GB2118110A

GB2118110A - Spoked wheels

Info

Publication number: GB2118110A
Application number: GB08204199A
Authority: GB
Inventors: Ian Stuart Mclean; Christopher Juden
Original assignee: ZUFFELLATO TIPOGRAFICA; TI Raleigh Industries Ltd
Current assignee: ZUFFELLATO TIPOGRAFICA; TI Raleigh Industries Ltd
Priority date: 1982-02-12
Filing date: 1982-02-12
Publication date: 1983-10-26

Abstract

A wheel has an aluminium or aluminium alloy rim which is connected to a hub by means of a series of tensioned spokes. Each spoke has an enlarged head portion which engages the hub and a threaded end portion which engages a spoke nipple extending through and engaging the periphery of a hole in the rim. The spoke nipples have a head portion which is tightened against the rim in order to adjust the tension of the spokes. The portion of the nipples which engage the rim or the opposed surface of the rim are coated with a solid lubricant, so that by tightening the nipples to a pre-determined torque, an adequate and substantially uniform tension may be applied to each spoke.

Description

SPECIFICATION Spoked wheels This invention relates to spoked wheels and in particular to a method of constructing a spoked wheel with an aluminium or aluminium alloy rim.

The conventional form of spoked wheel comprises a rim and a hub interconnected by a series of tensioned spokes. The spokes are normally secured to the hub by means of an enlarged head portion. Threaded spoke nipples engage the rim of the wheel and extend through holes therein, to engage correspondingly threaded ends of the spokes, so that the nipples may be screwed onto the spokes and tightened against the rim, in order to tension the spokes.

The required tension in the spokes is normally achieved during manufacture in two stages. In the initial assembly stage the nipples are inserted in turn through holes in the rim, and tightened using a screwdriver slot in the head of the nipple. This produces a complete wheel but with only intermediate spoke tensions and with only approximate standards of accuracy of flatness and circularity of the rim. In the second stage, the wheel is fully tensioned and "trued" using either the screwdriver slot, or a spanner on flats provided on the shank of the nipple in order to obtain a firmer grip and to avoid applying a compression force which would increase the load under the head of the nipple. Both stages may be carried out manually, or on automatic or semi-automatic machines. When done by machine, the spoke tension is determined by controlling the torque applied to the nipple.

The above procedure is quite straightforward when the rim of the wheel is made of steel and the nipples are made of brass or steel, normally plated with chromium or similar corrosion resistant layer.

However, with aluminium or aluminium alloy rims, higher spoke tensions are necessary to ensure that the nipples are fully "bedded in" to the relatively softer rim material in order to anticipate such bedding taking place in service, with consequent relaxation of spoke tension. It is also particularly important that the tensions are as uniform as possible to avoid spoke breakage and to maintain the accuracy of the wheel in use. When the truing stage is done by hand, the operator can sense the spoke tension and adjust the tightennng torque to suit. An automatic or semi-automatic machine, however, tightens the nipples to a predetermined torque and it has proved extremely difficult to obtain sufficiently high tensions or satisfactory uniformity of spoke tension using such methods, with aluminium or aluminium alloy rims.

According to one aspect, the present invention provides a method of constructing a wheel in which an aluminium or aluminium alloy rim and a hub are interconnected by means of a series of tensioned spokes, the spokes being tensioned by means of screw threaded spoke nipples, each of said spoke nipples having a head portion which engages the rim and a shank portion which extends through a hole in the rim to engage a correspondingly threaded end portion of a spoke, so that the spoke nipple can be screwed onto the spoke and its head portion tightened against the rim in order to adjust the tension of the spoke, the portions of the spoke nipples which engage the rim or the portions of the rim engaged thereby, having a coating of solid lubricant applied thereto, and each spoke nipple being tightened to a predetermined torque, so as to apply an adequate and substantially uniform tension to all the spokes.

The solid lubricant may be applied to the spoke nipples or to the rim by any convenient method.

Where the coating is applied to the spoke nipples, it will normally be convenient to coat the whole of the nipple. This coating may also act as a corrosion inhibiting coating thus avoiding the need to plate the nipples, as is done at present. Where the coating is applied to the rim, it may be applied at discreet zones around each spoke hole or more conveniently as a continuous band around the rim and of sufficient width to embrace all the spoke holes. Where the coating is applied to the rim, conventional plated spoke nipples may be used.

According to one embodiment of the invention, brass spoke nipples were coated with a PTFE/resin formulation which is commercially available as FASTNACOTE from Acheson Colloids Company.

This formulation was dissolved in a solvent and applied to the nipples by a spray barrelling technique, followed by a further barrelling until dry. The coated nipples were then stove dried at 2000C, in order to cure the resin.

In tests, it was found that with an aluminium rim, the nipples coated in the manner described above required a spannering torque of 0.23Nm to develop a spoke tension of 445N and 0.39Nm to develop a spoke tension of 890N. This compares with spannering torques of 0.40Nm and 0.86Nm (respectively) for plated nipples against steel rims and 0.58Nm and 1.59Nm (respectively) for plated nipples against aluminium rims.

The relatively low torque values required to develop the higher spoke tensions (i.e. around 890N) required with aluminium or aluminium alloy rims, enables conventional wheel building equipment to be used, without any difficulties.

Furthermore it was found that the torque figures obtained for the coated nipples against aluminium rims were extremely consistent, so that wheels built using these nipples have significantly improved uniformity of spoke tension.

Various modifications may be made without departing from the invention. For example, while this invention enables spoked aluminium rimmed wheels to be built to a high standard on conventional wheel building equipment, it may also be used with hand assembly techniques. The solid lubricant compositions used in accordance with the present invention mayy if desired, be coloured for decoration or identification purposes.

1. A method of constructing a wheel in which an aluminium or aluminium alloy rim and a hub

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Spoked wheels This invention relates to spoked wheels and in particular to a method of constructing a spoked wheel with an aluminium or aluminium alloy rim. The conventional form of spoked wheel comprises a rim and a hub interconnected by a series of tensioned spokes. The spokes are normally secured to the hub by means of an enlarged head portion. Threaded spoke nipples engage the rim of the wheel and extend through holes therein, to engage correspondingly threaded ends of the spokes, so that the nipples may be screwed onto the spokes and tightened against the rim, in order to tension the spokes. The required tension in the spokes is normally achieved during manufacture in two stages. In the initial assembly stage the nipples are inserted in turn through holes in the rim, and tightened using a screwdriver slot in the head of the nipple. This produces a complete wheel but with only intermediate spoke tensions and with only approximate standards of accuracy of flatness and circularity of the rim. In the second stage, the wheel is fully tensioned and "trued" using either the screwdriver slot, or a spanner on flats provided on the shank of the nipple in order to obtain a firmer grip and to avoid applying a compression force which would increase the load under the head of the nipple. Both stages may be carried out manually, or on automatic or semi-automatic machines. When done by machine, the spoke tension is determined by controlling the torque applied to the nipple. The above procedure is quite straightforward when the rim of the wheel is made of steel and the nipples are made of brass or steel, normally plated with chromium or similar corrosion resistant layer. However, with aluminium or aluminium alloy rims, higher spoke tensions are necessary to ensure that the nipples are fully "bedded in" to the relatively softer rim material in order to anticipate such bedding taking place in service, with consequent relaxation of spoke tension. It is also particularly important that the tensions are as uniform as possible to avoid spoke breakage and to maintain the accuracy of the wheel in use. When the truing stage is done by hand, the operator can sense the spoke tension and adjust the tightennng torque to suit. An automatic or semi-automatic machine, however, tightens the nipples to a predetermined torque and it has proved extremely difficult to obtain sufficiently high tensions or satisfactory uniformity of spoke tension using such methods, with aluminium or aluminium alloy rims. According to one aspect, the present invention provides a method of constructing a wheel in which an aluminium or aluminium alloy rim and a hub are interconnected by means of a series of tensioned spokes, the spokes being tensioned by means of screw threaded spoke nipples, each of said spoke nipples having a head portion which engages the rim and a shank portion which extends through a hole in the rim to engage a correspondingly threaded end portion of a spoke, so that the spoke nipple can be screwed onto the spoke and its head portion tightened against the rim in order to adjust the tension of the spoke, the portions of the spoke nipples which engage the rim or the portions of the rim engaged thereby, having a coating of solid lubricant applied thereto, and each spoke nipple being tightened to a predetermined torque, so as to apply an adequate and substantially uniform tension to all the spokes. The solid lubricant may be applied to the spoke nipples or to the rim by any convenient method. Where the coating is applied to the spoke nipples, it will normally be convenient to coat the whole of the nipple. This coating may also act as a corrosion inhibiting coating thus avoiding the need to plate the nipples, as is done at present. Where the coating is applied to the rim, it may be applied at discreet zones around each spoke hole or more conveniently as a continuous band around the rim and of sufficient width to embrace all the spoke holes. Where the coating is applied to the rim, conventional plated spoke nipples may be used. According to one embodiment of the invention, brass spoke nipples were coated with a PTFE/resin formulation which is commercially available as FASTNACOTE from Acheson Colloids Company. This formulation was dissolved in a solvent and applied to the nipples by a spray barrelling technique, followed by a further barrelling until dry. The coated nipples were then stove dried at 2000C, in order to cure the resin. In tests, it was found that with an aluminium rim, the nipples coated in the manner described above required a spannering torque of 0.23Nm to develop a spoke tension of 445N and 0.39Nm to develop a spoke tension of 890N. This compares with spannering torques of 0.40Nm and 0.86Nm (respectively) for plated nipples against steel rims and 0.58Nm and 1.59Nm (respectively) for plated nipples against aluminium rims. The relatively low torque values required to develop the higher spoke tensions (i.e. around 890N) required with aluminium or aluminium alloy rims, enables conventional wheel building equipment to be used, without any difficulties. Furthermore it was found that the torque figures obtained for the coated nipples against aluminium rims were extremely consistent, so that wheels built using these nipples have significantly improved uniformity of spoke tension. Various modifications may be made without departing from the invention. For example, while this invention enables spoked aluminium rimmed wheels to be built to a high standard on conventional wheel building equipment, it may also be used with hand assembly techniques. The solid lubricant compositions used in accordance with the present invention mayy if desired, be coloured for decoration or identification purposes. CLAIMS

1. A method of constructing a wheel in which an aluminium or aluminium alloy rim and a hub are interconnected by means of a series of tensioned spokes, the spokes being tensioned by means of screw threaded spoke nipples, each of said spoke nipples having a head portion which engages the rim and a shank portion which extends through a hole in the rim to engage a correspondingly threaded end portion of a spoke, so that the spoke nipple can be screwed onto the spoke and its head portion tightened against the rim in order to adjust the tension of the spoke, the portions of the nipples which engage the rim or the portions of the rim engaged thereby, having a coating of solid lubricant applied thereto, and each spoke nipple being tightened to a predetermined torque, so as to apply an adequate and substantially uniform tension to all the spokes.

2. A method according to Claim 1 in which the coating of solid lubricant is applied tithe whole of the spoke nipple and acts as a corrosion inhibiting coating.

3. A method according to Claim 1 in which the coating is applied to the rim, to discreet zones about each spoke hole.

4. A method according to Claim 1 in which the coating is applied to the rim, as a continuous band around the rim and of sufficient width to embrace all the spoke holes.

5. A method according to any one of the preceeding claims in which the coating comprises a formulation of PTFE and a resin.

6. A method according to Claim 5 in which the PTFE/resin formulation is applied as a solution which is subsequently dried and stoved, in order to cure the resin.

7. A method of constructing a wheel in which an aluminium or aluminium alloy rim and a hub are interconnected by a series of tensioned spokes, substantially as described herein.

8. A wheel in which an aluminium or aluminium alloy rim and hub are interconnected by a series of tensioned spokes, made in accordance with any of the preceding claims.