GB2488523A

GB2488523A - Brake locking mechanism having a locking member that pivots in an axis perpendicular to the pivot axis of the brake actuation means

Info

Publication number: GB2488523A
Application number: GB201102757A
Authority: GB
Inventors: Geoffrey Kenneth Berrisford
Original assignee: MOUNTAIN TRIKE Co Ltd
Current assignee: MOUNTAIN TRIKE Co Ltd
Priority date: 2011-02-17
Filing date: 2011-02-17
Publication date: 2012-09-05
Anticipated expiration: 2031-02-17
Also published as: GB2488523B; GB201102757D0

Abstract

A wheelchair brake locking mechanism comprises a locking member 7 able to rotate about an axis 5, 15 perpendicular to the pivot axis of the brake activation means 6, to apply the parking brake of the wheel chair. Increased rotation of the locking member 7 effects increased compression of the brake actuation means 6 (figure 7). This is particularly applicable to a wheelchair for travel over rough terrain whereby movement of the vehicle is effected by the power of the arms. The brake may be actuated by a cable or by hydraulics and is preferably a disc brake (13, figs 1 & 4).

Description

Wheelchair parking brake This invention relates to a device that enables users to travel over rough terrain whilst seated and whereby movement of the vehicle is effected by the power of the arms. The device features a parking brake to limit movement of the device allowing the User who may have disabilities in their movement to transfer into the device and when the User wishes to remain stationary to rest.

Traditional wheelchair brakes are limited to providing the function of locking the wheels to prevent the Wheelchair rolling when parked, by pressing a lever arm directly onto the tyre to prevent rotation. However they can be difficult to apply and are ineffective when the tyres wear or if conditions are wet and slippy as they may not lock the wheels effectively.

The invention aims to overcome these shortcomings by providing improved braking performance in general operation and a highly effective means of locking the brakes on when parked which is immune to weather conditions or wear of parts. The system can be fitted to wheelchairs in various ways including new propulsion lever drive wheelchairs and traditional arrangements.

The braking means is preferably provided by a disc brake mounted at the hub of the ground contacting wheel and a hand operated brake lever mounted on the propulsion lever. Disc brakes are highly effective means of applying braking force to the wheels of the device even in wet weather conditions.

However, the braking means may also be provided by a rim brake or drum brake and the lever could be mounted on the frame or other points on the wheelchair. Brake levers are sprung such that they automatically release when the User releases pressure on the lever, thus allowing it to return to its released position. Therefore, to achieve the means of maintaining application of the brake when the User is not holding the brake lever during transfer into the device or if the User requires to remain stationary and have free use of their hands to carry out other tasks or rest, a means of locking the brakes on in their fully applied position is required.

The invention will now be described solely by way of example with reference to the accompanying drawings in which: Figure 1 shows the overall preferred layout of the device and optimum position of the parking brake levers Figure 2 shows the arrangement of the parking brake unit packaged with the drive system Figure 3 shows the arrangement of the parking brake packaged with the brake lever Figure 4 shows an alternative mounting arrangement of the parking brake lever Figure 5 shows the parking brake in its released state Figure 6 shows the parking brake in its engaged state where the brake is locked on In Figure 1, the wheelchair features front wheels number 1 which are of larger diameter than the rear steering wheel number 2. The front wheels number I are driven via a propulsion mechanism consisting of a chain 1, input sprocket 3 and output sprocket 4 and a propulsion lever 5 including a freewheel element allowing the device to travel without causing the propulsion lever to rotate. Propulsion Lever 5 supports the brake lever 6 and parking brake 7, positioned by handgrip 8. The propulsion system is supported by a swing arm member 9 which is freely hinged at its upper end and carries the ground contacting wheel and axis at its lower end. The swing arm supports the disc brake calliper 10 which acts on disc brake rotor 13 that mounts to front wheel 1. The swing arm 7 and propulsion lever 5 both pivot about the same point such that the propulsion system and braking system are unaffected by vertical displacement of the ground contacting wheel. A sprung suspension strut 11 and the swing arm 7 is connected to main frame 12 thus allowing vertical displacement of the ground contacting wheel.

Figure 2 shows the right and left Propulsion levers 5 and 15 which allow drive to be applied independently to the right and left wheels. The steering lever 14 may be fitted to either the right or left propulsion lever depending on the preference of the user. The left and right brakes may also be operated independently of each other to allow effective manoeuvrability. A parking brake 7 is fitted to either left or right or both drive levers such that it is possible to lock the brakes on whilst being unaffected by movement of the propulsion levers or suspension systems.

Figure 3 shows the arrangement of the parking brake and brake lever in isometric view. The User holds handgrip 8 with their hand where brake lever is operated by pulling the lever with the User's fingers. Parking Brake 7 fits around Brake lever 6 such that it is also operable by the User's fingers. The grip, lever and parking brake mount to propulsion lever 5 and 15 such that drive, steering, braking and operation of the parking brake all take place at the same point using the User's hands.

Figure 4 shows an alternative arrangement where brake lever 6 and parking brake 7 are mounted to the frame of the device where disc calliper 10 acts on disc rotor 13 which is mounted to main drive wheel 1. This arrangement is not preferred as the brakes would be operated from a different point to that of the propulsion (the hand rim of drive wheel 1), therefore hindering overall control.

Figure 5 shows the parking brake 7 in its unlocked position, such that brake lever 6 is free to swing, thus allowing the User to apply the brake with appropriate force to achieve controlled speed reduction during riding. The position of the parking brake allows the brake lever to be released by the User once they have achieved the speed they wish to travel at. The brake lever is sprung such that it automatically releases in this state, returning to its released position.

Figure 6 shows the parking brake 7 in its locked position. The Parking brake is locked on when the device is stationary by first pulling brake lever 6 until the brake is fully applied, then rotating parking brake 7 until it contacts the brake lever, thus maintaining application of the brake even when the User lets go of the Parking brake by preventing the lever returning to its released position.

Figure 7 shows the operation of the parking brake such that it rotates around propulsion lever 5 and 15 and the profile of the brake is such that increased Rotation A' of the parking brake about the axis of the propulsion lever, applies increasing Compression B' to the brake lever. This profile in the parking brake accounts for the brake lever's inherent range of Compression C' which is caused by variations in the point at which the brake is fully applied due to brake pad wear, wet weather, actuation variations in the hydraulic fluid or cable and lever set up and results in the final position of the lever varying when the brake is fully applied.

Claims

SCLAiMS 1. A vehicle brake locking mechanism comprising a locking member able to rotate about an axis perpendicular to that of the pivot axis of the brake actuation means such that permanent locking of the brakes is achieved until the User releases the locking member, where increased rotation of the locking member about its axis effects increased compression of the brake actuation means.
2. A vehicle brake locking mechanism according to claim I where a brake actuation means is provided by a hand operated brake lever and disc brake system where by movement of the brake lever actuates a brake calliper via hydraulics in order to apply braking force to a disc rotor and effect braking force to the ground contacting wheel. (SIo
3. A vehicle brake locking mechanism according to claim 2 whereby actuation of the brake calliper is provided by cable.
4. A vehicle brake locking mechanism according to claim 2 whereby brake actuation means is provided by a hand operated brake lever and rim brake mechanism where by movement of the brake lever actuates a brake calliper via hydraulics in order to apply braking force to the rim of the main ground contacting wheel.
5. A vehicle brake locking mechanism according to claim 4 whereby actuation of the brake calliper is provided by cable.
6. A vehicle brake locking mechanism according to claim I where the brake locking member and brake actuation means are mounted to a propulsion lever whereby reciprocating motion effects forwards movement of the device.
7. A vehicle brake locking mechanism according to daim 1 where the brake locking member and brake actuation means are mounted to the main chassis of the device.
8. A vehicle brake locking mechanism according to claim 1 wherein the angle of the profile which compresses the brake lever relative to the rotation axis results in increased rotation of the locking member about its axis effecting increased compression of the brake actuation means.
9. A vehicle brake locking mechanism according to claim I where a pivoting locking member is adjustable such that variations in the brake actuation means' brake engagement point do not affect brake locking capability. (4 (4 C1)