AU2003200952A1 - Roller Positioning in Brake Testing Apparatus - Google Patents

Description

P/01/009 2a51 Regulation 3.2

AUSTRALIA

Patents Act 1990 TRUE COPY COMPLETE SPECIFICATION STANDARD

PATENT

I certify that the following pages are a true and correct copy of the description and claims of the original complete specification in respect of an invention entitled Roller Positioning in Brake Testing Apparatus Nam e of A Richard.. GARTNE Signature Applicant's Patent Attorney ROLLER POSTIONING IN BRAKE TESTING APPARATUS FIELD OF THE INVENTION THIS INVENTION relates to the testing of vehicles and is more specifically concerned with apparatus for determining the braking performance of individual wheels of a vehicle.

STATE OF THE ART Testing of a vehicle's brakes first takes place when the vehicle is manufactured prior to it being distributed to sales outlets. Further testing of the brakes on an annual basis may then be called for by legislation when the vehicle is more than .a certain age. Such legislation usually sets performance criteria which must be complied with as a condition of the annual re-registration of the vehicle.

Garages are often equipped with test bays containing apparatus for testing the brakes of a vehicle. The vehicle is driven at a slow speed to a position at which each of its wheels is resting on a separate test plate and it is then sharply braked. The momentum of the vehicle during braking is transmitted as horizontal thrusts which are applied by way of the vehicle's wheels to the individual test plates. Sensing and recording cells associated with each of the plates measures the thrust exerted on the plate during braking and provide data from which the braking efficiency of the vehicle's wheels can be measured to check that it complies with the parameters required by legislation. It is normal practice to arrange for the test plates to be individually supported by sets of rollers spaced beneath them. These rollers are mounted on horizontal surfaces such as rails or tracks on the floor of a concrete test bed, and this allows the thrusts exerted on the test plates during braking to be measured by the cells.

It will be appreciated that garages inevitably accumulate grit and dirt and this can easily find its way beneath the undersides of the rollers over a period of time. This may then impair the correct measurement of the braking efficiency by the cells, through obstructing movement of the rollers.' It is therefore necessary for such apparatus to be stripped down and cleaned at regular intervals. Re-calibration is also necessary to ensure that aging of the operating components .of the test bay does not impair its performance. Such maintenance is normally undertaking under a maintenance contract and this involves a further financial burden on the garage which has paid for the installation of the apparatus.

2 An object of this invention is to provide apparatus for testing the braking performance of a vehicle.

THE INVENTION In accordance with the present invention, apparatus for testing a vehicle's brakes is provided with test plates for supporting respective wheels of the vehicle and which each has an associated horizontal-thrust measuring cell connected to means for computing the braking performance of the associated vehicle wheel from the braking thrust exerted on the plate during braking of the vehicle, each plate having its underside resting on sets of rolling surfaces which are rigidly supported so that the undersides of the rolling surfaces are spaced above the surfaces beneath them. The rolling surfaces preferably comprise the upper peripheries of respective rollers.

ADVANTAGES OF THE INVENTION As the undersides of the rollers do not engage a track in order to support the weight of the plates, the risk of grit and dirt lodging between the rollers and a track and thereby impairing the correct operation of the apparatus, is greatly reduced or avoided altogether.

PREFERRED FEATURES OF THE INVENTION In the preferred arrangement each roller is supported above a floor of a steel channel by mounts rigidly attached to it. The channel suitably rests on a concrete foundation and is levelled so that it is horizontal, during installation of the test bay. A plastics loadsupporting material may be located between the underside of the channel and a concrete foundation during installation of the test bay and, while the material is soft, the channer is adjusted so that its underside is horizontal. The plastics material is then allowed to harden.

Each test plate is conveniently mounted so that it spans across the upper part of the cavity of the channel with its longitudinal edges of that plate extending close to the sides of the channel. The cells and other components of the apparatus which are necessary to measure the braking momentum of the test plates may then be mounted inside the cavity of the channel.

It is preferred for sloping side strips to be provided along each outer side of the channel so that the tyres of a vehicle can be driven up or down the sloping side strips in order for the vehicle to be driven on or off the apparatus. Preferably these sloping side strips are integrally formed with the channel plate as a unitary assembly produced by rolling a strip of mild steel or other suitable material.

INTRODUCTION TO THE DRAWINGS The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which:- IN THE DRAWINGS FIGURE 1 is a side view of apparatus for testing the braking performance of a vehicle's wheels and shows the positions of sets of rollers in phantom outline; FIGURE 2 is a plan view of the apparatus of figure 1; FIGURE 3 is a cross section through part of the apparatus on an enlarged scale and is taken on the line and in the direction indicated by the arrows i- I of figure 2; and, FIGURE 4 is a plan view of a portion of a part of the apparatus lying beneath a test plate the test plate being shown in phantom outline to expose the positions and mounting of the rollers more clearly and way in which a test cell is connected to the test plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT Figures 1 and 2 show apparatus for testing the brakes of a vehicle and which is mounted on a concrete slab 1 providing a foundation having a level, if not smooth upper surface 2, A thin layer 3 of hardenable plasticised material shown in Figure 3 is placed on the surface 2 at the position at which the apparatus is to be mounted, and a rolled, mild steel channel plate 4, having a downwardly-sloping side strips is positioned with its underside on the layer 3 and is adjusted so that it is accurately horizontal in length and in width. The plasticised material 3 hardens fairly quickly to hold the channel plate in this position. A second channel plate 4 is similarly mounted alongside and spaced from the first channel plate as shown in figure 2 so that each lies beneath the positions of the tyres of a vehicle (not shown) to be brake tested.

A pair of rectangular test plates 9 are mounted so that they span almost the whole way across the upper interior cavity of the channel as shown in figures 3 and 4. Fixed metal sheets 7 and 8 close the upper part of the cavity of the channel beyond and between the test plates 9. The two parallel sides of the plates 9 are turned down as shown at 11 in figure 3.

As shown in figure 4, each of the test plates 9 has attached rigidly to its underside a Cshaped member 21 having side arms 22 through which passes a bolt 25. The bolt also passes through a threaded aperture 2 3 in a stout bar 24 which is connected to a sensing cell 20. The head of the bolt is accessible on top of the test plate 9 and it can be adjusted to alter the position of the angle bar 24 during calibration of the cell 20. A pillar 26 is welded to the floor of the channel 4. The load cell 20 has an opening 27 through which the bar 24 is a tight sliding fit. The bar 24 has a head 28, and the cell 20 extends horizontally between the head 28 and the pillar 26.

As shown in figures 3 and 4, the underside of the plate 9 is supported at each side by a set of five spaced rollers 10. These have respective shafts 13 which are carried by mounts in the form of upright steel lugs 14 located in pairs with one lug of each pair 2 0 being positioned on each side of a respective roller. The lugs 14 are welded at their bases to the floor of the cavity of the channel 4 so that the undersides of the rollers 10 are spaced from the floor as shown in figure 3. The rollers 10 thus support the weight of the plate 9 and are able to move arcuately through a very small angle during braking when the plate thrust is being transmitted horizontally through the angle bar 24 to the cell flexible rubber sealing ribbon (not shown) closes the elongated gaps between the sloping side strips and the foundation 1 and also the narrow gaps left between the plates 7, 8 and the channel 4. These seals are flexible so they do not impair the operation of the apparatus in any way and simply restrict the entry of dirt and grit into the cavity of the channel plate 4.

As is apparent from figure 4, the steel channel plate 4 provides the sloping side strips as well as an elongated rectangular cavity which contains the rollers 10, test cells 20 and associated equipment, and the lugs 14 which support the weight of the rollers and the test plate 9. The channel plate 4 and side strips 5 are suitably, although not essentially, are fabricated by a roll-forming process.

OPERATION OF THE PREFERRED

EMBODIMENT

A vehicle (not shown) which is to have its brakes tested is driven slowly onto the apparatus from one end until its front wheels its rear wheels locate on respective test plates 9. The vehicle's brakes are then applied and the momentum of braking of the vehicle is imparted as a horizontal thrust exerted on the test plates 9 in the direction of travel of the vehicle. These thrusts are transmitted through the angle bars 24 to the test cells 20. This enables the braking efficiency of each wheel of the vehicle to be ascertained, and for an operator to see at once from a display dial whether any of the wheels has an impaired braking efficiency, or whether the rear wheels have a braking efficiency which deviates from the braking efficiency of the front wheels more than a permitted amount. These results can be indicated immediately by the dial positioned above the test bay, so that the owner of the vehicle can see immediately what adjustments are necessary to enable his vehicle to comply with the statutory requirements.

As shown in Figures 3 and 4, the channel plate 4 is provided with four internally threaded nuts 31 welded to it and registering internally with respective holes in the plate 4. Bolts are screwed through the respective nuts 31 and can be turned to adjust the heights of the corresponding corner portions of the channel plate. 4 above the layer 3 before it hardens. This provides a simple way of horizontally levelling the channel plate 4 during the installation of the apparatus.

Claims (4)

1. Apparatus for testing a vehicle's brakes, comprising test plates for supporting respective wheels of the vehicle and which each has an associated horizontal thrusts measuring cell connected to means for computing the braking performance of the associated vehicle wheel from the braking thrust exerted on the plate during braking of the vehicle, each plate having its underside resting on sets of rolling surfaces which are rigidly supported above a foundation so that the undersides of the rollers are spaced above the surfaces beneath them.

2. Apparatus as claimed in claim 1, in which the rolling surfaces are provided by rollers.

3. Apparatus as claimed in claim 1 or claim 2, in which the rolling surfaces are supported by mounts rigidly attached to the floor of a channel providing a cavity containing the rollers, the mounts and the thrust-measuring cells the test plates spanning between the upper portions of the parallel sides of the channel.

154. Apparatus as claimed in claim 3, in which the channel is formed along the upper edge-portion of each of its parallel sides with a downwardly sloping strip to assist the tyres of a vehicle to drive on and off the test plates. Apparatus as claimed in claim 3 or claim 4, in which the mounts comprise steel lugs welded to the floor of the channel and arranged one each side of each of the rolling surfaces. 6. Apparatus as claimed in claim 1, arranged and adapted to operate substantially as described with reference to the accompanying drawings. Dated this 8thday of March 2003. Michael Gartner By:..Patent A....oney Patent Attorne