GB2132286A - Two assemblies relatively movable by means of rolling elements - Google Patents

Two assemblies relatively movable by means of rolling elements Download PDF

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Publication number
GB2132286A
GB2132286A GB08330139A GB8330139A GB2132286A GB 2132286 A GB2132286 A GB 2132286A GB 08330139 A GB08330139 A GB 08330139A GB 8330139 A GB8330139 A GB 8330139A GB 2132286 A GB2132286 A GB 2132286A
Authority
GB
United Kingdom
Prior art keywords
guide rail
limbs
screw
another
assembly
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08330139A
Other versions
GB8330139D0 (en
GB2132286B (en
Inventor
Rudiger Neumann
Walter Reith
Lothar Walter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SKF GmbH
Original Assignee
SKF Kugellagerfabriken GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SKF Kugellagerfabriken GmbH filed Critical SKF Kugellagerfabriken GmbH
Publication of GB8330139D0 publication Critical patent/GB8330139D0/en
Publication of GB2132286A publication Critical patent/GB2132286A/en
Application granted granted Critical
Publication of GB2132286B publication Critical patent/GB2132286B/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C29/00—Bearings for parts moving only linearly
    • F16C29/12—Arrangements for adjusting play
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G3/00—Ambulance aspects of vehicles; Vehicles with special provisions for transporting patients or disabled persons, or their personal conveyances, e.g. for facilitating access of, or for loading, wheelchairs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C29/00—Bearings for parts moving only linearly
    • F16C29/04—Ball or roller bearings
    • F16C29/048—Ball or roller bearings with thin walled races, e.g. tracks of sheet metal

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Veterinary Medicine (AREA)
  • Transmission Devices (AREA)
  • Bearings For Parts Moving Linearly (AREA)

Abstract

Two assemblies 10, 11 are moveable relative to one another by two rows of rolling elements 22. Each assembly 10, 11 has tracks 20, 21 accommodating the elements 22. A first assembly 10 includes a resiliently flexible guide rail 14 comprising a base 16 and two limbs 18 providing the tracks 20. Rotation of an elongate screw-threaded member 24 adjusts the play between the tracks 20, 21 and the rolling elements 22. The screw-threaded member 24 engages the support 12 for the rail 14 of the first assembly 10 and extends in a direction which lies between the limbs 18 of the guide rail 14. <IMAGE>

Description

SPECIFICATION Two assemblies relatively movable by means of rolling elements This invention concerns first and second assemblies arranged for movement with respect to one another by two rows of rolling elements.
Patent specifications U.S. 2261504 discloses an adjustable supporting device in which first and second assemblies are arranged for longitudinal movement with respect to one another by two rows of rolling elements. Each assembly has two tracks, one track accommodating one row and the other track accommodating the other row of the rolling elements.
The first assembly includes a resiliently flexible open channel section guide rail which in crosssection comprises a base, which is secured to a support of the first assembly, and two limbs extending towards the second assembly. The two limbs provide the tracks of the first assembly.
An elongate screw-threaded member is provided for adjusting the play between the tracks and the rolling elements, rotation of the screwthreaded member causing the limbs of the guide rail to be urged towards or away from one another.
The guide rail is said to be made of sheet metal, which has the advantages of being relatively cheap and allows articles to be made which are light in weight. However, the guide rails tend to be distorted when hardening the tracks for the rolling elements. The result of this is that of too much play between the tracks and the rolling elements.
In U.S. 2261504, the elongate screw-threaded member is a bolt which extends through both of the limbs of the guide rail, a nut being screwed on to the end. This means that the limbs have to extend from the base far enough to accommodate a bolt passing through as well as tracks for the rolling elements. Also the limbs have to be provided with aligned holes for the bolt. These mean that this known construction does not lend itself to being compact and cheap to produce.
The invention provides first and second assemblies arranged for movement with respect to one another by two rows of rolling elements, each assembly having two tracks, one track accommodating one row and the other track accommodating the other row of the rolling elements, the first assembly including a resiliently flexible guide rail which in cross-section comprises a base, which is secured to a support of the first assembly, and two limbs extending towards the second assembly, the two limbs providing the tracks of the first assembly, and an elongate screw-threaded member which is provided for adjusting the play between the tracks and the rolling elements, rotation of the screw-threaded member causing the limbs of the guide rail to be urged towards or away from one another, wherein the screw-threaded member engages the support of the first assembly and extends in a direction which lies between the limbs of the guide rail.
With this construction, the limbs of the guide rail only have to extend from the base a distance sufficient to provide the race tracks, and only a single opening, in the base of the guide rail, is necessary for the screw-threaded member. Thus the construction according to the invention can be made relatively cheaply and be compact. This is particularly important in, for example, a telescopic unit which incorporates the invention and is used for stretcher supports for ambulances.
In a construction in which the rolling elements are disposed to roll along the surfaces of the limbs of the guide rail facing towards one another, the base of the guide rail may curve into between the limbs of the rail, and the screw-threaded member may engage the curved base such that, when the screw-threaded member is rotated in one direction, clockwise or anti-clockwise, the base of the guide rail is flattened which causes the limbs of the guide rail to be urged towards one another.
Preferably, the screw-threaded member engages the crown of the curvature of the base.
In a construction in which the rolling elements are disposed to roll along the surfaces of the limbs of the guide rail facing away from one another, the screw-threaded member may extend between the limbs of the guide rail, and an adjusting element, having converging surfaces engaging the surfaces of the limbs of the guide rail facing towards one another, may be screwed on to the screwthreaded member, all such that when the screwthreaded member is rotated in one direction, clockwise or anti-clockwise, the adjusting element moves in one direction lengthwise of the screwthreaded member and urges the limbs of the guide rail away from one another. Preferably the adjusting element is a truncated cone.
Each assembly may include a guide rail providing two tracks accommodating the rows of the rolling elements, and each guide rail may be symmetrical in cross-section.
Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, of which: Figure 1 is a cross-section of two assemblies according to the invention in which the limbs of a guide rail can be urged towards one another by means of a screw-threaded member engaging the curved base of the rail; Figure 2 is a cross-section of two assemblies according to the invention in which the limbs of a guide rail can be urged away from one another by means of a screw-threaded member and an adjusting element engaging the limbs; and Figure 3 is a cross-section of two assemblies according to the invention in which the limbs of a guide rail can be urged towards one another by means of a screw-threaded member engaging the curved base of the rail.
The pairs of assemblies illustrated in Figures 1 to 3 can, for example, be incorporated in telescopic guides in stretcher supports for ambulances.
Figure 1 shows first and second assemblies 10 and 11, each assembly including a support 12, 13 and a longitudinally extending resiliently flexible guide-rail 14, 1 5. Each guide rail 14, 15 is of open channel section and is made from sheet metal. In cross-section each guide rail 14, 1 5 is symmetrical and comprises a base 1 6, 1 7 which is secured to the corresponding support 1 2, 1 3 and two limbs 1 8, 1 9 which extend towards the other assembly. A part of each limb 18, 19 of each guide rail 14, 15 is curved in cross-section to provide longitudinally extending race track grooves 20, 21 for two rows of balls 22.One row of balls 22 is disposed to roll along the race track groove 20 of one limb 18 of the rail 14 and along the race track groove 21 of one limb 1 9 of the rail 15, and the other row of balls is disposed to roll along the race track groove 20 of the other limb 18 of the rail 14 and along the race track 21 of the other limb 1 9 of the rail 1 5. The surfaces of the race track grooves 20 of the limbs 1 8 of the rail 14 face towards each other, and the surfaces of the race track grooves 21 of the limbs 1 9 of the rail 1 5 face away from each other. Both rows of balls 22 are guided by a single common sheet metal cage 23. This construction of the two assemblies 10 and 11 allows longitudinal movement (perpendicular to the plane of the drawing) of one assembly with respect to the other.
The base 16 of the guide rail 14 is curved in cross-section, it curving inwardly between the two limbs 1 9 of the rail. An elongate screw-threaded member 24, such as a bolt, extends in a direction which lies between the limbs 1 8, 1 9 of the guide rails 14, 15. It has a head lying on the side of the base 1 6 of the rail 14 opposite to the support 12 and a shank extending through an aperture 25 in the base and into a correspondingly screwthreaded bore 26 in the support 12. The head of the bolt 24 engages the crown of the curvature of the base 1 6 of the guide rail 14. Rotation of the bolt 24 into the bore 26 (clockwise for a conventional right hand thread) will cause the base 1 6 to flatten and will thus urge the limbs 18 towards one another thus reducing play between the race track grooves 20 and 21 and the balls 22.
The reverse is true -- rotating the bolt 24 anticlockwise out of the bore 26 will increase the play.
By using a fine thread pitch for the bolt 24 and bore 26, fine adjustment of the play is possible.
Figure 2 shows first and second assemblies 30 and 31, each assembly including a support 32, 33 and a longitudinally extending resiliently flexible guide-rail 34, 35. Each guide rail 34, 35 is of open channel section and is made from sheet metal. In cross-section each guide rail 34, 35 is symmetrical and comprises a base 36, 37 which is secured to the corresponding support 32, 33 and two limbs 38, 39 which extend towards the other assembly. A part of each limb 38, 39 of each guide rail 34, 35 is curved in cross-section to provide longitudinally extending race track grooves 40, 41 for two rows of balls 42.One row of balls 42 is disposed to roll along the race track groove 40 of one limb 38 of the rail 34 and along the race track groove 41 of one limb 39 of the rail 35, and the other row of balls is disposed to roll along the race track groove 40 of the other limb 38 of the rail 34 and along the race track groove 41 of the other limb 39 of the rail 35. The surfaces of the race track grooves 40 of the limbs 38 of the rail 34 face away from each other, and the surfaces of the race track grooves 41 of the limbs 39 of the rail 35 face towards each other. Both rows of balls 42 are guided by a single common sheet metal cage 43. This construction of the two assemblies 30 and 31 allows longitudinal movement (perpendicular to the plane of the drawing) of one assembly with respect to the other.
An elongate screw-threaded member 44 such as a bolt with a socket head extends in a direction which lies between the limbs 38, 39 of the guide rails 34, 35. It has a head lying in a recess in the support 32 and a shank extending with clearance through a bore 45 in the support and through an aperture 46 in the base 36 of the guide rail 34. An adjusting element 47 having converging surfaces, such as a truncated cone, is screwed onto the shank of the bolt 44, the surfaces converging with one another in the direction towards the support 32. The cone 47 bears against the curved surfaces of the limbs 38 of the guide rail 34 facing towards one another.Rotation of the bolt 44 (clockwise for a conventional right hand thread) causes the cone 47 to be moved lengthwise of the bolt towards the support 32 and thus urges the limbs 38 of the rail 34 away from each other and so reduces play between the race track grooves 40 and 41 and the balls 42. Rotation of the bolt 44 anti-clockwise will cause the cone 47 to be moved lengthwise of the bolt away from the support 32 and will increase the play.
Figure 3 shows first and second assemblies 50 and 51, each assembly including a support 52, 53 and a longitudinally extending guide rail 54, 55.
The guide rail 54 is of open channel section and made from sheet metal so as to be resiliently flexible. In cross-section the guide rail 54 is symmetrical and comprises a base 56 which is secured to the support 52 and two limbs 57 which extend towards the other assembly 51. Guide rail 55 is a solid block which is rectangular in crosssection and is secured to the support 53, one of the longer sides abutting the support 53. The surfaces of the shorter sides of the guide rail 55 are opposed to the surfaces of the limbs 57 of the guide rail 54 facing one another, so forming two pairs of opposed surfaces. In each of the surfaces of the pairs of opposed surfaces is a longitudinally extending race track groove 58, 59 accommodating one of two rows of balls 60. One row of balls 60 is disposed to roll along the race track groove 58 of one limb 57 of the rail 54 and along the race track groove 59 of one of the shorter sides of the rail 55, and the other row of balls is disposed to roll along the the race track groove 58 of the other limb 57 of the rail 54 and along the race track groove 59 of the other shorter side of the rail 55. This construction of the two assemblies 50 and 51 allows longitudinal movement (perpendicular to the plane of the drawing) of one assembly with respect to the other.
The base 56 of the guide rail 54 is curved in cross-section, it curving inwardly between the two limbs 57 of the rail. An elongate screw-threaded member 61, such as a bolt, extends in a direction which lies between the limbs 57 of the guide rail 54. It has a head abutting the side of the support 52 facing away from the other support 53 and a shank extending with clearance through a bore 62 in the support 52 and into a correspondingly screw-threaded aperture 63 in the base 56 of the guide rail 54. The aperture 63 is positioned at the crown of the curvature of the base 56. Rotation of the bolt 61 (clockwise for a conventional right hand thread) will draw the base 56 towards the support 52, causing the base to flatten and the limbs 57 to be urged towards one another so reducing play between the race track grooves 58 and 59 and the balls 60. Rotation of the bolt anticlockwise will allow the limbs to move away from one another so increasing the play.

Claims (11)

1. First and second assemblies arranged for movement with respect to one another by two rows of rolling elements, each assembly having two tracks, one track accommodating one row and the other track accommodating the other row of the rolling elements, the first assembly including a resiliently flexible guide rail which in cross-section comprises a base, which is secured to a support of the first assembly, and two limbs extending towards the second assembly, the two limbs providing the tracks of the first assembly, and an elongate screw-threaded member which is provided for adjusting the play between the tracks and the rolling elements, rotation of the screwthreaded member causing the limbs of the guide rail to be urged towards or away from one another, wherein the screw-threaded member engages the support of the first assembly and extends in a direction which lies between the limbs of the guide rail.
2. First and second assemblies as claimed in Claim 1, in which the rolling elements are disposed to roll along the surfaces of the limbs of the guide rail facing towards one another, wherein the base of the guide rail curves into between the limbs of the rail, and the screw-threaded member engages the curved base such that, when the screw-threaded member is rotated in one direction, clockwise or anti-clockwise, the base of the guide rail is flattened which causes the limbs of the guide rail to be urged towards one another.
3. First and second assemblies as claimed in Claim 1, in which the rolling elements are disposed to roll along the surfaces of the limbs of the guide rail facing away from one another, wherein the screw-threaded member extends between the limbs of the guide rail, and an adjusting element, having converging surfaces engaging the surfaces of the limbs of the guide rail facing towards one another, is screwed on to the screw-threaded member, all such that when the screw-threaded member is rotated in one direction, clockwise or anti-clockwise, the adjusting element moves in one direction lengthwise of the screw-threaded member and urges the limbs of the guide rail away from one another.
4. First and second assemblies as claimed in Claim 3, wherein the adjusting element is a truncated cone.
5. First and second assemblies as claimed in any preceding claim, wherein each assembly includes a guide rail providing two tracks accommodating the rows of the rolling elements, and each guide rail is symmetrical in crosssection.
6. First and second assemblies substantially as herein described with reference to and as shown in Figure 1, or with reference to and as shown in Figure 2, of with reference to and as shown in Figure 3 of the accompanying drawings.
7. Guide means for the mutual displacement of at least two structural elements capable of translational movement such as a telescopic unit, wherein the two guide rails respectively cooperate via two rows of rolling bodies provided between them, at least one of the two guide rails consists of a flexurally resilient material, in particular sheet metal, and is of substantially U-shaped crosssection, and the rolling bodies roll along the side pieces of this guide rail, and wherein the guide play is adjustable by means of an adjusting screw or the like passing through the U-shaped guide rail, wherein the adjusting screw passes at least partly through the base part in such a way that it clamps the side pieces of the U-shaped guide rail against the rows of rolling bodies, the adjusting screw being anchored to a rigid structural member against which the base part of the U-shaped guide rail bears.
8. Guide means according to Claim 7, wherein the base part of the U-shaped guide rail outwardly embracing the rolling bodies is of inwardly curved shape in the direction away from the bearing point at the rigid structural member, and the adjusting screw engages against the curvature.
9. Guide means according to Claim 8, wherein the guide rails are laterally symmetrical to one another in cross-section and the adjusting screw engages against the crown of the curvature.
10. Guide means according to Claim 7, wherein at its end situated between the side pieces of the U-shaped guide rail inwardly embracing the rolling bodies the adjusting screw has an adjusting cone which bears against each one of the inwardly projecting surfaces of the side pieces of the guide rail.
11. Guide means according to Claim 10, wherein the guide rails are laterally symmetrical to one another in cross-section and the adjusting cone is a body of revolution.
GB08330139A 1982-11-13 1983-11-11 Two assemblies relatively moveable by means of rolling elements Expired GB2132286B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE8232003 1982-11-13

Publications (3)

Publication Number Publication Date
GB8330139D0 GB8330139D0 (en) 1983-12-21
GB2132286A true GB2132286A (en) 1984-07-04
GB2132286B GB2132286B (en) 1986-06-18

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ID=6745575

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08330139A Expired GB2132286B (en) 1982-11-13 1983-11-11 Two assemblies relatively moveable by means of rolling elements

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FR (1) FR2536136A1 (en)
GB (1) GB2132286B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2824500B1 (en) * 2001-05-09 2003-08-15 Lurem Machines A Bois GUIDE RAIL FOR SLIDING SUPPORT BENCH AND TOOL MACHINE COMPRISING SAME

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1074404A (en) * 1965-04-28 1967-07-05 N T N Bearings Birfield Ltd Improvements in or relating to bearings
GB1287655A (en) * 1969-07-01 1972-09-06 Black & Decker Mfg Co A radial arm saw and carriage construction

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360306A (en) * 1965-03-11 1967-12-26 Davidson Optronics Inc Slide bearing assembly

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1074404A (en) * 1965-04-28 1967-07-05 N T N Bearings Birfield Ltd Improvements in or relating to bearings
GB1287655A (en) * 1969-07-01 1972-09-06 Black & Decker Mfg Co A radial arm saw and carriage construction

Also Published As

Publication number Publication date
FR2536136A1 (en) 1984-05-18
GB8330139D0 (en) 1983-12-21
GB2132286B (en) 1986-06-18

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PCNP Patent ceased through non-payment of renewal fee