AU3784500A - Improved endless track undercarriage assembly - Google Patents

Description

-4 P/00/011 Regulation 3.2 COMMONWEALTH OF AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventor(s): Address for Service: McLEAN AGOUIP HOLDINGS PTY LTD McLEAN AGQUIP HOLDINGS PTY LTD

AHEARNS

Patent Trade Mark Attorneys GPO Box 1149 Brisbane Queensland 4001 "IMPROVED ENDLESS TRACK UNDERCARRIAGE

ASSEMBLY"

Invention Title: The following statement is a full description of this invention, including the best method of performing it known to us: -1- "IMPROVED ENDLESS TRACK UNDERCARRIAGE ASSEMBLY" THIS INVENTION relates to an improved endless track undercarriage assembly.

The invention has particular application to undercarriage assemblies for agricultural equipment of the type drawn by a tractor in open fields and for illustrative purposes, reference will be made to such application. However, it is to be understood that this invention could be used in applications where an undercarriage assembly supports a towed vehicle on public roads and highways in which case they may be drawn by a tractor, truck, or other prime mover. This invention may also be used in military applications where an undercarriage assembly supports a towed vehicle adapted for use on a wide range of terrains.

Agricultural equipment supported on endless track undercarriage assemblies has been provided by various manufacturers. For example, the "CATERPILLAR VS AGRICULTURAL EQUIPMENT CATALOGUE", published 1995 shows various arrangements for agricultural equipment supported on two similar types of 20 endless track undercarriage assembly (with the part numbers and VFS70), each assembly including respective pairs of endless track assemblies (or crawler track assemblies as they are commonly called), a chassis frame and a hitch adapted for hitching to a towing vehicle.

Typically, each endless track assembly includes an endless track in the form of a belt or chain which passes around two wheels and one or more idler wheels in between the end wheels, generally of a smaller diameter than the end wheels, but arranged for spreading the load. Typically, the two crawler track -2assemblies are connected together by a cross member which is adapted to be fixed to the underside of the vehicle chassis, each crawler track assembly being allowed limited up and down pivotal movement (or oscillation) relative to the cross member.

Endless track undercarriage assemblies have significant advantages over traditional wheeled vehicles, including a significantly larger footprint and significantly lower axle loads as set forth for example in the above mentioned trade catalogue.

However, one of the problems of the endless track undercarriage assemblies of the prior art is that in some circumstances, manoeuvring over soft or rough ground may cause the two crawler track assemblies to tow inwardly or splay outwardly in the direction of travel rather than run in parallel with one another.

This effect increases the draw bar tension and towing power requirements for the towing vehicle, and in some circumstances, ~may damage the undercarriage assembly.

Once a threshold vehicle mass is exceeded, regulatory authorities often require that, for safety, the towed vehicle eoo.

must be fitted with an approved braking mechanism operable from 20 or by the towing vehicle. Vehicles fitted with crawler track assemblies have been limited in size because it has been difficult to fit brakes to such vehicles. Another problem with prior art crawler track assemblies is that the amount of independent up and down pivoting between the crawler track assemblies has been limited. For example, the CATERPILLAR brand and VFS50 undercarriage assemblies shown in the above mentioned trade catalogue are said to accommodate a 170 oscillation. Although this may be adequate for many applications, -3it will be appreciated that greater oscillation will increase the versatility and stability of such undercarriage assemblies.

Systems traditionally used to limit the inward tow or outward splay of the crawler track assemblies usually provide a strut between each crawler track assembly and the cross member connecting the two crawler track assemblies. Oscillation of the crawler track assemblies causes the strut to traverse an arcuate sweeping course with respect to the frame which exacerbates the inward tow and outward splay of the crawler track assemblies if the oscillation is allowed to exceed approximately 170.

With the foregoing in view, this invention resides broadly an improved endless track undercarriage assembly including: a pair of crawler track assemblies mounted on respective coaxial transverse dead axles for supporting a towed vehicle body, and alignment means associated with each crawler track assembly, each alignment means having a first part connected to its respective crawler track assembly and a second part on or connected to the vehicle body, said first and second parts being 20 co-operable with one another for preventing undesirable inward towing and outward splaying of the crawler track assemblies.

Preferably, each alignment means prevents the front of its associated crawler track assembly from undesirably splaying out and towing in by operative engagement of the first and second parts, and more preferably, the first and second parts are arranged to cooperate with one another remote from the dead axles in order to attract less of a mechanical disadvantage than would be the case if they were located close to the dead axles.

-4- Preferably, the first part includes front abutment means extending inwardly from a front portion of each crawler track assembly and rear abutment means extending inwardly from a rear portion of each crawler track assembly, the front and rear abutment means being abuttable against corresponding side portions of the towed vehicle body remote from the axis of the dead axles, the corresponding side portions constituting the second part or parts.

The front and rear abutment means preferably each include a wheel or roller on their respective distal extremities which are adapted to engage in rolling relationship with a respective wear S" plate on the respective side portions of the towed vehicle body.

Suitably, the wheel or roller is oriented to roll in the direction of relative movement between the vehicle and the front 15 and rear portions of the crawler track assemblies.

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It is further preferred that limitation means be provided limiting the amount of oscillation of the respective crawler track assemblies about the axis of the dead axles so that the

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wheels or rollers cannot roll off the wear plates, however, the 20 limitation means may also be adjusted to limit the oscillation of the respective crawler track assemblies to prevent them from striking any overhanging body work on the towed vehicle body.

The wear plate may be mounted on the side of the towed vehicle body itself, or where a chassis is provided, the wear plate may be mounted on the chassis. Where rollers are provided for the front and rear abutment means, the rollers may be in constant engagement with the wear plates limiting the inward towing and outward splaying of the crawler tracks substantially to zero. Moreover, the constant engagement may include a biassing force. However, in some arrangements, it may be desirable to arrange the abutment means a small distance from the wear plates, the crawler track assemblies being allowed to tow inward or splay outward within a desired tolerance, or the rollers may be mounted to accommodate some movement of the roller towards or away from the respective crawler track assemblies corresponding to the inward towing and outward splaying within such tolerance.

In another aspect, this invention resides broadly in a method of preventing undesirable inward towing and outward splaying of two crawler track assemblies supporting a towed vehicle such that the crawler track assemblies may oscillate about a transverse axis, the method including: providing alignment means associated with each crawler track assembly, each alignment means having a first part connected to B e6 ~its respective crawler track assembly and a second part on or connected to the vehicle body, the first and second parts being remote from the transverse axis; engaging the first parts with their respective second parts 20 to limit the amount of towing in and splaying out of each crawler track assembly.

In another aspect, this invention resides broadly in a towed vehicle having an undercarriage assembly including alignment means as hereinbefore described.

In another aspect, this invention resides broadly in a towed vehicle including: a vehicle body supported on crawler track assemblies, each crawler track assembly including an endless track drivably -6engaged with two or more wheels mounted on respective fixed axles, and braking apparatus including a wheel mountable part mounted on one of the wheels for rotation therewith; a fixed part mounted on the respective axle, said fixed part including braking means adapted to selectively engage the wheel mountable part to brake the wheel.

In another aspect, this invention resides broadly in braking apparatus for a towed vehicle having an endless track undercarriage assembly having a pair of crawler track assemblies each including an endless track drivably engaged with two or more wheels mounted on respective fixed axles, said braking apparatus including: S 15 a wheel mountable part mountable on one of the wheels for rotation therewith, said wheel mountable part having a friction eeo* ooo surface; a fixed part mountable on the fixed axle for said wheel, said fixed part including engagement means adapted to engage said friction surface, and actuation means for actuating said engagement means so as to engage with said friction surface.

In another aspect, this invention resides broadly in an endless track undercarriage assembly for supporting a vehicle body, the undercarriage assembly including two or more crawler track assemblies and each crawler track assembly including an endless track drivably engaged with two or more wheels mounted on respective fixed axles and braking apparatus including a wheel mountable part mounted on one of the wheels for rotation therewith; a fixed part mounted on the respective axle, said fixed part including braking means adapted to selectively engage the wheel mountable part to brake the wheel.

The mounting of the fixed part on the axle is preferably achieved by providing an extended axle or an axle stub extension to the axle, the stub being attached to the fixed axle by a splined or keyed connection.

Preferably, the rotatable part is in the form of a drum and the engagement means is in the form of one or more brake shoes having brake pads adapted for braking engagement with the friction surface of the drum.

*"The actuation means is preferably a hydraulic or compressed 15 air or vacuum over hydraulic type actuator in accordance with known art, and is preferably mounted on with the engagement means on the non-rotatable stub extension.

In another aspect, this invention resides broadly in a towed vehicle including braking apparatus and alignment means as oe hereinbefore described.

In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate preferred embodiments of two aspects of the invention, and wherein: Fig. 1 is a cross-sectional, diagrammatic view of a crawler track assembly near an idler wheel, and Fig. 2 is a cross-sectional, diagrammatic view of the crawler assembly of Fig. 1 through an end wheel.

-8- Referring to Fig. 1, a crawler track assembly 10 includes an endless belt 11 passing around two end wheels (not shown) and one or more idler wheels 12 mounted for supporting a crawler frame 13 for a towed vehicle body (not shown). Remote from a dead axle (not shown) there is provided an abutment assembly 16 towards the front and rear the crawler track assembly (only one of which is shown).

The crawler track assembly 10 supports a chassis frame having a longitudinal frame member 14. A side portion 19 of the longitudinal frame member 14 adjacent the abutment assembly 16 has attached to it a wear plate 17. The abutment assembly 16 includes an abutment wheel 18 which engages with the wear plate 17 when the front or rear portion, as the case may be, of the crawler track assembly moves towards the longitudinal frame 15 member 14 in the direction of the arrow shown at 15. Such movement, if unchecked by the abutment of the abutment wheel against the wear plate would result in undesirable towing in or splaying out of the crawler track assemblies.

The crawler frame 13 also includes a limitation arm 21 extending inwardly from the crawler frame 13 and the limitation arm 21 is further supported by a support bracket 23. The limitation arm is limited in its upward movement in the direction of the arrow shown at 20 relative to the longitudinal frame member 14 by abutment against a portion of the longitudinal frame member 14.

Referring to Fig. 2, a brake assembly 30 is mounted on the outer one of a pair of end wheels 25 which are rotatable on a fixed axle 26 by way of two pairs of sets of roller bearings 28.

-9- The brake assembly 30 includes a drum 32 mounted for rotation on the outer one of the end wheels 25, and a pair of brake shoes 34 mounted fixedly for selective braking engagement with the drum 32 and actuated by an actuator. The brake assembly is closed by a fixed closure plate assembly 36 mounted on an axle stub extension keyed for non-rotation to the end of the fixed axle 26. In another form, the drum could be replaced by a disc and the brake shoes by a caliper assembly in known manner.

Although the invention has been described with reference to one or more specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms and fall within the broad scope and ambit of this invention as claimed by the following claims.

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Claims (18)

1. An improved endless track undercarriage assembly including: a pair of crawler track assemblies mounted on respective coaxial transverse dead axles for supporting a towed vehicle body, and alignment means associated with each crawler track assembly, each alignment means having a first part connected to its respective crawler track assembly and a second part on or connected to the vehicle body, said first and second parts being co-operable with one another for preventing undesirable inward towing and outward splaying of the crawler track assemblies. **ee

2. An endless track undercarriage assembly according to Claim 1, wherein each alignment means prevents the front of its associated crawler track assembly from undesirably splaying out and towing in by operative engagement of the first and second parts.

3. An endless track undercarriage assembly according to Claim 1 or Claim 2, wherein the first and second parts are arranged to cooperate with one another remote from the dead axles.

4. An endless track undercarriage assembly according to any one of the preceding claims, wherein the first part includes front abutment means extending inwardly from a front portion of each crawler track assembly and rear abutment means extending inwardly from a rear portion of each crawler track assembly, the front and -11- rear abutment means being abuttable against corresponding side portions of the towed vehicle body remote from the axis of the dead axles, the corresponding side portions constituting the second part or parts.

An endless track undercarriage assembly according to any one of the preceding claims, wherein the front and rear abutment means each include a wheel or roller adapted to engage in rolling relationship with a respective wear plate on the respective side portions of the towed vehicle body.

6. An endless track undercarriage assembly according to any one of the preceding claims, and including limitation means for limiting the amount of oscillation of the respective crawler track assemblies about the axis of the dead axles.

7. An endless track undercarriage assembly for supporting a vehicle body, the undercarriage assembly including two or more *crawler track assemblies and each crawler track assembly including an endless track drivably engaged with two or more wheels mounted on respective fixed axles and braking apparatus including a wheel mountable part mounted on one of the wheels for rotation therewith; a fixed part mounted on the respective axle, said fixed part including braking means adapted to selectively engage the wheel mountable part to brake the wheel. -12-

8. An endless track undercarriage assembly according to any one of the preceding claims, wherein the fixed part is mounted on an axle stub attached to the axle.

9. A towed vehicle having an undercarriage assembly including an endless track undercarriage assembly according to any one of the preceding claims.

A towed vehicle including: a vehicle body supported on crawler track assemblies, each crawler track assembly including an endless track drivably engaged with two or more wheels mounted on respective fixed axles, and braking apparatus including a wheel mountable part mounted on one of the wheels for rotation therewith; a fixed part mounted on the respective axle, said fixed part including braking means adapted to selectively engage the wheel mountable part to brake the wheel.

11. A method of preventing undesirable inward towing and outward splaying of two crawler track assemblies supporting a towed vehicle such that the crawler track assemblies may oscillate about a transverse axis, the method including: providing alignment means associated with each crawler track assembly, each alignment means having a first part connected to its respective crawler track assembly and a second part on or connected to the vehicle body, the first and second parts being -13- remote from the transverse axis; engaging the first parts with their respective second parts to limit the amount of towing in and splaying out of each crawler track assembly.

12. Braking apparatus for a towed vehicle having an endless track undercarriage assembly having a pair of crawler track assemblies each including an endless track drivably engaged with two or more wheels mounted on respective fixed axles, said braking apparatus including: a wheel mountable part mountable on one of the wheels for rotation therewith, said wheel mountable part having a friction ""surface; a fixed part mountable on the fixed axle for said wheel, said fixed part including engagement means adapted to engage said friction surface, and actuation means for actuating said engagement means so as to engage with said friction surface.

13. Braking apparatus according to Claim 12, wherein the rotatable part is in the form of a drum and the engagement means is in the form of one or more brake shoes having brake pads adapted for braking engagement with the friction surface of the drum.

14. Braking apparatus according to Claim 12 or Claim 13, wherein the actuation means includes a hydraulic or compressed air or vacuum over hydraulic type actuator mounted with the engagement -14- means on the non-rotatable stub extension.

A towed vehicle including braking apparatus according to any one of Claims 12 to 14.

16. A towed vehicle including braking apparatus according to any one of Claims 12 to 14 and an endless track undercarriage assembly according to any one of Claim 1 to 8.

17. An endless track undercarriage assembly substantially as hereinbefore described with reference to Fig. 1.

18. An endless track undercarriage assembly substantially as hereinbefore described with reference to Fig. 2. Dated this 1 s day of June, 2000 McLEAN AGOUIP PTY LTD by their Patent Attorneys AHEARNS