IE921777A1

IE921777A1 - Pivot joints

Info

Publication number: IE921777A1
Application number: IE921777A
Authority: IE
Inventors: Peter James Harrison
Original assignee: Hardware & Systems Patents Ltd
Priority date: 1991-06-08
Filing date: 1992-07-01
Publication date: 1992-12-16
Also published as: GB9112370D0; IE66013B1; AU1802192A; GB2256453A; AU652450B2; GB2256453B; NZ243043A

Abstract

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 heads received in a countersink 10 in the arm 3. The rivet 2 is rotatable relative to the arm 3 and is secured against rotation relative to the base plate 4 by having a portion 7b of the shank 6 an interference fit in a through hole 11 in the base plate 4. The bush may be secured against rotation by the provision of a boss 16 and a complementary socket 17.

Description

This invention relates to pivot joints for stays adapted to mount a clos ure 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. -301 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 in uneven distribution of loads and stresses thereby adding to the risk of failure.

It is an object of the present invention to provide a pivot joint for stays which mitigates some of the problems and disadvantages aforementioned.

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 connecting first and second stay components, the fastening having a first shank portion located in a hole in the first component and a second shank portion of reduced cross-section located in an aligned hole in the second component, and a tail of the shank remote from the head being secured on the side of the second component remote from the first component.

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. -401 Preferably, the first and second shank portions are separated by a transverse abutment shoulder providing a stop face for engagement by the second component on securing the tail of the shank.

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 arrangement is particularly advantageous where the stay parts are made of stainless steel.

Advantageously, the first and second components are separated by 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 therebetween.

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

Preferably the co-operating formations are offset from the pivot axis and may comprise an integral projection such as a peg on the spacer that is received in an opening in the first component. -501 Advantageously, the first shank portion is located in a bushing of wear resistant selflubricating material received in the hole in the first component. In this way, contact between the first shank portion and the marginal edge of the hole in the first component is prevented.

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. In this way contact between the head of the fastening and side of the first component remote from the second component is prevented.

In a preferred construction, the bushing is formed integrally with the spacer thereby reducing the number of parts and simplifying assembly of the joint.

Preferably, the head of the fastening and/or 20 tail of the shank are located in respective countersinks in the first and second components.

The fastening may comprise a rivet with the tail of the shank being enlarged, for example by clinching, to prevent axial separation of the joint for maintaining the internal friction generated within the joint.

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

According to a second aspect of the invention, we provide a friction pivot joint -601 connecting first and second components of a stay for frictionally restrained relative movement comprising a spacer separating the components, a rivet having a head and a shank, the shank extending through aligned holes in the components and in the spacer, a bushing received in the hole in the first component between the shank and the marginal edge of the hole, the bushing having an axial length, prior to assembly, greater than the axial length of the hole whereby the outer end of the bushing is deformed under the head of the rivet on the side of the first component remote from the spacer for creating internal friction within the joint when a tail of the shank is secured on the side of the second component remote from the spacer, and the shank having abutment means for axially locating the second component on securing the tail of the shank.

Preferably, the abutment means comprises a transverse step or shoulder intermediate the ends of the shank providing a stop face for the second component.

Conveniently, the step or shoulder is provided between a first shank portion located in the bushing and a second shank portion of reduced cross-section located in the aligned hole in the second component.

Advantageously, the bushing is integral with the spacer and the spacer has means offset from the pivot axis for preventing rotation of the spacer relative to the first component.

According to a third aspect of the invention, we provide a pivot joint for a stay such as a -7Oi window stay comprising a headed fastening connecting first and second stay components, the fastening having a shank extending through aligned holes in the components and in a spacer separating the components with the head of the fastening located on the side of the first component remote from the spacer and a tail of the shank secured on the side of the second component remote from the spacer, and the spacer and first component having co-operating formations to prevent relative rotation therebetween.

By this third aspect of the invention, the first component is supported by the spacer for all positions of adjustment relative to the second component. As a result, loads and stresses to which the joint is subject in use are more evenly distributed thereby reducing the risk of failure.

Preferably, the co-operating formations are offset from the pivot axis and may conveniently comprise an opening in the first component for reception of an integral projection such as a peg on the spacer.

Advantageously, the spacer has an integral bush that is received in the hole in the first component and the shank of the fastening extends through the bush. In this way, contact between the shank and the marginal edge of the hole is prevented.

Preferably, the bush has an axial length, prior to assembly, greater than the axial length of the hole whereby the outer end of the bush is deformed under the head of the fastening on securing the tail of the shank. In this way -801 contact between the head and the first component is prevented.

Advantageously , the shank is adapted to locate axially the second component to control the internal friction generated within the joint on securing the tail of the shank.

Conveniently, the second component is axially located between the tail of the shank on one side and a stop face of the shank on the opposed side.

Preferably, the stop face is provided by a transverse shoulder or step in the shank.

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

According to a fourth aspect of the invention, we provide a pivot joint a for a stay such as a window stay comprising a headed fastening connecting first and second stay components, the fastening having a shank extending through aligned holes in the components with the head located on the side of the first component remote from the second component and a tail of the shank secured on the side of the second component remote from the first component, and the shank is an interference fit in the hole in the second component for securing the fastening against rotation relative to the second component.

By this fourth aspect of the invention, a separate member for locking the fastening against rotation relative to the second stay component is not required. As a result, assembly is facilitated reducing manufacturing costs. -901 Preferably, the portion of the shank received in the hole in the second component has axial ribs or like formations such that, during assembly, indentations are formed in the marginal edge of the hole by the ribs thereby locking the fastening relative to the second component. Alternatively, the axial ribs or like formations may be provided in the marginal edge of the hole in the second component and the indentations formed in the shank of the fastening during assembly.

According to a fifth aspect of the invention, we provide a stay such as a window stay having two components connected by a pivot joint according to any one of the first, second, third and fourth aspects of the invention.

The invention will now be described in more detail by way of example only, with reference to the accompanying drawing, wherein:Flgure 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 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 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 of the window. -100i 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 diameter defining a transverse step or 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 5.

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. -1 ιοί Prior to assembly of the joint 1, the bush 15 has an axial length greater than hole 9 such that the outer end projects into the countersink 10 for deformation under the rivet head 5 during assembly of the joint 1 as described later herein.

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 10 arm 4 to prevent relative rotation therebetween. The peg 16 has an axial length less than the opening 17 so that the outer end is recessed below the upper surface of the 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 arm 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 frustoconical 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 end of the bush 15 under the rivet head 5 until the transverse shoulder 8 seats against the base plate 4. -12Oi This deformation of 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 5 enabling the countersink 10 to be oversize providing a clearance gap between the marginal edge of the rivet head 5 and the wall of the countersink 10 to accommodate manufacturing tolerances and facilitate assembly.

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 the marginal edge of the hole 11 due to the interference fit therein of the 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 -13Oi avoiding separate means such as a lock washer for securing the rivet against rotation relative to the base plate.

The spacer 14 with integral bush 15 and peg Ιθ prevents metal-to-metal contact between the relatively 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.

It will be understood that the embodiment above-described is exemplary only of the invention and that various features are open to change or 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 formations 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 -1401 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 1° transverse shoulder and the rivet secured against rotation relative to the arm.

The invented pivot joint in each of its aspects as described herein has application to all types and constructions of stays for windows, doors and 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

Claims

1. θΐ Claims:1. A pivot joint for a stay such as a window stay comprising a headed fastening connecting first and second stay components, the fastening 05 having a first shank portion located in a hole in the first component and a second shank portion of reduced cross-section located in an aligned hole in the second component, and a tail of the shank remote from the head being secured on the side of 10 the second component remote from the first component.

2. A pivot joint according to Claim 1 wherein the second component is located on the second shank portion of reduced cross-section between the 15 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.

3. A pivot joint according to Claim 1 or Claim 2 20 wherein the first and second shank portions are separated by a transverse abutment shoulder providing a stop face for engagement by the second component on securing the tail of the shank.

4. A pivot joint according to any one of the 25 preceding Claims wherein the fastening is secured against rotation relative to the second component.

5. A pivot joint according to Claim 4 wherein the second shank portion is an interference fit in the hole in the second component to secure the 30 fastening against rotation.

6. A pivot joint according to Claim 5 wherein the second shank portion has axial ribs or like formations for locking engagement with the marginal edge of the hole In the second component. -167. A pivot joint according to any preceding Claim wherein the first and second components are separated by a spacer of wear resistant selflubricating material such as nylon preferably located on the first shank portion.

7. 8. A pivot joint according to Claim 7 wherein the spacer is secured against rotation relative to the first component.

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

9. 10. A pivot joint accordin to Claim 9 wherein the co-operating formations are offset from the pivot axis and comprise an integral projection such as a peg on the spacer that is received in an opening in the first component.

10. 11. A pivot joint according to any one of Claims 7 to 10 wherein the first shank portion is located in a bushing of wear resistant selflubricating material received in the hole in the first component.

11. 12. A pivot joint according to Claim 11 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. 13. A pivot joint according to Claim 11 or Claim 12 wherein the bushing is formed integrally with the spacer.

13. 14. A pivot joint according to any preceding Claim wherein the head of the fastening and/or -17Oi tail of the shank are located in respective countersinks in the first and second components.

14. 15. A pivot joint according to any preceding Claim wherein the fastening comprises a rivet with 05 the tail of the shank being secured to prevent axial separation of the joint for maintaining the internal friction generated within the joint.

15. 16. A pivot joint according to any preceding Claim wherein the stay components comprise an arm 10 and a base plate for securing to a closure or surrounding frame.

16. 17. A pivot joint according to Claim 16 wherein first component comprises the arm and the second component comprises the base plate. 15

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

18. 19. A friction pivot joint connecting first and second components of a stay for frictionally

19. 20 restrained relative movement comprising a spacer separating the components, a rivet having a head and a shank, the shank extending through aligned holes in the components and in the spacer, a bushing received in the hole in the first 25 component between the shank and the marginal edge of the hole, the bushing having an axial length, prior to assembly, greater than the axial length of the hole whereby the outer end of the bushing is deformed under the head of the rivet on the 30 side of the first component remote from the spacer for creating internal friction within the joint when a tail of the shank is secured on the side of the second component remote from the spacer, and -1801 the shank having abutment means for axially locating the second component on securing the tail of the shank. 20. A pivot joint according to Claim 19 wherein 05 the abutment means comprises a transverse step or shoulder intermediate the ends of the shank providing a stop face for the second component.

20. 21. A pivot joint according to Claim 20 wherein the step or shoulder is provided between a first 10 shank portion located in the bushing and a second shank portion of reduced cross-section located in the aligned hole in the second component.

21. 22. A pivot joint according to Claim 21 wherein the second shank portion is an interference fit in 15 the hole in the second component for preventing rotation of the rivet relative to the second component.

22. 23. A pivot joint according to Claim 22 wherein the second shank portion has axial ribs or like 20 formations for engagement with the marginal edge of the hole in the second component to prevent relative rotation therebetween.

23. 24. A pivot joint according to any one of Claims 19 to 23 wherein the bushing is integral

24. 25 with the spacer. 25. A pivot joint according to any one of Claims 19 to 24 wherein the spacer has means offset from the pivot axis for preventing rotation of the spacer relative to the first component. 30

25. 26. A pivot joint for a stay substantially as hereinbefore described with reference to the accompanying drawing. -1901

26. 27. A stay for a window, door or the like having at least one pivot joint according to any one of the preceding Claims.

27. 28. A rivet for a friction pivot joint according 05 to any one of the preceding Claims comprises a tubular member having a head and a shank, the shank having an abutment face intermediate the head and a tail of the shank remote from the head for axially locating the rivet relative to one of 1° two stay components coupled by the rivet.

28. 29. A rivet according to Claim 28 wherein the abutment face is provided between a first shank portion extending from the underside of the head and a coaxial second shank portion of reduced 15 cross-section.

29. 30. A rivet according to Claim 29 wherein the second shank portion is adapted to be an interference fit in a hole in said one stay component. 20

30. 31. A rivet according to Claim 30 wherein the second shank portion has axial ribs or like formations for locking the rivet against rotation relative to said one stay component.

31. 32. A rivet for a friction pivot joint 25 substantially as hereinbefore described with reference to the accompanying drawing.

32. 33. A method of controlling the internal friction in a pivot joint connecting two components of a stay for relative movement comprises providing a 30 fastening having a head and a shank, locating the shank in aligned holes in the components and securing a tail of the fastening remote from the head to locate a step intermediate the ends of the -2001 shank against the component remote from the head to limit the load applied to a bearing material within the joint to generate the required internal friction. 05

33. 34. A method according to Claim 33 wherein the bearing material is deformed under the head of the fastening during assembly.

34. 35. A method according to Claim 33 or Claim 34 wherein the shank is adapted to be an interference 10 fit in a through hole in said component remote from the head.

35. 36. A rivetted pivot joint connecting first and second stay parts for frictionally restrained pivotal movement has its internal friction 15 controlled during assembly by engagement of an abutment face intermediate the ends of the rivet shank with one of the stay parts.

36. 37. A rivetted pivot joint according to Claim 36 wherein the internal friction is generated by 20 deformation of bearing material, preferably a self-lubricating wear resistant material such as nylon or the like, under the rivet head.

37. 38. A rivetted pivot joint according to Claim 37 wherein the stay parts are separated by a spacer 25 having an integral bush received in a through hole in the other stay part with the bush having an axial length prior to assembly greater than the hole whereby the free end of the bush is deformed under the rivet head during assembly to generate 30 the internal friction.

38.

39. A rivetted pivot joint according to any one of Claims 36 to 38 wherein the rivet shank is an interference fit in a through hole in said one stay part for preventing rotation of the rivet 35 thereto.