Patent GB-1358160-A (GB)
Title: Recording apparatus
IPC: G01P1/12
Filed: 1970-07-03
Abstract: 1358160 Recording apparatus SMITHS INDUSTRIES Ltd 25 June 1971 [3 July 1970] 32418/70 Heading G1J A tachograph comprises four styli 31, 32, 33, 34 to provide, within four different chart zones, records against time of vehicle speed, distance travelled and respectively the functions of two crew-members, the styli being arranged so that no two chart zones have a common area and the styli 33 and 34 being prevented from concurrently providing records indicative of the function "driving". The four styli are spaced along a radius of a disc chart driven by clock mechanism (which may be electronic) mounted in a cover hinged to the casing 10 at 12 and locked at 80. The styli 33, 34 are mounted on levers 40a, 40b pivoted at 42a, 42b and concurrently driven by an electro-magnet 30 to vibrate independently with amplitudes limited by constraining levers 54a, 54b with pins 52a, 52b working in apertures 50a, 50b in the mounting levers 40c, 40b. Each lever 54a, 54b can be set by a vehicle crewmember to one of three positions D, W, R by an external arm 55a, 55b to select the portion of the aperture 50a, 50b to be engaged by its pin 52a, 52b, whereby the corresponding stylus 33 or 34 will be constrained to draw a wide band, narrow band or a line on the disc, Fig.6 (not shown), to record the durations of "Driving", "Work other than driving" and "Resting". To prevent both crew members setting their levers 55a, 55b to record "Driving" at the same time, each has a key to insert in the key hole 80, one capable of rotation clockwise, the other counter-clockwise, whereby a cam 75 is set by the member designated "driver" to stop a limb 62a, 62b of the lever 55a, 55b associated with the other member from being set to position D, the limbs 62a, 62b being linked by the engagement of spring blades (66) welded thereon with notches (68) in a horizontal casing part (69). When either crew member inserts his key, the electro-magnet 30 is energized by the consequential closing of contacts. Alternative arrangements envisage (a) contacts 72a, b closed by fingers 70a, b on to levers 54a, b, (b) contacts 74a, b closed by reduced parts 64a, b of the limbs 62a, b, (c) contacts formed by the notches 68a, b closed by the spring blades 66a, b welded to the limbs 62a, b or (d) contacts (82) closed by the cam 75. When a locking key is used in the key hole 80 a fifth stylus is vibrated by an electromagnet 86 to record locking or unlocking of the case 10. In the embodiment of Figs.7, 8 (not shown) another method of selectively restraining the amplitude of vibration of the styli 33, 34 is provided using three driving pins on each of two linearly reciprocable bars to allow selection of the effective' distances of the fulcra of levers supporting the styli 33, 34 from the selected driving pin. In either embodiment the records made by the styli 33, 34 when the vehicle is stationary can be made to distinguish periods when the engine is running by allowing some play of the driving pin in the appropriate portion of the aperture so that a thicker line is drawn due to vibration of the vehicle. The casing 10 is cast, the cam moulded from plastics e.g. Nylon and the levers 40a, 40b are made of mild steel.