GB340959A - Improvements in tachometer jewel frame and drive shaft retainer - Google Patents

Abstract

340,959. Eddy current speedometers. A.C. SPARK PLUG CO., Flint, Michigan, U.S.A. May 31, 1929, No. 16852. Convention date, Feb. 16. Void [Published under Sect. 91 of the Acts]. [Class 106 (iii).] An eddy current speedometer comprises a casing 7, frame 9, C-shaped magnets 11, 15, rotor shaft 33, spider rotor 31, and drag disc 18. The magnet 11 is held in position by rivets 11<1> and the magnet 15 by means of a crescent-shaped jewel frame 13 kept pressed against the magnet 15 by means of studs 10, 10<1> and clamping plates 20 and by means of the compensator 23, clamp 20 and stud 101. The four studs 10, 10<1> are diametrically positioned and the two studs 10<1> lengthened to secure the speedometer to its support. The drag disc 18 is attached to a spindle 17 journalled at one end in the rotor shaft 33 and journalled at the other end in a radial arm 14 of the jewel frame 13. The spindle 17 has associated with it the usual hair spring 23<1>, regulator 16 a n d indicating pointer 45. A retaining member 25 for the rotor shaft 33 is seated in a recess in the bottom of the frame 9, to which it is secured by rivets 28, and extends into an annular groove 27 of shaft 33. A magnetic calibrating member 24 is fixed over the clamp 20 retaining the compensator 23 in position and can be bent for calibration purposes.