GB890649A - Mixing machines - Google Patents

Abstract

890,649. Switching systems. TRIANCO Ltd. Sept. 17, 1958 [Sept. 5, 1957], No. 28104/57. Class 38 (4). [Also in Groups II and XXXVII] The control system of a concrete mixer as described in Specification 883,434, in which the operations of raising the materials, mixing, watering and emptying are performed automatically in accordance with a predetermined time-cycle, is modified so that the machine can run continuously, or stop after the end of one cycle; the timer unit (but not the mixer) may be stopped either before or after the mix is discharged; and means may be incorporated to stop the elevator bucket if obstructed as by the shoot of an associated batch weighing plant. The control system comprises a variable speed timer unit including a timer motor 2 driving a shaft carrying cams 3a-3j operating switches 4a-4j; a timer motor starter unit 5 including a continuous cycle starter button 8 closing the citcuit to operating coil 6 operating hold-on contacts 9 and main contacts 10, 11, 12; and a control relay unit 13 including a single cycle start button 15 closing the circuit to operating coil 14 closing hold-on contacts 16, contacts 17 short circuiting the continuous cycle start button 8, and contacts 18 in a circuit across the timer motor stop switches 4d and 4e and across the selector switch 19 for single cycle or continuous operation. A second selector switch 20 on single cycle operation may be closed to short circuit the stop switch 4e and stop the machine after discharging the mix; if left open, the machine continues to mix and does not discharge. A limit switch 21, normally open, is mounted on the associated batch weighing machine and is closed to short circuit the safety stop switch 4f only if the feed shoot 22 of the weighing machine is clear of the path of the elevator mixer bucket. A stop and reset button 25 is provided with which the machine can be stopped, during continuous operation, or the end of the current mixing cycle. A stop button 24 is provided for setting up purposes. There is a controller 23 for remote operation comprising a single cycle start button 15a and a stop position selector switch 20a.