Abstract: The present invention is a device to measure the parallel shear force on a mattress. The device has a motor, a weighted object, a high friction material pad, and a load cell. The motor moves by pushing and pulling the weighted object on the high friction material pad which is on the mattress. The load cell measures the peak shear force when the weighted object is pulled and when the weighted object is pushed.

Abstract: A mattress wherein at least one fabric strip bridges a foam crib for an inflatable cushion to provide lateral stability thereto such as when the mattress is tilted for turning a patient over or otherwise. The fabric strip position is selected so as not to interfere with pressure relief to a portion of the patient's body where pressure ulcers frequently occur. In order to accurately and quickly monitor the tilt of a mattress, transmitting and receiving coils are provided on opposite sides of an assembly of lifting bladders for the side of the mattress being lifted, and the signal strength is measured when a signal is transmitted therebetween, and the angle of tilt is determined therefrom. In order to reduce exposure of lines leading to an inflatable mattress, a notch is provided in a crib for receiving a pump for pressurizing a cushion within the crib so that the pump is positioned to face exteriorly of the crib to allow heat dissipation.

Abstract: An inflatable air pad, or fluid impervious pad, is provided having three layers, the top and bottom being joined together to form an enclosed envelope with a middle layer interposed between defining an upper and lower chamber. Fluid is allowed to flow from one side of the middle layer to the other, such that there is uniform pressure throughout. A sealable port is provided in the enclosed envelope for the injection of fluid under pressure. The middle layer is attached to the top layer in a series of seals or attachment points in a rectangular array and is similarly sealed to the bottom layer in a similar rectangular pattern; however, the two patterns are positioned 180 degrees out of phase with each other. These patterns form a series of small cushion areas in the upper and lower chambers respectively and the cushion areas are nested within each other on an offset basis.