GB2119477A

GB2119477A - Membrane-type couplings

Info

Publication number: GB2119477A
Application number: GB08308520A
Authority: GB
Inventors: Norman James Morrison
Original assignee: Flexibox Ltd
Current assignee: Flexibox Ltd
Priority date: 1982-04-02
Filing date: 1983-03-28
Publication date: 1983-11-16
Also published as: GB2119477B; GB8308520D0

Abstract

A membrane type coupling (10) has co-axial input and output members (12, 14), intermediate member (16) and pair of spacers (18, 20), the input and output members (12, 14) being connected to respective spacers (18, 20) and the intermediate member (16) being connected at either end to both spacers (18, 20) by membrane packs (22, 36, 38, 66, 54, 56). The connection between each spacer and at least one member comprising a pair of axially spaced packs (36, 38, 54, 56). The coupling (10) thus has lateral rigidity but angular and substantial axial flexibility. <IMAGE>

Description

SPECIFICATION Improvements in membrane type couplings This invention relates to couplings between rotating shafts and particularly to those which allow a certain degree of axial misalignment and/or movement between the two shafts.

Interengaging splined shafts fulfil this function but they require lubrication if there is much movement between the two shafts and indeed even if there is only a little. If there is normally only a little movement a step can form on the splines preventing or at least hindering further axial movement on the few occasions this may occur.

Also, within normal manufacturing tolerances there is inevitably a certain degree of lost motion between the two shafts which thus allows a backlash to develop between them. A presently available coupling comprising membranes disposed radially between interjacent flanges on the two shafts solves many of these drawbacks. it can be built torsionally rigid within wide tolerances; it requires no lubrication and it does not wear. Furthermore it can accept angular misalignment between the shafts.

However beyond fairly small limits of axial movement the axial loads on the shafts increase considerably. In other words these membranes do not allow adequate axial movement for some applications.

Joining couplings together does not help if the coupling is rendered laterally unstable.

It is an object of this invention therefore to provide a membrane-type coupling having both lateral stability and increased axial movement capability.

In accordance with this invention there is provided a rotary coupling comprising an input and output member connectible to a driving and a driven shaft respectively, an intermediate member disposed concentrically with respect to the input and output members, a pair of spacers disposed concentrically with respect to the intermediate member, substantially radially disposed membrane packs connecting the input and intermediate member to one spacer and the output and intermediate member to the other spacer, and in which the connection between each spacer and at least one member comprises a pair of axially spaced membrane packs.

The invention is further described hereinafter with reference to the accompanying drawing in which a coupling according to the invention is shown in section.

The coupling 10 comprises an input member 12 and an ouput member 14, the input member being adapted for connection with a driving shaft and the output member for connection with a driven shaft, neither of which is shown in the drawing. The coupling transmits torque from the driven to the driving shaft and is torsionally rigid.

The coupling 10 further comprises an intermediate member 16 and two floating spacers 1 8 and 20 which are each concentric with the input and output members 12, 14.

The input member 12 is connected to the floating spacer 18 by an annular membrane pack 22 which comprises a laminate of sheet steel lamellae. The membrane pack 22 is clamped between two rings 24, 26 which constitute the input member 12. Similarly the floating spacer 1 8 comprises a number of rings 28, 30, 32, 34 which are clamped together and between rings 28 and 30 of which the membrane pack 22 is held. The rings 30, 32 and 34 clamp between themselves a pair of spaced membrane packs 36, 38 which are also clamped between rings 40, 42 and 44 forming part of the intermediate member 1 6. The membrane packs 36, 38 each comprise a laminate as the pack 22 but in this instance each contains fewer lamelle and so offers less resistance to axial thrust.Indeed if each comprises half the number of lamellae as the pack 22 then the combined membranes 36, 38 would have the same axial deflection characteristics as the single pack 22.

The purpose of essentially splitting a single pack to form a pair 36, 38 of spaced membranes is to provide a laterally and angularly rigid connection between the spacer 1 8 and the intermediate member 16. Nevertheless the pair 36, 38 and the membrane 22 allow axial movement between intermediate member 1 6 and input member 12.

The intermediate member 1 6 further comprises a torque tube 46 which could however be omitted to shorten the coupling 10. The torque tube 46 is connected to the ring 44 and to a further set of rings 48, 50, 52 which together clamp a further pair of spaced membranes 54, 56. These are clamped to the floating spacer 20 around its periphery by rings 58, 60, 62 which together with a further ring 64 form the floating spacer 20.

Between rings 62, 64 a membrane pack 66 is clamped and the outer periphery of this membrane is clamped between two rings 68, 70 forming the output member 1 4.

It will be appreciated from the drawing that the arrangement of the output member 14, the floating spacer 20, the intermediate member 1 6 and their interconnections is essentially the same as that for the input member 12, floating spacer 18, intermediate member 16 and their interconnections as described in detail above.

Thus the connection between the spacer 20 and intermediate member 1 6 is both laterally and angularly rigid and this, together with the connection between the spacer 1 8 and intermediate member 16, renders the coupling 10 as a whole, although no laterally rigid, at least laterally stable. This means that while the input and output members may be supported on their respective shafts the rest of the coupling does not require any further external support in the lateral direction. The coupling is however angularly flexible at both ends and consequently, not only can it accept angular misalignment between the shafts attached to the input and output members but also it can accept lateral misalignment between those shafts.

It should be appreciated however that the provision of the spaced membranes 36, 38 or 54, 56 need not necessarily be between the intermediate member 1 6 and the spacers 1 8 and 20 respectively. They could instead and without altering the overall characteristics of the coupling 10 be disposed between the input and output members 12 and 14 and the spacers 18 and 20 respectively with single membranes connecting the intermediate member 1 6 to the floating spacers 1 8, 20. Indeed their disposition may be mixed such that, referring to the drawing, the left hand side of the coupling 10 could be as illustrated while the right hand side, for instance, could have the double membrane pack 54, 56 disposed between the spacer 20 and output member 14.

The rings comprising the various members and spacers may be clamped together by any convenient means. For instance a number of peripheral bolts 72 may be used or the rings may be riveted together as at 74.

Claims

1. A rotary coupling comprising an input and output member connectible to driving and a driven shaft respectively, an intermediate member disposed concentrically with respect to the input and output members, a pair of spacers disposed concentrically with respect to the intermediate member, substantially radially disposed membrane packs connecting the input and intermediate member to one spacer and the output and intermediate member to the other spacer, and in which the connection between each spacer and at least one member comprises a pair of axially spaced membrane packs.

2. A coupling as claimed in claim 1 wherein the connection between each spacer and one member comprises a pair of axially spaced membrane packs and the connection between each spacer and the other member comprises a single membrane pack.

3. A coupling as claimed in claim 2 wherein the axial thickness of the single membrane pack is substantially the same as the combined axial thickness of the pair of membrane packs.

4. A coupling as claimed in claim 2 or 3 in which said pair of membrane packs connects the intermediate member to each spacer and the single membrane pack connects each spacer to respective input and output members.

5. A coupling as claimed in any preceding claim wherein the input, output and intermediate members have substantially the same radial dimensions and wherein the spacers have smaller radial dimensions.

6. A coupling as claimed in any preceding claim wherein the input, output and intermediate members and the spacers each comprise a plurality of rings and means securing said rings together and clamping therebetween said membrane packs.

7. A coupling substantially as hereinbefore described with reference to the accompanying drawing.