GB2195235A

GB2195235A - Wiper arm assembly

Info

Publication number: GB2195235A
Application number: GB08622233A
Authority: GB
Inventors: Christian Beneteau
Original assignee: Champion Spark Plug Europe SA
Current assignee: Champion Spark Plug Europe SA
Priority date: 1986-09-16
Filing date: 1986-09-16
Publication date: 1988-04-07
Anticipated expiration: 2006-09-16
Also published as: GB2195235B; GB8622233D0

Abstract

A wiper arm assembly comprises wiper arm 1, 2 pivotally attached to mounting head 3 by pivot pin 9, rod 4 pivotally attached by pivot pin 11 to mounting head at one end and connectable to drive shaft 6 at the other end, and a rod 5 connectable by joints 12, 13 to the mounting head and to a plate 15 having a pivot pin located offset from the axis of the drive shaft. Assembly and disassembly of a wiper blade on and from the outer end of the wiper arm, as compared with conventional pantograph wiper systems, are said to be facilitated; and visibility is apparently improved by the reduction of elements which oscillate in front of a driver's eyes. <IMAGE>

Description

SPECIFICATION Wiper arm assembly The present invention relates to a wiper arm assembly, for example for motor vehicles, comprising a wiper arm which is pivotally attached to a mounting head by means of a pivot pin extending substantially parallel to the surface to be wiped. In particular the invention relates to a wiper arm assembly of which the wiping pattern is the same or similar to the wiping pattern obtained by a wiper system of the pantograph type.

A pantograph wiper system is shown in the British patent 1,234,040. It comprises a main and a secondary arm 2, 12 which both extend from the drive shaft 4 to the medium portion of the wiper blade 24, 26. Under the action of the secondary arm 12 - which is pivotally connected to the excenter 20 provided on the bush 6 of the drive shaft 4 at one of its ends and pivotally connected to the pivot block 8 provided at the medium portion of the wiper blade 24, 26 at the other of its ends - the wiper blade 24, 26 can swivel about the vertical pin 10 provided at the outer end of the main arm 2. This feature allows the wiping pattern to be increased with respect to the wiping pattern of a conventional wiper arm, i.e. with respect to a non pantograph wiper system.

An object of the invention is to provide a wiper arm assembly of which the wiping pattern is the same or similar to the wiping pattern of the above described pantograph system, but wherein a conventional wiper arm can be used, i.e. a wiper arm which is not provided with a vertical pin at its out end.

The invention also enables a wiper arm assembly to be provided wherein the wiper blade can be more easily mounted onto and dismounted from the outer end of the wiper arm than in a pantograph system. The easier mounting/dismounting of the wiper blade is due to the fact that in an assembly according to the invention the wiper arm is not provided with a vertical pin at its outer end. This indeed simplifies the connection between the wiper blade and the wiper arm.

The invention also enables a wiper arm assembly to be provided wherein the volume (or apparent surface) of the elements which oscillate in front of the driver's eyes are reduced to a minimum as compared to a pantograph wiper system.

In accordance with the present invention there is provided a wiper arm assembly, for example for motor vehicles, comprising a wiper arm which is pivotally attached to a mounting head by means- of a pivot pin extending substantially parallel to the surface to be wiped, wherein said mounting head is linked to the drive shaft of the assembly by a first rod which is pivotally attached to the mounting head by means of a pivot pin extending substantially perpendicularly to the surface to be wiped, said first rod being rigidly secured to the drive shaft, and by means of a second rod which, at one of its ends, is attached to the mounting head by means of a first joint and which, at the other of its ends, is attached to an excentric, located near the drive shaft, by means of a second joint.

In order that the invention may be better understood, an embodiment thereof, which is given by way of example only, will now be described with reference to the appended drawings, wherein: Figure 1 is an elevational view of the wiper arm assembly; Figure 2 is a top view of the wiper arm assembly of Fig. 1; Figure 3 is a section along line Ill-Ill of Fig.

2; Figure 4 is a section along line IV-IV of Fig.

2; Figure 5 is a partial section along line V-V of Fig. 2; and Figure 6 is a partial section along line VI-VI of Fig. 2.

As can be seen on Fig. 1 and Fig. 2 the wiper arm assembly comprises: a conventional wiper arm 1, 2, a mounting head 3, and two rods 4, 5 which link the mounting head 3 respectively to the drive shaft 6 and the excenter 15.

Fig. 3 shows the detail of the conventional wiper arm, i.e. the extension rod 2 which is attached to the housing 1 by means of the rivet 2a and to the free end of which the wiper blade (not shown) is connected to and the compression spring 7 with its supporting rod 8.

The wiper arm 1, 2 can rotate with respect to the mounting head 3 about the pivot pin 9 and the compression spring 7 and its supporting rod 8 can rotate with respect to the same mounting head 3 about the pivot pin 10. The pivot pin 9 and the pivot pin 10 both extend substantially parallel to the surface to be wiped. When the wiper arm assembly is working the spring 7 which acts on the bent portion 2b of the extension rod 2 pushes the free end of said extension rod 2, and consequently the wiper blade (not shown), towards the surface to be wiped.

As already said above the rods 4, 5 (first rod 4 and second rod 5) link the mounting head 3 respectively to the drive shaft 6 and the excenter 15. The outer end portion of the first rod 4 has the form of a fork between the two branches 4a, 4b of which extends the recess 4c. Whilst the outer end 3a of the mounting head 3 supports the two pivot pins 9, 10, the inner end of the mounting head 3 projects into said recess 4c of the first rod 4 and is retained therein by the pivot pin 11 which extends substantially perpendicularly to the surface to be wiped and about the geo metrical axis of which the mounting head 3 and consequently the conventional wiper arm 1, 2 and the wiper blade (not shown) can rotate.

As can be best seen on Fig. 2 the mounting head 3 has a sidewardly projecting portion 3b to which the second rod 5 is connected by means of the joint 12. The details of the connection between the portion 3b of the mounting head 3 and the second rod 5 are shown in Fig. 4. The joint 12 is made of a flexible material which has an elongate form and which, in its central portion 12a, has a circular cross section which is smaller than the cross section of the two end portions of said joint 12. The flexible material used is an elastomer, such as for example a polyester elastomer.

The connection between the joint 12 and the portion 3b of the mounting head 3 as well as the connection between the joint 12 and the second rod 5 can be of any type known in prior art. One or both of said connections can, for example, be a snap-on connection. In Fig. 4 the connection between the portion 3b of the mounting head 3 and the joint 12 is a snap-on connection.

When the wiper arm assembly is working the reduced circular cross section 12a of the joint 12 can absorb relative movements (in any direction) between the mounting head 3 and the second rod 5. At the same time the second rod 5 limits and controls the rotating movement of the mounting head 3 about the pivot pin 11 which extends substantially perpendicularly to the surface to be wiped.

At its inner end, i.e. at its end near the drive shaft 6, the first rod 4 is rigidly attached to said shaft 6. As schematically shown in Fig. 1 and Fig. 5 the drive shaft 6 is inserted into the opening 4d provided in the rod 4 and is locked therein by means of a nut (not shown) tightened on the threaded portion 6a of the shaft 6.

The inner end of the second rod 5 is connected to the excenter 15 by means of the joint 13, 14 (Fig. 1, 5 and 6). This second joint 13, 14 comprises an element 13 provided with two legs 13a, 13b which are substantially perpendicular one with respect to the other. One of said legs (13a) is rigidly secured to the second rod 5 and the other of said legs (13b) is connected to the pivot pin 14 provided on the excenter 15 in such a way that it can swivel about its longitudinal axis on said pivot pin 14. Thus the second rod 5 can swivel about the pivot pin 14.

In the embodiment shown in Fig. 5 and Fig.

6 the leg 13a of the element 13 is snapped onto the inner end of the second rod 5 and the leg 13b of said same element 13 is snapped onto the pivot pin 14. Other embodiments are possible and the element 13 is preferably made of an appropriate plastic material.

When the thus described new wiper arm assembly works the drive shaft 6 imparts an oscillating movement to the first rod 4 and consequently to the mounting head 3, to the conventional wiper arm 1, 2 and to the wiper blade (not shown). At the same time the second rod controls the rotation of the mounting head 3 about the pivot pin 11. The second rod 5 thus controls an oscillating movement of the mounting head/wiper arm/wiper blade about the pivot pin 11. The resulting movement of the wiper blade is a complex movement giving an increased wiping pattern.

Claims

1. A wiper arm assembly, for example for motor vehicles, comprising a wiper arm which is pivotally attached to a mounting head by means of a pivot pin extending substantially parallel to the surface to be wiped, wherein said mounting head is linked to the drive shaft of the assembly by a first rod which is pivotally attached to the mounting head by means of a pivot pin extending substantially perpendicularly to the surface to be wiped, said first rod being rigidly secured to the drive shaft and by means of a second rod which, at one of its ends, is attached to the mounting head by means of a first joint and which, at the other of its ends, is attached to an excenter located near the drive shaft by means of a second joint.

2. A wiper arm assembly according to claim 1, wherein said first joint is made of a flexible material which has an elongate form and which, in its central portion has a substantially circular cross section.

3. A wiper arm assembly according to claim 2, wherein the central portion of the elongate first joint has a cross section which is substantially smaller than the cross section of the two end portions of said joint.

4. A wiper arm assembly according to claim 1, 2 or 3, wherein the first joint is made of an elastomer, such as for example a polyester elastomer.

5. A wiper arm assembly according to any one of claims 1 to 4, wherein said second joint comprises an element provided with two legs which are substantially perpendicular one with respect to the other, that one of the legs is rigidly secured to said second rod and that the other leg is capable of swivelling about its longitudinal axis on a pivot pin provided on said excenter.

6. A wiper arm assembly according to claim 5, wherein the element provided with two legs is made of an appropriate plastic material.

7. A wiper arm assembly substantially as herein described with reference to the accompanying drawings.