VEHICULAR BRAKE SUSTAINING DEVICE

Abstract: A mechanical means of maintaining applied vehicular brakes, once these have been initially applied by means of a foot pedal. The means comprises an inelastic, flexible, elongate element which is in permanent contact with a brake pedal (1) and with the vehicle chassis (11) which lies in the general direction of depression of the pedal and a reversible activatable movement-preventing means which, when activated, acts in concert with the elongate element to form an inextendible physical link between the pedal and the chassis which physically prevents the depressed brake pedal from leaving its depressed position. In a preferred embodiment, the elongate element is a wire (9) wound on a spring-loaded spool (3) and the movement-preventing means is an electromagnet (13) which acts on the spool. The invention is useful for preventing "creep" of stationary automatic vehicles, and assisting in hill starts for manual vahicles.

Description: VEHICULAR BRAKE SUSTAINING DEVICE This invention relates to braking systems for vehicles, and more particularly to a mechanical means for maintaining a brake pedal in a depressed (brakes-on) position when the brakes have first been applied by foot. The concept of maintaining the brakes of a vehicle in the applied position without having to press continuously on the brake pedal is an attractive one. The ability to do this could prevent without effort the "creep" of vehicles having automatic transmissions. It could also remove a substantial part of the difficulty of making uphill-facing starts in a vehicle particularly a vehicle with manual transmission. There have already been many attempts to achieve this end. Many have been of the form of valves in the hydraulic brake lines of vehicles, these allowing the pressure generated by application of a foot pedal to be maintained. This, however, can involve considerable modification of a vehicle's hydraulic lines. Mechanical ways of achieving the same end avoid this problem and many have been devised. Typical examples can be found in United States Patents 4 076 093, 4 093 050, and 4 497 395; all of these documents describe competent (and often quite sophisticated) devices for maintaining applied foot brakes once these have first been applied by foot. I now disclose a relatively simple means of achieving this end. I therefore provide, according to the present invention a mechanical means of maintaining applied the brakes of a vehicle once these have been initially applied by depressing a foot pedal, by physically restraining the depressed pedal in its depressed position, the means comprising (a) at least one inelastic flexible elongate element which is in permanent contact with both the pedal and that part of the vehicle chassis which lies generally in the direction of depression of the pedal, and (b). at least one reversible activatable movement- preventing means which, when activated, acts in concert with the inelastic flexible elongate element to form, until activation is reversed, an inextendible physical link between the depressed pedal and that part of the vehicle chassis lying in the general direction of depression of the pedal. I have found that, not only is the means of this invention as efficacious as many more sophisticated means known to the art, but that it is also much cheaper to manufacture and easier to fit to a vehicle. The inelastic flexible elongate element used in my invention contacts both the pedal and the vehicle chassis which lies generally in the direction of depression of the pedal. It should be noted here that my use of the term "vehicle chassis" encompasses all parts of the vehicle structure which are rigidly fixed with respect to the basic chassis. When I say that the inelastic, flexible, elongate element "contacts" the pedal and the chassis, I mean that the contact may be either a fixed contact or a contact where movement is possible. The nature of such contact is entirely dependent on the type of elongate element used and the nature of the movement preventing means which with the " elongate element acts to prevent the pedal from returning from its depressed position. I. shall consider types of movement preventing means in more detail later in my specification. Typical "contacts" are these; (a) one end of the elongate element is fixed to the pedal and the other end to a device mounted on the chassis for taking up slack; (b) both ends of the elongate element are fixed to the chassis and it contacts the pedal via a contact element which allows for smooth, non-binding motion of the pedal in contact with and relative to the elongate element when the pedal is depressed; (c) both ends of the elongate element contact the pedal, one fixed and one via a device for taking up slack, the elongate means contacting the chassis via a ring or pulley fixed to the chassis. Other variants will be obvious to a person skilled in the art - it is evident, for example, that in the type (a) above, the positions of the fixed point and the device can be reversed. With regard to the contact element of type (b) , this can be, for example, a simple lateral protrusion of the pedal, this being profiled so as to allow smooth non-binding motion. This can be aided by coating the protrusion with a friction-reducing material such as PTFE or nylon. Alternatively, the contact element may be a pulley rotatably mounted on the pedal, or a suitably shaped shoe affixed thereto. The inelastic, flexible elongate element may be chosen from any suitable material known to the art. It may be, for example, rope, cord, wire or synthetic filament. In the case where both ends are fixed to the vehicle chassis, typically with one attachment on the bulkhead on which the brake pedal pivots and the other attachment in a convenient location, for example, under the dashboard, the elongate element will often be attached at the dashboard end via a spring which maintains the elongate element perpetually taut and in constant contact with the pedal. There are some specialised elongate elements of my invention which require specific types of points of contact. For example, if the elongate element is a bicycle-type chain, it may contact the pedal via a toothed sprocket rotatably mounted on the pedal. Similarly, if the elongate element is a toothed belt, the contact may be supplied by a correspondingly toothed wheel. A particularly useful embodiment is one where the element is a wire which is wound on a spring-loaded spool, the spring loading being such that it tends to retract the wire in the manner of a retractable flexible tape measure. This spool can be attached to the pedal and the wire to the bulkhead on which the pedal pivots (or vice versa) . The spring loading has insufficient strength of its own accord to depress the pedal, but sufficient to take up any slack when the pedal is depressed. The invention also comprises a reversible activatable movement preventing means which acts in concert with the elongate element so as to prevent any movement of the pedal away from a depressed position. As is suggested by the name, the movement-preventing means acts so as to restrict movement, and is activatable (either manually or automatically) and reversible (that is, it can be similarly deactivated) . The nature of the movement-preventing means depends entirely on the nature of the movement to be restricted. For example, it may be the linear movement of the elongate means which is to be prevented by the direct application of, for example, friction braking thereto. Alternatively, it may be the rotational movement of a rotatable component such as a toothed sprocket, toothed wheel or spool in the embodiments described hereinabove which is to be prevented. The movement-preventing means may be selected from among a wide range of possible mechanisms known to the art and activation/ deactivation may be achieved by vacuum, fluid pressure, mechanical, electromagnetic or other suitable means. I especially prefer electro¬ magnetic means. In the particularly useful spring-loaded spool embodiment described herein¬ above, the spool may be made of an electromagnetic material and be located in touching contact with an electromagnet, the energising of which would prevent the spool from turning. Many other possible variations of my invention will be obvious to a person skilled in the art. One such variation would be the use of two elongate elements. Thus, in the particularly useful embodiment described hereinabove, there could be a spool on either side of the pedal, each spool having its own wire and being connected to a different point on the bulkhead. Such an embodiment would allow the individual spools to be more compact. The invention will now be further described with reference to a particularly preferred embodiment. Figure 1 is a part longitudinal cross-section ' of a part of a vehicle showing the position of the brake pedal and a mechanical means according to the invention. Figure 2 is a cross-section of a mechanical means in a plane transverse to the longitudinal axis of the vehicle. Figure 3 is a cross-section of a mechanical means in a plane transverse to that of Figure 2 along the line A-A . Figure 4 is a cross-section of a mechanical means in a plane transverse to that of Figure 2 along the line B-B . A brake pedal 1 is pivotally mounted on a motor vehicle. To this pedal is rigidly fixed a flat drum 2, the axis of the drum being horizontal. Within this drum is a spool 3, this spool being made from a single piece of ferro¬ magnetic material and having the following configuration in sequence; a first cylindrical portion 4 of diameter relatively small compared to that of the drum, a first circular flange portion 5 having a diameter greater than that of the first cylindrical portion, a second cylindrical portion 6 of diameter greater than that of the first cylindrical portion but less than that of the first flange portion, and a second circular flange portion 7 whose diameter is almost that of the internal diameter of the drum. This spool is rotatably mounted coaxially with the drum on an axial bolt 8, the first cylindrical portion being adjacent to a flat end wall of the drum. A length of wire 9 is affixed to the spool and wound on the second cylindrical portion, the wire passing out of the drum through an orifice 10 and being fixed to an adjacent bulkhead at 11. Attached to the first cylindrical portion 4 is a spring 12 which seeks to turn the spool such that the wire is wound into the drum. This spring has insufficient force to pull the brake pedal itself, but it has sufficient force to make the spool take up the slack wire when the pedal is manually depressed. Within the drum is a ring-shaped electromagnet 13, this being coaxial with the spool and being rigidly fixed such that it has sliding contact with the second circular flange portion 7 of the spool. When energised, the electromagnet clamps itself to the second circular flange, prohibiting rotational movement of the spool. Thus, if the electromagnet is energised when the brake pedal is in the depressed position, the pedal will be locked in place until the energising current is removed. Details of suitable electrical circuitry for the energising of electromagnets are well known to the art and I shall not describe them here. There are many obvious variations which can be made to the preferred embodiment without affecting its performance. For example, the spool need not be a single piece of ferromagnetic material but may comprise several sections which can be affixed together. Similarly, only that part of the spool which is adjacent to the electromagnet need be of ferromagnetic material; the other parts of the spool may be, for example, wood, plastics or aluminium. Similarly, the mechanical means could be fitted to the bulkhead of the vehicle and the free end of the wire to the pedal. .

Claims: CLAIMS 1. A mechanical means of maintaining applied the brakes of a vehicle, once those have been initially applied by depressing a foot pedal, by physically restraining the depressed pedal in its depressed position, characterised in that the means comprises (a) at least one inelastic flexible elongate element which is in permanent contact with both the pedal and that part of the vehicle chassis which lies generally in the direction of depression of the pedal; and (b) at least one reversible activatable movement-preventing means which, when activated, acts in concert with the inelastic flexible elongate element to form, until activation is reversed, an inextendible physical link between the depressed pedal and that part of the vehicle chassis lying in the general direction of depression of the pedal. 2. A mechanical means according to claim 1, characterised in that the inelastic flexible elongate element is fixed to the pedal. 3. A mechanical means according to claim 1, characterised in that the inelastic flexible elongate element is fixed to the chassis. 4. A mechanical means according to claim 1, characterised in that pedal may move relative to the inelastic flexible elongate element which is fixed at both ends to the chassis. 5. A mechanical means according to any one of claims 1 to 3, characterised in that the inelastic flexible elongate element is selected from the group consisting of ropes, cords, wires and synthetic filaments. 6. A mechanical means according to claim 5, characterised in that the inelastic flexible elongate element is wound on a spool which is spring-loaded such that the elongate element " tends to be drawn back to the spool. 7. A mechanical means according to claim 4 characterised in that there is provided at the point of contact of the pedal and the inelastic flexible, elongate element a contact element 0 selected from the group consisting of lateral protrusions of the pedal, pulleys and curved shoes. 8. A mechanical means according to any one of claims 1-4, characterised in that the inelastic, flexible, elongate element is selected from the 5 group consisting of bicycle-type chains and toothed belts. 9. A mechanical means according to claim 8, characterised in that the inelastic, flexible, elongate element contacts the pedal by means of 0 a toothed sprocket or wheel rotatably mounted on the pedal. 10. A mechanical means according to any one of claims 1-4, characterised in that the reversible activatable movement-preventing means acts to 5 prevent directly linear movement of the inelastic flexible elongate element. 11. A mechanical means according to any one of claims 1-4, characterised in that the reversible activatable movement-preventing means acts to 0 prevent rotational movement of a rotatable component selected from the group consisting of toothed sprockets, toothed wheels and spools. 12. A mechanical means according to any one of claims 1-4, characterised in that the reversible 5 activatable movement-preventing means is electro¬ magnetic. 13. A mechanical means substantially as described with reference to the drawings.

Inventors: CAMM JAMES OWEN, CAMM, JAMES, OWEN
Applicants: CAMM JAMES OWEN, CAMM, JAMES, OWEN
Application year: 1985
Main classification: G05G5
IPC codes: B60T7, G05G5