Hill-Rom Company, Inc.

James S Adams

William H Peck

Daniel R Tekulve

Charles W Cutler

Leslie Dale Foster

Beds, such as hospital beds, in which at least some portion of the bed is movably actuated by an electric motor (or motors) are provided with a control circuit to determine proper energization of the motor from an AC power source. Since the AC signal from the power source could be harmful to the person selecting a desired direction of travel of the movable portion of the bed, the selecting portion of the control circuit is isolated by appropriate transformers from the power portion that supplies the motor. Bidirectional switching devices, such as triacs, are utilized to convey the power to the motor. Other bidirectional switching devices, such as triacs, are used to gate the power handling triacs through appropriate gating transformers. A phase shifting arrangement is utilized in connection with the gating transformers to provide proper commutation of the power handling triacs. Supplemental features, such as additional locations of the control and limit switches to establish maximum distance of travel may be employed. When both head and knee movable portions are utilized, a contour circuit may be employed to automatically adjust the knee portion upon variation of the head portion, within certain limits of travel. A disconnect arrangement employing a self-gating triac is utilized to automatically open a hot line to the common of one of the motors unless the energizing circuit for that motor is completed.

Control circuit for hospital bed

An improved control and locking device for a hospital bed such as that disclosed in U.S. Patent Application Ser. No. 496,212, filed on Aug. 9, 1974. The locking device is utilized to provide a positive lock of the hospital bed in a Trendelenburg or reverse Trendelenburg position and eliminate the capability to manualy or inadvertently remove the bed from such position. As depicted herein, the locking device is a pivotal abutment which normally precludes release of a hook holding the bed in a Trendelenburg position. Yet, when the entire bed is raised by its electric motor, the abutment is automatically withdrawn from its abutting, locking position to permit the bed to lower under electric power.

Elevating and Trendelenburg mechanism for an adjustable bed

Ground-test device indicating when the connection to ground has become lost and passing no more than about 12 microamperes of current into the ground system. The device also develops an indication when the wiring from the source of a.c. power suffers from reversed polarity or when the common, or neutral, connection floats appreciably above ground. When no abnormality exists, the circuit introduces less than about 0.6 microamperes to ground.

Ground-test circuit with minimal ground current

An elevating and Trendelenburg mechanism for a hospital bed providing elevated Trendelenburg positions and positive latching of cooperating members. Two torque tubes pivotally attach to an elevating frame. Lift arms welded to the torque tubes support the frame at various elevations. A motor on the frame produces rotation of a yoke pivotally attached to one of the torque tubes. The yoke abuts a first drive arm rigidly attached to the tube to lift one end of the frame, and a second drive arm pivotally attached to the tube. A rod connects the second drive arm to a pivot plate as a second rod connects the pivot plate to a third drive arm welded to the other torque tube to lift the other end of the bed. When the frame raises to about its maximum height, one of two hooks on the frame may prevent the first or second drive arm from following a receding yoke, with the result that one end of the bed remains elevated while the other lowers. When not so engaged with the hooks, the second and third drive arms latch onto the yoke to prevent externally produced relative motion of the components.

Bed guard rotatable between elevated and lowered positions and slidable from the latter to a position underneath the bed. While elevated, it prevents accidental falling off, and when underneath, it allows facile patient management and movement of the bed through narrow passageways. Where the bed incorporates one or more electric motors to alter its configuration, the guard may additionally or alternatively include the patient controls for the motors.

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Batesville, IN, United States of America

James S Adams