GB2130978A

GB2130978A - Tractor wheels

Info

Publication number: GB2130978A
Application number: GB8230099A
Authority: GB
Inventors: David Gee-Clough
Original assignee: CAB CRAFT Ltd
Current assignee: CAB CRAFT Ltd
Priority date: 1982-10-21
Filing date: 1982-10-21
Publication date: 1984-06-13
Also published as: GB2130978B

Abstract

A tractor wheel, intended to replace an existing tyred wheel and minimise soil compaction, comprises a pair of circular side frames (2) connected by a series of axial bars (6) of V-section, Each bar has a longer limb (7) which is effective for forward rotation of the wheel, extending at an angle of 25 DEG -35 DEG , preferably 30 DEG , to the local radius of the wheel, and a shorter limb (8) which is effective for reverse rotation of the wheel, extending at an angle of 5 DEG -15 DEG , preferably 10 DEG , to the local radius. <IMAGE>

Description

SPECIFICATION Tractor wheels This invention relates to wheels for tractors.

So-called 'cage wheels' are known which generally comprise a series of tubular groundengaging bars which interconnect a pair of circular side-frames to form a cylindrical cage, the bars extending obliquely to a tangent to the cylinder.

Cage wheels are normally attached to an existing tyred tractor wheel to spread the load in difficult soil conditions.

In tests it has been found that the use of such a cage wheel does relatively little to decrease the intensity of soil compaction below the rear wheel of a tractor as compared with a conventional tractor wheel on its own. The use of dual rubber tyres and very wide section tyres have been studied and whilst these may be more effective in reducing the intensity of compaction a considerably higher cost would be incurred as compared with using a cage wheel.

The present invention results from experiments on wheels comprising a framework of metal bars and in which ground engaging bars other than tubular bars have been employed. Such a wheel is intended to replace an existing tyred wheel rather than be used in conjunction with such a wheel.

Non-tubular ground engaging bars have previously been proposed in cage wheels to meet special requirements. For example, Specification No. G.B. 762,852 illustrates a cage wheel for use with a conventional wheel in rice fields in which the ground engaging bars are of angle section with one limb of the section extending radially of the wheel, to act as a paddle, and the other limb extending circumferentially. Specification No. G.B.

783,429 illustrates a similar cage for use in rice fields, again with angle-section bars but in this case the two limbs of a bar extend at 450 to the radius of the wheel, with the concave side of the bar facing radially outwards. Such cage wheels were not intended for use on normal soils.

According to one aspect of the invention a tractor wheel comprises two axially spaced apart circular frames rigidly connected by a series of circumferentially spaced ground engaging bars, the bars each comprising an elongate flat plate lying in a plane inclined to a radius to the wheel at an angle in the range substantially 250 to substantially 350.

Preferably said angle is substantially 300, at which angle it is found that a substantial reduction in soil compaction is produced.

Preferably the bars extend substantially axially of the wheel.

Such a wheel is used with the normal direction of rotation such that on contact with the ground the forward edge of the plate is radially outward of the rearward edge of the plate, to provide a wedging engagement with the ground.

According to a second aspect of the invention a tractor wheel comprises two axially spaced apart circular frames rigidly connected by a series of circumferentially spaced ground engaging bars, the bars each being of substantially V-section with the point of the V directed radially outwardly of the wheel.

With this arrangement one limb of the V provides a wedging engagement with the ground for forward rotation of the wheel, and the other limb provides a wedging engagment for reverse rotation.

Said other limb is conveniently made of shorter length than said one limb.

Preferably said one limb is directed at an angle in the range substantially 250 to substantially 350 to a radius of the wheel, and most preferably said angle is substantially 300.

The angle between said other limb and a radius of the wheel is preferably in the range substantially 50 to substantially 1 50, and is most preferably substantially 100.

A tractor wheel in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side elevation of the wheel: Figure 2 is a section on the line 2-2 of Figure 1;and Figure 3 is an enlargement of the portion A of Figure 1.

The wheel comprises a pair of circular side frames 1, 2 rolled from flat section steel with the ends butt welded. Frame 1 is connected to a mounting disc 3 by four inclined box-section bars 4 welded at their opposite ends, and frame 2 is similarly connected to disc 3 by four inclined boxsection bars 5 positioned angularly intermediate bars 4. Disc 3 is provided with a series of holes 3' for attachment directly to a tractor hub by means of the studs which would normally be employed to secure a tyred tractor wheel to the hub.

A series of sixteen circumferentially equally spaced V-section bars 6 extend axially between side frames 1, 2 and have their opposite ends welded thereto. The bars are fabricated from 4 mm steel by folding to provide a 100 mm long limb 7 and a 90 mm long limb 8. The longer limb 7 extends at an angle of 300 to the local wheel radius, and the shorter limb 8 at an angle of 100, with the point 9 of the V being directed radially outwards and being flush with the radially outer edges of frames 1, 2.

The direction of forward rotation of the wheel is indicated by the arrow B in Figure 1.

1. A tractor wheel comprising two axially spaced apart circular frames rigidly connected by a series of circumferentially spaced ground engaging bars, the bars each comprising an elongate flat plate lying in a plane inclined to a radius to the wheel at an angle in the range substantially 250 to substantially 350.

2. A tractor wheel as claimed in claim 1 in which said angle is substantially 300.

3. A tractor wheel as claimed in claim 1 or claim 2 in which the bars extend substantially axially of the wheel.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Tractor wheels This invention relates to wheels for tractors. So-called 'cage wheels' are known which generally comprise a series of tubular groundengaging bars which interconnect a pair of circular side-frames to form a cylindrical cage, the bars extending obliquely to a tangent to the cylinder. Cage wheels are normally attached to an existing tyred tractor wheel to spread the load in difficult soil conditions. In tests it has been found that the use of such a cage wheel does relatively little to decrease the intensity of soil compaction below the rear wheel of a tractor as compared with a conventional tractor wheel on its own. The use of dual rubber tyres and very wide section tyres have been studied and whilst these may be more effective in reducing the intensity of compaction a considerably higher cost would be incurred as compared with using a cage wheel. The present invention results from experiments on wheels comprising a framework of metal bars and in which ground engaging bars other than tubular bars have been employed. Such a wheel is intended to replace an existing tyred wheel rather than be used in conjunction with such a wheel. Non-tubular ground engaging bars have previously been proposed in cage wheels to meet special requirements. For example, Specification No. G.B. 762,852 illustrates a cage wheel for use with a conventional wheel in rice fields in which the ground engaging bars are of angle section with one limb of the section extending radially of the wheel, to act as a paddle, and the other limb extending circumferentially. Specification No. G.B. 783,429 illustrates a similar cage for use in rice fields, again with angle-section bars but in this case the two limbs of a bar extend at 450 to the radius of the wheel, with the concave side of the bar facing radially outwards. Such cage wheels were not intended for use on normal soils. According to one aspect of the invention a tractor wheel comprises two axially spaced apart circular frames rigidly connected by a series of circumferentially spaced ground engaging bars, the bars each comprising an elongate flat plate lying in a plane inclined to a radius to the wheel at an angle in the range substantially 250 to substantially 350. Preferably said angle is substantially 300, at which angle it is found that a substantial reduction in soil compaction is produced. Preferably the bars extend substantially axially of the wheel. Such a wheel is used with the normal direction of rotation such that on contact with the ground the forward edge of the plate is radially outward of the rearward edge of the plate, to provide a wedging engagement with the ground. According to a second aspect of the invention a tractor wheel comprises two axially spaced apart circular frames rigidly connected by a series of circumferentially spaced ground engaging bars, the bars each being of substantially V-section with the point of the V directed radially outwardly of the wheel. With this arrangement one limb of the V provides a wedging engagement with the ground for forward rotation of the wheel, and the other limb provides a wedging engagment for reverse rotation. Said other limb is conveniently made of shorter length than said one limb. Preferably said one limb is directed at an angle in the range substantially 250 to substantially 350 to a radius of the wheel, and most preferably said angle is substantially 300. The angle between said other limb and a radius of the wheel is preferably in the range substantially 50 to substantially 1 50, and is most preferably substantially 100. A tractor wheel in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side elevation of the wheel: Figure 2 is a section on the line 2-2 of Figure 1;and Figure 3 is an enlargement of the portion A of Figure 1. The wheel comprises a pair of circular side frames 1, 2 rolled from flat section steel with the ends butt welded. Frame 1 is connected to a mounting disc 3 by four inclined box-section bars 4 welded at their opposite ends, and frame 2 is similarly connected to disc 3 by four inclined boxsection bars 5 positioned angularly intermediate bars 4. Disc 3 is provided with a series of holes 3' for attachment directly to a tractor hub by means of the studs which would normally be employed to secure a tyred tractor wheel to the hub. A series of sixteen circumferentially equally spaced V-section bars 6 extend axially between side frames 1, 2 and have their opposite ends welded thereto. The bars are fabricated from 4 mm steel by folding to provide a 100 mm long limb 7 and a 90 mm long limb 8. The longer limb 7 extends at an angle of 300 to the local wheel radius, and the shorter limb 8 at an angle of 100, with the point 9 of the V being directed radially outwards and being flush with the radially outer edges of frames 1, 2. The direction of forward rotation of the wheel is indicated by the arrow B in Figure 1. CLAIMS

4. A tractor provided with a pair of wheels as claimed in any of the preceding claims in which the wheels are arranged such that, for forward movement, on contact with the ground the forward edge of the plate is radially outward of the rearward edge of the plate, to provide a wedging engagement with the ground.

5. A tractor wheel comprising two axially spaced apart circular frames rigidly connected by a series of circumferentially spaced ground engaging bars, the bars each being of substantially V-section with the point of the V directed radially outwardly of the wheel, one limb of the V being arranged to provide a wedging engagement with the ground for forward rotation of the wheel, and the other limb providing a wedging engagement for reverse rotation.

6. A tractor wheel as claimed in claim 5 in which said other limb is of shorter length than said one limb.

7. A tractor wheel as claimed in claim 5 or claim 6 in which said one limb is directed at an angle in the range substantially 250 to substantially 350 to a radius of the wheel.

8. A tractor wheel as claimed in claim 7 in which said angle is substantially 300.

9. A tractor wheel as claimed in any of claims 5 to 8 in which the angle between said other limb and a radius of the wheel is in the range substantially 50 to substantially 15 .

10. A tractor wheel as claimed in claim 9 in which said angle between said other limb and a radius of the wheel is substantially 100.

11. A tractor wheel substantially as described with reference to the accompanying drawings.

12. A tractor provided with a pair of wheels as claimed in any of claims 5 to 11.