| 摘要 |
913,102. Ball mills. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Jan. 21, 1960 [Jan. 22, 1959; May 30, 1959; July 18, 1959 (2)], Nos. 2365/59, 18512/59, 24772/59 and 24773/59. Class 59. [Also in Groups XXIV and XXXII] The high-frequency vibratory forces transmitted to the foundations by vibratory ball mills are reduced to a minimum by arranging the mills 1-4, Fig. 1, in groups of four, symmetrically disposed and interconnected by highfrequency leaf-springs 5... 8 tuned to the resonant frequency and arranged so that each mill is excited in anti-phase with the opposite mill. The sytem is supported on softer lowfrequency coil-springs 20 attached to the bed 21. Pairs of leaf-springs 9, 10, Fig. 2, of each assembly 5 ... 8 are attached to blocks 12 at the ends of each mill and are mutually connected by blocks 11 at their mid-points. Excitation . may be through eccentric weights 14 driven from a common motor through four universally jointed shafts 16. Excitation by a poly-phase electromagnetic system is also referred to. Photo-electric detectors 50, 52 are arranged to control the degree of excitation so that the movement of the vibratory parts is limited.
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