AU711890B2

AU711890B2 - Improvements in drive arm assemblies for wiper blades

Info

Publication number: AU711890B2
Application number: AU70388/96A
Authority: AU
Inventors: Peter Munroe Smith
Original assignee: Trico Products Corp
Current assignee: Trico Products Corp
Priority date: 1995-10-26
Filing date: 1996-10-24
Publication date: 1999-10-21
Anticipated expiration: 2016-10-24
Also published as: AU7038896A

Description

F/uu/llU 28/591 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT a Application Number: Lodged: Invention Title: IMPROVEMENTS IN DRIVE ARM ASSEMBLIES FOR WIPER BLADES The following statement is a full description of this invention, including the best method of performing it known to us 1 IMPROVEMENTS IN DRIVE ARM ASSEMBLIES FOR WIPER BLADES The present invention relates to improvements in drive arm assemblies for wiper blades.

Conventionally, wiper blade drive arm assemblies comprise a drive head adapted to be secured to a drive system including a drive motor for oscillating motion. The drive arm assembly normally includes a drive arm member pivoted to the drive head with the support harness for the wiper blade pivoted to an outer end of the drive arm member. A spring arrangement is located between the drive head and the drive arm member so as to provide a downward force on the wiper support harness so as to urge the wiper blade towards the windscreen when in use. The spring arrangement is also configured to enable the drive arm member to be pivoted away from the windscreen to be held in a locked back position by the spring arrangement being in an over centre position whereby the 15 windscreen can be cleaned or perhaps the wiper blades can be changed.

Commonly the pivot connection of the drive arm member to the drive head is created by providing a pair of flanges extending from side walls of the drive arm member rearwardly to be located outwardly of and adjacent side walls of the drive head with a pivot pin being located through the pair of flanges of the drive 20 arm member and the side walls of the drive head. A stop to prevent movement of the drive arm member beyond a predetermined locked back position is provided by a top wall edge of the drive arm member extending between the pair of pivot mounting flanges being arranged to engage a top wall of the drive head. While arrangements of this general type do work satisfactorily, they unfortunately also have a practical disadvantage in that when the drive arm member is moved toward the locked back position, it is possible to damage or crack the paint work on the drive head by the aforesaid engagement of the rear top edge on the top surface of the drive head. This can provide an unsightly appearance but also can promote premature corrosion and possible failure of the drive head.

The objective therefore of the present invention is to provide an improved drive arm assembly for a wiper blade which will substantially overcome the difficulties discussed above with existing or conventional drive arm assemblies.

Accordingly, the present invention provides a pivot connection between two pivotably linked members, being respectively a drive head and a drive arm of a wiper drive arm assembly, said pivot connection comprising laterally disposed side wall portions on one of said members arranged to be pivotally connected about the sides of the other of said members and stop means acting between said members in lateral side zones to limit relative pivoting movement between said members to an extent such that an end edge of a top wall of said drive arm, located and extending between said laterally disposed side wall portions, is disposed above but does not contact a central zone of a top wall of the drive head in a locked back position of the drive arm.

:Preferably, at least one or both of said laterally disposed drive arm side oo 15 wall portions are arranged to be received within recessed zones in drive head side wall regions with the pivot pin (or pins) extending through the laterally disposed side wall portions.

an alternative embodiment, it may be possible to arrange side wall portions of the drive arm within side wall portions of the drive head, with the 20 pivot pin (or pins) extending through the laterally disposed side wall portions.

Conveniently, the stop means comprises a first formation means on said drive head adapted to engage with a second formation means located on said drive arm with said first and second formation means engaging in the locked go 3 back position, said first and second formation means being arranged at or adjacent one or both lateral side zones of the pivot connection. Preferably, the first formation means comprises a portion of an edge of the or each recessed zone in the drive head side wall regions. Preferably the second formation means comprises a portion of an edge of the laterally disposed drive arm side wall portions.

By arrangements of the aforementioned type, the required functional performance of the wiper drive assembly is achieved but damage and visible unsightly appearance to the top surface of the drive head is prevented.

One preferred embodiment will hereinafter be described with reference to the accompanying drawings in which o*.Figures 1A and 1B are respectively a side section view and a top plan view of a wiper drive assembly according to the prior art; Figure 2 is a top plan view of a wiper drive assembly according to the 15 present invention; Figure 3 is a detailed plan view of the pivot area marked B in Figure 2; Figure 4 is a side elevation view of the wiper drive assembly shown in Figure 2; Figure 5 is a detailed side view of the pivot area marked A in Figure 4; So. 20 Figure 6 is a side elevation view similar to Figure 4 showing the wiper drive arm in a locked back position; and ~Figure 7 is a detailed view of the pivot area marked A in Figure 6.

S°Referring first to Figures 1A and 1B, a conventional wiper drive arm assembly 10 is illustrated comprising a drive head 11 adapted at 12 to be connected to a drive system (not shown). A drive arm 13 is shown having a pair of rearwardly extending flanges 14, 15 extending from side walls 16, 17 of the drive arm 13 such that the flanges are located outwardly of side walls 18, 19 of the drive head 11. A pivot pin 20 connects the flanges 14, 15 to the side walls 18, 19 of the drive head with a spring assembly 21 acting between the head 11 and the drive arm 13 to either provide a force urging the free end (not shown) of the arm 13 towards a windscreen (in use) or alternatively to provide a hold or locked back force when the arm 13 is pivoted counter clockwise (Figure 1A) about the pivot pin 20. The locked back position occurs when the rear edge 22 of the top surface 23 of the drive arm 13 engages the top surface 24 of the drive head 11 in the region identified by numeral 25. As discussed above, it is this contact that causes either an unsightly appearance or damage to the drive head.

Referring now to Figures 2 to 7, it should first be noted that the function and components of the assembly described are generally as discussed above with reference to Figures 1A and 1B except for the specific matters discussed hereinafter. In these embodiments, according to this preferred aspect of the present invention, the pivot connection 26 between the drive head 11 and the *drive arm 13 is created by forming recess zones 27 in the side walls 18, 19 of the drive head 11. By this arrangement, it is possible to arrange the width of the head 11 to be substantially the same as for the arm 13 thereby providing an improved appearance for the assembly 10 as a whole. The recessed zones 27 conveniently include a stop means 32 formed by a step portion 28 in an edge 29 of the zone. Conveniently, the stop step portion 28 is located adjacent to the top of the edge 29 so that it is located substantially at the corner between the side walls 18, 19 and the top wall 24 of the drive head. The stop step portion 28 is conveniently arranged to engage with a stop step portion 30 on the edge 31 of 20 the flanges 14, 15 of the drive arm 13 so that the step portions 28, 30 together form a limiting stop means 32 to prevent the arm 13 in Figure 5 pivoting about the pivot pin 20 in a clockwise direction beyond a limit or locked back position as shown in Figures 6 and 7. In the locked back position, the rear edge 22 of the top wall 23 of the drive arm 13 is maintained out of contact with the top wall 24 of the drive head 11. It is of course preferable that a limiting stop of the above described type be provided on both sides of the assembly but of course providing same on one side only would also be functional.

In this manner an improved appearance is achieved for a wiper drive assembly and moreover, unsightly damage to the drive head is prevented.

Claims

1. A pivot connection between two pivotably linked members, being respectively a drive head and a drive arm of a wiper drive arm assembly, said pivot connection comprising laterally disposed side wall portions on one of said members arranged to be pivotally connected about the sides of the other of said members and stop means acting between said members in lateral side zones to limit relative pivoting movement between said members to an extent such that an end edge of a top wall of said drive arm, located and extending between said laterally disposed side wall portions, is disposed above but does not contact a central zone of a top wall of the drive head in a locked back position of the drive arm.

2. A pivot connection according to Claim 1, wherein said stop means comprises a first formation means located on one of said members adapted to engage with a second formation means located on the other of said members in said locked back position of the drive arm, said first and second formation means being arranged at or adjacent one or both lateral side zones of the pivot connection.

3. A pivot connection according to Claim 1, wherein at least one of said laterally disposed side wall portions is arranged to be received in a recessed zone in a side wall region of the other of said members.

4. A pivot connection according to Claim 3, wherein both said laterally disposed side wall portions are arranged in a respective said recessed zone in the other of said members.

A pivot connection according to Claim 3 or Claim 4, wherein said stop means comprises a first formation means located on said drive head adapted to engage with a second formation means located on said drive arm in said locked back position of the drive arm, said first and second formation means being arranged at or adjacent one or both lateral side zones of the pivot connection.

6. A pivot connection according to Claim 5, wherein the first formation means comprises an edge of the or each said recessed zone in the drive head side wall regions.

7. A pivot connection according to Claim 5 or Claim 6, wherein the second formation means comprises a portion of an edge of at least one of the laterally disposed drive arm side wall portions.

8. A wiper blade assembly comprising a drive head, a drive arm, wiper blade arrangement connected to said drive arm and a pivot connection according to any one of Claims 1 to 7, arranged between said drive head and said drive arm. DATED THIS 25TH DAY OF AUGUST, 1999 TRICO PRODUCTS CORPORATION WATERMARK PATENT TRADEMARK ATTORNEYS *o 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA SKP:JC DOC 28 AU7038896.WPC