Patent GB-322913-A (GB)
Title: Method and apparatus for recording the passage of vehicles past a given point
IPC: G08G1/017
Filed: 1929-08-31
Abstract: 322,913. Murray, W. Aug. 31, 1929. Road - vehicle signals. - A method of and apparatus, for use in the. identification of motor vehicles travelling at an excessive speed past a certain point consists in photographing the vehicle by means of a camera operated by the passage of the vehicle. In the form shown in Fig. 1, a compressible air chamber a, placed across the roadway, is held in an expanded position bv means of springs b and communicate with a vertical chamber c having a series of pivoted switch members c<1> and containing a piston d and ball c, the ball being thrown up on compression of the chamber a to complete the electric circuit through a selected switch c' in a manner similar to that described in Specification 313,371. The electric circuit includes an electromagnet adapted to operate the shutter of a camera as shown in Figs. 2 and 3. The camera comprises a box 1 with spools 2, 3 carrying a film passing over guides 2<a>, 2<b>, a pivoted shutter 10 and operating mechanism therefor, and a feed mechanism for the film strip. The spool 3 carries a disc 5 with teeth 5<a> adapted to be engaged by a latch 6 and to be released therefrom to permit a weight 9 on the end of a sprocket chain 8 to effect the rotation of the spool 3 to advance the film. The shutter 10 is mounted on a. pivot 11 and has an aperture 10<a> which in one position registers with an aperture 12a in a partition plate 12. The shutter 10 has projections 13a, 13b coasting with a lever 14 and pivoted latches 15<a>, 15<b> to hold it in one or other of its extreme positions. An extension 20 of the shutter is slotted to receive a pin to which is attached the ends of springs 18, 19 surrounding a sliding rod 17 provided with studs 17<a> for co-operation with the latches 15<a>, 15b. The lever 14 has one arm connected to a spring controlled rod 23 operatively connected to a crank arm 22 on the axis of the armature of an electromagnet 21. When the electromagnet is energized by completion of the circuit through one of the switches c<1> the armature is rocked and through the link 23 rocks the lever 14 to release the shutter which through the spring 18 is rocked to its lowest position being held by the latch 15b. On the continued movement of the armature the lever 14 engages the arm of a bell crank lever 25 and through a link 27 and lever 26 trips the latch 6 to release the spool 3 which rotates through half a revolution under the influence of the weight 9. At the same time a crank arm 30 on the spool 3 through a connecting link 29 actuates a bell crank lever 28 connected to the upper end of the rod 17 whereby the rod is depressed a. sufficient distance to compress the spring 19 to an extent equal to that to which the spring 18 was compressed. The pin 17<a> releases the latch 15<b> and the shutter is held only by the lever 14. The duration of the exposure may be regulated by an adjustable friction member 32 rubbing against the shutter guides. The time at which the photograph is taken may also be recorded by placing a clock with a large " seconds " hand within the range of the camera. If a large number of photographs is desired a film container with a large supply of films is provided on the camera the film strip being guided over the spools 2, 2<a>, 2b and 3 in its passage from the supply to the receiving roller. The apparatus may be duplicated at stated intervals along a roadway and may also include an electric bell to give a signal when the speed of the passing vehicle is excessive. A hand-operated switch may be provided whereby a photograph may be taken at any time.