AU648289B2 - Pivot joint - Google Patents

Description

Form COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

8 289 Class Int. Class Application Number: Lodged: omplete Specification Lodged: t Accepted: 0 o Pjiority 0 Related Art: A r Published: 4 Name of Applicant i, i o A ddress of Applicant: a o e Actual Inventor Address for Service 0 I Address for Service TRICO PTY. LTD.

820 Princes Highway, Springvale. Victoria 3177, Australia PETER CARPENTER WATERMARK PATENT TRADEMARK ATTORNEYS.

LOCKED BAG NO. 5, HAWTHORN, VICTORIA 3122, AUSTRALIA Complete Specification for the invention entitled: PIVOT JOINT The following statement is a full description of this invention, including the best method of performing it known to ~T__j 2 PIVOT JOINT This invention relates to a pivot joint which is particularly but not exclusively useful in the manufacture of windscreen wipers.

In the manufacture of windscreen wipers, a number of pivot joints are used, particularly between the various yokes and/or levers of the windscreen wiper blade.

In the manufacture of windscreen wiper blades it is frequently necessary to pivot metal parts together. This can lead to manufacturing difficulties as well as joints which are noisy and are subject to wear and corrosion. One proposal for overcoming these difficulties has been the Ott provision of a plastic member between the metal parts of the joints. Although these members have proved to be satisfactory in use, difficulties remain in their o incorporation in the manufacturing process.

One such plastic member is described by the applicant in Australian patent number 586735. The described S member seats between the first and second yokes of a blade harness of a windscreen wiper and in order to prevent vertical slippage of the member with respect to the first external yoke, the first external yoke seats on and around more than three sides of the plastic member. The plastic member is fixed in a longitudinal direction by cooperating means on the member and on the external yoke.

The difficulty with the above configuration is that the requirement that the external yoke seat around more than 3 sides of the plastic member leads to a need for excess steps in the manufacturing process to form the external 30 yoke, for accuracy in construction of the joint because of the horizontal and vertical limitations on the insertion of the member into the external yoke and of course, a need for extra materials.

Hence, it is an object of the present invention to provide a new and improved pivot joint which is relatively inexpensive to manufacture and use aiid which overcomes or alleviates some or all of the above problems.

3 To this end there is provided a pivot joint comprising a joint body of substantial channel section having a base wall and spaced parallel side walls extending from edges of said base wall, the side walls of said joint body having pivot means for pivotal connection with a first member to be pivoted, said first member being intended to seat within the channel of said joint body, and a second member to be pivoted being intended to seat on and around said joint body, said joint body having means in the base wall for engagement with cooperating means in said second member such that said joint body is fixed in at least one longitudinal direction with respect to said second member, and external means 0 on said spaced parallel side walls for engagement with cooperating means on said second member such that said joint body is fixed in a direction parallel to o said side walls with re-oect to said second member.

This invention predicated on the surprising discovery that by providing external means on the spaced parallel side walls of the joint body and means in the base wall of the joint body for engagement with the second member to be pivoted to hold the joint body in fixed vertical and longitudinal relationship to the second member, economy of materials can be achieved, the manufacturing S 20 process of such pivot joints is improved and simplified and the use of such joints is also simplified.

a a In a preferred embodiment of this invention there is provided a pivot joint as defined hereinabove wherein said external means on said spaced parallel side walls of said joint body and said pivot means in said spaced parallel side walls of said joint body are located adjacent a front end of said joint body. Said means in a base wall of said joint body for engagement with cooperating means on a second member to be pivoted is a spring element directed outwardly from the base wall of the joint body preferably a detent located on a resilient tongue which extends from a rear end of said joint body towards said front end, and said cooperating means on said second member is an aperture in a base of said second member.

Preferably said external means comprise an outwardly and longitudinally extending rib on each side wall each of said ribs being parallel to one another The pivot means on the joint body may preferably comprise a pair of internal resilient trunnions which cooperate with recesses or apertures on said second member or vice versa. Alternatively the pivot means on the joint body may compnrise a pair of apertures in the joint body through which a pivot pin passes, the pivot pin passing also through one or more apertures in said second member.

In a more preferred form of the invrntion, the first and second members comprise yokes of the blade harness of a windscreen wiper which are to be o, pivoted together.

In a further aspect of the invention there is provided a joint body for use •intermediate two members, said joint body being of substantially channel crosssection having a base wall and spaced parallel side walls extending from edges of said base wall, the side walls of said joint body having pivot means for pivotal connection with a first of two members to be pivoted, means in the base wall for engagement with a second of two members to be pivoted, and external means on said spaced parallel side walls for engagement with a second of two members such that in use in engagement between said two members, said joint body is fixed in at least one longitudinal direction and in a direction parallel to said side walls with respect to the second of the two members.

AlT In a preferred form of this aspect of the invention said external means in the spaced parallel side walls of the joint body for engagement with a second of said members comprise an outwardly and longitudinally extending rib on each side wall of said joint body, each of said ribs being parallel to one another.

In a further preferred form of this aspect of the invention said pivot means are a pair of resilient internal trunnions and said means in the base wall of the joint body is a spring element directed outwardly from the base of the channel.

More preferably said spring element comprises a detent or projection carried by the end of a resilient tongue.

A most preferred form of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is an isometric view of a joint body according to the invention.

Figure 2 is a longitudinal section of a pivot joint according to the invention as applied to the joint between primary and secondary yokes of a windscreen wiper blade harness.

j- Figure 3 is a side view of a pivot joint according to the invention as applied to the joint between primary and secondary yokes of a windscreen wiper blade harness.

,Referring to Figures 2 and 3, the pivot joint 10 is shown formed between two members 11 and 12, suitably a primary and a secondary yoke respectively of a windscreen wiper blade harness. These yokes would normally be made of channel section metal, the secondary yoke usually being pivotally connected in its central region to one end of the primary yoke.

Referring to Figure 1, the pivot joint 10 comprises a joint body 13 of a 25 suitably resilient plastics material. It is generally of channel section and has a base web 14 and side flanges or walls 15. The base web 14 is formed with an opening 23 extending therethrough. A resilient tongue 18 of the same material as the base web 14 extends from one axial -6i 6 end 24 of the opening 23 towards the other axial end 25 of Ki the opening 23. The body of the tongue 18 lies essentially in the plane of the base web 14 but ends with a projection i 16 extending laterally outwaLly of the channel section of the joint body 13. The engagement of the projection 16 with a corresponding aperture 17 in the base of the primary yoke 11 prevents the joint body from being removed from the primary yoke 11 other than by lateral movement.

Each of the side walls 15 are provided with an inwardly facing trunnion 19 to engage a corresponding recess or aperture (not shown) in the secondary yoke 12 to act as a pivot. Both of the walls 15 are also provided with external elongate aligned lugs 20 which cooperate with aligned slots 21 in the opposite side walls 22 of the primary yoke 11.

15 It can be seen that the engagement of the external Z lugs 20 with the aligned slots 21 in the primary yoke 11 fixes the joint body laterally with respect to the primary t yoke 11 and prevents the joint body from leaving the yoke 11 other than by longitudinal movement in the direction of the primary yoke 11.

An abutment surface 24 is provided on the joint body 13 engageable with the end surface 26 of the primary yoke 11.

The assembly of the pivot joint shown in Figures 1 to 3 will now be described.

4 The secondary yoke 12 is first pushed up into the channel of the joint body 13 at a position in which when fully inserted, the trunnions 19 on the joint body 13 will t be aligned with the recesses or apertures (not shown) in the *444 S 44', 30 secondary yoke 12. To insert the secondary yoke 12, the S tt Ui si'de walls 15 are pushed together. This may happen automatically if the trunnions 19 are of suitable conical form.

Once the trunnions 19 have reached alignment with the recesses (not shown), the trunnions 19 will enter the recesses (not shown) allowing the side walls 7 to regain -7their original position. The joint body 13 is now pivotally secured to the secondary yoke 12.

In order to connect the joint body 13 together with the secondary yoke 12 to the primary yoke 11, the secondary yoke 11 is offered up to the primary yoke 11 and passes into the channel section of the primary yoke 11, care being taken to ensure that the part of the yoke 12 carrying the joint body 13 remains away from the primary yoke 11 but with the end of the joint body 13 having the trunnions 19 and the lugs 20 at the end of the primary yoke 11.

It will be appreciated that while the main part of the secondary yoke 12 can pass into the primary yoke 11 Ott* because of the projection 16 on the tongue 18 the joint body is LOO large to do this. With the appropriate part of the S 15 secondary yoke 12 inside the primary yoke 11 the two members o can be slid relative to each other so that the side walls and the base web 14 of the joint body 4 approach the free t I end of the primary yoke 11. If the projection 16 is now depressed and this can happen automatically if the end face of the projection 16 is suitably inclined it is possible to slide the joint body 13 together with the secondary yoke 12 into the primary yoke 11. As soon as the projection 16 registers with the aperture 17 in the base of the primary E yoke 11 it will snap thereinto. As this time, the abutment :25 surface 24 of the joint body 13 will be in substantial Sengagement with the end of the primary yoke 11 and the lugs will be engaged in the slots 21 in the primary yoke 11.

In this way the joint body 13 will be fixed longitudinally with respect to the primary yoke 11 and will be prevented ii .430 from leaving the primary yoke 11 downwardly since the lugs cannot disengage from the aligned slots 21 except in a longitudinal direction. However the secondary yoke 12 can still pivot with respect to the joint body 13 and thus with respect to the primay yoke 11 by a small angle.

While in the particular application to windscreen wipers, there is no necessity for the joint to be able to be dissassembled, nevertheless it is possible to dissassemble the above described joint as follows:- -8- The projection 16 is depressed to bring it clear of the aperture 17, whereupon it is possible to slide the two yokes 11 and 12 relative to each other so as to remove the joint body 13 from the primary yoke 11. Once this has been achieved the secondary yoke 12 can readily be extracted from the primary yoke 11. Then the side walls 15 can be pulled apart to enable the trunnions 19 to be removed from the recesses (not shown) and the joint body 13 can be pulled off the secondary yoke 12.

It will be appreciated that various modifications may be made to the above described embodiments without departing from the scope of the invention. For example, the roles of the trunnions 19 and recesses or apertures in the secondary yoke 12 may be reversed by providing trunnions on 15 the secondary yoke and apertures or recesses on the joint body.

Although the invention has been described with particular reference to windscreen wipers, the invention is equally applicable to other applications where this type of pivot joint or joint body may be useful.

6 a 04o£ Iq

Claims (11)

1. A pivot joint comprising a joint body of substantial channel section having a base wall and spaced parallel side walls extending from edges of said base wall, the side walls of said joint body having pivot means for pivotal connection with a first member to be pivoted, said first member being infended to seat within the channel of said joint body, and a second member to be pivoted being intended to seat on and around said joint body, said joint body having means in the base wall for engagement with cooperating means in said second member such that said joint body is fixed in at east one longitudinal direction with respect to said second member, and external means on said spaced parallel side walls for engagement with cooperating means on said second member such that said joint body is fixed in a direction parallel to said side walls with respect to said second member.

2. A pivot joint as claimed in claim 1 wherein said external means on said spaced parallel side walls are located adjacent a front end of said joint body.

S3. A pivot joint as claimed in claim 1 or 2 wherein said pivot means in the said walls of said joint body are located adjacent a front end thereof. i

4. A pivot joint as claimed in any one of claims 1 to 3 wherein said means in the base of the joint body for engagement with cooperating means in said second member is a detent mounted on an end of a resilient tongue, a.nd said cooperating means is an aperture in a base wall of said second member with which said detent engages.

A pivot joint as claimed in claim 4 wherein said tongue extends from a rear end of said joint body towards said front end. 1

6. A pivot joint as claimed in any one of claims 1 or 2 wherein said external means comprise an outwardly and longitudinally extending rib on each side t wall, each of said ribs being parallel to one another.

S7. A pivot joint as claimed in any one of claims 1 to 6 wherein said first and second members comprise yokes of the blade harness of a windscreen wiper which are to be pivoted together.

8. A pivot joint as claimed in any one of claims 1 to 7 wherein said first member comprises the primary yoke of a windscreen wiper blade harness and said second member comprises the secondary yoke of the windscreen wiper blade harness.

9. A joint body for use intermediate two members, said joint body being of substantially channel cross-section having a base wall and spaced parallel side walls extending from edges of said base wall, the side walls of said joint body having pivot means for pivotal connection with a first of two members to be pivoted, means in the base wall for engagement with a second of two members to be pivoted, and external means on said spaced parallel side walls for *I engagement with a second of two members such that in use in engagement between said two members, said joint body is fixed in at least one longitudina, direction and in a direction parallel to said side walls with respect to the second of the two members.

A joint body as claimed in claim 9 where,- said external means comprise an outwardly and longitudinally extending rib on each side wall of said joint body, each of said ribs being parallel to one another.

11. A joint body as claimed in claim 9 or 10 wherein said means in the base wall comprises a detent mounted on end of a resilient tongue extending fromnt wall comprises a detent mounted onamr end of a resilient tongue extending from rc-- 11 a rear end of said joint body towards said front end. DATED this 3rd day of November, 1993. TRICO PTY. LTD. WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA SKP:KJS:BB AU7121491.WPC DOC 39 IT 0T