AU707783B3 - Improvements to low loaders - Google Patents

Description

PETTY PATENT APPLICATION APPLICANT: CHASELING McGIFFIN PTY LTD TITLE: IMPROVEMENTS TO LOW LOADERS DATE FILED: 1 APRIL, 1999 BASED ON: PP9142 "IMPROVEMENTS TO LOW LOADERS" This invention relates to transport apparatus. It has particular but not exclusive application to heavy-duty low-loaders, but it is to be understood that it could be used in other applications, such as mobile rock-crushing plants and the like.

On mining sites, there is a need for rubber-tyred low-loaders to move large items of equipment from one part of the site to another. This is particularly the case for crawlermounted equipment, where excessive undercarriage wear can occur during extended travel. Such items of equipment can weigh over 300 tonnes.

To date, the low-loaders used to transport such equipment have been supported on a multiplicity of tyres small enough in diameter to fit beneath the platform. It is quite common to use 32 wheels, arranged in four rows of eight wheels each. A complex system 0 of load-equalisation apparatus connects the wheels together to ensure that the load is spread as evenly as possible over all of the wheels over a range of uneven road conditions, and brakes are provided for each wheel set. There are a number of disadvantages associated with this approach. Firstly, the equalisation system cannot function over a sufficient range of wheel travel to accommodate severe road irregularities, resulting in tyre and suspension damage. Secondly, the spread of support over such a large area results in severe tyre scrub during cornering, again damaging tyres and suspension components. Thirdly, the large number of small brakes (typically 16) used leads to problems of uniform application, and these brakes are inherently unsuited for continuous retardation on downgrades, as they overheat quickly.

2 Other rubber-tyred mining machinery has, over the years, been developed to use a small number of large wheels and brakes, and the latter has been developed to give oilcooled brakes which are highly effective for both emergency braking and retardation. To date, wheels and brakes of this design have not been applied widely to low-loaders because of their physical size. The tyres, which are typically up to 4 metres in diameter, are too large to fit beneath a load platform with a reasonable loading height. If they are installed outboard of the load platform, the vehicle becomes very wide, and cannot negotiate normal mine roads easily. If they are placed behind the load platform, it becomes impossible to load equipment over the rear of the load platform. While it is possible to load some types of equipment from the side, this is not feasible for long loads such as overburden drills. Low-loaders have been built with detachable goosenecks at the front of the load platform, allowing the prime mover and the gooseneck to be drive away from the platform so that loading can be carried out over the front edge of the load platform. While this design has been employed on some low-loaders, it is complex and requires very careful maneuvering on the part of the prime mover operator to realign with the load platform. Where oil-cooled brakes are used, there is a significant number of large oil hoses which must be disconnected and re-connected during the detachment and reattachment operation.

With the foregoing and other objects in mind, this invention in one aspect resides broadly in a low-loader of the type having a load platform supported at its front end from a prime mover by front support means and at its rear end by a left-hand wheel assembly and a right-hand wheel assembly, wherein each said wheel assembly includes a wheel yoke pivoted on a yoke pivot assembly to a rear corner of the load platform for movement between a travel position behind said load platform and a loading position substantially outboard of said load platform.

The yoke pivot assembly may have its yoke pivot axis vertical, such that the wheel assembly swings outboard with the wheels which are supported on the wheel assembly at a fixed height above the ground. It is preferred, however, that the yoke pivot axis be inclined to the vertical in such a way that the wheel assembly rises as it swings outboard, whereby the load platform may be lowered to the ground between the two wheel assemblies for ease of loading. The inclination of the yoke pivot axis may be in the longitudinal or transverse plane, or in a combination of both, provided that the object of raising the wheels above their travel position is achieved when they are moved outboard.

It is preferred, however, that the yoke pivot axis be contained in a plane parallel to the direction of travel of the vehicle such that minimal forces are required to hold the wheel assembly in the travel position, and be inclined upwards to the rear, whereby the desired raising of the wheel assembly occurs as it is swung outwards.

Platform jacks may be provided within or outboard of the load platform such that the rear end of the load platform may be raised to remove the load from the wheels before the wheel assemblies are moved into the loading position. The platform jacks may then be used to lower the rear end of the load platform towards ground level to facilitate loading.

The rear end of the load platform may be formed with a loading ramp to facilitate loading.

The wheel assemblies may be provided with latches or pinned connections such that they may be selectively locked in the travel position and held in that position against loads applied to the wheels.

In a further aspect, this invention resides in a method of constructing a low-loader, including:- 1. Providing a load platform supported at its front end from a prime mover by front support means; 2. Providing a left-hand wheel assembly and a right-hand wheel assembly, each said wheel assembly including a wheel yoke; 3. Pivotally attaching each said wheel assembly to a respective rear corner of said load platform via a yoke pivot assembly for movement of said wheel assembly between a travel position behind said load platform and a loading position substantially outboard of said.load platform.

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 a preferred embodiment of the invention, wherein:- Figure 1 is a side view of the rear end of a low-loader built according to the invention; Figure 2 is a rear view of the low-loader shown in Figure 1, showing the wheel assemblies in the travel position; Figure 3 is a rear view of the low-loader shown in Figure 1, showing the wheel assemblies in the loading position and the load platform lowered to the ground, and iJ{-L".

Figure 4 is a plan view of the low-loader shown in Figure 1, showing one wheel assembly in the travel position and one wheel assembly in the loading position.

The low-loader 10 shown in Figures 1 to 4 comprises a load platform 11 formed with yoke pivot assemblies 12 at its rear corners. To each yoke pivot assembly 12, a wheel yoke 13 is attached. Each wheel yoke 13 comprises an upper yoke pivot 14 and a lower yoke pivot 15 connected to a yoke frame 16 which extends inboard from the yoke pivots 14 and 15 in front of a dual-tyred stub axle assembly 17, then turns rearwards to support the inner end of the stub-axle assembly 17. The stub-axle assembly 17 carries one or two large tyres 20. The yoke pivots 14 and 15 are positioned in the same longitudinal plane, but the upper pivot 14 is placed to the rear of the lower pivot 15 so that the axis of rotation about the yoke pivots 14 and 15 is inclined upwards to the rear. An actuating hydraulic cylinder 21 is attached between the load platform 11 and each wheel yoke 13, and a hydraulic jack 22 is built into the load platform 11 in front of each rear corner. The rear end of the load platform 11 between the yoke pivot assemblies 12 is formed into a ramp 23.

Each wheel yoke frame 16 carries a locking tab 24 which engages with a travel lock 25 in the rear of the load platform 11. Cooling and actuation oil hoses 26 for the brakes 27 contained in each stub-axle assembly 17 are run from the load platform 11 to the brakes 27 along or within the yoke frames 16.

In use, the low-loader 10 is conducted to a loading area where an item of equipment is to be loaded by its prime mover (not shown). The rear end of the load platform 11 is then raised on the jacks 22 sufficiently for the tyres 20 to lift clear of the ground. The locks are released from the locking tabs 24, and the actuating cylinders 21 are then operated to swing the wheel yokes 13 outwards approximately 90 degrees. Because of the inclination of the yoke pivot axes, the tyres 20 lift above the lower edge of the load platform 11 as they swing outwards. The rear end of the load platform 11 can then be lowered by the jacks 22 until the lower edge of the ramp 23 is close to ground level. The equipment can then be driven aboard the load platform 11. The latter is then raised on the jacks 22, allowing the wheel yoke 13 to be swung inboard by the actuating cylinders 21 and locked in position by engagement between the tabs 24 and the locks 25. The jacks 22 are then retracted and the low-loader 10 can drive away.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is herein set forth.

Claims (3)

1. A low-loader of the type having a load platform supported at its front end from a prime mover by front support means and at its rear end by a left-hand wheel assembly and a right-hand wheel assembly, wherein each said wheel assembly includes a wheel yoke pivoted on a yoke pivot assembly to a rear corner of the load platform for movement between a travel position behind said load platform and a loading position substantially outboard of said load platform, wherein said yoke pivot assembly has an axis of rotation inclined to the vertical in such a way that the wheel assembly rises as it swings outboard, and wherein there is provided one or more jacks attached to the load platform and engaging with the ground for supporting the rear end of said platform while each said wheel assembly moves between the travel and loading positions.

2. A low-loader as described in Claim 1, wherein said yoke pivot axis is contained in a plane parallel to the direction of travel of the vehicle and is inclined upwards to the rear.

3. A low-loader as described in Claim 1 or Claim 2, wherein there are provided actuating cylinders for selectively moving said wheel assemblies between the travel and loading positions. DATED THIS Fifth DAY OF May 1999 CHASELING McGIFFIN PTY LTD