GB1604615A - Tractors - Google Patents

Tractors Download PDF

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Publication number
GB1604615A
GB1604615A GB2298777A GB2298777A GB1604615A GB 1604615 A GB1604615 A GB 1604615A GB 2298777 A GB2298777 A GB 2298777A GB 2298777 A GB2298777 A GB 2298777A GB 1604615 A GB1604615 A GB 1604615A
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Prior art keywords
track
tractor
means
wheels
fig
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB2298777A
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Shelton P A
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D49/00Tractors
    • B62D49/06Tractors adapted for multi-purpose use
    • B62D49/0621Tractors adapted for multi-purpose use comprising traction increasing arrangements, e.g. all-wheel traction devices, multiple-axle traction arrangements, auxiliary traction increasing devices
    • B62D49/0635Tractors adapted for multi-purpose use comprising traction increasing arrangements, e.g. all-wheel traction devices, multiple-axle traction arrangements, auxiliary traction increasing devices using additional ground engaging means, e.g. endless tracks

Description

(54) IMPROVEMENTS IN OR RELATING TO TRACTORS (71) I, PETER ALFRED SHELTON, a British Subject, of Can Magret, Capdella, Palma de Mallorca, Spain, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to tractors suitable for use in farming.

According to the present invention there is provided a wheeled tractor convertible into a crawler by means of two tracks mounted on opposite sides of the tractor with the aid of supporting and guiding frames pivotally mounted for rotation about an axis coaxial with or adjacent and parallel to the axis of the rear wheels of the tractor, the respectve tracks being tensioned around the tyres of the rear wheels and idler wheels or guides mounted on the respective frames, the ground-engaging parts of the tracks being of rubber or other elastomeric material, means being provided whereby the frames can be pivoted between a first, up, position in which the front wheels of the tractor engage the ground and the tractor can be used as a wheeled tractor to a second, down position in which the front wheels of the tractor are lifted from the ground and the tractor is supported through the tracks for use as a crawler, and track-engaging, load-bearing means being provided on the frames intermediate the rear wheels and the idler wheels or gudes to take load when the tractor is in use as a crawler.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figs. 1 and 2 show schematically one embodiment of the invention, Fig. 3 shows part of one embodiment of the invention in more detail, Fig. 4 shows part of another embodiment of the invention, Fig. 5 shows a preferred form of a flexible track for use in an embodiment of the invention, Fig. 6 shows part of the flexible track of Fig. 5 in cross-section, Fig. 7 shows in cross-section part of the track of Fig. 5 cooperating with a preferred form of rear wheel with two tyres, Fig. 8 shows in cross-section part of an alternative form of flexible track, Fig. -9 shows in perspective part of the flexible track of Fig. 8, Fig. 10 shows in perspective part of another alternative form of flexible track, Fig. 11 shows in cross-section an idler wheel and associated flexible track, and Fig. 12 shows an alternative to the arrangement of Fig. 11.

Referring to Figs. 1 and 2 a wheeled tractor 10 has rear wheels 11 and front wheels 12, the rear wheels 11 also having tracks 13 or guides 14 on the supporting and guiding frames 15. The latter are pivoted for rotadriven thereby and passing around idler wheels tion about the axis of the rear wheels 11 or an axis adjacent to and parallel to the axis of the rear wheels. For example the axis about which the frame 15 can pivot may be somewhat forward of the axis of the rear wheels 11.

Any suitable means such as hydraulic rams (not shown in Figs. 1 and 2) are provided whereby the frames 15 can be pivoted between a first, up position shown in Fig. 1 in which the front wheels 12 engage the ground 16 and a second, down position shown in Fig. 2 in which the front wheels of the tractor are lifted from the ground.

With the frames 15 in the position shown in Fig. 1 and hence the front wheels 12 on the ground the tractor 10 can be handled substantially as a normal wheeled tractor.

The tracks 13 are driven by the rear wheels 11 and pass between the rear wheels and the ground but apart from this provide no support and traction. However with the frames in the position shown in Fig. 2 in which the front wheels 12 are lifted from the ground the tractor is supported wholly through the tracks 13 and can then be used as a crawler.

The tracks 13 are made of flexible mat erial which also carries a tread. In a simple form of the tracks each consists of a loop of flexible but substantially inextensible belt to which rubber treads are vulcanized.

The supporting and guiding frames 15 may be as shown in Fig. 3 in which they are pivoted about the axis of the rear wheels.

The lowermost stretch of the frame 15 shown has guiding skirts 17 between which the track 13 is guided. Rollers shown in broken lines at 18 are provided between the skirts 17 and the tractor is supported by the rollers 18 acting through the track.

A track-tensioning roller 24 acts between the frame 15 and the track 13 and a hydraulic ram shown in broken lines at 19 is provided for pivoting the frame between its up and down positions.

To locate the track 13 on the tyre of the wheel 11 the tyre can be provided with a radial flange (not shown) on each side.

In another arrangement the track is provided with a central groove along its inner, tyreengaging face and the tyre is provided with a central radial flange for engagement with the groove in the track. By doming the profile of the tyre to cause a tendency for the track to centre itself automatically on the tyre and by providing the mating groove and flange, retention of the tracks on the tyres of the rear wheels is assured.

In another arrangement shown in Fig. 4 the rollers 18 of Fig. 3 are replaced by two rollers 20 and 21 and a loop of belt 22 which is tensioned. One of the rollers 20 and 21 can be driven to move the belt 22 at the same speed as the track 13 and if needed a third roller 23 can be provided intermediate the rollers 20 and 21. As an alternative to the third roller a skid or skids intermediate the rollers 20 and 21 can be used.

Various other arrangements are visualized for supporting and guiding a flexible track.

In one of these the tyre on each of the rear wheels has a circumferential groove of semicircular cross-section and the tracks are of moulded rubber or other elastomeric material.

Each track also has groove of semi-circular cross-section whereby when it is face-to-face with the groove in the tyre a channel of circular cross-section is defined. The track supporting and guiding frames have steel channels therein also of semicircular crosssection and facing the groove in the track whereby a closed loop of channel is provided of circular transverse cross-section.

This channel is filled with spherical balls of substantially the same diameter as the transverse diameter of the channel through which the track is supported and guided throughout its length.

In a modification of this the channel instead of extending around the rear wheel is provided solely in a closed loop on the frame.

In applying the invention it is preferred to employ tracks in the form of reinforced rubber or belts with rubber vulcanized thereon.

By means of the present invention a tractor can be provided which can be used as a wheeled tractor or as a crawler at a fraction of the combined cost of a separate wheeled tractor and a crawler.

When the machine is used as a crawler steering is accomplished by means of the known technique of a hydraulic ram or rams in the linkage between the rear of the machine and the plough or other implement towed by the machine.

Referring now to Fig. 5 this shows a preferred form of the track 13, the rear wheel 11 and the idler wheel 14 in greater detail.

The track 13 comprises a closed loop of flexible belt 16 to which a rubber tread 17 is vulcanized, preferably in a chevron pattern.

On the inner face of the belt 16 guide means 18 are arranged, spaced apart along the belt.

The guide means 18 are metallic members projecting inwardly from the belt 16.

The guide means 18 are shown in Fig. 6.

Each member is of triangular cross-section and may be made by bending a plate of metal to form a hollow triangular prism. The guide means 18 are fixed to the belt 16 using bolts 19.

Fig. 7 shows the arrangement of the track 13 on the rear wheel 11. The rear wheel 11 comprises a first rim 20 mounted on the wheel-hub and a second rim 21 mounted on the first rim 20 by means of struts 22.

Arranged on the rims 20 and 21 are tyres 23 which are of such a shape as to cause doming of the track 13 to assist in retaining the track on the rear wheel 11. Preferably the rims and tyres are produced in matched pairs and the tyres are connected to a single valve to ensure equal pressures whereby the track is supported equally by both tyres.

During use of the tractor mud, clay and the like tend to accumulate on the track 13 and pack between the track and the tyres 23, so raising the track away from the tyres. It may be advantageous to reduce the area of contact between the belt 16 and the tyres 23, for example by use of two narrow inwardly projecting longitudinal ribs on the track 16 to engage the tyres. A high pressure is thus produced over the area of contact and mud is forced out from between the belt and the tyres. The guide means 18 of the track 13 are received in the channel between the tyres 23. In an alternative embodiment of the invention to that shown in Fig. 7 the guide meas 18 may be of such size and spacing as to engage the struts 22. This arrangement would provide drive for the track 13 when slippage might occur between the belt 16 and the tyres 23.

Fig. 8 and 9 show another example of the guide means 18 comprising metallic members spaced apart along the belt 16. Each member is again substantially triangular in crosssection but the lower edge 25 of each sideplate is in the form of an arc of a circle.

Each member is fixed to the belt 16 by bolts 19 through a bridge 24 joining the two side-plates. Preferably the radius of curvature of the lower edges 25 is the same as the radius of the idler wheel 14. This reduces wear of the belt 16 by allowing it to flex uniformly as it passes around the idler wheel 14.

Fig. 10 shows an alternative type of guide means comprising a length of spring steel 26 fixed to the belt 16 by means of plates 27 and bolts 28. The length of spring steel 26 has its ends joined together to form a continuous spring on the inner surface of the belt 16. The portion of the spring in contact with the belt are perpendicular to the longitudinal axis of the belt so that they are not required to bend when passing around the rear wheel 11 or the idler wheel 14.

Fig. 11 shows an idler wheel 14 in contact with the track 13. The idler wheel 14 comprises two dished members 29 fixed to a hub 30 which is mounted on a spindle 31.

The surfaces of the members 29 which engage the belt 16 are shaped to cause doming of the belt to assist in retaining the track 13 on the idler wheel 14. These surfaces may also be provided with holes to allow mud and the like to clear from between the belt 16 and the members 29 where it tends to accumulate. The channel between the two members 29 receives the guide means 18 of the track 13.

Fig. 12 shows a similar idler wheel 14 comprising two dished members 32 mounted on a hub 33. The guide means 18 of the track 13 are received in a channel between the two members 32.

WHAT I CLAIM IS:- 1. A wheeled tractor convertible into a crawler by means of two tracks mounted on opposite sides of the tractor with the aid of supporting and guiding frames pivotally mounted for rotation about an axis coaxial with or adjacent and parallel to the axis of the rear wheels of the tractor, the respective tracks being tensioned around the tyres of the rear wheels and idler wheels or guides mounted on the respective frames, the groundengaging parts of the tracks being of rubber or other elastomeric material, means being provided whereby the frames can be pivoted between a first, up, position in which the front wheels of the tractor engage the ground and the tractor can be used as a wheeled tractor to a second, down position in which the front wheels of the tractor are lifted from the ground and the tractor is supported through the tracks for use as a crawler, and track-engaging, load-bearing means being provided on the frames intermediate the rear wheels and the idler wheels or guides to take load when the tractor is in use as a crawler.

2. A tractor according to claim 1, wherein the means for pivoting the said frames comprise hydraulic rams.

3. A tractor according to claim 1 or 2, wherein the track-engaging, load-bearing means comprise rollers journalled in the said frames and arranged to act between the tracks and the said frame to take load when the frames are in the said down position.

4. A tractor according to claim 1, 2 or 3, wherein each track has locating means projecting inwardly from the inner face thereof, each idler wheel or guide has a channel therein to receive the locating means of its associated track, and each rear wheel has two coaxial tyres spaced from one another to provide a circumferential channel receiving the locating means of its associated track.

5. A tractor according to claim 4 wherein the locating means comprise a multiplicity of inwardly directed locating members spaced from one another around the loop of track.

6. A tractor according to claim 5, wherein the locating members when viewed along the track are of generally triangular form with the base of the triangle affixed to the track.

7. A tractor according to claim 4, wherein the locating means comprise a continuous length of spring steel shaped into a series of spaced transverse sections articulated to the inner face of the track and interconnected by loops.

8. A tractor substantially as hereinbefore described with reference to Figs. 1 and 2 in conjunction with, Fig. 3, or Fig. 4, or Figs.

5, 6 and 7, or Figs. 8 and 9, or Figs. 5, 6, 7 and 11, or Figs. 5, 6, 7 and 12 of the accompanying drawings.

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

Claims (8)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    guide means 18 comprising metallic members spaced apart along the belt 16. Each member is again substantially triangular in crosssection but the lower edge 25 of each sideplate is in the form of an arc of a circle.
    Each member is fixed to the belt 16 by bolts 19 through a bridge 24 joining the two side-plates. Preferably the radius of curvature of the lower edges 25 is the same as the radius of the idler wheel 14. This reduces wear of the belt 16 by allowing it to flex uniformly as it passes around the idler wheel 14.
    Fig. 10 shows an alternative type of guide means comprising a length of spring steel 26 fixed to the belt 16 by means of plates 27 and bolts 28. The length of spring steel 26 has its ends joined together to form a continuous spring on the inner surface of the belt 16. The portion of the spring in contact with the belt are perpendicular to the longitudinal axis of the belt so that they are not required to bend when passing around the rear wheel 11 or the idler wheel 14.
    Fig. 11 shows an idler wheel 14 in contact with the track 13. The idler wheel 14 comprises two dished members 29 fixed to a hub 30 which is mounted on a spindle 31.
    The surfaces of the members 29 which engage the belt 16 are shaped to cause doming of the belt to assist in retaining the track
    13 on the idler wheel 14. These surfaces may also be provided with holes to allow mud and the like to clear from between the belt 16 and the members 29 where it tends to accumulate. The channel between the two members 29 receives the guide means 18 of the track 13.
    Fig. 12 shows a similar idler wheel 14 comprising two dished members 32 mounted on a hub 33. The guide means 18 of the track 13 are received in a channel between the two members 32.
    WHAT I CLAIM IS:- 1. A wheeled tractor convertible into a crawler by means of two tracks mounted on opposite sides of the tractor with the aid of supporting and guiding frames pivotally mounted for rotation about an axis coaxial with or adjacent and parallel to the axis of the rear wheels of the tractor, the respective tracks being tensioned around the tyres of the rear wheels and idler wheels or guides mounted on the respective frames, the groundengaging parts of the tracks being of rubber or other elastomeric material, means being provided whereby the frames can be pivoted between a first, up, position in which the front wheels of the tractor engage the ground and the tractor can be used as a wheeled tractor to a second, down position in which the front wheels of the tractor are lifted from the ground and the tractor is supported through the tracks for use as a crawler, and track-engaging, load-bearing means being provided on the frames intermediate the rear wheels and the idler wheels or guides to take load when the tractor is in use as a crawler.
  2. 2. A tractor according to claim 1, wherein the means for pivoting the said frames comprise hydraulic rams.
  3. 3. A tractor according to claim 1 or 2, wherein the track-engaging, load-bearing means comprise rollers journalled in the said frames and arranged to act between the tracks and the said frame to take load when the frames are in the said down position.
  4. 4. A tractor according to claim 1, 2 or 3, wherein each track has locating means projecting inwardly from the inner face thereof, each idler wheel or guide has a channel therein to receive the locating means of its associated track, and each rear wheel has two coaxial tyres spaced from one another to provide a circumferential channel receiving the locating means of its associated track.
  5. 5. A tractor according to claim 4 wherein the locating means comprise a multiplicity of inwardly directed locating members spaced from one another around the loop of track.
  6. 6. A tractor according to claim 5, wherein the locating members when viewed along the track are of generally triangular form with the base of the triangle affixed to the track.
  7. 7. A tractor according to claim 4, wherein the locating means comprise a continuous length of spring steel shaped into a series of spaced transverse sections articulated to the inner face of the track and interconnected by loops.
  8. 8. A tractor substantially as hereinbefore described with reference to Figs. 1 and 2 in conjunction with, Fig. 3, or Fig. 4, or Figs.
    5, 6 and 7, or Figs. 8 and 9, or Figs. 5, 6, 7 and 11, or Figs. 5, 6, 7 and 12 of the accompanying drawings.
GB2298777A 1978-05-30 1978-05-30 Tractors Expired GB1604615A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2298777A GB1604615A (en) 1978-05-30 1978-05-30 Tractors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2298777A GB1604615A (en) 1978-05-30 1978-05-30 Tractors

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GB1604615A true true GB1604615A (en) 1981-12-09

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GB2298777A Expired GB1604615A (en) 1978-05-30 1978-05-30 Tractors

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4844560A (en) 1987-10-28 1989-07-04 Edwards, Harper, Mcnew & Company Endless drive track joint assembly
US4861120A (en) 1987-05-14 1989-08-29 Edwards, Harper, Mcnew & Company Modular endless track drive system and methods of making, installing and repairing same
US4884852A (en) 1987-05-14 1989-12-05 Edwards, Harper, Mcnew & Company Double V-shaped endless track drive system
US4906054A (en) 1987-05-14 1990-03-06 Edwards, Harper, Mcnew & Company Endless track drive system
USRE33324E (en) 1983-07-25 1990-09-04 Edwards, Harper, McNew & Co. Endless drive system
US5005922A (en) 1987-05-14 1991-04-09 Edwards, Harper, Mcnew & Company Double V-shaped endless track drive system
US5005921A (en) 1987-05-14 1991-04-09 Edwards, Harper, Mcnew & Company Endless track drive system
US5020865A (en) 1988-01-20 1991-06-04 Edwards, Harper, Mcnew & Company Endless drive track joint assembly
US5040282A (en) 1987-05-14 1991-08-20 Edwards, Harper, Mcnew & Company Method of making a modular endless track drive system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE33324E (en) 1983-07-25 1990-09-04 Edwards, Harper, McNew & Co. Endless drive system
US5005921A (en) 1987-05-14 1991-04-09 Edwards, Harper, Mcnew & Company Endless track drive system
US4861120A (en) 1987-05-14 1989-08-29 Edwards, Harper, Mcnew & Company Modular endless track drive system and methods of making, installing and repairing same
US4884852A (en) 1987-05-14 1989-12-05 Edwards, Harper, Mcnew & Company Double V-shaped endless track drive system
US4906054A (en) 1987-05-14 1990-03-06 Edwards, Harper, Mcnew & Company Endless track drive system
US5005922A (en) 1987-05-14 1991-04-09 Edwards, Harper, Mcnew & Company Double V-shaped endless track drive system
US5040282A (en) 1987-05-14 1991-08-20 Edwards, Harper, Mcnew & Company Method of making a modular endless track drive system
US4844560A (en) 1987-10-28 1989-07-04 Edwards, Harper, Mcnew & Company Endless drive track joint assembly
US5020865A (en) 1988-01-20 1991-06-04 Edwards, Harper, Mcnew & Company Endless drive track joint assembly

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee