GB2083129A - Improvements in stays for windows - Google Patents

Abstract

A friction stay for windows having arms or links and mounting plates pivotally connected together by rivetted friction joints, the stay parts at the pivot joint are coated with a low friction plastics material of thickness from 0.003" to 0.018". By such coating, the risk of wear and other problems of metal interface engagement are avoided.

Description

SPECIFICATION Improvements in stays for windows This invention concerns improvements in stays suitable for windows. In particular, stays which are called friction stays and of the kind comprising one or more arms or links and/or mounting plates (such arms, links or plates herein also called stay parts) that are connected together by one or more friction pivot joints which permit restrained pivotal move ment of the stay parts, the stay being adapted and arranged for mounting on a sash and securing to the associated frame so that the sash is supported for frictionally restrained movement on and relative to the frame.

Such stays of the kind specified are conventionally used in pairs, one each side of the sash and associated frame. The sash may be hung on the stays for top, bottom or side opening. The frictional restraint to maintain the sash in an adjusted position is provided in the pivot joints by suitable design and manufacture of the pivot joints.

The pivot joints are usually provided by rivets which extend through the stay parts with the rivet being clinched in a manner to generate forces which, after clinching, provide the frictional restraint.

The operation of the stay when fitted in a window must be smooth and wear of the pivot joint and corrosion must be avoided. It has been proposed previously to fit a self-lubricating bushing or washer under the head of the rivet to provide for the smooth operation, and such bushing, if made of suitable plastics material can assist in corrosion resistance.

However, the shank of the rivet is not so protected and there is a risk of metal to metal contact and resultant wear or inter-metallic reactions on weath ering.

The use of plastics washers leads to other prob lems in manufacture of such stays for plastics materials suitable for use in such applications have a characteristic of deforming under loads so that the washer or bushing spreads both under the high clinching pressures and the residual pressures in the pivot joint. Thus, it has been found essential to confine the washer or bushing in a recess which extends in the stay part underneath the head of the rivet. Such recess confines the washer or bushing against such deformation. However, the provision of the recess, usually a counter-bore, increases manu facturing costs. Additionally, whilst the recess in the stay part has to be provided, the stay part must be made of material having sufficient thickness and strength for service and the recess effectively weakens the section.This leads to the use of materials which to a large extent are thicker than would be required if the recess were not there.

According to this invention, we provide a friction stay of the kind defined wherein the surfaces of the stay parts at least adjoining and extending in the pivot joint are coated with a low friction plastics material by a powder coating technique with the coating having a thickness from 0.003" to 0.018".

By providing such a plastics coating the stay parts are provided with low friction surfaces and on riveting, and on later service, the rivet head and shank and clinched tail will not engage any bare metal surface. Thus the risk of wear and intermetal reactions or corrosion is avoided by the protection afforded to the stay parts. There is no need to provide a separate low friction washer or bushing under the head of the rivet, or even between relatively movable stay parts so that manufacture and assembly is simpler than previously.

Conveniently, the whole surface of the stay part may be so coated. The use of an entire plastics coating also permits materials such as mild steel to be used for the stay parts instead of the conventionally used extruded aluminium or stainless steel. The conventional materials are selected because of their resistance to corrosion and weathering, but such materials are expensive.

Preferably, the plastics coating is selected from low friction materials such as nylon, neoprene, polyester or epoxy resin, all of which can be applied by the powder coating techniques.

We have found that such coatings of plastics have properties that are such that they have higher resistance to compression than the same plastics materials in extruded or moulded form. In the case of nylon, we have found that the increase in resistance to compressibility can be as much as 20 times. Accordingly, the coating when applied to the stay parts is not likely to deform or spread when the riveting operation is effected and despite the high residual loads applied to the pivot joint by the rivet which engages the plastics coating, there is no likelihood of the plastic spreading or rupturing during service of the stay.

It is also possible to employ different types of rivets, particularly of different metals, without due concern of reaction between two dissimilar metals or other intermetal effects such as cold welding.

Thus in the design of the stays, rivets of various materials and types can be used at will, this being particularly useful where the same design of stay may be used under different conditions and the need to change rivet material might arise.

It will be appreciated that this apparent simple solution overcomes many problems arising in the manufacture of friction stays and their design.

The invention can be applied to a wide range of stay designs having suitable arms, links and mounting plates.

1. A friction stay of the kind defined wherein the surfaces of the stay parts at least adjoining and extending in the pivot joint are coated with a low friction plastics material by a powder coating technique with the coating having a thickness from 0.003" to 0.018".

2. Afriction stay according to claim 1 wherein the entire surface of each stay part is coated with the low friction plastics material.

3. A friction stay according to claim 1 or claim 2 wherein the stay parts are of mild steel.

4. A friction stay according to any one of the preceding claims wherein the stay parts and the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in stays for windows This invention concerns improvements in stays suitable for windows. In particular, stays which are called friction stays and of the kind comprising one or more arms or links and/or mounting plates (such arms, links or plates herein also called stay parts) that are connected together by one or more friction pivot joints which permit restrained pivotal move ment of the stay parts, the stay being adapted and arranged for mounting on a sash and securing to the associated frame so that the sash is supported for frictionally restrained movement on and relative to the frame. Such stays of the kind specified are conventionally used in pairs, one each side of the sash and associated frame. The sash may be hung on the stays for top, bottom or side opening. The frictional restraint to maintain the sash in an adjusted position is provided in the pivot joints by suitable design and manufacture of the pivot joints. The pivot joints are usually provided by rivets which extend through the stay parts with the rivet being clinched in a manner to generate forces which, after clinching, provide the frictional restraint. The operation of the stay when fitted in a window must be smooth and wear of the pivot joint and corrosion must be avoided. It has been proposed previously to fit a self-lubricating bushing or washer under the head of the rivet to provide for the smooth operation, and such bushing, if made of suitable plastics material can assist in corrosion resistance. However, the shank of the rivet is not so protected and there is a risk of metal to metal contact and resultant wear or inter-metallic reactions on weath ering. The use of plastics washers leads to other prob lems in manufacture of such stays for plastics materials suitable for use in such applications have a characteristic of deforming under loads so that the washer or bushing spreads both under the high clinching pressures and the residual pressures in the pivot joint. Thus, it has been found essential to confine the washer or bushing in a recess which extends in the stay part underneath the head of the rivet. Such recess confines the washer or bushing against such deformation. However, the provision of the recess, usually a counter-bore, increases manu facturing costs. Additionally, whilst the recess in the stay part has to be provided, the stay part must be made of material having sufficient thickness and strength for service and the recess effectively weakens the section.This leads to the use of materials which to a large extent are thicker than would be required if the recess were not there. According to this invention, we provide a friction stay of the kind defined wherein the surfaces of the stay parts at least adjoining and extending in the pivot joint are coated with a low friction plastics material by a powder coating technique with the coating having a thickness from 0.003" to 0.018". By providing such a plastics coating the stay parts are provided with low friction surfaces and on riveting, and on later service, the rivet head and shank and clinched tail will not engage any bare metal surface. Thus the risk of wear and intermetal reactions or corrosion is avoided by the protection afforded to the stay parts. There is no need to provide a separate low friction washer or bushing under the head of the rivet, or even between relatively movable stay parts so that manufacture and assembly is simpler than previously. Conveniently, the whole surface of the stay part may be so coated. The use of an entire plastics coating also permits materials such as mild steel to be used for the stay parts instead of the conventionally used extruded aluminium or stainless steel. The conventional materials are selected because of their resistance to corrosion and weathering, but such materials are expensive. Preferably, the plastics coating is selected from low friction materials such as nylon, neoprene, polyester or epoxy resin, all of which can be applied by the powder coating techniques. We have found that such coatings of plastics have properties that are such that they have higher resistance to compression than the same plastics materials in extruded or moulded form. In the case of nylon, we have found that the increase in resistance to compressibility can be as much as 20 times. Accordingly, the coating when applied to the stay parts is not likely to deform or spread when the riveting operation is effected and despite the high residual loads applied to the pivot joint by the rivet which engages the plastics coating, there is no likelihood of the plastic spreading or rupturing during service of the stay. It is also possible to employ different types of rivets, particularly of different metals, without due concern of reaction between two dissimilar metals or other intermetal effects such as cold welding. Thus in the design of the stays, rivets of various materials and types can be used at will, this being particularly useful where the same design of stay may be used under different conditions and the need to change rivet material might arise. It will be appreciated that this apparent simple solution overcomes many problems arising in the manufacture of friction stays and their design. The invention can be applied to a wide range of stay designs having suitable arms, links and mounting plates. CLAIMS

1. A friction stay of the kind defined wherein the surfaces of the stay parts at least adjoining and extending in the pivot joint are coated with a low friction plastics material by a powder coating technique with the coating having a thickness from 0.003" to 0.018".

2. Afriction stay according to claim 1 wherein the entire surface of each stay part is coated with the low friction plastics material.

3. A friction stay according to claim 1 or claim 2 wherein the stay parts are of mild steel.

4. A friction stay according to any one of the preceding claims wherein the stay parts and the rivets are of different metals.

5. A friction stay according to any one of the preceding claims wherein the low friction material is selected from the following group of materials:nylon, neoprene, polyester and epoxy resin.

6. Afriction stay of the kind defined and substantially as hereinbefore described.