GB744786A - Doffer comb device - Google Patents

Abstract

744,786. Oscillating rotors. JOHNSON & JOHNSON. Sept. 9, 1954 [June 9, 1953], No. 15891/53. Class 35. [Also in Group IX] A doffer comb is carried by a rotary element displacement of which in both angular senses from a static equilibrium position is resiliently resisted by an anchorage, and rotary oscillation of which about the equilibrium position is urged by electromagnetic means which is energized by alternating or intermittent frequency corresponding to the natural frequency of vibratory oscillation of the system comprising the element, comb, and anchorage, whereby in operation the system is maintained in vibratory oscillation by the energizing means supplying the energy required for the work and for overcoming damping due to natural energy losses. The device shown in Fig. 1 comprises a comb shaft 1 freely mounted in bearings (not shown) and connected to a torsion bar 2 held by a clamp 3 and carrying by means of arms, as at 4, a doffer comb 5: the shaft 1 carries a permanent magnet 6 the pole-pieces 7, 8, of which each oscillate across and pass through gaps 10 in pole pieces 11, 12, of a horseshoe laminated electromagnet 9 (only one shown) the energizing coil (not shown) of which is connected to an alternating current supply, Another embodiment, Fig. 2, comprises a freely mounted comb shaft 20 connected to a torsion bar 21 held by a clamp 22 and carrying by means of arms 23 a doffer comb 24: the shaft 20 carries a plate 25 having studs 26 carrying a laminated electromagnet 27 mounted within a stationary energizing coil 28 connected to an alternating current supply: the magnet and coil 27 and 28, Fig. 3, are mounted within soft iron pole-pieces 31, 32 of a permanent magnet 33. It is stated that when used with a 50 cycle alternating current supply the electromagnetic device achieves about 3000 oscillations per minute.