Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60B—VEHICLE WHEELS; CASTORS; AXLES FOR WHEELS OR CASTORS; INCREASING WHEEL ADHESION
  • B60B23/00—Attaching rim to wheel body
  • B60B23/12—Attaching rim to wheel body by devices arranged to permit variation of axial position of rim relative to wheel body for track width adjustment

Definitions

• This invention relates to power-adjustable-variable- track (PAVT) wheels. These wheels find their main use on tractors whereby the track of the tractor wheels can be varied using the power of the tractor.
• PAVT power-adjustable-variable- track
• PAVT wheels each comprising a separate disc and rim.
• the rim has secured to the inner periphery thereof a plurality of part-helical rails arranged in circumferentially-spaced relation.
• the disc carries brackets which engage the rails whereby, upon relative rotation between the disc and the rim, they are also moved relative to one another in directions parallel to the rotary axis of the wheel as the brackets move along the rails.
• PAVT wheels are hereinafter referred to as being "of the type described”.
• PAVT wheels of the type described the locking means which are provided to hold the brackets and rails in a desired position rely on friction between a movable locking member on each bracket and the rail with which the bracket engages. Because of the tolerances between the various parts of the wheel it is often only the final locking member to be tightened into frictional engagement with the rail which actually serves any useful purpose and with high-powered tractors working at or near their maximum capacity there has been slippage of the disc relative to the rim in such wheels.
• each bracket carries a radially disposed lug bolt which constitutes the locking member and which has a U-shaped outer end portion which engages a rail.
• the disc and rim are held in the desired position by frictional engagement between the rails and the outer end portions of the lug bolts.
• An object of the invention is to provide a PAVT wheel which overcomes these problems, is easy and quick to adjust and which has good lateral, i.e. in directions parallel to the rotary axis of the wheel, and radial truth.
• each bracket is bifurcated and engages a rail between the limbs of its bifurcation, the bracket being provided with at least one bolt hole; and wherein each rail is provided with a plurality of bolt holes, the wheel being adjusted by bringing the bolt holes in the brackets into alignment with bolt holes in the rails, inserting bolts through the aligned holes and securing the bolts in position.
• Such a wheel has a number of advantages over prior art wheels such as exemplified by said U.S. Patent Serial No. 3,048,443.
• each bracket Preferably there are two bolt holes in each bracket, preferably, also, the bolt hole or bolt holes is or are in one only of the limbs of the bifurcation, the other limb serving only to retain the bracket on the rail.
• each bracket is bolted to the disc and the disc and the bracket each have two faces at right angles which are in mutual engagement.
• the disc is in the shape of a square with its corners cut off, thus to produce an irregular octagon, having longer sides and shorter sides alternately arranged around the periphery of the octagon, the brackets being secured to each shorter side by a pair of bolts.
• the edge of each shorter side may provide one of said faces.
• Figure 1 is a front elevation of a wheel embodying the invention
• Figure 2 is a part-section on the line 2-2 of Figure 1;
• Figure 3 is a detail elevation showing how one of the brackets engages a rail
• Figure 4 is a view of the parts in Figure 3 in the direction of the arrow 4 in Figure 3;
• Figure 5 is a perspective view of one of the brackets.
• the PAVT wheel there shown comprises a disc 10 and a rim 11.
• the disc is of uniform thickness and in elevation has the shape of an irregular octagon formed by taking a square and cutting off the corners so that the disc has four longer sides 12 and four shorter sides 13, the sides 12 and 13 being arranged alternately around the periphery of the disc.
• the sides 13 are arcuate.
• the disc has a central hole 14 to receive a vehicle hub and a ring of bolt holes 15 whereby it can be connected to the hub.
• the disc has a central or nave portion 11 , an inner portion 11 b substantially perpendicular to the rotary axis of the wheel, a conical portion 11 and an outer portion 11 d which is also perpendicular to said rotary axis.
• bracket 17 To each shorter side 13 of the disc is bolted a bracket, there being four brackets 16, 17, 18 and 19. These brackets are identical. Referring now to Figures 2 to 5 the bracket 17 will be described by way of example.
• the bracket has a flange 20 which is bolted to the disc 10 by two bolt, nut and washer assemblies 21 passing through aligned bolt holes in the bracket and the disc; the holes in the bracket are shown at 21 in Figure 5.
• the flange 20 fits closely alongside the disc 10 and lateral truth is thus ensured.
• the edge of the shorter side 13 of the disc closely engages a shoulder 22 provided on the bracket at the side of the flange, radial truth of the bracket relative to the disc is thus ensured.
• Each bracket is bifurcated and has, as is most clearly shown in Figure 5, a shorter limb 23 and a longer limb 24, the limbs being separated by a channel 25.
• the inwardly facing surface 23 a_ of the limb 23 is parallel to surfaces 24 a. on the limb 24.
• the longitudinal axis of the channel 25 is inclined to the flange 20 as clearly shown in Figures 2 and 4.
• Each rail on the rim which will now be described, fits in the channel 25 between the limbs of one of the brackets.
• each of the rails is in the same plane which is perpendicular to the rotary axis of the wheel and the other ends of the rails are in a different plane perpendicular to said axis.
• a block such as 32 is welded to each end of each rail to act as a stop to prevent the bracket leaving the rail.
• the shorter limb 23 of each bracket lies to one side of the rail whereas the longer limb 24 lies to the other side of the rail, the latter being received in the channel 25.
• Each of the rails for example the rail 27 in the Figures 1, 2 and 3, is provided with a plurality of spaced holes indicated at 33 to 39 respectively.
• the spacing between each adjacent pair of the holes 33 to 39 is the same as the spacing between the holes 40 in the limb 24.
• each of the brackets 16 to 19 can have the holes therein aligned with an adjacent pair of holes in whichever of the rails 26 to 29 it engages and the wheel and disc can be secured in position by inserting through the aligned holes bolt, nut and washer assemblies such as 41. When these are tightened up the disc is secured to the rim via the rails and any clearance between the bracket limbs 24 and the rails is taken up thus ensuring that the rim is laterally true with respect to the disc. Radial truth is ensured as described above by the disc sides 13 engaging the shoulders 22.
• stops 42 are arranged in appropriate positions on each of the rails 27 and 29 and held there by nut and bolt assemblies 43. Two stops are shown, one on each of the rails 27 and 29, but any number of stops from one to four may be used. Assuming that the rim with the tyre thereon is resting on the ground, the disc can be turned by engaging the tractor in gear, and the disc will turn relative to the rim, in the case shown, in a clockwise direction, until the brackets 17 and 19 engage the stops 42.
• brackets 13 and 18 will be bolted to the rails 26 and 28 respectively. Each rail will be clamped against the surfaces 24 a on a bracket and thus lateral truth will be obtained. Each wheel will be adjusted separately.
• the invention thus provides a PAVT wheel of the type described in which there is positive locking between the rim and the disc and in which lateral and radial truth is easily and accurately obtained.
• the locking does not involve any radially applied force which can distort the rim and which often occurs in prior art PAVT wheels and as described above. Since there is no relative radial movement between the brackets and the rails, adjustment is very smooth and each adjustment e.g. position or track setting, can be readily obtained.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Machines For Laying And Maintaining Railways (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10590995

Family Applications (1)

Country Status (3)

Family Cites Families (6)

• 1986
  • 1986-05-15 BR BR8607357A patent/BR8607357A/pt unknown
  • 1986-05-15 EP EP19860903458 patent/EP0307392A1/de not_active Ceased
  • 1986-05-15 WO PCT/GB1986/000269 patent/WO1987006890A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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