| 摘要 |
981,225. Belt gearing; variable-ratio gearing. DIXI S.A. Feb. 21, 1961 [Sept. 5, 1960], No. 6249/61. Headings F2D and F2Q. [Also in Division B3] A drive from an electric motor 7 to a shaft 4 of an horizontal milling and boring machine comprises two co-operating belt drives 6, 5 arranged in series along two pivoted arms 8, 9 the arm 9 being adjustable in length by means of a screw sleeve 16 in order to vary the belt tension and hence to vary the natural frequency of vibration of the drive system. The shaft 4 is mounted in a spindle head 1 which is adapted to slide in a guide way 2 in the machine frame 3. The spindle head weight may be balanced by a spring 31 or by means provided within the machine frame 3. The shaft 4 is connected to a work spindle through two-speed toothed gearing, Fig. 4, and a torsionally resilient coupling 50 comprising coupling halves 50<SP>1</SP>, 50<SP>11</SP>, connected by pins 52 in rubber sleeves 53, the part 50<SP>1</SP> being coupled to a hollow shaft 44 by key 48. In a modification, pivoted links 32, 33 and a spring 31 are arranged as shown in Fig. 6. The two-speed gear comprises a double lever 56 which may be swung in one direction to engage dogs 35 on a pinion 34 with dogs 42 on a spur gear 41, for direct drive, and in the other direction to mesh pinion 34 with a spur gear 36 on an intermediate shaft 37 and to mesh a pinion 40 on shaft 37 with spur gear 41 for low speed drive. |
