GB1454948A - Device for continuously monitoring the operation of recording means in a tachograph - Google Patents

Abstract

1454948 Recording apparatus KIENZLE APPARATE GmbH 25 Nov 1974 [28 Nov 1973] 50877/74 Heading G1J To monitor that the recording means are in their correct operational state in a vehicle tachograph having at least one clock-driven record carrier 2, e.g. a diagram disc, and several styli 6 (7, 8) Fig. 3 (not shown) movable transversely over the record carrier and elastically mounted for movement normal to the record carrier, a pressure sensitive member is associated with at least one stylus to be actuable thereby through the record carrier 2 to pass an electrical signal dependent on the recording pressure of the or each stylus. As shown, the diagram disc 2 is supported on the rear face 3 of the tachograph lid 1, a recess 5 receiving the tips of the styli when no diagram disc is present. Next to the recess 5 are fixed electrical contacts 9, 10, 11 each spanning the transverse travel of a respective one of the styli 6, (7, 8). Over-lying the contacts 9-11 is the free end of a wide contact 12 of electrically conductive plastics foil which is inclined relative to the surface 3. A detector circuit Fig. 4 (not shown), lights a warning lamp if the contact 12 is not pressed against any of the contacts 9-11 by the action of the styli on the diagram disc. This occurs if there is no diagram disc, if the lid 1 is not properly closed, or if a stylus is sticking in its elastic mount. A tensional band may be used in lieu of the strip shown for the contact 12.