PEDAL OPERATING MECHANISMS

Abstract: A pedal operating mechanism (10) particularly for the operation of vehicle brake or clutch master cylinders (14, 15) having a mounting bracket (11), a pedal (12) pivotally mounted on the bracket via a pivot pin (13) and an actuation linkage (16) for operatively connecting the pedal to the master cylinder(s). The pivot (13) is adjustably mounted (31, 32) on the bracket (11) so that the operating ratio of the pedal is adjustable. This adjustement may be made by operation of an adjustment means sited remote from the pedal.

Description: PEDAL OPERATING MECHANISMS This invention relates to pedal operating mechanisms and in particular, though not exclusively, to such mechanisms for operating master cylinders for vehicle brakes and/or clutches. It is an object of the present invention to provide an improved form of pedal operating mechanism which allows easy tuning of the mechanism to a wide range of driver/vehicle requirements. Thus according to the present invention there is provided a pedal operating mechanism comprising a mounting bracket, a pedal pivotally mounted on the bracket via a pivot pin, and an actuation linkage for operatively connecting the pedal to a device to be operated, the mechanism being characterised in that the pivot is adjustably mounted on the bracket so that the operating ratio of the pedal is adjustable. Such an arrangement allows easy adjustability of the operatin ratio mechanism (that is the angular displacement of the peda to achieve a given movement of the actuation linkage) to cate for individual driver requirements/preferences. This is particularly useful in competition vehicles. The pivot may be adjustable in a first guide means in one of the pedal or bracket, the pivot also moving along a second guide means in the other of the pedal or bracket during such adjustment, and control means may be provided for preventing movement of the pivot along the second guide means during pivoting of the pedal relative to the bracket. The control means may comprise slot means in one of the bracket or pedal engaged by a locating formation on the othe of the bracket or pedal which moves along the slot means during pivoting of the pedal. In one form the bracket may have two limbs between which the pedal is pivotally mounted and the first guide means may be provided in the pedal in the form of a first slot along whic the pivot is adjustable, the second guide means comprising a pair of second slots one in each limb of the bracket which receive the ends of the pivot. Preferably adjustment of the pivot relative to the bracket i achieved by rotation of an adjustment member which is in screw-threaded engagement with the pivot. The adjustment member may be rotated by an adjustment linkag which is operable at a location remote from the pedal. This enables the driver to change the operative ratio of the peda mechanism during use of the vehicle. Alternatively the adjustment member may be provided with a turning formation for direct manual rotation and locking means may be provided to hold the adjustment member in a fixed rotational position during pivoting of the pedal. The pedal operating mechanism is particularly suitable for the operation of brake or clutch master cylinders. In brake applications the actuating linkage may be connected to two master cylinders for their simultaneous operation. In such an arrangement the linkage may include a "balance bar" connection which allows adjustment of the relative level of actuation of the two master cylinders on each operation of the pedal. In alternative uses the pedal may be connected to the device to operate by an actuation linkage in the form of a cable to operate, for example, a vehicle clutch. One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of a master cylinder pedal operating mechanism embodying the present invention; Figure 2 is a plan view of the mechanism of figure 1; Figure 3 is an end view in the direction of arrow A of figure 1; Figures 4 and 5 show parts of figures 1 and 3 respectively on an enlarged scale for clarity, and Figure 6 shows details of the pivot adjustment at the bottom of the pedal of the mechanism of figure 1. Referring to figures 1,2 and 3 the master cylinder pedal operating mechanism 10 comprises a floor mounted mounting bracket 11 on which a pedal 12 is pivotally mounted by a pivot pin 13 (see figures 5 and 6). Pedal 12 is connected with two master cylinders 14,15 via an actuation linkage 16 which includes master cylinder operating rods 14a and 15a and an adjustable balance bar 17 which is operatively connected with rods 14a and 15a via screw thread connections 14b and 15b in yokes 14c and 15c which are operatively connected with rods 14a and 15a respectfully. Balance bar 17 is connected with pedal 12 via a spherical bearing 18 (see dotted detail in figure 3 and detail in Figure 5) which is slideable within a bore 19 in the pedal. As will be appreciated from figure 3, rotation of the balance bar 17 about its longitudinal axis B causes axial displacement of the bar and bearing 18 within bore 19 by virtue of the screw-threaded engagements 14b and 15b of the balance bar with the yokes 14c and 15c respectively. Thus the ratio of the distances x and y between the effective plane of action of pedal 12 and the operating rods 14a and 15a of cylinders 14 and 15 can be adjusted from a central position (shown in figure 3) in which the distances x and y are equal (when both cylinders 14 and 15 receive equal actuating movement) to positions either side of this central position in which one or other of the master cylinders receives more or less actuating movement for a given pedal displacement. In this manner, for example, if master cylinder 14 is controlling the front brakes of a vehicle and master cylinder 15 the rear brakes the balance of braking between the front and the rear of the vehicle can be adjusted by rotation of balance bar 17. Balance bar 17 is arranged to be rotatable by a cable 20 one end of which rotates balance bar 17 and the other end of which terminates in a knob mounted on a dashboard of the vehicle. Thus the vehicle driver is able to adjust the balance of front to rear braking of the vehicle whilst the vehicle is in motion. It will also be apparent that the fully released position of pedal 12 (shown in full lines in Figure 1) can be adjusted, to take account of leg length variations etc. of different drivers, by virtue of the screw-threaded attachment of yokes 14c and 15c with cylinder operating rods 14a and 15a. In accordance with the present invention the position of the pivot pin 13 of pedal 12 is adjustable relative to bracket 11 so that the operative ratio of the pedal 12 can be adjusted to give more or less travel of the pedal for a given level of master cylinder operation dependent on the pedal operating characteristics which the vehicle driver wishes to achieve. As can be seen from figure 6, the pivot pin 13 is mounted in a first guide means in the form of a slot 21 formed in the bottom portion of the pedal 12. Pin 13 is movable within slot 21 by an adjustment member in the form of a bolt 22 which extends within a bore 23 in the pedal 12 and is held in the bore by a circlip 24 which engages a flange 25 on the bolt. Bolt 22 is provided with a screw threaded portion 26 which engages a screw threaded cross bore 27 in pivot 13. Thus rotation of bolt 22 in bore 23 displaces pivot 13 along slot 21. The head of bolt 22 is provided with a blind bore 28 into which an end of an operating cable 29 is inserted and retained by a grub screw 30. The other end of cable 29 terminates in a knob mounted remotely on the vehicle dashboard thus enabling the operator to rotate cable 29 and hence move pivot 13 up and down slot 21. Alternatively rotation of cable 29 could be accomplished by an electric motor or other power-operated means under the control of the driver or a computerised brake controller. The ends 13a and 13b and pivot 13 carry sliding blocks 31 (see figure 5) which move up and down slots 32 provided in limbs 33 of bracket 11. Thus as pivot pin 13 is moved up and down slot 21 by rotation of cable 29 the sliding blocks 31 move up and down slots 32 in limbs 33 of bracket 11. In order to prevent sliding blocks 31 moving up and down slots 32 during pivoting of pedal 12 relative to bracket 11 (which would also result in pedal 12 sliding up and down) a control means is provided in the form of a second pin 35 which extends through a bore 36 in the pedal 12 and carries on its ends sliding blocks 37 which are engaged in generally horizontal slots 38 cut in the limbs 33 of the bracket 11. Circlips 39 axially locate the second pin 35 relative to the pedal 12. As will be appreciated, when the pedal 12 pivots relative to the bracket 11 about the position currently occupied by pivot pin 13 the second pin 35 and associated sliding blocks 37 move along the slots 38 and thus prevent the sliding blocks 31 moving along the slots 32 in the limbs 33 and ensuring the correct pivoting of pedal 12. It will be apparent from the above that by adjustment of the position of pivot pin 13 within slot 21 and slots 32 the effective pivot point of the pedal 12 can be adjusted relative to the bracket 11 so that the operating ratio of the pedal mechanism is variable. As pivot pin 13 is moved up slot 21 (as viewed in Figure 6) the perpendicular distance between pivot pin 13 and the line of action of cylinder operating rods 14a and 15a is reduced so that a larger amount of angular movement of pedal 12 becomes necessary to achieve a given movement of rods 14a and 15a . Thus by moving pivot 13 the operating characteristics of pedal 12 can be varied to suit the vehicle driver. This is particularly useful in competition vehicles. Since the cable 29 is operable from the vehicle dashboard th operating ratio of the pedal mechanism can again be adjusted whilst the vehicle is in motion. It will be appreciated tha friction associated with the rotation of cable 29, or a detent mechanism on the cable, holds bolt 22 in its adjusted position preventing movement of pivot 13, during use of pedal 12. In an alternative arrangement the cable 29 is not provided and the bolt 22 is directly mechanically rotated by, for example, an Allen key engaging in blind bore 28. A locking arrangement (not shown) is also provided. For example, a grub screw of some other method of locking the bolt 22 withi bore 23 once the desired position of pivot pin 13 within slo 21 has been obtained. Also, although the pedal operating mechanism has been described above in relation to the operation of two brake cylinders it will be appreciated that the mechanism could equally well be used to operate a one master cylinder (which could be a tandem master cylinder) for operation of vehicle brakes and for the operation of a vehicle clutch. Thus in a given vehicle both the brake pedal operating mechanism and the clutch pedal operating mechanism could be provided with adjustable pivots in accordance with the present invention. Again, although the invention has been illustrated with reference to a floor mounted pedal operating mechanism it will be appreciated that a top-mounted pedal arrangement could be employed (basically simply achieved by inverting the arrangement shown in the accompanying drawings) in which the pedal is pivoted below the bracket. Further, it will be appreciated that the adjustable pivot of the pedal operating mechanism of the present invention has a wide application and is applicable, for example, to pedals in which the actuation linkage comprises a cable which connects the pedal to a device to be operated such as a vehicle clutch.

Claims: CLAIMS A pedal operating mechanism (10) comprising a mounting bracket (11), a pedal (12) pivotally mounted on the bracket via a pivot pin (13) and an actuation linkage (16) for operatively connecting the pedal to a device (14,15) to be operated, the mechanism being characterised in that the pivot (13) is adjustably mounted (31,32) on the bracket (11) so that the operating ratio of the pedal is adjustable. A mechanism according to claim 1 characterised in that pivot (13) is adjustable in a first guide means (21) one of the pedal (12) or bracket (11), the pivot also moving along a second guide means (32) in the other o the pedal or bracket during such adjustment, and cont means (35-38) are provided for preventing movement of the pivot (13) along the second guide means (32) durin pivoting of the pedal relative to the bracket. A mechanism according to claim 2 characterised in that the control means comprises slot means (38) on one of the bracket (11) or pedal (12) engaged by a locating formation (37) on the other of the bracket or pedal which moves along the slot means during pivoting of th pedal. 4. A mechanism according to claim 2 to 3 characterised in that the bracket (11) has two limbs (33) between which the pedal (12) is pivotally mounted and the first guide means (21) is provided in the pedal in the form of a first slot (21) along which the pivot (13) is adjustable, the second guide means comprising a pair of second slots (32) one in each limb (33) of the bracket which receive the ends of the pivot (13). 5. A mechanism according to claim 5 characterised in that each end of the pivot (13) is received in a block (31) which slides in the associated second slot (32). 6. A mechanism according to any one of claims 1 to 5 characterised in that the adjustment of the pivot (13) relative to the bracket (11) is achieved by rotation of an adjustment member (22) which is in screw-threaded engagement (23) with the pivot. 7. A mechanism according to claims 2 and 6 characterised in that the pivot (13) moves along first guide means (21) in the form of a first slot (21) in the pedal on rotation of the adjustment member. 8. A mechanism according to claim 6 or 7 characterised in that the adjustment member (22) is rotatable by a adjustment linkage (29) operable at a location remote from the pedal (12). 9. A mechanism according to claim 8 characterised in that the adjustment linkage comprises a cable (29)one end of which is connected with the adjustment member (22) and the other end of which is sited remote from the pedal (12) and is rotatable by hand or power-operated means. 10. A mechanism according to claim 6 or 7 characterised in that the adjustment member (22) is provided with a turning formation for direct manual rotation and locking means are provided to hold the adjustment member in a fixed rotational position during pivoting of the pedal. 11. A mechanism according to any one of claims 1 to 10 characterised in that the actuation linkage (16) is connected to a master cylinder (14,15). 12. A mechanism according to claim 11 characterised in that the actuation linkage (16) is connected to two master cylinders (14,15) for their simultaneous operation. 13. A mechanism according to claim 12 characterised in that the actuation linkage (16) includes a "balance bar" connection (17) which allows adjustment of the relative level (x,y) of actuation of the two master cylinders (14,15) on each operation of the pedal (12). 14. A mechanism according to any one of claims 11 to 13 characterised in that the or each associated master cylinder (14,15) is also mounted on the bracket (11). 15. A mechanism according to any one of claims l to 10 characterised in that the actuation linkage comprises a cable connecting the pedal with the device to be operated. 16. A mechanism according to any one of claims 1 to 15 characterised in that the bracket (11) is designed to support the pedal (12) with the pivot pin (13) below the point of application of force to the pedal by an operator. 17. A mechanism according to any one of claims 1 to 15 characterised in that the bracket is designed to support the pedal with the pivot pin above the point of application of force to the pedal by an operator. 18. A pedal operating mechanism constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Inventors: BASS ARNOLD RICHARD, GENON PIERRE-YVES, BASS, ARNOLD, RICHARD, GENON, PIERRE-YVES
Applicants: AUTOMOTIVE PRODUCTS PLC, BASS ARNOLD RICHARD, GENON PIERRE YVES, BASS, ARNOLD, RICHARD, GENON, PIERRE-YVES
Application year: 1996
Main classification: G05G1
IPC codes: B60T7, B60T11, G05G1