PLUNGE SLITTING WITH ENHANCED SCRAP THREADING CAPABILITY USING MULTIPLE SIZE KNIVES

Abstract

A slitting machine for threading scrap material has first and second arbors. A first set of rotary knives are disposed on each of the first and second arbors having a first diameter. A second set of rotary knives are disposed on each of the first and second arbors having a second diameter. The second diameter is smaller than the first diameter. As the arbor gap is closed, the first set of rotary knives cut edge trim and when the arbor gap is further closed, the second set of rotary knives cut mutts from the strip.

Claims

1. A slitting machine for threading scrap material comprising: first and second arbors; a first set of rotary knives disposed on each of said first and second arbors, said first set of rotary knives having a first diameter; a second set of rotary knives disposed on each of said first and second arbors, said second set of rotary knives having a second diameter; wherein said second diameter is smaller than said first diameter.

2. The slitting machine of claim 1, whereas spacers are positioned between each of said rotary knives.

3. The slitting machines of claim 2, wherein sleeves are placed over said spacers.

4. The slitting machines of claim 1, wherein said arbors are adjustable to change a gap between said first and second arbors.

5. The slitting machine of claim 4, wherein said gap between said first and second arbors is closed while an associated strip travels through the slitting machine so that a gap between said first set of rotary knives is small enough so that said first set of rotary knives cut an edge trim from said strip.

6. The slitting machine of claim 5, wherein a gap between said second set of rotary knives is too large to cut said strip.

7. The slitting machine of claim 4, wherein said gap between said first and second arbors is closed while an associated strip travels through the slitting machine so that a gap between said second set of rotary knives is small enough so that said second set of rotary knives cut mults from said strip.

8. The slitting machine of claim 7, wherein a gap between said first set of rotary knives is small enough so that said first set of rotary knives cut an edge trim from said strip.

9. The slitting machine of claim 1, wherein a scrap chopper and chute are positioned at an end of said slitting machine.

10. A method for threading scrap material through a slitting machine comprising: providing first and second arbors; providing a first set of rotary knives having a first diameter disposed on each of said first and second arbors; providing a second set of rotary knives having a second diameter disposed on each of said first and second arbors; wherein said second diameter is smaller than said first diameter; closing a gap between said first and second arbors to enable said first set of rotary knives to cut edge trim from said strip.

11. The method of claim 10, wherein said first and second arbors are adjustable to change a gap between said first and second arbors.

12. The method of claim 11, wherein said gap between said first and second arbors is further closed while the associated strip travels through the slitting machine so that a gap between said second set of rotary knives is small enough so that said second set of rotary knives cut a mult from said strip.

13. The method of claim 10, wherein a scrap chopper and chute are positioned at an end of said slitting machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a perspective view of an existing slitter and scrap chopper assembly;

[0030] FIG. 2 is a perspective view of a slitter with multiple diameter knives and scrap chopper assembly in accordance with a preferred embodiment of the disclosure;

[0031] FIG. 3 is a top plan view of multiple diameter knives in accordance with a preferred embodiment of the disclosure;

[0032] FIG. 4 is a side elevational view of the knives of FIG. 3;

[0033] FIG. 5 is a front elevational view of the knives of FIG. 3;

[0034] FIG. 5A is an enlarged elevational view taken along detail B illustrating arbors plunged for edge trim only;

[0035] FIG. 5B is an enlarged elevational view taken along detail B illustrating arbors plunged to cut all mults.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0036] The present disclosure relates to plunge slitting. More particularly, it relates to plunge slitting with improved scrap threading capability by using multiple size diameter knives.

[0037] The preferred embodiment of the disclosure in shown is FIGS. 2-5B. Scrap choppers B and chutes C can be positioned immediately after slitter arbors 22, 24. FIG. 2 shows that lower slitter arbor 24 can be adjustable upwardly and downwardly to adjust the arbor gap G. Referring to FIG. 2, a slitter A and scrap chopper arrangement B and chute C are shown. The slitter and scrap chopper are shown separately for clarity. The scrap chopper B is shown to illustrate the problem of how to get the scrap trim into the chopper where the first two feet of strip, or more or less, is not cut through (i.e., the uncut zone 4C). This problem exists regardless whether a scrap chopper or scrap winder is used.

[0038] Stripper rubber sleeves 26 are positioned on spacers 28 between knives 30, 32. All the inwardly positioned knives 30 on the parallel slitter arbors 22, 24, except the outer pairs 32, are of the same diameter D1. The outer pairs of knives 32; i.e., one pair at each of the two outside edges, are at a diameter D2 which is larger diameter than D1. There are preferably four knives 32 of diameter D2 while there may be multiple pairs of knives 30 of diameter D1 dependent on the desired results. For a given gap between the upper and lower arbors 22, 24, the gap between the larger diameter knives 32 will be tighter than the gap between the smaller diameter knives 30.

[0039] In this manner, during plunge slitting, when the gap between the knives 30 is too large to cut strip 34, the gap at the knives 32 is small enough to cut through the strip. There can be multiple pairs of knives 30 dependent upon the number of mults formed on the strip. Thus the scrap (trim) is cut all the way through and threads itself into the scrap chutes. This overcomes the shortcomings of existing practice.

[0040] As the arbor gap G closes it is important for the strip 34 to be advancing otherwise the separating force between the arbors would get quite large and possibly overload the slitter arbor bearings.

[0041] In accordance with a preferred embodiment of the disclosure, strip material 34 is fed into the line and the slitter arbor gap G is preset too large to make the cut (i.e., during initial threading through the slitter). As the strip advances to the slitter, the slitter arbors are closed further at a closure speed that is appropriate to the strip advance speed.

[0042] If only an edge trim of the strip 34 is desired, as the arbors 22, 24 are closed or unplunged, the outer knives 32 cut or trim the outward edge of the strip, while the inner portions remains uncut due to the inner smaller diameter knives 30 not contacting the strip 24.

[0043] If the arbors are further closed or plunged, then the mults are cut by the inner knives 30, while the edge trim is cut the outer knives 32. When strip 34 has advanced far enough and slitter arbors are at their final cutting gap the strip will be cut all the way through including the mults and edge trim. Each edge has a trim width that will automatically thread itself into the scrap chutes and on into the scrap choppers or down to scrap winders.

[0044] Referring now to FIGS. 3, 4, 5, a slitter with multiple diameter knives in accordance with the preferred embodiment of the disclosure is shown in more detail.

[0045] Outer knives 32 are shown to be of diameter D1 which is larger than the diameter D2 of the inner knives 30. Spacers 28 with sleeves 26 are positioned between the knives on arbors 22, 24 (FIG. 2).

[0046] Referring to FIG. 5A, as the arbor gap G is closed, the outer knives 32 begins to form a cut line CL forming an edge trim while the inner knives 30 have a gap or knife clearance KC with the strip. The inner knives 30 do not cut the strip. Thus, only the edge trim is cut or slit from the strip by knives 32.

[0047] Referring to FIG. 5B, the arbor gap G is further closed, allowing both the outer knives 32 to form a cut line CL and the inner knives 30 to form a cut line CL. In this arrangement, the arbors are plunged to cut all of the mutts with knives 30 as well as the edge trim with knives.

[0048] The disclosure has been described with reference to a preferred embodiment. Obviously, modifications and alterations may occur to others while reading and understanding the preceding detailed description. It is intended that the disclosure includes all such modifications and alterations insofar as they come within the scope of the preceding description and appended claims.