GB1304923A - - Google Patents

Abstract

1304923 Walking beam conveyers NIPPON STEEL CORP 19 Feb 1970 [21 Feb 1969] 7941/70 Heading B8A [Also in Divisions F4 and G3] In a control circuit for a so called walking- beam type of conveyer, used for shifting ingots to a furnace, in which a piston drives the beam horizontally with a predetermined velocity characteristic for each stroke, the velocity characteristic can be altered when an ingot approaches the exit of the furnace so that it comes to rest at a predetermined position in relation to the ingot extraction equipment. In Fig. 3 a piston 1 operated by a servo-pump 9 drives the walking-beam (not shown) horizontally, and also a displacement encoder 4, the pulses from which are from the beginning of the stroke counted in a counter CA whose decoded output via stages 1-N provides a succession of N signals to accelerate the servomotor. The Nth signal remains constant for a predetermined number of displacement pulses thereafter, after which contact CR3 opens and the following displacement pulses are counted by a counter CB whose output via stages 1-N provides a succession of N signals to decelerate the servo motor and eventually end the stroke. The cycle is repeated until a photoelectric sensor senses an ingot approaching the furnace exit, whereupon contact CR4 feeds the pulses to counter CC, whose output via decoding stages 1-N is compared with the output of counter CA in a comparator 10. Upon equality or the output of counter CC being less than counter CA relay CR5" operates to control the servo-motor from the output of counter CC instead of counter CA, whereby if the photoelectric sensor operates during the acceleration period, the servomotor remains accelerating until the output of counters CA and CD are equal and then decelerates to a stop. If it is during the constant velocity period, control is immediately switched to the counter CD and if it is during the deceleration period deceleration proceeds normally and the piston is stopped only in the acceleration period of the next stroke.