GB2194824A - Brake having a wear-indicating device - Google Patents

Brake having a wear-indicating device Download PDF

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Publication number
GB2194824A
GB2194824A GB08721088A GB8721088A GB2194824A GB 2194824 A GB2194824 A GB 2194824A GB 08721088 A GB08721088 A GB 08721088A GB 8721088 A GB8721088 A GB 8721088A GB 2194824 A GB2194824 A GB 2194824A
Authority
GB
United Kingdom
Prior art keywords
bushing
brake according
carrier plate
outer sleeve
brake
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08721088A
Other versions
GB2194824B (en
GB8721088D0 (en
Inventor
Detlef Badtke
Johannes Munch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Textar GmbH
Original Assignee
Textar GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Textar GmbH filed Critical Textar GmbH
Publication of GB8721088D0 publication Critical patent/GB8721088D0/en
Publication of GB2194824A publication Critical patent/GB2194824A/en
Application granted granted Critical
Publication of GB2194824B publication Critical patent/GB2194824B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D66/00—Arrangements for monitoring working conditions, e.g. wear, temperature
    • F16D66/02—Apparatus for indicating wear
    • F16D66/021—Apparatus for indicating wear using electrical detection or indication means
    • F16D66/022—Apparatus for indicating wear using electrical detection or indication means indicating that a lining is worn to minimum allowable thickness
    • F16D66/023—Apparatus for indicating wear using electrical detection or indication means indicating that a lining is worn to minimum allowable thickness directly sensing the position of braking members
    • F16D66/024—Sensors mounted on braking members adapted to contact the brake disc or drum, e.g. wire loops severed on contact

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)

Abstract

A device for indicating the wear limit of the friction lining in a brake shoe for disc brakes is formed from an outer sleeve (2) securely engaging, in use, with the bore (15) of a carrier plate and a closed bushing (3) which can be inserted into the sleeve (2) and which receives an electrical cable (5) and an inner sleeve (4) soldered or crimped to the free end of the electrical conductor (6). The outer sleeve (2) and the bushing (3) may have projecting collars (1, 11) which function as stops. The sleeves (2, 4) may be brass, and the bushing may be of PTFE. The device may be inserted into the carrier plate after assembly of the brake shoe so that it does not interfere with the assembly process and can be installed at an arbitrary location on the carrier plate. A longitudinal slot(s) may be provided on the outer sleeve to facilitate securement in the bore. <IMAGE>

Description

SPECIFICATION Brake having a wear-indicating device The invention relates to a device for indicating the wear limit of the brake lining of a brake shoe for disc brakes of motor vehicles, especially partially lined disc brakes, in which a sensor device having an electrical conductor can be inserted securely into a bore in the carrier plate of the friction lining.
Fixing of the electrical warning conductor in a bore of the brake shoe can be carried out in various ways. In some cases the installation site for the warning conductor on the brake shoe is determined by the fact that the part of the carrier plate where the warning conductor is to be installed is kept free from the friction lining. This requires either an enlargement of the carrier plate or a reduction in the effective friction lining surface. To avoid this, it has been proposed (DE-OS 27 51 674) to join the warning conductor together with the friction material during the pressing process and then to pass it through the carrier plate through an already present anchor bore for the friction lining. A warning conductor projecting from the carrier plate through an already present anchor bore for the friction lining.A warning conductor projecting from the carrier plate is a considerable obstacle for the pressing process and for further processing. DE-OS 29 06 710 describes a holding element for the sensor of the warning conductor fixed to a through bore of the carrier plate, with a blind bore provided at a point in the friction lining aligned with the through bore. In this case also the installation site for the warning conductor on the carrier plate has to be determined before completion of the brake shoe since the holding element can only be secured on the carrier plate while it is free from the friction lining. Also having a holding element projecting from the rear of the carrier plate is again a considerable obstacle in the pressing process for the further assembly of the brake shoe.
It is an object of the invention to produce an indicating device of the type mentioned above which can be secured on the brake shoe independently of its manufacturing steps, and is securely and firmly located.
The invention provides a brake for a motor vehicle comprising -a carrier plate including a bore, -a friction lining on the carrier plate, and -a device for indicating when the lining has worn by a predetermined amount, said device comprising i) an electrical cable having a conductor exposed at its end; ii) a bushing having a closed end enveloping the end of the conductor, and iii) a sleeve surrounding the bushing, the device being inserted in the bore such that, as the lining wears in use of the brake, the closed end of the bushing is worn away to enable the exposed end of the conductor to close an electric circuit and give a signal.
This kind of construction of the warning device allows a simple and reliable assembly of its parts. The shaping of the components ensures that these components can be assembled together easily and with relatively small pressure to form a structural unit, where the components are securely joined in their position both axially and radially. The indicating device can be inserted into a bore in the carrier plate which need not be bored until the brake shoe is completed. This allows flexibility with respect to the installation site of the indicating device on the rear of the brake shoe.
The rest of the design of the brake shoe does not affect the installation site for the indicating device, which can be selected according to requirements and can be changed at any time without the expense of modifying the structure of the carrier plate.
According to a further feature of the invention the outer sleeve may have a stop to limit its insertion into the carrier plate and the bushing a stop to limit its insertion into the outer sleeve. These stops may be in the form of collars.
According to a further feature of the invention the electrical conductor lying on the bushing can be surrounded by metal sleeve which is firmly connected to the conductor. The contact for the warning of a used friction lining is thus substantially increased in area and is more secure and more reliable.
The outer sleeve is preferably constructed with longitudinal slots to make radial compression possible. It is preferably of metal, e.g.
brass. This makes it possible for the inner components of the indicating device to be firmly braced against each other by the compression of the outer sleeve so that the entire indicating device can only be freed from the carrier plate of the brake shoe by using a great deal of force which leads to destruction of the contact.
According to a further feature of the invention the outer sleeve and the inner sleeve have on their inner and outer peripheries respectively sharp-edged toothed ribs or the like, preferably extending all round, which are directed so as to oppose extraction of the inner sleeve and of the preferably plastic bushing from the carrier plate. Thus the parts of the indicating device are held in force-fit connection with each other and are held together to form a fixed structural unit.
The length of the outer sleeve, measured from the inside of the collar, corresponds preferably to the thickness of the carrier plate of the brake shoe. This ensures that the fitting forces only have to be taken up by the carrier plate and not by the friction material, although the bore for the indicating device penetrates somewhat into the friction lining in the form of a blind hoie. This improves the secure fitting of the indicating device in the bore of the carrier plate.
The indicating device of the invention can be operated in such a way that the bushing, electrically conductive inner sleeve and cable form a ready-assembled structural unit, whereby this structural unit is not inserted into the outer sleeve, which is located in the carrier plate, until the indicating device is installed into the brake shoe. Alternatively, the outer sleeve, bushing, inner sleeve and cable can all be assembled previously to form a ready-assembled structural unit which is introduced as such into the bore of the carrier plate. In both cases a firm, water-tight and corrosion-proof seat for the indicating device in the brake shoe is arrived.
One embodiment of the indicating device of the invention will be described below with reference to the accompanying drawing.
Fig. 1 shows a cutaway view of an embodiment of the indicating device of the invention; and Fig.2 shows the arrangement of the indicating device of the invention in a brake shoe.
The indicating device 1 comprises four main parts, an outer sleeve 2, a bushing 3, an inner sleeve 4 and an electrical cable 5 with an exposed portion 6 of the electrical conductor, e.g. of a copper stranded wire.
The outer sleeve 2 is provided with one or more longitudinal slots 8 and is preferably made of metal, e.g. brass. The outer sleeve 2 has sharp-edged toothed ribs 9 on its inner surface which may extend all round, and which are directed so as to oppose removal of the indicating device. At one end the outer sleeve 9 has a projecting collar 10 used as a stop.
The bushing 3 is closed at the end 3a facing the friction lining and is formed from a temperature-resistant electrically insulating material (such as PTFE) and has on the part opposite the closed end 3a a collar 11 extending all around in projecting manner, which is used as a stop for the outer sleeve 2 into- which it can be inserted.
The inner sleeve 4 comprises electrically conductive material, e.g. brass, and is firmly connected to the free part 6 of the electrical cable 5, which may be done by soldering or crimping with the copper stranded wire 6 of the cable 5. This inner sleeve 4 also has on the outer periphery a sharp toothing 12 which may extend all round it and is directed so as to oppose withdrawai of the indicating device 1. Through the firm connection of the inner sleeve 4 to the free conductor part 6, the cable 5 inside the indicating device 1 is also fixed in the axial direction.
Components 2, 3, 4 and 5 can be easily assembled with relatively light pressure. They are braced radially against each other when pressed into the bore 15 of the carrier plate 14 having the friction lining 16, so that a fixed and reliable seat for the indicating device 1 in the bore of the carrier plate 14 is guaranteed. The radial pressing is effected by means of the slotted outer sleeve 2 with the teeth 9 and 12 engaging immovably into the rubber or synthetic bushing 3 from the outer and inner sides.
Operation of the brake wears down the brake lining and,near the end of the life of the lining, the closed end 3a of the bushing 3 also. Finally the material of the bushing is worn away and electrical contact is made between the disc and the cable, which operates the warning circuit to show that the lining must be replaced.
To assemble a brake shoe with the indicating device 1, first of all a blind hole 15 is bored in the completed brake shoe from the side of the carrier plate 14 remote from the friction lining 16, the bore also extending some way into the friction lining 16, and to such a depth that the indicating device can be inserted without touching the bottom of the bore. The length 2a of the outer sleeve 2, measured from the inside of the collar 10, is preferably equal to the thickness of the carrier plate 14. In this way the clamping forces of the outer sleeve 21 driven into the bore 15 are taken up only by the steel carrier plate 14, and the friction lining 16 is not touched by it.
The blind hole 15 can be made at any point in the rear of the carrier plate so that there is freedom of choice of the installation site of the indicating device depending on the brake assembly details.
The production and insertion of ;the indicating device can be carried out in different ways. One possibility is to provide the indicating device 1 complete and ready-made, with the parts 2, 3, 4 and 5 forming a self-contained structural unit, which is pressed as a whole into the bore of the carrier plate of the brake shoe. Another possibility is to insert the outer sleeve 2 into the bore 15 first, whereupon the pre-assembled parts 3, 4 and 5 are pressed into the outer sleeve 2 lying in the carrier plate 14 to form a structural unit. In each case a reliable, fixed and water-tight seat for the indicating device in the carrier plate of the brake shoe is achieved.

Claims (15)

1. A brake for a motor vehicle comprising -a carrier plate including a bore, -a friction lining on the carrier plate, and -a device for indicating when the lining has worn by a predetermined amount, said device comprising i) an electrical cable having a conductor exposed at its end; ii) a bushing having a closed end enveloping the end of the conductor, and iii) a sleeve surrounding the bushing, the device being held in the bore such that, as the lining wears in use of the brake, the closed end of the bushing is worn away to enable the exposed end of the conductor to close an electric circuit and give a signal.
2. A brake according to claim 1, wherein the outer sleeve and the bushing are provided at their ends remote from the closed end of the bushing with projecting stops which abut against the carrier plate -and the outer sleeve respectively.
3. A brake according to claim 2, wherein the stops are in the form of collars.
4. A brake according to claim 3, wherein the length of the outer sleeve, measured from the inside of the collar, corresponds to the thickness of the carrier plate.
5. A brake according to any preceding claim, wherein the exposed end of the conductor is surrounded by an inner sleeve of electrically conductive material firmly connected to it.
6. A brake according to claim 5, wherein the connection is made by soldering.
7. A brake according to claim 5, wherein the connection is made by crimping.
8. A brake according to any of claims 5 to 7, wherein the outer and inner sleeves are provided on their inner and outer peripheries respectively with sharp-edged toothed ribs which are directed so as to oppose withdrawal of the inner sleeve and the bushing from the carrier plate and together engage into the intermediate bushing.
9. A brake according to claim 8, wherein the ribs extend all round the peripheries of the inner and oxter sleeves.
10. A brake according to any of claims 5 to 9, wherein the bushing, inner sleeve and cable form a ready-assembled structural unit.
11. A brake according to any of claims 5 to 9, wherein the outer sleeve, bushing, inner sleeve and cable form a ready-assembled structural unit.
12. A brake according to any preceding claim, wherein the outer sleeve has longitudinal slots for radial compression.
13. A brake according to any preceding claim, wherein the outer sleeve is made of metal.
14. A brake according to claim 13, wherein the outer sleeve is made of brass.
15. A brake substantially as described herein with reference to the accompanying drawings
GB8721088A 1986-09-09 1987-09-08 Brake having a wear-indicating device Expired - Fee Related GB2194824B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19868624060 DE8624060U1 (en) 1986-09-09 1986-09-09 Indicator device for the wear limit of the friction lining of a brake shoe

Publications (3)

Publication Number Publication Date
GB8721088D0 GB8721088D0 (en) 1987-10-14
GB2194824A true GB2194824A (en) 1988-03-16
GB2194824B GB2194824B (en) 1990-03-28

Family

ID=6798122

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8721088A Expired - Fee Related GB2194824B (en) 1986-09-09 1987-09-08 Brake having a wear-indicating device

Country Status (8)

Country Link
BE (1) BE1001162A4 (en)
DE (1) DE8624060U1 (en)
ES (1) ES2007711A6 (en)
FR (1) FR2603677B3 (en)
GB (1) GB2194824B (en)
IT (1) IT211800Z2 (en)
NL (1) NL8702004A (en)
SE (1) SE500571C2 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2241543A (en) * 1990-03-02 1991-09-04 Perrot Bremse Gmbh Deutsche A brake-lining wear indicating device
US5151681A (en) * 1989-08-25 1992-09-29 General Motors France Brake wear indicating device
GB2255145A (en) * 1991-04-22 1992-10-28 Gen Motors France Brake wear indicating device.
US5168260A (en) * 1990-05-31 1992-12-01 Bendix Europe Services Techniques Wear indicator for a friction lining
EP0546759A1 (en) * 1991-12-12 1993-06-16 Sumitomo Wiring Systems, Ltd. A wear-detection probe for a brake lining material
FR2697066A1 (en) * 1992-10-20 1994-04-22 Cablage Cie Francaise Brake pad wear indicator for motor vehicle.
US5307673A (en) * 1991-12-13 1994-05-03 Sumitomo Wiring Systems, Ltd. Wear-detection probe for a brake lining material
US5501828A (en) * 1992-07-08 1996-03-26 Sumitomo Wiring Systems, Ltd. Method for producing a wear-detection probe for a brake lining material
EP1098103A1 (en) * 1999-11-05 2001-05-09 I.C.P. S.r.l. Wear detector for a vehicle braking member
US6725977B2 (en) * 2001-07-11 2004-04-27 Sumitomo Wiring Systems, Ltd. Wear-detecting probe and a braking element provided therewith

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1360768A (en) * 1972-05-05 1974-07-24 Dba Sa Wear detecting device for friction linings
GB1445539A (en) * 1974-04-26 1976-08-11 Toyota Jidosha Kogyo Kk Akebon Device for warning of excessive wear on a brake lining

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7319150U (en) * 1973-09-06 Pampus Kg Flanged socket with a cable loop for use as a wear indicator in brake linings
FR1457672A (en) * 1965-09-23 1966-01-24 Renault Brake pad with wear switch
FR2266056A1 (en) * 1974-03-25 1975-10-24 Cama Michel Wear detector for disc brakes - has insulating probe cover worn away to close signal circuit
DE2909247A1 (en) * 1979-03-09 1980-09-11 Don Deutschland Gmbh WEAR INDICATOR FOR BRAKE PADS
FR2504226A1 (en) * 1981-04-21 1982-10-22 Valeo Wear detector for mounting in brake shoe linings - comprising looped conductor wires mounted in heat resistant sleeves and moulded holders
DE8419083U1 (en) * 1984-06-26 1985-10-24 Textar Gmbh, 5090 Leverkusen Display device for friction linings of disc brakes for motor vehicles

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1360768A (en) * 1972-05-05 1974-07-24 Dba Sa Wear detecting device for friction linings
GB1445539A (en) * 1974-04-26 1976-08-11 Toyota Jidosha Kogyo Kk Akebon Device for warning of excessive wear on a brake lining

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5151681A (en) * 1989-08-25 1992-09-29 General Motors France Brake wear indicating device
GB2241543B (en) * 1990-03-02 1993-09-08 Perrot Bremse Gmbh Deutsche A brake-lining wear indicating device
GB2241543A (en) * 1990-03-02 1991-09-04 Perrot Bremse Gmbh Deutsche A brake-lining wear indicating device
US5168260A (en) * 1990-05-31 1992-12-01 Bendix Europe Services Techniques Wear indicator for a friction lining
GB2255145A (en) * 1991-04-22 1992-10-28 Gen Motors France Brake wear indicating device.
US5347858A (en) * 1991-12-12 1994-09-20 Sumitomo Wiring Systems, Ltd. Wear-detection probe for a brake lining material
EP0546759A1 (en) * 1991-12-12 1993-06-16 Sumitomo Wiring Systems, Ltd. A wear-detection probe for a brake lining material
US5307673A (en) * 1991-12-13 1994-05-03 Sumitomo Wiring Systems, Ltd. Wear-detection probe for a brake lining material
US5501828A (en) * 1992-07-08 1996-03-26 Sumitomo Wiring Systems, Ltd. Method for producing a wear-detection probe for a brake lining material
FR2697066A1 (en) * 1992-10-20 1994-04-22 Cablage Cie Francaise Brake pad wear indicator for motor vehicle.
EP0594514A1 (en) * 1992-10-20 1994-04-27 Compagnie Francaise De Cablage Automotive brake lining wear detector
EP1098103A1 (en) * 1999-11-05 2001-05-09 I.C.P. S.r.l. Wear detector for a vehicle braking member
US6725977B2 (en) * 2001-07-11 2004-04-27 Sumitomo Wiring Systems, Ltd. Wear-detecting probe and a braking element provided therewith

Also Published As

Publication number Publication date
ES2007711A6 (en) 1989-07-01
BE1001162A4 (en) 1989-08-01
FR2603677B3 (en) 1988-11-10
FR2603677A3 (en) 1988-03-11
SE8703498D0 (en) 1987-09-09
IT8722248V0 (en) 1987-09-02
GB2194824B (en) 1990-03-28
IT211800Z2 (en) 1989-05-25
SE8703498L (en) 1988-03-10
DE8624060U1 (en) 1988-01-14
SE500571C2 (en) 1994-07-18
GB8721088D0 (en) 1987-10-14
NL8702004A (en) 1988-04-05

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940908