GB2092263A

GB2092263A - Improvements in or Relating to Flexible Couplings

Info

Publication number: GB2092263A
Application number: GB8103032A
Authority: GB
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1981-01-31
Filing date: 1981-01-31
Publication date: 1982-08-11
Also published as: GB2092263B; JPS57146919A

Abstract

A flexible coupling (5) for connecting two rotatable components (6, 7) e.g. driving and driven shafts, comprises a torque transmitting element consisting of at least one annular ring member (1, 1') and attachment means (8) engageable with the element at two circumferentially opposed regions for securing the element to the rotatable components (6, 7). The or each ring member (1, 1') is deformable in the radial direction of the ring member to accommodate relative axial movement between the components (6, 7) but has substantial resistance to deformation in an axial direction normal thereto to transmit torque between the components (6, 7). <IMAGE>

Description

SPECIFICATION Improvements in or Relating to Flexible Couplings This invention concerns improvements in or relating to flexible couplings for transmitting torque between two rotatable components, for example driving and driven shafts.

According to the present invention a flexible coupling for transmitting torque between two rotatable components comprises a torque transmitting element consisting of at least one annular ring member and attachment means engageable with the ring member at two circumferentially opposed regions for securing the ring member to the rotatable components, said ring member being deformable in a radial direction of the ring member for accommodating relative axial movement between said components and having substantial resistance to deformation in an axial direction normal thereto for transmitting torque between said components.

Preferably the ring member is formed from metal strip e.g. steel. For a particular application the ring member may comprise a single loop of metal strip of the required width and thickness, but more preferably the ring member comprises a plurality of loops of metal strip, preferably with inter-leaving layers of elastomeric or polymeric material, each loop being of similar width but reduced thickness as compared with an equivalent single loop member. A member comprising a plurality of loops may be formed from a single strip having a layer of the elastomeric or polymeric material e.g. PTFE, bonded to one surface, the strip being wound around a former and the ends fastened by any suitable means prior to assembly.

Preferably the attachment means comprises a respective retainer plate for clamping the ring member to the associated rotatable component or a part secured thereto. To facilitate assembly and improve torque transmission-the-ring member is preferably received in a complementary recess in the retainer plate and/or the associated rotatable component or part whereby the ring member is positively locked for rotation with the rotatable components or parts. The above-described method of attachment avoids the use of bolts or the like extending through the ring member thereby reducing undesirable stress loading of the ring member under applied torque forces.

Preferably the torque transmitting element comprises a plurality of such ring members nested one within the other and overlapping at two circumferentially opposed regions at which the element is secured to the rotatable components.

In one preferred construction the torque transmitting element comprises two such ring members disposed with their longitudinal axes normal to one another.

The invention will now be described in more detail by way of example only with reference to the accompanying schematic drawings in which: Figure 1 is an end view of a torque transmitting element for a coupling in accordance with the present invention; Figure 2 is a side view, partly cut away, of a coupling according to the present invention, and Figure 3 is an end view of the coupling shown in Figure 2.

The torque transmitting element shown in Figure 1 of the accompanying drawings comprises an annular ring member 1 formed of high carbon steel strip 2, preferably having a thickness less than 1 mm and a width to thickness ratio of at least 20:1, coated on one surface with PTFE and wound to form a laminate structure comprising a plurality of loops. The free ends 3, 4 of the strip are secured, for example by tape, to maintain the annular shape of the member 1 prior to assembly. The member 1 being made of thin steel strip, is relatively deformable in the radial direction thereof but has a width such that there is substantial resistance to deformation in an axial direction normal thereto.

Referring now to Figures 2 and 3 there is shown a coupling 5 for connecting driving and driven shafts 6 and 7 respectively incorporating two of the ring members 1, 1' shown in Figure 1.

The ring members 1, 1' are nested one within the other with their longitudinal axes L, L' normal to one another. The members 1, 1' overlap one another at two circumferentially opposed regions and are secured at each region of overlap to a respective one of the driving and driven shafts 6 and 7 by an associated retainer plate 8.

Each retainer plate 8 is flat and generally crossshaped having a central annular boss 8a and four radially projecting apertured lugs (not shown) uniformly spaced around the outer periphery of the boss. Each boss 8a is formed with a transversely extending recess 8d of channel section complementary to the inner ring member 1'.

Each shaft 6, 7 is provided with four radially projecting apertured lugs 9 uniformly spaced around the outer periphery of the shaft adjacent to the end thereof. The end portion of each shaft 6, 7 is formed with a transversely extending recess (not shown) of channel section complementary to the outer ring member 1.

On assembly the inner and outer ring members 1', 1 are located at each region of overlap in the recesses in the associated retainer plate 8 and shaft 6, 7 respectively and the lugs of each retainer plate are axially aligned with the lugs 9 of the associated shaft. Aligned lugs project into the gaps between the members 1, 1' and are connected by a respective bolt (not shown) passing through the apertures thereof.

Tightening the bolts to clamp the members 1, 1' between the retainer plates and the shaft ends radially deforms the members from their circular profile to an elliptical profile (Figure 2) the major axis of which is transverse to the axis of rotation of the coupling. The ends 3, 4 of the strip forming each member 1, 1' are retained between the retainer plates and the shaft ends. The edges of the retainer plates 8 and the shaft ends are radiused (Figure 2) to avoid generation of high stresses in the members 1, 1' during deformation thereof.

In use the ring members 1, 1' are deformable in the radial direction thereof to accommodate relative axial movement between the shafts but are substantially rigid when subjected to rotation about an axis parallel to the axis of rotation of the coupling for transmitting torque between the shafts.

Claims

1. A flexible coupling for transmitting torque between two rotatable components comprises a torque transmitting element consisting of at least one annular ring member and attachment means engageable with the ring member at two circumferentially opposed regions for securing the ring member to the rotatable components, said ring member being deformable in a radial direction of the ring member for accommodating relative axial movement between said components and having substantial resistance to deformation in an axial direction normal thereto for transmitting torque between said components.

2. A coupling according to Claim 1 wherein the ring member is formed of metal.

3. A coupling according to Claim 1 or Claim 2 wherein the ring member is formed of metal strip.

4. A coupling according to Claim 3 wherein the strip has a thickness less than 1 mm and a width:thickness ratio of at least 20:1.

5. A coupling according to Claim 3 or Claim 4 wherein the ring member comprises a plurality of loops of metal strip.

6. A coupling according to any one of Claims 2 to 5 wherein the strip is coated on one surface with an elastomeric or polymeric material.

7. A coupling according to any one of the preceding Claims wherein the attachment means comprises a respective retainer plate for clamping the ring member to the associated component or part secured thereto.

8. A coupling according to Claim 7 wherein the ring member is received in a complementary recess in the retainer plate and/or associated component or part.

9. A coupling according to any one of the preceding Claims comprising two ring members nested one within the other and overlapping at two circumferentially opposed regions.

10. A coupling according to Claim 9 where the ring members are disposed with their longitudinal axes normal to one another.

11. A flexible coupling substantially as herein described with reference to the accompanying drawings.