GB2272363A

GB2272363A - Telescopic washer

Info

Publication number: GB2272363A
Application number: GB9223982A
Authority: GB
Inventors: John G Williams
Original assignee: Valeo Wiper Systems Ltd
Current assignee: Valeo Wiper Systems Ltd
Priority date: 1992-11-16
Filing date: 1992-11-16
Publication date: 1994-05-18
Anticipated expiration: 2012-11-16
Also published as: FR2698598A1; GB2272363B; DE4338639A1; GB9223982D0; FR2698598B1

Abstract

A washing device for vehicle screens comprises a cylinder (30) and a piston (35,36), movable within the cylinder (30) against the action of a spring (43), on which is mounted a nozzle carrier (32). The nozzle carrier (32) carries a nozzle assembly (34) including a valve member (33) having a lower surface (55) extending perpendicularly to the direction of fluid flow. The valve member (33) is normally held against its seat (54) by a valve spring (50), and is movable away from its seat (54) under the action of fluid pressure. The valve member (33) is held in its open position by fluid pressure on its lower surface (55). <IMAGE>

Description

2272363 1 - TELESCOPIC WASHER The present invention relates to a

telescopic washer for motor vehicle screens.

Washing systems for delivering cleaning fluid to clean headlamp screens and the like are known. They generally comprise a supply reservoir for containing the cleaning fluid, the supply reservoir being connected to a fluid delivery device which in its operative position can direct fluid onto the headlamp screen. Commonly the fluid delivery device comprises a fixed nozzle but for optimum performance it is desirable that the nozzle should be close to the headlamp screen and it is increasingly found that the styling requirements of the vehicle prevent this. In order to overcome this problem, washing systems have been proposed in which the fluid delivery device is movable between a retracted stand-by position, and an extended, operative position close to the headlamp screen. The f luid delivery device can be located in the bumper region of a vehicle, either horizontally above the bumper or vertically within the bumper itself.

A known telescopic washer comprises a cylindrical housing having an inlet for washing fluid. A nozzle carrier is mounted on a piston which is slidably mounted within the housing, and a nozzle is mounted on a distal end of the nozzle carrier which projects from the housing. The nozzle carrier is normally held in a retracted position within the housing by a return spring. When washing fluid is introduced into the housing through the inlet, the pressure of the fluid forces the piston against the return force of the return spring into an operative position in which the nozzle carrier projects from the housing. Thus, the nozzle is moved from an inoperative position, for example at the lower edge of a headlamp, to an operative position, for example perpendicularly opposite the centre of the headlamp. Thus, the nozzle does not normally obstruct the headlamp, but is located in a position of maximum washing efficiency when in use.

The nozzle carrier is an elongate tube along which washing fluid can travel to the nozzle. When the supply of washing liquid is turned on, it is important that flow through the nozzle is not permitted until the washer is fully in its operative position. Moreover, when the supply of washing fluid is turned off, the piston returns to its inoperative position under the action of the return spring and may trap fluid in the nozzle carrier.

French Patent Publication No. 2533909 discloses a telescopic washer provided with a ball valve located between the distal end of the nozzle carrier and the nozzle itself. The ball valve comprises a valve seat in which a ball is located under the action of a valve spring. The valve spring is selected in relation to the fluid pressure and the return spring so that the ball valve opens only after the nozzle carrier has reach its fully operative position. Thus, washing fluid is projected at the headlamp only from the optimum washing position.

The ball of the ball valve presents a smooth, curved surface to the fluid flow so that a relatively small surface area is presented to the fluid perpendicular to the direction of flow. This means that the f orce on the ball due to f luid pressure is comparatively small, so that for a given fluid pressure the ball must be comparatively. large, thus placing a limit on the minimum width of the valve for a given fluid pressure.

1 According to the present invention there is provided a washing device for supplying washing fluid to vehicle screens and comprising a piston mounted within a cylinder, one of the piston and cylinder being movable relative to the other against the action of biassing means, and an elongate nozzle carrier connected for movement with the movable one of the piston and cylinder and adapted to carry at one of its end regions a nozzle assembly for the delivery of washing fluid, the device including a valve assembly at said end region of the nozzle carrier, the valve assembly comprising a valve member having a lower surface extending perpendicularly to the direction of flow of washing fluid and valve biassing means for holding the valve member against a valve seat, the valve member being movable away from its seat under the action of fluid pressure to allow fluid to flow through the valve assembly to the nozzle assembly and adapted to be held In its open position by fluid pressure on its lower surface.

Preferably, the lower surface of the valve member is flat. By providing a flat lower surface extending perpendicularly to the flow direction the valve assembly can be made slimmer for a given fluid pressure so improving its ability to be housed on a vehicle body.

In the telescopic washer disclosed in FR-A-2523909, the arrangement is such that the fluid flow undergoes a perpendicular change of direction through the valve assembly. Thus, the nozzle must extend perpendicularly to the nozzle carrier, so that the width of the telescopic washer is increased.

According to a preferred embodiment of the present invention, the relative movement between the piston and cylinder is along an axis with the elongate nozzle carrier extending parallel to said axis, and the direction of fluid flow through the valve assembly being parallel to said axis. Thus, the washing device is slimmer and more streamlined than the known device in the normal operating axis of the device.

Preferably, the valve member includes a stem depending from the lower surface and located within said end region of the nozzle carrier. The location of the stem in the end region of the carrier helps to prevent the valve member from tipping about an axis! perpendicular to the stem and therefore prevents the valve from jamming and maintains the lower surface perpendicularly to the fluid flow.

The portion of the -stem adjacent the flat lower surface may be tapered, said tapered portion being adapted to seal against the seat of the valve assembly. The tapered portion assists in providing a waterproof seal when the valve is in its closed position, and provides a rigid surface for supporting the valve spring.

The valve assembly may further comprise a housing having an inner surface against which the valve member sealingly and slidably abuts, and the valve member includes a plurality of apertures arranged to allow fluid flow through the valve member when the valve member is in its open position. Thus, the valve member is supported within the housing when the valve is open, while the apertures assist the smooth flow of fluid through the valve, parallel to the axis of the elongate nozzle carrier. The provision of these apertures enables the width of the assembly to be further reduced.

In addition, when the valve member includes the tapered portion, fluid flow is directed through the apertures by means of the tapered portion.

Preferably, said movable one of the piston and cylinder is movable under the action of fluid pressure, and said r biassing means and said valve biassing means each comprise a spring, the stiffnesses of the spring and the valve spring being selected so that the fluid pressure required to move said movable one of the piston and cylinder is less than that required to move the valve member away from its seat, and so that the fluid pressure at which the valve member is returned to its seat by the action of the valve spring is greater than the fluid pressure at which said movable one of the piston and cylinder is returned to its normal position by the action of the spring. This ensures that fluid can only escape from the nozzle when the nozzle is in its operative position.

Specific embodiments of the present invention will now be described with reference to the accompanying drawings, in which: - FIGURE 1 shows the location of a f luid delivery system in a vehicle.

FIGURE 2 shows a cross-sectional view of a telescopic washer according to one embodiment of the present invention; FIGURE 3 shows a cross-sectional view of the washer of Figure 1, in operation; 1 FIGURE 4 shows a perspective view of the valve member of the washer of Figures 2 and 3.

Figure 1 illustrates diagrammatically the front of a car with a headlamp 14 and a bumper 16. A supply reservoir 18 housed within the car body contains a cleaning fluid which can be delivered to a telescopic washer 20 by way of a fluid delivery conduit 21. The telescopic washer 20 comprises an outer cylinder 22 which as will be described in more detail hereinafter houses a piston which carries a nozzle support portion to which is secured a nozzle 24 for delivering cleaning fluid to the headlamp screen. The thick black lines show the telescopic washer in its inoperative position while the dotted lines show the fluid delivery nozzle in its fluid delivery location.

Figures 2 and 3 show a telescopic washer according to the present invention, having an inlet 31.to a housing 30.

The housing 30 is cylindrical, with a tapered upper end region 30a. The inlet 31 is provided at its lower end 41. A nozzle carrier 32 is formed with an annular portion 35 adjacent at its proximal end region 40, the annular portion 35 acting as a piston 35 slidably mounted within the housing 30. The nozzle carrier 32 and the annular portion 35 are thus movable together within the housing 30. A sealing member 36 abuts the annular portion 35 to provide a water-tight seal between the annular portion 35 and the inner wall of the housing 30. Thus, the interior of the housing 30 is divided into a lower fluid space 37 and an upper air apace 38.

A distal end 138 of the nozzle carrier 32 extends through an aperture 39 in the housing 30, while, in the inoperative position shown in Figure 1, the sealing member 36 rests against a stop portion 42 at a lower end 41 of the housing 30.

A compression spring 43 is provided in the air space 38 of the housing 30 coaxially around the nozzle carrier 32. One end of the spring 43 abuts the annular portion 35 and the other end of the spring 43 abuts a top surf ace 44 of the housing 30. The compression spring 43 acts on the annular portion 35 so as to bias the nozzle carrier 32 into its inoperative position within the housing 30. The compression spring 43 is assembled under compression within the housing 30 so that the nozzle carrier 32 is normally held in the inoperative position.

On the distal end 38 of the nozzle carrier 32 there is mounted a nozzle assembly 34, comprising a nozzle housing 57 which carries a nozzle 45 and which has a recess 49 for accommodating a valve assembly 33.

The valve assembly 33, shown in detail in Figure 3, has a poppet-type valve which comprises a cylindrical stem 52, which fits within the distal end 38 of the nozzle carrier 32, a tapered conical portion 46, adapted to seal against a seat 54 provided in the inner wall of the distal end 38 of the nozzle carrier 32 and a rim 47 provided at the wider end of the tapered portion 46, which abuts the inner wall of the recess 49 within the nozzle housing 51, so that the valve is slidably mounted within the recess 49. The rim 47 is provided with through holes 48 which allow f luid to f low through the valve, and has a f lat lower surface 55 against which fluid pressure is exerted.

The valve assembly includes a valve spring 50 mounted within the recess 49 so that one end thereof abuts the upper surf ace of the rim 47 and is held in position by a spring retaining portion 53 of the valve, and the other end thereof abuts an end wall of the recess 49 so as to bias the valve towards the distal end 38 of the nozzle carrier, thereby normally providing a water-tight seal.

When washing fluid is introduced through the inlet 31, the f luid pressure acts on the seal 36 and also enters the nozzle carrier to act on the valve of the valve assembly 33. The fluid pressure overcomes the return force of the compression spring 43 and drives the nozzle carrier 32 into its operative position. However, the stiffness of the valve spring 50 is chosen so -that the f luid pressure of the f luid within the nozzle carrier is insuf f icient to force the valve into an open position until the washer is in its fully operative position.

It will be appreciated that the stiffnesses of the compression spring 43 and the valve spring 50 must be chosen so as to ensure the sequence of operation described above. The dimensions of the valve element 33 may then be chosen to ensure optimum performance of the washer.

The rim 47 of the valve element 33 presents a flat surface to the flow of fluid, which enhances the force on the valve element 33 due to fluid pressure. Thus, for a given fluid pressure, the width of the valve element 33 is less than corresponding valve elements in the prior art. Moreover, the direction of fluid flow is not diverted in the valve 33. Thus the telescopic washer may be made comparatively slim, for ease of mounting on a vehicle.

Claims

1. A washing device for supplying washing f luid to vehicle screens and comprising a piston mounted within a cylinder, one of the piston and cylinder being movable relative to the other against the action of biassing means, and an elongate nozzle carrier connected for movement with the movable one of the piston and cylinder and adapted to carry at one of its end regions a nozzle assembly for the delivery of washing fluid, the device including a valve assembly at said end region of the nozzle carrier, the valve assembly comprising a valve member having a lower surface extending perpendicularly to the direction of flow of washing fluid and valve biassing means for holding the valve member against a valve seat, the valve member being movable away from its seat under the action of fluid pressure to allow fluid to flow through the valve assembly to the nozzle assembly and adapted to be held in its open position by fluid pressure on its lower surface.

2. A device as claimed in claim 1, in which the lower surface of the valve member is flat.

3. A device as claimed in claim 1 or 2, in which the relative movement between the piston and cylinder is along an axis with the elongate nozzle carrier extending parallel to said axis, the direction of fluid flow through the valve assembly being parallel to said axis.

4. A device as claimed in any one of claims 1 to 3, in which the valve member includes a stem depending from the lower surface and located within said end region of the nozzle carrier.

5. A device as claimed in claim 4, in which a portion of the stem adjacent the flat lower surface is tapered, said tapered portion being adapted to seal against the seat of the valve assembly.

6. A device as claimed in any _preceding claim, in which the valve assembly further comprises a housing having an inner surface against which the valve member sealingly and slidably abuts, and the valve member includes a plurality of apertures arranged to allow fluid flow through the valve member when the valve member is in its open position.

7. A device as claimed in any preceding claim, in which said movable one of the piston and cylinder is movable under the action of fluid pressure, and said biassing means and said valve biassing means each comprise a spring, the stiffnesses of the spring and the valve spring being selected so that the fluid pressure required to move said movable one of the piston and cylinder is less than that required to move the valve member away from its seat, and so that the fluid pressure at which the valve member is returned to its seat by the action of the valve spring is greater than the fluid pressure at which said movable one of the piston and cylinder is returned to its normal position by the action of the spring.

8. A device substantially as herein described with reference to and as shown in the accompanying Figures 1,2, and 3.