FR2586378A1 - Assembly forming a very lightweight wheel spoke consisting of composite materials and metal elements - Google Patents

Abstract

Assembly forming a very lightweight wheel spoke consisting of a rod 1, which is made from glass fibres, synthetic carbon fibres, aramid fibres or the like, hybrid fibres thereof, combined with polymerised resins, and which is crimped or adhesively bonded in metal end elements 2, 3 and 4, making it possible to fasten securely under tension the wheel rim of a wheel to its hub.

Description

SET COMPRISING A VERY LIGHT RADIUS
OF WHEEL CONSISTING OF COMPOSITE MATERIALS AND METALLIC ELEMENTS
It is clear that the lighter a bicycle, the better the performance of the cyclist. To lighten the whole of the bicycle, it is necessary to lighten the constituent elements but it is not necessary to make the whole fragile.

 Thus, we can successively lighten the frame, handlebars, wheel.

 The lightening of the spoked wheels of a bicycle presents significant advantages for the user not only for a reason of less weight to be driven, less inertia of the wheel which also allows better acceleration, but also for a reason of maintenance of the cyclist's balance: the lighter the front wheel, the better the balance.

 To lighten a wheel, you can lighten the spokes that connect the rim to the hub. A good-quality cycle wheel spoke must not only withstand high tensile forces, but it must also be as thin as possible so as not to offer wind resistance.

 We finally know that a spoke is fixed to the rim of the wheel by a tensioning nut while the end fixed to the wheel hub is generally bent in the shape of a hook terminated by a hammer head to come and hang in a plate secured to the hub rotating around the axis of the wheel.

 To lighten the wheel, we could use very light synthetic fibers. The fibers of aromatic polyamides, aramides, are particularly resistant to tensile forces. However, they are less rigid even when combined with polymerized resins than the carbon fibers themselves associated with resins. A hybrid composite of aramid fibers and carbon fibers would offer good mechanical characteristics for making spokes.

These fibers are only mentioned by way of example, since other glass or synthetic fibers also have interesting qualities.

 But the synthetic fibers associated with resins can hardly be bent, sometimes hot but then they can lose some of their mechanical characteristics and when they are threaded by bar turning the fibers of the threads are cut and the thread offers less resistance to traction.

 The devices according to the invention remedy these drawbacks by permitting the use of synthetic fibers to lighten the spokes by crimping or gluing at the ends of a fiber rod, which can be obtained by the pultrusion process, metal tubes which will either be threaded or bent to allow the junctions with the rim and with the hub.

 To clearly understand the invention, there will be briefly described below non-limiting exemplary embodiments thereof with reference to the appended schematic drawings in which: FIG. 1 is a section along the axis of a radius with a "hammer head" "not bent.

 Figure 2 is a section through a rim (6) to which the spoke (1) is fixed by the tensioning nut 4. Figure 3 is a section through a bent end of a hammer head spoke. Figure 4 is a section along the axis of a radius in which the tensor nut is replaced by a tensioning screw (5) located near the hub. This arrangement makes it possible to lighten the radius at the level of the attachment to the rim, which has the effect of reducing the inertia of the latter thus facilitating acceleration.

 The device shown in Figure 1 consists of a rod (1) of synthetic fibers associated with resins. This rod (1) at one of these ends is crimped inside a metal part (2) in the form of a hollow rivet carrying a shaped head which will be housed in the hub. The other end is crimped inside a threaded sleeve on its periphery. This sleeve (3) will be introduced into the tensioning nut (4), the bearing face (7) of which rests on the internal strip of the rim. Said rim (6) is shown in section in FIG. 2. The radius (1) crimped inside the sleeve (3) makes an angle d with the axis of the rim. This angle is a function of the radius of the rim and the width of the wheel axis. The radius (1) is tensioned T by the tensioning nut (4) whose bearing face (7) rests on the inner face of the rim (6) and exerts on it a pressure P depending on the tension T.

 Figure 3 shows a variant of the device of Figure 1 in which the hammer head rivet (2) is bent in the form of a hook.

This arrangement, commonly adopted, shows how the traction T is exerted on the plate (8) of the wheel hub whose axis makes an angle with the axis of the radius.

 FIG. 4 shows another device for tightening the spoke in which the spoke (1) is crimped into a head, a metallic rivet (4), which will be housed in the rim in place of the tensing nut t4) of FIG. 2. The other end of the spoke (1) is crimped into a threaded metal sleeve (3) secured to the hook, hammer head, (2) by a turnbuckle (5) which will be screwed to carry out the tensioning T of the spoke, the rim and hub.

Claims (2)

 1) An assembly comprising a very light wheel spoke, characterized in that it consists of a rod (1) made of synthetic fibers associated with resins, one end of which is crimped or glued inside a metal part (2) in the form of a hollow rivet carrying a shaped head accommodating in the hub and the other end of which is crimped or glued inside a sleeve (3j threaded on its periphery, said sleeve (3 ) being introduced into the tensioning nut (4) whose bearing face (7) rests on the inner strip of the rim.  2) set of composite and metallic elements according to claim 1 characterized in that the radius t1) is equipped at one of its ends with a bent and threaded rivet (2) introduced into a turnbuckle (5) and whose l the other end is crimped on the one hand inside a rivet (4) housed in the rim and on the other hand in a threaded metal sleeve (3) and introduced into the tensioning turnbuckle (5).