Motor operated bed having low leakage current

Claim 2

In a motor operated, adjustable hospital bed having a lower supporting frame, a mattress supporting frame pivotally mounted on said supporting frame, actuating means for pivoting said mattress supporting frame, an electric motor mounted on said lower supportinG frame for driving said actuating means when electric power is supplied to said motor, and an on/off electrical control mounted on said lower supporting frame for receiving electrical power and controlling the supply of that electrical power to said motor, the improvement which comprises a power supply means including a transformer having isolated primary and secondary insulated windings, the electrostatic coupling between said primary and secondary windings being less than about 241 picofarads, supplementary electrical insulation encompassing said transformer, means for mounting said electrically insulated transformer on said lower supporting frame, first means for electrically connecting said primary winding to a source of alternating current power and second means for electrically connecting said secondary winding to said electrical control and for supplying the electrical power to said electrical control.

Claim 3

An apparatus according to claim 1 wherein a metal case is disposed about the supplementary electrical insulation, and insulators are disposed between the case and the lower supporting frame.

Claim 4

An apparatus according to claim 1 wherein the first electrical connecting means is a two conductor power cord.

Claim 5

An apparatus according to claim 1 wherein the transformer is designed for intermittent duty with a rating of about 50 percent of the current draw of the motor.

Claim 6

An apparatus according to claim 2 wherein the transformer is designed for intermittent duty with a rating of about 50 percent of the current draw of the motor.

Claim 7

A power supply for a motor operated, adjustable hospital bed which bed includes a lower supporting frame, a mattress supporting frame pivotally mounted on said supporting frame, actuating means for moving said mattress supporting frame with respect to said lower supporting frame, an electric motor for driving said actuating means when electric power is supplied to said motor, and an on/off electrical control mounted on said supporting frame for receiving electrical power and controlling the supply of that electrical power to said motor, said power supply comprising a transformer having a primary insulated winding and a secondary insulated winding isolated from said primary winding, the primary and secondary windings being magnetically coupled without introducing either significant conductive or significant electrostatic coupling therebetween, the electrostatic coupling between said primary and secondary windings being less than about 241 picofarads, supplementary electrical insulation about said transformer, means for mounting said electrically insulated transformer on said lower supporting frame, first means for electrically connecting said primary winding to a source of a.c. power and second means for electrically connecting said secondary winding to said electrical control and for supplying the electrical power to said electrical control.

Claim 8

A power supply for a motor operated, adjustable hospital bed which bed includes a lower supporting frame, a mattress supporting frame pivotally mounted on said supporting frame, actuating means for moving said mattress supporting frame with respect to said lower supporting frame, an electric motor for driving said actuating means when electric power is supplied to said motor, and an on/off electrical control mounted on said supporting frame for receiving electrical power and controlling the supply of that electrical power to said motor, said power supply comprising a transformer having a primary insulated winding and a secondary insulated winding isolated from said primary winding, the primary and secondary windings being magnetically coupled without introducing either significant conductive or significant electrostatic coupling therebetween, the electrostatic coupling between said primary and secondary windings being less than about 241 picofarads, supplementary electrical insulation about said transformer, means for mounting said electrically insulated transformer on said lower supporting frame, first means for electrically connecting said primary winding to a source of a.c. power and second means for electrically connecting said secondary winding to said electrical control and for supplying the electrical power to said electrical control.

Claim 9

A power supply in accordance with claim 6 wherein a metal case is disposed about the supplementary insulation, and insulators are disposed between the case and the lower supporting frame.

Claim 10

An apparatus according to claim 6 wherein the first electrical connecting means is a two conductor power cord.

Claim 11

An apparatus according to claim 6 wherein the transformer is designed for intermittent duty with a rating of about 50 percent of the current draw of the motor.

Claim 12

An apparatus according to claim 7 wherein the transformer is designed for intermittent duty with a rating of about 50 percent of the current draw of the motor.