NZ573233A

NZ573233A - A friction pivot joint and window stay

Info

Publication number: NZ573233A
Application number: NZ57323308A
Authority: NZ
Inventors: Paul Davis
Original assignee: Fmi Res Ltd
Priority date: 2008-11-27
Filing date: 2008-11-27
Publication date: 2010-03-26
Also published as: AU2009240862B2; AU2009240862A1

Abstract

An arm 4, typically for supporting a pivoted window sash, is pivotally connected typically to a frame or sash plate 1 via a pivot bearing formed from an annular boss 6 of arm 4 being located within aperture 9 of plate 1. Arm 1 has an annular wall surrounding aperture 9 which projects inwardly then turns at an annular step to terminate as a generally cylindrical portion. A wear resistant plastic bush has a sleeve 7 located between aperture 9 and boss 6 and a flange 8 placed within the bearing and the free end of the boss is pressed over to form the bearing.

Description

<div class="application article clearfix" id="description"> 573233 *10058457099* No: 573233 Date: 27 November 2008 NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION A PIVOT JOINT We, FMI RESEARCH LIMITED, a company duly incorporated under the laws of New Zealand of 6 Titnaru Place, Mt Wellington, Auckland, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 - RECEIVED at IPONZ on 25 February 2010 5732^3 FIELD OF INVENTION The invention relates to a pivot bearing, preferably of a friction type, for use pivotally coupling two components such as in a window stay. 5 BACKGROUND Window stays commonly incorporate friction pivot bearings. After a high number of operations the level of friction provided by the bearings may reduce to be insufficient to hold the window 10 sash in position when opened. It is an object of the invention to provide an improved or at least alternative friction pivot bearing that maintains friction over an extended number of open and close operations. SUMMARY OF INVENTION 15 In broad terms the invention comprises an item including at least first and second metal components pivotally coupled together by a pivot bearing, the pivot bearing comprising a hollow annular boss formed by having been drawn from the material of the second component as an integral part of the second component, the annular boss having a free end and an outer wall 20 surface forming a bearing surface, an opening in the first component and an annular wall around the opening which projects inwardly from the periphery of the opening and then turns at an annular step to terminate in a generally cylindrical portion, the annular boss being located within said opening so that the first and second components are relatively rotatable, a wear resistant plastic bushing positioned within the bearing and comprising a sleeve and a flange, the sleeve 25 being located between the annular boss and the opening and the flange between the first and second components, the free end portion of the boss being pressed over to close the joint. The item may be a window stay in which arms of the window stay are pivotally coupled to sash and frame mounting plates via pivot bearings of the invention, or may be any other item such as 30 for example a rcstrictor stay connected between a window frame and sash to limit the angle of opening of the window sash and comprising arms coupled by pivot bearings of the invention. 5732^3" In some embodiments the free end portion of the boss is pressed over to close the joint with said bushing under sufficient pressure to create friction within the bearing. In other embodiments the free end portion of the boss is pressed over to close the joint but without significant friction-creating pressure in the bearing. 5 The term 'comprising' as used in this specification means 'consisting at least in part of, that is to say when interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. 10 BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment is further described with reference to the accompanying figures, by way of example only and without intending to be limiting, wherein; 15 Figure 1A and IB are plan views of a four bar window stay incorporating pivot bearings of the invention, in an open and a closed position respectively; Figure 2 is a cross-section view of one of the pivot bearings of the window stay along line A-A of Figure 1A; and 20 Figures 3A-3C show various elements of the pivot bearing in cross-section before assembly and Figure 3D is a view similar to Figure 2 of the assembled joint. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 25 The window stay of Figures 1A and IB consists of sash and frame mounting plates 1 and 2 and two arms 3 and 4 which are coupled at each end to the plates 1 and 2 via friction pivot bearings 5, one or more of which are of the form further described. Figure 1A shows the window stay open and Figure lb shows the window stay closed. 30 Figure 2 is a cross-sectional view through a pivot bearing 5, along line A-A in Figure IB. A hollow annular boss 6 is formed as an integral part of the arm 4, by being drawn from the arm material. The annular boss 6 can be formed by establishing a small hole in the arm that determines the centre of the resultant pivot bearing, and then drawing metal from around the 5732fc} hole to form the boss. Figure 3A shows the arm 4 and annular boss 4 before assembly and closing of the joint. Typically, if the arm is of uniform thickness the resultant annular boss 6 will have a cross sectional wall thickness which is less than that of the arm from which it is drawn. 5 A plastic bushing comprising a sleeve 7 and a flange 8 is formed from of for example Nylon or other wear resistant plastics material. The sleeve 7 is located over the annular boss 6 so that the flange 8 lies against the surface of the arm 4. The plate 1 is formed with an opening 9. The plate 1 and arm 2 are brought together so that the annular boss 6 and the sleeve 7 extend through the opening 9, with the flange 8 of the sleeve sitting between to prevent metal to metal contact and 10 create friction between the arm and plate. Material of the plate 1 around the opening 9 forms an annular wall lOa/lOb around the opening on one side of the plate 1, which projects annularly inwardly around the periphery of the opening 9 and then turns at annular step 11 to terminate in a generally cylindrical portion 12. In 15 the preferred form the annular wall lOa/lOb comprises portion 10a which extends more away from the plate than across the aperture 9 and portion 10b which extends more across the aperture. In an alternative form however the annular wall may extend inwardly across the aperture 9 from the periphery of the aperture to the portion 12 at a fixed angle of for example 20-70 degrees to the plane of the plate 1. The free end 13 of the annular boss 6 is swaged or 20 pressed over to close against the under-side of the annular wall lOa/lOb and step 11, and create friction in the joint. Also the annular wall lOa/lOb and step 11 and the cylindrical portion 12 of the peripheral wall surface 10 exposes a relatively large surface area of the first component 1 to the plastic bushing which increases friction in the bearing, so that the joint will have a longer lifetime. 25 Figure 3A shows the annular boss 6 formed in the arm 4 before assembly and closing of the joint. A punch and die set may be employed to form the boss 6. The length of the boss 6 is such that once the joint is closed, the free end of the boss does not extend past the lower edge or surface of the plate 1. 30 Figure 3B shows the plastic bushing 14 or friction pad before assembling the joint, which comprises a sleeve 7 and a flange 8. The plastic bushing 14 has a diameter so that it can fit over the boss 6 during assembly. The flange 8 is shaped to accommodate and surround some of or the entire outer surface 15 of the peripheral wall of the opening 9 in the arm 1. The sleeve 7 5732$3- when pressed over with the boss accommodates and surrounds some of or the entire inner surface of the peripheral wall of the opening 9 in the first component 1. Figure 3C shows the plate 1 before assembling the joint. At assembly the plastic bushing 14 is 5 inserted through the opening 9 in the first component 1, the boss 6 of the second component is inserted through the bushing 14, to the assembly state shown in Figure 3D. Then the boss 6 pressed over to the form shown in Figure 2 in a machine press. The increased surface area exposure between the first and second components 1 and 4 and the plastic bushing 14 ensures increased friction within the closed joint. In other embodiments however the free end portion of 10 the boss is pressed over to close the joint but without significant friction-creating pressure in the bearing, to provide a substantially frictionless joint. In the embodiment described above the item is a window stay in which arms of the window stay are pivotally coupled to sash and frame mounting plates via pivot bearings of the invention. In a 15 window stay the joints of the invention may provide the window stay with longer life and in particular the stay may maintain its pull-in at closing, between the head of the window sash and the window frame, for a longer life of the window stay. In alternative embodiments the friction or frictionless pivot joints of the invention may be used in any other item such as for example a restrictor stay connected between a window frame and sash to limit the angle of opening of the 20 window sash and comprising arms coupled by pivot bearings of the invention. The foregoing describes the invention including a preferred form thereof. Alterations and modifications as would be obvious to those skilled in the art are intended to be incorporated in the scope hereof as defined in the accompanying claims. 25 RECEIVED at IPONZ on 25 February 2010 5732^3 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> CLAIMS:

1. An item including at least first and second metal components pivotally coupled together by a pivot bearing, the pivot bearing comprising a hollow annular boss formed by having been 5 drawn from the material of the second component as an integral part of the second component, the annular boss having a free end and an outer wall surface forming a bearing surface, an opening in the first component and an annular wall around the opening which projects inwardly from the periphery of the opening and then turns at an annular step to terminate in a generaEy cylindrical portion, the annular boss being located within said opening so that the first and 10 second components are relatively rotatable, a wear resistant plastic bushing positioned within the bearing and comprising a sleeve and a flange, the sleeve being located between the annular boss and the opening and the flange between the first and second components, the free end portion of the boss being pressed over to close the joint. 15

2. An item according to claim \ wherein the free end portion of the boss is pressed over to close the joint with said bushing under sufficient pressure to create friction within the bearing.

3. An item according to claim 1 wherein said annular wall around the opening which projects inwardly around the periphery of the opening comprises a first annular wall portion which 20 extends more away from the first component than across the aperture and a second portion which extends more across the aperture than away from the second component before terminating in said generally cylindrical portion.

4. A window stay for mounting a sash in a window frame and including at least first and 25 second metal components pivotally coupled together by a pivot bearing, the pivot bearing comprising a hollow annular boss formed by having been drawn from the material of the second component as an integral part of the second component, the annular boss having a free end and an outer wall surface forming a bearing sutfacc, an opening in the first component and an annular wall around the opening which projects inwardly from the periphery of the opening and 30 then turns at an annular step to terminate in a generally cylindrical portion, the annular boss being located within said opening so that the first and second components are relatively rotatable, a wear resistant plastic bushing positioned within the bearings and comprising a sleeve and a flange, the sleeve being located between the annular boss and the opening and the flange between the first and second components. RECEIVED at IPONZ on 25 February 2010 5732^3

5. A window stay according to claim 4 wherein the free end portion of the boss is pressed over to close the joint with said bushing under sufficient pressure to create friction within the bearing. 5

6. A window stay according to any one of claims 4 to 6 wherein said annular wall around the opening which projects inwardly around the periphery of the opening comprises a first annular wall portion which extends more away from the first component than across the aperture and a second portion which extends more across the aperture than away from the second component 10 before terminating in said generally cylindrical portion.

7. A window stay according to any one of claims 4 to 7 wherein the first component is the base plate of the window stay and the second component is an arm of the window stay. 15

8. A window stay according to any one of claims 4 to 8 and wherein each pivot joint of the window stay is as defined therein.

9. A window stay including at least one pivot joint substantially as described herein with reference to Figure 2. 20 </div>