Patent GB-723820-A (GB)
Title: Improvements in or relating to apparatus for indicating speed for a vehicle
IPC: G01P1/10
Filed: 1952-07-16
Abstract: 723,820. Moving and changing signs, road traffic signs. REAR-GUARD ASSOCIATES, Inc. July 16, 1952 [July 23, 1951], No. 1798152. Classes 3 (1) and 3(2). [Also in Groups XIX and XXX] An apparatus for indicating the speed of a vehicle, comprises electric signal means adapted to be mounted on a vehicle so as to be visible by an observer behind the vehicle for producing movement of a signal light back and forth along an arcuate path so as to obtain a zigzag effect, and speed responsive means connectable to and adapted to be driven by the vehicle for energizing said signal means whenever the speed of the vehicle is less than a predetermined value. A centrifugal type speedometer 25, Fig. 2, is arranged to actuate a switch 43 when the vehicle speed falls below a predetermined upper value and a switch 44 when the vehicle speed falls below a predetermined lower value. The switches 43, 44 are connected in circuit, as shown in Fig. 6, with an electric motor 76 of the oscillating type and three groups of lamps 64, 66, 72 contained in a casing 26, Fig. 5 detachably secured to the rear of the vehicle, Fig. 1 not shown. The lamps 64, 66 Fig. 5 are positioned behind windows 61, 62 covered by differently coloured lenses 65, 67 bearing respectively the inscriptions "Slow", "Stop". The lamp 72 is positioned behind an arcuate window 63 having a lens 71 and is carried by an arm 73 pivoted on a shaft 75 connected through gearing to the motor 76. A hood structure 80 surrounds the windows 61, 62. In operation when the vehicle speed is between the predetermined upper and lower values the switch 43, Figs. 2 and 6, is actuated to energize the lamps 64 via the contacts 47, 48 of the switch 44 and the motor 76 so that the signal "Slow" is illuminated and the arm 73 is oscillated so that the lamp 73 goes back and forth in an arcuate path behind the window 63. When the vehicle speed falls below the predetermined lower value the switch 44 is actuated to close contacts 47, 49 so that the lamps 66 and the motor 76 are now energized. The signal "Stop" is thus illuminated and the lamp 73 is still moved back and forth. The casing 26 carries a reel 56,for receiving the electric cable 27 connecting the casing to the speedometer so that when the vehicle stalls the casing 26 may be detached and placed on the road some distance behind the vehicle to serve as a warning signal for approaching vehicles. The lamp 72 and the arm 73 may be replaced by an arcuate series of lamps 86-91, Fig. 7, connected to contacts 97- 106 over which a wiper 96 is driven by the motor 85 when energized. The arrangement is such that the lamps light in the sequence 86, 87 ... 91, 90 ... 86, 87, &c. In another embodiment as applied to a train for example, the speedometer 121, Fig. 9 of any suitable construction and the indicating means comprising lamps 142, 143 are contained in the casing 120. The lamps 142, 143 are positioned behind arcuate windows 138, 139 covered by different coloured lenses 140, 141 and are carried by an arm 125 carried by a shaft 126 oscillated by an electric motor. The arrangement is such that when the vehicle speed is between the said upper and lower predetermined values the switch 162, Fig. 12, is closed to energize the motor 136 and the lamp 142 the latter via the contacts 164, 165. The arm 125 is oscillated and the lamp 142 moved back and forth in an arcuate path behind the window 140. When the vehicle speed is below the predetermined lower value the contacts 164, 166 are closed to energize the lamp 143 and the motor 136. The arm 125 continues to oscillate and the lamp 143 moves back and forth along an arcuate path behind the window 139. Pilot lights 170, Figs. 9 and 12, afford an indication of the correct operation of the systems.