JPH0613803Y2 - Tool gripping mechanism of automatic tool changer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improved tool gripping mechanism for a tool changing arm of a machining center or the like.

2. Description of the Related Art Conventionally, as a known technique for a tool gripping and locking mechanism in a tool changing arm of an automatic tool changing device (hereinafter referred to as ATC), there is JP-A-58-75647. This product is equipped with a roller shaft, which is always biased in the outer end direction by a spring in the exchange arm, to prevent the gripping tool from falling off at right angles to the turning axis direction, and a movable shaft with a cam surface is used for tool replacement. The tool is operated by fluid pressure prior to tool removal and after insertion to release the roller shaft from the locked state.

Problems to be Solved by the Invention In the technique of Japanese Utility Model Laid-Open No. 58-75647 described in the prior art, if the swivel speed of the tool change arm is increased in response to the recent need for shortening the ATC time, it is When the roller shaft and the tool come into contact with each other, a loud collision noise is generated,
There is a problem that impacts are transmitted to tools, ATCs, etc., which can cause adverse effects.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a tool gripping mechanism that does not generate a collision noise during gripping.

Means for Solving the Problems In order to achieve the above object, a tool gripping mechanism of an ATC according to the present invention is movable in a direction perpendicular to an arm rotation axis and is always biased in a direction for gripping a tool to grip the tool. In addition, in the automatic tool changer such as a machining center provided in the exchange arm, a roller shaft for preventing the tool from falling off is unlocked when the gripping tool is released, and is pivotally supported by a pin provided at a right angle to the roller shaft. And a cam follower that is provided in the main body of the exchanging device in parallel with the swivel surface of the exchanging arm and engages with the cam follower at the position where the exchanging arm swivels for gripping or releasing the tool from the standby position to immediately before gripping the tool. And an arcuate cam (20) for retracting the roller shaft, thereby eliminating the interference between the roller shaft and the tool when gripping the tool.

When the machining with the tool attached to the spindle is completed and the headstock moves in the Y-axis direction or the X-axis direction and is positioned at the tool exchange position, the standby exchange arm swivels for tool exchange. The exchange arm at this position has the roller shaft unlocked by the notch cam, and the roller shaft is in contact with the arc-shaped cam fixed to the ATC body from the standby position to immediately before the tool is gripped, and the spring force is increased. It is designed so that it will not be abutted against the tool by being pulled in against. Immediately before the tool gripping claw near the end of turning contacts the tool, the cam follower separates from the arcuate cam and the roller shaft is pushed out by the force of the spring to press the tool against the gripping claw and grip it. Then, when the replacement arm begins to move forward in the direction of the turning shaft for removing the tool, the roller shaft is separated from the notch cam, the inner end of the roller shaft contacts the outer circumference of the turning shaft, and the backward movement is restricted, so that the roller shaft is locked.

Examples Examples will be described with reference to the drawings.

1 to 4, the ATC main body 1 is rotatably supported by a bearing 2 and is rotated by a turning drive device (not shown) on a spline 3a formed in a center hole of a turning shaft 3 of an arm. The spline shaft 4 is meshed so as to be movable in the axial direction. An exchange arm sleeve 5 is pivotally supported on the outer periphery of the swivel shaft 3 so as to be movable in the axial direction, and the exchange arm 6 is fitted to the outer periphery of the sleeve 5 with a bolt. A connecting plate 9 is provided between the end surface of the disc 7 fixed to the left end surface of the sleeve 5 and the end surface of the exchange arm 6 via a thrust bearing 8. The connecting plate 9 is a piston rod of a hydraulic cylinder (not shown). The sleeve 5 is fixed to the tip of the cylinder 10, the sleeve 5 is moved in the axial direction by switching the pressure oil supplied to the cylinder, and the replacement arm 6 is in the standby position at the retracted end and the tool insertion completion position and the tool removal completed position at the advance end. And moved to.
Further, the right end surface of the sleeve 5 and the right end of the spline shaft 4 are connected via a flange 11, and the spline shaft 4 is axially moved together with the exchange arm 6.

The exchange arm 6 has semicircular tool gripping claws 6a at both ends, and a right-angled hole 6b penetrating the sleeve 5 is formed in the turning shaft 3 symmetrically with respect to the turning center. The shaft 14 is inserted so as to be movable in the axial direction. An abacus ball-shaped roller 12 is provided at the outer end of the roller shaft with its axis parallel to the gripping tool axis, and a roller 13 is provided at the inner end with its axis perpendicular to the turning axis. The roller shaft 14 is biased by a spring 15 toward the tool gripping claw, and a stopper 16 for preventing the roller shaft 14 from coming off is fixed to the side surface of the exchange arm 6. Further, the swivel shaft 3 is provided with a notch cam 3b at a position corresponding to the roller shaft of the exchange arm at the backward end position, and the roller shaft 1 is provided at the backward end position.
4 is an unlocked state in which it can be moved in the axial direction by the gap amount between the bottom surface 3b of the notch cam and the roller 13, and when the replacement arm starts to move forward via the connecting plate 9 by the hydraulic cylinder, the roller disengages from the notch cam. 13 is brought into contact with the outer circumference of the turning shaft 3 to restrict the backward movement, and the lock state is established.

Further, a pin 18 is planted on the roller shaft 14 at a right angle to the shaft center. The pin 18 penetrates the elongated hole 6c of the exchange arm and the tip projects toward the ATC body side. It is rotatably supported. On the other hand, an arcuate cam 20 is fixed to the end surface 1a of the ATC main body 1 symmetrically about the turning axis, and the cam follower and the arcuate cam are at the backward end position in the turning axis direction in which the replacement arm turns to grip or release the tool. And can be engaged with each other, and are separated by the forward movement of the exchange arm.At the retracted end position, the swing angle is neutral with respect to the spindle and the standby pot (not shown) from the standby position until just before gripping the tool. The cam follower 19 comes into contact with the cam surface 20a and pulls the roller shaft against the notch cam 3b against the force of the spring 15, and the cam follower 19 contacts the cam surface 20a immediately before the grip claw 6a comes into contact with the tool near the end of turning. And the roller shaft is released,
The force of the spring 15 presses the tool against the tool gripping claw 6a.

Next, the operation of the tool gripping mechanism of the present invention will be described. When cutting with the tool mounted on the spindle is completed and the headstock moves in the X-axis or Y-axis direction and is positioned at the tool replacement position, the NC tool replacement command causes the standby arm 6 to hold the tool. Turn. At this time, the cam follower 19 of the roller shaft 14 is drawn in contact with the arcuate cam 20, the outer end roller 12 passes through the tool without contacting the V groove 21a of the tool 21, and the tool gripping claw 6a is moved toward the tool. V groove 2
Immediately before coming into contact with the roller 1a, the cam follower gradually separates from the cam along the inclined surface of the end, and the roller 1 at the outer end of the roller shaft
2 is brought into contact with the V groove 21a of the tool 21 by the force of the spring, and the tool is pressed against the tool gripping claw 6a and gripped.

Subsequently, when the pressure oil supplied to the hydraulic cylinder (not shown) is switched and the exchange arm 6 holding the tool at both ends via the piston rod 10 and the connecting plate 9 advances, the roller shaft 14
Is separated from the notch cam and the roller 13 at the lower end abuts the outer circumference of the swivel shaft to restrict the backward movement of the roller shaft and lock the gripping tool to prevent the gripping tool from falling off. Removed from the pot. Next, the spline shaft 4 is rotated by a turning drive device (not shown), and the exchange arm 6 is turned 180 degrees through the turning shaft 3 and the sleeve 5.
° C Swiveling and gripping tools are exchanged, changing arm 6
Retracts and the gripping tool is inserted into the spindle and the standby pot,
The notch cam comes directly below and the roller shaft 14 is unlocked. When the exchange arm starts to turn in the opposite direction to the above-mentioned gripping of the tool, the cam follower comes into contact with the cam surface 20a, pulls in the roller shaft, and the exchange arm becomes empty and returns to the standby position.

Effects Since the present invention is configured as described above, it has the following effects.

The replacement arm pivots from the standby position, and the cam pulls the roller shaft inward against the spring force until just before the tool gripping claw at the tip comes into contact with the tool. No collision noise is generated, the swivel speed of the exchanging arm can be increased, and the tool exchanging time can be shortened.

[Brief description of drawings]

FIG. 1 is a side cutaway view of the present invention with a part omitted, FIG. 2 is a front view of the exchange arm shown in a cutaway view, and FIG. 3 is a view taken along the line AA of FIG. 1, and FIG. FIG. 6 is a side view showing an outer end portion of the exchange arm. 3 ... Swivel axis, 6 ... Exchange arm 14 ... Roller axis, 19 ... Cam follower 20 ... Cam

Claims (1)

[Scope of utility model registration request] 1. A tool dropout prevention device, which is movable in a direction perpendicular to an arm turning axis (3) and is unlocked when a tool is always gripped by being biased in a direction for gripping the tool and when the tool is released. In an automatic tool changer such as a machining center in which a roller shaft (14) is provided in an exchange arm (6), a pin (18) provided at a right angle to the roller shaft.
A cam follower (19) pivotally supported on the exchange device, and a position provided in the exchange device main body in parallel with the swivel surface of the exchange arm, where the exchange arm swivels for gripping or releasing the tool from the standby position to immediately before gripping the tool. An automatic tool changer, comprising: an arcuate cam (20) that engages with the cam follower at the time of turning and retracts the roller shaft, thereby eliminating the interference between the roller shaft and the tool when gripping the tool. Tool gripping mechanism.