FASTENING CONSTRUCTION FOR DETACHABLY FASTENING AN EXTRA WHEEL TO A ROAD WHEEL OF A TRACTOR OR LIKE VEHICLE

Abstract: By detachably fastening an extra wheel to a road wheel of a tractor, the weight of the tractor is distributed over a larger area, so that the wheels of the tractor will penetrate less deeply into soft ground. The fastening construction comprises a central nut (3), a plurality of spokes (5) welded to the nut, wherein to at least some of the spokes (5) an approximately L-shaped lever (6) is pivotally fastened; the outer end of said levers (6) is provided with a boss (15), while the inner end cooperates with a threaded spindle (7) screwed through the nut (3); each boss (15) when in the fastening position engages in a receiving member (16) welded to the rim (1) of the road wheel. To make the road wheel suitable for all numbers and mutual distributions of the L-shaped levers and to avoid positioning problems, the receiving member (16) consists for this purpose of a ring extending around the entire periphery of the road wheel and having a recess (19) to receive the bosses (15).

Description: The invention relates to a fastening construction for detachably fastening an extra wheel to a road wheel of a tractor or like vehicle, comprising a threaded spindle, a plurality of spokes connected to the rim of the extra wheel and maintaining said threaded spindle in a substantially central axial position with respect to the extra wheel, a nut screwed on said threaded spindle, a number of approximately L-shaped levers each pivotally connected to a spoke, said levers having at their outer ends a boss and cooperating at their inner ends with the assembly of nut and threaded spindle sothat by rotating one of them the levers are pivoted, and an angular receiving member connected to the road wheel, each boss, when in the fastening position, engaging in said receiving member. Such a fastening construction is disclosed in EP-A-0049 420. The extra wheel may be a so-called cage wheel or a so-called double pneumatic tired wheel consisting in the usual manner of a rim and a pneumatic tire. Both types of extra wheels provide the advantage that the weight of the tractor is distributed over a larger area, sothat the wheels of the tractor will penetrate less deeply into soft ground. In the known construction the angular receiving member comprises a considerable number (for instance 32) of segments as well as a similar number of radial ribs. Each segment has a conical bore tapering radially outwards. Each bore is intended for taking up one boss of a L-shaped lever. This construction is not suitable for all numbers and mutual distributions of the L-shaped levers. An other disadvantage is that the receiving member is a complicated expensive member. The invention seeks to provide a fastening construction of the type first defined above avoiding the above disadvantages and avoiding positioning problems. According to the invention the receiving member is a simple ring directly welded to the rim of the road wheel and having one single recess facing the axis of the road wheel and extending continuously along the entire inner circumference of the ring. The recess is preferably trapezoidal in shape. The invention also relates to a road wheel clearly intended for the aforesaid fastening construction, for a tractor or like vehicle, which road wheel is provided with a ring extending around its periphery and having a recess. The invention will now be explained more fully with the aid of the drawings, in which one example of embodiment is illustrated. Figure 1 is an axial cross-section of the rims of a tractor wheel and of an extra wheel fastened to it, in which arrangement the fastening construction according to the invention is utilized. Figure 2 is a side view of the extra wheel. Figure 3 is a section on a larger scale of a part of the road wheel rim. The left-hand side of Figure 1 shows the rim 1 of a wheel of an agricultural tractor, while the right-hand side shows the rim 2 of an extra wheel (a so-called double pneumatic tyred wheel), which is fastened to the tractor wheel rim by a fastening construction which will be described more fully. The fastening construction comprises a central nut 3 provided with three star wings 4 forming an integral unit, three spokes 5, three substantially L-shaped levers 6, and a threaded pindle 7 screwed through the nut. Each of the spokes 5 consists of two steel strips 8, 9, which at their inner ends are welded to a wing 4 of the nut 3 and at their outer ends are welded to an attached member 10. The levers 6 are pivotally mounted on a bolt or pin 11 which passes through openings in a set of spoke strips 8, 9 and, in the example illustrated, is fastened by a nut 12. The inner end of each lever 6 is provided with a U-section 13 engaging over a ring 14 joined to the spindle 7. At the outer end of each lever 6 is attached a projecting boss 15, which in the fastened position of the wheel 2 shown in Figure 1 engages in a receiving member 16 joined to the rim 1. According to the invention the receiving member 16 is in the form of a steel ring which is welded at 17 and 18 to the rim 1 and in which a trapezoidal recess 19 is formed. The leg of the trapezium facing the extra wheel is somewnat shorter than the other leg, so that the boss can be more easily moved into and out of the recess. The construction illustrated has the advantage that the ring 16 is suitable for all star arrangements of the levers 6 and that positioning problems no longer occur. Various modifications are possible within the scope of the invention as defined in the appended claims.

Claims: Fastening construction for detachably fastening an extra wheel to a road wheel of a tractor or like vehicle, comprising a threaded spindle (7), a plurality of spokes (5) connected to the rim of the extra wheel (2) and maintaining said threaded spindle (7) in a substantially central axial position with respect to the extra wheel, a nut (3) screwed on said threaded spindle, a number of approximately L-shaped levers (6) each pivotally connected to a spoke (5), said levers having at their outer ends a boss (15) and cooperating at their inner ends with the assembly of nut and threaded spindle sothat by rotating one of them the levers are pivoted, and an angular receiving member (17) connected to the road wheel, each boss (15), when in the fastening position, engaging in said receiving member, characterized in that said receiving (16) is a simple ring directly welded to the rim of the road wheel and having one single recess (19) facing the axis of the road wheel and extending continuously along the entire inner circumference of the ring (16). Fastening construction according to claim 1, characterized in, that the recess (19) is substantially trapezoidal in shape. Road wheel clearly intended for the construction according to claim 1 or 2, said wheel having an angular receiving member (16), characterized in, that the receiving member is a simple ring directly welded to the rim of the road wheel and having one single recess (19) facing the axis of the road wheel and extending continuously along the entire inner circumference of the ring (16).

Inventors: MOL, PIETER KRIJN
Applicants: MOL, PIETER KRIJN
Application year: 1987
Main classification: B60B11
IPC codes: B60B11