GB2373828A - Self-adjusting mechanism - Google Patents

Self-adjusting mechanism Download PDF

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Publication number
GB2373828A
GB2373828A GB0105278A GB0105278A GB2373828A GB 2373828 A GB2373828 A GB 2373828A GB 0105278 A GB0105278 A GB 0105278A GB 0105278 A GB0105278 A GB 0105278A GB 2373828 A GB2373828 A GB 2373828A
Authority
GB
United Kingdom
Prior art keywords
piston
drive member
mechanism according
friction
spring
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Withdrawn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
GB0105278A
Other versions
GB0105278D0 (en
Inventor
Simon Bull
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.)
Prodrive 2000 Ltd
Original Assignee
Prodrive 2000 Ltd
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 Prodrive 2000 Ltd filed Critical Prodrive 2000 Ltd
Priority to GB0105278A priority Critical patent/GB2373828A/en
Publication of GB0105278D0 publication Critical patent/GB0105278D0/en
Publication of GB2373828A publication Critical patent/GB2373828A/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Withdrawn legal-status Critical Current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
    • F16D65/00—Parts or details
    • F16D65/38—Slack adjusters
    • F16D65/40—Slack adjusters mechanical
    • F16D65/62—Slack adjusters mechanical self-acting in both directions for adjusting excessive and insufficient play
    • F16D65/64—Slack adjusters mechanical self-acting in both directions for adjusting excessive and insufficient play by means of direct linear adjustment
    • 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
    • F16D25/00—Fluid-actuated clutches
    • F16D25/12—Details not specific to one of the before-mentioned types
    • 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
    • F16D65/00—Parts or details
    • F16D65/38—Slack adjusters
    • F16D65/40—Slack adjusters mechanical
    • F16D65/52—Slack adjusters mechanical self-acting in one direction for adjusting excessive play
    • F16D65/54—Slack adjusters mechanical self-acting in one direction for adjusting excessive play by means of direct linear adjustment

Landscapes

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

Abstract

A self adjusting mechanism includes a fluid operated annular piston 18 with seals 20, 22 engaging a cavity 16 wall and operatively connected to an annular drive member 24 through a spring 32 and a friction member in the form of sleeve 28. The piston moves the drive member on contact of its face 26 with the drive member. The friction member is moveable against a frictional resistance relative to the drive member and said resistance is selected to be more than the resistence between the piston and its housing 14. The spring biases the piston away from the drive member when the piston is not operational and the piston is spaced from the drive member by a predetermined clearance or play. Application in brakes and clutches.

Description

Self-Adjusting Mechanism
The present invention relates to a self-adjusting mechanism and in particular to a mechanism for use in conjunction with a fluid operated actuator.
According to the present invention there is provided a mechanism to enable a predetermined off-load spacing between a fluid operated piston provided in a housing and a drive member adapted to, in use, be contacted and moved by said piston, the mechanism comprising a movable friction member and a spring, the friction member being provided on the drive member and the spring arranged between the friction member and piston, wherein the static frictional force between the friction member and the drive member is greater than the static frictional force between the piston and housing, and the spring is adapted to bias the piston from the drive member in the absence of fluid pressure being applied to the piston.
In a preferred embodiment the drive member and friction member are annular. In such an embodiment the friction member may be provided annularly within or, alternatively, outside the drive member. The friction member preferably includes an elastomeric circumferential seal.
An embodiment of the present invention will now be described with reference to the accompanying drawing (Figure 1) which shows a partial cross-sectional view of a fluid operated actuator system generally designated 10 It will be understood that the system is essentially cylindrical about the centreline 12. The system 10 comprises a housing 14 having a cavity 16 within which there is provided a piston 18. The piston includes inner and outer circumferential seals 20,22. Facing the piston 18 is an annular member 24 adapted to be moved by the piston 18 upon contact with a portion of the piston face 26. Provided on the inside of the annular member 24 is a friction member in the form of a close fitting sleeve 28. The sleeve 26 is provided with a circumferential seal 30.
Extending between the sleeve 26 and the piston face 26 is a spring 32.
T In use, the piston 18 is movable towards the annular member 24 by the application fluid pressure to the rear face 34 thereof via a conduit 36 of the housing 14. Moveme of the piston 18 towards the annular member 24 is resisted by a combination of t) static friction between the seals 20,22 and the cavity 16, and the reactive force of tl spring 32 acting on the piston face 26. As the fluid pressure increases the force apple to the piston 18 is sufficient to overcome the static friction of the seals 20,22 and tl resistive force of the spring 32 and hence the piston 18 is moved towards the annul. member 24.
Movement of the piston 18 compresses the spring 32 against the friction member 2 until the force applied by the compressed spring 32 is greater than the static friction. force between the sleeve seal 30 and the annular member 24. Further movement of tlpiston 18 towards the annular member 24 results in movement of the friction memo ( 28 relative to the annular member 24.
Continued movement of the piston 18 results in the contact of the piston face 26 wit the annular member 24 and hence the transmission of force applied by the piston 1
through the annular member 24. In use, the annular member 24 may be arranged so a zn to move a brake pad into contact with a brake disc.
Removal of the fluid pressure applied to the rear face 34 of the piston 18 results i reverse movement of the piston 18 by a distance equal to the extension of the spring 3 the force stored in the spring 32 being sufficient to overcome the static friction betwee the seals 20,22 and the cavity 16.
The present invention ensures that, upon the removal of fluid pressure to the piston I the piston is moved from annular member 24 by a predetermined distance irrespectiv of the spacing between the annular member 24 and the housing 14. Taking the exampl of the annular member 24 being adapted to contact a brake pad, the present inventio ensures that a predetermined amount of free play exists between the piston 18 an < annular member 24 under all brake pad wear conditions. The present invention i equally applicable to a fluid operated clutch actuator system.

Claims (9)

Claims
1. Self-adjusting mechanism comprising : a fluid operated piston, a housing for the piston, a drive member arranged to be moved by the piston when the piston is operated, a friction member located on the drive member, and a spring which extends between the piston and the friction member, the mechanism being arranged such that the frictional resistance between the friction member and the driven member is greater than the frictional resistance between the piston and its housing, the spring being arranged to bias the piston for movement away from the drive member when the piston is not under fluid pressure, whereby the mechanism enables the piston to be spaced from the drive member when non-operational.
2. A mechanism according to claim 1 wherein the piston is annularly arranged and the drive member is correspondingly shaped.
3. A mechanism according to claim I or 2 wherein the friction member comprises an elastomeric seal.
4. A mechanism according to any one of the preceding claims wherein the friction member is moveable relative to the drive member when the force applied to the friction member exceeds the frictional resistance between the friction member and the drive member.
5. A mechanism according to any one of the preceding claims wherein the piston causes the drive member to move when the piston engages the drive member.
6. A mechanism according to any one of the preceding claims wherein the spring allows relative movement between the piston and the drive member, such movement being of the piston towards the drive member in an operational movement of the piston, and away from the drive member under spring action when the piston is non-operational.
7. A mechanism according to any one of the preceding claims wherein the drive member is arranged to be moveable to operate a brake including a wearable brake pad.
8. A mechanism according to any one of the preceding claims wherein the drive member is arranged to be operable to operate a clutch.
9. A self-adjusting mechanism substantially as described with reference to the drawing.
GB0105278A 2001-03-05 2001-03-05 Self-adjusting mechanism Withdrawn GB2373828A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0105278A GB2373828A (en) 2001-03-05 2001-03-05 Self-adjusting mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0105278A GB2373828A (en) 2001-03-05 2001-03-05 Self-adjusting mechanism

Publications (2)

Publication Number Publication Date
GB0105278D0 GB0105278D0 (en) 2001-04-18
GB2373828A true GB2373828A (en) 2002-10-02

Family

ID=9909909

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0105278A Withdrawn GB2373828A (en) 2001-03-05 2001-03-05 Self-adjusting mechanism

Country Status (1)

Country Link
GB (1) GB2373828A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT521981A4 (en) * 2019-04-24 2020-07-15

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1393866A (en) * 1973-03-19 1975-05-14 Gen Motors Corp Fluid-operable actuator assemblies
DE2610651A1 (en) * 1976-03-13 1977-09-15 Knorr Bremse Gmbh Hydraulic vehicle brake automatic wear adjuster - limits retraction of piston by frictionally supported stop consisting of annular cap on cylinder
GB2146716A (en) * 1983-09-14 1985-04-24 Ford Motor Co Disc brake retraction device
EP0864772A1 (en) * 1997-03-12 1998-09-16 Sumitomo Electric Industries, Ltd. Disk brake

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1393866A (en) * 1973-03-19 1975-05-14 Gen Motors Corp Fluid-operable actuator assemblies
DE2610651A1 (en) * 1976-03-13 1977-09-15 Knorr Bremse Gmbh Hydraulic vehicle brake automatic wear adjuster - limits retraction of piston by frictionally supported stop consisting of annular cap on cylinder
GB2146716A (en) * 1983-09-14 1985-04-24 Ford Motor Co Disc brake retraction device
EP0864772A1 (en) * 1997-03-12 1998-09-16 Sumitomo Electric Industries, Ltd. Disk brake

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT521981A4 (en) * 2019-04-24 2020-07-15
AT521981B1 (en) * 2019-04-24 2020-07-15

Also Published As

Publication number Publication date
GB0105278D0 (en) 2001-04-18

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)