Patent GB-1397353-A (GB)
Title: Recording device in tachographs
IPC: G07C5/00
Filed: 1973-10-04
Abstract: 1397353 Recording apparatus KIENZLE APPARATE GmbH 4 Oct 1973 [11 Oct 1972] 46423/73 Heading G1J The writing mechanism of a vehicle tachograph has at least one stylus 27 for automatically recording periods of different significance as distinguishable traces, and rotary input movements fed to a comparator gear 9, 10 control the latter to select the pattern of trace produced by the stylus. The comparator gear Figs.1,3 comprises a gear-wheel 10 axially slidable and freely rotatable on a shaft 9 between two compression springs 25, 26, a diametral pin 24 through the shaft 9 being engageable with a helical groove 23 in the central bore of the gear 10. The gear-wheel 10 is driven via a gear train 17, 14, 13, 12, 11 from a continuously running electric motor 16. The shaft 9 is driven via a gear train 20, 19, 18 from the speedometer or odometer drive, or from a motor 21 energized by pulses produced in dependence on vehicle movement by a tachogenerator 22. With the vehicle stationary, the rotating gear-wheel 10 engages the stationary pin 24 and is moved rightwards, Fig.1, until the pin 24 slidably engages the left face of the gear-wheel, as shown. When the vehicle starts to move, the motor 21 rotates the shaft 9 in the same direction as the gear-wheel 10 is rotating. At a predetermined vehicle speed, e.g. 25 km/hr, the gear-wheel 10 and shaft 9 have the same rotational speed. At higher vehicle speeds the wheel 10 is moved to the left, Fig.1, of the pin 24. Trace selector. In Fig.1, the stylus 27 is positioned to produce a trace 28 when the vehicle is stationary and a trace 29 when it is moving, by a lever 4 pivoted at 3. One end 7 of the lever presses against the side of gear-wheel 10, and the other end has a cam slot 6 engaged by a pin 5 on the stylus arm 1. In a modification, Fig.2, a manually set knob 44 is connected to the lever 4 via a lever arm 47 and a spring 48. A continuously rotating eccentric cam 31 is resiliently connected to the stylus arm 1 via spring calipers 32, 33 and a pin 34 on the arm 1. The pin 5 on the stylus arm engages a gate 34 in the lever 4 so that with the driver on duty and driving, a wide bar trace 36 is produced. With the knob at P (pause) and vehicle stationary a line trace 37 is drawn. With the driver on duty and loading, unloading, or doing repairs, (knob 44 at A) a narrow bar trace 40 is drawn, while with the driver on stand-by, i.e. acting as co-driver and not in charge of the vehicle, (knob 44 at B) a narrow bar trace 41 is drawn. In a practical embodiment, Fig.3, the lever 4 is mounted on a shaft 57 on which a fork 56 engaging the sides of the gear wheel 10 is rotatably and slidably carried. Springs 25, 26 act between the gear-wheel 10 and discs 59, 58 respectively, the discs being secured to the shaft 57, so that the fork is resiliently connected to the shaft 57 to move the lever 4 axially. The lever 4 has cam surfaces formed in two planes, Fig.4 (not shown), which are effective for rest and motion of the vehicle. The motor 16 also drives the eccentric cam 31 which can oscillate the stylus arm 1 via a resilient lever 71 and the shaft 2 or 72. The mechanism may selectively drive one or other of two stylus arms to give traces for one or other of a pair of drivers, Fig.5 (not shown).