Abstract: A tool support assembly having bi-directional position control. A tool support element is positioned within a housing and movable axially therealong in response to applied axial force F on a control element. A bi-directional positioning assembly links the tool support element to the housing and includes at least one detent element affixed to the housing and having at least one detent which extends transverse to the axis of the housing. The positioning assembly further includes at least one latch element captively positioned within the housing and selectively movable along the axis relative to the housing. The latch element includes at least one lock arm which is resiliently biasable toward one of the detents and is adapted for selective engagement therewith. A control element is captively positioned within the housing and is movable relative to the housing along the axis.

Abstract: Method and apparatus for analyzing a liquid such as blood, and in particular analyzing certain constituents such as potassium or calcium ions, or dissolved gases comprising withdrawing the constituents from the liquid into a carrier fluid, which may or may not be derived from the liquid itself and analyzing the carrier fluid. In this way, for example, the analysis apparatus is not contaminated by undesired constituents, such as protein molecules of the liquid under test.