Patent GB-1529790-A (GB)
Title: Spoolers
IPC: B65H54/38
Filed: 1975-11-20
Abstract: 1529790 Tension control, preventing excess or defficiency of windings at spool ends BABCOCK WIRE EQUIPMENT Ltd 20 Nov 1975 [21 Aug 1974 (2)] 36779/74 and 36780/74 Heading D1J The invention relates to apparatus for traversing wire onto a flanged spool via a wire tension controller providing a measuring signal to regulate the speed of spool rotation, the apparatus having means for varying the length of the traverse stroke in response to changes in the length of the wire in the wire tension controller whilst the wire being wound is in a period adjacent to a moment of traverse reversal, the change of traverse length being such as to ensure that there is no excess or deficit in spool size adjacent the flanges of the spool. According to the invention the apparatus includes means for diverting the measuring signal from the speed control means to the traverse control means when the traverse means is approaching a reversal point so as to keep the spool speed constant during traverse reversal periods; the periods at which the switching means acts on the traverse control being such that each period commences always when the reciprocating movement has a pre-determined fixed distance yet to go before the reversal point is reached and terminates either when the reciprocating movement reaches the reversal point or when the reciprocating movement reaches the same position during the return from the reversal point; the reversal point adjusting means being arranged to adjust the reversal point by an amount proportional to the final valve of the measuring signal at the end of such period. Spool Speed. In Fig. 1 the wire 1 passes around dancer rollers 22a to 22c acting as part of a tension control 3 and thence over a traversing mechanism 4 to the spool 6 driven by a variable speed means 8. If the tension in the wire 1 increases a float arm 14 of the tension control 3 rises and rocks shaft 15 in a direction causing a potentiometer transducer 33 to adjust spool speed controlling means 9 coupled to the motor 8 such that the take up speed of the spool is reduced. Similarly if the tension in the wire 1 reduces the arm 14 rocks in the opposite direction to cause the spool speed to be increased. The arm 14 is biassed against the tension in the wire 1 by avariable torque drive 13 actuated by a motor 11. The variable torque drive 13 may be of the magnetic type. Traverse Control 1st Embodiment. In this embodiment, Fig. 3, the wire traversing means 4 is reciprocated by an endless belt 47 driven by an electric stepping motor 49, there being a proximity switch 50 that is responsive to the passage of a tongue 51 of a sliding carriage 10 that is coupled to the belt 47 and carries the wire traversing means 4. When the carriage 10 moves from left to right, say, and the tongue 51 passes the proximity switch 50, a counter (55), Fig. 4 (not shown), commences to count pulses from a pulse generator (52) coupled to the stepping motor 49 and this counts the number of steps by which the motor is rotated. A comparator (61) compares the increasing count in counter (55) with a predetermined count in a right-hand register (62R) and when they agree a signal is passed to a reversing signal control (67) to a direction control that reverses the direction of the motor 49. The counter (55) then resets to zero, the carriage 10 commences to move from right to left, and when the tongue 51 passes the proximity switch 50 the above sequence is repeated except that this time the count accumulated in the counter (55) is compared with a pre-determined count in a left-hand register (62L). If the left-hand register (62L) is set too low then the spool diameter at the left-hand flange does not build up at the same rate as the main part of the spool. As a result the tension control means 3 will experience a reduction of tension in the wire when the traversing means 4 is at the left-hand end of its traverse and this reduction in tension causes the arm 14, and consequently the potentiometer 33, to be moved to a setting in which a signal is sent via a line 35a, Fig. 1, to means increasing the count on the lefthand register (62L) by an amount that is proportional to the displacement of the arm 14 from its normal position. This increases the traverse stroke to the left of subsequent traverse strokes. Similarly if the build up of the spool near the left-hand flange is too great then the wire 1 when it reaches said left-hand end experiences a sudden increase in tension and this causes the floating arm 14 to rise and so rotate the potentiometer 33 to setting in which a signal is sent via line 35a to means decreasing the count on the left-hand register (62L) by an amount that is proportional to the displacement of the arm 14 from its normal position. Excessive build up or reduction of the spool near the left-hand is thus prevented. Similar considerations apply when the traverse means 4 is near the right-hand end of the spool. Traverse Control 2nd Embodiment In this embodiment, Fig. 5, the wire traversing means 104 is again reciprocated by an endless belt 105 driven by a reversible motor 106. The traverse control comprises limit switches such that when the traversing means 104 engages switch 110L, in a switch housing 107L, the motor 106 is reversed in a direction to move the traverse means 104 to the right. Similarly when the traversing means 104 engages switch 110R, in a switch housing 107R the motor 106 is reversed to move the traversing means 104 to the left. Before the traversing means 104 engages switch 110L or 110R it engages switch 112L or 112R that then remain in operation until the means 104 has been reversed in direction and is leaving the switch 112L or 112R. While either switch 112L or 112R is in operation the speed of the spool is held constant. If there is an excess or a deficit in the winding diameter near a spool end the resulting difference in spool diameter will cause the tension responsive arm 14 to be deflected such that a signal from the potentiometer 33 via line 15a will cause associated circuitry to rotate a screw thread 108L, on which the switch housing 107L is mounted, such as to move the housing 107L in a direction as to cause the traverse stroke to decrease or increase in the region of the left-hand spool flange according to whether there is an excess or deficit of winding near the left-hand spool flange. Delay means ensure that the housing 107L is not moved until the traverse means 104 has moved away from the left-hand spool flange and is clear of the switch housing 107L. Similar considerations apply at the righthand spool flange and for this purpose the switch housing 107R is mounted on a screw thread 108R that can be actuated in a similar manner to the screw thread 108L when there is an excess or deficit of winding near the right-hand spool.