Baxter International Inc.

Puritan-bennett Corporation

Grigor Sarian

Jeff Duncan

James K Bullock

Barry R Crandall

Dee J Neville

A control circuit for a fluid-filled heating pad is described. The control circuit is unique in that it includes a thermistor that is located in close proximity to the heating pad. The circuit is also unique in that it includes a single high-precision reference resistor to self-calibrate the control circuitry.

Temperature control device for fluid filled pad

An insulated housing is described which includes a means for holding a pair of electrical connectors in parallel. The housing includes a griping means which allows a person to either insert or remove the housing from a mating electrical connection. The housing also includes a 'living hinge' which, when closed, clamps on to the pair of electrical connectors to provide strain relief.

Hinged electrical connector

A pressure switch having a movable bellows (14) in a pressure chamber (12), a first electrical contact (16) movable with the bellows, a three-dimensional cam (18) and a second electrical contact (20) resiliently biased to follow the cam. In the preferred embodiment of the invention, the cam has a radius that linearly increases with the angular position of the cam, and is tapered toward one end for all regions about its periphery except at a point of maximum radius. Calibration at low pressure is effected by rotating the cam to its maximum-radius point, applying a standard low pressure to the chamber (12) and rotating the chamber about a threaded coupling (26) until the contacts (16) and (20) are at the point of closing. Calibration at high pressure is effected by rotating the cam to its minimum-radius point, applying a standard high pressure to the chamber, and adjusting the axial position of the cam until the contacts are at the point of closing. After such calibration, no recalibration is needed for intermediate pressure settings of the cam.

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Los Angeles, CA, United States of America

Grigor Sarian