Abstract: A desk top card file includes an elongate one piece base having an arcuate longitudinal profile. File cards are releasably carried by a pair of parallel longitudinal rails attached to the base. An end plate is hinged to each end of the base. The end plates are movable from a substantially parallel vertical orientation where they compact a stack of cards when the card file is not in use, to an open position, rendering the individual cards accessible for selection and reading. The hinges carry a resilient friction restraint which maintains each end plate at a selected angle. Variable friction forces determined by the profile of cam surfaces of the end plates minimize wear of the friction restraint while maintaining adequate retention forces on the card stack. The file includes a pivotable stand which is mounted to the underside of the base at one end and is opened to tilt the file toward the user.

Abstract: An improved membrane cap assembly is provided for polaragraphic oxygen sensors in which a preassembled cap is provided with a membrane mounted for receiving the electrodes thereagainst when the assembly is mounted on the sensor body in such a way that the secured portions of the membrane may slide or move in the secured state to accommodate or receive the electrodes. This has the effect of preventing destructive tension forces against the fragile membrane. Also, because of this arrangement, a more effective quantity of electrolyte is retained by the membrane adjacent the electrodes. This, in turn, has the effect of increasing the life of the assembly prior to electrolyte depolarization, and reducing the times necessary to dismantle and replace the assembly with a new cap, and a fresh quantity of electrolyte.