GB494051A - Improvements in eddy current speedometers - Google Patents

Abstract

494,051. Speedometers. HASLER AKT.-GES. WERKE FUR TELEPHONIE UND PRAZISIONSMECHANIK. Sept. 3, 1937, No. 24132. Convention date, Sept. 8, 1936. [Class 106 (iii)] An eddy current speedometer has a magnet system rotating with the driving shaft and axially adjustable to vary the magnetic field in the air gap between an armature member and the magnet system in which a non-magnetic eddy current drag member under spring control is situated. In the construction shown in Fig. 1 the magnet 9 is carried by a diamagnetic ring 4 having a spring-controlled slidable but non-rotatable engagement with the driving shaft 1 and supported by a ball-bearing 5 on a ring 6 screwed into a collar 7 and axially positioned therein by a worm 23 rotatable from outside the casing 21 of the speedometer and engaging with a toothed ring 22 provided on the flange 8 of the ring 6. The arbor 14 of the speed indicating needle 13 is supported on a bearing journal 17 let into the upper hollow end of the shaft 1 and resting on a helical spring 16. In the construction shown in Fig. 2 the driving shaft 1 is axially adjustable together with the magnet system 9 by means of the bearing tube 51 having a screw-threaded engagement in the neck 2<1> and axially adjustable by a worm 23 rotatable from outside the casing of the speedometer and engaging with a toothed ring 22 on the tube 51. The tube 5<1> can also be turned through recesses 24 at its lower end. The ring 4<1> carrying the magnet system 9 is keyed to the shaft 1 and the needle arbor 14<1> is adjustably mounted by means of a pin 14a in a bearing 17 countersunk in the upper end of the shaft 1.