hand 10 can be freely displaced in three-dimensional space by making full use of the motions around the robot's multiple joints via the robot wrist 8 (Fig. 2). Various adjustment operations can be performed, such as aligning and installing the device at an angle of inclination. When releasing the gripped circular gripped object W, the cylinder rod 5 of the cylinder 50 of the finger actuation section 18
It is easy to understand that if the gripping fingers 2 are operated in the opposite direction, the plurality of gripping fingers 16 will perform the releasing operation all at once.

The present invention has been described above according to the embodiments, but the lower claws 44 of the grasping fingers 16 of the embodiments are
It goes without saying that the shape of the claws etc. may be designed and changed as appropriate depending on the condition of the outer peripheral surface of each circular workpiece. Furthermore, although a commercially available air cylinder can be used as the cylinder 50, a hydraulic cylinder or the like may also be used depending on the gripping force. Furthermore, it goes without saying that the shape of the base plate 20 of the hand base portion 12 should be arbitrarily selected according to the manner of work to be performed on the object to be grasped. Also, the number of fingers is not limited to 3, but may be 4 fingers or 4 fingers as needed.
Needless to say, five fingers can also be operated all at once in response to the rotational and sliding movement of the rotary actuating plate.

〔Effect of the invention〕

According to the present invention, there is provided a robot hand capable of gripping a circular object having a relatively large diameter, and gripping force is uniformly applied from a plurality of positions on the outer periphery of the circular object, particularly from three positions. Since the gripping force can be used to perform the gripping operation, transporting circular objects, attaching objects to objects, etc. can be carried out with high precision by utilizing the multi-functions of the articulated general-purpose robot.

In particular, it is a highly reliable robot that can be used on an automatic car assembly line to reliably grip wheels with tires and attach the wheels to the axle precisely and automatically according to a program using robot work. Actuated tire mounting can be provided. At this time, it is also possible for other robots to perform other types of work such as bolt tightening using the central opening of the base plate of the hand foundation, making it possible to use a general-purpose robot, so assembly line The advantage is that the cost can also be reduced. Further, since the finger actuating section 18 is structured to actuate a plurality of fingers at the same time using only a single cylinder, it is possible to provide a lightweight, highly accurate, and inexpensive robot hand.

[Brief explanation of drawings]

FIG. 1A is a plan view of an embodiment of a robot hand for grasping a circular object according to the present invention; Figure B is a side view taken in the direction of arrows showing how the air cylinder forming the actuator of the robot hand is attached to the hand base, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is FIG. 3 is a partial cross-sectional view showing a grasped object detection device. 10... Robot hand, 12... Hand basic part,
DESCRIPTION OF SYMBOLS 14... Connector, 16... Flashing finger, 18... Finger actuating part, 20... Base plate, 40a, 40b... Guide, 42... Movable finger element, 44... Nails, 50...
Cylinder, 52... Cylinder rod, 58... Link,
60...Rotary operation plate, 70...Gripped workpiece detector.

Claims (1)

[Scope of Claims] 1. A hand base portion having a connecting portion to the wrist of an industrial robot; a plurality of grasping fingers attached to the hand base portion for gripping and releasing a circular object; In a robot hand for grasping a circular object, the robot hand has a finger actuation section that operates a plurality of grasping fingers, each of the plurality of grasping fingers includes a guide fixed to the hand base, and a guide inside the guide that is connected to the hand base. movable finger elements that perform gripping and release operations on circular objects by sliding in the direction of the center of the hand and in the opposite direction; the finger operating part is rotatable with respect to the hand base; a rotatable actuating plate provided; a plurality of coupling link elements having one end pivotally connected to the rotatable actuating plate and the other end pivotally connected to each movable finger element of the plurality of grasping fingers; 1. A robot hand for grasping a circular object, comprising: one actuator that simultaneously causes the plurality of link elements to perform a grasping operation or a release operation by rotationally starting a rotary actuating plate. 2. The plurality of grasping fingers are provided three at equal intervals on a substantially concentric circle with respect to the center of the hand base, and the tip of each movable finger element is formed with a substantially L-shaped hook-shaped claw. The robot hand for grasping a circular object according to claim 1, characterized in that: 3. The robot hand for grasping a circular object according to claim 2, wherein each of the movable finger elements comprises a rectangular plate member. 4. The hand base portion is made of a disc member having an opening in the center, and the rotary operating plate formed in an annular shape is rotatable around a circular fixed track element fixed around the opening of the disc member. The robot hand for grasping a circular object according to claim 1, wherein the robot hand is attached to a robot hand for grasping a circular object. 5. The gripped object detection means is fixed to the hand base and detects the circular object in response to the gripping and releasing operations of the plurality of gripping fingers. The robot hand for grasping a circular object according to claim 1.