EP0115960A1
Expired / Lapsed
EP
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Automatic slack adjuster Mk.II
Assignee: Siemens Mobility Ltd
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Filing: 1984-02-02
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Granted: —
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Expires: 2004-02-02
Abstract
Abstract This invention relates to an automatic slack adjuster particularly but not exclusively for automative vehicle braking systems. In the slack adjuster, input member A and hub 1 are coupled to output member 2 by a main clutch driven ring 13 mounted on output member 2 by helical threads 13A. The hub 1 is also coupled via a fine toothed positive sensor clutch to clearance control mechanism. This sensor clutch comprises an innerclutch ring 3, fixed to hub 1, and an outer clutch plate consisting of fine toothed inner ring 4 and co-operating with ring 8 with a predetermined degree of lost motion. Ring 8 acts as a ground datum for clearance control. Moving input lever A out of the paper as shown in Fig. 1 produces a rotation in a sense which with a right-hand helix angle spindle will urge clutch 13 into more intimate engagement with hub 1 generating an axial force towards the right of Fig. 1 which is fed through ground datum ring 8 and into sensor clutch spring 9 tending to urge them to the right permitting disengagement of fine clutch teeth T on ring 4 from clutch teeth formed directly in a recess in hub 2. There may be for example 720 fine teeth similar to conventional file teeth.
Inventors
- 👤 Geoffrey Robinson Tregoning
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 21:16
CPC Classifications
F; F16; F16D; F16D66/00; F16D66/02; F16D65/00; F16D65/38; F16D65/40; F16D65/52; F16D65/60
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
151 words
An automatic slack adjuster mechanism which includes an input member (A,l) pivotable in opposite directions about an axis to apply and release respectively a brake-applying force; an output member (2) also pivotable in opposite directions about the axis to transmit said force to brake applying means; a force transmitting member (13) threadedly engaged around the output member and having a clutch face (13B), engaged with a corresponding clutch face (lA) on the input member (1), and brake clearance determining means having a clutch (3, 4), a first part (3) of said clutch being fixed to the output member (1), a second part (4) of said clutch, normally drivingly engaged with the first part, being permitted limited lost motion with respect to a datum point on a fixed part (8) of the brake assembly, the limited lost motion corresponding to a predetermined brake clearance, said clutch (3, 4) being a positive clutch.
Claim 2
Dependent Claim
151 words
An automatic slack adjuster mechanism which includes an input member (A,l) pivotable in opposite directions about an axis to apply and release respectively a brake-applying force; an output member (2) also pivotable in opposite directions about the axis to transmit said force to brake applying means; a force transmitting member (13) threadedly engaged around the output member and having a clutch face (13B), engaged with a corresponding clutch face (lA) on the input member (1), and brake clearance determining means having a clutch (3, 4), a first part (3) of said clutch being fixed to the output member (1), a second part (4) of said clutch, normally drivingly engaged with the first part, being permitted limited lost motion with respect to a datum point on a fixed part (8) of the brake assembly, the limited lost motion corresponding to a predetermined brake clearance, said clutch (3, 4) being a positive clutch.
Claim 3
Dependent Claim
80 words
An automatic slack adjuster according to Claim 1 and in which the positive clutch (3, 4) is employed to drive the output member (2) a few degrees between the point of release and positive clearance of the brake shoes, utilising a drive torque derived from brake cylinder or other pull-off springs acting through the input member, said torque augmenting the release torque normally - developed in the brake cam shaft by virtue of the usual shoe or other pull-off springs.
Claim 4
Dependent Claim
31 words
An automatic slack adjuster according to Claim 1 or Claim 2 and in which said positive clutch comprises a pair of clutch plates (3, 4) each equipped with fine teeth (T).
Claim 5
Dependent Claim
20 words
An automatic slack adjuster-according to Claim 3 in which there are at least 10 teeth per 5° of clutch face.
Claim 6
Dependent Claim
64 words
An automatic slack adjuster according to Claim 1 and in which said positive clutch (3, 4) is a toothed clutch with multiple miniature teeth (T) providing a large number of small steps which are so small that, for practical purposes, the toothed clutch functions like a stepless clutch but, at the same time, positive engagement is provided to enable increased torque to be transmitted.
Claim 7
Dependent Claim
69 words
An automatic slack adjuster according to Claim 3 or Claim 4 in which said one of the toothed cluch plates (4) is formed as a ring-like part with provision (7A) for lost motion between it and a co-operating part (8) forming a ground datum, the datum part (8) being axially free but non-rotatable with respect to some fixed part of a brake assembly with which the adjuster is used.
Claim 8
Dependent Claim
70 words
An automatic slack adjuster according to Claim 6 and in which one of the clutch plates (3) is fixed and is a single ring, and the other clutch plate (4) is movable and comprises a ring (4C) having a radially outwardly extending wall or flange engageable, via lugs (4A), with abutments (4B) on the input member (1) and having limited lost motion with respect to the ground datum part (8).
Claim 9
Dependent Claim
66 words
An automatic slack adjuster according to Claim 6 or Claim 7 and in which the lost motion is achieved by means of dowels (5) which engage in half round holes in a first ring (4C) forming a portion of one clutch plate and in elongated arcuate slots (8A, 8B) in a second ring formed, alternatively, integral with or rigidly attached to, the ground datum part (8).
Claim 10
Dependent Claim
81 words
An automatic slack adjuster according to Claim 8 and in which, to achieve variable amounts of lost motion, the arcuate slots (8A, 8B) are arranged around the perimeter of the second ring (8) and the lengths of these slots (8A, 8B) increase from one slot to the next around the perimeter whereby it is possible to select any required degree of lost motion by engagement of a dowel (5) in a half round hole opposite to an appropriate length arcuate slot.
Claim 11
Dependent Claim
27 words
An automatic slack adjuster according to any preceding claim and including a lever (15) operating a ball and slot arrangement for release of the lost motion device.
Claim 12
Dependent Claim
20 words
An automatic slack adjuster according to any preceding claim when used in a brake mechanism for a heavy road vehicle.
References Cited (Backward Citations)
US2385621A
Cited
US2697497A
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GB1394666A
Cited
GB1538848A
Cited
FR2414151A1
Cited
GB2088979A
Cited
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