Support appliances having articulated sections

Claim 2

Apparatus for maintaining a raisable member in a predetermined raised position with an inflatable bellows, comprising: a bellows adapted to support said member, a pressure source, a first conduit having a first valve therein and connected between said bellows and said pressure source, a second conduit having a second valve therein and connected between said bellows and said pressure source, said first valve including a rotatable conduit rotatable between a valve-open and a valve-closed position, a pulley frictionally engaging said rotatable conduit whereby rotation of said pulley in one sense rotates said rotatable conduit from said valve-open position to said valve-closed position but no further and rotation of said pulley in the opposite sense rotates said rotatable conduit from said valve-closed position to said valve-open position but no further, and a line connected to said raisable member and passed around said pulley in such a manner that if said member falls from said predetermined position, said line rotates said first valve from a valve-closed to a valve-open position, thereby admitting pressurized air to said bellows and restoring the raisable member to its predetermined position.

Claim 3

Apparatus according to claim 1 in which the rotatable conduit of said first valve is formed in a body member which is rotatable between abutments, said abutments being adjustable to allow the raisable member to fall by a finite distance before said first valve rotates from said valve-closed position to said valve-open position.

Claim 4

Apparatus according to claim 1 in which the frictionally engaging pulley and first valve constitutes a friction clutch enabling the pulley to slip with respect to the first valve whenever there is a tendency for said pulley to rotate said first valve past its valve-closed or valve-open position.

Claim 5

Apparatus according to claim 1 in which the line is connected at one end to the raisable member, passes around the pulley and is connected at its other end via tensioning means to an anchorage.

Claim 6

Apparatus according to claim 1 in which said first conduit includes means for providing a controlled leak from said bellows, said leak being sufficient to cause occasional actuation of said first valve.

Claim 7

A support appliance, such as a bed, having a head section which is raisable and lowerable with respect to an adjacent section using an inflatable bellows, said appliance including means for maintaining the head section in a predetermined raised position, which comprises; a bellows adapted to support said head section, a pressure source, a first conduit having a first valve therein and connected between said bellows and said pressure source, a second conduit having a second valve therein and connected between said bellows and said pressure source, said first valve including a rotatable conduit rotatable between a valve-open and a valve-closed position, a pulley frictionally engaging said rotatable conduit whereby rotation of said pulley in one sense rotates said rotatable conduit from said valve-open position to said valve-closed position but no further and rotation of said pulley in the opposite sense rotates said rotatable conduit from said valve-closed position to said valve-open position but no further, and a line connected to said head section and passed around said pulley in such a manner that if said head section falls from said predetermined position, said line rotates said first valve from a valve-closed to a valve-open position, there admitting pressurized air to said bellows and restoring the head section to its predetermined position.

Claim 8

A support appliance, such as a bed, having a head section which is raisable and lowerable with respect to an adjacent section using an inflatable bellows, said appliance including means for maintaining the head section in a predetermined raised position, which comprises; a bellows adapted to support said head section, a pressure source, a first conduit having a first valve therein and connected between said bellows and said pressure source, a second conduit having a second valve therein and connected between said bellows and said pressure source, said first valve including a rotatable conduit rotatable between a valve-open and a valve-closed position, a pulley frictionally engaging said rotatable conduit whereby rotation of said pulley in one sense rotates said rotatable conduit from said valve-open position to said valve-closed position but no further and rotation of said pulley in the opposite sense rotates said rotatable conduit from said valve-closed position to said valve-open position but no further, and a line connected to said head section and passed around said pulley in such a manner that if said head section falls from said predetermined position, said line rotates said first valve from a valve-closed to a valve-open position, there admitting pressurized air to said bellows and restoring the head section to its predetermined position.

Claim 9

A support appliance according to claim 6 which has a supporting surface for an occupant comprising a plurality of inflatable air sacs.