Abstract: The specification discloses a slide mount which may be used in a conventional slide projector enabling the film transparency to be rotated during image projection. More particularly, the mount comprises a body to be stationarily supported in the projector and a film-supporting assembly rotatably supported by the body. The film-supporting assembly is engageable at one edge of the body by a rotatable driving mechanism. Preferably, the film-supporting assembly is registered against the body in a direction perpendicular to the film to provide critical focus for the film.

Abstract: A reference light beam projector of the type which produces a modulated plane of light for use as a reference in many different applications such as for aligning railroad tracks. This modulated reference plane is formed by projecting a collimated light beam along a predetermined path and providing means for variably refracting the beam so to effectively variably bend the beam back and forth along a plane. Specifically, the means for variably refracting the beam is a rotating optical element comprising a window through which the beam is transmitted and variably refracted as the optical element is rotated.

Abstract: A locking member is positionable within an opening in the arm and is likewise engageable with a post and slidable jointly with the arm along the axis of the post to initiate a clamping force. A shaft having a handle assembly on one end is threadable in the locking member and hand rotatable to move the locking member laterally relative the post to secure the arm and post together at selected positions relative each other. A spring means in the handle assembly provides increased turning torque as the lock is tightened and at a preselected designing load, a brake member overrides the washer to prevent further hand tightening.

Abstract: A vertically oriented bellows has a fixed plate at one end and a movable plate at the other end. As air flows into the bellows, the movable plate pivots relative to the fixed plate and the free end thereof is cooperative with a readout panel to indicate the volume of the bellows. The plates are interconnected by an adjustable spring urging the plates toward each other when the bellows are expanded to simulate lung compliance. Selected tubes having calibrated flow characteristics interconnect the bellows to a lung ventilator to simulate lung resistance. Preferably, a pair of bellows are arranged in mutual association together to simulate a pair of lungs in order to analyze their interdependency.