Miscellaneous hardware (e.g. – bushing – carpet fastener – caster – Casters – Locked
Patent
1991-10-22
1993-11-23
Larson, Lowell A.
Miscellaneous hardware (e.g., bushing, carpet fastener, caster,
Casters
Locked
16 20, B60B 3302
Patent
active
052632261
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to the wheel assembly for a cart or other mobile mechanism, of the type which contains a wheel which swivels around a vertical axle, and may be locked or unlocked by the rotation of the latter in one direction or the other. Such wheel assemblies include a thrust bearing with at least one circular housing fixed by axle, a fork joint with at least two lateral extensions whose lower ends support the wheel's horizontal axle, and one upper circular cover connected to the upper ends of the lateral extensions. The cover cooperates with bearings placed around the lower end of the vertical axle so that the fork joint can rotate around the latter. Prior art wheel assemblies are known to contain devices for locking the fork joint in relation to the vertical swivel axle. Such devices are disclosed, for example, in British Patent GB-A-2106-378.
In the device disclosed in the '378 patent, part of the fork joint's locking device is accessible from the outside and may be damaged. Because of this, the proper operation of the device cannot be assured on an ongoing basis. Moreover, the known wheel assembly of this patent requires a major modification to the fork joint, particularly in the area of the wheel axle, which must be capable of moving in the oblong openings made in the fork joint. Another problem with this known swivelling wheel is the fact that controlling the unlocking of the fork joint entails abruptly stopping the wheel for an instant. In addition, the locking devices for the known swivelling wheel assembly have a large number of unprotected individual parts, and are therefore, subject to rapid wear and deterioration.
SUMMARY OF THE INVENTION
The purpose of the present invention is to eliminate such problems and to provide a swivelling wheel which is simple in design, protected against external damage, and has a reduced number of individual parts.
Within the framework of a swivelling wheel assembly of the type referred to above, the assembly of the present invention includes a double control lever which is pivotally mounted in the space between the external housing of the fork joint and the wheel's tread in the area of the fork joint's lateral extensions. The lever is in the form of a curved lever whose two arms encompass an angle of between 90.degree. and 160.degree.. The lower arm moves between two outermost positions located in proximity to a radial plane running through the pivot axis of the lever and the wheel's axis of rotation. The lower lever arm has at its lower end a friction device which is resiliently urged into engagement with the wheel's tread. The upper lever arm is housed in the space enclosed by the fork joint above the wheel's tread, and includes, as a locking means a tip which extends perpendicularly to the lever's pivot axle, and in the direction toward the periphery of the fork joint. A second locking means consists of a locking slot for receiving the locking tip without any significant lateral play. The slot is constructed in the lower end of the vertical swivel axle or a component which is an integral part of the latter. One of the two stops for limiting the pivoting movement of the control lever is placed in the space located about the wheel and between the lateral extensions of the fork joint. This stop works in conjunction with a first lower portion of the control lever. The second stop consists of either the bottom of the locking slot, or the lower bottom edge of the component containing the locking slot, and works in conjunction with the upper lever arm's locking tip.
A circular cover of the fork joint contains a tracking groove extending along the center plane of the fork joint and perpendicular to both the wheel axle and the control lever's pivot axle. The tracking groove operates to guide, without significant lateral play, a portion of the upper lever arm or the locking tip along its entire path between the two outermost positions of the lever.
With the construction of the present invention, the locking device is completely pro
REFERENCES:
patent: 2583858 (1949-02-01), Kostolecki
patent: 2799514 (1957-07-01), Kramczak
patent: 3751757 (1973-08-01), Stosberg et al.
patent: 4494272 (1985-01-01), Morita
patent: 5040265 (1991-08-01), France et al.
Hrabina Jean
Roy Jean-Pierre
Guitel-Etienne Mobilor
Gurley Donald M.
Larson Lowell A.
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