| 摘要 |
844,947. Making plate glass. GLACERIES DE LA SAMBRE S. A. March 26, 1957 [April 18, 1956], No. 9892/57. Class 56. In a plate-glass producing plant embodying rolling cylinders 3 and subsequent rollers 4 for conveying the ribbon through an annealing leer B, intermediate zone C, grinding and polishing mechanism D, washing, drying inspection, cutting and lifting zones E, F uni-directional drives 31, 31a are embodied in the transmission between the prime movers and some or all of the rollers. Such drives are provided at least for the rollers in those zones wherein breakage of glass is most likely to occur i.e. in the grinding and polishing zones. Each roller may have its individual uni-directional drive or several rollers may be grouped under one such drive. Two types of drives are illustrated, both in the nature of a free-wheel device, one 31, being a pawl and ratchet mechanism and the other 31a, a cam wheel with wedging rollers. The arrangements ensure that if an electrical or mechanical breakdown occurs in a prime mover, the rollers normally rotated by such mover can continue to rotate freely under the glass ribbon which is still being advanced by the other rollers; this prevents damage to such rollers and also prevents the ribbons piling up or breaking on the rollers which would otherwise be stationary. The whole lay-out is described with reference to a variable-speed system embodying a Ward- Leonard set (A.C. motor 46, exciter 48, rheostat 48<SP>1</SP>, D.C. generator 47) controlling the voltage to D.C. motors 50, 51, 52, 57, 61, 65 having field rheostats 50<SP>1</SP> . . . 65<SP>1</SP>. The motors 50, 51, 52 drive their free-wheel devices through reduction gear 53, 54, 55, and the motors 57, 61, 65 drive and form part of frequency changer sets including alternators 58, 62, 66 controlling A.C. motors 59, 60, 63, 67 associated with reduction gear driving their free-wheel devices. Specifications 721,024 and 739,796 are referred to. |
