AU601032B2

AU601032B2 - Pivot joint

Info

Publication number: AU601032B2
Application number: AU13887/88A
Authority: AU
Inventors: Peter John Biggs
Original assignee: Trico Ltd
Current assignee: Trico Ltd
Priority date: 1987-03-30
Filing date: 1988-03-30
Publication date: 1990-08-30
Anticipated expiration: 2008-03-30
Also published as: AU1388788A; BE1000824A3; GB8807412D0; JPS641649A; GB2202899B; GB8707566D0; JP2671955B2; GB2202899A; DE3810893A1

Description

COMMONWEALTH OF AUSTRALIA6 0 3 2 1 PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Class I nt. Class Application Number- Lodged: Complete Specification Lodged: Accepted: 0 a Published: Priority: Related Art: 9 a Name of Applicant: TRICO-FOLBERTH LIMITED a AarssfAplcat Great West Road, Brentford Road, Middlesex TW8 9HP, England 00 Actual Inventor: Address for Service: PETER JOHN BIGGS EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

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

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PIVOT TOINT Th is invention relates t o a pivot joint which i s 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.

Problems exist in the manufacture of windscreen wipers due to the necessity, very often, of pivoting metal boo parts together. These joints tend to be noisy and have a o 00 0o0" tendency to suffer from wear and corrosion. Various 0 0 0015 proposals have been made for overcoming these problems, 6 be ,00 94for example, by the, provision of plastics members between the metal parts of the joints, but these have not proved entirely satisfactory from a manufacturing standpoint although they have worked satisfactorily in 9 20 use.

The present invention seeks to provide a new and 0 b improved pivot joint which is relativly inexpensive to manufacture and use and which overcomes or reduces some or all of the above problems.

According to the invention, there is provided a pivot joint for' pivotting together first and second mem bers, at least the first of which is of channel section at the joint and the second of which is adapted to seat within the first, the pivot joint comprising a plastics joint body of generally channel section adapted to sit within the first member and to receive the second member therewithin, the joint body or first member having a first pair of trunnion members adapted to cooperate with apertures in the first member or joint body respectively j 2 and the joint body having a second pair of tru members extending inwardly and cooperating with a of aligned keyhole slots provided in the outer su of the second member.

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nnion pair rface C 4r 4r 44 4 44 4 4 4 4 4.

Further according to the invention, there is provided a pivot joint for pivotting together first and second members, at least the first of which is of channel section at the joint and the second of which is adapted to seat within the first, the pivot joint comprising a plastics joint body of generally channel section adapted to sit within the first member and to receive the second member therewithin, the joint body having a first pair of aligned trunnion members adapted to cooperate with aligned apertures in the first member respectively and a second pair of trunnion members extending inwardly and cooperating with a pair of aligned keyhole slots provided in the outer side surfaces of the second member.

All the trunnion members may be coaxial.

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Preferably, the second member is also of channel section in the region of the pivot joint and the keyhole slots therein comprise apertures extending through the material of the second member.

The invention will now be described in greater detail, by way of example, with reference to the drawings, in which Figure 1 is a perspective view of a completed pivot joint in accordance with the invention; Figure 2 is a perspective view of the joint body used in the construction of the pivot joint shown in figure 1; i r 3 4 Figure 3 is an exploded view of the parts of the joint shown in figure 1, and Figure 4 is a sectional view of the joint taken on the line IV-.V of figure 1.

Referring firstly to figure i of the drawings, there is shown a pivot joint i between two members 2 and 3, the first of which is the primary yoke 2 of the harness of a windscreen wiper blade and the second of which (3) is a secondary yoke of the harness. The two members 2 and 3 are pivotably connected togther by means of a joint body 4 of plastics material which can be seen in greater detail in figure 2 As can be seen from figure 2, the joint body 4 comprises a generally channel sectioned member having a first pair of trunnion members 6 extending outwardly from the side walls 7 of the channel and adapted to cooperate with two aligned apertures 8 in the primary yoke 2. A second pair of trunnion members 9 is provided extending inwardly from the side walls 7 of the channel and adapted to cooperate with keyhole slots 12 provided in the second member or secondary yoke 3. These keyhole slots can be seen from figure 3. The joint body 4 is provided at one end with an enlarged portion 14 connected to the remainder of the joint body by a shoulder which, when the joint is assembled, fits against the end of the primary yoke 2 and will act both to protect the open end of the joint and alleviate the effect of end thrust on the joint. In addition, it also acts as an alignment aid when assembling the joint. it will also be seen that the base and part of the sides of the joint body 4 are cut away at 18 in the central region to increase the resiliency of the side walls.

4 The assembly of the above described pivot joint will now be considered:- Referring in particular to figures 3 and 4, the plastics joint body 4 is pushed upwardly into the channel section of the primary yoke 2, using the enlarged end portion 14 of the joint body 4 as a guide. The channel sides 7 of the joint body are pushed together to permit the exterior pair of trunnions to pass between the channel sides of the primary yoke 2. This operation can be successfully carried out if a suitable plastics material is chosen for the joint body 4. Once the joint body 4 has been pushed home into the primary yoke 2, the exterior pair of trunnion members 6 will be aligned with the apertures 8 in the primary yoke 2 and, by virtue of the resilience of the joint body, these members 6 will snap into the apertures 8, thus securing the joint body 4 within the primary yoke 2. It will be seen that, due to the shape of the joint body 4, the joint body 4 will be rigidly attached to the primary yoke 2 and no pivotting will take place between the joint body 4 and the primary yoke 2.

Next the secondary yoke 3 is offered up into the joint body 4 so that the inner pair of trunnion members 9 rest in the mouth 16 of the keyhole slots 12 in the secondary yoke 3. Ohce in position, force is applied between the primary and secondary yokes 2 and 3 so as to push the inner pair of trunnions 9, with a click action, into the recesses 17 of the keyhole slots 12, thus securing the secondary yoke 3 to the joint body 4, and thus to the primary yoke 2, in pivotal fashion. In the particular construction shown, it will be seen that the pivotting takes place entirely between the secondary yoke 3 and the joint body 4.

L Although in the case of a pivot joint for a windscreen wiper blade as shown there is no need for detachment of the joint, nevertheless, it is possible to detach the joint by applying the assembly steps in reverse should this be desireo.

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 cut away portions of the base and sides of the joint body can be omitted if desired provided that the plastics material used retains sufficient resiliency to allow the joint body to be inserted into the primary yoke. instead of the exterior trunnions being provided on the joint body, the primary yoke could be providd with inwardly directed projections, for example, produced by indenting the side walls of th channel of the primary yoke 2, the projections cooperating wit~h recesses provided within the joint body. The enlarged end part 14 of the joint body may be omitted if desired since, while it is useful in the pivot joint described, it is not essential to the functioning of the joint.

It will be appreciated that while the invention has been described in relation to the joint between primary ano secondary yokes of a windscreen wiper harness, the invention' is equally applicable to joints between secondary and further subsidiary yokes or levers of the harness. It should equally be noted that the invention is not limited to pivot joints in windscreen wipers but can be used in any circumstance where such a pivot joint might be useful.

From the above described embodimeits it will be seen that a pivot joint has been described which is of d 6 relatively simple construction, which is enexpensive to manufacture and use and which provides an effective Scounter to the above stated problems with existing metal 1 to metal joints.

Claims

1. A pivot joint for pivotting together first and second members, at least the first of which is of channel to seat within the first, the pivot joint comprisingseto ttejitadth eodo hc sa ae plastics joint body of generally channel section adapted to sit within the first member and to receive the second member therewithin, the joint body or first member i cooperate with apertures in the first member or joint body respectively and the joint body having a second pair of -runnion members extending inwardly and cooperating with a pair of aligned keyhole slots provided in the outer surface of the second member. oil2. A pivot joint for pivotting together first and second members, at least the first of which is of channel section at the joint and the second of which is adapted to seat within the first, the pivot joint comprising a plastics joint body of generally channel section adapted to sit within the first member and to receive the second member therewithin, the joint body having a first pair I of aligned trunnion members adapted to cooperate with f aligned apertures in the first member and a second pair of trunnion members extending inwardly and cooperating with a pair of aligned keyhole slots provided in the I outer side surfaces of the second member.

33.A pivot join as claimed in claim 2, wherein all the trunnion members are coaxia. 8 4. A pivot joint as claimed in claim 2 or 3, wherein the second member is also of channel section in the region of the pivot joint and the keyhole slots therein comprise apertures extending through the material of the second member, A pivot joint as claimed in claim 4, wherein the stems of the keyholes of the keyhole slots extend into the base of the channel of the second member. 6. A pivot joint as claimed in any one of claims 2 to wherein the base of the channel of the joint body is cut away between the ends of the joint body so as to increase the resilience of the side walls thereof. 7. A pivot joint as claimed in any one of claims 2 to 6, wherein the joint body is substantially fixed relative to the first member and is pivotable relative to the second member. 8. A pivot joint as claimed in any one of claims i to 7, wherein the two members are yokes or levers of the harness of a windscreen wiper blade. 9. A pivot joint substantially as described herein with reference to the drawings. DATED this 30th day of March 1988. TRICO-FOLBERTH LIMITED EDWD. WATERS SONS PATENT ATTORNEYS QUEEN STREET MELBOURNE. VIC. 3000.