SHAFT ENGAGING ASSEMBLY

Abstract: The assembly comprises a moulded lower part (10) having an arcuate wall (12) and an upper part (11) having an arcuate wall (13). In use, the arcuate walls cooperate to engage a cylindrical surface of a shaft to provide a bearing, clutch or a brake for that shaft.

Description: SHAFT ENGAGING ASSEMBLY The present invention relates to a shaft engaging assembly and to such an assembly when engaging a shaft. The assembly may be a bearing, clutch or brake assembly. The present invention will now be defined with reference to upper and lower parts. However, it will be appreciated that the present invention is applicable to those parts when the parts are reversed such that the upper part becomes the lower part and vice versa and also in the arrangement where the parts are opposed to each other in any relative orientation. According to one aspect of the present invention a shaft engaging assembly comprises a lower part and an upper part, each part including an arcuate surface arranged, in use, to engage a shaft, each part including connection portions at opposed side regions, the connection portions being arranged to connect the parts to each other to cause the arcuate surfaces to engage a shaft, at least one of the parts including strengthening means extending downwardly from each connection portion towards each other. The strengthening means may extend to a location above the bottom of the shaft, above a tangent to the shaft at the side region that the strengthening means extend from or below the elongate axis of a shaft. The connection portions of each part may be arranged to face each other at a location above the elongate axis of the shaft and that location may be substantially at the same elevation as the top of the shaft. The connection portions may be arranged to urge the parts towards each other to thereby cause the arcuate surfaces to more. firmly engage a shaft. The connection portions of the upper and lower parts may be arranged to be spaced from each other when the parts are connected. Alternatively, the connection portions may be arranged to contact each other when the parts are connected. At least one of the parts may be arranged to be flexed when the parts are connected, for instance against a resilient force. Each strengthening means may be arranged to engage a shaft . The strengthening means of at least one part may comprise a pair of spaced strengthening means at each axial end region of the part. The connection portions of one part may be arranged to be received, in an axial direction, between the pair of spaced strengthening means at each side region of the other part . At least one part may include a web, the plain of which extends in a generally axial direction with the strengthening means comprising a web, the plane of which extends in a generally radial direction. The connection portions may comprise a portion that extends generally transverse to the plane of the two webs of the strengthening means. The web of the lower portion may include means to attach the assembly to a machine, and those means may comprise one or more slots or openings. Both the upper and lower parts may have any of the features referred to above. The upper and lower parts may include strengthening means that are axially aligned with each other. The strengthening means may be spaced from each other. The strengthening means of the facing upper and lower parts may be at substantially the same angle. The extent of the arcuate surface of the lower part may be less than the extent of the arcuate surface of the upper part . The axial extent of the lower part may be slightly less than 180° and the arcuate extent of the upper part may be in the region of 90°. At least one of the parts can be formed by moulding, such as by injection moulding. The upper part may have an arcuate surface having a greater frictional resistance than the frictional resistance of the lower part. The assembly may include a threaded member arranged to engage the lower part and arranged to bear against the upper part to urge those parts towards each other. Threaded members may be provided at both sides of the assembly. At least one of the parts may include an abutment in which a shaft is arranged to cooperate with to restrict relative axial movement of the shaft and the assembly in one axial direction. The present invention also includes an assembly when engaging a shaft. The assembly may comprise a bearing assembly, a clutch assembly or a brake assembly. The present invention includes any combination of the herein referred to features or limitations. The present invention may be put into practice in various ways but one embodiment will now be described, by way of example, and with reference to the accompanying drawings in which: - Figure 1 is a schematic perspective view of a lower part of a bearing, brake or clutch assembly; Figure 2 is a view similar to Figure 1 of an upper part of a bearing brake or clutch assembly; and Figure 3 is a radial cross-sectional view through the mid points of the upper and lower parts of the clutch assembly when in their cooperating position. As shown in the figures, the integrally moulded lower part 10 and upper part 11 have respective arcuate walls 12 and 13 (shown schematically in Figures 1 and 2 as being a series of flats but which are in practice arcuate) that are arranged to engage the cylindrical surface of a shaft (not shown) to provide a bearing, clutch or a brake therefor. Each arcuate wall is of less than 180° in extent with the lower wall extending through just less than 180° and the upper wall extending through approximately 90°. The shaft can extend through the assembly, without the assembly having any axial restraint on the location of the shaft. Alternatively one or both parts may have an end wall 14, such as that shown on the upper part 11 to restrict movement of the shaft through the assembly in one axial direction. As shown in Figure 3, the thickness of the central region of the parts that define the arcuate walls 12 and 13 is relatively thin and may, for instance, be of the order of 1.5 or 2 mm thick. In the central region of the parts, the lower part terminates at each side in outwardly extending flanges 15 the lower edge 16 of which is generally at the same elevation as the highest point of the arcuate wall 13. The flanges 15 each have a downwardly extending opening 17 which may, optionally, be threaded. In the central region of the upper part 11, relatively thin walls 18 extend upwardly from each side of the arcuate wall 13 which each terminate in an outwardly extending flange 19 at their upper end. Each flange 19 includes a countersunk, downwardly extending opening 20 therethrough. Upper and lower parts 10 and 11 are connected together, or urged towards each other by a fastening means that may comprise threaded bolts (not shown) located in the countersunk openings 20 cooperating with- the threaded walls of the lower openings 17 or with nuts located beneath the lower openings. The adjacent surfaces of the upper and lower flanges 19 and 15 shown in Figure 3 remain spaced from each other. In an alternative embodiment (not shown) the flanges abut each other. In both embodiments, the upper part and the lower part or both may flex, against the resilience of the parts, when the parts are connected. If only the mid section so far described were present, with the relatively thin walls, then a shaft engaged by the parts would not have an even grip exerted on its circumference. That is because the flanges of the lower part would tend to be drawn towards each other to wrap the lower arcuate section around the shaft. That would result in the sides of the arcuate wall 12 gripping the shaft too tightly thereby subjecting those parts of the assembly to undue wear. Furthermore, flexure of the assembly may result in fatigue or breakage of the assembly. Similarly each side of the arcuate wall 13 will tend to be brought in causing undue wear of those side portions and unwanted flexure. In order to assist in reducing any flexure that may tend to occur, and in order to keep the forces exerted on the flanges 15 and 19 in a substantially linear vertical direction and in order to reduce bending movements of those flanges about their connection to the walls 12 and 13 the upper and lower parts are provided with end walls. As shown in Figure 1, the end walls 21 form part of the wall 12 against which a shaft will bear. Each wall is connected to the outer portion of the flanges 15 with end wall having a flat lower side 22. The lower sides 22 shown in Figure 2 include slots 23 therein which assist in the mounting of the lower part 10 on edges of a machine, for instance, which can extend through aligned slots 23. In the embodiment shown in Figure 3, openings 23 are provided that allow fasteners to be passed through to secure the part to a mounting. Each wall also extends from its connection to the flange 15 downwardly and inwardly to define a slanting upper region 24. When the parts are assembled, the bolt will exert a force on the flange in an upwards direction. That force will tend to cause the flanges to bend inwardly towards each other. The regions 24 of the walls transmit or resist the force tending to cause such movement from the flanges to the arcuate extent of the shaft at each side of the base of the shaft generally in line with angle of the regions 24. Thus a generally linear force is exerted on the flanges and the bolt and a generally even force is applied to the arcuate extent of the shaft. Each end region 24 is angled such that, when extrapolated, they would meet at a point just below the centre of a shaft. The end walls 25 of the upper part are similar to the walls 21 in that they extend across the top of the part from one side to the other and that they connect each flange. Each end wall 25 is integrally formed such that it is completely coextensive with the flange 19 (the end wall 21 in Figure 1 includes a small gap 26 between the flange 15 and the end wall at an inner region thereof) . The end walls 25 also form part of the arcuate surface that will engage a shaft and thus they are coextensive with the wall 13 in that region. The end walls 25 include, at each side, downwardly and inwardly inclined regions 27 that extend towards a shaft and, when extrapolated, their angle is such that they would meet slightly below the axis of such a shaft. When the parts are connected a force tending to cause bending of the flanges downwardly would be at least partially resisted by that force being transmitted through the inclined regions to the shaft thereby ensuring a generally even grip of the wall 13 with the shaft around and along their co-extent. The axial spacing of the end walls 25 of the upper part allows the flanges 15 of the lower part to be received therein in order to ensure that the openings in the upper and lower flanges are aligned and in order to assist in the axial location of the upper part relating to the lower part . Each part may be of plastics and may be moulded such as injection moulded and may be of nylon or acetal . As the wall thickness of each part (be that the axially extending walls or the radially extending walls) in relatively thin, a relatively small amount of plastics is required to provide an arrangement that is strong and that provides an even grip on a shaft . The primary purpose of the arrangement is as a bearing, in which case both the upper and lower parts will be of low friction material, at least in the region where they engage the shaft . By altering the material of the upper part, or at least the material where the upper part engages a shaft, to be of a higher friction material, the bearing assembly can act as a brake or a clutch, in which case the forces applied between the flanges can be varied in dependence upon the braking or release effect required. The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims: CLAIMS 1. A shaft engaging assembly comprising a lower part and an upper part, each part including an arcuate surface arranged, in use, to engage a shaft, each part including connection portions at opposed side regions, the connection portions being arranged to connect the parts to each other to cause the arcuate surfaces to engage a shaft, at least one of the parts including strengthening means extending downwardly from each connection portion towards each other. 2. An assembly as claimed in Claim 1 in which the strengthening means extends to a location above the bottom of the shaft. 3. An assembly as claimed in Claim 1 or 2 in which the strengthening means extends to a location above a tangent to the shaft at the side region that the strengthening means extend from. 4. An assembly as claimed in any of Claims 1 to 3 in which the strengthening means extends to a location below the elongate axis of a shaft. 5. An assembly as claimed in any preceding claim in which the connection portions of each part are arranged to face each other at a location above the elongate axis of the shaft . 6. An assembly as claimed in any of Claims 1 to 4 in which the connection portions of each part face each other at a location substantially at the same elevation as the top of the shaft . 7. An assembly as claimed in any preceding claim in which the connection portions are arranged to urge the parts towards each other to thereby cause the arcuate surfaces to more firmly engage a shaft. 8. An assembly as claimed in any preceding claim in which the connection portions of the upper and lower parts are arranged to be spaced from each other when the parts are connected. 9. An assembly as claimed in any of Claims 1 to 7 in which the connection portions are arranged to contact each other when the parts are connected. 10. An assembly as claimed in any preceding claim in which at least one of the parts is arranged to be flexed when the parts are connected. 11. An assembly as claimed in Claim 10 in which one of the parts is arranged to be flexed against a resilient force when the parts are connected. 12. An assembly as claimed in any preceding claim, in which each strengthening means is arranged to engage a shaft. 13. An assembly as claimed in any preceding claim in which the strengthening means of at least one part comprises a pair of spaced strengthening means at each axial end region of the part. 14. An assembly as claimed in any preceding claim in which the connection portions of one part are arranged to be received, in an axial direction, between a pair of spaced strengthening means at each side region of the other part . 15. An assembly as claimed in any preceding claim in which at least one part includes a web, the plain of which extends in a generally axial direction with the strengthening means comprising a web, the plane of which extends in a generally radial direction. 16. An assembly as claimed in Claim 15 in which the connection portions comprise portions that extend generally transverse to the plane of the two webs. 17. An assembly as claimed in either of Claims 15 or 16 in which the webs are on the lower portion and the web of the lower portion that extends in a generally radial direction includes means to attach the assembly to a machine. 18. An assembly as claimed in Claim 17 in which the means to attach the assembly to a machine comprises one or more slots or openings. 19. An assembly as claimed in any preceding claim in which both the upper and lower parts have any of the features referred to above. 20. An assembly as claimed in any preceding claim in which the upper and lower parts may include strengthening means that are axially aligned with each other. 21. An assembly as claimed in Claim 20 in which the strengthening means are spaced from each other. 22. An assembly as claimed in Claim 20 or 21 in which the strengthening means of the facing upper and lower parts are at substantially the same angle. 23. An assembly as claimed in any preceding claim in which the extent of the arcuate surface of the lower part is less than the extent of the arcuate surface of the upper part . 24. An assembly as claimed in Claim 23 in which the axial extent of the lower part is slightly less than 180° and the arcuate extent of the upper part is in the region of 90°. 25. An assembly as claimed in any preceding claim in which at least one of the parts is formed by moulding. 26. An assembly as claimed in Claim 25 in which at least one of the parts is formed by injection moulding. 27. An assembly as claimed in any preceding claim in which the upper part has an arcuate surface having a greater frictional resistance than the frictional resistance of the lower part. 28. An assembly as claimed in any preceding claim in which the assembly includes a threaded member arranged to engage the lower part and arranged to bear against the upper part to urge those parts towards each other. 29. An assembly as claimed in Claim 28 in which the threaded members are provided at both sides of the assembly. 30. An assembly as claimed in any preceding claim in which at least one of the parts includes an abutment in which a shaft is arranged to cooperate with to restrict relative axial movement of the shaft and the assembly in one axial direction. 31. A shaft engaging assembly substantially as herein described with reference to, and as shown in any of Figures 1 to 3. 32. A shaft engaging assembly as claimed in any of Claims 1 to 31 when engaging a shaft. 33. A shaft engaging assembly as claimed in any preceding claim comprising a bearing assembly. 34. A shaft engaging assembly as claimed in any preceding claim comprising a clutch assembly. 35. A shaft engaging assembly as claimed in any preceding claim comprising a brake assembly.

Inventors: O'CONNOR STEPHEN TERENCE, O'CONNOR, STEPHEN, TERENCE
Applicants: CONNOR STEPHEN TERENCE O, HEIGHTS DESIGN PRODUCTION LIMI, HEIGHTS DESIGN PRODUCTION LIMITED, O'CONNOR, STEPHEN, TERENCE
Application year: 1998
Main classification: F16C35
IPC codes: F16C35