GB2085993A - Mechanical remote control system for actuating a plurality of devices - Google Patents

Abstract

The specification describes a mechanical remote control system comprising interconnected Bowden mechanisms whereby a plurality of devices e.g. vehicle wheel brakes, can be operated by movement of a single actuator. In one four-wheel braking system the actuator (21) is connected by a tie (22) and a coupling device (25) to the conduit (23) of a first Bowden mechanism (24) having its core (29) common with that of a second Bowden mechanism (30) whose conduit is secured to a fixture (39). A pull force exerted on tie (22) by the actuator (21) tensions the core (29) of the two Bowden mechanisms thereby actuating two brakes (31, 32) and at the same time axially loading the conduits of those mechanisms and thereby causing simultaneous actuation of the other two brakes (36, 38) which are connected to those conduits by coupling devices (33, 34) and ties (35, 37). <IMAGE>

Description

SPECIFICATION Mechanical remote control system for actuating a plurality of devices This invention relates to mechanical remote control systems whereby movement can be simultaneously transmitted to a plurality of devices by movement of a common actuator, e.g.

a hand-lever.

Such systems are employed in certain vehicles for operating different wheel brakes responsive to operation of a hand-brake lever (see e.g. British Patent 1 467 679).

In some prior proposals Bowden mechanisms are employed so that actuating forces can be transmitted along non-rectilinear paths without using sheaves or other devices for imposing directional changes on connecting cables.

In the previously proposed systems employing Bowden mechanisms for operating opposed vehicle wheel brakes, the inner member (hereafter called "the core") of a Bowden mechanism transmits a pull-load to the operating lever of one of the brakes and the reaction force on the outer member (hereafter called "the conduit") of such mechanism exerts a thrust on a displaceable coupling device which is located between the two vehicle wheels and is connected to the operating lever of the other brake (see e.g. British Patent 1 464 967).

The present invention enables various advantages to be achieved in comparison with the known systems. One advantage is a greater flexibility in the choice of the lay-out of the force transmitting components. Another potential advantage is that it is easily possible to apply the invention for simultaneously operating more than two devices by the common actuator and with a high degree of efficiency.

The invention can be applied with particular advantage in a four-wheel braking system.

According to the present invention there is provided a mechanical remote control system for simultaneously actuating at least two parts from an actuator, e.g. a hand-lever, using interconnected Bowden mechanisms whose cores are connected to said actuatable parts, characterised in that the actuator is connected to an end portion of a Bowden mechanism conduit so that an actuating force on said actuator pulls said conduit end portion towards the actuator and thereby imposes on said cores tensile forces causing simultaneous operation of said actuatable parts.

The versatility of the invention in regard to the choice of system lay-out can be illustrated by considering by way of example the case where the invention is employed in a vehicle for actuating two opposed wheel brakes. In contrast to the prior art systems, it is not necessary for a coupling device for coupling two Bowden mechanisms together to be located between the two wheels.

Another important point, is that by using the invention the brakes of two independently suspended wheels can be actuated using only two Bowden mechanisms whereas three such mechanisms are required for that purpose when using the previously known system.

The force transmitted to each brake unit or other actuatable device can be equal to the input force transmitted from the actuator minus a loss factor which depends on the efficiency of the Bowden mechanisms.

The term "Bowden mechanism" as used in this specification includes any flexible mechanical remote control mechanism comprising an inner member (the core) which is longitudinally displaceable within a guiding casing (the conduit).

The term therefore includes mechanisms wherein the core, for example a flexible wire or cable, slides in contact with the conduit or a conduit liner, and mechanisms wherein the core is supported within the conduit by caged bearings. In the latter form of mechanism the core can be in the form of a flexible strip.

In preferred embodiments of the invention the system is characterised in that at least one of the Bowden mechanism conduits is held so that its end remote from the corresponding actuatable part is free for axial displacement responsive to tensile force on the associated core; the Bowden mechanisms are interconnected by means comprising one or more coupling devices connecting the core or a displaceable conduit end of one Bowden mechanism to the displaceable conduit end of another such mechanism; and the actuator is connected to at least one displaceable conduit end; whereby an input force causing displacement of the actuator results in balanced tensile forces on the cores causing simultaneous actuation of said parts.

The invention can be embodied in a braking system for simultaneously operating the brakes of two, four or even more independently suspended wheels, with use of only a single abutment, extraneous to the brake units, for sustaining the reaction force on the system.

The invention includes a four-wheel braking system wherein an actuator controls the brakes via a combination of Bowden mechanisms interconnected so as to co-operate in transmitting balanced forces to the four wheel-brakes, substantially as illustrated by Fig. 1 of the accompanying drawings. An important feature of that and various other systems according to the invention is the interconnection of two or more Bowden mechanisms so that a pull load on the core of one Bowden mechanism is transmitted to the conduit of another such mechanism.

For operating four independent brakes or other devices simultaneously, the system can comprise four Bowden mechanisms and two or three coupling devices, as will hereafter be exemplified.

In preferred embodiments, the actuator is connected to the displaceable conduit end portion of a first Bowden mechanism connected to one brake unit or other actuatable device; the core of that first mechanism is connected to the conduit of a second Bowden mechanism connected to a second said device, so that a tensile load is imposed on the core of that second mechanism when an actuating force is applied to the system via the actuator; the core of that second mechanism is connected to or forms an extension of the core of a third Bowden mechanism for actuating a third actuatable device; whereas a displaceable conduit end portion of that third mechanism is connected to the core of a fourth Bowden mechanism for actuating a fourth said device.

Certain embodiments of the invention, selected by way of example, are illustrated in the accompanying diagrammatic drawings comprising Figures 1 to 5 which show five different systems.

The system shown in Fig. 1 is effective for actuating four brake units 1, 2, 3 and 4 of independently suspended vehicle wheels by force transmitted from a pivoted hand lever 5. The system comprises effectively four Bowden mechanisms 6, 7, 8 and 9, although the mechanisms 7 and 8 can have a common core rather than different core members which are joined end to end. The outer ends of the cores of the four Bowden mechanisms are connected to brake levers within the units 1-4, and the corresponding ends of the conduits of those mechanisms are secured to the housings of the brake units.

The inner end of the core 10 of Bowden mechanism 6 is connected to the inner end of the conduit of Bowden mechanism 7 by a coupling device 11. That coupling device may be in the form of a box shackle or clevis comprising spaced side pieces between which the end portion of that conduit intrudes and which are joined by a transverse end piece in which the conduit end is secured. A similar form of coupling device is shown in British Patent No. 1 464 967.

The core of Bowden mechanism 7 is connected to or forms an extension of the core of Bowden mechanism 8. The inner end of the conduit of mechanism 8 is connected by another coupling device 12 similar to coupling device 1 to the core of the Bowden mechanism 9. The inner end of the conduit of that mechanism is secured to a fixture 13 which is the sole abutment, extraneous to the brake units, for sustaining reaction force on the system when the input force is applied via the hand-lever 5.

The hand-iever 5 is connected via a tie 14 and a coupling device 15 with the inner end of the conduit of Bowden mechanism 6.

When the lever 5 is pivoted to apply the brakes, the tie 14 pulls the coupling device 15 towards the lever. In consequence of the accompanying displacement of the inner end of the conduit of Bowden mechanism 6 tension is applied to the core of that mechanism which causes a displacement force to be transmitted to the inner end of the conduit of Bowden mechanism 7 via the coupling device 11 and this imposes tension on the core(s) of the mechanisms 7 and 8. This tension results in displacement of the inner end of the conduit of Bowden mechanism 8 towards the hand-lever 5, whereby tension is applied to the core of Bowden mechanism 9 via the coupling device 12.

The result is that the four brake units are operated simultaneously under balanced forces.

Each of the four output forces, applied to a brake unit, is a large percentage of the input force applied to tie 14. The sum of the four output forces is in excess of three times said input force.

A single adjustment means will suffice to adjust the entire system. For example, such an adjustment may be provided for altering the position of the inner end of the conduit of Bowden mechanism 9 in relation to the fixture 13. The adjustment facility may take the form of adjustment nuts screwed onto a threaded tubular end fitting on said conduit. As an alternative the flexible conduit of Bowden mechanism 9 can be formed to provide an external screw profile and an adjustment nut or nuts can be screwed directly onto such conduit. For example, the conduit may be formed in any of the ways described in British Patent 1 409 526.

Instead of the illustrated coupling devices, coupling devices can be used which form passageways through which the different Bowden conduits extend, as described in our International Patent Application No. filed on the same date as the present application, for an invention entitled "Mechanical Remote Control Assemblies".

Fig. 2 shows a two-wheel braking system. This corresponds with part of the Fig. 1 system and corresponding parts in the two figures are denoted by the same reference numerals. The corresponding Fig. 2 numerals however carry the index "'". In the Fig. 2 system the inner end of the core of Bowden mechanism 71 is secured to a fixture 1 6. An input force on the tie 14' by operation of the hand-brake lever 51 results in balanced output forces on the two brake units, the sum of the output forces being nearly twice said input force.

Fig. 3 shows a possible modification of the system shown in Fig. 2. According to this modification the inner end of the conduit of Bowden mechanism 61 is connected to the conduit of Bowden mechanism 71 by a coupling device 17 and the inner ends of the cores of the two Bowden mechanisms are secured to the fixture 161. The coupling device 17 is directly connected to the hand-brake lever (not shown in Fig. 3) by a tie 18. A pull force on that tie causes displacements of the inner ends of the conduits of the two mechanisms and consequently imposes tensile forces on their cores whereby both brake units are operated under balanced forces.

Fig. 4 represents a four-wheel braking system of a vehicle with rigid wheel axes. The system incorporates co-operating control assemblies according to the invention. A hand lever 21 is connected by a tie 22, for example a rod or a cable, to the conduit 23 of a Bowden mechanism 24. For the purpose of this connection a coupling device 25 is employed which as hereinbefore referred to forms a passageway through which the conduit 23 extends. The coupling device has been fastened to the conduit at a required position therealong so that the coupling device and conduit will move as a unit. This fastening is effected at the time when the control system is installed, choosing the most appropriate site for the coupling device. The length of the conduit 23 is not critical.Fastening of the coupling device to the conduit can be achieved in any suitable manner, for example in any of the ways herein specifically described, but preferably so that the position of the coupling device along the conduit can be easily varied at any time. In this instance the coupling device is secured in position by a clamping plug 26 which is forced into one end of the coupling device. The tie 22 is connected to a lug portion 27 of the coupling device at a point 28 which is in alignment with the axis of the remote end portion of the conduit passageway.

The inner member 29 of the Bowden mechanism 24 is common to that mechanism and a second Bowden mechanism 30. Opposed ends of that inner member 29 are connected to the brake levers 31, 32 of the front right-hand and the rear left-hand brake units.

The conduits of the Bowden mechanisms 24 and 30 pass through second and third coupling devices 33 and 34 respectively. These further coupling devices are of the same form as coupling device 25. Coupling device 33 is connected by means of a tie 35 with the brake lever 36 of the front left-hand brake unit. Coupling device 34 is connected by means of a tie 37 with the brake lever 38 of the rear right-hand brake unit.

The conduit of the Bowden mechanism 30 at its end remote from the coupling device 34 is secured-to a fixture 39. This connection can be achieved for example by means of clamping nuts screwed onto a threaded metal end fitting of the conduit as known per se. The fixture 39 is the only fixed anchorage for the brake system.

When the hand-brake lever 21 is moved to apply the brakes, the coupling device 25 is pulled towards such lever, thereby imposing a tensile load on the inner member 29 of the Bowden mechanisms 24 and 30. This tensile load is directly applied to the brake levers 31 and 32. The force transmitted to the conduit 33 of Bowden mechanism 34 via the tie 32 causes the front end portion of that conduit, together with the attached coupling device 33, to be displaced towards brake lever 31 and in consequence a similar operating load is transmitted to the brake lever 36 via the tie 35.The tensile load on the inner member 39 which causes displacement of brake levers 31 and 32, also causes the rear end portion of the conduit of the Bowden mechanism 30, together with the attached coupling device 34, to be displaced towards the brake lever 32 and in consequence a similar operating load is transmitted to the brake lever 38 via the tie 37. Spring means (not shown) is present which urges the control assembly towards its brake release position. Such spring means may comprise springs located within the brake units.

The system affords a remarkably high aggregate output force. The operating force on each of the brake units approaches a value equal to the force applied to the tie 22 via the hand brake lever 21, minus a loss factor which depends on the operating efficiencies of the Bowden mechanisms. The aggregate output force can be well in excess of three times the force applied to the tie 22. The four output forces are balanced, i.e.

equal to each other.

The operating efficiencies attained are in part attributable to the fact that the inner member 29 of the Bowden mechanisms is fully supported by the guiding conduits over the full lengths of the coupling devices 33 and 34. Another contributory factor is the location of the connecting points for the ties 22, 35 and 37 in alignment with the axes of the respective Bowden conduits where they emerge from the passageways in the coupling devices.

For the purpose of making in-service adjustments to the brake system, it suffices to provide a single adjustment facility. For this purpose the conduit of Bowden mechanism 30 can be provided with a threaded metal end fitting and adjustment nuts at the point where it is connected to the fixture 39. By manipulation of such nuts the curvatures and therefore the operations of the two Bowden mechanisms can be adjusted.

In preferred embodiments however an adjustment facility is provided directly on the flexible conduit of one of the Bowden mechanisms and use of the adjustment facility alters the position at which one of the coupling devices is secured to such conduit.

If it is required to operate only the two rear wheel brakes from the hand-lever 21, this can be done by omitting the Bowden mechanism 24, the coupling devices 25 and 33 and the tie 35, and connecting the inner member 29 of the Bowden mechanism 20 directly to the lever 21. In that case the projecting front end portion of such inner member takes the place of tie 22.

Fig. 5 shows a remote control system according to the invention installed for operating the brake units 40, 41 of opposed independently suspended vehicle wheels. The system empioys two Bowden mechanisms, 42, 43 and a single coupling device 44 with which an adjuster 45 is associated.

The inner member of the Bowden mechanism 42 is connected at its front end to the hand brake lever 21' and at its rear end to an operating lever within the brake unit 40. The rear end of the conduit of that mechanism is secured to the housing of the brake unit. The inner member 43' of the Bowden mechanism 43 connects the brake lever in brake unit 41 with the coupling device 44.

The conduit of that mechanism is secured at its rear end to the housing of brake unit 42 and at its front end to a fixture 46.

The conduit of the Bowden mechanism 42 comprises closely helically interwound wires which form at the exterior surface of the conduit a male screw and the adjuster 45 is in direct screw engagement with such male screw so that such adjuster can be screwed to any desired adjusted position along the conduit. The said conduit may for example have any of the forms described and shown in British Patent No. 1 409 526.

When a pull load is applied to the inner member of Bowden mechanism 42 via the lever 21 the front end portion of the conduit of that Bowden mechanism together with the coupling device 44 is displaced towards the lever 21' and brake units 40 and 41 are operated simultaneously. The operating force on each unit is equal to the force applied to the inner member of the Bowden mechanism 42 minus a loss factor depending on the efficiency of the Bowden mechanisms. The two output forces are balanced.

The fact that the conduit of the Bowden mechanism 42 projects forwardly from the coupling device 44 contributes to the smooth and efficient operation of the system because this projecting portion of the conduit is free to flex responsive to the arcuate movements of the connecting point between the inner member of such mechanism and the lever 21 '.

Coupling devices forming curved passageways through which the conduits of Bowden mechanisms extend, like coupling devices 25, 33 and 34 in Fig. 4 and device 44 in Fig. 5 can be arranged as indicated to be connectable to such conduits over a range of different positions therealong. This is an advantage in setting up the systems in a given space envelope. Coupling devices formed in that way can be used in systems as shown in Figs. 1 and 2, in place of the coupling devices 11, 12, 15 and 151 therein shown.

Claims (8)

1. A mechanical remote control system for simultaneously actuating at least two parts from an actuator, e.g. a hand-lever, using interconnected Bowden mechanisms whose cores are connected to said actuatable parts, characterised in that the actuator is connected to an end portion of a Bowden mechanism conduit so that an actuating force on said actuator pulls said conduit end portion towards the actuator and thereby imposes on said cores tensile forces causing simultaneous operation of said actuatable parts.

2. A remote control system according to claim 1, wherein at least one of the Bowden mechanism conduits is held so that its end remote from the corresponding actuatable part is free for axial displacement responsive to tensile force on the associated core; the Bowden mechanisms are interconnected by means comprising one or more coupling devices connecting the core of a displaceable conduit end of one Bowden mechanism to the displaceable conduit end of another such mechanism; and the actuator is connected to at least one displaceabie conduit end; whereby an input force causing displacement of the actuator results in balanced tensile forces on the cores causing simultaneous actuation of said parts.

3. A remote control system according to claim 1 or 2, wherein two or more Bowden mechanisms are inter-connected so that a pull load on the core of one Bowden mechanism is transmitted to the conduit of another such mechanism.

4. A remote control system according to any preceding claim wherein the actuator is connected to the displaceable conduit end portion of a first Bowden mechanism connected to one actuatable device; the core of that first mechanism is connected to the conduit of a second Bowden mechanism connected to a second said device, so that a tensile load is imposed on the core of that second mechanism when an actuating force is applied to the system via the actuator; the core of that second mechanism is connected to or forms an extension of the core of a third Bowden mechanism for actuating a third actuatable device; whereas a displaceable conduit end portion of that third mechanism is connected to the core of a fourth Bowden mechanism for actuating a fourth said device.

5. A remote control system according to any preceding claim, wherein the actuator is connected to an end portion of the conduit of a first Bowden mechanism whose core is an extension of or is connected to the core of a second Bowden mechanism; the remote ends of said core or said conjoined cores are connected to two devices to be actuated; and the remote end portions of the conduits of said first and second Bowden mechanisms are connected by ties to third and fourth devices to be actuated.

6. A remote control system according to any preceding claim being a four-wheel braking system for operating four vehicle brakes simultaneously by movement of said actuator.

7. A remote control system according to claims 5 and 6 and substantially as illustrated by Fig. 1 of the accompanying drawings.

8. A remote control system according to claims 5 and 6 and substantially as illustrated in Fig. 4 of the accompanying drawings.