GB2203485A

GB2203485A - Pivot joint

Info

Publication number: GB2203485A
Application number: GB08805132A
Authority: GB
Inventors: Ivan Alfred Duck; Peter Cecil Pethers
Original assignee: Trico Ltd
Current assignee: Trico Ltd
Priority date: 1987-03-04
Filing date: 1988-03-03
Publication date: 1988-10-19
Anticipated expiration: 2008-03-03
Also published as: GB8705033D0; EP0281397A3; NZ223733A; EP0281397B1; BR8800925A; GB8805132D0; JP2661697B2; JPS63284055A; DE3873116D1; AU1263488A; ES2034191T3; KR880010957A; AU596278B2; DE3873116T2; EP0281397A2; GB2203485B; KR960008813B1

Description

A 2203485 PIVOT jOTNT Th Ls invention relates t 0 a pivot joint which i S

particularly but not exclusively useful in the manufacture of windscreen wipers.

in the manufacture of winds'creen wipers, a number of' pLvot 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 parts together. These joints tend to be noisy and have a tendency to suffer from wear and corrosion. Various proposals have been made for overcoming these problems, for example, by the provision of plastics members De.. tween the metal parts of the joints, but these have not proved entirely samisfactory Trom a manufacturing standpoint although they have jorked satisfactorily in use.

The present invention seeks TO provide a new and improved pivot joint which is relativiy 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 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 joint bodyof generally... channel section adapted to siy, within the first member and to receive the second mem. ber therewithin, the joint body having a pair of outwardly extending trunnions adapted to cooperate with apertures in the f irst member, aligned bores through sai d trunnions adapted to be aligned with aligned aperrures in the second member, and a pin adapted to extend through the apertures or the members and Through the bores of the trunnions of the joint body, the pin being retained in one of the bores of the joint body by means of one or more projections or recesses on the pin cooperating with a respective recesses or projections in the bore.

1C) Further according to the invention, there is provided a pivot joint comprising first and second members to be - member being of channel pivotted together, the f irst section at least at the joint and the second member being adapted to seat within the channell section of the t member; a joint body of generally channel section 15 first adapted to sit within the first member and to receive the second member within its channel section, The joint body having a pair of outwardly extending trunnions adapted to cooperate with apertures in the first member and aligned bores through said trunnions adapted to be aligned with aligned apertures in the second member; and a pivot pin adapted to extend through the apertures of' the members and through the bores of the trunnions of the joint body, the pin being retained in one of the bores of the joint body by means of one or more projections or grooves on the pin cooperating with respective grooves or projections in the bore.

Preferably, a single projection is provided in the form 30 of an annular rib and the cooperating recess is an annular groove.

The pin may be formed wizn the projection or projections and the bore may be provided with the groove or grooves.

Suitably, the members may be yokes of a windscreen wiper 9 1 t 4 first member may be the primary yoke blade harness. The.4 and the second member may i--)e the secondary yoke.

The invention will now be described in greater det-ail, 5 by way of example, wirh reference to the drawings, in wh i c h. - Figure 1 is a perspective view of one form of pivot joint in accordance with the invention as applied to the joint between primary and secondary yokes of a windscreen wiper blade harness; Figure 2 is a perspective view of the in f igure 1; joint body shown Figure 3 is a sectional view of tne joint taken on the line!I!-!!! of figure 1; Figure 4 is a side view of the pin used in the pivot 20 joint of figures 1 to 3; Figure 5 is a view similar to figure 4 but showing different form of pin; a Figure 6 is a view similar to figure 3 but showing a form of the joint in which the pin is provided with an annular groove; Figure 7 is a view similar zo figure 4 30 pin used in the joint shown in figure 6, and Figure 8 is a view similar to figure T 01-M 01 J.-.0 1 n T- 1 ri wn ich t he pin construction.

Referring to figure 1 of the. drawings, showing the 3 but showing a 1 G- 0 T sT. e pp e a there is shown a 1 1h pivot joint 1 between one end of the primary yoke 2 of the harness of a windscreen wiper blade and the secondary yoke 3, the joint being completed by a joinr body 5 lying mainly between the two yokes 2 and 3 and a and the joint 5 pin 6 passing through both yokes 2 and body 5. In The embodiment shown, it can be seen that the primary yoke is oi generally channel section having one wall 7 which is inclined outwardly from the base 8 of the channel-while the remaining wall 9 (figure 3) is at right angles to the channel base 8. The departure of-the primary yoke 2 from the usual channel section is determined by the particular characteristics of the blade which form no part of the present invention 1Der ke 3 is of the usual channel section se. The secondary yok to one side of the joint but is of the same section as the primary yoke on the other side where it forms an extension of the shape of' the main yoke 2. it will be seen that the dimensions of the secondary yoke 3P are such that, at the joint, it will sit within the channel oi the primary yoke 2, with sufficient clearance to permit the interposition or tne joint body 5.

The joint body 5 can be particularly seen from figures 2 and 3. it comprises-a generally channel shaped plastics moulding and is shaped exteriorly to enable it to fit snugly inside the cha nnel of the primary yoke I_. it has a shoulder 10 towards one end 11 against which the end 12 of the primary yoke sits and which provides a cover for the joint end, the outer contour of' this end portion 11 being shaped to continue the exterior surface of the primary yoke 2 into, as nearly as possible, the exterior surface of the secondary yoke 3. The remaining portion 14 is of reduced dimensions in order to seat wirhin zine channel of the primary yoke 2 and exhibits a pair of trunnions 15 and 16 which, while they are generally aligned for a purpose to be described hereafter, are 1 5 i J inclined to each other so t.-iat, when assembled to The primary yoke.9.. - they will extend at right ang-les to the respective side walls 7 and 9 thereof. in this posizion, they pass into apertures 19 and 20 in the primary YOKe 2 and their ends are preferably flush with the exterior surface of the primary yoke 2.

A bore 23 or 24 is formed in each of the trunnions 15 and 16 respectively, the bore 24 in the right hand trunnion 16 being coaxial with the trunnion 16 and the bore 23 in the left hand trunnion 15 being inclined to the axis of the trunnion!5 so as to be aligned with the other bore 24. These bores 23 and 24 are additionally aligned with a pair of ape-rtures 25 and 26 in the side walls of the secondary yoke 3 which, when assembled., lies within the channel of the joint body 5. The bore 23 in the left hand trunnion 15is formed with an annular groove 32.

The joint is completed by the pin 6, shown in figure 4 which may be of metal or plastics material. it is basically in the form of a plain cylindrical rod 30 with rounded ends 31 which has, towards one end, an annular projection or rib 28 whose position is intended to coincide with the position of the groove 32 in the bore 23 of the joint body 5. - The assembly of the pivot joint described above will now be considered:- The primary and secondary yokes 2 the appropriate apertures ig, 20, body 5 is rnouldea ana -rhe pin 6 step of the assembly is to push the channel of the primary yoke part 11 as a guide. The joint and 3 are formed with 25 and 26, The joint is formed. The first the joint body 5 into 2 using the enlarged body 5 is made of a sufficiently resilienr. plasTics joint body 5 is pushed into the yoke 2, the sides of the joint towards each other to allow the marerial TnaT,, as r.ne channel of the primary body 5 will be forced trunnions 15 and 16 to pass into the channel. Once the joint body 5 has been 1 pushed home, the sides will spring b a ck again, introducing the trunnions 15 and 16 into the respective apertures 19 and 20 in the primary yoke 2.

Then the secondary yoke 3 is offered up into the channel of the joint body b, in whicn lt is a sutT - icienziy loose fit to enable pivotting between the secondary yoke 3 and the joint body 5. At this po - int, the apertures 25 and 26 in the secondary yoke 3 will be in alignment with the bores 23 and 24 in the trunnions 15 and 16 of the joint body 5 and the pin tD can be pusned in. ine pin 6 May need to be actually forced in to enable its rib 28 to pass through the bores 23 in the itrunnionss, but once the rib 28 in 'the pin 6 is in alighmenz with the groove 32, the groove 32 will snap around the rib 26, locking the pin 6 in place and thus maintaining the joint.

it is to be observed that, with the arrangement shown, the secondary yoke 3 can pivot relative to the joint body 5 which itself will remain stationary with the primary yoke 2.

Figure 5 shows a variation of the pin which can be used with the above described joint. in this case, the pin 40 has a he;Ld 41 and an annular rib 4-2- towards the end away from the head 41. With this type of pin, the trunnion on the appropriate side may be cut back or countersunk To receive the he,=-t(l out x'his is nor Figure 6 shows a variation of the pivot joint shown in figures 1 to 3. in this form, the position of the rib 28 1 1 7 - and annular groove 32 are reversed so thaz the groove 32, is formed on the pin 6 and the rib 28 is formea on the wall of the bore 235 of ihe joint body 5. This makes for a slightly weaKer construction of the joint as a reduction in the diameter of the pin 6 is avoided. The pin 6 can be seen best from figure 7.

Figure 8 shows a further variation of the pivot joint shown in figures 1 to 3. in this case, the pin 50 used is of stepped formation 'Petween its ends, so that one part 52 is of larger diameter than the other part 53. Correspondingly, the bores 54 and 55 in the trunnions 15 and 16 are of different diameters. This makes for easier threading through of the pin 5Q and can make Tor easier alignment. The annular groove 57 can in fact be arranged in either part of t h e pin 50 with appropriate positioning of the rib 28 or vice versa.

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 trunnions could be of any other desired shape, such as oval or square since there 'is no need to enable any pivotting at this point. if desired, the shoulder 10 on the joint body could be omitted and aligned trunnions could be used, allowing the primary yoke to pivot relative to the joint body. Furthermore, in this latter case, the secondary yoke could then be maintained stationary with respect to the joint body by using a pin of non-circular cross section. I Where the rib is formed on the 1k, pin, Tnis need not be continuous but c-ould- be formed as a number of extending lugs, for example two. These lugs could be produced by forming pairs of indentations in the pin in such a way that the material of the pin is T orcea out 1 - 8 between the indentations.

it is to be understood that while the invention has been described as applicable to a primary yoke with one side wall inclined, -both walls could be inclined or both walls could be at right angles to the base of the channel.

While the invention has been described with particular reference to the harness of a windscreen wiper blade, it is to be understood that the invention is not limited to the windscreen wiper fiel.d but may also be applied to any situation in which a similar pivor j oint i S required.

1; A

Claims

1. A pivot. joint for pivotting together first. and second members, at least the first of T^fnich is of channel 5 section at the joint and the second of which is adapted to seat within the first, the pivot joint comprisingr a joint body of' generally channel section adapted to sit within the first member and to receive the second member therewithin, the joint body havinS a pair of outwardly 10 extending trunnions adapted to cooperate with apertures in the f irst member, aligned bores Through sald trunnions adapted to be aligned with alig.ned apertures in the second member, and a pin adapted to extend - the members and through the through the apertures ol bores of the trunnions of the joint body, the pin being retained in one of the bores of the joint body by means of one or more projections or recesses on zne pin cooperating with a respective recesses or projections in the bore.

IM, 1 I - io - A pivot joint comprising first and second members to be pivotted together, the first member being of channel section at!east. at the joint and the second member being adapted to seat within the channel section of the first member; a joint body of' generally channel section adapted to sit within the first member and to receive the second member within its channel section, the joint body having a pair of outwardly extending trunnions adapted to cooperate with apertures in the first member and aligned bores through said trunnions adapted to be aligned with aligned apertur es in the second member; and a pivot pin adapted to extend through the apertures of the members and through the bores of the trunnions of' the joint body, the pin being retained in one of the bores of the joint body by means of one or more projections or grooves on the pin cooperating witIn respective grooves or projections in the bore.

3. A pivot joint as claimed in claim 1 or 2, wherein a single projection is provided in the form of an annular rib-and the cooperating recess is an annular groove.

4. A pivot joint as claimed in any one of claims 1 to 3, wherein the pin is formed with the projection or projections and the bore is provided with the groove or grooves.

5. A pivot joint as claimed in any one of claims 1 to 4, wherein the pin is of stepped construction, being of larger diameter at one end than the other.

6. A pivot join,-. as claimed in any one of claims 1 to 55, wherein The members are YOKeS Ot a windscreen wiper harness.

1 4 1 J 1 1 4

7. A pivot joint as e.Lcaimp-a in claim 6, wherein the first member is the primary yoke of a windscreen wiper blade harness and the second member is the secondary yoke thereof.

8. A pivot joint substantially as descri. Ded herein with reference to the drawings, 4, 1 Publiblied 1988 at The Patent Office, State House, 86f7i High Holborn, London WC1R 4TP. Further copies may be obtained from The Patent Dmce, Sales Branch, St Mary Cray, Orpington, Kent BRS 3RD. Printed by Multiplex techniques ltd, St Mazr Cray, Kent. Con. 1/87.