GB2239618A

GB2239618A - A device for mounting a workpiece on a lapping machine

Info

Publication number: GB2239618A
Application number: GB9000457A
Authority: GB
Inventors: Roger Edward Lane
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-01-09
Filing date: 1990-01-09
Publication date: 1991-07-10
Also published as: GB9000457D0

Abstract

A device for mounting a workpiece on a lapping machine comprises a support 20 secured to a fixed part of the machine, first 22 and second 27 pivotal arms and first 24 and second 30 wheels for engagement with the rotating abrading disc of the machine and the workpiece or workpiece holder 15 or carrier respectively. The wheels 24, 30 are connected by drive belts 33, 34 and compound pulley 32 so that the workpiece is rotated at a constant relative speed to that of the abrading disc. <IMAGE>

Description

DEVICE FOR MOUNTING A WORKPIECE ON A LAPPING MACHINE It is known, for example from US-A-2408334, to lap the radially extending faces of a shouldered component by providing an abrading disc having coaxially-extending lands which engage the face to be lapped and between which a stem or shaft of the component extends with clearance. The axis of the component is fixed relative to that of the disc and both the disc and workpiece are rotated in the same directions and preferably at a fixed speed ratio. In the above prior art drive to both the lapping disc and the component is effected by a system of pulleys.

It is an object of the invention to provide a device which may readily be mounted on a lapping machine, whatever the method of drive to the abrading disc of that machine, and in which a component to be lapped is rotated at a speed which has a constant relationship to that of the abrading disc.

According to the invention there is provided a device for rotating a workpiece in contact with a rotatable abrading disc of a lapping machine, comprising a support, means for securing said support to a relatively fixed part of the machine, first and second wheels mounted on said support for engagement respectively with circumferential surfaces of said disc and said workpiece, or a carrier for said workpiece, and a driving connection between said first and second wheels.

One embodiment incudes first and second arms mounted on said support for pivotal movement about axes parallel to the axis of rotation of said disc, said first and second wheels being mounted at ends of said first and second arms respectively.

In a particular embodiment said second arm is mounted intermediate its ends and supports a third wheel at an end remote from that on which said second wheel is supported, said third wheel being engageable with a circumferential surface of said workpiece, or a carrier therefor.

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a plan view of a lapping machine with a device according to the invention mounted thereon, Figure 2 is a section, to a larger scale, on line 2-2 in Figure 1, and Figure 3 is a view on arrows 3-3 in Figure 2.

As shown in Figures 1 and 2 a lapping machine includes an abrading disc 10 which is rotatable about a vertical axis and has a plurality of annular lands 11 concentric with the rotational axis of the disc 10. A deep annular groove 12 is bounded by two of the lands 11. Secured to a fixed part 13 of the machine is a device for locating and rotationally driving a holder 15 for a workpiece 16. In the present example the workpiece 16 is shouldered. A spindle 17 of the workpiece 16 extends within the groove 12 so that a face 18 which is to be lapped can engage two of the lands 11. The axial dimensions of the holder 15 are such that it does not engage the lands 11. The holder 15 frictionally engages the workpiece 16 by means of an elastomeric ring 19, and the workpiece 16 is urged into contact with the disc 10 by its weight and that of the holder 15.

The device 14 comprises a plate 20 having a slot 21 through which a bolt passes to secure the plate 20 adjustably to the fixed part 13 of the machine. An arm 22 is mounted on the plate 20 for movement about a pivot 23 whose axis is parallel to the axis of rotation of the disc 10. The end of the arm 22 carries a friction wheel 24 which is biased into engagement with the circumference of the disc 10 by a spring 25 between the arm 22 and the plate 20. A pulley 26 is secured to the wheel 24 for rotation therewith.

A further arm 27 has a slot 28 intermediate its ends, the slot 28 being engageable with a pivot pin 29 whose axis is parallel to that of the pivot 23. A friction wheel 30 is mounted on one end of the arm 27 and incorporates a pulley. A steadying wheel 31 is mounted on the other end of the arm 27. The slot 28 allows the arm 27 to be pivotally and longitudinally adjusted to bring the wheels 30, 31 into engagement with the periphery of the workpiece holder 15. A compound pulley 32 is mounted on the plate 20 and has its larger element coupled by a driving band 33 to the pulley 26, and its smaller element coupled by a driving band 34 to the pulley on the friction wheel 30. The pulleys are sized so that the holder 15 and workpiece 16 rotate at approximately twice the speed of the disc 10. It will be apparent that any other desired speed relationship may readily be effected.

As seen in Figures 2 and 3 the radial dimension of the groove 12 is only slightly larger than the diameter of the workpiece spindle 17 so that rotation of the workpiece 16 causes the lands 11 on either side of the groove 12 to sweep the whole of the radially-extending face 18 of the workpiece as the latter rotates. Rotation of the disc 10 in the direction indicated in Figure 1 suffices to urge the workpiece holder 15 against the wheels 30, 31 and thereby to maintain its position and driving contact.

It will be apparent that more than one of the devices 14 may be mounted on the stationary part 13 of the machine, once the appropriate abrading wheel 10 is in position.

Claims

A DEVICE FOR MOUNTINGA WORKPIECE ON A LAPPING MACHINE

PA TENTAPPLICA TION NUMBER 9000457 CLAIMS 1. A device for mounting a workpiece on a lapping machine in which the component to be lapped is driven from the abrading disc of the machine and is rotated at a speed which has a constant relationship to that of the abrading disc.
2. A device for mounting a workpiece on a lapping machine as claimed in claim 1 wherein a support is provided to fixed part of machine.
3. A device for mounting a workpiece on a lapping machine as claimed in claim 1 or claim 2 wherein first and second drive wheels are attached to the said support and provide engagement with the circumfrential surfaces of the said disc and the said workpiece or a workpiece holder or carrier.
4. A device for mounting a workpiece on a lapping machine as claimed in claim 2 or claim 3 wherein for mop a driven connection is provided between the first and second drive wheels.
5. A device for mounting a workpiece on a lapping machine as claimed in claim 3 or claim 4 wherein first and second arms are mounted on said supportforpivitol movement about an axis parallel to the axis of rotation of the said disc.
6. A device for mounting a workpiece on a lapping machine as claimed in claim 5 wherein the said first and second wheels are mounted at the ends of the said first and second arms respectively
7. A device for mounting a workpiece on a lapping machine as claimed in claim 6 wherein a third wheel is attached to the second arm at the end remote from that on which the second wheel is supported and said third wheel is engageable with the said workpiece or workpiece holder or carrier.
8. A device for mounting a workpiece on a lapping machine as described in claims 1 through 7 with reference to FIG 1.