JPH05154785A - Automatic tool exchanger - Google Patents

Abstract

PURPOSE:To assure the action of a lock pin when a tool plate is fitted or separated and maintain the quick work of a robot hand by reciprocating the lock pin of a fixed plate with a link system. CONSTITUTION:When a moving piece is moved, joint sections of the first and second moved connecting rods 7, 8 connected to it are moved in the same direction as the moving direction of the moving piece. The reciprocating direction of a lock pin 5 is nearly perpendicular to the moving direction of the moving piece, the first and second moved connecting rods 7, 8 are aligned on a straight line to advance the lock pin 5, they are folded into a V-shape to retreat it, thus the lock pin 5 can be reciprocated. The action of the lock pin 5 is surely maintained by a link system, and a tool plate 2 is quickly locked or unlocked to the fixed plate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tool changer which can be used for industrial robot hands or the like to automatically change tools.

[0002]

2. Description of the Related Art An arm of an industrial robot is equipped with an automatic tool changer for changing a tool for machining. This automatic tool changer is capable of aligning and connecting a tool plate in which a tool is integrated with a fixed plate connected to an arm of a robot.
As such an automatic tool changer, for example, there is one proposed by the present applicant and published as Japanese Utility Model Publication No. 3-43174.

This is to provide a plurality of lock pins in a direction orthogonal to a coupling axis with a fixed plate to be mounted inside a fixed plate attached to the tip of an arm of an industrial robot hand. It is configured such that the cylinder is driven to retract from the peripheral surface of the fixed plate. In this case, after inserting the fixed plate into the mounting portion of the tool plate, the lock pin is driven so as to protrude, and the lock plate is engaged by engaging with the lock hole provided in the tool plate.

As a mechanism for moving the lock pin, as described in the above publication, the taper joint with the peripheral surface of the actuator of the cylinder is used to move the lock pin in the protruding direction, and when the lock pin is retracted, the restoring force of the spring is used. Can be used. Further, instead of this structure, the actuator and the lock pin may be connected by a link, and the lock pin may be projected and retracted in association with the advance and retreat of the actuator.

[0005]

However, in the case where the lock pin is disengaged from the lock hole of the fixing plate by utilizing the restoring force of the spring, rusting of the spring and foreign matter on the portion housing the spring are prevented. By intrusion
There is a high risk of malfunction. Further, the metal fatigue of the spring attenuates the restoring force, which affects the quick movement of the lock pin.

From this point of view, in the case where the actuator is linked with the link, the lock pin is forcibly moved by the movement of the actuator, so that the operation is highly reliable.

However, it is necessary to lengthen the stroke of the actuator as compared with the taper joint type. That is, in taper joining, the stroke of the lock pin increases as the inclination angle of the taper increases, so that the stroke of the lock pin can be obtained by increasing the outer diameter of the actuator. Therefore, the fixed plate does not have a large axial length. On the other hand, when the link is used, the movement amount of the actuator which is almost equal to the stroke of the lock pin is required. For this reason, even if the outer diameter of the actuator is small, the bulkiness of the fixed plate in the axial direction is increased in order to increase the stroke thereof.

In the automatic tool changer, various tools are attached / detached and the work is processed. Therefore, it is an important design item to be small and lightweight. Therefore, although it is better to connect the link to the actuator for the operation of the lock pin, if the fixed plate becomes longer in the axial direction due to the expansion of the stroke of the actuator, the axis of the load center of gravity acting on the robot from the drive source of the robot arm Since the distance in the direction increases, a new obstacle to the function, that is, the load capacity of the robot, is reduced.

The problem to be solved in the present invention is to provide an automatic tool changer in which the operation of the lock pin is ensured by the link mechanism and the bulk of the fixing plate can be kept small.

[0010]

According to the present invention, a fixing plate connected to an arm or the like of a robot hand and a tool plate provided with a tool can be attached and detached in a direction orthogonal to the attaching and detaching direction with respect to the tool plate. An automatic tool changer having a lock plate for advancing and retracting in a fixed plate, and a lock hole into which the lock pin is fitted in the tool plate, wherein the fixing plate has a direction substantially orthogonal to a forward and backward direction of the lock pin. A movable element is provided on the fixed plate, a first driven connecting rod is connected to the fixed plate so as to be swingable in the moving direction of the movable element, and the base end of the lock pin is shaken in the moving direction of the movable element. Movably connecting a second driven connecting rod, and further connecting a drive system of the mover to a joint connecting the first and second driven connecting rods. The features.

[0011]

When the moving element moves, the joint parts of the first and second driven connecting rods connected to the moving element move in the same direction as the moving direction of the moving element. Since the forward / backward direction of the lock pin is substantially orthogonal to the moving direction of the mover, the first and second driven connecting rods are arranged in a straight line when the lock pin is advanced, and V is set when the lock pin is retracted.
If it is folded in a letter shape, the lock pin can be moved back and forth. Therefore, the link mechanism maintains the reliability of the operation of the lock pin, and the tool plate is locked and unlocked with respect to the fixed plate promptly.

In comparison with the structure in which one connecting rod is used for connecting the moving element and the lock pin,
Even if the first and second driven connecting rods are half the length of this one connecting rod, the maximum stroke of the lock pin is obtained when the two driven connecting rods are arranged in a straight line. ,
Same as using one connecting rod.
Then, regarding the stroke of the moving element, since the common joint of the two driven connecting rods is moved,
It's half as much as using a connecting rod in a book. Therefore, even if the lock pin is moved by the link mechanism, it is not necessary to increase the stroke of the moving element, and the bulk of the fixing plate can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded vertical sectional view showing a fixed plate of an automatic tool changer of the present invention together with a tool plate, FIG. 2 is a vertical sectional view when the fixed plate is inserted into the tool plate, and FIG. It is a longitudinal cross-sectional view when the tool plate is locked.

In the figure, the automatic tool changer comprises a fixed plate 1 which is attached to an industrial robot hand (not shown), in which members such as lock pins are housed. The tool plate 2 mounted on the fixed plate 1 is used by mounting various tools (not shown) on the front surface. The tool plate 2 is provided with a hollow portion 2a having a circular cross section so that the tip portion of the fixed plate 1 can be inserted therein, and lock holes 2c are provided at a plurality of positions on the peripheral wall 2b around the hollow portion 2a.

The fixing plate 1 is provided with a cylinder bore 1a having a circular cross section in the center thereof in the axial direction, and a lock air supply passage 1b and an unlock air supply passage 1c (see FIG. 3) are made to communicate with the cylinder bore 1a, respectively. The supply paths 1b and 1c are connected to an external air supply source (not shown).

The inside of the cylinder bore 1a is formed as a closed space, and the rod 3 is coaxially fixed therein. Around the rod 3, a piston 4 that slides on the inner peripheral wall of the cylinder bore 1a is slidably connected. The piston 4 moves upward when air is press-fitted from the lock air supply passage 1b in FIG. 3, and moves downward when air is sent from the unlock air supply passage 1c. A spring 4a is built around the piston 4, and the spring 4a biases the piston 4 from the mounting surface side of the tool plate 2 toward the robot hand side.

The fixed plate 1 is provided with a plurality of slide holes 1d penetrating from the cylinder bore 1a to the outer peripheral surface, and the lock pin 5 is slidably incorporated in the slide holes 1d. The number and positions of the lock pins 5 are the same as those of the lock holes 2c of the tool plate 2, and a packing 5a for sealing is attached to each of them on the peripheral surface. Each of these lock pins 5 corresponds to the movement of the piston 4 in FIG.
It is movable as shown in FIG. 3, and for this driving, each lock pin 5 and piston 4 are connected by a link mechanism.

This link mechanism is composed of a drive connecting rod 6 having one end pivotally attached to the piston 4 and first and second driven connecting rods 7 and 8 connected to the lower end thereof. One end of the first driven connecting rod 7 is pivotally attached to the block 1e that constitutes the sealing wall of the cylinder bore 1a, and the other end is connected to the tip of the drive connecting rod 6 via a pin 9. The second driven connecting rod 8 has one end pivotally attached to the base end of the lock pin 5 and the other end connected to the drive connecting rod 6 through a common pin 9. Therefore, the drive connecting rod 6 connects the two first and second driven connecting rods 7 and 8 with the pin 9. When the lock pin 5 is retracted as shown in FIG. 1, the position of the pin 9 is biased toward the mounting surface side of the tool plate 2 with respect to the axis of the lock pin 5 as shown in the drawing, and the first and second driven connecting members are connected. The rods 7 and 8 have a V-shaped crossing posture.

In the above structure, the process of connecting the tool plate 2 to the fixed plate 1 so that the tool mounted on the tool plate 2 can be used by the robot hand is as follows.

First, in order to connect the tool plate 2 in which a new tool is mounted to the fixed plate 1, the piston 4 is unlocked and the lock pin 5 is set to the retracted position as shown in FIG. Then, for example, rough positioning is performed with respect to the tool plate 2 placed on a dedicated rack or the like,
As shown in FIG. 1, the fixed plate 1 is set so as to be substantially coaxial with the tool plate 2.

Next, by moving the robot hand, as shown in FIG.
As shown in, the fixed plate 1 is inserted into the cavity 2a of the tool plate 2 from the tip side thereof. At this time, it is needless to say that the lock pin 5 is operated while confirming the position of the lock hole 2c. Then, after confirming the position of the fixed plate 1 with respect to the tool plate 2 again, air is sent from the external air supply source through the lock air supply passage 1b. As a result, the pressure of the air flowing into the cylinder bore 1a causes the piston 4 to move away from the tool plate 2 as shown in FIG. The drive connecting rod 6 also moves upward in the figure in conjunction with the movement of the piston 4,
As a result, the first and second driven connecting rods 7, 8 connected at one end by the pin 9 gradually change their postures from the V-shaped posture to be substantially horizontal. By such movements of the first and second driven connecting rods 7 and 8, the lock pin 5 is pushed outward as shown in FIG. 3, and the tip end thereof is fitted into the lock hole 2c.

As described above, the tool plate 2 is locked to the fixed plate 1 via the lock pin 5 and integrally coupled, and in this state, the work using the tool provided on the tool plate 2 becomes possible. Even if the air supply pressure fluctuates, the piston 4 is urged by the spring 4a, so that even if the piston 4 is lowered in the figure, resistance is exerted and the locked state is maintained.

Further, from the fixed plate 1 to the tool plate 2
When the air is removed, air is supplied from the unlocking air supply passage 1c, and this flows in from the upper surface side of the piston 4 in FIG. Therefore, the piston 4 gradually descends due to the air supply pressure, and finally returns to the state of FIG. At this time, the horizontal first and second driven connecting rods 7 and 8 are folded in a V shape, and as a result, the lock pin 5 is retracted toward the center side and separated from the lock hole 2c. Then, if the fixed plate 1 is pulled out from the tool plate 2, the tool plate 2 can be separated from the fixed plate 1 as shown in FIG. 1, and another tool plate equipped with a new tool is mounted to process a workpiece. To continue.

Here, the lock pin 5 includes two first and second lock pins.
It operates with a stroke determined by the movement of the driven connecting rods 7, 8. Alternatively, a single moving connecting rod may allow an action equivalent to this stroke, but in this case the stroke of the piston 4 is increased. This will be described with reference to FIG.

In this figure, the connecting rod 10 corresponding to the second driven connecting rod 8 has a distance L (= 2P) which is twice the distance P between the respective pivot points of the first and second driven connecting rods 7, 8. ).
When the piston 4 is located at the lowest end in the figure, the angle formed by the line segment connecting the respective pivot points of the lock pin 5 and the drive connecting rod 6 to the axis of the lock pin 5 is θ.

When the connecting rod 10 changes its posture due to the ascent of the piston 4, the stroke for pushing out the lock pin 5 becomes maximum when the connecting rod 10 becomes horizontal as shown by the one-dot chain line in the figure. Therefore, the stroke of the piston 4 may be A in the figure, and if the pivot point of the piston 4 with the drive connecting rod 6 moves in the vertical direction in the figure, the movement of the lock pin 5 from the initial position at this time. The quantity B is B = (1-cos θ) · L.

Here, when the first and second driven connecting rods 7 and 8 having a half length of the connecting rod 10 are made substantially linear as shown in FIG. 3 and the lock pin 5 is moved to the maximum stroke, The first and second driven connecting rods 7 and 8 are 2 × (1-cos θ) ·
Since P = B, the same maximum stroke of the lock pin 5 can be obtained even if the lock pin 5 is divided into two pieces.

On the other hand, the stroke A of the piston 4 in FIG. 4 is A = L · sin θ. On the other hand, in the case of FIG. 1 and FIG. 2, since the distance between the pivot points of the first and second connecting rods 7 and 8 inclined in the V shape is L, these connecting rods 7 and 8 are The movement amount C when the posture becomes substantially horizontal can be approximated as C = P · sin θ. Therefore, the first and second driven connecting rods 7, 8 having a length half that of the connecting rod 9 are formed.
If the piston 4 is connected, the size of the stroke C of the piston 4 may be set, and from the relationship of L = 2P, half of the stroke A in the case of the connecting rod 10 will suffice.

As described above, when the same maximum stroke is given to the lock pin 5, as compared with the case where one connecting rod 10 is used, the connecting rod 10 is divided into two first rods having the same half length. , Second
When connecting the driven connecting rods 7 and 8,
The stroke of the piston 4 is half.

For the above reasons, the stroke of the piston 4 can be shortened in the same manner even when the first and second driven connecting rods 7 and 8 shown in the figure are connected to the piston 4. For this reason, when the maximum stroke of the lock pin 5 is set to the same value, the stroke of the piston 4 is reduced to about half as compared with the case of using the piston and one connecting rod as shown in the conventional example.
Therefore, the bulkiness of the fixed plate 1 in the axial direction does not increase, and the functional obstacle does not occur.

[0031]

As described above, according to the present invention, since the lock pin of the fixed plate is moved forward and backward by the link mechanism, the lock pin is reliably operated when the tool plate is attached or detached, and the robot is swiftly operated. The work of the hand is maintained. Further, by connecting the joints of the two driven connecting rods to the moving element, the stroke of the moving element can be reduced by half as compared with the case of using a single connecting rod. Therefore, even if the link mechanism is used, the bulkiness of the fixed platen in the axial direction can be suppressed and the weight does not increase, so that the tool can be optimally used as a tool changing device for a robot hand.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a fixed plate and a tool plate in an exploded manner.

FIG. 2 is a vertical cross-sectional view when the tip side of a fixed plate is inserted into a cavity of a tool plate.

FIG. 3 is a vertical cross-sectional view when the fixed plate and the tool plate are coupled and locked by a lock pin.

FIG. 4 is a schematic diagram for explaining a movement amount of a stroke of a lock pin by a single connecting rod.

[Explanation of symbols]

 1 Fixed Plate 2 Tool Plate 2c Lock Hole 3 Rod 4 Piston 5 Lock Pin 6 Drive Connecting Rod 7 First Driven Connecting Rod 8 Second Driven Connecting Rod 9 Pin

Claims (1)

[Claims] 1. A fixing plate connected to an arm of a robot hand and a tool plate provided with a tool are made detachable, and a lock pin for advancing and retracting in a direction orthogonal to the attachment / detachment direction to / from the tool plate is used as the fixing plate. An automatic tool changer having a lock hole into which the lock pin fits, wherein the fixed plate is provided with a movable element that is movable in a direction substantially orthogonal to the forward / backward direction of the lock pin. A first driven connecting rod is connected to the fixed plate so as to be swingable in the moving direction of the moving element, and a second driven connecting rod is swingably connected to the base end of the lock pin in the moving direction of the moving element. And a drive system of the mover is connected to a joint connecting the first and second driven connecting rods. apparatus.