Blocking device

Details Blocking device Blocking device

1999-06-15

2001-05-29

Schwartz, Christopher P. (Department: 3613)

Brakes

Vehicle

C188S017000, C188S031000

Reexamination Certificate

active

06237724

ABSTRACT:

This invention concerns a blocking device for a vehicle wheel, in particular that on a wheelchair.
It is known that wheelchair type vehicles often comprise two main wheels arranged on the outside of the frame, with the hub easily accessible to the hand of the wheelchair user. In certain cases, a ring fixed to the wheel around the hub, on the outer side, enables the chair to be moved without using a drive mechanism or motor. However, it is also desirable to be able to stop the vehicle safely and, to this effect, a blocking device has already been proposed (U.S. Pat. No. 5,379,866) which is controlled by a lever fitted to the outside end of the hub. This known device comprises a mechanism with a moving part and a fixed part which engage in each other in the blocked position, controlled by the lever. However, with this known device, the two parts of the mechanism are housed in the hub. This arrangement may seem relatively compact, but the result is that it is not possible to equip the wheelchair with the hub journal easily demountable for removal of the wheel. This blocking device has not been used as it is not very practical. To date, the preference has been for a lever device which acts on the tire. However, this device does not ensure safe blocking as firstly it depends on the tire pressure and secondly it may slip on the tire.
The purpose of this invention is thus to propose a blocking device that can be fitted to a vehicle with wheels fitted to demountable journals, without obstructing dismantling, the device being of compact size and ensuring secure operation.
To this effect, this invention concerns a wheel blocking device in relation to a vehicle frame element, in particular of a wheelchair, comprising a journal linked to the frame, a wheel hub pivoting on the journal by means of bearings, a pivoting lever, mounted at the end of the hub opposite the frame, and a blocking mechanism which comprises a fixed part that is integral with the frame element and a moving part which engages in the fixed part in the blocking position, controlled by the lever, this device being characterised in that the fixed part has blocking components directly integral with the frame element, arranged around the shaft of the journal, and in that this moving part comprises blocking elements corresponding with the fixed components and joined to the lever by means of links that extend along the shaft outside the bearings.
The blocking elements of the moving part can be situated in a recess in the hub on the frame side, said moving part, on which one or more springs may act, holding it in a stable position at least in the blocking position, also possibly comprising two link rods that cross the hub axially at a distance from the shaft greater than the external diameter of the bearings and a means of supporting and pivoting the lever, at the outer ends of the rods; these springs may act permanently in the direction of the fixed blocking components and the means of supporting and pivoting the lever may comprise two diametrically opposite pivoting spindles, for two arms of the lever, these arms having cams which bear on the circumference of the hub in such a way as to control the axial displacement of the moving part in response to the pivoting of the lever.
Springs may also be combined with the lever, the geometry of the link between the cams and the moving part of the mechanism being designed such that the lever pivots 180 degrees between the blocked position and the released position, these two positions being stabilised by the force of the springs or the elasticity due to the shape of the lever.
According to one embodiment, the fixed blocking components are formed by one or more pins, this pin or these pins working with holes or notches in the moving part.
According to another embodiment, the fixed blocking components are formed by one or more holes or notches made in a ring fixed to an upright of the frame coaxially to the journal, this (or these) hole(s) or notches(s) working with one end of one or more link rods forming part of the moving part of the mechanism.
The link between the lever and the moving part of the mechanism may be arranged such that the lever has two static positions orientated 90 degrees or 180 degrees in relation to each other, one being the blocking position and the other the release position.


REFERENCES:
patent: 1863349 (1932-06-01), Noelting et al.
patent: 4280595 (1981-07-01), Timms et al.
patent: 4679862 (1987-07-01), Luo
patent: 5379866 (1995-01-01), Pearce et al.
patent: 47650/85 (1984-09-01), None
patent: 42 01 745 (1993-01-01), None
patent: 2 588 513 (1985-10-01), None
patent: 2 725 128 (1994-09-01), None

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