Abstract: A unitarily molded control knob for an irregularly shaped rotatable shaft, such as a D-shaft. The knob has a molded flat floor which engages the flat of the D-shaft, and two opposed arcuately concave side walls which engage the opposite arcuately convex sides of the D-shaft adjacent the flat. A resiliently flexible cantilever arm is spaced opposite from the flat floor and biases the shaft tightly against the flat floor as the shaft is inserted axially therebetween. A major length of the underside of the cantilever arm is arcuately concave to mate with the area of the D-shaft opposite the flat and terminates in a flat area on the free end of the cantilever arm to distribute the pressure on the D-shaft and to develop a more positive gripping action with better holding capabilities.

Abstract: The disclosure relates to a selectively operable power supply for a recording system of the type which includes tuning and intermediate frequency sections for receiving and converting transmitted television signals into composite video and audio signals and a recorder for recording the composite video and audio television signals onto a recording medium. The power supply comprises a timer including a switch which is selectively operable for providing an A.C. line voltage when its contacts are closed at preselected times and a receptacle coupled to the switch and adapted to receive the power input of the recorder for powering the recorder at the preselected times and a rectifier and filter coupled to the switch for powering the tuning and intermediate frequency sections with filtered DC voltage at the preselected times.

Abstract: For a motion picture projector, a mode controller is coupled through control members to a dual clutch assembly to selectively transmitted drive as required from a unidirectional input to supply and take-up devices. Particularly, the mode controller is a manually operable mode selector for adjusting a control rod carrying dual control cams to selectively actuate respective supply and take-up drive transmitting clutches to free, slip, and positive drive conditions, as well as to actuate other projector components. Responsive to conditioning of the clutches, and projector components such as shuttle retractor and other control mechanisms, the projector is changed from one mode of operation to another.

Abstract: A film strip projector which is provided with synchronized audio accompaniment. A film strip is framed with respect to a projection aperture by a selectively operable framing device. Once the film strip is initially framed, the film strip is advanced frame by frame by a Geneva type film advance mechanism. The audio accompaniment is carried on a dual track audio tape, one track of which carries the audio message pertinent to a particular frame and the other track of which carries a control signal for the film drive mechanism. All of the operative components of the film transporting mechanisms are mounted on a unitarily molded chassis. The chassis includes features for mounting a set of optics for easy removal and cleaning.