PROTECTIVE GAITERS FOR JOINTS

Abstract: A protective gaiter fits around a lubricated joint, such as a motor vehicle constant velocity joint. The gaiter has a tubular body (10) with a central flexible, folded part (18) and stepped end parts (11, 12) with channels (13, 14) for clamping devices. Folds (20, 21) are provided in the end parts (11, 12) between the channels (13, 14) so that the end parts (11, 12) as well as the central part (18) are flexible.

Description: This invention relates to protective gaiters for joints particularly although not exclusively for use in motor vehicles. Flexible rubber gaiters are used in motor cars to protect constant velocity joints so as to prevent ingress of dirt and moisture and egress of lubricants. These gaiters customarily comprise moulded tubes having cylindrical end portions suitably diametered to fit the pertaining joint members and a flexible convoluted central portion. GB-A-2156452 discloses a moulded rubber gaiter of this kind further having end portions adapted by the provision of multiple fitting sections of different diameters allowing attachment to a number of different dimensions of joint members. This provides a versatile gaiter in so far as it can be used with constant velocity joints of different motor car models by appropriate cutting away of the fitting sections. The requisite flexibility of the gaiter is derived essentially from the central portion which may be a bellows type construction and the end portions are of limited flexibility. Whilst generally satisfactory, since the end portions can represent significant parts of the length of the gaiter, limitations in the flexibility of such portions can impose limitations on the overall flexibility of the gaiter. DE-A-3324997 also discloses a gaiter with multiple fitting sections of different diameters. However, flat seating channels are shown which would impose limitations on flexibility. An object of the present invention is to eliminate or at least minimise such limitations. According to the invention therefore there is provided a protective gaiter to fit around a lubricated joint between joint members, said gaiter comprising a generally frusto-conical flexible tubular body having first and second ends with inner and outer surfaces thereto and a central portion between said ends. Said first end being wider than said second end, both said ends having axially spaced annular fitting sections incorporating annular seating channels around said outer surfaces to receive fixing devices whereby the said inner surfaces can be clamped into sealing engagement respectively with said joint members thereby to seal said lubricated joints, said central portion having first folds therein so as to permit axial extension of the body, said fitting sections being defined by stepped configurations, and said wider end having second folds between the seating channels, characterised in that said seating channels of said fitting sections at said wider end are curved in cross-section along the axis of the gaiter, the central part of each curved fitting portion being closer to the axis of the gaiter than the ends of each fitting portion, said second folds extending away from the axis of the gaiter, said gaiter being configured to permit axial flexing. With this arrangement the overall flexibility of the gaiter can be improved. Said tubular body may be conically tapered and stepped and may be of uniform thickness around the entire circumferential periphery thereof. Said body may be of uniform thickness throughout the whole length or at least a substantial part thereof. Preferably said channels at the or each end of the body are uniformly spaced with said folds therebetween. Said central portion may be of a bellow-like configuration or may be formed as an S-bend or U-bend or the like. The steps of said body may be flat or curved or any other suitable configuration as appropriate. Furthermore preferably said central portion extends substantially over half the length of the tubular body. In one embodiment the inner surface of each section is at least generally parallel to the gaiter axis. Each fitting section may be appropriately configured on its inner surface for co-operation with a sealing configuration on the pertaining joint member. Thus each fitting section may have one or more circumferential ribs for co-operation with a sealing groove or grooves. Each fitting secton is appropriately configured on its outer surface by provision of a channel thereon to receive a fixing device such as a circlip or the like. The gaiter may be moulded in one piece from any suitable natural or synthetic rubber material. The invention will now be described further by way of example only and with reference to the accompanying drawings of which:- Figure 1 is a sectional side view of one form of gaiter according to the invention; and Figure 2 is a view to a larger scale of a detail of the gaiter of Figure 1. The gaiter of Figures 1 and 2 comprises a one-piece moulded rubber tube generally of frusto-conical form. The end portions 11, 12 of the tube are each stepped to define a number of annular fitting sections 13, 14 of progressively increasing diameter which extend parallel to the tube axis 15. At the wider end of the tube 10 there are four such sections 13 increasing in diameter towards the pertaining free end. At the narrower end there are three such sections 14 decreasing in diameter towards the pertaining free end. The end portions 11, 12 are suitably configured and adapted such that a relatively large amount of flexibility is permitted therein both transversely of and parallel to the tube axis 15. On its outer surface each section 13 has a curved central annular surface having at one end a groove 16 and upstanding rib 17. Each section 14 is bounded at each end thereof by an upstanding rib. Thus the outer surfaces of the end portions 11, 12 are convoluted defining multiple folds 20, 21 which not only allow axial flexibility but can also conveniently accommodate suitably configured projecting lips on the joint members. The central portion 18 of the gaiter is formed into multiple convolutions 19 which allow such section to flex and also to extend axially. With the gaiter formed as above it will be appreciated that such gaiter is readily flexible along the entire length of the tubular body and not solely in the region of the central portion 18 thereof. This has enormous advantages, not the least of which is the allowability of less restricted relative movement between the joint members protected in this way. In use the gaiter is fitted around a joint (such as a motor car constant velocity joint) and is secured in position (after filling with a suitable lubricant) by clamping one of the sections 13 at the wider end around one joint member and one of the sections 14 at the narrower end around the other joint member. Sections 13, 14, which are outwardly of the sections which are clamped in position may be cut away at respective ones of the positions identified by letters A-E on the drawing. The sections 13, 14 are clamped in position by circlips or the like around the outer surfaces of the sections. The inner surface of the end portions 11, 12 can be suitably adapted in order to provide an efficient seal around the joint member. The length of the gaiter is adjusted as required by extension or contraction of the entire gaiter and in this respect the gaiter is manufactured so as to be capable of such deformation. With this arrangement, it will be appreciated that the gaiter can be readily adapted to fit a range of joints. The need to manufacture and stock a wide range of gaiters to fit different joints can therefore be avoided or at least minimised. Furthermore, due to the gaiter being flexible along its entire length, it is readily deformable and thus can conveniently be arranged to any length as desired in such a manner that the flexibility of the gaiter remains constant irrespective of the length thereof. In the preferred form of the invention, and as shown in the accompanying drawings, the gaiter has a central portion 18 with main convolutions 19 and two end portions 11, 12 with supplementary convolutions 20, 21. The main convolutions 19 are provided exclusively in the central portion and are larger (of greater peak-to-peak displacement) and of greater axial extensibility than the supplementary convolutions. The supplementary convolutions are exclusively in the respective end portions of the gaiter and are smaller and of smaller axial extensibility. In addition to promoting flexibility, the configuration of the end portions, as mentioned, facilitates fitting over flanges having upstanding lips or the like.

Claims: A protective gaiter to fit around a lubricated joint between joint members, said gaiter comprising a generally frusto-conical flexible tubular body having first and second ends (11, 12) with inner and outer surfaces thereto and a central portion (18) between said ends. Said first end (11) being wider than said second end (12), both said ends having axially spaced annular fitting sections (13, 14) incorporating annular seating channels around said outer surfaces to receive fixing devices whereby the said inner surfaces can be clamped into sealing engagement respectively with said joint members thereby to seal said lubricated joints, said central portion (18) having first folds (19) therein so as to permit axial extension of the body, said fitting sections (13, 14) being defined by stepped configurations, and said wider end (11) having second folds between the seating channels, characterised in that said seating channels of said fitting sections (13) at said wider end (11) are curved in cross-section along the axis of the gaiter, the central part of each curved fitting portion being closer to the axis of the gaiter than the ends of each fitting portion, said second folds extending away from the axis of the gaiter, said gaiter being configured to permit axial flexing. A protective gaiter according to claim 1 characterised in that said tubular body is of uniform thickness around the entire circumferential periphery thereof. A protective gaiter according to claim 1 or 2 characterised in that said tubular body is of uniform thickness throughout at least a substantial part of the whole length thereof. A protective gaiter according to any one of claims 1 to 3 characterised in that said channels of said fitting sections (13) are uniformly spaced with said second folds therebetween. A protective gaiter according to claim 4 characterised in that there is a single said second fold between each pair of adjacent said seating channels. A protective gaiter according to any one of claims 1 to 5 characterised in that the said central portion (18) extends substantially over half the length of the tubular body. A protective gaiter according to any one of claims 1 to 6 characterised in that the inner surface of each section (13, 14) is generally parallel to the gaiter axis. A protective gaiter according to any one of claims 1 to 7 characterised in that each fitting section (13, 14) has one or more circumferential ribs for cooperation with a sealing groove or grooves.

Inventors: PHILIP FIELDS HAYWARD
Applicants: PHILIP FIELDS HAYWARD
Application year: 1990
Main classification: F16J3
IPC codes: F16D3, F16J3