Patent GB-590292-A (GB)
Title: Improvements in or relating to magnetic suspension for electricity meter spindles
IPC: G01R11/14
Filed: 1945-04-17
Abstract: 590,292. Supply meters. FERRANTI, V. Z. DE., and FERRANTI, Ltd. April 17, 1945, No. 9557. [Class 37] A magnetic suspension is arranged to permit removal of the spindle and disc substantially without disturbance to the magnetic elements or circuit of the magnetic suspension. The magnetic suspension shown in Fig. 1 is attached to the spindle h on which the disc a is mounted and is detachable from the frame b of the meter. It consists of a cylindrical cage c having upper and lower cylindrical spaces separated by an internal circular ridge d. In the lower space is a permanent magnet disc f attached to the spindle h by being made a press-fit and riveting over the spindle end, a brass bush i being pressed into the end of the spindle. Alternatively, the magnet or bush may be screwed to fit on the end of the spindle. In the upper space of the cage c is a similar permanent magnet disc e, which is fixed by making it a press-fit, or by a removable retaining rim, or by a fixed retaining rim, the ridge d being removable to serve as a clamp. The magnet discs e, f are magnetized radially so as to attract one another. The upper bearing is constructed as a screwed stud j, the lower end of which is riveted to the upper magnet r and is fitted with a brass bush k serving to hold a bearing pin m, which enters the bearing hole in the bush i. A retaining ring g is screwed into the cage c and fixed by a grub screw g<1> after adjustment. The frame b of the meter has an integral bracket b<1> which is slotted to receive the stud j by frontal insertion and is also slotted horizontally to house a locating nut n having a radial arm n<1>. This fits into a socket and is secured by a grub screw o. To remove the rotor the upper end of the spindle is released by unscrewing the grub screw o, when the spindle with the stud j and magnetic suspension attached may be brought forward out of the slotted bracket b<1>. Instead of the bracket being integral with the frame it may be fixed by a screw p<1>, Fig. 2, and located by dowels p. The bracket b<2> is tapped to receive the upper bearing screw j and is split and fitted with a clamping screw b<4>. To remove the rotor the bracket b<2> is removed from the frame so that it comes away with the magnetic suspension unit attached to the end of the spindle. In a modification, Fig. 4, the magnetic suspension unit in its cage c is adapted to be secured to the frame band easily detachable from the spindle h by a bayonet joint s. The bracket b<1> is integral with the frame and is provided with a bush q which is adjustable on the upper bearing screw j and is a sliding fit in a cylindrical recess in the bracket, in which it is held down by a spring r. In another construction, Fig. 5, the lower magnet disc may be attached to the spindle h by a socket s<1> and grub screw s<2>. The bracket is arranged to permit upward movement by forming the bracket with a vertical slot for a fixing screw b<@6> and the frame with a vertical slot for the dowel bj. By loosening the screw the bracket may be raised for disconnecting the socket s<1> from the spindle h.