Safer nuts to the industry
Page 19
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By Tim Blakemore
THE INSTITUTE of Road Transport Engineers' campaign for research into the wheel fixing failures problem (CM, January 19) has prompted several companies to come forward with possible solutions.
RotaBolt is manufactured by a West Midlands company of the same name. This device won the 1983 Design Council Award for Technical Achievement and is currently being used by Norde on its rubber suspension units.
The RotaBolt provides an accurate yet simple means of checking that a bolt, or nut on a stud, is at the correct torque. The manufacturer is confident that RotaBolt will provide a more accurate check than a torque wrench, to within a tolerance of plus or minus five per cent of the fixing's design load.
When a knurled load indicator disc which caps a gauge pin at the exposed end of the RotaBolt can no longer be turned, then the stud or bolt is at the correct pre-set load. A close fitting cap protects the knurled disc and gauge pin.
RotaBolt has no doubt that its device will continue to work accurately in the harsh environment to which commercial vehicle wheel studs are exposed. They are currently in use on North Sea oil rigs.
Forest Fasteners' solution to the wheel fixing failure problem is a two-piece wheel nut, comprising a hardened and tempered nut body with a captive low-tensile washer.
The nut's radius is smaller than that of the washer and provides a mechanical locking effect. Forest Fasteners is at Pontypridd, Mid Glamorgan, South Wales.
Permabond Adhesives of Eastleigh, Hampshire, offers a liquid adhesive to keep wheel nuts in place. Wheeltite is supplied in 200m1 tubes each of which the manufacturer reckons will be enough to treat 150 nuts, at a cost of about 9p per nut.
Permabond says that its adhesives will not prevent wheel removal and refitting using normal tools.