GB773545A - Improvements relating to clutches for transmitting rotary motion - Google Patents

Abstract

773,545. Magnetic clutches. S.S.S. GEARS, Ltd. Aug. 10, 1955 [Aug. 23, 1954], No. 24522/54. Class 35. [Also in Group XXIV] A Legge clutch of the type disclosed in Specifications 354,711 and 410,083, [both in Group XXIV], comprising a toothed clutch ring 1 on a shaft 2 and an intermediate toothed clutch member 8 helically splined at 7 on a shaft 6, is provided with means by which the engagement of the clutch teeth is initiated by magnet force. In the form shown, a number of U-shaped permanent magnets 5, Figs. 3, 4, are carried by the shaft 2, and the intermediate clutch member 8 carries a notched armature ring 15 and a copper eddy current ring 16. The magnets 5 exert an axial force to the left of Fig. 3 on the armature ring 15 &c., tending to engage the clutch teeth. When the shaft 2 rotates more quickly than the shaft 6, the clutch teeth are in nuzzling engagement and slide freely over each other, while a drag torque produced by the magnetic interaction of the magnets 5 with the armature 15 and eddy current ring 16 tends to oppose the axially directed magnetic force by screwing the intermediate clutch member 8 to the right on the shaft 6. As the speed of the shafts 2, 6 approach synchronism, the drag torque ceases, and the clutch teeth are drawn into initial engagement by the axial magnetic force. Mechanical interaction, as the speed of the shaft 6 increases beyond that of the speed of the shaft 2, then screws the clutch member 8 to the left to fully engage the clutch teeth. If the speed of the shaft 6 decreases below that of the shaft 2, the intermediate clutch member 8 is screwed to the right to disengage the clutch teeth. In one modification, Figs. 1, 2 (not shown), an unnotched armature on the intermediate clutch member carries the copper eddy current ring. Alternatively, electromagnets may be used in place of permanent magnets.