GB1579611A

GB1579611A - Flexible track

Info

Publication number: GB1579611A
Application number: GB1764578A
Authority: GB
Original assignee: PANTATRON SYSTEMS Ltd
Current assignee: PANTATRON SYSTEMS Ltd
Priority date: 1978-05-04
Filing date: 1978-05-04
Publication date: 1980-11-19

Description

(54) FLEXIBLE TRACK (71) We, PANTATRON SYSTEMS LIMITED, a British company of 34, Fern Street, Motherwell ML1 2AJ, Great Britain, 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 particularly described in and by the following statement: This invention relates to apparatus for use in positioning or moving an instrument or tool with reference to the surface of a workpiece.

In positioning or moving an instrument or tool with reference to the surface of a workpiece, it has been proposed to mount the instrument or tool on a carriage and to provide for the carriage to co-operate with a track or guideway to be stationed on or adjacent the workpiece surface. Where the workpiece surface is curved, difficulty has been experienced in matching in a satisfactory way the curvature of the track or guideway with that of the workpiece surface.

An object of the present invention is to obviate or mitigate the aforesaid difficulty.

According to the present invention, there is provided apparatus for use in positioning or moving an instrument or tool with reference to the surface of a workpiece, comprising an assembly of at least two mutually parallel elongate flexible elements, first and second means for locating the elements relative to one another with reference to their longitudinal direction, said first and second locating means being mutually longitudinally spaced, at least one of said first and second locating means being operable to permit or effect shifting of one element relative to the other in the longitudinal direction whereby the assembly can be set to and retain a desired curvature, and a flexible track or guideway incorporated in said assembly for co-operating with a carriage for carrying an instrument or tool.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure I is a diagrammatic side elevation of an assembly incorporating a flexible track or guideway in accordance with the present invention; Figure 2 is a fragmented plan view of part of Figure 1 to a larger scale; Figure 3 is a sectional side elevation on the line III-III in Figure 2: Figure 4 is a sectional end elevation on the line IV-IV in Figure 2; Figure 5 is a diagrammatic plan view of a tool-positioning carriage co-operating with part of an assembly as shown in Figures 1 to 4; and Figure 6 is a diagrammatic part-sectional end elevation on the line VI-VI in Figure 5.

In the drawings, a flexible track member 10 is incorporated in an assembly of two mutually parallel elongate flexible elements in the form of face-to-face strips 11 and 12 of a resiliently flexible plastics material. The track member 10 is also a strip and is generally of the same width as the strips 11 and 12. Track member 10 is made of stainless steel and its ends are indicated in Figures 1 to 3 by arrows A. At spaced intervals therealong, the assembly is fastened by means of headed connectors or studs 13 each of which extends through holes in the strips 11 and 12 which are elongate in the longitudinal direction of the assembly with a view to allowing lontitudinal shifting of one strip relative to the other as explained below. In Figure 1, the positions of the connectors 13 are indicated by their centre lines.

Means for locating the strips 11 and 12 relative to one another with reference to their longitudinal direction are provided in the form of first and second screwed adjusters 14 each of which is operable to effect shifting of one of the strips relative to the other in the longitudinal direction. It will be appreciated that such shifting will induce curvature in the assembly proportional with the degree of differential in the effective lengths of the upper and lower sides of the assembly constituted by the strips 11 and 12.

A third locating means in the form of a headed connector or stud 15 is provided at the mid-point along the assembly. The connector 15 is similar to the connectors 13 except that it extends through circular holes in the strips 11 and 12 thereby to locate longitudinally the one strip relative to the other. Thus, by virtue of the provision of the intermediate locating means or connector 15, the adjacent half-lengths of the assembly can adopt and retain mutually different curvature including reversal of curvature by appropriate operation of the screwed adjusters 14.

The assembly is provided with attachment means in the form of suction cups 16 for attaching the assembly to a smooth surface of a workpiece.

More particularly, the lower strip 12 is provided at each end with a metal bracket 17 which is secured to the lower strip by any suitable bonding or riveting process. Each bracket 17 carries a screw threaded nut 18 which is trunnioned on the bracket and which forms part of the screwed adjuster 14.

Each bracket 17 also has a pair of arms defining a yoke in which is carried a pivot assembly 19 associated with the suction cup 16. The pivot assembly 19 incorporates pivots 20 on a transverse axis to accommodate pivoting associated with different curvature settings of the track member 10. Also, the pivot assembly 19 incorporates a pivot 21 which is provided with a locking nut 22 to allow the attitide of the track member 10 to be adjusted with reference to a workpiece surface. The upper strip 11 carries at each end a bracket 23 on which is trunnioned a screw threaded nut 24 which forms a further part of the screwed adjustcr 14. Oppositelv thrcaded screws 25 a!ld 26 engage rcspectively with the screwed nuts 18 and 24, and the screws 25 and 26 are operable b means of a knurled thumb wheel 27. Thus, rotation of the thumb wheel 27 one way and the other effccts a longitudinal shifting of the strip 11 with respect to the strip 12 by way of the screws 26 and 25 and the hrackets 23 and 17 respectively.

In Figures 3 and 4, it can be seen that the connectors 13 each consist of a pair of flanged elements 28 which are interconnected by means of a screw 29. The flanges of the elements 28 sit in recesses 30 formed at the outer sides of elongate holes 31 formed in the strips 11 and 12 as aforesaid.

The inner ends of the elements 28 engage and clamp a circular washer 32 which is received in a circular opening through the track member 10.

The side edges of the strips 11 and 12 are recessed as can be seen in Figure 4 so that the edge portions of the assembly define longitudinal channels 33 and 34. One longitudinal edge portion of the track member 10 extends into the channel 33 and constitutes a plain track or guideway for co-operation with a grooved guide wheel of a carriage as described herebelow. The opposite edge portion of the track member 10 extends into the channel 34, and this edge portion is in the form of a rack the teeth of which are co-operable with mating teeth of a toothed drive wheel for the said carriage as is also explained herebelow.

With regard to the construction of the connector 15, it will be understood that the arrangement of the parts is as shown in Figure 4 for the connectors 13.

In Figures 5 and 6, a carriage for carrying an instrument or tool in the form of an ultrasonic probe is indicated generally by reference numeral 35. In these Figures, details of the construction of the assembly incorporating the track member 10 have been omitted. The carriage 35 comprises a support plate 36 which carries a longitudinal drive motor 37 for driving the carriage 35 lengthwise of the track member 10 through a toothed drive wheel 38 which engages the rack portion of the track member 10. The plain edge portion of the track member 10 is engaged by grooved guide wheels 39 each of which is mounted on a stub shaft 40 journalled in a bracket 41 secured to the support plate 36 by means of screws 42 of which one is shown in Figure 6.

The carriage 35 is provided with an arm 43 which is extendable and retractable transversely by means of a transverse drive motor 44, a reduction gearing 45, a crank 46 and a connecting link 47. The arm 43 is arranged to run on rollers 48 (see Figure 5) mounted on a roller support member 49 which is secured to the support plate 36. As aforesaid, the tool or instrument of this embodiment is an ultrasonic probe 50 which is arranged in a carrier 51 connected to the arm 43 by means of a parallel linkage 52. An adjusting screw 53 mounted on the upper members of the parallel linkage 52 bears on a compression spring 54 the lower end of which reacts on an adjacent portion of the arm 43. Thus, the adjusting screw 53 and the spring 54 provide an adjustable resilient suspension for the probe 50 whereby the contact pressure between the probe and a workpiece surface can be regulated.

The support plate 36 carries two further brackets 55 each of which carries a reaction wheel 56 for engaging a workpiece surface and for providing a means for balancing the reaction at the interface between the probe 50 and the workpiece surface. Each wheel 56 is vertically adjustable on a sliding rod 57 which is provided with a key 58 to retain the longitudinal alignment of the wheel 56. A locking screw 59 is provided on each bracket 55 for clamping the sliding rods 57 in position.

In operation of the apparatus described above, the longitudinal configuration of the track member 10 is set to the desired curvature (if required) by appropriate manipulation of the thumbwheels 27. Thereafter, the assembly is secured to the workpiece surface by means of the suction cups 16. Since the assembly incorporating the track member 10 retains its configuration conforming with that of the workpiece without the application of externally applied force, the suction cups 16 (or other attachment means) are substantially relieved of stresses other than those associated with the inertia of the carriage 35, the frictional forces between the probe 50 and the workpiece surface, and, possibly, at least part of the weight of the carriage and the track assembly. The motors 37 and 44, in one operational mode envisaged, are controlled by a computer co-ordinating all aspects of the operation of the ultrasonic probe 50 and its investigation pattern.

Within the scope of the appended claims, it is envisaged that an assembly incorporating the flexible track member as described above may be modified by dispensing with the connector 15. In this case, the facility for reversed curvature would not be available.

Also, in an assembly not requiring a reversed curvature facility, only one locating means need be adjustable. It will be appreciated that the ultrasonic probe 50 could be replaced by a wide variety of different instruments or tools, and that for certain applications the transverse arm 43 may also be dispensed with. Also, within the scope of the appended claims, the preferred arrangement of the track member 10 engaged between the upper and lower strips 11 and 12 may be modified for example by dispensing with the track member 10 and incorporating a track or guideway on strip 11 :indoor the strip 12.

WHAT WE CLAIM IS: 1. Apparatus for use in positioning or moving an instrument or tool with reference to the surface of a workpiece, comprising an assembly of at least two mutually parallel elongate flexible elements, first and second means for locating the elements relative to one another with reference to their longitudinal direction, said first and second locating means being mutually longitudinally spaced, at least one of said first and second locating means being operable to permit or effect shifting of one element relative to the other in the longitudinal direction whereby the assembly can be set to and retain a desired curvature, and a flexible track or guideway incorporated in said assembly for co-operating with a carriage for carrying an instrument or tool.

2. Apparatus according to claim 1, wherein the flexible elements are strips arranged face-to-face.

3. Apparatus according to claim 2, wherein the flexible track or guideway is provided on a track member disposed between said strips.

4. Apparatus according to claim 3, wherein the track member is a strip.

5. Apparatus according to any one of the preceding claims, wherein said one of the locating means is operable to effect said shifting of one flexible element relative to the other and comprises mutually engaged screw threaded elements secured to respective ones of the flexible elements.

6. Apparatus according to any one of the preceding claims, wherein each of the first and second locating means is operable to permit or effect shifting of one element relative to the other in the longitudinal direction, and there is provided a third locating means intermediate the first and second locating means, whereby the assembly can be set to and retain mutually different curvatures along the lengths thereof between the first and third and the third and second locating means respectively.

7. Apparatus according to any one of the preceding claims, wherein the assembly is provided with attachment means for attaching the assembly to the surface of a workpiece.

8. Apparatus according to claim 7, wherein the attachment means is connected to the assembly by means adapted to permit adjustment of the attitude of the assembly with reference to a workpiece surface when the attachment means are, in use, attached to said surface.

9. Apparatus according to claim 7 or 8, wherein the attachment means comprises suction cups arranged one adjacent each end of the assembly.

10. Apparatus according to any one of the preceding claims, wherein the~flexible track or guideway comprises a toothed rack for engagement by a drive gear.

11. Apparatus according to any one of the preceding claims, including a carriage for co-operating with the flexible track or guideway, the carriage being adapted to carry an instrument or tool.

12. Apparatus according to claim 11, wherein the carriage is provided with an arm extendible and retractable transversely of the longitudinal direction of the'assembly, said arm being adapted to carry an instrument or tool.

13. Apparatus according to claim 11 or

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Claims

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50 and the workpiece surface. Each wheel 56 is vertically adjustable on a sliding rod 57 which is provided with a key 58 to retain the longitudinal alignment of the wheel 56. A locking screw 59 is provided on each bracket 55 for clamping the sliding rods 57 in position.

In operation of the apparatus described above, the longitudinal configuration of the track member 10 is set to the desired curvature (if required) by appropriate manipulation of the thumbwheels 27. Thereafter, the assembly is secured to the workpiece surface by means of the suction cups 16. Since the assembly incorporating the track member 10 retains its configuration conforming with that of the workpiece without the application of externally applied force, the suction cups 16 (or other attachment means) are substantially relieved of stresses other than those associated with the inertia of the carriage 35, the frictional forces between the probe 50 and the workpiece surface, and, possibly, at least part of the weight of the carriage and the track assembly. The motors 37 and 44, in one operational mode envisaged, are controlled by a computer co-ordinating all aspects of the operation of the ultrasonic probe 50 and its investigation pattern.

Within the scope of the appended claims, it is envisaged that an assembly incorporating the flexible track member as described above may be modified by dispensing with the connector 15. In this case, the facility for reversed curvature would not be available.

Also, in an assembly not requiring a reversed curvature facility, only one locating means need be adjustable. It will be appreciated that the ultrasonic probe 50 could be replaced by a wide variety of different instruments or tools, and that for certain applications the transverse arm 43 may also be dispensed with. Also, within the scope of the appended claims, the preferred arrangement of the track member 10 engaged between the upper and lower strips 11 and 12 may be modified for example by dispensing with the track member 10 and incorporating a track or guideway on strip 11 :indoor the strip 12.

WHAT WE CLAIM IS: 1. Apparatus for use in positioning or moving an instrument or tool with reference to the surface of a workpiece, comprising an assembly of at least two mutually parallel elongate flexible elements, first and second means for locating the elements relative to one another with reference to their longitudinal direction, said first and second locating means being mutually longitudinally spaced, at least one of said first and second locating means being operable to permit or effect shifting of one element relative to the other in the longitudinal direction whereby the assembly can be set to and retain a desired curvature, and a flexible track or guideway incorporated in said assembly for co-operating with a carriage for carrying an instrument or tool.
2. Apparatus according to claim 1, wherein the flexible elements are strips arranged face-to-face.
3. Apparatus according to claim 2, wherein the flexible track or guideway is provided on a track member disposed between said strips.
4. Apparatus according to claim 3, wherein the track member is a strip.
5. Apparatus according to any one of the preceding claims, wherein said one of the locating means is operable to effect said shifting of one flexible element relative to the other and comprises mutually engaged screw threaded elements secured to respective ones of the flexible elements.
6. Apparatus according to any one of the preceding claims, wherein each of the first and second locating means is operable to permit or effect shifting of one element relative to the other in the longitudinal direction, and there is provided a third locating means intermediate the first and second locating means, whereby the assembly can be set to and retain mutually different curvatures along the lengths thereof between the first and third and the third and second locating means respectively.
7. Apparatus according to any one of the preceding claims, wherein the assembly is provided with attachment means for attaching the assembly to the surface of a workpiece.
8. Apparatus according to claim 7, wherein the attachment means is connected to the assembly by means adapted to permit adjustment of the attitude of the assembly with reference to a workpiece surface when the attachment means are, in use, attached to said surface.
9. Apparatus according to claim 7 or 8, wherein the attachment means comprises suction cups arranged one adjacent each end of the assembly.
10. Apparatus according to any one of the preceding claims, wherein the~flexible track or guideway comprises a toothed rack for engagement by a drive gear.
11. Apparatus according to any one of the preceding claims, including a carriage for co-operating with the flexible track or guideway, the carriage being adapted to carry an instrument or tool.
12. Apparatus according to claim 11, wherein the carriage is provided with an arm extendible and retractable transversely of the longitudinal direction of the'assembly, said arm being adapted to carry an instrument or tool.
13. Apparatus according to claim 11 or

12, including motor means on the carriage and operable to drive the carriage along the track or guideway.
14. Apparatus according to claim 12 or 13, including motor means on the carriage and operable to extend and retract the arm.
15. Apparatus for use in positioning or moving an instrument or tool with reference to the surface of a workpiece, substantially as hereinbefore described with reference to and as shown in Figures 1,2,3 and 4 of the accompanying drawings.
16. Apparatus for use in positioning or moving an instrument or tool with reference to the surface of a workpiece, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.