Patent Application
20090019910
The present invention relates to a method of and apparatus for making rod and wire. More particularly this invention concerns such an apparatus that produces finished coils of the rod/wire.
In the drawing:
Wire, which term here is intended also to cover rod, is rolled in at least one finishing frame or stand of a wire mill. The rolled wire then passes through a cooling and/or equalizing stretch downstream of the last finishing stand in the travel direction, where the wire, which is very hot from the rolling operation, cools somewhat and its temperature and crystalline structure stabilize and become uniform. The wire is pulled through the cooling and/or equalizing stretch by means of a cooler drive typically provided at the downstream end of the cooling and/or equalizing stretch. Downstream of the cooler drive a coiler for the wire deposits the wire in turns that may overlap or form a coil on a support, typically a conveyor moving slowly downstream from the coiler. See U.S. Pat. No. 5,463,886 as well as DE 2,437,684 and DE 3,039,101.
The wire to be coiled is produced in a number of finishing stands each normally having two rollers that transversely compress (and thereby longitudinally lengthen) the workpiece as it moves downstream until it has the desired diameter. Since the transverse compression lengthens the wire, it leaves the train of rolling stands or stands at a relatively high travel speed.
Typical prior-art systems are shown in
The wire 1 is pulled through the stretch 4 by a cooler drive 4, typically formed as a pair of rolls or capstan that grip the wire 1, at the speed VD.
Downstream in the direction F from the cooler drive 5 the wire is passed to a coiler 6 that deposits it in turns forming a coil on an output conveyor, table, or the like.
The problem is that the wire travel speed VD is not constant but varies inherently because of the nature of producing wire by rolling, where combined factors of tension and compression are used to produce a product whose size must comply with exact standards. Thus the rolls of the stands 2 are normally driven by meticulously controlled drives that operate with feedback from upstream and downstream sensors so that the finished product is perfect, albeit moving at a somewhat varying speed VD that, as mentioned above, must vary. Even the cooler drive 5 is normally controlled to operate at varying speed to maintain the wire 1 under tension in the stretch 4.
As a result the turns produced by the coiler 6 are not uniform. When the wire 1 is moving too rapidly, the diameters of the turns are too large, and when it is moving too slowly they are too small. Since the speed VD varies during production, for instance as the equipment heats up, it is therefore impossible to produce coils of uniform size.
It is therefore an object of the present invention to provide an improved system for making and coiling wire.
Another object is the provision of such an improved system for making and coiling wire that overcomes the above-given disadvantages, in particular that produces coils having turns of uniform controlled size.
A method of making wire has according to the invention the steps of rolling out a wire in a mill having a finishing stand from which the wire exits at a predetermined and varying travel speed VD, pulling the wire through a cooling/equalizing stretch downstream in a travel direction from the finishing stand by means of a cooler drive at a downstream end of the finishing stretch such that the wire exits the cooler drive substantially at the travel speed VD, passing the wire through a looping stretch downstream of the cooler drive to a looper drive, operating the looper drive at such a speed that the wire forms a loop between the cooler drive and the looper drive and exits the looper drive at a looper speed VT normally different from the travel speed VD, and forming the wire into turns and depositing the turns as a coil downstream of the looper drive.
According to the invention the looper drive can be regulated such that the loop height is within a predetermined value range between an upper limit and a lower limit.
Preferably, the drive speed of the coiler is also controlled with or without feedback according to the speed of the looper drive.
The wire in the cooling and/or equalizing stretch between the last finishing stand, and the cooler drive is preferably held at a predetermined tension. Furthermore, a further drive is arranged within the cooling and/or equalizing stretch to maintain tension in the wire.
The wire mill according to the invention has a looper drive is arranged in the travel direction downstream of the cooler drive and upstream of the coiler. This looper drive can be driven such that the wire forms a loop having a loop height measured relative to a straight target line between the two drives.
For regulating the size of the loop, a sensor is preferably provided for detecting the height of the loop, that is a vertical position of the lowest portion of the loop. Furthermore, a controller is advantageously provided that is connected to the sensor so as to influence a drive motor of the looper drive.
The controller may also influence a drive motor of the coiler to synchronize the working speed of the looper and the coiler.
The proposal according to the invention ensures that using relatively simple means, the wire can be deposited by means of the coiler in turns of constant diameter. Any variations in wire speed, which are present downstream of the finishing stand, can be adjusted out in a simple manner.
The rolling process is thereby decoupled from the coiling.
Wire coils having fewer problems with deviations of the diameters of the turns, and less system downtime are achieved in an advantageous manner.
As seen in
The critical factor is that according to the invention a looper drive 7 is arranged in the travel direction F downstream of the cooler drive 5, and upstream of the coiler 6. The two drives 5 and 7 are spaced from each other. The looper drive 7 is selectively operated by a controller 11 so that the wire 1 forms a loop 8 between the two drives 5 and 7. As seen in
The looper drive 7 conveys the wire 1 at a speed VT, which is kept largely constant, and due to which a constant turn diameter of the wire 1 is formed when it is deposited in turns by the coiler 6. The looper drive 7 is operated at the mainly constant speed VT, and the speed VT, of the coiler 6 is coupled to the drive speed of the looper drive 7, so that the coiler 6 and looper drive 7 operate synchronously.
Any variations of the speed VD can be balanced in this manner growth or shrinkage of the loop 8, and the feed of the wire 1 into the coiler 8 occurs by means of the looper drive 7 at a constant speed VT. This leads to an optimum layout, since the winding diameter is constant.
In this regard, details are illustrated in
The actual or current value of the loop height H is determined by means of a sensor 10, which may be, for example, a photo sensor, which is capable of measuring the maximum displacement of the wire 1 from the target line 9. The value for the loop height H determined by the sensor 10 is fed to the control means or controller 11.
The controller 11 operates a drive motor 12 of the looper drive 7 such that the loop height H stays within the permissible range, that is between Hmax and Hmin. If the value for the loop height becomes too high, the drive motor 12 is made to rotate faster, if the value becomes too small, the drive motor 12 becomes slower. The loop height H is therefore maintained at a desired value in the closed loop.
As schematically indicated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 102007032987.5 | Jul 2007 | DE | national |
