GB812218A - Improvements in alarm devices for tachographs - Google Patents

Abstract

812,218. Alarm devices for tachographs. V.D.O. TACHOMETER WERKE A. SCHINDLING G.m.b.H. Jan. 15, 1957 [Jan. 26, 1956], No. 1538/57. Class 106 (3). [Also in Group XXXVII] A contact device for tachographs that can be set to give warning signals at particular vehicle speeds comprises an insulating block 1 having some first contact rails 2 secured thereto, second contact rails 4 parallel with the first rails 2 and slidably mounted on the block 1; spring contact wiper blades 16a, 16b on the speed writing lever 12 supporting the pen of the tachograph, said wiper blades each serving to complete a circuit between one of the fixed contact rails 2 and one of the movable contact rails 4; and means for adjusting the positions of the movable contact rails 4 in relation to the fixed contact rails 2 whereby the contacts giving the warning signal can be adjusted in accordance with selected or prescribed speeds. The rails 2 are longer than the rails 4. The adjusting means comprises a disc 17 on a shaft 7 carrying a pinion 5 meshing with teeth on the lower contact rail 4, and a disc 18 on a coaxial shaft 8 carrying a pinion 6 meshing with teeth on the upper sliding rail 4. The shafts 7 and 8 are coupled together by a pin-and-slot device 19 or by frictional means such that if no axial pressure is exerted on the shaft 7 both shafts must rotate together but if the shaft 7 is depressed against spring means 20 the coupling 19 is released and the shafts can be rotated independently. The device may be arranged to give an optical signal when a first speed is exceeded and an acoustical warning when a higher speed is exceeded.