Patent GB-1114001-A (GB)
Title: Improvements relating to the speed control of coil winders
Inventor: DAVIES RICHARD EDWARD
IPC: B65H26/08
Filed: 1965-03-23
Abstract: 1, 114, 001. Measuring speed electrically. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. March 16, 1966 [March 23, 1965], No. 12254/65. Heading G1N. [Also in Division B3] The linear speed of strip material being drawn from (or being wound on to) a mandrel 1, Fig. 1, varies the frequency f 1  of the output of a pulse generator 6, and the speed of rotation of the mandrel 1 varies the frequency f of a second pulse generator 5, the frequency f being changed by a constant k in a frequency changer 7, the output fa of which is compared with f 1  in a unit 8 which gives an output signal when fa becomes greater than f 1 . The unit 8 thus gives an indication of when a predetermined coil thickness remains on the mandrel, since for a constant linear strip speed, the angular speed of the mandrel 1 increases, and the frequency fa increases, as the diameter of the coil reduces. The frequency changer (9, Fig. 2, not shown) may provide a plurality of output signals at different terminals of a uniselector (10), each output signal being produced by changing the input frequency (f ) by a different constant (k 1 , k 2 , k 3  &c.). ). When the unit 8, Fig.1, operates, upon fa exceeding f 1 , its output energizes a coil (11) which indexes the uniselector arm (10) to the next position, at which a higher value k 2  of the constant reduces the value of fa; fa again increases with reducing coil diameter at 1 until it once more exceeds f 1  and causes the unit 8 to index the uniselector arm (10) to a further position. The position of the arm (10) thus represents the thickness of the coil remaining on the mandrel, 1. The uniselector arm (10) is mechanically linked to a wiper (12) which applies a voltage V2 via progressively increasing resistors (R2A-R2N) to a comparator (A) in the form of a current I 2 , and when this equals a current I 1  representing linear strip speed a trigger circuit 14 operates a brake. Thus the lower the linear strip speed the later the braking. The voltage V 2  is adjusted for strip thickness. In an alternative, a further potentiometer (17, Fig. 3, not shown) the wiper of which is set to represent the inverse of the square root of the gauge thickness (T) of the strip material, energizes a stepped resistor (16) carrying the wiper (12). Thus the signal from the wiper (12) is dependent upon both the strip thickness (T) and the amount of strip left on the mandrel, and is supplied to an integrator (18) which produces a current (i 2 ). To this is added a current (i 1 ) from a potentiometer (19) which is inversely proportional to strip thickness (T). The sum of these currents (i 1 ) and (i 2 ) is shown to be proportional to the length of strip (S) remaining on the mandrel. A tachogenerator (TG) produces a signal (i 2 ) proportional to the speed, u, of the strip and this is modified in an integrator (20) and resistor (21) to give a signal proportional to u2/2f where f is the deceleration which it is possible to impose upon the system. In order to bring the mandrel to rest before the end of the strip leaves the mandrel, the signals (i 1  + i 2 ) and (i 3 ) are compared in a difference amplifier (15), which initiates deceleration when the two signals are equal so as to satisfy   the equation S = u<SP>2</SP>/2f.