Cutting – With means to monitor and control operation – Including means to compensate tool speed for work-feed...
Reexamination Certificate
1998-11-23
2001-03-27
Rachuba, M. (Department: 3724)
Cutting
With means to monitor and control operation
Including means to compensate tool speed for work-feed...
C083S286000, C083S287000, C083S289000, C083S293000, C083S295000, C083S343000
Reexamination Certificate
active
06205898
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The invention relates to cutoff devices for strip material and, in particular, to a rotary cutoff device, which is adapted to permit the sheet web material to pass through the device, while the device is stationary and the shear device being operable intermittently to cut the web material at predetermined spaced locations.
BACKGROUND ART
The cutting of moving strip material has been carried out in a variety of ways. In one relatively primitive method, the moving strip was temporarily stopped at a point just before a shear blade, and the shear blade was operated. Upstream of the shear blade the strip continued to move and formed a loop. Once the shear blade opened, the strip was then allowed to pass forwardly again and the loop was removed. Other systems have involved pairs of upper and lower shears which were mounted on rails and could move forwardly and backwardly along the axis of the sheet material. By accelerating the upper and lower shear dies to the speed of the sheet material, the dies could then be closed, without stopping the sheet material. The dies would then be opened up and stopped and returned to their starting position for the next cut. These systems were effective but the mechanism was complex and expensive. It was also difficult to achieve a precise location for the position of each cut. In addition, cuts of less than a predetermined length could not be achieved at all due to the fact that the shear dies had to move forwardly and backwardly once during each cut.
U.S. Pat. No. 2,445,174 involved rotary blades which essentially chopped the web material at predetermined locations. However, controlling the length of cut on these rotary choppers was difficult, since the length of cut depended on upon the diameter of the chopper drum, and the speed of the web requiring changes in gears.
Clearly there is a need for a rotary cutoff device which is capable of cutting moving web sheet material at predetermined locations, the locations being adjusted and pre-settable, and being operable even at over relatively short distances between cuts, and involving a minimum of complex machinery.
DISCLOSURE OF THE INVENTION
With a view therefore to achieving the foregoing improvements, the invention comprises a rotary cutoff apparatus for use in conjunction with a moving sheet web material, for cutting the same into predetermined lengths, and comprising, a pair of lower and upper cutoff rolls, and gear means interlocking said rolls for rotary movement in unison, the rolls defining a gap therebetween for movement of the sheet web material therethrough, selectively operable means for operating said lower and upper rolls whereby to rotate the same in unison, a stop bar on one of said lower and upper rolls, defining a cutoff location and, a moveable cutoff blade-on the other of said lower and upper rolls, and means for moving said cutoff blade towards and away from said stop bar, said cutoff blade being offset slightly with respect to said bar whereby said cutoff blade moves adjacent said bar and achieves a shearing action.
The invention further provides that the moveable cutoff blade is connected to at least three plunger members extending through said other of said rolls, cam means on said plungers, and cam operating means located outside said roll in registration with said cam means, whereby upon rotation of said roll, said cam means engage said cam operating means and cause said plungers to advance said cutoff blade towards said stop bar.
The invention will also preferably provide that the cutoff rolls may be started and stopped by means of power operated means such as a motor or a clutch means, which is connected to a length measurement device located upstream of the cutoff apparatus, for measuring the length of the web material and for sending signals to the power operated means.
It is an advantage if the cutoff blade is mounted at a slight shear angle relative to the stop bar, so as to provide a cutting action which starts at one side of the web and continues to the other side.
The two rolls are preferably of relatively small diameter, so that they may be started and stopped easily, and so the position of each cut may be precisely regulated.
The operation of the cutting blade is such that as soon as the cut is completed, the cutting blade is retracted once more, so that the upstream end of the web can continue passing between the rolls without obstruction.
The various features of novelty which characterize the invention are pointed out with more particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
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Formtek, Inc.
Rachuba M.
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