Cutting – With product handling means – By fluid current
Reexamination Certificate
1999-09-10
2001-03-27
Peterson, Kenneth E. (Department: 3724)
Cutting
With product handling means
By fluid current
C083S100000, C083S911000
Reexamination Certificate
active
06205899
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a knife roll for cutting windows out of window envelope blanks.
2. The Prior Art
Such a knife roll is known from U.S. Pat. No. 4,537,588, which shows a knife roll for cutting out the window in window letter envelopes. As the envelope blank is transported with the knife roll, the waste produced by cutting out the window must be retained for a certain time before discharge into a waste hopper. This is accomplished by an axially aligned, single row of suction apertures feeding near the roll surface enclosed by the foil knives. There is another axially extending row of suction apertures in the surface of the roll, which is connected with its own suction* air control channel in the carrier shaft.
However, the row of suction apertures is located in the direction of rotation of the knife roll in front of the knives, and temporarily retains the front edge of the envelope blank on the surface of the roll. Only one single window can be cut out with the cutting roll, and the waste can then be carried along by the knife (or cutting) roll to a discharge point following in the circumferential direction. Furthermore, only one defined size of blanks can be processed, where the spacing of the window from the front edge of the blank is within a comparatively narrow range.
U.S. Pat. No. 3,172,321 discloses a counter roll cooperating with a cutting roll for cutting out windows. The counter roll transports the letter envelope blanks to be provided with windows past the cutting roll. For this purpose, the counter roll has several axially extending rows of suction holes arranged one after the other, with each hole circumferentially spaced from each other. A vacuum can be selectively admitted to the suction holes via a carrier shaft with two axial control channels for suction air. Each channel is communicatively connected via substantially radial channels with an axial distribution channel in the circumferential surface of the carrier shaft. A cup-shaped ring sector having rows of suction holes is supported on the carrier shaft and can be rotated and fixed versus the carrier shaft so that two neighboring rows of holes can be selectively connected with distributing grooves and thus with the suction-air control channels.
However, the two rows of suction holes to which vacuum can be admitted exclusively retain the leading edge of the blank on the counter roll. Adjustments only permit adaptation to different formats (sizes) or spacings between the leading edge of the blank and the window to be cut out. This cutting does not occur near the rows of suction holes, but in a cutting sector following in the circumferential direction. The cutting sector has a particularly hard surface and no suction holes. Therefore, waste cannot be transported in a controlled manner and via vacuum action to a predetermined location for discard.
European Patent No. 0 436 142 shows a knife roller in which foil knifes are chucked on a part of the body of the roll. The roll has a multitude of suction holes arranged in rows on its circumference, for temporarily retaining the material cut out from a letter envelope blank. Suction air control disks arranged on the face side on this part of the roll body enable the periodic feeding of controlled suction air to defined rows of suction holes, via longitudinal boreholes in the axle of the roll. It is thus possible to precisely seize and discharge cut out material with displacement in the circumferential direction of the knife roll. The suction air control disks rotating synchronously with the knife roll are adjustable only relative to the part of the body of the roll, and only have a distribution function in order to admit suction air to selected rows of suction holes. It is a drawback of this reference that the controlled suction air has to travel a long distance, from a suction air control valve through the longitudinal boreholes and the suction air control disks to its site of application on the suction holes on the circumference of the knife roll. This highly impairs chronologically exact seizing and discharging of the pieces of material cut out at high speeds of the roll. Since at most only two suction air control disks can be employed with this knife roll, the number of rows of suction holes to which suction air can be admitted in a controlled way with any one adjustment is limited to two as well, and so is the number of pieces of material transported with one turn (or rotation) of the roll.
Furthermore, an additional suction strip is needed that requires its own support, its own supply of suction air and its own drive. Due to the spatially restricted arrangement of the suction strip and the cutting foil, it is not possible to place window cutouts near the end of the letter envelope blank seized by the suction strip.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to design a knife roll for the manufacture of letter envelopes and also other applications, to be applicable for as many varieties of use as possible.
It is another object of the invention to provide a knife roll that is also capable of safely and reliably discarding more than only one piece of waste per blank to be treated.
It is a further object of the invention to provide a knife roll that produces a window cutout near the leading transport edge of a letter envelope blank.
These and other objects of the invention are accomplished by a rotatable knife roll with at least one foil knife secured on a portion of the body of the roll and having a sharp and endless cutting edge closed within itself to cut out window openings. There are breakthroughs for suction apertures arranged within the cutting edge. There is at least one suction-air control valve arranged on the face side of the roll body. The valve is rotatable relative to this portion of the roll. The suction-air control valve has at least one suction-air-control channel and at least one fresh-air channel.
There are suction apertures for temporarily retaining a letter envelope blank over a suction and transport angle zone &agr;, and for retaining a piece of material cut out by the foil knife across a suction and transport angle zone &bgr;. The suction apertures are arranged in rows to which suction channels are allocated in the part of the roll body. The suction apertures are connected with the suction-air control channel and the fresh-air channel by the suction channels for conducting air. A 3/3-way valve is associated with the suction channel upstream of the suction-air control valve, with an open position for each suction and transport angle zones &agr;, &bgr;, and one common closing position for suction and transport angle zones &agr; and &bgr;.
In the invention, the cutting roll is adjusted in the phase angle relative to the machine producing the letter envelopes so that the transport through the cutting station takes place in the cycle of the machine. Thereafter, through suitable selection and adjustment of the 3/3-way valve, a row of suction holes near the leading edge of the letter envelope blank is activated as the transporting suction row for transporting the blank for a suction and transport angle range &agr;. The rows of suction holes for transporting cut pieces of material via the suction and transport angle range &bgr; are activated in a similar way.
The advantages of the invention are that irrespective of the size, number and position of window cutouts in a letter envelope blank, the correct rows of suction holes can be activated with corresponding selection and adjustment of the 3/3-way valves for transporting the letter envelope blank and the material cutouts via the suction and transport zones &agr; and &bgr;.
The suction-air control valve has a stepped suction-air control channel with a first channel zone for suction and transport angle zone &agr;, which is followed downstream by a first fresh-air channel, and a second channel zone for suction and transport angle zone &bgr;, which is followed downstream by a second fresh-air channel. The first channel
Blumle Martin
Raueiser Reinhard
Choi Stephen
Collard & Roe P.C.
Peterson Kenneth E.
Winkler+Dünnebier Aktiengessellschaft
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