Description of Invention

This invention is concerned with improvements relating to clamping devices, particularly but not exclusively for use in the provision of a windscreen wiper assembly.

A splined clamping device is utilised where it is desired releasably to connect a mechanism to a shaft for instrumentalities of the device to be moved by movement of the shaft. Conventionally the device comprises a housing provided with an internally splined bore and the spindle is provided with exterior splines capable of interfitting within the bore. Conventionally the housing is split or provided with a slot, the slot extending from the bore and opening into the exterior of the housing, and means, conventionally screw-threaded means, is provided for closing the slot and causing the bore to be tightened around the splined shaft, to bring the splines into driving engagement.

According to a first aspect of this invention there is provided a splined clamping device comprising a housing having a splined bore, a slot extending from the bore, screw-threaded means being provided for closing the slot, wherein the slot extends from the bore on the side of the housing on which the instrumentalities are carried.

In this manner the need for the housing to project beyond the bore on the opposite side of the housing is obviated.

Preferably the slot does not project to an exterior surface of the housing, and is preferably enclosed by wall portions of the housing on all sides. Thus preferably the slot is located wholly within the body of the housing. Preferably the screw-threaded tightening means is located between the bore and the instrumentalities, preferably passing through the slot in conventional manner.

Such a clamping device is particularly useful in the provision of a windscreen wiper assembly, in which the instrumentalities comprise a wiper arm extending from the housing, in that by reducing the size of the housing on the side

of the bore opposite to the wiper arm, the assembly may be fitted in position without interference with body parts of the vehicle on which it is mounted.

A conventional windscreen wiper assembly comprises a spindle provided with a frusto-conical portion provided with exterior splining, and a wiper body having a frusto-conical bore of a size similar to said frusto-conical portion of the spindle. Conventionally the spindle is made of steel, and the wiper body is made of aluminium, so that by forcing the wiper body onto the spindle, such as by a tightening screw, the splines of the spindle may deform the frusto-conical bore and enter into driving engagement with the body.

Particularly on large automotive vehicles such as buses, the length of the wiper arm is long, and the load acting upon the inter-engagement between the spindle and the wiper body is large. Frequently, particularly in adverse weather conditions such as snow, the load is sufficient to cause the splines on the spindle to strip out the deformations provided on the bore of the wiper body, requiring the wiper body to be re-tightened onto the spindle. Where this difficulty is encountered on a number of occasions, not only can it be dangerous, requiring the driver of the vehicle to stop to carry out the necessary adjustment, but also in due course the frusto-conical bore in the wiper body becomes oversize, requiring the wiper body to be replaced.

According to this invention there is provided a windscreen wiper assembly comprising a spindle having an end portion which is splined, a wiper body provided with an internally splined cylindrical bore which may be interfitted with the spindle, and tightening means to clamp the splined bore onto the spindle to bring the splines into driving engagement.

Preferably the tightening means is operative at a location between the spindle and the wiper body.

Preferably the wiper body is mounted on the spindle by a clamping device in accordance with the first aspect of this invention.

Difficulty is also encountered with windscreen wiper assemblies, in providing a bearing between the wiper spindle and the sleeve within which the

spindle extends. Since in conventional vehicles the wiper body is tightened onto the spindle by an axial nut, difficulty is encountered in providing for the introduction of lubricating fluid into the space between the spindle and the sleeve, particularly in a manner in which the introducing means does not extend forwardly of the forward-most plane of the windscreen wiper assembly. Conventionally therefore, bearing means for the spindle and the sleeve has been provided by a low friction plastics material such as ptfe. However in use water and dirt will be introduced into the space between the spindle and the sleeve, and this will cause extra wear to take place on the ptfe sleeve, requiring it to be replaced at regular intervals. This is unsatisfactory, particularly in that it may be dangerous if the wiper assembly seizes under adverse operating conditions, and in that replacement of the bearing requires the vehicle to be taken out of service.

According to this invention there is provided a windscreen wiper assembly comprising a spindle provided with a splined end portion, a wiper body provided with a cylindrical bore having interior splines, means for tightening the bore over the spindle to bring the splines into driving engagement, and means to introduce lubricating fluid into the spindle in the axial direction.

By providing the driving engagement between the spindle and the wiper body in the form of cylindrical splines, the need for a tightening nut to force the wiper body onto the spindle in the axial direction is obviated, and allows the use of a tightening means spaced from the longitudinal axis, preferably on the side thereof adjacent to the wiper arm. This permits the provision of a means, such as grease nipple, to be located on the longitudinal axis of the spindle on the outboard side thereof. This permits the use of a metallic bearing between the sleeve and the spindle, such as a bronze bearing such as "oilite".

In particular, a wiper assembly comprising a clamping device in accordance with the first aspect of the invention allows such use of a grease nipple, and the use of a metallic bearing, as described.

There will now be given a detailed description, to be read with reference to the accompanying drawings, of a windscreen wiper assembly which

is a preferred embodiment of this invention, the windscreen wiper assembly comprising a clamping device which is also illustrative of certain aspects of the invention in its own right

In the accompanying drawings

Figure 1 is a schematic view showing a conventional windscreen wiper assembly.

Figure 2 is a view showing the spindle and wiper body of the preferred embodiment, in spaced locations;

Figure 3 is an end elevation of the wiper body shown in Figure 2, taken in the direction of the arrow A, and

Figure 4 is a sectional view showing the spindle and wiper body in operative engagement

The conventional wiper assembly shown in Figure 1 comprises a steel spindle 6 mounted for rotation in a sleeve 8, cylindrical bearings 10 such as ptfe being provided between the spindle and the sleeve, the spindle and sleeve being held in axial location by a circ p 12

A portion 14 of the spindle projecting beyond the sleeve 8 is of frusto-conical form, being externally splined, and the end portion 16 of the spindle is threaded, to receive a nut 18 The wiper bodv 20 comprises a housing 22 of relatively soft material such as aluminium provided with a frusto-conical bore 24, to receive the portion 14 of the spmdle 6 By location of the bore 24 over the portion 14 and by tightening the nut 18, the housing may be driven onto the spindle 6, the splines cutting into the bore 24 to bring the spindle and housing into driving engagement

In accordance with this invention a spindle 30 is provided having a cylindπcal end portion 32 provided with splines, and the housing 40 is provided with a cylindπcal bore 42 also provided with internal splines, a slot 44 extending from the bore 42 towards the interior of the housing Screw-threaded means 44 is provided, including a screw passing through the slot 44, for closing the slot 44

and tightening the bore 42 on the splines 32, to bring the housing 40 into driving engagement with the spindle 30.

As is shown in the drawings, the slot 44 extends from the bore 42 on the interior side of the housing, and in particular on the side of the bore from which the instrumentalities, which in the preferred embodiment is in the form of a wiper arm 45, extend. In particular the slot does not open from the housing, and is bounded on all sides by wall portions of the housing.

In this manner there is no projection on the opposite side of the bore, and the underside of the housing may be provided by a smooth curved surface 46 (Figure 3).

Obviating the need for the tightening screw 18 permits an axial bore 34 to be provided in the spindle into which a grease nipple 36 may be countersunk, either being secured in position by a pressing operation or by a screw-threading operation. This permits lubricating fluid to be introduced into the space between the sleeve 8 and the spindle 30, which in turn allows the use of metallic bearings, such as the cylindrical bronze bearings 38 shown in Figure 4. In particular, as will be seen from Figure 4, the grease nipple 36 does not project forwardly of the plane B-B of the wiper body, and thus presents no protrusion which could cause injury.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.