US 6,256,812 B1Granted

Wheeled carriage having auxiliary wheel spaced from center of gravity of wheeled base and cam apparatus controlling deployment of auxiliary wheel and deployable side rails for the wheeled carriage

AssigneeStryker Corporation

InventorsRichard J. Bartow, James R. Hanson, Richard L. McDaniel

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Abstract

A wheeled carriage for supporting a patient in a substantially horizontal position, the wheeled carriage has thereon a patient support having head and foot ends and a wheeled base supported by castered wheels. An auxiliary wheel and a wheel support structure therefor suspendedly mount the auxiliary wheel at its axis to the wheeled base at a distance L in a horizontal direction from the center of gravity of the wheeled carriage along the length of the wheeled base when the auxiliary wheel is engaged with the floor surface. A moment Mmass is defined by the distance L multiplied by a force Fmass, the force Fmass being defined by the mass of the carriage or carriage and patient at the center of gravity. The moment Mmass is greater at all times than a moment Mforce to prevent teetering of the wheeled carriage, where moment Mforce is defined by multiplying the height H by a force Fmax. The force Fmax is the force required to move the wheeled carriage. The height H is defined by the vertical distance between the axis of the auxiliary wheel and the relative height of the gripping location where the force Fmax is applied.

Claims21

Dependent claims

A wheeled carriage for supporting a patient in a substantially horizontal position, said wheeled carriage having a center of gravity and a force Fmass at the center of gravity due to the mass of said carriage or the mass of a combination of said carriage and a patient thereon, said wheeled carriage comprising:

a patient support having a length, opposing ends of the length comprising a head end and a foot end of said patient support, said patient support having a pair of lateral sides intermediate the head and foot ends;
a wheeled base having a length and supporting said patient support and enabling movement of said patient support, said wheeled base including at least four floor surface engaging and castered wheels spaced from one another, said wheeled base of said wheeled carriage having a first edge at a first end corresponding to the head end of said patient support and a second edge at a second end corresponding to the foot end of said patient support;
a gripping location at the head end of said patient support, said gripping location being utilized to apply a force Fmax to said carriage sufficient to overcome friction and move said wheeled carriage;
an auxiliary wheel mechanism including an auxiliary wheel support structure for rotatably supporting at least one auxiliary wheel at an axis thereof to said wheeled base, said at least one auxiliary wheel being uncastered, the axis of said at least one auxiliary wheel being secured to said wheeled base at a distance L in a horizontal direction from the center of gravity along the length of said wheeled base when said auxiliary wheel is engaged with the floor surface, a moment Mmass being defined by the distance L multiplied by the force Fmass;
and
control apparatus for effecting a movement of said support structure and said at least one auxiliary wheel between a first position whereat said auxiliary wheel is engaged with the floor surface and a second position whereat said auxiliary wheel is out of engagement with the floor surface,
wherein, when said auxiliary wheel is in engagement with the floor surface, the height H defined by the axis of said auxiliary wheel and the relative height of said gripping location creates a moment Mforce defined by multiplying the height H by the force Fmax,
the distance L being great enough such that the moment Mmass is greater than the moment Mforce when any size and weight of patient is placed on the patient support having their head toward the head end thereof, such that said wheeled carriage does not teeter between said castered wheels on respective ends of said carriage during movement thereof.

5 more elements

A wheeled carriage for supporting a patient in a substantially horizontal position, comprising:

a patient support having a length, opposing ends of the length comprising a head end and a foot end of said patient support, said patient support having a pair of lateral sides intermediate the head and foot ends;
a wheeled base having a length and supporting said patient support and enabling movement of said patient support, said wheeled base including at least four floor surface engaging and castered wheels spaced from one another, said wheeled carriage having a first edge corresponding to the head end of said patient support and a second edge corresponding to the foot end of said patient support, said wheeled base having an imaginary transverse centerline located at a midpoint of the length of said wheeled base and dividing said wheeled base;
an auxiliary wheel mechanism including an auxiliary wheel support structure for suspendedly supporting at least one auxiliary wheel at an axis thereof to said wheeled base, said at least one auxiliary wheel being uncastered;
and
control apparatus for effecting a movement of said auxiliary wheel support structure and said at least one auxiliary wheel between a first position whereat said auxiliary wheel is engaged with the floor surface, the axis of said auxiliary wheel being spaced from the centerline at the midpoint of said wheeled base toward the second edge of said wheeled base, and a second position whereat said auxiliary wheel is out of engagement with the floor surface.

2 more elements

A wheeled carriage for supporting a patient in a substantially horizontal position, comprising:

a patient support having head and foot ends and a pair of lateral sides intermediate said head and foot ends and a wheeled base supported on at least four floor surface engaging and castered wheels spaced from one another at locations defining corners of a theoretical polygon;
an auxiliary wheel mechanism including an auxiliary wheel support structure for suspendedly mounting at least one auxiliary wheel to said wheeled base, said at least one auxiliary wheel being oriented inside a boundary of the theoretical polygon and including an axle about which said wheel rotates, said axle being mounted to said auxiliary wheel support structure and being uncastered;
control apparatus for effecting a movement of said wheel support structure and said at least one auxiliary wheel between a first position whereat said auxiliary wheel is engaged with said floor surface and a second position whereat said at least one auxiliary wheel is out of engagement with the floor surface, said control apparatus including a rotatable shaft oriented on an axis parallel to a longitudinal axis of said rectangular patient support and having a first manually manipulatable member connected to said rotatable shaft, said first manually manipulatable member being oriented adjacent at least one of said head and foot ends;
and
cam apparatus including a first cam linkage having a first end secured to said rotary shaft of said control apparatus, a second cam linkage secured to a second end of said first cam linkage, an end of said second cam linkage being secured to a cam, and a cam follower being manipulated by said cam, said cam follower including an axle fixedly secured to said auxiliary wheel support structure, said first cam linkage having a position control member, said position control member preventing said cam linkage from contacting a floor surface during movement thereof.

2 more elements

Dependencies are inferred from the claim text.