GB2307398A

GB2307398A - Windscreen wiper system

Info

Publication number: GB2307398A
Application number: GB9523941A
Authority: GB
Inventors: Martin Ryan
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1995-11-23
Filing date: 1995-11-23
Publication date: 1997-05-28
Also published as: GB9523941D0

Abstract

In an intermittent windscreen wiper system the wiper blade 4 remains in the displaced position 8 for a pre-set time period so that the windscreen is regularly cleaned by a single wipe.

Description

WINDSCREEN WIPER SYSTEM The present invention relates to windscreen wiper system for a motor vehicle, and to a motor vehicle which is provided with the system.

A windscreen wiper is typically mounted on a vehicle bonnet, with the resilient wiper blade held against the bottom of the windscreen in a rest position. When the wiper control is switched on the wiper blade performs a wipe cycle in which it moves from the rest position across the windscreen to a displaced position and then back to the rest position. The wiper blade wipes water or other materials from the surface of the screen as it moves.

The wipe cycles continue one after another until the wiper control is switched off. Typically, if a wipe cycle is underway when the wiper control is switched off the wiper blade returns to the rest position before stopping.

It is well known to provide variable speed vehicle windscreen wipers so that the speed of the wipe cycle can be changed to suit different adverse weather conditions.

A faster wipe cycle would be selected, for example, for heavier rain.

It is also well known to provide an intermittent wipe in which the wiper pauses for a preset time between cycles.

Such an intermittent wipe is for use, for example, in conditions of light rain or intermittent rain.

Variable or intermittent speed wipers can be used more effectively than single speed wipers in different conditions, but all wipers distract from the view ahead when moving across the windscreen, and they temporarily reduce visibility when they push water across the field of view.

According to a first aspect of the present invention there is provided an intermittent windscreen wiper system comprising a wiper blade for mounting in relation to a vehicle windscreen so that the blade rests against the windscreen in a rest position, and means for moving the blade in a wipe cycle from the rest position to a displaced position, and back to the rest position, characterised in that during the wipe cycle the wiper blade remains in the displaced position for a preset waiting period before returning to the rest position.

By temporarily halting the wiper blade at the displaced position, the intermittent wiping operation is rendered more efficient, because a single wipe in each direction cleans the windscreen when required, rather than the pair of wipes used in a conventional intermittent wipe system.

In the conventional wipe arrangement the second (return) wipe is largely redundant because it comes too soon after the first (outward) wipe; indeed the second wipe can generate friction between the windscreen and the wiper blade which can cause an unpleasant noise.

For convenience hereinafter the wipe made by the blade moving from the rest position to the displaced position will be referred to as the outward wipe, and the wipe made by the blade moving from the displaced position to the rest position will be referred to as the return wipe.

It is preferred that during the intermittent wipe cycle the wiper blade waits for the same length of time in the displaced position as it does in the rest position, so that all wipes (outward or return) occur at regular intervals. It would however be possible for the blade to wait longer in either the rest position or the displaced position, but this would be less efficient under most weather conditions.

It is particularly preferred that the waiting period be adjustable, and/or that the wiper speed be adjustable, so that the driver can set these variables to suit changing weather or road conditions.

Conventional electronic control means may be used to regulate the wait period in the displaced position and/or the wait period in the rest position. Once the invention is properly understood, suitable electronic control means may readily be selected by persons skilled in the art of electronics.

For example the control means may comprise an electronic module integrated as part of the motor. The module may include some form of semiconductor switching device and a timer to control the switching of the semiconductor switch.

The control means may be sold separately for modifying a conventional windscreen wiper system. In accordance with a second aspect of the invention there is therefore provided control means for causing a vehicle windscreen wiper blade to move between a rest position and a displaced position, and back to the rest position, characterised in that during the wipe cycle the wiper blade remains in the displaced position for a preset waiting period before returning to the rest position.

In accordance with a third aspect of the present invention, there is also provided a motor vehicle which is provided with a windscreen wiper system as set forth above It is envisaged that the rest position will be the conventional one in which the wiper lies generally along the bottom of the windscreen, and the displaced position will be a position at the extreme of the sweep of the wiper blade, typically with the wiper blade axis in a generally vertical alignment on the windscreen. However it would of course be within the scope of the invention to reverse these positions so that the wiper lies along the bottom of the windscreen in the displaced position.

The windscreen wiper may be used alone, or as one of a pair, according to design preference.

Where a single wiper blade is used, it may sweep through an arc of about 1800 between the rest position and the displaced position as it wipes the driver and the passenger side of the windscreen.

The invention will now be further described, by way of example, with reference to the following drawing in which: Figure 1 is a schematic representation of a windscreen wiper in the rest position and in the displaced position.

The wiper blades 4 are each shown in the rest position on a vehicle windscreen 2. Each blade 4 is mounted on a wiper arm 3 which is movable about a pivot 6 by means of a motor (not shown) between the rest position and a displaced position 8. The blade 4 wipes the outside surface of the windscreen 2 as it sweeps between the rest position and the displaced position.

In intermittent wipe mode, the blade 4 waits for a pre-set time period, for example five seconds, before commencing a wipe cycle which comprises an outward wipe 10 and a return wipe 12.

After performing the outward wipe 10 to the displaced position 8, the blade 4 waits for a pre-set period of time, for example five seconds, before returning to the rest position in the return wipe 12.

Thus the windscreen gets wiped every five seconds (for example) by a single wipe, the wipes alternating between the outward wipe 10 and the return wipe 12.

When the driver switches off the wipers, the blades 4 return to the rest position before stopping.

The wiper blades 4 may of course by operated in a conventional manner instead of the intermittent manner described herein. For example they may carry out continuous speed wiping without any preset wait between the wipe cycles, or in the displaced position.

The invention therefore provides an improved intermittent windscreen wiper system, which cleans the screen with only a single wipe in any pre-set time period.

Claims

1. An intermittent windscreen wiper system comprising a wiper blade for mounting in relation to a vehicle windscreen so that the blade rests against the windscreen in a rest position, and means for moving the blade in a wipe cycle from the rest position to a displaced position, and back to the rest position, characterised in that during the wipe cycle the wiper blade remains in the displaced position for a preset waiting period before returning to the rest position.

2. A wiper system as claimed in Claim 1, wherein in operation the wiper blade waits for substantially the same time in the displaced position as it does in the rest position.

3. A wiper system as claimed in Claim 1 or Claim 2, wherein the waiting period is adjustable by the driver.

4. A wiper system as claimed in any one of the preceding claims, wherein the wiper speed is adjustable by the driver.

5. Control means for causing a vehicle windscreen wiper blade to move between a rest position and a displaced position, and back to the rest position, characterised in that during the wipe cycle the wiper blade remains in the displaced position for a preset waiting period before returning to the rest position.

6. A motor vehicle which is provided with a windscreen wiper system or control means therefor as claimed in any one of the preceding claims.