Braking and steering system for a mobile support
A mobile support such as a stretcher includes a left rear rolling element and a right rear rolling element. The support also includes a sensor system adapted to sense displacement force applied to the support, and a deceleration system. Provided the bed is moving in a forward direction, machine readable instructions executed by a processor cause the deceleration system to apply a decelerating influence to selected members of the set of rolling elements in response to the sensed displacement force in order to assist braking and steering maneuvers.
1. A mobile support comprising:
a set of unpowered rolling elements supporting a stretcher including adjustable side rails and a mattress, the set of rolling elements comprising a left rear rolling element and a right rear rolling element;
a sensor system adapted to sense displacement force applied to the support;
a deceleration system arranged to apply a decelerating influence to a subset of the rolling elements;
a processor;
an energy conversion device disposed between at least one rolling element and a frame of the support, the energy conversion device including an extended axle coupled with the at least one rolling element;
machine readable instructions which, when executed by the processor, and provided the mobile support is moving in a forward direction, cause the deceleration system to apply the decelerating influence to selected members of the set of rolling elements in response to the sensed displacement force as set forth below:
Displacement
Force
Combination
Application of
Left
Right
Force Relationship
Decelerating Influence
Push
Push
Right push > Left Push
Dominant on Left Side
Push
Push
Left push > Right Push
Dominant on Right Side
Push
Pull
Dominant on Right Side
Pull
Pull
Substantially Equal on Left
and Right
Pull
Push
Dominant on Left Side,
wherein a determination of displacement force inequality is subject to an inequality tolerance, and wherein the inequality tolerance increases with increasing displacement force.
2. The mobile support of claim 1 wherein the set of rolling elements includes a left front rolling element and a right front rolling element and the specified decelerating influence is applied predominantly to the rear rolling element or elements.
3. The mobile support of claim 2 wherein the specified decelerating influence specified is applied exclusively to the rear rolling element or elements.
4. The mobile support of claim 1 wherein a determination of whether a displacement force should result in the application of the decelerating influence is subject to a force tolerance.
5. The mobile support of claim 1 including a left handle and a right handle and wherein the sensed displacement force depends on user force exerted on one or both handles.
6. The mobile support of claim 1 wherein the decelerating influence is provided by a mechanical brake.
7. The mobile support of claim 1 , wherein energy required to apply the decelerating influence is provided by the energy conversion device.
8. The mobile support of claim 1 , wherein application of the decelerating influence is effected by applying a load to the energy conversion device.
9. The mobile support of claim 1 including a propulsion unit.
10. The mobile support of claim 1 in which the machine readable instructions, when executed by the processor, and provided the mobile support is moving in a rearward direction, causes the deceleration system to apply the decelerating influence to selected members of the set of rolling elements in response to the sensed displacement force as set forth below:
Displacement
Force
Combination
Application of
Left
Right
Force Relationship
Decelerating Influence
Push
Push
Substantially Equal on Left
and Right
Push
Pull
Dominant on Left Side
Pull
Pull
Right Pull > Left Pull
Dominant on Left Side
Pull
Pull
Left Pull > Right Pull
Dominant on Right Side
Pull
Push
Dominant on Right Side.
11. The mobile support of claim 10 wherein the set of rolling elements includes a left front rolling element and a right front rolling element and the specified decelerating influence is applied predominantly to the rear rolling element or elements.
12. The mobile support of claim 11 wherein the specified decelerating influence is applied exclusively to the rear rolling element or elements.
13. The mobile support of claim 1 in which the machine readable instructions, when executed by the processor, and provided the mobile support is in an initial condition of being substantially translationally immobile, cause the deceleration system to apply the decelerating influence to selected members of the set of rolling elements in response to the sensed displacement force as set forth below:
Displacement
Force
Combination
Application of
Left
Right
Force Relationship
Decelerating Influence
Push
Push
None
Push
Pull
Left Push > Right Pull
Dominant on Right Side
Push
Pull
Right Pull > Left Push
Dominant on Left Side
Pull
Pull
None
Pull
Push
Left Pull > Right Push
Dominant on Right Side
Pull
Push
Right Push > Left Pull
Dominant on Left Side.
14. The mobile support of claim 13 wherein the set of rolling elements includes a left front rolling element and a right front rolling element and the specified decelerating influence is applied predominantly to the rear rolling element.
15. The mobile support of claim 14 wherein the specified decelerating influence is applied exclusively to the rear rolling element or elements.
16. A mobile support comprising:
a framework including a base and a mattress elevatable relative to the base;
a set of unpowered rolling elements coupled to the framework and comprising a left front rolling element, a right front rolling element, a left rear rolling element and a right rear rolling element;
a support frame;
a set of energy conversion devices, each individual energy conversion device having a drive shaft, wherein one energy conversion device is disposed between each rolling element and the support frame;
a sensor system adapted to sense displacement forces applied to the support;
a deceleration system arranged to apply a decelerating influence to a subset of the rolling elements, wherein the subset of the rolling elements includes at least one of the left front rolling element, the right front rolling element, the left rear rolling element, and the right rear element;
a control system which commands application of a decelerating influence to selected members of the set of rolling elements, the selected members being chosen as a function of a lateral imbalance between two displacement forces so that the mobile support follows a desired trajectory, wherein a determination of displacement force inequality is subject to an inequality tolerance.