GB2149034A - Brake pad wear indicator - Google Patents

Brake pad wear indicator Download PDF

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Publication number
GB2149034A
GB2149034A GB08330236A GB8330236A GB2149034A GB 2149034 A GB2149034 A GB 2149034A GB 08330236 A GB08330236 A GB 08330236A GB 8330236 A GB8330236 A GB 8330236A GB 2149034 A GB2149034 A GB 2149034A
Authority
GB
United Kingdom
Prior art keywords
brake pad
brake
wear indicator
wire
sleeved
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.)
Withdrawn
Application number
GB08330236A
Other versions
GB8330236D0 (en
Inventor
Joeseph Barrett
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.)
Hazel Grove Jig & Tool Co Limi
Original Assignee
Hazel Grove Jig & Tool Co Limi
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 Hazel Grove Jig & Tool Co Limi filed Critical Hazel Grove Jig & Tool Co Limi
Priority to GB08330236A priority Critical patent/GB2149034A/en
Publication of GB8330236D0 publication Critical patent/GB8330236D0/en
Publication of GB2149034A publication Critical patent/GB2149034A/en
Withdrawn legal-status Critical Current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 metal brake pad 3 (the term 'brake pad' encompassing brake shoes) has a wear indicator 7 with a length of sleeved wire 9 adapted to be connected at one end to the high side of a power supply via a wear indicator device 13 and the other end of which is intended in use to be secured in the brake pad 3 at a point thereof corresponding to the brake pad being worn away. An insulating cap 11 is secured to the end of the sleeved wire 9 and is intend to be secured in the brake pad 3 to prevent the sleeved wire shorting through the metal brake pad and to facilitate securing the said end in the brake pad. The cap 11 may be of a plastics or rubber material-it may be bonded to wire 9 or integrally moulded thereon. <IMAGE>

Description

SPECIFICATION Improvements in or relating to brake pad wear indicators The present invention relates to a wear indicator for use in brake pads and, in particular, for use in metal brake pads.
In order to indicate when a brake pad has worn away to such an extent that is is necessary to replace it a wear indication is inserted in the brake pad. The wear indicator comprises a wire inserted into the brake pad near the backing place and connected via an indicator device to the high side of a power supply. As the brake pad wears down towards the backing plate the wire is eventually exposed and makes contact with the brake disc or hub. As this is earthed through the chassis the indicator circuit is closed and the indicator device turned on.
Conventional wear indicators comprise a length of sleeved wire having a connection terminal at one end to connect the wear indicator to the power supply. The other end of the sleeved wire is simply bonded into a hole drilled in the brake pad. It will be appreciated that the end of the sleeved wire bonded into the hole in the brake pad is left exposed and uninsulated. In the asbestos brake pads used to-date this does not present a problem because the asbestos itself is non-conducting.
However, as a result of the increased appreciation of the dangers associated with asbestos metal brake pads are being introduced to replace their asbestos counterparts. Clearly it is impossible to use conventional wear indicators in these new metal brake pads as the exposed end of the sleeved wire shorts through the brake pad to the brake disc or hub, thus indicating worn brake pads before any wearing of the brake pad has occured.
It is an object of the present invention to provide a wear indicator in which shorting to earth through the use of metal brake pads is eliminated.
According to the present invention there is provided a brake pad wear indicator for use with metal brake pads, comprising a length of sleeved wire adapted to be connected at one end to the high side of a power supply via a wear indicator device and the other end of which is intended in use to be secured in the brake pad at a point thereof corresponding to the brake pad being worn away, wherein an insulating cap is secured to the end of the sleeved wire intended to be secured in the brake pad to prevent the sleeved wire shorting through the metal brake pad and to facilitate securing the said end in the brake pad.
The insulating cap may be bonded onto the end of the sleeved wire to be secured in the brake pad or may be moulded onto the said end.
An embodiment of the present invention will not be described, by way of example, with reference to the accompanying drawing, which shows a disc brake arrangement and a brake pad wear indicator circuit comprising a wear indicator according to the present invention.
Referring to the accompanying drawing there is shown a disc brake arrangement 1 for a vehicle, comprising a brake disc 2 and two brake pads 3 and 4, each mounted on a respective backing plate 5 and 6. The disc brake arrangement 1 and its operation are conventional except that the brake pads are of metal.
Each brake pad 3, 4 is provided with a wear indicator, 7 and 8 respectively. Of these the wear indicator 7, associated with brake pad 3 is shown in detail and will now be described. The wear indicator 7 comprises a length of sleeved wire 9 having a connection terminal 10 at one end and insulating cap 11.
The insulated end of the wear indicator 7 is secured in a hole 1 2 in the brake pad 3, which hole 1 2 is located adjacent the backing plate 5. In this position the wear indicator is protected from the brake disc 2 until the brake pad 2 is worn right down to it. When this occurs the brake pad 3 is in need of replacement and this is indicated by an indicator device 1 3 located on the vehicle dashboard (not shown). When the brake disc 2 reaches the wear indicator 7 it strips of the insulation covering it, exposing the bare wire underneath. The brake disc 2 is earth through the vehicle chassis (not shown) and thus the circuit including the wear indicator device 1 3 is closed turning the wear indicator device on.
As stated hereinbefore the brake pads 3 and 4 are of metal and thus it is essential, if the wear indicator is to operate reliably, to ensure that it is insulated from the brake pad in which it is mounted. To this end the insulating cap 11 is provided on the end of the sleeved wire 9 to be mounted in the brake pad 3. The insulating cap 11 may be comprised of any insulating material, but prefera bly is comprised of a plastics material or rubber material which will fit on the sleeved wire 9 securely and bond in the hole 1 2 so as to prevent the wear indicator 1 from being pulled from the hole 1 2 in use. To this end the insulating cap 11 maybe bonded to the end of the sleeved wire 9 or may be integrally moulded thereon.
It will be appreciated that throughout this specification the use of the term "brake pad" is intended to encompass brake shoes.
1. A brake pad wear indicator for use with metal brake pads, comprising a length of sleeved wire adapted to be connected at one end to the high side of a power supply via a wear indicator device and the other end of which is intended in use to be secured in the
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to brake pad wear indicators The present invention relates to a wear indicator for use in brake pads and, in particular, for use in metal brake pads. In order to indicate when a brake pad has worn away to such an extent that is is necessary to replace it a wear indication is inserted in the brake pad. The wear indicator comprises a wire inserted into the brake pad near the backing place and connected via an indicator device to the high side of a power supply. As the brake pad wears down towards the backing plate the wire is eventually exposed and makes contact with the brake disc or hub. As this is earthed through the chassis the indicator circuit is closed and the indicator device turned on. Conventional wear indicators comprise a length of sleeved wire having a connection terminal at one end to connect the wear indicator to the power supply. The other end of the sleeved wire is simply bonded into a hole drilled in the brake pad. It will be appreciated that the end of the sleeved wire bonded into the hole in the brake pad is left exposed and uninsulated. In the asbestos brake pads used to-date this does not present a problem because the asbestos itself is non-conducting. However, as a result of the increased appreciation of the dangers associated with asbestos metal brake pads are being introduced to replace their asbestos counterparts. Clearly it is impossible to use conventional wear indicators in these new metal brake pads as the exposed end of the sleeved wire shorts through the brake pad to the brake disc or hub, thus indicating worn brake pads before any wearing of the brake pad has occured. It is an object of the present invention to provide a wear indicator in which shorting to earth through the use of metal brake pads is eliminated. According to the present invention there is provided a brake pad wear indicator for use with metal brake pads, comprising a length of sleeved wire adapted to be connected at one end to the high side of a power supply via a wear indicator device and the other end of which is intended in use to be secured in the brake pad at a point thereof corresponding to the brake pad being worn away, wherein an insulating cap is secured to the end of the sleeved wire intended to be secured in the brake pad to prevent the sleeved wire shorting through the metal brake pad and to facilitate securing the said end in the brake pad. The insulating cap may be bonded onto the end of the sleeved wire to be secured in the brake pad or may be moulded onto the said end. An embodiment of the present invention will not be described, by way of example, with reference to the accompanying drawing, which shows a disc brake arrangement and a brake pad wear indicator circuit comprising a wear indicator according to the present invention. Referring to the accompanying drawing there is shown a disc brake arrangement 1 for a vehicle, comprising a brake disc 2 and two brake pads 3 and 4, each mounted on a respective backing plate 5 and 6. The disc brake arrangement 1 and its operation are conventional except that the brake pads are of metal. Each brake pad 3, 4 is provided with a wear indicator, 7 and 8 respectively. Of these the wear indicator 7, associated with brake pad 3 is shown in detail and will now be described. The wear indicator 7 comprises a length of sleeved wire 9 having a connection terminal 10 at one end and insulating cap 11. The insulated end of the wear indicator 7 is secured in a hole 1 2 in the brake pad 3, which hole 1 2 is located adjacent the backing plate 5. In this position the wear indicator is protected from the brake disc 2 until the brake pad 2 is worn right down to it. When this occurs the brake pad 3 is in need of replacement and this is indicated by an indicator device 1 3 located on the vehicle dashboard (not shown). When the brake disc 2 reaches the wear indicator 7 it strips of the insulation covering it, exposing the bare wire underneath. The brake disc 2 is earth through the vehicle chassis (not shown) and thus the circuit including the wear indicator device 1 3 is closed turning the wear indicator device on. As stated hereinbefore the brake pads 3 and 4 are of metal and thus it is essential, if the wear indicator is to operate reliably, to ensure that it is insulated from the brake pad in which it is mounted. To this end the insulating cap 11 is provided on the end of the sleeved wire 9 to be mounted in the brake pad 3. The insulating cap 11 may be comprised of any insulating material, but prefera bly is comprised of a plastics material or rubber material which will fit on the sleeved wire 9 securely and bond in the hole 1 2 so as to prevent the wear indicator 1 from being pulled from the hole 1 2 in use. To this end the insulating cap 11 maybe bonded to the end of the sleeved wire 9 or may be integrally moulded thereon. It will be appreciated that throughout this specification the use of the term "brake pad" is intended to encompass brake shoes. CLAIMS
1. A brake pad wear indicator for use with metal brake pads, comprising a length of sleeved wire adapted to be connected at one end to the high side of a power supply via a wear indicator device and the other end of which is intended in use to be secured in the brake pad at a point thereof corresponding to the brake pad being worn away, wherein an insulating cap is secured to the end of the sleeved wire intended to be secured in the brake pad to prevent the sleeved wire shorting through the metal brake pad and to facilitate securing the said end in the brake pad.
2. A wear indicator as claimed in claim 1 wherein the insulating cap is bonded to the sleeved wire.
3. A wear indicator as claimed in claim 1 wherein the insulating cap is moulded onto the end of the sleeved wire.
4. A brake arrangement comprising a brake pad, a brake pad wear indicator device and a wear indicator as claimed in any one of claims 1 to 3, said insulating cap of the wear indicator being secured in the brake pad at a point thereof corresponding to the brake pad being worn away and the other end of said wear indicator being electrically connected to the brake pad wear indicator device.
5. A brake arrangement as claimed in claim 4 wherein the brake pad is a metal brake pad.
GB08330236A 1983-11-12 1983-11-12 Brake pad wear indicator Withdrawn GB2149034A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08330236A GB2149034A (en) 1983-11-12 1983-11-12 Brake pad wear indicator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08330236A GB2149034A (en) 1983-11-12 1983-11-12 Brake pad wear indicator

Publications (2)

Publication Number Publication Date
GB8330236D0 GB8330236D0 (en) 1983-12-21
GB2149034A true GB2149034A (en) 1985-06-05

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08330236A Withdrawn GB2149034A (en) 1983-11-12 1983-11-12 Brake pad wear indicator

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GB (1) GB2149034A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0559563A1 (en) * 1992-03-03 1993-09-08 Compagnie Plastic Omnium Method for producing a device for detecting wear of friction lining and device obtained by using this method
EP0611899A1 (en) * 1993-02-18 1994-08-24 Compagnie Plastic Omnium Device for detecting wear of friction lining
US5380419A (en) * 1986-09-10 1995-01-10 U.S. Philips Corp. Cathode-sputtering apparatus comprising a device for measuring critical target consumption

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1266276A (en) * 1969-04-24 1972-03-08
GB1301538A (en) * 1969-07-23 1972-12-29
GB1360768A (en) * 1972-05-05 1974-07-24 Dba Sa Wear detecting device for friction linings
GB1394822A (en) * 1971-05-21 1975-05-21 Girling Ltd Brake pad and a wear indicator therefor
EP0015889A1 (en) * 1979-03-09 1980-09-17 DON INTERNATIONAL S.A. Société Anonyme Wear indicator for brake pads
EP0032071A2 (en) * 1979-12-28 1981-07-15 Abex Equipement S.A. Wear indicator for disk brakes
EP0054480A1 (en) * 1980-12-16 1982-06-23 Abex Equipement S.A. Disk brake pad wear indicator device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1266276A (en) * 1969-04-24 1972-03-08
GB1301538A (en) * 1969-07-23 1972-12-29
GB1394822A (en) * 1971-05-21 1975-05-21 Girling Ltd Brake pad and a wear indicator therefor
GB1360768A (en) * 1972-05-05 1974-07-24 Dba Sa Wear detecting device for friction linings
EP0015889A1 (en) * 1979-03-09 1980-09-17 DON INTERNATIONAL S.A. Société Anonyme Wear indicator for brake pads
EP0032071A2 (en) * 1979-12-28 1981-07-15 Abex Equipement S.A. Wear indicator for disk brakes
EP0054480A1 (en) * 1980-12-16 1982-06-23 Abex Equipement S.A. Disk brake pad wear indicator device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5380419A (en) * 1986-09-10 1995-01-10 U.S. Philips Corp. Cathode-sputtering apparatus comprising a device for measuring critical target consumption
EP0559563A1 (en) * 1992-03-03 1993-09-08 Compagnie Plastic Omnium Method for producing a device for detecting wear of friction lining and device obtained by using this method
EP0559562A1 (en) * 1992-03-03 1993-09-08 Compagnie Plastic Omnium Device for detecting wear of friction lining
FR2688561A1 (en) * 1992-03-03 1993-09-17 Plastic Omnium Cie METHOD FOR PRODUCING A DEVICE FOR DETECTING WEAR OF FRICTION LININGS AND DEVICE OBTAINED BY IMPLEMENTING SAID METHOD
FR2689588A1 (en) * 1992-03-03 1993-10-08 Plastic Omnium Cie Friction pad wear detector e.g. for car brake
EP0611899A1 (en) * 1993-02-18 1994-08-24 Compagnie Plastic Omnium Device for detecting wear of friction lining
FR2701743A1 (en) * 1993-02-18 1994-08-26 Plastic Omnium Cie Friction lining wear detection device.

Also Published As

Publication number Publication date
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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)