| 摘要 |
982,512. Variable-slip clutches. GENERAL TIME CORPORATION. Nov. 18, 1963 [Nov. 20 1962], No. 45494/63. Headings F2C, F2D and F2L. [Also in Division D1] A constant speed driving arrangement for a knitting machine (see Division D1) includes an electromagnetically operated variableslip disc clutch, of which one of the discs is formed with a series of radial grooves serving for the passage, under the effect of centrifugal force, of oil to provide a shear film between the faces of the discs and for cooling purposes. In the arrangement shown the driving shaft 24 carrries a rotor in the form of annular pole members 135, 136 separated by a non-magnetic annulus 137, and with an outer annulus 143 to which a ring of friction material 145 is secured. The actuating solenoid 165 is mounted within a U-sectioned magnet 160. The armature disc 150, in which the sharp-edged radial oil slots 171 are provided, is splined to a hub member 151 secured to the driven shaft 26. The clutch casing is half filled with oil which, as the clutch rotates, is drawn through an annular passageway 181 between the magnet 160 and the hub 131 carrying the rotor disc, through a series of holes 182 in the latter, from which it passes to the radial slots 171 in the armature disc 150. The oil is cooled by the passage of air from a fan 185 on the driving shaft 24 over ribs 101, 102 on the exterior of the clutch casing. Clutch control.-The driven shaft 26 has an associated tachometer generator 190 in a control circuit, Fig. 9, connected to two of the supply lines L 2 , L 3 for the main drive motor M, the circuit including a step-down transformer 200, bridge rectifier 210 and filtering capacitor 204. The output from tachometer 190 is converted to an A.C. feedback voltage through a bridge rectifier 230, and a selectable reference voltage is provided from a voltage source 210 regulated by potentiometers 215, 217. The tachometer and reference circuits are connected in parallel to the input terminal 236 of an amplifier stage including transistors 241, 242 in series with the clutch actuating coil 165, so that any unbalance in the circuits due to clutch speed variation results in automatic variation of coil current to restore the clutch to the desired speed. U.S.A. Specification 2,422,568 is referred to. |
