Abstract: A camshaft has, for each valve lifter, a high lift cam between two low lift cams, the high lift cam fitting within the envelope of the low lift cams. The lifter comprises an outer tappet elongated in the direction of the camshaft and slidably mounted in an elongated bore in a cam carrier. The outer tappet is contacted by both low lift cams and operates two valves simultaneously. An elongated bore extending transverse of the outer tappet carries an elongated inner tappet which is contacted by the high lift cam. A hydraulically actuated locking mechanism couples the tappets for movement together for high lift operation and unlocks for low lift operation to allow the inner tappet to idle in the outer tappet.

Abstract: There is described a cartridge for receiving test elements sensitive to improper orientation. A key and keyway are provided on the inside surface of a wall of the cartridge and on the test element in an asymmetric disposition, so that test elements can be inserted only with a proper orientation.

Abstract: A compliant head loading mechanism for a thermal printer is disclosed which compliantly loads a thermal print head against a carrier and a receiver mounted on the platen to uniformly apply pressure across the width of the receiver.