GB2315553A - Co-ordinate pointing device for use in marking sheet material - Google Patents

Abstract

A coordinate pointing device for use in the marking, such as by drilling, at any desired position or positions within the range of the device, sheet material (5,fig.2), has two beams 11a, 11b, having straight edges 23a, 23b, respectively, the Y-beam 11a, with a carriage 45 adapted to carry the beam 11b in locating means (49; Fig.4) and being dispaceable along the Y-beam, the X-beam 11b with a carriage (121) dispaceable therealong, and with displacement sensor arrangements (35, 37) respectively, for sensing movements of their respective carriages with respect to a datum D1,D2, from which the X and Y co-ordinates for any position within the area of the sheet material may be gauged.

Description

Coordinate Pointing Devices This invention relates to coordinate pointing devices.

It is particularly concerned with a novel configuration for a coordinate pointing device for use in the marking, such as by drilling, at any desired position or positions within the range of the device, of bodies of sheet material.

There are numerous reouirements for devices in accordance with the invention. Such devices have application wherever e r e v e r there exists an on-going demand for a relatively inexpensive, light-weight, and, hence, portable, means for marking sheet material, whether metal or of any other material.

Devices in accordance rJith the invention have a particular value in the marking panels, even large panels, in situ, at a variety of positions across the panel. It, therefor, has valuable applications in such environments as work-shops and garages and is a valuable aid in the drilling of panels at a multiplicity of accurately predesignated positions in the course of the fitting of such panels in domestic and office & c. environments.

According to the invention, a coordinate pointing device comprises: a first beam providing a first straight edge; mounted on said first beam, a first carriage, being a carriage constrained for movement along said first beam parallel to said straight edge; secured rigidly to said first carriage, a second beam providing a second straight edge, being an edge at right angles to said first straight edge; mounted on said second beam, a second carriage, being a carriage constrained for movement along said second beam parallel to said second straight edge; and in which, said second carriage incorporates means defining an axis (hereinafter referred to as "the coordinate pointing axis") being an axis orthogonal to the X-Y plane defined by the to beams; mounted on the first carriage, there is first positionencoder means for sensing displacement of said first carriage in one said coordinate direction with respect to a datum position defined in said first beam; and, mounted on the second carriage, there is second position-encoder means for sensing displacement of said second carriage in te other said coordinate direction wit i t h respect to said datum position; and, the functional inter-relationship of the several aforementioned component parts of the device is such that movement of the first and second carriages parallel to the orthogonally related straight edges of their respective beams, causes said first and second encoders to display, the one, the X-coordinate, the other, the Y-coordinate value of the coordinate pointing axis with respect to said datum position.

Preferably, said first and second encoder means each comprise: a rotary encoder device; a rotary encoder read-out for displaying the setting of said encoder device; a drive pulley associated with said encoder device; first and second idler pulleys associated with said drive pulley; and a substantially inextensible line extending under tension along the spar with which said encoder device is associated; the several aforementioned parts of each encoder device being such that the tensioned line thereof extends between its fixed ends in rotary driving contact with, successively, the first idler, a pulley of the rotary encoder device, and the second idler.

Preferably, also, each of said first and second beams is constituted as a beam of the kind produced using the method claimed in the claims and, particularly, claim 9 of Applicants co-pending 01K patent Application No.

Preferably, each of the first and second beams, the rod of the spar is a nominally straight tube.

A coordinate plotting device in accordance with the invention is hereinafter described, not to a consistent scale throughout, with reference to the accompanying drawings in which: Fig.l shoves a beam of a preferred construction employed in the coordinate pointing device of the present invention; fig.2 is a pictorial diagram of the coordinate pointing device; Fig.3 is a pictorial diagram of the coordinate pointing device of Fig.2 but with the cover removed; Fig.4 is a pictorial diagram of the Y-beam assembly of the device of Fig.3; Fig.5 is a corresponding pictorial diagram of the Xbeam assembly of the device of Fig.3; Fig.6 shows an end view of the Y-beam assembly; Fig.7 shows a section taken on VII----VII of Fig.4; Fig.8 shows a part section of Fig.4, being a section taken on VIII-VIII of that Figure; and, Fig.9 illustrates features of encoder devices employed in the pointing device.

Before proceeding to a description of a preferred construction of a coordinate pointing device, in accordance with the invention, reference should be had to Applicants co-pending UK Patent Application GB No.

where a description is given of a method of construction of a preferred form of beam to be incorporated in said preferred coordinate pointing device of the present invention.

The preferred beam construction mentioned above is, for convenience, shown in Fig.l from which it will be seen that the spar 11 comprises a multiplicity of generally rectangular block elements 13 which are disposed at intervals along a tube 15 posted through passages 17 each of which is oversized in relation to the diameter of the tube 15. The block elements 13 and the tube 15 have been secured together ith the surfaces 19 of the block elements 13 held co-planar using a master jig (not shown), all as described in the specificaton of the aforementioned co-pending Patent Application, using, typically, a filled epoxy resin introduced, in the liquid state, into the mismatch spaces between the tube 15 and the encompassing walls of the oversized passages 17 and thereafter cured, in situ, in the master jig. A thin rectangular plate 21 having parallel length-vise extensive straight edges 23a, 23b, respectively, is secured, as by dowels and/or screws (not shown), to the co-planar surfaces 19 of the block elements 13.

The beam so formed is inherently rigid and is substantially proof against twisting. The block elements 13 and the tube 15 are of a hard aluminium alloy, duralumin, say, and the plate 21 is of steel. The entire spar assembly is lightweight by comparison with straight edge devices customarily employed, thereby rendering it particularly suitable for application in the invention of the present Application.

The coordinate pointing device (Figs.2 and 3) comprises: first and second beams lla, llb, respectively, (hereinafter respectively referred to as the Y-beam and the X-beam) each spar being of the kind referred to above, and more exhaustively dealt with in the co-pending Patent Application referred to previously; between the Y and X beams lla, llb, a first carriage 25 vjh i c h is adapted, as hereinafter described, for displacement along the Y-beam lla and to which the X-beam 11b is detachably rigidly attached, being supported orthogonally with respect to the Y-beam lla; a second carriage 27 adapted for displacement along the X-beam llb; coordinate pointing-axis defining means 29 carried by said second carriage 25 and defining a pointing axis P---P.

a first displacement encoder arrangement including a battery-powered first rotary optical encoder device 31 ujhich is carried by the first carriage 25, being an optical encoder device sensitive to displacement of said first carriage 25 along the Y-beam lla; and a second displacement encoder arrangement including a battery-powered second rotary optical encoder device 33 which is carried by said second carriage 27, being an optical encoder device sensitive to displacement of said second carriage 27 along the X-beam llb.

The aforementioned displacement encoder arrangements each include, in addition to said rotary optical encoder arrangements 31, 33, respectively, battery-pored first and second encoder read-out devices 35, 37, respectively, for displaying the encoder device displacement settings, flying leads, as 39, being provided to connect the encoder arrangements 31, 33, to their respective read-out devices 35, 37. Other features of the displacement encoder arrangements will be further described hereinafter.

Te Y- and X-beams lla, llb, are respectively contained within housings 39, 41, and the read-out devices 35, 37, are mounted on brackets, as 43 (Fig.2).

Considering the first or Y-carriage 25 in greater detail, this comprises: a carriage platform 45; carriage-travel constraint means 47; locating means 49 for attachment of the X-axis bam 23 to the carriage 25 and the rotary optical encoder arrangement 31.

The Y-carriage travel constraint means 47 comprises means for supporting the carriage 25 clear of the upper surface 51 of the thin plate 21a of the Y-beam lla, and means for constraining the carriage 25 for movement parallel to the longitudinal direction of the latter beam.

The means for supporting the Y-carriage 25 clear of the thin plate 21a of the Y-beam ila comprises, in the example, four grou?s, as 5 3, of tyred wheel arran^ements respectively disposea near the four corners of the Y-carriage platform 45. Each of the tyred eel arrangements comprises a eel carrier 55 and to tyred wheels 57a, 57b, respectively carried on spindles or axles 59a, 59b, respectively, projecting, the spindles or axles 59a from the side edges, as 61, of the carriage platform 45, the spindles or axles 59b from the eel carriers 55, the arrangement in each tyred wneel arrangement 53 being such that the tyred wheels 57a are in frictional rolling contact with the u?per surface 63 of the carriage platform 45 whilst maintaining the required clearance bet.jeen the 1 lower surface of tile platform 45 and the upper surface 51 of the beam plate 2ia, whilst the tyred wheels 59b are in frictional rolling contact with the under surface of said beam plate.

The means for constraining the Y-carriage 25 for movement parallel to the longitudinal direction of the Y-beam lia comprises, in the example, a further four t y red wheel group arrangements, as 65, respectively located, as with the four wheel group arrangements 53, near the four corners of the Y-carriage platform 5. Each of the heel groups 65 comprises a wheel carrier 67 and a single tyred heel 69.

The tJheel carriers 57 are secured, as appropriate, to the side edges, as 61, of the Y-carriage platform 45 and the tyred wheels 69 are supported from their respective carriers 67 by their spindles or axles 71, being in frictional rolling contact with an adjacent one of the parallel side edges 23a or 23b, as the case may be, of the Y-beam plate 21a.

The locating means 49 for attachment of the X-beam 1lb to the Y-axis carriage 25 is constituted by a cantilevered beam structure 73, produced using the same method as that employed in the production of the beams lla, llb, and being, in essence, two such beams ganged together, side-by side with a spacing therebetween appropriate for the reception of the X-beam llb.

ore specifically, the locating means 9 comprises first and second duralumin blocks 75, 77, respectively, each having upstanding end-post portions, 79a, ela; 79b, Blub, defining centrally located channels 83, 85, respectively, which extend in the fore and aft direction thereacross.

Each of the channels 83, 85, are bounded by first and second opposed flat and parallel surfaces, as 87a, 87b, respectively formed on the end-post portions 79a, 81b; 790, 81b, and first and second duralumin tubes 39a, 89b, respectively, posted, as ith the tubes 15 of the beams Ila, llb, through oversized passages through the blocks 75, 77, corresponding surfaces 87a or 87b, as the case may be, of said blocks being held co-planar by cured epoxy resin reinforced, perhaps, by crossed dowels, the fabrication of the locating arrangement being, as with the spars lla, llb, performed ii th tune block arrangement located in a master jig.

The block 77 is secured to the carriage platform 45 at a side margin thereof. Of the upstanding end-post portions 79a, 81a; 79b, 81b, on which the co-planar flat surfaces 87a and 87b are to be found, to 79a, Bib, are provided iith upstandin stud stud portions, as 91. The two other stub arm portions 79b, 81a, have upstanding threaded elements, as 93 each provided Vdith a nut as 95.

The rotary encoder arrangement 31 comprises: a channeled block 97; an optical encoder disc 99; a drive pulley 101 and associated first and second idler pulleys 103, 105; and an encoder drive arrangement. The channeled block 97 is mounted on the upper surface 3 of the Y-carriage platform 45. The optical encoder disc 99 is between the channel lolls of the block 97 and is carried on a spindle 107 for angular displacement about the axis thereof. The drive pulley 101 too is carried on the spindle 107 whilst the first and second idler pulleys 103, 135, are rotatable about spindles or axles, as flu9, upstanding from the carrier platform 45.

The encoder drive arrangement comprises: first and second line anchorage devices, as 111, which are fixed to the Y-beam plate 21a at the ends thereof, and which project proud of the upper surface 63 of the carrier platform 45; and a substantially inextensible line 113 terminating at each end at line tension adjuster threaded elements, as 115, and passing, as shown, around said idler and drive pulleys in frictional driving engagement therewith.

The block elements 13 of the Y-beam lla differ somewhat from those of beam 11 of Fig.l in that they are formed, as by machining, such as to provide side lug portions, as 117.

Attached to the lug portions 115 there are two sheet clamp elements 119, the to e ndmo st ones of which are shown in Fig.4. The clamp elements 119 serves to hold sheet material S (Fig.2) about the surface area of .jhich the coordinate pointing axis defining means 29 is to be moved in the course of plotting coordinate positions at which the sheet material S is to be marked, as by the drilling at each such coordinate position, of a hole. The clamp elements 119 serve also as datum-defining means for the sheet material, alignment of an edge of the sheet material S 'jith a orthogonal datum edges Dl, 2, respectively, provided by clamp elements 119 defining an origin from which the X and Y coordinates for any position swithin the area of the sheet material S may be gauged.

Turning next to the X-carriage 27 of the co-ordinate plotting device, this comprises: a platform 121; carriagetravel constraint means 123; and the rotary optical encoder device 33.

The X-beam llb has, in addition to block elements, as 13, located, at intervals therealong, tLtJo block elements 1 3 a, 13b, respectively, formed each z!ith first and second laterally projecting lug portions 125. The block elements 13a, 13b, are located along the X-beam llb towards one end thereof and are spaced apart therealong by the same distance as that separating the upstanding post portions 79a,81a; 79b,olb, respectively, of the blocks 75, 77, of the Y-beam lla.

The block elements 13a, 13b, of the X-spar are, moreover, complementary in shape to that of the channeled blocks 75, 77. In consequence, at assembly of the Y- and X-beams, and as shon, particularly, in Fig.3, the lug portions 125 of the block elements 13a, 13b, of the X-beam llb sit upon the upstanding post portions 79a,81a;79b,81b, of said channeled blocks 75, 77, the stud portions 91 and the threaded elements 93 of the X-beam blocks 13b being received in passages 127 formed in said lug portions 125.

ith the X-spar 11D so seated with respect to the Y-beam gila, and smith the nuts 95 screwed along the threaded elements 93 so as to bear upon the lug portions 125, the Xbeam llb is firmly secured to the Y-beam lla. The complementary fit of the blocks 13b of the X-beam with the channeled blocs 75, 77 of the Y-beam ensures that the two beams extends perpendicular to one another.

The X-carriage travel constraint means 121 is essentially the same as the Y-carriage travel constraint means 47.

There are, as before, means for supporting the X-carriage 27 clear o the, in the case of the X-carriage, lovJer surface of the beam plate 21b of the spar 11b, and means for constraining the carriage 27 for movement parallel te the longitudinal direction of said beam.

Further, the means for supporting the carriage 27 clear of the beam plate 21b comprises, in the example, four groups of tyred eel arrangements respectively disposed near the four corners of the carriage platform 121. Each of the tyred wheel arrangements comprises, as before, a el carrier 131 and to tyred wheels 133a, 133b, respectively, these being carried, the wheels 129a on spindles or axles projecting from the side edges 135 of the carriage platform 121, the wheels 129b on spindles or axles projecting from the wheel carriers 131. The arrangement in each wheel group 129 is such that the tyred wheels 133a, 133b of the several wheel groups are respectively in frictional rolling contact *^itn the major of the beam plate 21b, a certain clearance being maintained between the carriage platform 119 and the lower surface of said X-beam plate 21b.

The means for constraining the X-carriage 27 for movement parallel to the longitudinal direction of the X-beam llb comprises, in the example, a further four tyred wheel groups, as 137, respectively located, as with the four wheel groups 129, near the four corners of the carriage platform 121. Each of the wheel groups 137 comprises a wheel carrier, as 139, and a single tyred vi h e e 1, a 5 141. The wheel carriers 139 are secured, as appropriate, to the side edges, as 135, of the carriage platform 121 and the tyred wheels 141 are supported from their respective carriers 139 by their spindles or axles, being in frictional rolling contact with an adjacent one of the parallel side edges 23a or 23b, as the case may be, of the beam plate 21 of the beam llb.

First and second brake arrangements devices 143, 145, respectively, serve to hold the carriages 45, 121, stationary except en it is desired to displace said carriages from one position to another along their respective beams 21a, 21b. The brake arrangements each comprise (Fig.8) : a transverse passageway 147, being an extension of a passage adapted to receive a wheel carrier 67; within the passageway 147, a plunger 149 having an inclined surface 151; within a portion of the passageway 147 beyond the end of the plunger 149, a compression spring 153; seated within a side aperture of the wall of the passageway 147, a friction pad 155 having, within the passageway 147, an inclined surface 157. and a brake manual member 159 extending through the carriage 45 and being adapted, by rotational movement thereof, to displace the plunger 149 such as, by y spring compression, to cause pressure between the inclined surface 151 of the plunger 149 and the inclined surface 157 of tne friction pad 155 to relax, the friction pad 155 being thereby freed from frictional braing engagement with, in the example, the beam plate 21a.

The rotary encoder arrangement 33 is the same as the encoder arrangement 31. It has, as before, a channeled block, an optical encoder disc, a drive pulley, associated first and second idler pulleys and an encoder drive arrangement in the form of an inextensible cord threading tine several pulleys and being under tension e̳t.^Jeen end anchor means essentially the sarge as e before, carried on the beam plate 21b at the ends thereof.

The encoder arrangements 31, 33, are such that displacement of the Y-carriage 45 along the Y-beam 21a by a given amount gives rise to a corresponding read-out value at the read-out device 35 and displacement of the X-carriage by a given amount along the X-beam 21b gives rise to a corresponding read-out value at the read-out device 37.

In use, the rectangular body of sheet material is clamped to te device by means of the clamp elements 119, a corner of the sheet material being located by the datum defining surfaces D1, D2, of said clamp devices.

By displacing the Y-carriage and the X-beam 21b, carried thereby, in either sense, along the Y-beam 21a and displacing the X-carriage 27, in either sense, along the Xbeam 2ib, the coordinate pointing axis P---P may be made to coincide with any X and Y coordinate position of the sheet material, being coordinate positions (the sheet material S having being aligned with the datum defining surfaces 91, D2) indicated by the read-out devices 35 and 37.

The coordinate pointing-axis defining means 29 comprises a member 161 outstanding from the X-carriage 121 and provided it an aperture 163 fitted with an hard bush (not shown) adapted to receive a marking instrument (not S h son) having a close fit tnerewithin. The aforesaid marking instrument might be a pointed rod or it might be a drill bit held in the chuck of a portable drill, the marking at desired positions of sheet material clamped as previously indicated to the coordinate pointing device being drilled holes formed by drill action on the shaeet material.

Claims (5)

CLAIFIS

1. A coordinate pointing device which comprises: a first beam providing a first straight edge; mounted on said first beam, a first carriage, being a carriage constrained for movement along said first spar parallel to said first straight edge; secured rigidly to said first carriage, a second beam providing a second straight edge, being an edge at right angles to said first straight edge; mounted on said second beam, a second carriage, being a carriage constrained for movement along said second beam parallel to said second straight edge; and in which, said second carriage incorporates means defining an axis (hereinafter referred to as "the coordinate pointing axis"), being an axis orthogonal to the X-Y coordinate plane defined by the to beams; said first carriage incorporates first position-encoder means for sensing displacement of said first carriage in one said coordinate direction ..itn respect to a datum position defined in said first beam; and, said second carriage incorporates second position-encoder means for sensing displacement of said second carriage in the other said coordinate direction vJith respect to said datum position; and, the functional inter-relationship of the several aforementioned component parts of the device is such that movement of the first and second carriages parallel to the orthogonally related straight edges of their respective beams, causes said first and second encoders to display, the one, the X-coordinate and, the other, the Y-coordinate value of the coordinate pointing axis with respect to said datum position.

2. A coordinate pointing device as claimed in claim 1 in ic said first and second encoder means each comprise: a rotary encoder device; a rotary encoder read-out for displaying the setting of said encoder device; a drive pulley associated r!itn said encoder device; first and second idler pulleys associated with said drive pulley; and a substantially inextensible line extending under tension along the spar with which said encoder device is associated; and the several aforementioned parts of each encoder device are such that the tensioned line thereof extends beten its fixed ends in rotary driving contact 'iJith, successively, toe first idler, a pulley of the rotary encoder device, and the second idler.

3. A coordinate pointing device as claimed in claim 1 or 2 in which each of said first and second beams is constituted as a beam produced using the method claimed in any of claims 1 to 7 of Applicants co-pending UK patent Application No.

4,. A coordinate pointing device as claimed in claim 3 in which in respect of each of the first and second beams, te rod of the beam is a nominally straight tube.

5. A coordinate pointing device substantially as hereinbefore described mJith reference to the accompanying drawings.