GB1588869A

GB1588869A - Wire-drawing pulleys

Info

Publication number: GB1588869A
Application number: GB3986776A
Authority: GB
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1977-09-23
Filing date: 1977-09-23
Publication date: 1981-04-29

Description

(54) WIRE-DRAWING PULLEYS (71) We, SMITHS INDUSTRIES LIMITED, a British Company of Cricklewood, London NW2 6JN, 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 wire-drawing pulleys.

According to one aspect of the present invention, there is provided a wire-drawing pulley comprising supporting means to be rotated about an axis, and a ceramic annulus which is coaxially mounted on the supporting means by a clamping member for rotation with the supporting means and the clamping member about the said rotational axis, wherein the clamping member overlies a side of the ceramic annulus and is clamped to a surface of the supporting means to mount the ceramic annulus on the supporting means, and wherein deformable means is deformably mounted between the clamping member and the ceramic annulus, and between the clamping member and the said surface of the supporting means.

The deformable means may be resilient.

The deformable means may be a unitary member, and may be in the form of a disc of. for example. neoprene-coated nylon, nitrile rubber. or paper.

Preferably. the clamping member completely overlies the said side of the ceramic annulus, in which case the deformable means may also completely overlie the side of the ceramic annulus.

The said surface of the supporting means may extend substantially transversely of said rotational axis.

The supporting means may include a part which extends substantially transversely of said rotational axis and which overlies the other side of said ceramic annulus. A further deformable means may be deformably mounted between said other side of the ceramic annulus and the said part.

An annular gap may be provided between the inner peripheral surface of the ceramic annulus and the supporting means.

The said pulley may comprise a plurality of ceramic annuli mounted coaxially on the supporting means in echelon for rotation with said supporting means about said rotational axis. In such a case each of at least two of the ceramic annuli is clamped between a pair of clamping members mounted on the supporting means with one of the clamping member overlying one side of the annulus while the other clamping member overlies the other side of the annulus and is clamped to a surface of the supporting means to mount the annulus thereon, there being deformable means deformably mounted between the said other clamping member and both the said other side of the annulus and the said surface of the supporting means.

Two wire-drawing pulleys in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is an elevation of a wire-drawing pulley partly in cross-section; and Figure 2 is an elevation of another wiredrawing pulley, partly in cross-section.

A wire-drawing pulley generally comprises a supporting member which is to be rotated about an axis, and at least one ceramic annulus mounted coaxially on the supporting member, so as to rotate with the member about its rotational axis. to provide a wire-engaging surface of the pulley.

With reference to Figure 1, there is shown a wire-drawing pulley having a single ceramic annulus to provide the wire-engaging surface. The pulley includes a generally tubular supporting member 10. of, for example, steel or aluminum. having an axial bore 11 through which a rotatable drive shaft (not shown) is to extend, the drive shaft being mechanically coupled to the supporting member 10 to rotate the member 10 about its longitudinal axis.

The supporting member 10 has mounted thereon a ceramic annulus 12 of substantially rectangular cross-section whose outer peripheral surface provides the wireengaging surface of the pulley. The ceramic annulus 12 is coaxially mounted on the member 10 for rotation with the member 10 about its rotational axis with the sides 13 and 18 of the ceramic annulus 12 extending transversely of the rotational axis. The annulus 12 is clamped in position on the member 10 between a substantially flat surface 15 of an integral portion 14 of the member 10 and a substantially flat surface 22 of a clamping ring 19 which completely overlies the side 18 of the ceramic annulus 12. The surface 15 of the portion 14, extends substantially transversely of the rotational axis of the supporting member 10, and completely overlies the other side 13 of the annulus 12.A deformable washer 24 of cotton-based cartridge paper is disposed between the side 13 of the annulus 12 and the surface 15 in order to improve clamping.

An annular gap 17 is provided between the inner peripheral surface of the ceramic annulus 12 and the supporting member 10 to accomodate relative radial movement between the annulus 12 and the member 10 resulting from thermal expansion which occurs during operation of the pulley.

The clamping ring 19 is mounted on a cylindrical surface 23 of the supporting member 10 to permit movement of the ring 19 axially of the member 1() but substantially to prohibit radial movement. The ring 19 is secured on the member 10 by means of a plurality of machine-screws 20 (only one of which is visible in the drawing). which can be tightened in order to move the clamping ring 19 towards the portion 14 and thereby achieve clamping of the ceramic annulus 12.

The screws 20 are spaced at intervals around a circumference of the clamping ring 1C) and extend axially of the member 1() through the ring 19 into respective threaded bores 21 in the supporting member 1().

The surface 22 of the clamping ring 19 extends beyond the side 18 of the ceramic annulus 12 to lie adjacent a radially extending surface 27 of the supporting member 10.

A deformable packing disc 28 of. for example, neoprene-coated nylon. is deformably mounted between the surface 22 of the clamping ring 19 and the side 18 of the ceramic annulus 12. and extends across the surface 22 to the interface between the surface 22 and the surface 27 of the supporting member 1().

In the particular pulley shown in Figure 1, it would be desirable for the surface 27 of the member 10 and the side 18 of the ceramic annulus 12 to lie in the same plane transversely of the rotational axis of the member 10. However, this alignment may not always be achieved in view of the accuracy with which, for example, the surface 27 and the side 18 of the annulus 12 can be machined, especially when the overall cost of the pulley is being kept to a minimum. As a result, the clamping ring 19 may tilt or twist when the screws 20 are tightened. In addition, the surface 22 of the ring 19 may not be completely flat, thereby resulting in a non-uniform clamping pressure being applied by the clamping ring 19 over the side 18 of the annulus 12.

Without the packing disc 28 in the pulley, these manufacturing inaccuracies may lead to the clamping pressure being applied to the side 18 of the ceramic ring 12 at localised regions, thereby creating considerable stresses in the ceramic material at those regions which may eventually lead to cracking or chipping of the ceramic material.

It has been found that by providing the deformable packing disc 28, any irregularities which occur between the surfaces affected by the aforementioned manufacturing inaccuracies are substantially accommodated upon tightening of the screws 20 by deformation of the packing disc 28, with the result that the clamping pressure is more evenly distributed over the side 18 of the ring 12 and the problems associated with manufacturing inaccuracies are substantially overcome.

The clamping ring 19 is in the form of a disc having an aperture therein and includes a flange 26 extending around the periphery thereof, which, together with a flange 16 on the portion 14, engage with respective portions of the outer peripheral surface of the ceramic annulus 12 to retain the annulus 12 coaxial with the rotational axis of the member 10. The outer peripheral surface of the ceramic annulus 12 has an annular groove 25 therein in which the wire to be drawn is confined during operation of the pulley.

The bore 21 may extend completely through the supporting member 10, and rivets used to secure the clamping ring 19 on the member 10 instead of the machine screws 20.

Referring now to Figure 2, there is drawn a wire-drawing pulley having a tubular supporting member which is to be rotated about a longitudinal axis. and a plurality of ceramic annuli mounted coaxially on the supporting member in echelon to provide individual. wire-engaging surfaces of the pulley. This type of wire-drawing pulley is commonly referred to as a wire-drawing cone.

The wire-drawing cone includes a tubular supporting member 30, of, for example, steel or aluminum, having an axial bore 31 through which a rotatable drive shaft (not shown in the drawing) is to extend, the drive shaft being mechanically coupled to the member 30 to rotate the member about its longitudinal axis.

The bore 31 increases in diameter towards one end 32 of the member 30, and the outer peripheral surface of the member 30, which is stepped, also increases in diameter towards that end 32, giving the supporting member 30 a generally conical shape. The outer peripheral surface of the member 30 has mounted thereon four ceramic annuli 33 to 36 of substantially rectangular crosssection whose outer peripheral surfaces provide the individual wire-engaging surfaces of the cone.

The four ceramic annuli 33 to 36 are clamped in echelon on the member 30 by five clamping rings 38 to 42 such that they extend parallel to one another and such that they are coaxial with the longitudinal axis of the member 30.

The largest diameter ceramic annulus, 33, is clamped between the two clamping rings 38 and 39. The clamping ring 39 is rigidly mounted on the member 30 by means of six machine-screws (not visible in the drawing) which screw into respective bores in the member 30. The clamping ring 38, however, is mounted on a cylindrical surface 40 of the member 30 so as to permit movement of the ring 38 axially of the member 30, but substantially to prohibit radial movement.

The ring 38 is secured on the member 30 by means of six machine-screws 43 (only one of which is shown) which can be tightened in order to move the clamping ring 38 axially of the member 30 towards the clamping ring 39. and thereby achieve clamping of the ceramic annulus 33. The screws 43 are spaced at intervals around a circumference of the ring 38 and extend in a direction parallel to the longitudinal axis of the member 30. through the ring 38. into respective. threaded bores 44 in the member 30.

The next largest diameter ceramic annulus, 34. is clamped between the clamping ring 40 and the rear surface of the clamping ring 39 in a similar manner to that described with reference to the ceramic annulus 33.

only in this case the clamping ring 40 is moved in the opposite sense to achieve clamping. The clamping ring 40 is mounted on a cylindrical surface 46 of the member 30 and is secured thereto bv means of six screws 47 (only one of which is shown in the drawings) which pass through the ring 40 into respective threaded bores 48 in the member 30.

The remaining ceramic annuli 35 and 36 are clamped in a manner identical to that described above with reference to the annulus 34 between the clamping rings 41 and 40.

and 42 and 41 respectively.

An annular gap 55 is provided between the inner peripheral surface of each of the ceramic annuli 33 to 36 and the outer peripheral surface of the member 30 to accomodate relative radial movement between the ceramic annuli and the member 30 resulting from thermal expansion which occurs during operation of the wire-drawing cone.

Each of the ceramic annuli 33 to 36 is clamped by a substantially flat, radiallyextending surface 45 on its associated clamping ring. The surfaces 45 of the clamping rings 38 to 42 extend across both the side of their associated ceramic annuli, for example, side 37 of the annulus 33, and, respective radially-extending surfaces 49 of the member 30. A deformable packing disc 56 of neoprene-coated nylon is deformably mounted between the surfaces 45 of each of the clamping rings and the side of its associated ceramic annulus and extends across the surface 45 to the interface between the surface 45 and the respective surface 49 of the member 30. Each of the deformable packing discs 56 acts in a similar manner to the previously described packing disc 28 substantially to overcome manufacturing inaccuracies similar to those discussed with reference to the pulley shown in Figure 1. For example.it would be desirable that the surface 49 be substantially aligned with, and parallel to. the side 37 of the annulus 33, and that the surface 45 be substantially flat. but, due to manufacturing inaccuracies. this may not be achieved. In such a case. the deformable packing disc 56 substantially accommodates any irregularities which may occur between the surface 49 and the side 37 as a result of those manufacturing inaccuracies.

Each of the clamping rings 38 to 42 is in the form of a disc having a central aperture therein. and includes an integral flange 50 which extends completely around the ring and engages with a portion of the outer peripheral surface of its respective ceramic annulus. In addition, the clamping rings 39, 40 and 41 each have a recess 51 in their rear surface in which a side of their adjacent ceramic annulus is received such that a shoulder 52 of each recess 51 also engages with a portion of the outer peripheral surface of the associated annulus. The flanges 50 and shoulders 52 serve to retain the ceramic annuli 33 to 36 coaxially on the supporting member 30.

The outer peripheral surface of each of the ceramic annuli 33 to 36 is provided with an annular groove in which the wire to be drawn is confined during operation of the pulley.

A thin, deformable washer 57 of, for example, cotton-based cartridge paper, is disposed between the ceramic annuli 33, 34, 35 and 36 and the clamping rings 38, 39, 40 and 41 respectively to improve clamping.

The deformable packing discs 28 and 56 described with reference to Figures 1 and 2 respectively of the drawings. may, alternatively, be of nitrile rubber, cartridge paper (e.g. cotton-based cartridge paper), or any other similar material.

The packing discs 28 and 56 are in the form of unitary discs hving a central aperture through which the supporting member, 10 and 30 respectively, extends. However, it is envisaged that each of the packing discs 28 and 56 may be replaced by two, separate packing discs which are disposed concentrically on the supporting member 10 and 30 respectively such that, with regard to the pulley shown in Figure 1 for example, a first packing disc extends between the surface 22 of the clamping ring 19 and the side 18 of the annulus 12, and a second packing disc extends between the surface 22 of the clamping ring 19 and the surface 27 of the supporting member 10. It will be appreciated that the two packing discs will be substantially of the same thickness and of the same material.

Furthermore, by replacing each of the packing discs 28 and 56 with two separate packing discs. the surface 27 for example, may be displaced axially of the support member 10 such that the side 18 of the annulus 12 and the surface 27 remain parallel to one another but are no longer substantially in the same plane. In such a case, a corresponding displacement is made to the portion of the surface 22 of the clamping ring 19 which lies adjacent to the surface 27.

Each of the ceramic annuli described with reference to the pulleys shown in Figures 1 and 2 may have its four corners chamfered so as to reduce the possibility of unduly high stresses occuring at those corners.

Drive may be transmitted from the supporting member to the ceramic annuli by friction alone. However. this may not be sufficient in some cases. especially when the pulley is being operated at high temperatures. and it is preferable therefor to provide for each of the ceramic annuli, an additional drive transmitting means in the form of a pin which projects radially out of the supporting member into a slot in a respective ceramic annulus.

WHAT WE CLAIM IS: 1. A wire-drawing pulley comprising supporting means to be rotated about an axis. and a ceramic annulus which is coaxially mounted on the supporting means by a clamping member for rotation with the supporting means and the clamping member about the said rotational axis, wherein the clamping member overlies a side of the ceramic annulus and is clamped to a surface of the supporting means to mount the ceramic annulus on the supporting means, and wherein deformable means is deformably mounted between the clamping member and the ceramic annulus, and between the clamping member and the said surface of the supporting means.

2. A wire-drawing pulley according to Claim 1, wherein the deformable means is resilient.

3. A wire-drawing pulley according to Claim 1 or Claim 2, wherein the deformable means is a unitary member.

4. A wire-drawing pulley according to Claim 3, wherein the deformable means is in the form of a disc.

5. A wire-drawing pulley according to any one of the preceding claims, wherein the deformable means is of neoprene-coated nylon.

6. A wire-drawing pulley according to any one of Claims 1 to 4, wherein the deformable means is of nitrile rubber.

7. A wire-drawing pulley according to any one of Claims 1 to 4, wherein the deformable means is of paper.

8. A wire-drawing pulley according to any one of the preceding claims, wherein the clamping member completely overlies the said side of the ceramic annulus.

9. A wire-drawing pulley according to Claim 8, wherein the deformable means completely overlies the said side of the ceramic annulus.

10. A wire-drawing pulley according to any one of the preceding claims, wherein the said surface of the supporting means extends substantially transversely of said rotational axis.

11. A wire-drawing pulley according to any one of the preceding claims, wherein the clamping member includes a flange which engages with the outer peripheral surface of the ceramic annulus to maintain the annulus substantially coaxial on the supporting means.

12. A wire-drawing pulley according to any one of the preceding claims, wherein the supporting means includes a part which extends substantially transversely of said rotational axis and which overlies the other side of said ceramic annulus.

13. A wire-drawing pulley according to Claim 12, wherein further deformable means is deformably mounted between said other side of the ceramic annulus and the said part.

14. A wire-drawing pulley acording to Claim 12 or Claim 13. wherein the said part includes a flange which engages with the outer peripheral surface of the ceramic

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. pulley. A thin, deformable washer 57 of, for example, cotton-based cartridge paper, is disposed between the ceramic annuli 33, 34, 35 and 36 and the clamping rings 38, 39, 40 and 41 respectively to improve clamping. The deformable packing discs 28 and 56 described with reference to Figures 1 and 2 respectively of the drawings. may, alternatively, be of nitrile rubber, cartridge paper (e.g. cotton-based cartridge paper), or any other similar material. The packing discs 28 and 56 are in the form of unitary discs hving a central aperture through which the supporting member, 10 and 30 respectively, extends. However, it is envisaged that each of the packing discs 28 and 56 may be replaced by two, separate packing discs which are disposed concentrically on the supporting member 10 and 30 respectively such that, with regard to the pulley shown in Figure 1 for example, a first packing disc extends between the surface 22 of the clamping ring 19 and the side 18 of the annulus 12, and a second packing disc extends between the surface 22 of the clamping ring 19 and the surface 27 of the supporting member 10. It will be appreciated that the two packing discs will be substantially of the same thickness and of the same material. Furthermore, by replacing each of the packing discs 28 and 56 with two separate packing discs. the surface 27 for example, may be displaced axially of the support member 10 such that the side 18 of the annulus 12 and the surface 27 remain parallel to one another but are no longer substantially in the same plane. In such a case, a corresponding displacement is made to the portion of the surface 22 of the clamping ring 19 which lies adjacent to the surface 27. Each of the ceramic annuli described with reference to the pulleys shown in Figures 1 and 2 may have its four corners chamfered so as to reduce the possibility of unduly high stresses occuring at those corners. Drive may be transmitted from the supporting member to the ceramic annuli by friction alone. However. this may not be sufficient in some cases. especially when the pulley is being operated at high temperatures. and it is preferable therefor to provide for each of the ceramic annuli, an additional drive transmitting means in the form of a pin which projects radially out of the supporting member into a slot in a respective ceramic annulus. WHAT WE CLAIM IS:

1. A wire-drawing pulley comprising supporting means to be rotated about an axis. and a ceramic annulus which is coaxially mounted on the supporting means by a clamping member for rotation with the supporting means and the clamping member about the said rotational axis, wherein the clamping member overlies a side of the ceramic annulus and is clamped to a surface of the supporting means to mount the ceramic annulus on the supporting means, and wherein deformable means is deformably mounted between the clamping member and the ceramic annulus, and between the clamping member and the said surface of the supporting means.

annulus to maintain the annulus substantially coaxial on the supporting means.

15. A wire-drawing pulley according to any one of the preceding claims, wherein an annular gap is provided between the inner peripheral surface of the ceramic annulus and the supporting means.

16. A wire-drawing pulley according to any one of the preceding claims, wherein the pulley comprises a plurality of ceramic annuli mounted coaxially on the supporting means in echelon for rotation with said supporting means about said rotational axis.

17. A wire-drawing pulley according to Claim 16, wherein each of at least two of the ceramic annuli is clamped between a pair of clamping members mounted on the supporting means with one of the clamping members overlying one side of the annulus while the other clamping member overlies the other side of the annulus and is clamped to a surface of the supporting means to mount the annulus thereon, there being deformable means deformably mounted between the said other clamping member and both the said other side of the annulus and the said surface of the supporting means.

18. A wire-drawing pulley according to any one of the preceding claims, wherein the said supporting means is tubular.

19. A wire-drawing pulley according to Claim 18, wherein the bore of said supporting means is adapted to receive a drive shaft for rotating the supporting means.

20. A wire-drawing pulley substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

21. A wire-drawing pulley substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.