Field of the Invention
This invention relates to leaf springs made of composite, fibre reinforced synthetic resin, material.
Composite leaf springs may be used, for example, in motor vehicles. By such use, considerable savings in weight can be achieved as compared with the use of conventional steel leaf springs. A composite spring may comprise glass and/or carbon fibres set within a matrix of a cured resin, for example, an epoxy resin. By the selection of suitable fibres and, in particular, the orientation of such fibres within the spring with some fibres oriented substantially longitudinally of the spring and some fibres in other orientations, a spring can be manufactured which is considerably lighter than a steel leaf spring having the same springing properties.
However, leaf springs of composite material can be relatively expensive to produce when compared with steel springs. One area of significance in this respect is at the ends of the spring where it is required to be attached to a vehicle. In the case of a steel spring, the ends of the spring can simply be scrolled to provide a transverse aperture suitable for receiving a bush and pin for mounting the spring, whereas this cannot easily be done in the case of a composite spring. It has been proposed that a composite spring can be provided with an end fitting in which the material of the spring is surrounded and reinforced by a pair of metal members which are clamped together and which secure an eye to the spring for receiving a fixing bolt or pin, but this is relatively complex and expensive.