AU652450B2

AU652450B2 - Pivot joints

Info

Publication number: AU652450B2
Application number: AU18021/92A
Authority: AU
Inventors: Peter James Harrison
Original assignee: Hardware and Systems Patents Ltd
Current assignee: Hardware and Systems Patents Ltd
Priority date: 1991-06-08
Filing date: 1992-06-04
Publication date: 1994-08-25
Anticipated expiration: 2012-06-04
Also published as: GB2256453B; GB9112370D0; IE921777A1; IE66013B1; NZ243043A; AU1802192A; GB2256453A

Description

;r 652450

AUSTRALIA

Patents Act 1990 P/00/0011 Regulation 3.2 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

000000 0 00 0 0 0 0000 0 .0 0 00 0 00 0 0 00 000000 Name of Applicant: HARDWARE SYSTEMS PATENTS LIMITED Actual Inventor(s): Peter James HARRISON Address for service in Australia: 0 r 00 0000 0 00 00 0 0 0000 0006 0 D 0000 110 0 000 0000 0000 CARTER SMITH BEADLE Qantas House 2 Railway Parade Camberwell Victoria 3124 Australia Attorney Code CD Invention Title: PIVOT JOINTS The following statement is a full description of this invention, including the best method of performing it known to us: Our Ref: #10732 DCC:WB 05-20har ii This invention relates to pivot joints for stays adapted to mount a closure member on a surrounding frame for movement relative to the frame and in particular, though not exclusively, to friction pivot joints for window stays.

Window stays incorporating one or more friction pivot joints by means of which the window is held in any desired open position by internal friction within the pivot joint(s) are known.

The known friction pivot joints commonly employ a fastener such as a rivet coupling two stay components such as arms, links or mounting plates so as to generate internal friction within the joint.

It is necessary to avoid metal-to-metal contact between relatively movable parts of the pivot joint which could give rise to wear with consequential loss of friction and it is known to incorporate spacers of wear resistant material such as plastics within the joint for this purpose.

The window stays with such friction pivot joints are commonly employed in pairs arranged on opposed sides of the window for top, bottom or side opening. The friction pivot joints are subjected in use to high loads and stresses due to the heavy weight of the glazed sash, strong winds, and temperature changes. Additionally, the friction pivot joints are commonly exposed in use to weathering, dirt and other contamination. All of this increases the risk of failure in use and places limitations on the design and materials that can be used for the various parts.

Other problems can arise where similar stays are not matched due to variations in the geometry and/or internal friction of the pivot joints resulting 25 in uneven distribution of loads and stresses thereby adding to the risk of failure.

Ca 94 9 o 9, 0 49 a 0 *a 92 G0 94 044 a It is an object of the present invention to provide a pivot joint for aaoo stays which mitigates some of the problems and disadvantages aforementioned.

30 According to a first aspect of the invention, we provide a pivot joint for a stay such as a window stay comprising a headed fastening having a :shank extending through aligned holes in first and second stay components a° with a tail of the shank remote from the head being secured on the side of the second component remote from the first component to connect pivotally the components and apply friction creating pressure within the joint, the shank having a first portion located in the hole in the first component, a a cv,2 P i h.-i

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second portion of reduced cross-section located in the aligned hole in the second component, and a shoulder between the first and second portions for locating the second component and controlling the friction on securing the tail of the shank, and bearing material within the joint between the first and second components and between the first component and the fastening.

By this.first aspect of the invention, the internal friction generated within the joint on securing the tail of the shank is controlled by axial location of the second component on the shank.

More particularly, the second component is located on the second shank portion of reduced cross-section between the tail of the shank and the first shank portion thereby limiting the axial pressure that can be applied to the fastening on securing the tail to generate the internal friction within the joint. As a result, a uniform level of internal friction is consistently obtained.

Preferably, the fastening is secured against rotation relative to the second component to prevent wear. In a preferred construction, the second shank portion is an interference fit in the hole in the second component to secure the fastening against rotation. Conveniently, the second shank portion has axial ribs or like formations such that, during assembly, indentations are formed in the marginal edge of the hole in the second component by the ribs thereby locking the fastening against rotation. This oo arrangement is particularly advantageous where the stay parts are made of 0444 stainless steel.

0 Advantageously, the bearing material between the first and second ~25 components comprises a spacer of wear resistant self-lubricating material such as nylon preferably located on the first shank portion. In this way contact between the components is prevented for relative rotation o. therebetween.

oPreferably, the spacer is secured against rotation relative to the first 30 component. For example, the spacer and first component may have co- 0 .0 0 operating formations for preventing relative rotation therebetween.

0 00 So.o Conveniently, the co-operating formations are offset from the pivot axis and 9 o may comprise an integral projection such as a peg on the spacer that is received in an opening in the first component.

,5 Advantageously, the bearing material between the first component Sand the fastening comprises a bushing of wear resistant self-lubricating is- T 4 j-4; i i 1 i :z material such as nylon received in the hole in the first component and extending under the head of the fastening. In this way, contact between the first component and the fastening is prevented for relative rotation therebetween.

Preferably, the bushing has an axial length prior to assembly, greater than the axial.length of the hole in the first component such that the outer end of the bushing is deformed under the head of the fastening on securing the tail of the shank. In a preferred construction, the bushing is formed integrally with the spacer thereby reducing the number of parts and simplifying assembly of the joint.

The fastening may comprise a rivet with the tail of the shank being enlarged, for example by clincling, to prevent axial separation of the joint for maintaining the internal friction generated within the joint. Preferably, the head of the fastening and/or tail of the shank are located in respective countersinks in the first and second components.

The stay components may comprise an arm and a base plate or a pair of arms for securing to a closure or surrounding frame respectively. In a preferred construction, the first component is an arm and the second component is a base plat-.

The invention will now be described in more detail by way of example only, with reference to the accompanying drawing, wherein:- FIGURE 1 is a cross-section through a pivot joint according to the present invention; and FIGURE 2 is an exploded isometric view of the component parts of 25 the pivot joint shown in Figure 1.

The pivot joint 1 shown in the drawing has a tubular rivet 2 coupling first and second components 3 and 4 respectively of a window stay for frictionally restrained relative movement. The components 3,4 are made of stainless steel but other metals or alloys may be used for one or both stay 30 components 3,4. In this embodiment, the components 3,4 comprise an arm 3 pivotally connected at one end to a base plate 4 for mounting on one of a sash and fixed frame oi the window.

The rivet 2 has a head 5 and a shank 6. The shank 6 has a cylindrical first portion 7a extending from the underside of the head 5 and a coaxial second portion 7b of reduced diamter defining a transverse step or *0 0 0 0 o 0o 4 0 0 a0 4, 0 0 00 0 0 0;ut 008 0000 00.o 0 0

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shoulder 8 constituting abutment means intermediate the ends of the shank 6 for controlling the internal friction as described later herein.

The arm 3 has a cylindrical through hole 9 for reception of the first shank portion 7a with radial clearance and a coaxial cylindrical countersink 10 on the side remote from the base plate 4 for reception of the rivet head The base plate 4 has a cylindrical through hole 11 aligned with the hole 9 for reception of the second shank portion 7b and a coaxial frustoconical countersink 12 on the underside remote from the arm 3 in which the tail 13 of the shank 6 is secured on assembly of the joint 1 as described later herein.

The second shank portion 7b is an interference fit in the hole 11 and has axial ribs 7c for securing the rivet 2 against rotation relative to the base plate 4 on assembly of the joint 1 as described later herein.

The arm 3 and base plate 4 are separated by a spacer 14 of wear resistant self-lubricating material such as nylon for rotation of the arm 3 relative to the base plate 4.

The spacer 14 has an integral cylindrical bush 15 on one side that is received in the radial clearance between the first shank portion 7a and the marginal edge of the hole 9 for rotation of the rivet 2 relative to the arm 3.

Prior to assembly of the joint 1, the bush 15 has an axial length o greater ihan hole 9 such that the outer end projects into the countersink ifor deformation under the rivet head 5 during assembly of the joint 1 as o described later herein.

25 Offset from the pivot axis X, the spacer 14 has an integral cylindrical peg 16 spaced from and on the same side as the bush 15 that is received in a complementary cylindrical opening 17 in the arm 4 to prevent relative 004J rotation therebetween. The peg 16 has an axial length less than the a °opening 17 so that the outer end is recessed below the upper surface of the 0 0 arm 3.

To assemble the pivot joint 1, the spacer 14 is located on the underside of the arm 3 so that the bush 15 is received in the hole 9 with the outer end projecting into the countersink 10 and the peg 16 is received in the opening 17.

Next, the hole 9 with the bush 15 therein is aligned with the hole 11 in the base plate 4 and the rivet shank 6 inserted from the upper surface of the

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-6arm 3 to locate the first shank portion 7a in the bush 15 and the second shank portion 7b in the hole 11.

The tail 13 of the shank 6 is then enlarged by clinching or swaging to engage the frusto-conical countersink 12 in the base plate 4 thereby drawing the rivet head 5 into the countersink 10 in the arm 3 and deforming the outer enJ of the bush 15 under the rivet head 5 until the transverse shoulder 8 seats against the base plate 4.

This deformation ot the bush 15 creates internal friction within the joint 1 that is maintained by the clinched tail 13 of the shank 6 preventing axial separation of the joint 1. A further contribution to maintaining the internal friction may also be provided by the countersink 10 which retains the deformed bush 15 reducing creep.

As will be understood, the transverse shoulder 8 provides abutment means for axially locating the base plate 4 between the first shank portion 7a and the clinched tail 13 of the shank 6 for limiting the axial pressure applied to the rivet to control the deformation of the bush 15. As a result, pivot joints 1 having a- uniform level of internal friction can be consistently obtained enabling similar stays to be matched.

A further advantage of controlling the deformation of the bush 15 is that the material of the bush 15 can be confined below the rivet head enabling the countersink 10 to be oversize providing a clearance gap I "o between the marginal edge of the rivet head 5 and the wall of the countersink 10 to accommodate manufacturing tolerances and facilitate o o assembly.

0 04 i..oo 25 The rivet 2 is locked against rotation relative to the base plate 4 during assembly of the joint 1 by the axial ribs 7c which form indentations in ,o the marginal edge of the hole 11 due to the interference fit therein of the r second shank portion 7b and in the surface of the base plate 4 around the hole 11 when the tail 6 is clinched. As a result, assembly is facilitated by f, 30 avoiding separate means such as a lock washer for securing the rivet 0°o,0 against rotation relative to the base plate.

0o 0 The spacer 14 with integral bush 15 and peg 16 prevents metal-to- 0 0° metal contact between the relatiyely rotatable elements of the joint 1 and is rotatable with and supports the arm 3 relative to the base plate 4. As a result, wear is lessened and loads and stresses are more evenly distributed thereby reducing the risk of failure in service.

1 i t Il :a- It will be understood that the embodiment above-described is exemplary only of the invention and that various features are open to change of modification within the scope of the various aspects of the invention as described herein.

For example, the bush may be formed separately from the spacer and may be deformed under the rivet head or provided with an integral flange that is compressed below the rivet head to generate the internal friction.

The spacer may be secured against rotation relative to the arm by any suitable means such as integral flanges on opposed sides for engagement with opposed sides of the arm.

The axial ribs on the rivet shank may be replaced by any other suitable formations for securing the rivet against rotation relative to the base. The axial ribs or like formation, may be provided in the marginal edge of the hole of the base plate so as to form indentations in the rivet shank for locking the rivet against rotation relative to the base plate.

Alternatively, any other suitable means for locking the rivet against rotation relative to the base plate may be provided as known to those skilled in the art.

The rivet may be replaced by a fastening having a shank with a threaded tail for reception of a nut to secure the joint.

The arm and base plate may be reversed so that the arm is axially located on the rivet or similar fastening by engagement with the transverse shoulder and the rivet secured against rotation relative to the arm.

The spacer is sandwiched between the two stay parts connected by the pivot joint and has flat bearing surfaces on opposed sides for engagement with the confronting surfaces of the two stay parts so as to spread uniformly the loads and avoid slackness in the joint when the stay parts are secured to generate the internal friction.

The invented pivot joint as described herein has application to all 30 types and constructions of stays for windows, doors or the like closures in which the joint connects two relatively movable components of the stay such as an arm and a base plate or a pair of arms.

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-9- A pivot joint according to any one of the preceding Claims wherein the bearing material between the first component and the fastening comprises a bushing of wear resistant self-lubricating material received in th6 hole in the first component and extending under the head of the fastening.

11. A pivot joint according to Claim 10 wherein the bushing has an axial length, prior to assembly, greater than the axial length of the hole in the first component such that, during assembly, the outer end of the bushing is deformed under the head of the fastening.

12. A pivot joint according to Claim 10 or Claim 11 as dependent on any one of Claims 5 to 9 wherein the bushing is formed integrally with the spacer.

13. A pivot joint according to any one of the preceding Claims wherein the bearing materili comprises nylon or like wear resistant self-lubricating material.

14. A pivot joint according to any one of the preceding Claims wherein the head of the fastening and/or tail of the shank are located in respective countersinks in the first and second components.

A pivot joint according to any one of the preceding Claims wherein the fastening comprises a rivet with the tail of the shank being secured to prevent axial separation of the joint for maintaining the internal friction 0o generated within the joint.

S16. A pivot joint according to any one of the preceding Claims wherein tna 0406 0 the stay components comprise an arm and a base plate for securing to a 25 closure or surrounding frame.

17. A pivot joint according to Claim 16 wherein first component comprises o the arm and the second component comprises the base plate.

18. A pivot joint according to any one of Claims 1 to 15 wherein the stay S, components comprise a pair of arms.

00 0 30 19. A pivot joint substantially as hereinbefore described with reference to 0 0the accompanying drawing.

o 20. A stay for a window or door having two components pivotally connected together by the pivot joint according to any one of the preceding Claims.

Claims

1. A pivot joint for a stay such as a window stay comprises a headed fastening having a shank extending through aligned holes !n first and second stay components with a tail of the shank remote from the head being secured on the side of the second component remote from the first component to connect pivotally the components and apply friction creating pressure within the joint, the shank having a first portion located in the hole in the first component, a second portion of reduced cross-section located in the aligned hole in the second component, and a shoulder between the first and second portions for locating the second component and controlling the friction on securing the tail of the shank, and bearing material within the joint between the first and second components and between the first component and the fastening.

2. A pivot joint according to Claim 1 wherein the fastening is sec- ed against rotation relative to the second component.

3. A pivot joint according to Claim 2 wherein the second shank portion is an interference fit in the hole in the second component to secure the fastening against rotation.

4. A pivot joint according to Claim 3 wherein the second shank ,,Ifion has axial ribs or like formations for locking engagement with the marginal edge of the hole in the second component.

5. A pivot joint according to any one of the preceding Claims wherein the bearing material between the first and second components comprises a spacer of wear resistant self-lubricating material locatled on the first shank 25 portion.

6. A pivot joint according to Claim 5 wherein the spacer has substantially flat bearing surfaces on opposed sides for engagement with the confronting surfaces of the stay components.

7. A pivot joint according to Claim 5 or Claim 6 wherein the spacer is 30 secured against rotation relative to the first component.

8. A pivot joint according to Claim 7 wherein the spacer and first component have co-operating formations for preventing relative rotation therebetween.

9. A pivot joint according to Claim 8 wherein the co-operating formations 35 are offset from the pivot axis and comprise an integral projectik)n such as a peg on the spacer that is received in an opening in the first if lnent. 4 0 4 44r *s 4 0 4 4 0 *O o 0IP 4 04

44. 4444 0444 4 44O 49 0 F 4 'A r. P 1, e r i t! 1 1 1 i -i. 21. A stay for a window or door having a rivet pivotally connecting first and second stay components for frictionally restrained relative movement wherein the rivet has a head and a shank with a shoulder between shank portions of greater and lesser diameter, the first component being located on the shank portion of greater diameter with the rivet head on the side of the first component remote from the second component, the second component being located on the shank portion of lesser diameter vith the shoulder engaging the second component to control the internal friction created within the joint when a tail of the shank is secured on the side of the second component remote from the first component to connect pivotally the components, and bearing material within the joint between the first and second components and between the first component and the rivet. DATED: 28 June 1994 CARTER SMITH BEADIE Patent Attorneys for the Applicant: HARDWARE SYSTEMS PATENTS LIMITED 1 4 0 I l I 41 0 01 o ,4 ii I 01 Abstract: PIVOT JOINT A rivetted pivot joint 1 connecting an arm 3 and a base plate 4 of a window stay for frictionally restrained pivotal movement has its internal friction controlled during assembly by engagement of an abutment face 8 intermediate the ends of the rivet shank 6 with the base plate 4 to limit the deformation of a bush 15 under the rivet 10 head 5 received in a countersink 10 4 n the arm 3. o S The rivet 2 is rotatable relative to the arm 3 and °o is secured against rotation relative to the base o plate 4 by having a portion 7b of the shank 6 an t oo interference fit in a through hole 11 in the base plate 4. SFigure 1. 03.* 0 0