Slitting Machine

A slitting machine having at least two knife holders, with a respective knife rotatably mounted on each knife holder. Individually activatable electromagnetic sensors are disposed on the knife holders, and a single magnetostrictive rod extends through a portion of all of the electromagnetic sensors. A unit processes interrogations by the rod of activated ones of the electromagnetic sensors for indicating the position of at least one of the knife holders relative to the rod.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring now to the drawings in detail, the slitting machine of the present application is designated generally by the reference numeral20inFIG. 1, and includes a plurality of knife or blade holders22, only one of which is visible inFIG. 1, the angle of viewing of which is parallel to the direction of displacement of the knife holders22. Associated with each knife holder22is a blade or knife23that is rotatably mounted on the knife holder, an electromagnetic sensor24that is fixedly mounted on the knife holder, a single magnetostrictive rod25, and means27, such as a computer, for processing an interrogation by the magnetostrictive rod25of the electromagnetic sensor24.

The electromagnetic sensors24have a C or U shaped portion (seeFIG. 2) through which the single magnetostrictive rod25extends. The rod25is stationarily mounted, so that as the knife holders22are displaced, the electromagnetic sensors24, which due to their fixed mounting on the knife holders22travel along with it, are correspondingly displaced along the length of the magnetorestrictive rod25, which extends in a direction parallel to the direction of displacement of the knife holders22. When one of the electromagnetic sensors24is activated, in other words when power is supplied to it, the electromagnetic sensor creates a magnetic field. This magnetic field can be sensed by the magnetostrictive rod25, and the signal generated is conveyed from the magnetostrictive rod25to the computer or other means27for processing such an interrogation of the activated electromagnetic sensor24. The means27can then provide feedback regarding, i.e. can indicate, the position of the electromagnetic sensor24, and hence of the blade holder22, relative to the magnetostrictive rod25. In one exemplary embodiment, the sensor24, made from a cold rolled steel blank, is wound with 28 ga mag wire (six passes). The blank has a thickness of, for example, 0.08 inches.

Thus, as the knife holders22, along with their knives23, are appropriately positioned for slitting by being displaced on a rail or cross beam, the electromagnetic sensors24are moved along with the knife holders22on which they are fixedly mounted. By activating a number of electromagnetic sensors24in a staggered manner, not only can the position of the knife holders22relative to the magnetostrictive rod25be detected and indicated, but also the position of the knife holders22relative to one another can be indicated.

FIG. 3schematically indicates how pursuant to the slitting machine of the present invention, the number of knife holders22, and hence the number of associated electromagnetic sensors24, that can be provided using only a single magnorestrictive rod25for the electromagnetic sensors, is limited only by the relatively narrow thickness or width of the knife holders22, and of course the length of the rod25. This for the first time possible, immediately adjacent to one another arrangement of the knife holders22is due to the fact that with the slitting machine of the present application, the electromagnetic sensors24can be turned on and off in a staggered manner. The minimal spacing between adjacent knife holders22that can be achieved with the present invention provides for a far greater accuracy in determining the exact position of a given knife23. For example, whereas with heretofore known devices, the permanent magnets provided on a single magnetostrictive rod had to be spaced at least two to two and a half inches apart, with the slitting machine of the present application the electromagnetic sensors24can be spaced one half inch or even less apart on a single magnetostrictive rod25.