GB2142563A - Locating device - Google Patents

Abstract

A locating device including holding means (19), for locating the holding means in a desired orientation about an axis with respect to a member (28), comprises: means (26) for moving the holding means with respect to the member to position the first member on the axis; means (10, 12, 13, 14) for producing relative rotation between the holding means and the member about the axis; and sensing means (15, 30) for sensing when the holding means is in the desired orientation by sensing a point on the member, the device being such that the holding means can be stopped in response to such sensing, with the holding means in the desired orientation. <IMAGE>

Description

SPECIFICATION Locating device The present invention relates to a locating device, for example for use with a machine tool.

Known single and multi-spindle automatic devices are at a disadvantage when used on a machine such as a lathe, on which more than one operation is required. On completion of a cycle, the or each spindle stops in a random position which makes it very difficult to automate the loading of components such as workpieces into the machine. Manual labour is required to load components, into chuck jaws in the case of a lathe, and, as cycle times are usually fairly short, one person is required for each machine.

According to the present invention there is provided a locating device including holding means, for locating the holding means in a desired orientation about an axis with respect to a member, the device comprising: means for moving the holding means with respect to the member to position the first member on the said axis; means for producing relative rotation between the holding means and the member about the said axis; and sensing means for sensing when the holding means is in the said desired orientation by sensing a point on the said member, the device being such that the holding means can be stopped in response to such sensing, with the holding means in the said desired orientation.

When the locating device is used in conjunction with a machine tool, such as a lathe, the said member could comprise chuck jaws of the lathe, and could be provided with a projecting member at said point for being sensed by the said sensing means.

For a better understanding of the present invention, and to show how the same may be carried into efect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows diagramatically by locating device for use with a lathe; Figure 2 is a side view of a simulated machine tool fitted with a further example of a locating device; Figure 3 is a partial view on arrow C in Figure 2; Figure 4 is an enlarged view on arrow A in Figure 2; and Figure 5 is an enlarged view on arrow B in Figure 1.

Figure 1 shows a chuck 1 of an automatic lathe, which is provided with a projecting pointer member 2. A workpiece 3 is to be loaded into the chuck jaws by means of a locating device, generally designated by reference numeral 4.

The locating device 4 comprises a head or gripper 5 for holding the workpiece 3; a sensor 6; an electric motor 7 for rotating gripper 5; and an automatic pick and place mechanism 8, for example a robot arm, for holding and moving the gripper 5 and motor 7.

In use of the device 4, the mechanism 8 moves the gripper 5 holding the workpiece 3 so that the latter is symmetrically on the centre linex-x of chuck 1. The gripper 5 is then rotated by the motor 7 about line x-x until the sensor 6 detects the member 2. The rotary drive then stops, and the workpiece 3 is inserted in the jaws of the chuck by extending the gripper 5, using the mechanism 8. Thus the workpiece is automatically inserted correctly in the jaws of the chuck 1,the arrangement being such that when the sensor 6 detects the member 2, the workpiece 3 is in the correct position, relative to the jaws, for insertion into the latter. The whole device 4 then retracts using the mechanism 8 and the lathe can continue its cycle of operation.

The member 2 can be simply fixed to the chuck (or instead the spindle) of an existing lathe, or other machine tool, and the sensor can be one for sensing electrically, optically or pneumatically depending on the operating conditions.

It will be appreciated that a locating device such as device 4 could also be used to orientate the operating tool of a machine with respect to a fixed workpiece.

Also, the device could be used for the removal of a finished workpiece.

Referring to Figures 2,3,4 and 5, reference numeral 10 designates an electric motor for rotating a disc 11 via a timing belt pulley 12, a timing belt 13 and a timing belt pulley 14. Disc 11 carries a sensor 15 and has slots 16 and 17 for co-operating with a sensor 18. Holding means 19 can rotate with disc 11 and in Figure 2 holds a component 20, holding being assisted by magnets 21. A pneumatic cylinder 22 is provided for displacing holding means 19 from left to right and vice-versa in Figure 2, independently of disc 11, via a coupling 23 and a shaft 24. The foregoing items are caried on a slide assembly 25 which can be displaced in a direction at right angles to the plane of the drawing in Figure 2 by a pneumatic cylinder 26. The disc 11 can be displaced from left to right and vice-versa in Figure 2 by the action of a pneumatic cylinder 27.

Reference numerals 28 designate machined blocks which simulate the jaws of a chuck of a machine tool, which blocks may be rotated by a hand-wheel 29 simulating the means for rotating the chuck. Reference numeral 30 designates a probe which rotates with blocks 28. Reference numerals 31,32 and 33 designate ball-bearings.

For controlling the motor 10 and the cylinders 22, 26 and 27 via their pneumatic lines, there is provided control circuitry schematically designated by a block 34 and fed with signals from the sensors 15 and 18.

The operation of the device is as follows.

Under the control of means 34, motor 10 rotates to find a datum position, this occurring only on starting.

This is done by rotating disc 11 for 1/2 second in one direction, then rotating it in the opposite direction until slot 16 is sensed by sensor 18 and then rotating it slowly until slot 17 is sensed by sensor 18, the disc 11 being stopped in this position.

The piston of cylinder 26 is retracted to put slide assembly 25 on the centre line of the device, against a stop.

The piston of cylinder 27 is moved a preset distance from right to left to a position in which probe 30 is on the locus of sensor 15.

Motor 10 rotates until sensor 15 senses that probe 30 is within sensor 15, motor 10 being stopped in this condition.

The piston cylinder 22 is moved from right to left a preset distance to insert the component (represented by item 20) held by holding means 19 into the chuck jaws (these simulated in the device by machined blocks 28).

The pistons of cylinders 22 and 27 are moved from left to right in Figure 2 preset distances to retract, and the piston of cylinder 26 is extended.

Claims (13)

1. A locating device including holding means, for locating the holding means in a desired orientation about an axis with respect to a member, the device comprising: means for moving the holding means with respect to the member to position the first member on the said axis; means for producing relative rotation between the holding means and the member about the said axis; and sensing means for sensing when the holding means is in the said desired orientation by sensing a point on the said member, the device being such that the holding means can be stopped in response to such sensing, with the holding means in the said desired orientation.

2. A locating device according to claim 1, wherein the means for moving the holding means comprises a cylinder and piston arrangement.

3. A locating device according to claim 1 or 2, wherein the means for producing relative rotation comprises a motor acting to rotate the holding means.

4. A locating device according to any preceding claim, wherein the sensing means comprises a probe and a sensor for sensing the probe, one of which is rotated relative to the other by the means for producing relative rotation, the holding means being in the said desired orientation when the probe is in a given position with respect to the sensor.

5. A locating device according to claims 3 and 4, wherein the sensor rotates with the holding means and the probe in use of the device is fast with the said member.

6. A locating device according to claim 5, wherein the sensor is on a disc which rotates with the holding means.

7. A locating device according to claim 4, 5 or 6, including means for producing relative movement between the sensor and the probe in a direction parallel to the said axis before such relative rotation occurs, whereby the probe and the sensor are in such positions relative to each other that the sensor is capable of sensing the probe as a result of such relative rotation.

8. A locating device according to claim 7, wherein the means for producing relative movement between the sensor and the probe in a direction parallel to the said axis comprises a cylinder and piston arrangement.

9. A locating device according to claim 7 or 8, including means for bringing the sensor to a datum angular position before such relative movement in a direction parallel to the said axis occurs.

10. A locating device according to claim 9, as dependent on claim 5 or 6, wherein the means for bringing the sensor into a datum angular position comprises means for bringing the holding means into a datum position.

11. A locating device, substantially as herein described with reference to Figure 1 of the accompanying drawings.

12. A locating device, substantially as herein described with reference to Figures 2 to 5 of the accompanying drawings.

13. A machine tool which includes a locating device as claimed in any one of the preceding claims.