AU599718B2

AU599718B2 - Adjustable pulley sheave

Info

Publication number: AU599718B2
Application number: AU81227/87A
Authority: AU
Inventors: Peter Sydney Wright
Original assignee: FF Seeley Nominees Pty Ltd
Current assignee: FF Seeley Nominees Pty Ltd
Priority date: 1986-11-13
Filing date: 1986-11-13
Publication date: 1990-07-26
Anticipated expiration: 2007-11-13
Also published as: AU8122787A

Description

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Form COMMON( v/if'i//I//IllhllIN

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PAThN rS COMPLETE SPECIFICATION

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FOR OFFICE USE: Class Int. Class Application Number: Lodged: o o Comrplet Specification Lodged: Accepted: o Published: Pri i d ty:: 11 1 I 6? lo ps I U Ipa 1;'PUW 1 'MIarr larpr~ Related Art:

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a ie of Applicant: Address of Applicant: Actual Inventor: Address for Service: TO BE COMPLETED BY APPLICANT F.F. SEELEY NOMINEES PTY. LTD., a company incorporated under the laws of the State of South Australia, 3 Rothesay Avenue, St. Marys, State of South Australia, Commonwealth of Australia.

PETER SYDNEY WRIGHT R.K. MADDERN ASSOCIATES, 345 King William Street, Adelaide, State of South Australia, Commonwealth of Australia.

Complete Specification for the invention entitled: "ADJUSTABLE PULLEY SHEAVE" The following statement Is a full description of this invention, Including the best method of performing it known toXe. us.

i This invention relates to a pulley sheave of the type wherein adjustment is achieved by screwing a flank member onto the boss of a base member.

Pulley sheaves of the type disclosed above are in common use, and are valuable in that a single sheave formed from a base member and a flank member can have the flank member moved towards or away from the base member to thereby vary the effective pitch diameter of 00 S0o the sheave. The sheave is intended for use with a V-belt, 0 00 0.10o: or a belt having a circular cross-sectional shape.

o oo It is obviously desirable to inhibit dislodgement 0000..

once the selected pitch diameter has been adjusted, and in order to achieve this the usual arrangement is for the base member to have a pair of opposite flat surfaces, o and for the skirt of the flank member to contain a o o threaded aperture which is engaged by a grub screw which 0:0.0 bears against a flat surface to thereby inhibit rotation.

oo~a 0:0 ~In some instances the flank member threadably engages 0 the base member, and by this means it is possible to 00 o.200 achieve adjustment by half turn increments of the screw thread, because there are two flats. Some problems however exist with such an arrangement.

Firstly, upon assembly, adjustment is slow and tedious i since the grub screw must be released and tightened each time adjustment is varied. Secondly, a grub screw is notorious for damaging the surface of the metal which it -2engages. Thirdly, there are not very many plastics having sufficient strength in shear and tension to accept a thread the grub screw is tightened to the normal degree of torque.

The main objects of this invention are to provide improvements whereby plastics may be used, the adjustment may be achieved quickly and easily, and yet the locking can be at least as effective as a grub screw but is o 0 unlikely to cause damage to surfaces.

0 0 °0o0 In an embodiment of this invention, an adjustable 0o 0o pulley sheave comprises a base member, a flank member oo0 and a locking ring, the base member comprising a boss o 0 o 0 having thereon a male thread, a plurality of abutment surfaces and a belt engagement flange projecting away i 00 from one end of its said boss both in a radial and in 0 00 o° a first axial direction, the flank member also comprising o 0 a boss, said boss containing a female thread threadably S° engaging said male thread, and a belt engagement flange 0 o0o projecting from one end of its said boss radially and 0 0 o 204 in a second axial direction opposite said first, the locking ring being non-rotatable but slidable over the base member boss in both axial directions, but having 4 means thereon so engageable against the abutment surfaces that said slidable movement is restrained but not prevented, the locking ring also having surfaces thereon which so engage complementary surfaces of the flank member as to prevent relative rotation, but can disengage those surfaces upon sliding movement of the locking ring in said second axial direction.

An embodiment of the invention is described hereunder in some detail with reference to and is illustrated in the accompanying drawings in which: Fig. 1 is an "exploded" section which illustrates a base member, a flank member and a locking ring; 0° Fig. 2 is an end elevation of the flank member of 70 the sheave; and 0> %o Fig. 3 is an end elevation of a lock ring.

00.o0 S° The base member 10 comprises a boss 11 having a o male thread 12 surrounding it, and two opposite parallel flat portions 13. The boss 11 is provided with a plurality o0o

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1 5 of abutment surfaces, and while use could be made of 0 00« surfaces of the male thread 12, in this embodiment each flat portion 13 has a plurality of upstanding teeth 14 which are not of ratchet shape, but have a curved profile.

The boss 11 has a belt engagement flange 15 which diverges o..~i6o away from one end, projecting away both in a radial and a first axial direction (to the right as shown).

The flank member 18 is provided with a boss 19 having an internal thread 20 which will threadably engage the thread 12 of the base member 10. The outer surface of the boss is provided with a plurality of circumferentially spaced recesses 2i at one end of the boss 19 and at the -4other end there is provided a second belt flange 22 which, upon assembly, diverges radially outwardly from the belt flange that is, projects from the right hand end of its boss 19 both radially and axially in a second axial direction (to the left as illustrated).

The third member of the assembly is a lock ring illustrated in Fig. 3 and this has a flange 26 which extends radially inwardly, and a series of projections 27 which extend axially away from the flange 26 and are co-operable with the surfaces of recesses 21 to inhibit relative rotation between lock ring 25 and flank member 18. The shapes and sizes of projections 27 are co-ipler'entary to the shapes and sizes of recesses 21 so that they key into recesses 21 when lock ring oo 0:0 is moved axially to engage flank member 18.

To ensure locking between the base member 10 and the flank member 18, the inner surface of flange 26 comprises two flat 0 0 0o,°°o portions 28 which are complementary to the flat portions 13 of o oo the base member 10, and to restrain the lock ring 25 from dislodgement in an axial direction, the centre of each flat o portion 28 contains a recess 29 which has an inwardly directed 0 oo tongue 30, the tongues riding over the teeth 14 to restrain the o o lock ring from axial movement, but the lock ring can be pushed on or pulled off the boss 19 upon resilient deformation of the tongues 30.

o 00 I 0 0 0 The invention provides means for very rapid assembly, or j disassembly of the pulley sheave, and adjustment is easily and quickly effected. Since the locking means A4 6d does not include screw threaded members, a suitable plastics material can be used, for example glass filled nylon.

0 0 00 0 0 00

Claims

1. An adjustable pulley sheave which comprises a base member, a flank member and a lock ring, the base member comprising a boss having thereon a male thread, a plurality of abutment surfaces and a belt engagement flange projecting away from one end of its said boss both in a radial and in 2 first axial direction, the flank member also comprising a boss, said boss containing a female thread threadably engaging said male thread, and a belt engagement flange projecting from one end of its said boss radially and in a second axial direction opposite said first, the lock ring being non-rotatable but slidable over the base member boss in both axial directions, but having means thereon so engageable against the abutment surfaces that said slidable movement is restrained but not prevtited, the lock ring also having surfaces thereon which so engage complementary o 0' surfaces of the flank member as to inhibit relative rotation between the lock ring and flank member when the lock ring engages the flank member. 0

2. An adjustable pulley sheave according to claim 1 wherein said abutment surfaces are the surfaces of teeth on the base member boss, and said engageable means on the lock ring are resilient tongues of the lock ring which, upon said slidable movement, engage but ride over the teeth.

3. An adjustable pulley sheave according to claim 2 wherein 46 said teeth lie in or on otherwise flat portions on said base member, and said lock ring also has flat portions which slidably but non-rotationally engage the base member flat portions.

4. An adjustable pulley sheave according to any preceding claim wherein said lock ring surfaces comprise surfaces of projections, and said flank member surfaces comprise surfaces of recesses which are engaged by those said projection surfaces L J upon said sliding movement of the lock ring in said first axial direction. An adjustable pulley sheave substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. DATED this 8th day of May 1990 F F SEELEY NOMINEES PTY LTD By its Patent Attorneys R K MADDERN ASSOCIATES 00 0 000 o o 0 0 0 0 0 0 0 00 0 0 do o 0 0 S00 o 0 ooo a 0 4 LS -8- V> f^-8-