Loop follower straightener control in a press installation
AssigneeThe Minster Machine Company
InventorsGary T. Grew, Ronald F. Fortman
Life of this patent
Estimating the term…
Abstract
The present invention relates to a loop follower control system for use in a mechanical press or other machine installation for the purpose of controlling the amount of stock loop between the straightener and the press. An idler arm engages the loop of stock between the straightener and the press, and is connected to an potentiometer to develop a current or voltage proportional to the deviation of the idler arm from the desired position. The control current or voltage developed controls an eddy current drive to increase or decrease the speed of the rollers and straightener depending on the amount of error indicated by the control signal.
Claims12
In a press installation comprising a coil of strip stock, a press, press feed means for feeding strip stock into the press, and a motor driven straightener means positioned between the coil and feed means for feeding the stock to the press feed means and removing the curvature from the stock, the stock being slack between the straightener means and press feed so as to form a loop, apparatus for controlling the speed of the straightener means comprising:
- a control arm mechanism engaging the loop of stock and adapted for moving in accordance with the size of the loop,
- potentiometer means connected to said control arm mechanism for producing on an output an electrical feedback signal the magnitude of which varies proportionally with the movement of the control arm mechanism,
- a variable speed motor drive means for driving said straightener means and having a control input, said motor drive means including means for varying the speed of the straightener means proportionally in response to a control signal on said control input,
- a manually settable loop size control means for generating a reference signal having a variable magnitude and including a digital display means for displaying a multiple digit number corresponding to the magnitude of the reference signal,
- feedback control means having a first input to which the feedback signal is connected, a second input to which the reference signal is connected, and an output connected to the motor drive means control input, said control means generating a control signal on its output which is proportional to the deviation of the feedback signal from the reference signal,
- a long loop limit switch means connected to said straightener means and positioned to be actuated by said control arm mechanism to stop said straightener means when the loop reaches a predetermined size, and
- means for adjusting the spatial relationship between the control arm mechanism and limit switch whereby the point in the path of movement of the control arm mechanism whereat the limit switch is actuated can be varied,
- said feedback control means including means for continuing to cause said drive means to drive said straightener means, even after the feed means is stopped, until said limit switch is actuated, to thereby cause said loop to obtain the desired size prior to restarting of the press.
Dependencies are inferred from the claim text.