Patent GB-409300-A (GB)
Title: Improvements in or relating to optical projection apparatus
IPC: G03B23/10
Filed: 1932-10-25
Abstract: 409,300. Clocks. NAYLOR, J. P., and NAYLOR, K. R., 57, Croxted Road, Dulwich, London. Oct. 25, 1932, No. 29840. [Class 139.] Optical-projection apparatus of the kind adapted to project the image of a timeindicating device such as a clock-dial and hands, or the hands alone, upon a screen simultaneously with the projection of pictorial matter is characterised in that the time-indicating device is actuated by a synchronous electric motor. As shown in Fig. 1, the synchronous electric motor A drives by means of the shaft B<1> and gear box BA, a shaft G carrying the slide carrier disc Q and a pinion BB meshing with an idler JK transmitting motion to the gear rings MN carrying the clock hands. The gear box BA carries a support BD holding a projection lens mechanism BE. The lamphouse BL contains a lamp BC, and a condenser BF is located in the heat insulating space BM provided between the walls of the lamp-house BL and the mechanism-house BK. The pictures are projected through a window BH in the door BJ. A fuse-box BN is provided, and the lamp-house has a hinged door BM<1>. As shown in Fig. 3, the motor A is coupled to a worm B engaging a worm wheel C coupled by the shaft DC to a pinion D meshing with a wheel E carrying a cam F loosely mounted as one unit with the wheel E on the spindle G. A spring H is attached to the cam F and the spindle G, the pins T of which engage a pallet U. The wheel E also meshes with idlers J and K, pivotally mounted on an arm L, which permits one or the other idler J, K to engage with the wheel E and the hand-carrying ring M to permit of the reversal of the rotation of the hand-carrying rings M, N. The rings M, N are supported by rollers I, the minute hand ring N being geared to the hour-hand ring M by a 12 to 1 gear train P. The hands O, O<1> are introduced into the optical beam so that an image thereof is projected. The slide carrier Q has a series of apertures R<1> provided with means to hold slides and is secured to the spindle G, the opposite end of which carries the disc S furnished with two series of pins T, T <1> on opposite faces thereof, which pins engage the pallets U, U<1> supported by the pivots AU and operatively connected by an arm V with a cam wheel F. Rotation of the wheel E causes rotation of the cam F to tension the spring H, a pin T presses on the pallets U and the cam F causes the arm V to move the pallet U through an angle sufficient to release the pin T, when the disc S rotates under tension of the spring H until arrested by the pallet U<1> engaging the next pin T <1>. Stepwise movement of the slide carrier Q is thus obtained. The electric lamp circuit is provided with a mercury switch W held by the carrier X, pivoted at X<1>, and having an arm Y engaging a cam AA driven by the hour hand ring M through the idler AC and gear wheel Z. A change speed gear mechanism may be provided. In a modification two electric motors are provided, one to drive the handcarrying gear rings and the pallets and the other to drive the scape disc and the slide-carrying disc. In another modification, one motor operates the time indicators and the other the slide-carrying disc, which is itself provided with the pins, dispensing with a separate scape disc, the operation of the two motors being entirely independent.