Supports – Stand – Tilting support surface
Reexamination Certificate
1999-04-15
2001-08-14
Braun, Leslie A. (Department: 3632)
Supports
Stand
Tilting support surface
C248S272000, C248S396000, C297S329000, C180S041000
Reexamination Certificate
active
06273389
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a motor driven self-levelling apparatus for a seat, in particular a seat of a motor vehicle.
BACKGROUND OF THE INVENTION
In off-highway motor vehicles, such as agricultural tractors, vehicles for timber cutting, disbranching and transport in the terrain, etc., it is desirable to provide an operator seat which automatically adjusts horizontally on lateral tilting of the vehicle. Such a seat improves the comfort of the operator and protects from fatigue and back pain. Forward/backward tilting is a minor problem compared with lateral tilting. It is understood that the afore-mentioned vehicles are designed for slow movement, and that, consequently, seat adjustment need only to be relatively slow.
Self-levelling apparatus of the aforementioned kind are intended for mounting under the operator seat. In most vehicles the operator seat is in a cabin the dimensions of which are determined by the manufacturer of the vehicle independently of its provision with a self-levelling apparatus. For this and other reasons there are important restrictions in the space, in particular in respect of mounting height, available for mounting the self-levelling apparatus. This restriction also affects the choice and arrangement of the heavy duty drive mechanism for compensation of inclination.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a motor driven self-levelling apparatus for a seat, which apparatus has low overall height and is suited for mounting in a spatially restricted environment.
It is another object of the invention to protect the rotating parts of the motor of a self levelling apparatus of the aforementioned kind from dirt and mechanical interference.
It is a further object of the invention to provide for simple manual levelling of the seat in case of motor or power failure.
SUMMARY OF THE INVENTION
The self-levelling apparatus according to the invention comprises a base, a seat levelling assembly displaceably connected with the base, a drive means disposed between the seat and the base for rotation of the seat levelling assembly around an axis about parallel with the base, the seat levelling assembly being disposed between the base and said axis, the drive means comprising a reversible electrical motor fixed to the seat levelling assembly in a way as to have its shaft extending parallel with said axis, said shaft being in direct or indirect engagement with a flexible actuation means fixed at its one end at the base, and further comprising a detection means for detection of the position of the seat levelling assembly in respect to the horizontal plane, the detection means being coupled to control means for control of the motor. The provision of a flexible actuation means which may comprise one or several flexible actuation elements is advantageous by, inter alia, restricting loads to tensile loads. The axis extends above the seat levelling assembly in, depending on the mounting of the apparatus in a motorised vehicle, a longitudinal or transverse direction of the vehicle and substantially in parallel with the ground on which the vehicle stands or runs.
Most commonly the apparatus according to the invention will be disposed under the seat for compensation of lateral tilting. Compensation of forward/backward tilting is of course also possible. The apparatus can be integrated with the seat and/or the vehicle body.
It is preferred for the displaceable connection of the seat levelling assembly with the base to comprise co-operating arcuate seat and base bearing elements pertaining to the seat levelling assembly and the base, respectively, of which at least one comprises a surface defined by rotation of a straight or curved or irregular line, around said first axis, in particular a cylinder segment or cone segment shaped surface. This preferably convex cylinder or cone segment shaped surface or other rotationally defined surface of an arcuate seat levelling element can co-operate with a base bearing element comprising glide, rolling or ball means arranged across a correspondingly, shaped surface, preferably a concave cylinder segment or cone segment shaped surface, and vice versa. Particularly preferred is the arcuate base bearing element to be interrupted at the level of the base plate thus forming two arcuate base bearing element portions defined by the same cylinder or cone axis and radius.
According to another aspect of the invention, it is preferred for the flexible actuation means be segmented and to preferably include a flexible segmented actuation element. Such segmented actuation elements include synchronous (toothed) belts and roller chains. They may co-operate with the motor shaft via a tooth gear or pulley fixed to the shaft. It is furthermore preferred for the segmented actuation means to comprise several segmented actuation elements. It is also preferred for the flexible actuation means to have an unloaded end fixed at the arcuate seat bearing element or an element in rigid geometric relationship with the latter, preferably by interposition of tensioning means, such as a chain adjuster.
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patent: 5857535 (1999-01-01), Brooks
patent: 6026920 (2000-02-01), Obeda et al.
patent: 6116560 (2000-09-01), Kim
patent: 8806984 (1988-09-01), None
patent: 94/07707 (1994-04-01), None
Braun Leslie A.
Carlgrens Ergonomi AB
Landry Walter
Ostrolenk Faber Gerb & Soffen, LLP
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