GB1597408A

GB1597408A - Load measurement apparatus

Info

Publication number: GB1597408A
Application number: GB1595278A
Authority: GB
Original assignee: PRECISION ENG CO READING Ltd
Current assignee: PRECISION ENG CO READING Ltd
Priority date: 1978-04-21
Filing date: 1978-04-21
Publication date: 1981-09-09

Description

(54) IMPROVEMENTS IN OR RELATING TO LOAD MEASUREMENT APPARATUS (71) We, PRECISION ENGINEERING Co.

(READING) LIMITED, a British Company of Meadow Road, Reading RG1 8LB, Berkshire, England, 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 load measurement, including base structure; load support structure which is supported by means which interact with the base structure so that it is guided for movement relative to the base structure; a resilient link which is coupled at one end to the base structure and at another end to the load support structure; and load indicator means comprising a spindle which carries an indicator arm and which is journal in a journal support which is carried by one of the base structure and the load support structure, the spindle being adapted to be rotated as the load support structure moves relative to the base structure, when the apparatus is in use to weigh a load, the indicator arm, which rotates with rotation of the spindle, being arranged to sweep an indicator scale when so rotated, the indicator scale being mounted in an externally visible location. Such apparatus is referred to elsewhere in this Specification as "load measurement apparatus of the type described".

Both the base structure and the load support structure of the form of load measure- ment apparatus of the type described that we prefer to use comprise elongate channel section members which are orientated one relative to the other so that the side walls of one of them project from the base of that one into the recess formed between the side walls of the other, there being grooves formed in each side wall which serve as tracks for ball bearings and the grooved parts of each side wall of the base structure channel section member cooperating with the grooved parts of the adjacent side wall of the load structure channel section member to compose the cage for the ball bearings so that the two channel section members and the ball bearings together constitute a rolling bearing assembly.

The Complete Specifications ffled in connection with our co-pending Patent Applications Nos. 23639/75 Serial No. 1 554 556 and 4780/77 Serial No. 1 595 583 describe and claim various forms of load measurement apparatus of the type described which incorporate such a rolling bearing assembly.

Another known form of load measurement apparatus of the type described, which has its base structure incorporated in a pedestal which is designed to stand upon a horizontal support surface, includes a hollow non-load bearing shroud which is carried by the load support structure, which includes the indicator scale and upon which the load bearing pan rests when the apparatus is in use to weigh a load.

An object of this invention is to so arrange the base structure and load support structure of the form of load measurement apparatus of the type described that has its base structure incorporated in a pedestal and which includes such a hollow non-load bearing shroud which is carried by the load support structure, that they may co-operate together to constitute the form of rolling bearing assembly that we prefer to use.

The problem is that either the mass of the load support structure and a load being weighed exerts an undesirably large leverage on the base structure or the ball bearings are not free to roll if we use one of the arangements of rolling bearing assembly that have been proposed so far.

According to this invention we provide apparatus for load measurement including base structure which forms at least one straight guideway and which is incorporated in a pedestal which is designed to stand upon a horizontal support surface; load support structure which is supported by means which interact with the guideway or guideways so that it is guided by the guideway or guideways for rectilinear movement relative to the base structure; a resilient link which is coupled at one end to the base structure and at another end to the load support structure; a hollow non-load bearing shroud which is carried by the load support structure so that the interengaged parts of the base structure and the load support structure are located within its interior; and load indicator means comprising a spindle which carries an indicator arm and which is journaled in a journal support which is carired by the load support structure, the spindle carrying a pinion which meshes with an elongate rack which is adapted to be supported in fixed relationship realtive to the base structure, when the apparatus is in use to weigh a load, so that the spindle is rotated by the interengagement of the rack and pinion as the load support structure moves relative to the base structure, the indicator arm, which rotates with rotation of the spindle, being arranged to sweep an indicator scale when so rotated, the indicator scale being marked upon an externally visible surface of the shroud, and the journal support being carried by the load support structure by means of a cantilever arrangement which extends from the load support structure to the other side of the base structure so that the base structure extends between the journal support and the load support structure.

Preferably the base structure is apertured so that the cantilever arrangement extends through it.

Adjustment means may be provided on an externally accessible part of the pedestal for adjusting the position of the rack relative to the base structure. The apparatus may include rack support means from which the rack depends and which are connected to the adjustment means, the rack support means including a rod portion which is a sliding fit within a correspondingly shaped aperture formed in an arm which projects from the base structure to said other side of the base structure, the aperture being orientated so as to guide the rod portion for sliding movement along a path which extends substantially parallel to the or each said guideway. The rack support means may include an arm which extends laterally from the rod portion and from which the rack depends, the laterally extending arm extending above the spindle so that the spindle extends between the rack and the rod portion.Conveniently each of the rod portion and the correspondingly shaped aperture is rectangular in cross-section. Conveniently that part of the rod portion that is a sliding fit within the correspondinvly shaped aperture extends between the laterally extending arm and a resilient finger which serves as a stop which cooperates with the perimeter of the correspondingly shaped aperture to limit sliding movement of the rod portion within the corespondingly shaped aperture in the direction which moves the laterally extending arm away from the correspondingly shaped aperture, and which can be deflected from its natural condition so that it can be passed through the correspondingly shaped aperture to allow withdrawal of the rod portion from the correspondingly shaped aperture.

Conveniently the or each guideway is a track for rolling bearing elements and a suitable cage arrangement is provided to ensure that the rolling bearing elements remain on the respective track. Preferably there are two such guideways which are formed by the base structure and one of the base structure and the load support structure, preferably the former, is arranged so that it forms an elongate recess into which projects part of the other of the base structure and the load support structure, the pair of guideways and said means which interact with the guideways to support and guide the load support structure relative to the base structure being within the recess.

Each of the guideways formed in the base structure may comprise a groove which extends along the total length of the base structure. Preferably the rolling bearing elements comprise ball bearings and a positive stop surface is formed adjacent the upper end of each groove in the base structure, each stop surface extending substantially normal to the rolling surface for the ball bearings that is formed by the respective groove and being adapted so that, when a ball bearing is rolled into contact with it, it abuts the ball bearing at a location on the spherical surface of that ball bearing which is spaced angularly by more than 45" from the point of rolling contact between that ball bearing and its rolling surface.Conveniently there are two grooves which are formed one in each of the outermost side surfaces of the load support structure and extending along substantially the total length of the load support structure, each groove forming a rolling surface for the ball bearings and having configurations formed at spaced intervals along its length, each rolling bearing being located between a respective spaced pair of the configurations and the lower configuration of each such spaced pair of configurations forming a positive stop surface, each such stop surface extending substantially normal to the rolling surface for the ball bearings that is formed by the respective groove and being adapted so that, when a ball bearing is rolled into contact with it, it abuts that ball bearing at a location on the spherical surface of that ball bearing which is spaced angularly by more than 45" from the point of rolling contact between that ball bearing and its rolling surface. Conveniently those parts of the base structure and the load support structure that receive rolling bearing elements co-operate together to compose the cage for the rolling bearing elements of the resultant rolling bearing assembly.

The load support structure may include an elongate channel section member, the grooves being formed by the side walls of the channel. Where the elongate recess is formed in the base structure, the base structure may comprise a channel section member, the grooves being formed at the end of each of the side walls of the channel that is remote from the base of the channel.

The base structure may be mounted upon the pedestal so that the path of rectilinear movement of the load support structure relative to the base structure is at an acute angle to the support surface when the pedestal is stood upon that support surface, the angle between the path of rectilinear movement of the load support structure and the vertical being somewhat less than the angle between the path of rectilinear movement of the load support structure and the support surface.

One embodiment of this invention will be described now by way of example with reference to the acompanying drawings of which: Figure 1 is a perspective view of one form of kitchen scales in which this invention is embodied, part of the face of the body being cut away to show the internal mechanism; and Figure 2 is a plan view of the mechanism of the kitchen scales shown in Figure 1.

Referring to the drawings, the kitchen scales comprise a spring balance assembly 10 which is supported by a pedestal 11 and which is located within the interior of a hollow canopy like shroud 12, each of the pedestal 11 and the shroud 12 being a moulding of plastics material. For the sake of convenience the following description of the scales is written on the assumption that the scales as described are standing on a horizontal work surface.

The spring balance assembly 10 includes base structure which is supported by the pedestal 11, and movable load support structure which carries the shroud 12. The upper surface of the shroud 12 is adapted to support and locate the load pan 13 of the scales.

The main component of the base structure is a channel section component 14 which has a base 15 and side walls 16.

Figure 1 shows that the base 15 is at an acute angle with the horizontal. Conveniently the angle between the base 15 and the horizontal is of the order of 80". Figure 2 shows that each side wall 16 of the channel section base structure component 14 has an elongate groove formed in the inner surface by an arcuate portion 17 at its end remote from the base 15. An inwardly directed local distortion 18 is formed in each arcuate portion 17 at the top of the component 14.

The main component of the load support structure is a channel section component 19 having a base 20 and a pair of side walls 21. The overall length of the channel section load support structure component 19 is substantially the same as that of channel section base structure component 14. Each side wall 21 of the component 19 has an elongate groove formed in its outer surface by an arcuate portion 22, the groove extending from end to end of the respective side wall 21 parallel to the base 19. Two pairs of longitudinally spaced outwardly directed local distortions 23 are formed in each side wall 21. Each distortion 23 may be in the region of the junction between the arcuate portion 22 of that side wall 21 and the planar portion that connects that arcuate portion 22 to the base 20 of that component 19, or, as is shown in Figure 2, may be adjacent the outer edge of the arcuate portion 22.The distance between the distortions 23 of each pair is substantially the same. One of the pairs of distortions 23 in each side wall 21 is located in the lower quarter of that side wall 21 and the other pair of distortions 23 in that side wall 21 is located substantially at the centre of the upper half of that side wall 21.

The distance between the side walls 16 of the base support structure channel section component 14 is greater than the distance between the side walls 21 of the load support structure channel section component 19. The side walls 21 project into the elongate recess that is formed by the component 14 between the side walls 16. The elongate grooves formed at the end of each side wall 16 and those portions of the elongate grooves in the side walls 21 that extend between the two distortions 23 of each pair co-operate together as straight tracks for four ball bearings 24, each ball bearing 24 being located between the two distortions 23 of a respective one of the four pairs of distortions 23 and being engaged by the sides of the arcuate portion 17 of the channel section base structure component 14 and by the sides and ends of the arcuate portions 22 of the component 19.Moreover the two channel section components 14 and 19 are locked together by the ball bearings 24. Hence the load support structure is supported by the rolling bearing assembly for rectilinear movement along a path which is substantially parallel to the base 15 of the channel section base structure component 14.

Each distortion 18, 23 is formed, for example by punching or piercing, so that it provides a positive stop surface for the adjacent ball bearing 24 which extends as near as is practical to the normal to the straight rolling surface that is formed for that ball bearing 24 by the respective arcuate portion 17, 22. Hence the distortions 18 and 23 serve to limit upwards rectilinear movement of the load support structure. The inwardly directed distortions 18 formed at the top of the channel section base structure component 14 retain the upper ball bearings 24 in engagement with their tracks.When each upper ball bearing 24 is rolled into contact with the respective inwardly directed local distortion 18, that distortion 18 abuts that ball bearing 24 at a point on the spherical surface of that ball bearing 24 which is spaced angularly from the point of rolling contact between that spherical surface and its track surface formed by the respective side walls 16 by more than 45" and as near to 90" as is practical so as to minimise the likelihood that that ball bearing 24 and the stop surface provided by the respective local distortion 19 interact with one another in a manner of a wedge and ramp. The upper one of each of the two upper pairs of outwardly directed local distortions 23 is above the top of the base component 14 when the apparatus is unladen.The lower one of each of the pairs of inwardly directed local distortions 23 co-operates with the adjacent ball bearing 24 to provide a positive stop surface for that ball bearing 24 in a manner similar to that with which the inwardly directed local distortion 18 provides such a stop surface as is described above.

A coil spring 25 (see Figure 2) is anchored at one end to a tongue 26 which projects inwardly from the base 15 of the channel section base structure component 14 and is connected at its other end to a torque 27 which projects inwardly from the base 20 of the channel section load support structure component 19.

A U-shaped sheet metal component 28 is mounted by its ends in the base 20 of the channel section load support structure component 19. Two vertical slots 29 are formed in the base 15 of the channel section load support structure component 14.

Each arm 30 of the component 28 extends through a respective one of the slots 29 so that the base 15 extends between the base 20 and the base 31 of the U-shaped component 28. Hence the arms 30 provide a cantilever support from the load support structure for the base 31. A pinion housing 32 is mounted within the base 31 of the U-shaped component 28. A pinion 33 is mounted coaxially upon a spindle 34 which is journaled within the housing 32 so that it projects from both ends of that housing 32. The pinion housing 32 is similar in construction to the pinion housing 74 of the scales described in the Complete Specification of our co-pending Patent Application No. 23639/75 Serial No. 1 554 556 and it is mounted in the base 31 of the component 28 in a similar manner to the manner of installation of the pinion housing 74 described in detail in that Complete Specification.

An arm 35 is fixed at one end to the surface of the base 15 of the channel section base structure component 14 that is remote from the channel section load structure component 19 and projects from that face substantially normal to that face. The arm 35 has a hollow boss 36 at its other end. The boss 36 forms an aperture which has a rectangular cross-section, the longi- tudinal axis of the aperture being substantially parallel to the base 15 of the channel section base structure component 14.

A rectangular rod portion 37 is a sliding fit within the aperture formed by the hollow boss 36. A horizontal arm 38 extends laterally from the upper end of the rod portion 37 above and across the pinion housing 32. An adjuster bolt 39 has its head trapped in the lower end of the rectangular rod portion 37. The threaded shank of the adjuster bolt 39 depends from the rectangu lar rod portion 37 and is screwed into an adjuster nut 40 which is held captive within the pedestal 11.

A rack member 41 is hinged to the horizontal arm 38 at the end of that arm remote from the rectangular rod portion 37.

The rack member 41 is similar to that described in detail in the Complete Specification filed in connection with our copending Patent Application No. 23639/75 Serial No.

1 554556 and depends from the horizontal arm 38 with its teeth in mesh with the pinion 33.

The spindle 34 carries a radially extending pointer 42 between a transparent front part 43 of the shroud 12 and the base 31 of the component 28. An indicator scale 44 is laid upon the outer surface of the base 31 and is fitted at its periphery into the shroud 12 so that the indicia thereon are swept by the pointer 42 with rotation of the spindle 34.

When the apparatus is unladen each ball bearing 24 rests on the lower distortion 23 of the respective pair. The two upper ball bearings 24 are below and spaced from the respective inwardly-directed distortion 18. The load support structure hangs from the coil spring 25 which is suspended from the base structure and which is free to assume its equilibrium condition.

When a load to be weighed is placed in the load pan 13, the load support structure is deflected against the action of the coil spring 25. The balls 24 roll in their tracks as the movable load support structure travels downwards with the load to be weighed. Hence the lower distortion 23 of each pair separates from the adjacent ball bearing 24. The rolling bearing assembly formed by the two channel section components 14 and 19 ensures that movement of the load support structure is rectilinear.

Such rectilinear movement of the load support structure includes like rectilinear movement of the U-shaped component 28 that carries the pinion housing 32. Hence the pinion 33 is moved relative to the rack member 41 which is relatively static and the resultant rotary movement of the spindle 34, due to the interaction of the rack teeth and the pinion 33, moves the pointer 42 to a position which is indicative of the weight of the load in the load pan 13, the load being read from the scale 44 in the usual way.

When the load is removed from the scales, the spring 25 contracts and the movable load support structure is urged upwards. As is well known, contraction of the spring 25 does not stop at the instant equilibrium conditions are re-established and the lower end of the spring 25 is liable to oscillate about the point it adopts when such equilibrium conditions exist until the system stabilises. If the initial contraction of the spring 25 is excessive, upwards movement of the load support structure may be stopped by abutment of each of the inwardly-directed distortions and by the respective one of the upper pair of ball bearings 24 which will have been abutted and borne upwards by the respective lower ones of the upper pairs of distortion 23.

The pointer 42 can be zeroised when the load pan 13 is empty by manipulation of the adjuster nut 40 which is partially exposed below the shroud 12 and which thereby is readily accessible.

Use of a cantilever arrangement to support the pinion housing of the apparatus from the channel section load support structure component 19 enables the component 19 to be located substantially below the centre of the load pan 13 and for the side walls of both the channel section components 14 and 19 to be relatively short.

Central location of the movable channel section load- structure support component 19 minimises the loads that tend to separate it from the channel section base structure component 14 and minimising the length of the side walls of those two components reduces the need for them to be reinforced.

The rod portion 37 of the rack member support arrangement has an aperture 45 formed in it below the hollow boss 36 and above the head of the adjuster bolt 39. A resilient finger 46 projects upwardly and outwardly from the lower edge of the aperture 45. The upper end of the resilient finger 46 serves as a stop which limits upward movement of the rod portion 37 by abutment with the lower edge of the hollow boss 36. The upper end of the finger 46 may be deflected against its resilience, inwardly relative tothe rod portion 37, to enable the rod portion 37 to be withdrawn upwardly through the hollow boss 36. It will be recognised that the finger 46 is deflected by the hollow boss 36 whilst the rod portion 37 is inserted downwardly through the aperture formed by the hollow boss 36 during assembly of the apparatus.

WHAT WE CLAIM IS: 1. Apparatus for load measurement including base structure which forms at least one straight guideway and which is incorporated in a pedestal which is designed to stand upon a horizontal support surface; load support structure which is supported by means which interact with the guideway or guideways so that it is guided by the guideway or guideways for rectilinear movement relative to the base structure; a resilient link which is coupled at one end to the base structure and at another end to the load support structure; a hollow non-load bearing shroud which is carried by the load support structure so that the interengaged parts of the base structure and the load support structure are located within its interior; and load indicator means comprising a spindle which carries an indicator arm and which is journaled in a journal support which is carried by the load support structure, the spindle carrying a pinion which meshes with an elongate rack which is adapted to be supported in fixed relationship relative to the base structure, when the apparatus is in use to weigh a load, so that the spindle is rotated by the interengagement of the rack and pinion as the load support structure moves relative to the base structure, the indicator arm, which rotates with rotation of the spindle, being arranged to sweep an indicator scale when so rotated, the indicator scale being marked upon an externally visible surface of the shroud, and the journal support being carried by the load support structure by means of a cantilever arrangement which extends from the load support structure to the other side of the base structure so that the base structure extends between the journal support and the load support structure.

2. Apparatus according to Claim 1, wherein the base structure is apertured so that the cantilever arrangement extends through it.

3. Apparatus according to Claim 1 or Claim 2, wherein adjustment means are provided on an externally accessible part of the pedestal for adjusting the position of

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. as the movable load support structure travels downwards with the load to be weighed. Hence the lower distortion 23 of each pair separates from the adjacent ball bearing 24. The rolling bearing assembly formed by the two channel section components 14 and 19 ensures that movement of the load support structure is rectilinear. Such rectilinear movement of the load support structure includes like rectilinear movement of the U-shaped component 28 that carries the pinion housing 32. Hence the pinion 33 is moved relative to the rack member 41 which is relatively static and the resultant rotary movement of the spindle 34, due to the interaction of the rack teeth and the pinion 33, moves the pointer 42 to a position which is indicative of the weight of the load in the load pan 13, the load being read from the scale 44 in the usual way. When the load is removed from the scales, the spring 25 contracts and the movable load support structure is urged upwards. As is well known, contraction of the spring 25 does not stop at the instant equilibrium conditions are re-established and the lower end of the spring 25 is liable to oscillate about the point it adopts when such equilibrium conditions exist until the system stabilises. If the initial contraction of the spring 25 is excessive, upwards movement of the load support structure may be stopped by abutment of each of the inwardly-directed distortions and by the respective one of the upper pair of ball bearings 24 which will have been abutted and borne upwards by the respective lower ones of the upper pairs of distortion 23. The pointer 42 can be zeroised when the load pan 13 is empty by manipulation of the adjuster nut 40 which is partially exposed below the shroud 12 and which thereby is readily accessible. Use of a cantilever arrangement to support the pinion housing of the apparatus from the channel section load support structure component 19 enables the component 19 to be located substantially below the centre of the load pan 13 and for the side walls of both the channel section components 14 and 19 to be relatively short. Central location of the movable channel section load- structure support component 19 minimises the loads that tend to separate it from the channel section base structure component 14 and minimising the length of the side walls of those two components reduces the need for them to be reinforced. The rod portion 37 of the rack member support arrangement has an aperture 45 formed in it below the hollow boss 36 and above the head of the adjuster bolt 39. A resilient finger 46 projects upwardly and outwardly from the lower edge of the aperture 45. The upper end of the resilient finger 46 serves as a stop which limits upward movement of the rod portion 37 by abutment with the lower edge of the hollow boss 36. The upper end of the finger 46 may be deflected against its resilience, inwardly relative tothe rod portion 37, to enable the rod portion 37 to be withdrawn upwardly through the hollow boss 36. It will be recognised that the finger 46 is deflected by the hollow boss 36 whilst the rod portion 37 is inserted downwardly through the aperture formed by the hollow boss 36 during assembly of the apparatus. WHAT WE CLAIM IS:

1. Apparatus for load measurement including base structure which forms at least one straight guideway and which is incorporated in a pedestal which is designed to stand upon a horizontal support surface; load support structure which is supported by means which interact with the guideway or guideways so that it is guided by the guideway or guideways for rectilinear movement relative to the base structure; a resilient link which is coupled at one end to the base structure and at another end to the load support structure; a hollow non-load bearing shroud which is carried by the load support structure so that the interengaged parts of the base structure and the load support structure are located within its interior; and load indicator means comprising a spindle which carries an indicator arm and which is journaled in a journal support which is carried by the load support structure, the spindle carrying a pinion which meshes with an elongate rack which is adapted to be supported in fixed relationship relative to the base structure, when the apparatus is in use to weigh a load, so that the spindle is rotated by the interengagement of the rack and pinion as the load support structure moves relative to the base structure, the indicator arm, which rotates with rotation of the spindle, being arranged to sweep an indicator scale when so rotated, the indicator scale being marked upon an externally visible surface of the shroud, and the journal support being carried by the load support structure by means of a cantilever arrangement which extends from the load support structure to the other side of the base structure so that the base structure extends between the journal support and the load support structure.

the rack relative to the base structure.

4. Apparatus according to Claim 3, wherein the apparatus includes rack support means from which the rack depends and which are connected to the adjustment means, the rack support means including a rod portion which is sliding fit within a correspondingly shaped aperture formed in an arm which projects from the base structure to said other side of the base structure, the aperture being orientated so as to guide the rod portion for sliding movement along a path which extends substantially parallel to the or each said guideway.

5. Apparatus according to Claim 4, wherein the rack support means include an arm which extends laterally from the rod portion and from which the rack depends, the laterally extending arm extending above the spindle so that the spindle extends between the rack and tne rod portion.

6. Apparatus according to Claim 4 or Claim 5, wherein each of the rod portion and the correspondingly shaped aperture is rectangular in cross-section.

7. Apparatus according to any one of Claims 4 to 6, wherein that part of the rod portion that is a sliding fit within the correspondingly shaped aperture extends between the laterally extending arm and a resilent finger which serves as a stop which cooperates with the perimeter of the correspondingly shaped aperture to limit sliding movement of the rod portion within the correspondingly shaped aperture in the direction which moves the laterally extending arm away from the correspondingly shaped aperture, and which can be deflected from its natural condition so that it can be passed through the correspondingly shaped aperture to allow withdrawal of the rod portion from the correspondingly shaped aperture.

8. Apparatus according to any one of Claims 1 to 7, wherein the or each guideway is a track for rolling bearing elements and a suitable cage arrangement is provided to ensure that the rolling bearing elements remain on the respective track.

9. Apparatus according to Claim 8, wherein there are two such guideways which are formed by the base structure and one of the base structure and the load support structure is arranged so that it forms an elongate recess into which projects part of the other of the base structure and the load support structure, the pair of guideways and said means which interact with the guideways to support and guide the load support structure relative to the base structure being within the recess.

10. Apparatus according to Claim 9, wherein the recess is formed by the base structure.

11. Apparatus according to Claim 9 or Claim 10, wherein each of the guideways formed in the base structure comprises a groove which extends along the total length of the base structure.

12. Apparatus according to Claim 11, wherein the rolling bearing elements comprise'ball bearings and a positive stop surface is formed adjacent the upper end of each groove in the base structure, each stop surface extending substantially normal to the rolling surface for the ball bearings that is formed by the respective groove and being adapted so that, when a ball bearing is rolled into contact with it, it abuts the ball bearing at a location on the spherical surface of the ball bearing which is spaced angularly by more than 45" from the point of rolling contact between that ball bearing and its rolling surface.

13. Apparatus according to Claim 12, wherein there are two grooves which are formed one in each of the outermost side surfaces of the bad support structure and extending along substantially the total length of the load support structure, each groove forming a rolling surface for the ball bearings and having configurations formed at spaced intervals along its length, each rolling bearing being located between a respective spaced pair of the configurations and the lower configuration of each such spaced pair of configurations forming a positive stop surface, each such stop surface extending substantially normal to the rolling surface for the ball bearings that is formed by the respective groove and being adapted so that, when a ball bearing is rolled into contact with it, it abuts that ball bearing at a location on the spherical surface of that ball bearing which is spaced angularly by more than 45" from the point of rolling contact between that ball bearing and its rolling surface.

14. Apparatus according to any one of Claims 8 to 13, wherein those parts of the base structure land the load support structure that receive rolling bearing elements co-operate together to compose the cage for the rolling bearing elements of the resultant rolling bearing assembly.

15. Apparatus according to Claim 13 or Claim 14 when appended to Claim 13, wherein the load support structure includes an elongate channel section member, the grooves being formed by the side walls of the channel.

16. Apparatus according to any one of Claims 11 to 13 and 15 when appended to Cllaim 10, or Claim 14 when appended to Claims 10 and 11, wherein the base structure comprises a channel section member, the grooves being formed at the end of each of the side walls of the channel that is remote from the base of the channel.

17. Apparatus according to any one of Claims 1 to 16, wherein the base structure is mounted upon the pedestal so that the path of rectilinear movement of the load support structure relative to the base structure is at an acute angle to the support surface when the pedestal is stood upon that support surface the angle between the path of rectilinear movement of the load support structure and the vertical being somewhat less than the langle between the path of rectilinear movement of the load support structure and the support surface.

18. Apparatus for load measurement substantially as described hereinbefore with reference to and as shown in the accompanying drawings.