GB2241050A

GB2241050A - Vehicle foot pedal mounting

Info

Publication number: GB2241050A
Application number: GB9003432A
Authority: GB
Inventors: William Carl Baskett
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1990-02-15
Filing date: 1990-02-15
Publication date: 1991-08-21
Also published as: GB9003432D0

Abstract

The weight of the pedal (26,28) is supported by an actuating rod (20) for the component, eg brake booster (12), to be operated by the foot pedal. The pedal is also connected to a spring plate (34) which is attached to the bulkhead (10) and which determines the arc of movement through which the pedal will move on actuation, and provides a restoring force to return the pedal to its starting position. The use of a flexible mounting plate (34) enables improvement of crash performance criteria. <IMAGE>

Description

FOOT PEDAL ARRANGEMENT This invention relates to the arrangement of a foot pedal, for example the brake pedal in a motor vehicle. The invention is particularly, but not exclusively, concerned with the mounting of pedals which are directly connected to an actuating rod. For example, the pedal may operate a hydraulic or pneumatic piston rod.

In a car, the mountings for the foot pedals are arranged in front of the driver. As such, the design of the pedals and what happens to them in the event of a front end impact is of considerable importance because the crash performance of motor vehicles is strictly evaluated.

Driver requirements, that is the perceived "feel" of the pedal operation, also determine a specific required arc of movement for the pedal, and this sets the position at which the hinge axis for the pedal must be set. This position is between the front bulkhead of the passenger compartment and the position of the driver.

It is conventional to provide a rigid support structure mounted in the passenger compartment, on the front bulkhead, to provide a support for the pedal hinge axis.

The presence of this support structure however has an adverse effect on crash performance.

According to the present invention, there is provided a foot pedal arrangement for a motor vehicle, the arrangement comprising a pedal pad mounted on the end of a pedal shank, an actuating rod pivotally connected to a point on the shank and adapted to be moved in an actuating direction when the pedal pad is pressed, the rod being arranged to support the weight of the pedal pad and shank, and a pedal hinge in the form of a flexible plate which connects the shank to a point on the vehicle bodywork so as to provide both a restraint to the movement of the shank when the pedal pad is pressed, and a restoring force to restore the shank to a rest position.

The transfer of the pedal supporting function from the pedal hinge to the actuating rod makes it possible to construct the hinge in a very different manner. The use of a flexible plate which can bend or buckle under the loads experienced in a crash means that the crash performance criteria are considerably improved.

The actuating rod is preferably a push rod guided in slide bearings, the bearings being constructed so as to support the weight of the pedal pad and shank. In a preferred embodiment, the pedal is a brake pedal and the actuating rod is part of a brake servo mechanism.

The flexible plate is preferably made from spring steel and is mounted generally horizontally so that when the pedal pad is pressed, a tension force is set up lying generally in the plane of the plate to restrain the movement of the plate. The plate is also preferably rigidly connected to the pedal shank, so that as the angle of the pedal shank changes as the pad is pressed, the plate is caused to flex in the manner of a leaf spring, and a restoring force is generated which acts to restore the shank to its rest position when the pedal pad is released.

Conveniently the plate can be connected between the vehicle bodywork and a top end of the shank, with the actuating rod connected to a point on the shank which is between the top end and the bottom end where the pedal pad is fitted.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a foot pedal arrangement in accordance with the invention; and Figure 2 is a sectional view of the arrangement of Figure 1.

Figure 1 shows a bulkhead or dash panel 10 which provides a forward boundary to the passenger compartment of a vehicle separating the passenger compartment from the front end of the vehicle. Various components extend through this bulkhead such as the steering column and the speedometer cable, as well as the components which are operated by foot pedals and which themselves control the running of the vehicle.

The invention is described here in relation to a footoperated brake pedal which itself operates a brake booster or servo 12 (see Figure 2). The servo has a housing 14 which is bolted to the rear side of the bulkhead 10 by means of fastenings 16, and has a collar 18 projecting through the bulkhead. A push rod 20 slides in bearings 22,24 within the housing 14. The bearings form guides for backwards and forwards axial sliding movement of the rod 20. The internal components of the servo or booster 12 form no part of this invention, and for this reason they are not shown in the drawing. The servo will however be operated in a conventional manner by axial movement of the rod 20.

The brake pedal itself comprises a pedal shaft 26 and a pedal pad 28 fitted at one end of the shaft. The shaft will be formed in a conventional manner as a channel section, and the pad 28 will be fitted at one end as is known. The pad comprises an area where a drivers foot can engage with the pedal, and the construction of the pad itself is not important.

The outermost end of the push rod 20 is provided with a cylindrical hole at right angles to its length, and a bolt 30 with a nut 32 passes through holes in the side walls of the pedal shank 26 and through the cylindrical hole in the end of the push rod 20.

The diameter of the push rod 20 and the capablility of the bearings 22,24 are such as to be capable of supporting the weight of the pedal shank 26 and pad 28.

At its top end, the shank 26 is secured to a spring plate 34 which acts like a leaf spring. The outer end of the plate 34 is bent over at 36 and is secured to the top of the shank 26 by two rivets 38. The plate 34 is secured at its opposite end through an integral flange 40 to the bulkhead 10 by means of bolts 42,44. The bolts 42 and 44 are spaced further apart than the rivets 38, to help to prevent any lateral movement of the pedal.

In use, when the pedal is depressed as shown in Figure 3, the push rod 20 will be guided along its axis by the bearings 22 and 24 and will control the vertical position of the pedal. The spring plate 34 will take up a bowed position as shown in Figure 3, and in doing so will store energy, and will also determine the arc in which the pedal pad 28 will move. This arc is important in providing the correct "feel" for the driver.

Because of the resistance to pushing motion which will be provided by the rod 20, the pedal will act as a lever pivoting about the bolt 30, and the plate 34 will be put into tension. This tension will prevent excessive displacement of the top of the shank 26, so that the arc of movement of the pad will be repeatable. However the internal spring energy stored by the plate when it deforms to the condition shown in Figure 3 will be released when the driver lifts his foot from the pedal, and this spring energy will provide a restoring force to return the pedal to its initial rest position where the spring is in a substantially flat state. Even in this rest state however there should be some residual spring energy stored by the plate to ensure that the pedal is urged right up to its limit position, and to prevent any free play or rattling of the pedal.

Because the plate 34 only needs to act in tension and in bending, it does not need to be very substantial and it can be constructed so that it will easily be bent, buckled or deflected in the event of a crash to avoid injury to the occupants of the vehicle.

Claims

1. A foot pedal arrangement for a motor vehicle, the arrangement comprising a pedal pad mounted on the end of a pedal shank, an actuating rod pivotally connected to a point on the shank and adapted to be moved in an actuating direction when the pedal pad is pressed, the rod being arranged to support the weight of the pedal pad and shank, and a pedal hinge in the form of a flexible plate which connects the shank to a point on the vehicle bodywork so as to provide both a restraint to the movement of the shank when the pedal pad is pressed, and a restoring force to restore the shank to a rest position.

2. An arrangement as claimed in Claim 1, wherein the actuating rod is a push rod guided in slide bearings, the bearings being constructed so as to support the weight of the pedal pad and shank.

3. An arrangement as claimed in Claim 2, wherein the pedal is a brake pedal and the actuating rod is part of a brake servo mechanism.

4. An arrangement as claimed in any preceding claim, wherein the flexible plate is made from spring steel and is mounted generally horizontally so that when the pedal pad is pressed, a tension force is set up lying generally in the plane of the plate to restrain the movement of the plate.

5. An arrangement as claimed in any preceding claim, wherein the plate is rigidly connected to the pedal shank, so that as the angle of the pedal shank changes as the pad is pressed, the plate is caused to flex in the manner of a leaf spring, and a restoring force is generated which acts to restore the shank to its rest position when the pedal pad is released.

6. An arrangement as claimed in any preceding claim, wherein the plate is connected between the vehicle bodywork and a top end of the shank, with the actuating rod connected to a point on the shank which is between the top end and the bottom end where the pedal pad is fitted.

7. A foot pedal arrangement, substantially as herein described with reference to the accompanying drawings