Stair chair

Details Stair chair Stair chair

2002-07-24

2003-11-11

Lerner, Avraham (Department: 3611)

Land vehicles

Wheeled

Occupant propelled type

C280S642000, C280S047315, C280S047250, C280SDIG001, C280S005260

Reexamination Certificate

active

06644675

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to chairs and to a method of moving chairs. The invention is particularly, although not exclusively, applicable to chairs that are for use in an emergency such as chairs for evacuating buildings and chairs for maneuvering patients.
SUMMARY OF THE INVENTION
According to one aspect of the present invention a stair chair is provided and includes at least one wheel assembly constrained to rotate about an assembly axis, the at least one wheel assembly comprising a plurality of wheels with each wheel being rotatable about its own wheel axis.
The chair may include means for selectively engaging and disengaging the wheel assembly arranged to resist rotation of the wheel assembly about the assembly axis. The means to resist rotation about the assembly axis may comprise means to prevent rotation about the assembly axis. Those means to prevent rotation about the assembly axis may comprise locking means.
The locking means may comprise a retractable plunger movable from a first position in which the plunger engages the wheel assembly and another part of the chair and a second position in which the plunger is disengaged from the wheel assembly. The plunger may be movable by a pivotal cam. The plunger may be biased towards the first position.
The locking means may be arranged to cooperate with an axle portion defining the assembly axis. The locking means may be arranged to cooperate with the axle portion in a central region of the axle. The locking means may be arranged to cooperate with the axle such that the axle can be locked in one or more positions, for example three positions. These positions may be equally angularly spaced from each other.
The means to resist rotation about the assembly axis may comprise a brake. The brake may be arranged to induce friction to resist rotation. The brake may be arranged to vary the friction force. The brake may comprise an arcuate member.
The arcuate member may be pivotally connected to the chair and movable about that pivot to apply or increase friction or to remove or decrease friction or any combination thereof. The pivot of the arcuate member may be arranged to be caused by an operating means. The operating means may comprise a threaded portion that is arranged to engage with a threaded member whereby relative rotation of the threaded portion and the threaded member is arranged to cause axial movement of the threaded portion to cause pivotal movement of the arcuate member.
Relative rotation of the threaded portion to the threaded member may be arranged to occur in opposed directions to cause axial movement of the threaded portion in one of two opposed directions.
The operating means may include moveable means for engaging and disengaging the threaded portion whereby reciprocal movement of the movable means is arranged to cause rotational movement of the threaded portion in one rotational direction only by engaging the threaded portion when moving the operating member in one direction of the reciprocal movement and disengaging this threaded portion in the opposite direction of reciprocal movement.
The assembly axis may be defined by an axle. The brake may be arranged to act on a downwardly facing portion of the axle. The brake may be arranged to engage with an enlarged portion of the axle.
The brake may comprise a pivotal operating member movable between a first position in which a brake portion does not have any significant braking effect and a second position in which the brake member is urged to resist rotation of the axle. Movement of the operating member may be arranged to move the brake between both positions.
The operating member may be arranged to be in an over center position when in at least one of the positions. For instance, when the brake is applied, the operating member may have to go through a pivotal position in which more force would be applied to the brake prior to returning to the first position. Alternatively, or additionally, resilient means may be arranged to bias the brake into an operative or inoperative position or both.
The operating member may be connected to a rotatable shaft at a location radially offset from the longitudinal axis of the shaft.
The brake may be adjustable whereby the length of the brake portion from the operating member to the axle is adjustable, for example by rotating a threaded portion of the brake portion.
The brake may be operable by the foot of an operator, for example both to apply the brake and to remove the brake. The chair may include an axle defining the wheel assembly axis. The brake and the locking means may be arranged to cooperate with the same axial extent of the axle. The brake and locking means may be arranged to act on opposite sides of the axle. The brake and the locking means may be arranged to cooperate with an enlarged portion of the axle.
The brake or alternatively or additionally the locking means may have the parts that cooperate with the axle concealed. The at least one wheel assembly may comprise three wheels.
The chair may include two wheel assemblies at opposed side regions of the chair. The two wheel assemblies may be constrained to rotate together about a common axis.
According to a further aspect of the present invention, a method of moving a stair chair which includes at least one wheel assembly that is constrained to rotate about an assembly axis in which the at least one wheel assembly comprises a plurality of wheels with each wheel being rotatable about its own wheel axis, the method comprising providing a support for the stair chair by at least one wheel from the wheel assembly and rolling the stair chair on at least one wheel.
The method may comprise providing support for the chair by at least two wheels of the wheel assembly.
The method may comprise preventing rotation of the assembly axis relative to the remainder of the chair whereby a single wheel of the wheel assembly is able to provide the support for the chair.
The method may comprise imposing a braking force on the assembly axis whereby resistance to rotation about the assembly axis is imposed. The method may comprise varying that resistance. The method may comprise imposing the resistance to rotation about the assembly axis when the chair is being moved down steps or down stairs.
The method may comprise the wheel assembly rotating about the assembly axis when the chair is being moved up or down steps or stairs such that successive wheels of the wheel assembly are caused to engage with the step or stairs. The method may comprise the chair pivoting about both a wheel axis and the assembly axis as the chair undergoes at least a part of its movement relative to steps or stairs. The method may comprise at least two wheels engaging the step or stairs as the chair undergoes movement relative to the step or stairs. The method may comprise at least two wheels of the or each wheel assembly rotating about their wheel axis as the chair undergoes movement along the step or stairs. The method may comprise one wheel rotating about its wheel axis and engaging an upwardly facing portion of a stair and another wheel engaging a generally horizontal portion of a step and rotating about its wheel axis or stair simultaneously as the chair is moved relative to the step or stairs.
According to another aspect of the present invention a foldable stair chair includes a backrest, a seat and a foot rest, the seat and foot rest being movable relative to the backrest from an operative position in which the backrest projects upwardly, the seat projects forwardly and the foot rest is located at a lower elevation than the seat, to a storage position in which the seat is located adjacent to the backrest and the foot rest is located adjacent to the seat.
In the storage position, the backrest, seat and foot rest may be generally parallel to each other. In the storage position at least two of the backrest, the seat and the foot rest may be in contact with each other and preferably all three of the backrest, seat and foot rest are in contact with each other.
In the operative position the

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