GB2111588A

GB2111588A - Flexible mountings

Info

Publication number: GB2111588A
Application number: GB08133958A
Authority: GB
Inventors: Friedrich Lob
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1981-11-11
Filing date: 1981-11-11
Publication date: 1983-07-06
Also published as: DE8231564U1

Abstract

A flexible mounting for connecting two components comprises an elastomeric element 1 acting between opposed end members 2, having shank portions 5 (Figure 4), for attachment to the components and connecting means 3 extending between the end members to provide a lost motion, connection therebetween. The connecting means 3 comprises flexible but substantially inextensible material extending between the end members 2 such that the length 8a of the material is greater than the axial distance between the end members 2 thereby allowing relative angular movement between the components within pre-set limits but prevent complete separation of the components in the event of failure of the mounting. The flexible mounting may be used in a mounting for a wind surfer mast 20. <IMAGE>

Description

SPECIFICATION Flexible mountings This invention concerns improvements in or relating to flexible mountings.

According to one aspect of the present invention a flexible mounting comprises an elastomeric element acting between and secured to a pair of opposed end members and connecting means extending between the end members, the connecting means being constructed and arranged to allow relative angular movement between the end members within pre-set limits and to restrict separation of the end members.

The relative angular movement between the end members to be accommodated mainly comprises bending about a plane transverse to the longitudinal axis of the mounting but may also include rotation about an axis generally parallel to the longitudinal axis of the mounting.

The connecting means preferably comprises a flexible but substantially inextensible material e.g.

metal or fabric strip, arranged to provide a lost motion connection between the end members.

A piece of strip material may be attached at each free end to a respective one of the end members or formed into a closed loop and the end members attached to the loop at two circumferentially spaced positions. In either case the or each length of the material extending between the end members is chosen to exceed the axial length of the mounting to provide a degree of slack or free play which constitutes the lost motion connection. The amount of slack or free play determines the extent of relative angular movement between the end members that can be accommodated and may be varied to give any required range of angular movement.

Preferably the elastomeric element is formed solely from an elastomer e.g. rubber, having the required hardness, resilience characteristics for a given application. However, for certain applications the elastomeric element may include a reinforcement.

The elastomeric element is preferably of annular cross-section along its length which may be constant i.e. the element may be cylindrical or vary along the length i.e. the element may be of generally hourgiass configuration.

Other configurations of elastomeric element are possible, however, for example the element may be of square, rectangular, oval, hexagonal etc.

cross-section which may be constant or vary along its length.

The end elements may be similar or different but in general will include a head portion attached to the end face of the elastomeric element, e.g. by bonding, or embedded in the end of the elastomeric element and means for attaching the head portion to one of the components to be connected by the mounting. The attachment means may comprise a shank portion extending from the head portion outwards of the mounting.

The shank portion may be externally threaded for engagement either in an internally threaded bore or aperture or with a lock nut.

According to a further aspect of the present invention there is provided a wind surfer comprising a mast adapted to carry a sail and a board, the mast being secured to the board by the flexible mounting according to the first aspect of the invention.

Preferably the mounting is constructed and arranged to accommodate angular movement of the mast relative to the board in a plane transverse to the length of the mast of approximately 1 8or and in any direction through 360" about the axis of the mounting.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings wherein Figure 1 is a side view of a flexible mounting according to the present invention; Figure 2 is a section, to an enlarged scale, on the line 2-2 of Figure 1; Figure 3 is a perspective view of part of a wind surfer incorporating the flexible mounting of Figures 1 and 2, and Figure 4 shows to an enlarged scale, and partly in section, the mast/hull connection of the wind surfer shown in Figure 3.

The flexible mountings shown in Figures 1 and 2 of the accompanying drawings comprises a rubber element 1 of generally hourglass configuration acting between a pair of opposed end members 2 and connecting means 3 extending between the end members 2.

Each end member 2 is similar and comprises a flat annular head portion 4 embedded in the rubber element 1 adjacent to an end thereof and a shank portion 5 extending from the head portion 4 outwards of the rubber element 1 for securing the mounting to a component.

The connecting means 3 comprises an elongate fabric strip 6 incorporating longitudinally extending substantially inextensible cords (not shown) the free ends of which are joined e.g. by stitching, as indicated by reference numeral 7 to form a closed loop 8 which is positioned around the outside of the element 1 with the shank portions 5 projecting through eyelets 9 provided in the strip 6.

As shown the length of loop portions 8a extending between the shank portions 5 on opposite sides of the mounting is greater than the axial length L of the mounting thereby providing a degree of slack or free play in the loop portions 8a which serves a dual purpose. Firstly relative angular movement between the end members 2 within pre-set limits is unrestricted, secondly complete separation of the end members 2, e.g.

following failure of the rubber element 1 or the attachment between the rubber element 1 and the end member(s) 2, is prevented.

Both characteristics are controlled by the length of the loop portions 8a which determines the amount of free play or slack in the loop portions available to be taken up as a result of relative movement between the end members before a loop portion is fully extended and further relative movement between the end members is prevented by the inextensibility of the loop portion.

The mounting according to the present invention is therefore particularly suited for applications in which angular movement over a wide range between the components connected by the mounting is required coupled with a failsafe feature preventing complete separation of the components in the event of failure of the mounting.

One such application shown in Figures 3 and 4 of the accompanying drawings is the mast to board connection in a wind surfer. The shank portions 5 of the mounting end members 2 are externally screw-threaded and received in internally screw-threaded bores in the end of the mast 20 and a cylindrical plastic bearing 21 mounted in an opening 22 in the upper surface of the board 23 to secure the mast to the board and clamp the portions of the loop including the eyelets 9 at either end of the mounting between the ends of the mounting and the adjacent wind surfer component. The bearing 21 allows the mast 20 to rotate through 3600 about the axis of the mounting.

As shown in Figure 4 the length of the loop portions 8a on opposite sides of the mounting are chosen to allow angular movement of the mast 20 relative to the board 23 of up to 900 to either side of the normal vertical, i.e. total angular movement of 1800, whereupon a loop portion 8a is fully extended and further relative movement is prevented by the inextensibility of that loop portion. This angular movement which may occur in any direction through 3600 about the axis of the mounting results in the end member 2 associated with the mast 20 bending relative to the opposite end member 2 about a plane transverse to the longitudinal axis of the mounting giving rise to frequent changes in the loading of the rubber element 1 which may eventually result in failure of the rubber element 1 or of the attachment between the rubber element 1 and one or both of the end members 2.Under these circumstances complete separation of the mast 20 from the board 23 which may result in personal injury and/or loss of the mast and sail is prevented by the connecting means 3 which enables the user to sail the wind surfer back to shore.

The invention is not restricted to the abovedescribed mounting which may be modified in a number of ways. For example the connecting means may be formed from fabric or metal strip which may be formed into a closed loop as described or attached at each free end to a respective one of the end members e.g by means of eyelets provided at the ends of the piece.

The connecting means may comprise more than one closed loop as described or one or more individual strips. The end members may be attached to the end faces of the mounting e.g. by bonding. The elastomeric element may be made from any suitable elastomer e.g. natural rubber or polychloroprene and may include a reinforcement.

The configuration of the elastomeric element may be varied depending on the application of the mounting.

Finally although the mounting has been described in connection with its application to wind surfers it will be appreciated that it has uses in other fields, for example as a mounting for instruments or machinery.

Claims (Filed on 26 Jan., 1982) 1. A flexible mounting comprising an elastomeric element acting between and secured to a pair of opposed end members and connecting means extending between the end members, the connecting means being constructed and arranged to allow relative angular movement between the end members within pre-set limits and to restrict separation of the end members.

2. A mounting according to claim 1 wherein the connecting means comprises a flexible, substantially inextensible material arranged to provide a lost motion connection between the end members.

3. A mounting according to claim 2 wherein said inextensible material comprises a metal or fabric strip attached at each free end to a respective one of the end members.

4. A mounting according to claim 2 wherein said inextensible material comprises a metal or fabric strip formed into a closed loop attached to the end members at two circumferentially spaced positions.

5. A mounting according to claim 3 or claim 4 wherein the or each length of metal or fabric strip extending between the end members exceeds the axial length of the mounting between the end members to provide a degree of slack or free play which constitutes the lost motion connection.

6. A mounting according to any one of the preceding claims, wherein the elastomeric element consists solely of elastomer e.g. natural or synthetic rubber.

7. A mounting according to any one of the preceding claims wherein the elastomeric element is of uniform cross-section along its length.

8. A mounting according to any one of claims 1 to 6 wherein the elastomeric element is of nonuniform cross-section along its length.

9. A mounting according to any one of the preceding claims wherein each end member has a head portion attached to the end face of the elastomeric element and a shank portion for attaching the head portion to one of the components to be connected by the mounting.

10. A flexible mounting substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

11. A wind surfer comprising a mast adapted to carry a sail and a board, the mast being secured to the board by a flexible mounting according to any one of the preceding claims.

1 2. A wind surfer according to claim 11 wherein the mounting is constructed and arranged to accommodate angular movement of

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Claims

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relative movement between the end members is prevented by the inextensibility of the loop portion.

The mounting according to the present invention is therefore particularly suited for applications in which angular movement over a wide range between the components connected by the mounting is required coupled with a failsafe feature preventing complete separation of the components in the event of failure of the mounting.

One such application shown in Figures 3 and 4 of the accompanying drawings is the mast to board connection in a wind surfer. The shank portions 5 of the mounting end members 2 are externally screw-threaded and received in internally screw-threaded bores in the end of the mast 20 and a cylindrical plastic bearing 21 mounted in an opening 22 in the upper surface of the board 23 to secure the mast to the board and clamp the portions of the loop including the eyelets 9 at either end of the mounting between the ends of the mounting and the adjacent wind surfer component. The bearing 21 allows the mast 20 to rotate through 3600 about the axis of the mounting.

As shown in Figure 4 the length of the loop portions 8a on opposite sides of the mounting are chosen to allow angular movement of the mast

20 relative to the board 23 of up to 900 to either side of the normal vertical, i.e. total angular movement of 1800, whereupon a loop portion 8a is fully extended and further relative movement is prevented by the inextensibility of that loop portion. This angular movement which may occur in any direction through 3600 about the axis of the mounting results in the end member 2 associated with the mast 20 bending relative to the opposite end member 2 about a plane transverse to the longitudinal axis of the mounting giving rise to frequent changes in the loading of the rubber element 1 which may eventually result in failure of the rubber element 1 or of the attachment between the rubber element 1 and one or both of the end members 2.Under these circumstances complete separation of the mast 20 from the board 23 which may result in personal injury and/or loss of the mast and sail is prevented by the connecting means 3 which enables the user to sail the wind surfer back to shore.

The invention is not restricted to the abovedescribed mounting which may be modified in a number of ways. For example the connecting means may be formed from fabric or metal strip which may be formed into a closed loop as described or attached at each free end to a respective one of the end members e.g by means of eyelets provided at the ends of the piece.

The connecting means may comprise more than one closed loop as described or one or more individual strips. The end members may be attached to the end faces of the mounting e.g. by bonding. The elastomeric element may be made from any suitable elastomer e.g. natural rubber or polychloroprene and may include a reinforcement.

The configuration of the elastomeric element may be varied depending on the application of the mounting.

Finally although the mounting has been described in connection with its application to wind surfers it will be appreciated that it has uses in other fields, for example as a mounting for instruments or machinery.

Claims (Filed on 26 Jan., 1982) 1. A flexible mounting comprising an elastomeric element acting between and secured to a pair of opposed end members and connecting means extending between the end members, the connecting means being constructed and arranged to allow relative angular movement between the end members within pre-set limits and to restrict separation of the end members.
2. A mounting according to claim 1 wherein the connecting means comprises a flexible, substantially inextensible material arranged to provide a lost motion connection between the end members.
3. A mounting according to claim 2 wherein said inextensible material comprises a metal or fabric strip attached at each free end to a respective one of the end members.
4. A mounting according to claim 2 wherein said inextensible material comprises a metal or fabric strip formed into a closed loop attached to the end members at two circumferentially spaced positions.
5. A mounting according to claim 3 or claim 4 wherein the or each length of metal or fabric strip extending between the end members exceeds the axial length of the mounting between the end members to provide a degree of slack or free play which constitutes the lost motion connection.
6. A mounting according to any one of the preceding claims, wherein the elastomeric element consists solely of elastomer e.g. natural or synthetic rubber.
7. A mounting according to any one of the preceding claims wherein the elastomeric element is of uniform cross-section along its length.
8. A mounting according to any one of claims 1 to 6 wherein the elastomeric element is of nonuniform cross-section along its length.
9. A mounting according to any one of the preceding claims wherein each end member has a head portion attached to the end face of the elastomeric element and a shank portion for attaching the head portion to one of the components to be connected by the mounting.
10. A flexible mounting substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.
11. A wind surfer comprising a mast adapted to carry a sail and a board, the mast being secured to the board by a flexible mounting according to any one of the preceding claims.
1 2. A wind surfer according to claim 11 wherein the mounting is constructed and arranged to accommodate angular movement of

the mast relative to the board in a plane transverse to the length of the mast of approximately 1800.
13. A wind surfer according to claim 11 or claim 12 including means to allow rotation of the mast through 360" about the axis thereof.

1 4. A wind surfer according to claim 1 3 wherein said means comprises a bearing acting between the mounting and the board.

1 5. A wind surfer substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.