GB1565061A - Jigs for use with three-axis measuring machines - Google Patents

Description

(54) IMPROVEMENTS RELATING TO JIGS FOR USE WITH THREE-AXIS MEASURING MACHINES (71) We, BL CARS LIMITED, formerly known as BRITISH LEYLAND UK LIMITED, a British Company of Leyland House, 174 Marylebone Road, London NW1 5AA, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed. to be particularlv described in and by the following statement: This invention relates to jigs for use with three-axis measuring machines. Such machines are used in industrv for threedimensional inspection and checking of engineered items. e.g. pressings and machined parts.

The conventional three-axis measuring machine includes a base plate having a flat.

horizontal surface on which an item to be measured must be supported securelv in a predetermined position. To support irrelyu- larly shaped items, e.g. motor bodv panels.

it is usual practice to employ jigs which have been manufactured to individual requirements. Such jigs typically comprise solid welded structures including a base. a vertic- al support and a template portion at the top of the support. The conventional jig is costly to produce and inconvenient to store for future use.

According to a first aspect of the present invention there is provided a method of setting up a jig for use with a three-axis measuring machine. including the steps of attaching a carrier for a template to the probe of a three-axis measuring machine.

setting said carrier by means of said threeaxis machine at the height required for it to position a template at a desired height. and adjusting the height of a support of said jig for supporting the carrier until said support is of the correct height to support the carrier at said required height when it is released from the machine.

According to a second aspcct of the present invention a jig comprises a support that is adapted to stand upright on a horizontal surface and is adjustable in height, and a template detachably secured to a flat top surface of the support. which surface may be arranged to be horizontal when the support is standing on a flat horizontal surface.

Conveniently. the template is one selected from a library of such templates, each identically adapted to be fitted in a predetermined relative position to the support. For example. the template can be formed with a dove-tail portion that fits a dove-tail recess either in the support itself, or in an adaptor block that is secured to the support.

The support preferably has a flat top which is horizontal when the support is standing on a flat horizontal surface. Thus the requisite height of the support and. in particular. the template can be readily established musing the probe of the three-axis measuring machine. Preferably. a special probe having flat horizontal datum surfaces is used.

A preferred embodiment of the invention will now be described. by way of example, with reference to the accompanying drawing. which is a general perspective view of the jig.

Referring to the drawing. the main components of the jig are two substantially identical L-shaped members 1 and 2. made of either wood or aliminium. The member 1 is formed in its longer limb with a hole 3 which registers with a slot 4 formed in the longer limb of the other member 2. The members l and 2 are secured together by a bolt 5 that extends through the hole 3 and slot 4 and carries a wing nut 6.

As illustrated. the shorter limb of the member l supports the jig in its upright position. The two members 1 and 7 can, however. be inverted so that the shorter limb ot the member 2 serves as the base of the jig. Either way, the top and bottom surfaces of the jig are parallel to one another and the jig is adjustable in height by slackening the wing nut 6, relatively displacing the bolt 5 in the slot 4, and re-tightening the wing nut 6.

A template 7, cut to the required form. is formed with a dove-tail portion 8 that fits in a complementary recess in the edge of an adapter block 10 which is secured by a bolt 11 to the shorter limb of the support member 2. The template 7 is secured by screws 9 in a precisclv perpendicular relation to the surface of the adaptor block 10 that is flush with the top surface (as illustrated) of the jig support member 2.

The method of setting-up the jig on the base plate of a three-axis measuring machine is as follows: The support comprising the members l and 2 is placed on the flat. horizontal surface of the base plate in the upright position illustrated. without the template 7 and adaptor block 10 bolted thereto.

The machine is fitted with a probe that carries the block 10. without template fitted, in a precisely horizontal position. The probe and block are brought to a position relative to the base surface of the machine that corresponds precisely to the required position of the template 7. as if the template were fitted to the block.

The support is then adjusted in height, as previously described herein. until the surface 12 of the member 7 (as illustrated) is flush with the bottom surface of the block carried by the probe. If necessary. the adjustment includes an angular adjustment between the members 1 and 2 to obtain the flush contact between the support and block surfaces.

Having bolted the block 10 to the surface 12 and secured the two members I and 2 at the required height by tightening the wing nut 6 and having. moreover. secured the member 1 to the base plate of the machine.

e.g. by means of clamping. a final check is made and the probe is removed from the dovetail portion 8 of the secured block.

The template 7 is then secured to the block at dovetail 8 in position illustrated so that it occupies preciselv the same position just vacated by the probe.

Thus the template 7 is precisely located at the predetermined position relative to the base plate of the machine.

WHAT WE CLAIM IS: 1. A method of setting up a jig for use with a three-axis measuring machine. including the steps of attaching a carrier for a template to the probe of a three-axis measuring machine. setting said carrier by means of said three-axis machine at the height required for it to position a template at a desired height. and adjusting the height of a support of said jig for supporting the carrier until said support is of the correct height to support the carrier at said required height when it is released from the machine.

9 2. A method as claimed in claim 1.

including the step of adjusting the support until it is correctlv arranged to support said carrier in predetermined relation with the horizontal.

3. A method substantiallv as hereinbefore described with reference to the accom panting drawing.

4. A jig comprising a support that is adapted to stand upright on a horizontal surface and is adjustable in height. and a template detachablv secured to a flat top surface of the support. which surface may be arranged to be horizontal when the support is standing on a flat horizontal surtace.

5. A jig according to claim 4. in which the template is mounted on a carrier comprising an adaptor block which is in turn mounted on the flat top of the support. the template being perpendicular to said flat top.

6. A jig substantiallv as hereinbefore described with reference to and as illus united in the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. the jig. Either way, the top and bottom surfaces of the jig are parallel to one another and the jig is adjustable in height by slackening the wing nut 6, relatively displacing the bolt 5 in the slot 4, and re-tightening the wing nut 6. A template 7, cut to the required form. is formed with a dove-tail portion 8 that fits in a complementary recess in the edge of an adapter block 10 which is secured by a bolt 11 to the shorter limb of the support member 2. The template 7 is secured by screws 9 in a precisclv perpendicular relation to the surface of the adaptor block 10 that is flush with the top surface (as illustrated) of the jig support member 2. The method of setting-up the jig on the base plate of a three-axis measuring machine is as follows: The support comprising the members l and 2 is placed on the flat. horizontal surface of the base plate in the upright position illustrated. without the template 7 and adaptor block 10 bolted thereto. The machine is fitted with a probe that carries the block 10. without template fitted, in a precisely horizontal position. The probe and block are brought to a position relative to the base surface of the machine that corresponds precisely to the required position of the template 7. as if the template were fitted to the block. The support is then adjusted in height, as previously described herein. until the surface 12 of the member 7 (as illustrated) is flush with the bottom surface of the block carried by the probe. If necessary. the adjustment includes an angular adjustment between the members 1 and 2 to obtain the flush contact between the support and block surfaces. Having bolted the block 10 to the surface 12 and secured the two members I and 2 at the required height by tightening the wing nut 6 and having. moreover. secured the member 1 to the base plate of the machine. e.g. by means of clamping. a final check is made and the probe is removed from the dovetail portion 8 of the secured block. The template 7 is then secured to the block at dovetail 8 in position illustrated so that it occupies preciselv the same position just vacated by the probe. Thus the template 7 is precisely located at the predetermined position relative to the base plate of the machine. WHAT WE CLAIM IS:

1. A method of setting up a jig for use with a three-axis measuring machine. including the steps of attaching a carrier for a template to the probe of a three-axis measuring machine. setting said carrier by means of said three-axis machine at the height required for it to position a template at a desired height. and adjusting the height of a support of said jig for supporting the carrier until said support is of the correct height to support the carrier at said required height when it is released from the machine.

9

2. A method as claimed in claim 1.

including the step of adjusting the support until it is correctlv arranged to support said carrier in predetermined relation with the horizontal.

3. A method substantiallv as hereinbefore described with reference to the accom panting drawing.

4. A jig comprising a support that is adapted to stand upright on a horizontal surface and is adjustable in height. and a template detachablv secured to a flat top surface of the support. which surface may be arranged to be horizontal when the support is standing on a flat horizontal surtace.

5. A jig according to claim 4. in which the template is mounted on a carrier comprising an adaptor block which is in turn mounted on the flat top of the support. the template being perpendicular to said flat top.

6. A jig substantiallv as hereinbefore described with reference to and as illus united in the accompanying drawing.