Patent GB-882762-A (GB)
Title: Tachograph for vehicles
IPC: G07C5/12
Filed: 1959-09-25
Abstract: 882,762. Recording speed; timing work and rest periods of drivers. KIENZLE APPARATE G.m.b.H. Sept. 25, 1959 [Nov. 21, 1958], No. 32654/59. Classes 106 (3) and 106 (4). A tachograph for a motor vehicle has additional styli held out of contact with the record disc while the vehicle is running and blocked against fraudulent use in that position, the styli being movable to effective position by means of manually-operable switches, when the vehicle comes to a stand still. Recording takes place in that field of the record disc in which normally speed is recorded. Two styli are provided, one for each of two drivers, arranged to record in three different ways characteristic of waiting, working and resting periods, each type of recording being initiated by manually-operating a corresponding switch button or by appropriately setting a switch arm to a corresponding contact, there being a set for each driver, with an extra button or contact to operate when going off duty.  Means for moving the styli into and out of contact with the record disc, Figs. 8, 9 (not shown), are controlled by relays operated in one case when the ignition is switched on to retract the styli and in another case automatically by a speed controlled arm to move the styli into recording position when the vehicle stops. As shown in Fig. 2 the stylus carried by the arm 93 draws a broad trace 114 during periods when the first driver is waiting, e.g. for papers, it draws a narrower trace 115 when he is working e.g. loading and a fine trace 116 during pauses, i.e. resting periods. When the vehicle stops contacts 110 close, relay 111 closes contacts 112 and if the first driver sets his switch 80 with the arm 81 on contact 83, 84 or 85 (for waiting, working or pausing) relay 91 moves the framework supporting the stylus arm 93 to recording position and a line is drawn. The arm 93 oscillates with the heating and cooling of a filament 94. When the filament is cool, contact springs 100, 101 touch contacts 102, 103 and if the arm 82 rests on a contact 87 or 88 electric current will flow through the filament and as it expands on heating the spring 95 will cause the contact 100 or 101 to spring away and cut-off the current until the filament cools enough to switch it on again. As the feeler 96 is nearer the pivotal axis of the arm 93 than the feeler 97, the amplitude of oscillation will be greater when the contact 87 is selected for a waiting period than when the contact 88 is selected for a working period and no oscillation will occur when contact 89 is selected for a pause. Selecting contact 90 at the end of work releases relay 91 to stop recording. The second driver uses the switch 80<SP>1</SP> and similar records are made simultaneously through stylus arm 93<SP>1</SP>. An alternative method of recording is provided by the use of styli 120, Fig. 10, in which the wax coating of a record disc is melted by heat supplied to edges 131a and/or 131b by supplying current selectively to one or other or both of coils 128, 129 according to the setting of the switches. Control lamps indicate the actuation of the manually-operated switches.