Wheeled carriage having a powered auxiliary wheel, auxiliary wheel overtravel, and an auxiliary wheel drive and control system

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 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 support structure secured to said wheeled base and suspendedly supporting at least one auxiliary wheel at an axis thereof to said wheeled base, wherein the axis of said at least one auxiliary wheel is spaced from the centerline at the midpoint of said wheeled base toward the second edge of said wheeled base, said auxiliary wheel support structure including a floating frame;
• and
• a control apparatus for controlling said auxiliary wheel support structure to move said at least one auxiliary wheel between a first deployed position whereat said auxiliary wheel is engaged with a floor surface and a second stored position whereat said auxiliary wheel is out of engagement with the floor surface,
• wherein, when a portion of the floor surface has a lower depth directly below said at least one deployed auxiliary wheel such that the four surface engaging wheels engage the floor surface, said floating frame of said auxiliary wheel support structure moves downwardly along with said at least one auxiliary wheel mounted thereto to maintain said at least one auxiliary wheel in contact with the lowered floor surface.

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 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 support structure secured to said wheeled base and suspendedly supporting at least one auxiliary wheel at an axis thereof to said wheeled base, wherein the axis of said at least one auxiliary wheel is spaced from the centerline at the midpoint of said wheeled base toward the second edge of said wheeled base, said auxiliary wheel support structure including a loading frame pivotally mounted to said wheeled base and a floating frame mounted to said loading frame;
• and
• a control apparatus for controlling said auxiliary wheel support structure to move said at least one auxiliary wheel between a first deployed position whereat said auxiliary wheel is engaged with a floor surface and a second stored position whereat said auxiliary wheel is out of engagement with the floor surface,
• wherein, when a portion of the floor surface has a lower depth directly below said at least one deployed auxiliary wheel such that the four surface engaging wheels engage the floor surface, said floating frame of said auxiliary wheel support structure moves downwardly along with said at least one auxiliary wheel mounted thereto to maintain said at least one auxiliary wheel in contact with the lowered floor surface.

A power assisted 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 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;
• an auxiliary wheel support structure secured to said wheeled base and suspendedly supporting at least one auxiliary wheel about an axis transverse to the length of said wheeled base;
• a control apparatus for controlling said auxiliary wheel support structure to move said at least one auxiliary wheel between a first deployed position in contact with a floor surface, and a second stored position whereat said at least one auxiliary wheel is out of engagement with the floor surface;
• an auxiliary wheel drive power circuit for driving said at least one auxiliary wheel;
• a processor for controlling the auxiliary wheel drive power circuit to control acceleration, deceleration, velocity and direction of driving of said at least one auxiliary wheel;
• a drive member at an end of said wheeled carriage for receiving a force input from a user in one of first and second opposing directions;
• and
• a load cell for measuring the force input applied to said drive member, and providing an output to said processor,
• wherein said processor controls driving of said at least one auxiliary wheel in response to the force input and the direction of the force input applied to said drive member.

A power assisted wheeled carriage for supporting and transporting a person 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;
• 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 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;
• an auxiliary wheel support structure secured to said wheeled base and for supporting at least one auxiliary wheel about an axis transverse to the length of said wheeled base, and moving said at least one auxiliary wheel into a first deployed position contacting the floor and a second stored position out of engagement with the floor;
• a drive motor for driving said auxiliary wheel;
• a power drive control circuit for controlling said drive motor;
• a drive member mounted on the wheeled carriage for providing a drive signal in one of a first direction and a second opposing direction;
• a drive and control system for receiving the drive signal and for driving said at least one auxiliary wheel by providing a power signal to said power drive control circuit;
• and
• a drive motor disconnect arrangement for open circuiting said drive motor from said power drive control circuit to enable manually powered movement of said wheeled carriage, said drive motor disconnect arrangement including first and second disconnect elements for disconnecting said drive motor from said power drive control circuit and from a parallel circuit.

A power assisted wheeled carriage for supporting and transporting a person 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;
• a wheeled base having a length and supporting said patient support and enabling movement of said patient support;
• an auxiliary wheel support structure secured to said wheeled base and suspendedly supporting at least one auxiliary wheel at an axis thereof to said wheeled base;
• a control apparatus for controlling said auxiliary wheel support structure to move said at least one auxiliary wheel between a first deployed position whereat said auxiliary wheel is engaged with a floor surface and a second stored position whereat said auxiliary wheel is out of engagement with the floor surface;
• a drive motor for driving said auxiliary wheel;
• a power drive control circuit for controlling said drive motor;
• a drive member for receiving an input from a user in one of a first direction and a second opposing direction;
• an input measuring device for measuring the input from the drive member and providing a drive signal;
• a drive and control system for receiving the drive signal from said input measuring device, said drive and control system comparing the value of the drive signal with a drive signal threshold value, and providing a power signal to said power drive control circuit for driving said at least one auxiliary wheel in response to the value of the drive signal and the direction of the drive signal when the drive signal value exceeds the drive signal threshold value.

A method for driving a power assisted wheeled carriage used for supporting and transporting a person in a substantially horizontal position, the carriage including a patient support having a length, opposing ends of the length comprising a head end and a foot end of said patient support, a wheeled base having a length and supporting said patient support and enabling movement of said patient support, an auxiliary wheel support structure secured to said wheeled base and for biasing at least one auxiliary wheel into a first position contacting the floor and a second raised position out of engagement with the floor, and a drive motor for driving said at least one auxiliary wheel, the method including the steps of:

• (a) sensing the presence of a force input by an operator to a drive member for controlling driving of said at least one auxiliary wheel in a first direction, and when the force input is absent, maintaining the velocity of said at least one auxiliary wheel and returning to a main program;
• and
• (b) measuring magnitude of the force input and direction of the force input applied by the operator, and
• (i) when the direction of the force input is in the direction as previously sensed, sensing if the velocity is at a maximum velocity, and (1) maintaining the velocity of the wheeled carriage when the velocity is at a maximum value, and (2) when the velocity is not at a maximum value, using the magnitude of the force input to determine an acceleration rate;
• (ii) when the direction of the force input is not in the direction as previously sensed, sensing if the velocity is at zero velocity, and (1) when the velocity of the wheeled carriage is at zero, using the force input to determine an acceleration rate in the direction of the force applied by the operator, and (2) when the velocity is not at zero, using the force to determine a deceleration rate.

A power assisted wheeled carriage for supporting and transporting a person 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;
• 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 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;
• an auxiliary wheel support structure secured to said wheeled base and for supporting at least one auxiliary wheel about an axis transverse to the length of said wheeled base, and moving said at least one auxiliary wheel into a first deployed position contacting the floor and a second stored position out of engagement with the floor;
• a drive motor for driving said auxiliary wheel;
• a power drive control circuit for controlling said drive motor;
• a drive member mounted on the wheeled carriage for providing a drive signal in one of a first direction and a second opposing direction;
• a drive and control system for receiving the drive signal and for driving said at least one auxiliary wheel by providing a power signal to said power drive control circuit;
• and
• a drive motor disabling device for providing a parallel electrical connection across said drive motor to prevent a voltage improperly applied to said drive motor from powering said drive motor and to resist or slow uncontrolled movement of said wheeled carriage.

A power assisted wheeled carriage for supporting and transporting a person 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;
• 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 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;
• an auxiliary wheel support structure secured to said wheeled base and for supporting at least one auxiliary wheel about an axis transverse to the length of said wheeled base, and moving said at least one auxiliary wheel into a first deployed position contacting the floor and a second stored position out of engagement with the floor;
• a drive motor for driving said auxiliary wheel;
• a power drive control circuit for controlling said drive motor;
• a drive member mounted on the wheeled carriage for providing a drive signal in one of a first direction and a second opposing direction;
• a drive and control system for receiving the drive signal and for driving said at least one auxiliary wheel by providing a power signal to said power drive control circuit;
• and
• a voltage system sensor unit for sensing a change in system voltage over a predetermined time and calculating a measured voltage change value,
• wherein said drive and control system, compares said measured voltage change value with a predetermined value, and when said measured value is greater than the predetermined value, said drive and control system changes the power signal to said power drive control circuit to maintain the velocity of said wheeled carriage at a constant velocity.

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 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 support structure secured to said wheeled base and suspendedly supporting at least one auxiliary wheel at an axis thereof to said wheeled base, wherein the axis of said at least one auxiliary wheel is spaced from the centerline at the midpoint of said wheeled base toward the second edge of said wheeled base;
• and
• a control apparatus for controlling said auxiliary wheel support structure to move said at least one auxiliary wheel between a first deployed position whereat said auxiliary wheel is engaged with a floor surface and two of said floor engaging wheels adjacent said foot end of said wheeled carriage are elevated away from the floor surface when the floor surface is even, and a second stored position whereat said at least one auxiliary wheel is out of engagement with the floor surface;
• and
• a retraction damper unit for slowing movement of said at least one auxiliary wheel from the deployed position toward the stored position to decrease a force caused when the two of said floor engaging wheels adjacent said foot end of said wheeled carriage contact the floor surface during raising of said at least one auxiliary wheel.

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 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 including first and second spaced elongate frame members extending the length of said wheeled base;
• an auxiliary wheel support structure secured to said wheeled base and suspendedly supporting at least one auxiliary wheel at an axis thereof to said wheeled base, wherein the axis of said at least one auxiliary wheel is spaced from the centerline at a midpoint of said wheeled base toward the second edge of said wheeled base, said auxiliary wheel support structure comprising:
• a push rod pivotally secured at a first end to said wheeled base;
• and
• a linkage element having a first end movable when said auxiliary wheel support structure is moved between a first deployed position whereat said auxiliary wheel is engaged with a floor surface and a second stored position whereat said auxiliary wheel is out of engagement with the floor surface, a second end of said push rod being pivotally secured to a second end of said linkage element;
• and
• a control apparatus for coacting with the first end of said linkage element to move said at least one auxiliary wheel between the first deployed position and the second stored position,
• wherein, when a portion of the floor surface has a lower depth directly below said deployed auxiliary wheel such that the four surface engaging wheels engage the floor surface, said auxiliary wheel support structure enables downward movement of said at least one auxiliary wheel from said deployed position so that said auxiliary wheel maintains contact with the floor surface, and
• wherein the second ends of said linkage element and said push rod are at a raised position relative to said frame members when said auxiliary wheel is in the deployed position and the second ends of said linkage element and said push rod are at a lowered position relative to said frame members when said auxiliary wheel is in the second stored position.