AU2013284344A1 - Improved brake testing apparatus - Google Patents

Abstract

A roller brake testing apparatus (10) comprises a base frame (12), at least one sub-frame, (16, 18), typically slideably mounted on the base frame (12), the sub- frame (16, 18) supporting a first and a second pair of rollers (20, 22) each having a diameter of 110mm to 155mm, arranged to be driven by a control means including a motor (100). At least one of the sub-frames (16, 18) carrying the pair of rollers may be moved towards and/or away from the second pair of rollers. The control means is arranged to measure or calculate the force or torque applied to turn the rollers to determine either the rolling resistance of the wheels, or the braking force if the brakes are applied. The movement of the sub-frame towards and/or away from the second pair of rollers allows the apparatus to be used with vehicles of differing axle length/wheel track width, enabling the same apparatus to be used with both on road vehicles and off road vehicles having relatively larger wheel track width. The apparatus also includes a wheel shaking assembly (26, 28).

Description

WO 2014/000035 PCT/AU2013/000690 "Improved brake testing apparatus" Cross-Reference to Related Applications The present application claims priority from Australian Provisional Patent Application No 2012902767 filed on 28 June 2012, the content of which is 5 incorporated herein by reference. Field of the Invention This invention relates to an improved brake testing apparatus and in particular to an improved roller brake tester (RBT), also known as a roller dynamometer. 10 Background of the Invention Routine brake testing is important, particularly for commercial heavy vehicles, to ensure that their brakes are properly maintained and operating according to their original specification. Brake testing is typically performed using a roller dynamometer 15 which includes two sets of rollers which are driven by powerful hydraulic motors. A vehicle whose brakes are to be tested is driven onto the roller assembly one axle at a time. Each wheel on the axle being tested sits in between a set of rollers. During a brake test, the rollers turn the wheels, and the effort required to turn each wheel is measured and recorded. If the brakes are applied, this measures the braking force of 20 the wheel. If the brakes are not applied, the wheel drag, or rolling resistance, is measured. Within the commercial vehicle sector, roller brake testers are used to test vehicles within a broad size and weight range, set out in various road safety standards. However, as well as testing of commercial vehicles which are used "on-road', certain 25 vehicles including those which are predominately used "off-road" are also subject to brake testing, although they are not covered by the same standards that apply to on road vehicles. Such vehicles are usually much larger than vehicle used on the highway and special, non-standard equipment is required to test their brakes. This creates a substantial additional cost for companies that operate both on and off road vehicles. 30 Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application. 35 Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated WO 2014/000035 PCT/AU2013/000690 2 element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Summary of the Invention 5 In a first broad aspect of the present invention there is provided a roller brake testing apparatus comprising: a base frame; at least one sub-frame, typically slidably mounted on the base frame, the sub frame supporting a first pair of rollers arranged to be driven by a motor; 10 a second pair of rollers arranged to be driven by a motor means for measuring or calculating the force or torque applied to turn the rollers to determine either the rolling resistance of the wheels or the braking force if the brakes are applied; the arrangement being such that the at least one sub-frame carrying the first pair of rollers may be moved towards and/or away from the second pair of rollers. 15 The movement of the sub-frame towards and/or away from the second pair of rollers allows the apparatus to be used with vehicles of differing axle length/wheel track width, enabling the same apparatus to be used with both on road vehicles and off road vehicles having relatively larger wheel track width. Typically, the diameter, of the rollers is from 110 mm. to 155mm. Most 20 preferably, the diameter of the rollers is at least 130mm and up to 155mm. By using relatively small diameter rollers, a number of advantages are provided over systems having larger diameter rollers, including the ability to make the unit operational without any civil works, allowing the unit to be mobile and simply deployed on top of the ground surface and accessed using ramps rather than being installed in ground. 25 However, it is also possible to provide suitable civil works and install the apparatus in ground. Typically the rollers are about 900mm to 1000mm long, most preferably about 920mm long. The central portion of each roller - about 800 -820mm long is typically spatter welded to provide a high friction test surface. 30 In a preferred embodiment, the second set of rollers is also mounted on a second sub-frame which is also slidably mounted on the base frame. In one preferred embodiment, the sub-frames are moved using hydraulic cylinders. Moveable covers may be provided which may prevent unintended movement of 35 the sub-frames as well as inhibit the ingress of debris into the apparatus.

WO 2014/000035 PCT/AU2013/000690 3 Typically, the apparatus will also include means for measuring the axle weight of the vehicle and shaker plates. The shaker plates will typically be mounted in a fixed position on the base frame, while allowing for movement in two perpendicular directions in the plane of the 5 shaker plate. Brief Description of the Drawings A specific embodiment of the present invention, will now be described, by way of example only, and with reference to the accompanying drawings in which: 10 Figure 1 shows a view of a roller brake tester with its rollers in a first (narrow track) position; Figure 2 shows the roller brake tester of Figure 1 with its rollers in a second (medium width track) position; and Figure 3 shows the roller brake tester of Figure I with its rollers in a third (wide 15 track) position. Detailed Description of a Preferred Embodiment Referring to the drawings, Figure 1 shows a schematic view of roller brake testing apparatus generally shown at 10. The apparatus is typically deployed on top of 20 a ground surface, rather than being installed in a recess in the ground. The apparatus includes a tubular steel external frame generally shown at 12. In the centre of the frame there is a hydraulic axle jack 14. On either side of the hydraulic axle jack 14 there are two separate sub-frames/carriages 16, 18 each of which house a roller assembly including a pair of rollers 20, 22. The frame 12 also houses 25 two wheel shaking assemblies 24. Each wheel shaking assembly includes a plate 26 and disposed underneath that plate are hydraulic and mechanical means (partly, shown at 28) for vibrating/shaking the plate in two perpendicular directions in the plane of the plate. The hydraulic jack 14 is used in conjunction with the shaker plates and may be raised to partially un 30 weight the axle which allows any mechanical play to be more easily generated and observed. The sub-frames 16, 18 are slidably mounted on the tubular steel frame 12 so that they can be moved in a horizontal plane in the direction of the arrows A-A towards or away from each other and the hydraulic axle jack. The rollers which are typically made 35 of steel are mounted in the sub-frames have a length of about 920mm and a diameter of about 130mm, although up to about 155mm is possible before it becomes necessary to WO 2014/000035 PCT/AU2013/000690 4 either mount the apparatus in a recess in the ground or provide impractically long approach ramps. The central part (about 824mm) is spatter coated to provide a high friction surface. Hydraulic cylinders, not shown, are provided to moved the sub-frames. 5 The control system, hydraulic motors and other equipment for operating the rollers, shaker plates, jack etc.. are mounted in a housing 100 on one side of the apparatus. With reference to Figure 1, it can be seen that there are two moveable covers in the form of plates, an inner cover 30 and an outer cover 32, between the sub-frame 16 10 and the housing 100. Similarly, there is an inner cover 34 and an outer cover 36 between the sub-frame 18 and the opposite side of the base frame 12. The apparatus can be adjusted to suit the track width of a vehicle (the measurement between the wheels on each side of the vehicle's axle, from the narrow track position shown in Figure 1, to the mid position shown in Figure 2 or the wide 15 position shown in Figure 3. The adjustment process is as follows. Starting with the narrow track shown in Figure 1 two of the inner moveable covers 30, 34, (one each side) are removed. The hydraulic cylinders are then activated to move the two sub-frames 16, 18 outwards away from the vehicle jack, to the position shown in Figure 2 where they abut the outer 20 covers 32, 36. The inner covers 30,34 are then placed in the gaps between the sub frames and the vehicle jack as shown in Figure 2. The covers maintain a relatively contiguous upper surface and inhibit debris such as that falling from vehicles from falling into the apparatus. To convert the apparatus to the wide track position shown in Figure 3 the outer 25 moveable covers 32, 36 are removed. The hydraulic cylinders are then activated to move the two sub-frames outwards away from the vehicle jack, to the position shown in Figure 3 where they abut the sides of the frame 12. The outer covers 32, 36 are then placed in the gaps between the sub-frames and the inner plates. In use, once the correct width has been set for the vehicle to be tested, the 30 vehicle is driven onto the roller assembly, one axle at a time. Relatively short ramps (not shown) may be used for this purpose. Each wheel on the axle sits between and is supported on a pair of rollers 20, 22. During a braking test, the rollers are arranged to turn the wheels, and the effort required to turn each wheel is measured. If the brakes are applied, this measures the braking force applied to the wheels. If the brakes are hot 35 applied, the wheel drag or rolling resistance is measured.

WO 2014/000035 PCT/AU2013/000690 5 As well as testing the vehicles braking system, the apparatus can also be used to test for mechanical play in the vehicle's wheel assembly, suspension and steering. To do this the vehicles wheels are driven onto the shaker plates 26 which are vibrated in two perpendicular horizontal axes. These forces simulate the forces that are 5 experienced as the vehicle travels on the roads, particularly unsealed roads. The operator of the apparatus can look out for mechanical play due 'to worn or loose components or the like. The hydraulic jack 14 is used in conjunction with the shaker plates and may be raised to partially un-weight the axle which allows any mechanical play to be more easily generated and observed. System can also be used to measure the 10 weight of each axle. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not 15 restrictive.

Claims (12)

1. A roller brake testing apparatus comprising: a base frame; at least one sub-frame, mounted on the base frame, the sub-frame supporting a 5 first pair of rollers arranged to be driven by a motor; a second pair of rollers arranged to be driven by a motor means for measuring or calculating the force or torque applied to turn the rollers to determine either the rolling resistance of the wheels or the braking force if the brakes are applied; 10 the arrangement being such that the at least one sub-frame carrying the first pair of rollers may be moved towards and/or away from the second pair of rollers.

2. A roller brake testing apparatus as claimed in claim 1 wherein the at least one sub-frame is slidably mounted on the base frame. 15

3. A roller brake testing apparatus as claimed in claim I or claim 2 wherein the diameter of the rollers is from 110 mm. to 155mm.

4. A roller brake testing apparatus as claimed in claim 3 wherein the diameter of 20 the rollers is from 130 mm. to 155mm.

5. A roller brake testing apparatus as claimed in any one of claims 1 to 4 wherein the rollers are from 900mm to 1000mm long. 25

6. A roller brake testing apparatus as claimed in claim 5 wherein the rollers are about 920mm long.

7. A roller brake testing apparatus as claimed in claim 5 or claim 6 wherein the central portion of each roller is spatter welded to provide a high friction test surface. 30

8. A roller brake testing apparatus as claimed in any one of claims 1 to 7 wherein the second set of rollers is mounted on a second sub-frame which is slidably mounted on the base frame. 35

9. A roller brake testing apparatus as claimed in claim 8 wherein the sub-frames are moved using hydraulic cylinders. WO 2014/000035 PCT/AU2013/000690 7

10. A roller brake testing apparatus as claimed in any one of claims wherein moveable covers are provided for covering part of the sub frame to prevent sliding movement of the sub-frames. 5

11. A roller brake testing apparatus as claimed in any one of claims 2 to 10 further including means for measuring the axle weight of the vehicle and shaker plates.

12. A roller brake testing apparatus as claimed in claim 11 wherein the shaker plates are mounted in a fixed position on the base frame, while allowing for movement in two 10 perpendicular directions in the plane of the shaker plate.