Cut-off Device

Abstract

A rotary shear or cut-off device for web fed materials such as paper napkin stock that includes a novel adjusting means, the device being capable of operating at high speeds without difficulties, and wherein all four edges of the knife, such as the anvil knife, can be used, and wherein chamfered edges are utilized on the anvil knife and fly knife.

Description

The present invention relates to a cut-off device for web fed materials such as paper napkin stock.

An object of the present invention is to provide a rotary shear or cut-off device for web fed material such as paper napkin stock wherein the device or mechanism is relatively simple in construction and easy to adjust, and wherein the device is constructed so that it can run or operate at high speeds without any ill effects, and wherein in the system of the present invention the percent of over speed of the fly knife roll is not critical and this is advantageous because it permits the roll diameter of the fly knife roll to be increased in the event deflection becomes a problem due to a short cut off length.

Another object of the present invention is to provide a cut-off device wherein all four edges of the anvil knife can be used, and wherein there is provided a novel gear arrangement for the cut-off system or rotary shear of the present invention.

Still another object is to provide a cut-off system that is an improvement over such prior systems or devices as those shown in prior U.S. Pat. Nos. 2,478,240 and 3,247,746.

Another object is to provide a cut-off system that is adapted to minimize errors productive of wasted labor and material in the formation thereof, and further objects and advantages are to provide improved elements and arrangements thereof in a device of the character described that is relatively economical to produce, durable in form, and conducive to the most economical use of materials and uniformity of members formed therefrom.

Further objects and advantages will become apparent in the subsequent description in the specification.

In the drawings:

FIG. 1 is an end view of the gearing device of the present invention.

FIG. 2 is a sectional view taken on the line 2--2 of FIG. 1.

FIG. 3 is a fragmentary sectional view taken through the fly knife roll and anvil knife roll at the beginning of a cut.

FIG. 4 is a view generally similar to FIG. 3, but with the parts rotated towards the end of a cut.

FIG. 5 is an exploded perspective view of the fly roll and its associated parts.

FIG. 6 is a side view of the fly knife.

FIG. 7 is an exploded perspective view of the anvil knife and its clamping means.

FIG. 8 is an end view of the anvil knife.

Referring in detail to the drawings, the numeral 20 indicates the rotary shear or cut-off device of the present invention, and the rotary shear is adapted to be used for cutting paper napkin stock and the like which is held against the surface of the vacuum roll 21 by a vacuum means 30 or the like. The vacuum means is actually a series of small holes (one-eighth inch to five thirty-seconds inch) through clean out plate 30A.

As shown in the drawings, such as in FIG. 3, the vacuum roll 21 holds an anvil knife 22. The numeral 23 indicates a single repeat roll that carries a fly knife 24, and the numeral 25 indicates a fly knife or blade holder. As shown in the drawings, a wedging or angle block 26 is provided adjacent the holder 25 and the adjustment of these parts determines the angle of the fly knife 24 with the center line of the repeat roll 23. The fly knife 24 is adapted to be adjusted by fine threaded set screws or securing elements 43 and 44. The anvil blade 22 has chamfered edges 31 thereon, FIG. 8, and this chamfer 31 may have a suitable configuration such as 45.degree. .times. 0.042 inches, and runs along the entire length on all four sides.

The fly knife blade 24 has a chamfered corner 29, FIGS. 5 and 6, to help it get under the anvil blade 22. Four corners 31 of the anvil knife 22 are adapted to be chamfered across the entire cutting edge on all four sides for use on all four sides of the knife or device.

As shown in the drawings, such as in FIG. 2, the vacuum roll 21 and fly knife roll 23 are mounted on shafts 19 and 18, respectively, that rotate in bearings 32, and the bearings 32 may be supported by a suitable frame or supporting structure 33 of a desired configuration or formation.

As shown in FIG. 2, there is provided a split gear 36 that consists of gear members 34 and 35 that are mounted on the hub 37 for driving the fly knife roll gear 38 that is fixed to the roll journal by hub 39 through the medium of bolts 40. The bolts 40 may extend through slots 17.

Pins 41 are pressed into the gear 38 and extend into the hub 39 through over-sized holes or openings. It will be noted that by loosening the bolts 40 and adjusting the set screws 42 on either side of the pins 41, a fine tune of the cutting edges can be obtained before the fly knife blade set screws 43 and 44 are utilized.

As shown in the drawings, the one half gear 35 is fixed to the hub 37 by bolts 45, and the gear 35 does the driving of the fly knife roll gear 38. The other half 34 of the vacuum roll gear is adjusted in a direction opposite to its rotation by loosening the bolts 46 and adjusting the set screws 47 on either side of pin 48 so as to remove all of the backlash between these gears, as later described in this application.

It will be noted that the anvil blade 22 is held in place by block 49 and clamped against the face of block 50 by slight loosening of the bolts 51 in block 49, and tightening of the bolts 52 in the wedging block 53 which slides the block 53 sideways down its tapered seat 54.

From the foregoing, it will be seen that there has been provided a rotary shear or cut-off device which is especially suitable for cutting paper napkin stock and the like, and in use with the parts arranged as shown in the drawings, power can be supplied from any suitable source of supply so as to rotate the pair of rolls 21 and 23 towards each other, as indicated by the arrows 55 and 56 in FIGS. 3 and 4. As is well known, the paper napkin stock or other stock is held against the surface of the roll 21 in any suitable manner, as for example, by means of a vacuum arrangement 30 which forms no part of the present invention.

The present invention thus consists of the vacuum roll 21 that holds the anvil knife 22, and there is further provided the single repeat roll 23 which carries the fly knife 24. The fly knife 24 is held in place by means of a fly knife blade holder 25 that is maintained at its proper location by means of the wedging or angle block 26, and the position of these parts determines the angle of the fly knife 24 relative to the center line of the roll 23. The fly knife roll 23 is generally a single repeat roll, while the vacuum roll 21 may be used in repeats of two, three and four, as shown in dotted lines in FIG. 1, and no apparent ill effects are noticeable. The surface speed of the tip of the fly knife blade 24 may be used at from approximately 31% to 75% higher than the cutting edge of the anvil blade 22 with no shortcomings as to speed limitations.

The larger percent of over speed can be used on small repeat sizes to get a larger fly knife roll body to eliminate roll deflection problems and the like.

With the present invention, the fly knife blade 24 is not being bowed or curved as is the case in prior U.S. Pat. No. 3,247,746. The fly knife blade 24 is adjusted by the fine threaded set screws 43 and 44 in generally a straight line until it acts with the anvil knife 22 and cuts the web. One of the main aspects or features of the present invention is the 45.degree. .times. 0.042 inches chamfer 31 of the anvil blade 22, although it is to be understood that other configurations of the chamfer can be used on the anvil blade. Heretofore, before this chamfer 31 was added or utilized, a very poor fly knife blade life resulted. In addition, fly knife blade 24 has a chamfered corner 29 on the leading edge to help it get under the anvil knife 22. This blade can be chamfered on all four corners for use on all four cutting edges. Further, the anvil knife 22 is also chamfered across the entire cutting edge on all four corners for use on all four corners. The anvil knife 22 may be made of a high speed tool steel of 66-68 Rockwell "C", and the fly knife may be made from either a high speed steel or a Swedish high carbon spring steel. While both work equally well, the use of spring steel provides certain advantages from a point of view of cost.

It is to be noted that the vacuum roll 21 and the fly knife roll 23 rotates in bearings such as bearings 32. There is provided a split gear 36 that embodies or includes members 34 and 35 that are mounted on the hub 37, and this split gear arrangement drives the fly knife roll gear 38 which is fixed to the roll journal by hub 39 through bolts 40. Pins 41 are adapted to be pressed into the gear 38 and extend into the hub 39 through oversized holes. By loosening the bolts 40 and adjusting the set screws 42 on either side of the pin 41, a fine tune or adjustment of the cutting edges can be accomplished or obtained before the fly knife blade set screws 43 and 44 are utilized.

In addition, the one-half gear 35 is fixed to the hub 37 by bolts 45, and the gear 35 does the driving of the fly knife roll gear 38. The other half of the vacuum roll gear 34 is adjusted in a direction opposite to its rotation by loosening bolts 46 and adjusting the set screws 47 on either side of the pin 48, in order to remove all of the backlash between these gears.

It will be noted that the anvil blade 22 is held in place by the block 49 and is clamped against the face of the block 50 by slight loosening of the bolts 51 in the block 49 and tightening of the bolts 52 in the wedge block 53 which slides the block 53 sideways down its tapered seat 54. Bolts or screws 58 serve to connect the block 50 to the vacuum roll 21, as shown in FIGS. 3 and 4.

It is to be understood that the parts can be made of any suitable material and in different shapes and sizes, as desired or required.

The present invention will permit high speed operations to be carried out, and there is provided a rugged construction, and not only does the web cut-off device of the present invention give extremely long life but is easily adjustable. Maintenance is minimized, and the machine is engineered for high speed operation, and in addition, versatility is assured.

With further reference to the present invention as compared to prior patents, such as prior U.S. Pat. No. 3,247,746, it is to be noted that the present invention does not include a slot equipped plug in a slot enlargement, nor does it include holder means mounted in plug slots. Also the present invention is different from or an improvement over the construction of prior U.S. Pat. No. 3,247,746, inasmuch as it does not include the end plugs, the plug and screw arrangement, and the helix formation.

It will be noted that in the present invention there is a blade 24 with four cutting edges held in a channel-shaped holder, spaced at an angle relative to the axis of the small roll by the wedging block 26, and final adjustment of this blade 24 is accomplished by using the set screws 43 and 44. The matching knife or anvil blade 22 also has four cutting edges 31 and has a 45.degree. chamfer on each edge, which makes the blade easier to adjust. Thus, the present invention is relatively simple in construction and is very easy to adjust, and it is capable of operating at high speeds without any ill effects.

A further advantage of the present invention is that the percent of over speed of the fly knife roll 23 is not critical. This is advantageous, because it permits the roll diameter of the fly knife roll 23 to be increased should deflection be a problem due to a short cut off length, and the like.

The present invention has the advantage in that all four edges of the anvil knife 22 can be used. Due to the thickness and method of holding, this knife very seldom breaks, but it becomes dull after being used for a period of time.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Claims

I claim:

1. In a web cut-off device for cutting paper napkin stock and the like, a vacuum roll and a fly knife roll, an anvil knife, and a fly knife mounted in said vacuum roll and fly knife roll, respectively, a holder for said fly knife, a wedge block positioned adjacent said holder, adjustable set screws operatively connected to said fly knife roll and engaging said holder and wedge block, said anvil knife having chamfered edges that run along its entire length on all four sides thereof, said fly knife having chamfered corners thereon, and holding means for the anvil knife.

2. The structure as defined in claim 1, wherein said last-named holding means comprises a block affixed to said vacuum roll, and a wedging block and clamping block for said anvil knife.

3. The structure as defined in claim 1, and further including gear means.

4. The structure as defined in claim 1, and further including gear means that comprises split gear members, hubs associated with said gear members, and securing elements and pins operatively associated with said gear means.

5. The structure as defined in claim 1, wherein the fly knife has a chamfered corner on the leading edge to help it get under the anvil knife.

6. The structure as defined in claim 1, wherein the fly knife is adapted to be chamfered on all four corners for use on all four cutting edges, and wherein the anvil knife is chamfered across the entire cutting edge on all four corners for use on all four corners.

7. The structure as defined in claim 1, and further including gear means that comprises split gear members, one of said split gear members being adjustable in a direction opposite to its rotation by loosening securing elements and adjusting said screws in order to remove all backlash between these gears.

8. The structure as defined in claim 1, wherein the holding means for the anvil knife includes a block affixed to the vacuum roll, and the wedging block thereon.

9. A new article of manufacture, a web cut-off device for cutting paper napkin stock and the like, comprising a vacuum roll and a fly knife roll, an anvil knife mounted in said vacuum roll, a fly knife mounted in said fly knife roll, a holder for said fly knife, a wedge block positioned adjacent said holder, adjustable set screws operatively connected to said fly knife roll and engaging said holder and wedge block, said knives having chamfered edges and corners, holding means for the anvil knife, said last-named holding means comprising blocks, one of which has a tapered seat, said web cut-off device further including gear means that embodies split gear members, securing elements and pins operatively connected to said gear means, said fly knife having a chamfered corner on the leading edge to help it get under the anvil knife, the anvil knife being chamfered across the entire cutting edge on all four corners for use on all four corners.