High/low bed and rotational linkage for driving the high/low bed
A high/low bed comprising a main frame and a pivot plate for supporting for pivotal movement an actuator rod for raising and lowering the main frame relative to a supporting surface. The pivot plate is supported for rotation relative to the main frame via a first pivot point. The pivot plate is further supported for rotation in a plane substantially parallel to the main frame.
1 . A high/low bed comprising:
a main frame; and
a pivot plate supporting for pivotal movement at least one actuator rod for raising and lowering the main frame relative to a supporting surface, the pivot plate being supported for rotation relative to the main frame via a first pivot point, the pivot plate further being supported for rotation in a plane substantially parallel to the main frame.
2 . The bed of claim 1 , further comprising a pair of actuator rods, including the at least one actuating rod, supported for pivotal movement relative to the pivot plate.
3 . The bed of claim 2 wherein each of the actuator rods is supported for pivotal movement relative to the pivot plate via a second pivot point, the second pivot point of each of the actuator rods being oppositely disposed relative to the first pivot point and spaced equidistantly apart from the first pivot point.
4 . The bed of claim 3 wherein each of the actuator rods extends from the pivot plate to a corresponding link assembly for driving legs at head and foot ends of the main frame.
5 . The bed of claim 4 wherein the pivot plate is driven for rotation by an actuator.
6 . The bed of claim 5 wherein the actuator is supported for pivotal movement at a first end relative to the pivot plate at a third pivot point, and wherein a second end of the actuator is pivotally displaceable relative to the main frame at a fourth pivot point.
7 . The bed of claim 6 wherein mechanical advantage of the pivot plate increases and speed of rotation of the pivot plate decreases with an increase in distance between the first and third pivot points.
8 . The bed of claim 5 wherein movement of the actuator rotates the pivot plate about the first pivot point to simultaneously drive each of the actuator rods, which in turn simultaneously drive the link assemblies, which in turn drive the legs.
9 . The bed of claim 5 wherein the pivot plate functions as a lever arm so that the actuator may provide a greater mechanical advantage.
10 . The bed of claim 1 wherein one or more other actuators are connected to the pivot plate for rotating the pivot plate.
11 . The bed of claim 10 wherein one of the actuators is connected to the pivot plate so as to move in a first direction while another one of the actuators is connected to the pivot plate so as to move in a second direction opposite the first direction.
12 . The bed of claim 10 wherein two of the actuators are connected to the pivot plate so as to move in the same direction.
13 . The bed of claim 10 wherein four of the actuators are connected to the pivot plate so as to simultaneously move the pivot plate to raise and lower the main frame relative to the supporting surface.
14 . The bed of claim 2 wherein the actuator rods are pivotally connected to the pivot plate via tie rod ends so as to allow at least two degrees of freedom between the actuator rods and the pivot plate.
15 . A high/low bed comprising:
a main frame;
a pivot plate supported for rotation relative to the main frame via a first pivot point;
an actuator connected to the pivot plate and providing actuator force that rotationally drives the pivot plate; and
a pair of actuator rods supported for pivotal movement by the pivot plate so that the actuator force drives the actuator rods in opposite directions to raise and lower the main frame relative to a supporting surface.