EP0114821A1

EP0114821A1 - Modified brake shoe pads

Info

Publication number: EP0114821A1
Application number: EP19830900168
Authority: EP
Inventors: Shawky Shafeek Michael
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-07-14
Filing date: 1982-12-31
Publication date: 1984-08-08
Also published as: WO1984000407A1; WO1984000406A1; EP0113722A1

Abstract

Des coussinets de sabot pour tout type de véhicules de transport sont modifiés en faisant travailler le coussinet lui-même (1) comme conducteur pour transférer un signal électrique lors du contact avec la roue, le tambour ou le disque. Le signal produit est utilisé comme avertissement en cas de blocage du frein ou en cas d'usure du coussinet. La modification est exécutée simplement en plaçant des fils conducteurs mous (3) et (4) ou des bandes métalliques molles conductrices (5) et (6) dans le coussinet ou sur celui-ci sans toucher le sabot métallique (2). Le fil (3) ou métal (5) long produit un signal en touchant la roue tandis que le fil (4) ou métal (6) court crée un signal indiquant le niveau d'usure, également en touchant la roue. Les signaux provenant de (3) et (5) sont synchronisés avec le mouvement de freinage de manière à annuler ces signaux pendant le freinage normal afin d'éviter tout déclenchement incorrect d'un signal d'avertissement.Hoof pads for all types of transport vehicles are modified by making the pad itself (1) work as a conductor for transferring an electrical signal upon contact with the wheel, drum or disc. The signal produced is used as a warning in the event of a brake lock or if the pad is worn. The modification is carried out simply by placing soft conductive wires (3) and (4) or soft conductive metal bands (5) and (6) in or on the pad without touching the metal shoe (2). The long wire (3) or metal (5) produces a signal by touching the wheel while the short wire (4) or metal (6) creates a signal indicating the level of wear, also by touching the wheel. The signals from (3) and (5) are synchronized with the braking movement so as to cancel these signals during normal braking in order to avoid incorrect triggering of a warning signal.

Description

MODIFIED BRAKE SHOE PADS

FIELD OF INVENTION

This invention relates to the brake shoe pads (non-metallic) system applied in all fields of automotives, viz: motor cycle, passenger motor vehicle, load carrying trucks, railway trucks and aeroplanes. Utilising a simple modification within the brake shoes, said invention has the advantage of warning a driver in the following cases:-

1- Brake shoe is touching the wheel, disc or wheel drum and locking. 2- Indication of how low the brake shoe has been worn out.

PRIOR ART

Apart from the old conventional system for giving a light warning when the hand brake is applied, the inventor of this invention has cited a different type of brake shoe low wearing level as old as 1976 in Renault 16 TS passenger car. However all the above prior art is usually unsatisfactory due to many reasons including:-

1- The hand brake signal indicator commonly fails due to the burning out of indicator light bulb, or ryst or damage at the hand lever contact switch, or simply a slight displacement of the hand lever switch which will give an indication that the brake is released while it is still touching the drum s).

2- The hand brake signal indicator works only on 2 wheels and not wheels and if the other two brake shoes are touching the drums due to poor adjustment or maintenance, said indicator would not indicate this action.

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GV ^ Wl/ 3- The brake shoe wear warning device is usually not a very accurate measure of the thickness of the actual shoes themselves and once again, it is usually an indication for two wheels only.

4- Large trucks with many wheels simply have no warning system particularly the trailers of semi-trailer vehicles.

5- All railway wagons and trucks have no indication of a brake shoe locking or level of wearing, and despite its common occurrence,said locking or level of wearing is usually relayed following manual inspection only or in an even more unsatisfactory method, whereby the guard on the last railway truck signals the locomotive driver when and if he notices smoke caused by brake shoe(s) locking . In the case of strong wind or rain, it is very difficult to observe or notice any smoke.

PROBLEMS REQUIRING THIS INVENTION It has been found in practice that in many cases, such as a motor vehicle's braking shoes locking into a braking position , the resulting friction causes a build up of extreme heat causing an increase in petrol consumption and consequently causes quicker wear in tyres and also in many cases may result in the ignition of the brake fluid followed by ignition of tyres and possibly the entire vehicle.

In the case of a caravan being towed, semi-trailer and long trucks, said braking shoes locking into a braking position severely affects the balance of the rear part of the vehicle particularly when a heavy load is being transported, which in effect greatly reduces the safety of the said trucks and trailers on the road and accidents may occur. - 3 - Usually in large trucks, such brake locking is not felt by the driver due to the relatively great power of the engine of the Vehicle.

In the case of passenger or goods trains, beside the risk of train carriage fire and possibly injury and/or death in the case of brake locking, derailments or severe structural damage to the railway trucks may occur.

Finally,when the brake shoe is totally consumed without a warning, this is usually associated with severe structural damage caused by the friction between the wheel drum and the brake shoe metal plate which usually results in costly machining of the wheel drum or complete replacement and a consequent huge loss in money and time.

SUMMARY OF THE INVENTION To overcome the problems referred to above, the invention described herein, utilises the brake shoe lining itself to give the warning signals In the case of a locking or jamming position and in the case of wear of the shoe pad itself. This is carried out by using two different lengths of any size or shape of soft conducting material or alloy such as aluminium, copper, lead, or graphite.

Said two conductors are implanted in or alongside the shoe pad itself in any location, although the middle of the shoe is preferred, in the form of a wire or thin metal foil so as to be used as electrical conductors when touching the disc,..wheel or wheel drums. DESCRIPTION OF THE INVENTION

Figure 1 is a schematic perspective view of a motor vehicle brake shoe pad with the attached wire or foil sensors in ppsition. Figure 2 is a schematic illustration of a railway train brake shoe pad with the attached wire or foil sensors in position.

Figure 3 represents a schematic perspective view of a car braking system in the pad wear position A and in the case of locking position B. Figure - illustrates the braking system for a railway and shows the pad wear position A and locking position B.

Figure 5 represents the logic flow of the system. The brake shoe pads 1 shown in Figures 1 and 2 are usually attached to the metal brake shoes 2 by riveting or special adhesive. The sensors are in the form of wires 3 and of any form or shape, separated or coaxial shape and placed in a central place or alongside the pad; said sensors may also be made In the form of metal strips 5 and 6 adhered to the pad. The sensors 3,4,5, and 6 are manufactured from any soft but conductive material so as not to mark any wheels, discs or wheel drums.

The long wire 3 or strip 5 will touch the brake drum or the wheel as in Figure 3 (B) and Figure (B) and due to the non existence of any rust or particles in these areas, said sensors 3 or 5 will cause an electrical short circuit, but with a simple electric switch with the braking light system, a cancellation signal is given so as to prevent the appearance of any false warning lights or sound.

V vnto The same principle is applied in the case of wear in braking pad reaching a low level, hereby the sensor wire or metal 6 will touch the wheel, disc or the wheel drum, short-circuiting the electric power and giving a direct signal to the driver. This signal is indepen- dent from said brake signaling synchronisation and appears when braking as well as when a locking in the brake occurs, and in such a case, the driver receives two independent signals for brake locking and for brake shoe pad wear.

Wires connected from the brake pad(s) under the car, trailer, _, train or aeroplane, are usually made of heavy duty type to withstand any movement or heat.

The above description of the invention together with the accompanying Figures clearly indicates that the brake warning system is a simple and cheap method to produce at the same time as the manufacturing of the brake shoe and offers a unique and accurate method of giving a warning when brake shoes lock or brake shoe pads reach the low wear point.

The Main -Advantages In This Invention Are:- 1- Road, railway and aviation safety increases. 2- Less damage in all types of vehicles and railway carriages and an increase in productivity due to less time being lost with repairs.

3- Less fuel, tyres and brake shoe pads consumption.

Claims

- 6 - The Claims Defining The Invention Are As Follows:-

1. A brake warning device with dual purpose to warn the driver of motor vehicle, railway train, motor cycle or aeroplane when the non- metallic brake shoe pad is locking with the wheel, disc or wheel drum, and to warn said driver when the brake .-shoe pad reaches a low wear point and requires replacement. Said brake warning device comprises sensors which are implanted in the brake shoe pads to give an instant and reliable warning signal; and simple electric circuit so as to relay to the driver the warning signals.

2. A device as claimed in claim 1 wherein said brake shoe pad sensors are made from any material which is soft and highly conducti to electricity.

3. A device as claimed in claim 1 wherein said brake shoe pad sensors are implanted in or adhered to the said shoe pad itself in any position but without touching the metal shoe itself. Said positioning is due to the fact that when braking is applied, usually the entire pad touches the wheel, disc- , or wheel drum and closes the electric circuit.

4. A device as claimed in claim 1 wherein said brake shoe pad sensors are made of any shape or size of wires of two different lengths. The wires are attached together or separated and the long wire reaches the top surface of said brake pad to allow it to touch the surface of the wheel, disc or wheel drum closing the electric circuit and giving a warning to the driver that the brake is in a locking position. The short wire will work spontaneously as an indicator of the lower limit of pad wear and when touching the wheel, disc, or wheel drum it automatically gives a signal.

- 7 - 5. A device as claimed in claim wherein said brake shoe pad sensors may also be made of two metal strips or foils attached to the side of said brake shoe pad or produced inside the pad itself representing a line of cross section of any direction in the pad.

6. A device as claimed in claim 1 and wherein said low level wear sensor for brake shoe pad could be designed to be more than one sensor for the indication of different levels of low wear of the said pad; for example, one sensor for low wear level with a wire attached to a non continuous warning sound and light and the other is for the very low level of said pad wear with a continuous warning.

7. A device as claimed in claim 1 wherein said electric switch is to synchronise with the normal rear braking light so as to spontaneously cancel the brake locking warning light when the driver applies the brake.

8. A device as claimed in claims 1, 3, 4, 5 and 6 is produced with attached strong wires for shock and heat resistance. Said wires are easily connected to the main circuit by a simple plugging technique so as to avoid cutting or any soldering.

9. Brake locking and pad wear warning device for all types of brakes, substantially as herein described with reference to accompanying drawings.