Patent GB-505755-A (GB)
Title: Improvements in or relating to vibratory electric motors
IPC: H02K33/02
Filed: 1937-10-12
Abstract: 505,755. Jigging-conveyers ; hoppers. WEYANDT, C. S. Oct. 12, 1937, No. 27699. Convention date, Oct. 21, 1936. [Class 78 (i)] [Also in Group XXXV] A vibratory armature motor for actuatiug conveyers and hoppers comprises an armature resiliently supported for unobstructed vibration and a magnet supplied through a static rectifier from a source of alternating current with current impulses separated by substantial periods of zero energy or small reverse current, the natural periodicity of the armature being lower than 'the periodicity of the current impulses. The natural periodicity of the armature may be between two-thirds and twenty-nine thirtieths of the recurrence periodicity of the pulsating current. As shown applied to the actuation of a conveyer, Fig. 1, a base 1 carries a laminated E-shaped electromagnet 14. Two side bars 28 at the ends of the core are threaded at their upper ends to receive nuts 31; 35 which can move spring supports 33 to adjust the tension of a spring 38 carrying the laminated armature 41. The armature is connected to one end of the base of the conveyer trough 52 by means of an angle member 45 and the other end of the trough is supported by a leaf spring 55. Increase in' weight on the motor deflects the springs to reduce the air gap between the armature and the magnet. The conveyer may be horizontal or inclined. The base 1 is mounted on vibration absorbers 5 which may be of the form shown in Fig. 5 comprising a channel-shaped, strip 6 secured to the base and angle plates 10, 11 secured to the floor and joined to the portion 6 by rubber pieces 8, 9. The free vibration period of the base 1 and absorbers 5 is the same as the natural vibration period of the conveyer mounting. The lower faces of the spring supports 33 may be curved in order that the natural vibration period. of the spring may be dependent on the amplitude of vibration. The same result may be obtained by the use of resilient materials such that the deflection under load is not proportional to the load, for example rubber or cast iron. The spring 55 may be replaced by another vibratory motor or two pairs of such motors may be employed. In a modification, Fig. 10 (not shown), the conveyer trough and the base are connected by laminated leaf springs, the leaves being separated by spacers to introduce a damping effect. One of the springs is adjustably connected to the base so that its lower end can be moved towards ur away from the other spring to vary the periodicity of vibration of the vibrator. When the apparatus is employed to vibrato another body, it is secured to such body without the interposition of vibration absorbers, Fig. 15 shows the invention applied to a hopper vibrator suitable for attachment to the apparatus described in Specification 470,491. A laminated core 169 of inverted T-shape is secured between two halves of a base 161 and carries a coil 173. An armature 184 is mounted at each end on resilient supports 175 similar to the vibration absorbers shown in Fig. 5. The heads of the securing bolts 194 may be coated with hard non-magnetic material, and surfaces 192 of the same material mav be located in the base below the bolt heads so that if contact occurs between these co-operating surfaces, wear is reduced and the shunting of flux is prevented. The rectifier may be of the thermionic or copper oxide type and may be shunted by a resistance to allow a small negative current to pass in the intervals between the main pulsations. The amplitude of vibration may be varied by changing the impedance of the circuit as by a rheostat. The Specification as open to inspection under Sect. 91 describes also constructions of hoppers and an electric circuit which are described in Specification 470,491. This subject-matter does not appear in the Specification as accepted.