GB2165927A - Stowing handbrake lever - Google Patents

Stowing handbrake lever Download PDF

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Publication number
GB2165927A
GB2165927A GB08525922A GB8525922A GB2165927A GB 2165927 A GB2165927 A GB 2165927A GB 08525922 A GB08525922 A GB 08525922A GB 8525922 A GB8525922 A GB 8525922A GB 2165927 A GB2165927 A GB 2165927A
Authority
GB
United Kingdom
Prior art keywords
pawl
lever
button
brake
portions
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Withdrawn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
GB08525922A
Other versions
GB8525922D0 (en
Inventor
Brian John Spooner
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.)
Group Lotus PLC
Original Assignee
Group Lotus PLC
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
Priority claimed from GB848426616A external-priority patent/GB8426616D0/en
Application filed by Group Lotus PLC filed Critical Group Lotus PLC
Priority to GB08525922A priority Critical patent/GB2165927A/en
Publication of GB8525922D0 publication Critical patent/GB8525922D0/en
Publication of GB2165927A publication Critical patent/GB2165927A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/02—Brake-action initiating means for personal initiation
    • B60T7/08—Brake-action initiating means for personal initiation hand actuated
    • B60T7/10—Disposition of hand control
    • B60T7/102—Disposition of hand control by means of a tilting lever
    • B60T7/104—Disposition of hand control by means of a tilting lever with a locking mechanism
    • B60T7/105—Disposition of hand control by means of a tilting lever with a locking mechanism the lock being released by means of a push button
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05G—CONTROL DEVICES OR SYSTEMS INSOFAR AS CHARACTERISED BY MECHANICAL FEATURES ONLY
    • G05G5/00—Means for preventing, limiting or returning the movements of parts of a control mechanism, e.g. locking controlling member
    • G05G5/12—Means for preventing, limiting or returning the movements of parts of a control mechanism, e.g. locking controlling member for holding members in an indefinite number of positions, e.g. by a toothed quadrant
    • G05G5/14—Means for preventing, limiting or returning the movements of parts of a control mechanism, e.g. locking controlling member for holding members in an indefinite number of positions, e.g. by a toothed quadrant by locking a member with respect to a fixed quadrant, rod, or the like
    • G05G5/18—Means for preventing, limiting or returning the movements of parts of a control mechanism, e.g. locking controlling member for holding members in an indefinite number of positions, e.g. by a toothed quadrant by locking a member with respect to a fixed quadrant, rod, or the like by positive interengagement, e.g. by a pawl

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Braking Elements And Transmission Devices (AREA)
  • Mechanical Control Devices (AREA)

Abstract

A vehicle handbrake lever mechanism has a hand lever which pivots about a ratchet toothed quadrant (11) and carries with it a pawl (13) which, as the lever is moved in one direction to apply the brake, rides over the ratchet teeth; engages finally in one of those teeth to hold the brake on. The pawl (13) is pivotally mounted with respect to the lever and is coupled to a pawl disengaging button (16) such that depression of said button causes rotation of said pawl. The pawl has to be positively disengaged by depression of the button and held out of engagement (conventionally by depressing a button carried towards or more usually at the projecting end of the lever) for the lever to be moved in the opposite direction to release the brake. The hand lever (12) is made in two portions (12a, 12b) which are pivoted to one another about an axis running across the general axis along which the composite lever extends. One of those portions (12a) carries the pawl (13) and incorporates the quadrant pivot (15) while the other portion (12b) carries the pawl disengaging button (16). The pawl disengaging button (16) is permanently coupled to said pawl (13). The two portions (12a, 12b) cooperate to apply the brake; but, with the brake applied and held on, the button carrying portion (12b) can pivot away from the pawl carrying portion (12a) of the lever without disengaging the pawl (13). <IMAGE>

Description

SPECIFICATION Stowing handbrake lever BackBround to the Invention The invention relates to vehicle handbrake lever mechanisms of the kind in which a hand lever pivots about a ratchet toothed quadrant and carries with it a pawl which, as the lever is moved in one direction to apply the brake, rides over the ratchet teeth; engages finally in one of those teeth to hold the brake on; and has to be positively disengaged and held out of engagement (conventionally by depressing a button carried towards or more usually at the projecting end of the lever) for the lever to be moved in the opposite direction to release the brake.
Review of the Prior Art It has been previously proposed in UK Patent Specification Number 1 223 088 to provide a hand lever for use with such a mechanism which is made in two portions which are pivoted to one another about an axis running across the general axis along which the composite lever extends; one of those portions carries the pawl and incorporates the quadrant pivot whilst the other portion carries the pawl disengaging button; the two portions co-operate to apply the brake; but, with the brake applied and held on, the button carrying portion can pivot away from the pawl carrying portion of the lever without disengaging the pawl.
Thus a handbrake lever is provided which can be stowed away out of its projecting position whilst still engaged.
However, the mechanism for disengaging the pawl is not robust and long-lasting.
A rod extends from the pawl disengaging button within the button carrying portion to abut against the pivotally mounted pawl. A leaf spring attached to the rod bears against an arcuate surface of the pawl to hold the pawl against the rod when the lever is in its extended protruding state. When the button carrying portion is pivoted away from the pawl carrying portion the leaf spring slides around the pawl until it has disengaged from the pawl so that there is no connection between the button and the pawl in this position. This prevents the release of the brake in the stowed position of the lever. The major problem in this is that it is a mechanism which could fail due to failure of the leaf spring.If the leaf spring breaks (which it would be likely to do after multiple applications of the brake, the pawl would no longer be held against the rod and there would be no control of the movement of the pawl.
Summary of the Invention According to this invention there is provided a handbrake lever for use with a mechanism in which a hand lever pivots about a ratchet toothed quadrant and carries with it a pawl which, as the lever is moved in one direction to apply the brake, rides over the ratchet teeth; engages finally in one of those teeth to hold the brake on; the pawl is pivotally mounted with respect to the lever and is coupled to a pawl disengaging button such that depression of said button causes rotation of said pawl; and the pawl has to be positively disengaged by depression of the button and held out of engagement for the lever to be moved in the opposite direction to release the brake; in which, the hand lever is made in two portions which are pivoted to one another about an axis running across the general axis along which the composite lever extends; one of those portions carries the pawl and incorporates the quadrant pivot whilst the other portion carries a pawl disengaging button; the pawl disengaging button is permanently coupled to said pawl; the two portions co-operate to apply the brake; but, with the brake applied and held on, the button carrying portion can pivot away from the pawl carrying portion of the lever without disengaging the pawl.
This is a much more robust arrangement where the button and pawl are permanently coupled so that there is no need for the provision of leaf springs and much less risk of failure of the mechanism.
A hand lever embodying the invention is particularly advantageous when installed in a road going motor vehicle such as that currently manufactured in the United Kingdom by Lotus Cars Limited and marketed under the Model designation "Lotus Esprit" (LOTUS and ESPRIT are registered trade marks). In this vehicle the handbrake lever is mounted on the body sill adjacent the driver's door. When the brake is fully applied, the conventional hand lever projects almost vertically from the sill. In that attitude it constitutes an irritating obstacle to the driver's legs when he attempts to swing himself into and out of the vehicle. A hand lever embodying the invention can simply pivot flat against the substantially horizontal sill once the brake has been applied, and no longer constitutes an obstacle to the driver entering and leaving the vehicle cabin.
Preferably the two lever portions move as one when applying the brake. It is theoretically possible to devise an arrangement in which the button carrying portion moves gradually towards and eventually against the pawl carrying portion as the brake is progressively applied. It is clearly simpler and potentially more trouble free to utilise an arrangement in which, to apply the brake, the button carrying portion pivots fully into contact with the pawl carrying portion of the lever before the lever starts to move.
It is also preferred, again largely for reasons of simplicity and ease of manufacture, to coin cide the pivot connecting the two lever portions, with the pivot about which the pawl moves as it engages and is disengaged from the ratchet teeth.
Advantageously the geometry of the arrangement in use is such that the button carrying portion, as it pivots away from the pawl carrying lever portion with the brake held on, progressively covers the button itself; and subsequently progressively uncovers the button as it pivots back towards the pawl carrying portion prior to the brake being released.
With a conventional hand lever, the fact that the lever is projecting up at an appreciable angle from the vehicle floor or transmission tunnel gives a ready visual indication that the brake is on. With a hand lever embodying the invention, it could wrongly be assumed that the brake was off when in fact the brake had been fully applied and the button carrying lever portion had simply been pivoted away from the rest of the hand lever to lie flat against the vehicle floor or transmission tunnel.
Advantageously also, a guard bridges any gap which opens up between adjacent (for example abutting) ends of the two lever portions as the button carrying portion pivots away from the pawl carrying portion. Such a guard, fixed for example to one of the lever portions and projecting over the other one, minimises the risk of a user' s fingers or clothing being trapped as the two lever portions subsequently approach one another again. Even when the pivoting region is masked by a rubber or leather gaiter, a suitably positioned and proportioned guard will minimise any risk of the necessarily voluminous gaiter being trapped between the two lever portions.
Brief Description of the Drawings In the accompanying drawings: Figure 1 shows diagramatically one vehicle handbrake lever mechanism incorporating a lever which embodies the invention, the mechanism being depicted as the brake is being applied; and Figure 2 shows the same mechanism with the brake fully applied, and held on, and with the button carrying portion of the hand lever subsequently pivoted away from the rest of the lever.
Description of the Preferred Embodiment The handbrake mechanism illustrated is currently the best way known to the applicants of putting the invention into practice. It is of course only one example of forms which the invention might take within the broad inventive concept.
The mechanism comprises a hand lever pivoting about a ratchet toothed quadrant 11 and moving anticlockwise to apply the brake and clockwise to subsequently release it. The lever 12 carries a pawl 13 which is pivoted to the lever at 14.
As the lever moves anticlockwise about its quadrant pivot 15 to apply the brake, the nose of the pawl 13 rides over the ratchet teeth and engages finally in one of those teeth to hold the brake on.
To move the lever clockwise to release the brake, the pawl 13 has to be positively disengaged and then held out of engagement. A thumb operated cylindrical button 16 fits into and projects from the similarly cylindrical projecting barrel end 17 of the lever 12 and is spring loaded to resist depression. The button 16 and the pawl 13 are permanently coupled by a rod 18 which is elongate and rigid and is pivoted at one end to the button 16 and at its other end to the pawl 13. When sufficient depressing force is applied to the button 16 to overcome the spring resistance, the rod 18 moves linearly to swing the pawl 13 anticlockwise about its pivot 14 and disengage it from the ratchet teeth of the quadrant 11.
Maintaining the pressure on the button 16 holds the pawl 13 out of engagement with the ratchet teeth and enables the lever 12 to be moved clockwise to release the brake.
The rod 18 and pawl 13 are both enshrouded by the lever 12, as is the spring loading mechanism (not illustrated) of the button 16; all in known manner which need not be detailed for the intended skilled addressee of this specification.
The lever 12, however, departs from conventional practice in that it is constructed of two portions 12a, 1 2b which are pivoted to one another about an axis coinciding with the pivot 14 about which the pawl 13 moves.
The lever portion 1 2a carries the pawl 13 and also incorporates the main quadrant pivot 15.
Portion 1 2b comprises the greater part of the overall length of the lever, beyond pivot 15, and carries the button 16 and its spring loading mechanism.
The adjacent ends of the two lever portions 12a, 12b abut one another when the lever is moved, as illustrated in Figure 1, anticlockwise to apply the brake. In that abutting relation the two lever portions 12a, 12b define a composite lever which has a generally linear and elongate axis.
With the brake fully applied, and held on, as illustrated in Figure 2, portion 1 2b of the lever can then pivot about pivot point 14, away from portion 12a, carrying with it the button 16 but without disengaging the pawl 13. A gap then opens up between the previously abutting ends of the two lever portions 12a, 12b. A guard 19, fixed to the top of portion 12a, projects over the gap and bridges it above portion 12b.
A leather gaiter 21 covers the pivoting region of the mechanism and extends along the hand lever as far as the base of a moulded finger-indented grip 22 which occupies the re mainder of the projecting length of the lever.
The gaiter 21 is necessarily voluminous, because it is fixed at each of its opposite ends, respectively to the base of the whole mechanism and to the base of the grip 22 and it has to stretch to accommodate the pivoting movement of lever portion 1 2b away from portion 12a in the Figure 2 mode. The bridge 19 prevents any tendency for the gaiter material to be trapped between the two lever portions as the portion 1 2b is subsequently returned to its Figure 1 position.
As illustrated, the geometry of the whole arrangement is such that the lever portion 12b, as it pivots away from the rest of the lever 12a with the brake held on, progressively covers the button 16 and prevents the button from being depressed until lever portion 1 2b has been returned to its Figure 1 position.

Claims (6)

1. A handbrake lever for use with a mechanism in which a hand lever pivots about a ratchet toothed quadrant and carries with it a pawl which, as the lever is moved in one direction to apply the brake, rides over the ratchet teeth; engages finally in one of those teeth to hold the brake on; the paw is pivotally mounted with respect to the lever and is coupled to a pawl disengaging button such that depression of said button causes rotation of said pawl; and the pawl has to be positively disengaged by depression of the button and held out of engagement for the lever to be moved in the opposite direction to release the brake; in which, the hand lever is made in two portions which are pivoted to one another about an axis running across the general axis along which the composite lever extends; one of those portions carries the pawl and incorporates the quadrant pivot whilst the other portion carries a pawl disengaging button; the pawl disengaging button is permanently coupled to said pawl; the two portions co-operate to apply the brake; but, with the brake applied and held on, the button carrying portion can pivot away from the pawl carrying portion of the lever without disengaging the pawl.
2. A handbrake lever according to Claim 1, in which the two lever portions move as one when applying the brake.
3. A handbrake lever according to Claim 1 or 2, in which the pivot connecting the two lever portions coincides with the pivot about which the pawl moves as it engages and is disengaged from the ratchet teeth.
4. A handbrake lever according to any one of Claims 1, 2 or 3, in which the button carrying portion, as it pivots away from the pawl carrying lever portion with the brake held on, progressively covers the button itself; and subsequently progressively uncovers the button as it pivots back towards the pawl carrying portion prior to the brake being released.
5. A handbrake lever according to any one of the preceding Claims, in which a guard bridges any gap which opens up between adjacent ends of the two lever portions as the button carrying portion pivots away from the pawl carrying portion.
6. A handbrake lever arranged substantially as described herein with reference to, and as illustrated in, Figures 1 and 2 of the accompanying drawings.
GB08525922A 1984-10-20 1985-10-21 Stowing handbrake lever Withdrawn GB2165927A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08525922A GB2165927A (en) 1984-10-20 1985-10-21 Stowing handbrake lever

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB848426616A GB8426616D0 (en) 1984-10-20 1984-10-20 Stowing handbrake lever
GB08525922A GB2165927A (en) 1984-10-20 1985-10-21 Stowing handbrake lever

Publications (2)

Publication Number Publication Date
GB8525922D0 GB8525922D0 (en) 1985-11-27
GB2165927A true GB2165927A (en) 1986-04-23

Family

ID=26288357

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08525922A Withdrawn GB2165927A (en) 1984-10-20 1985-10-21 Stowing handbrake lever

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GB (1) GB2165927A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4982918A (en) * 1988-01-29 1991-01-08 British Aerospace Public Limited Company Force sensitive aircraft throttle with feedback

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4982918A (en) * 1988-01-29 1991-01-08 British Aerospace Public Limited Company Force sensitive aircraft throttle with feedback

Also Published As

Publication number Publication date
GB8525922D0 (en) 1985-11-27

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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)