Manufacturing container or tube from paper; or other manufacturi – Control means energized in response to activator stimulated... – Responsive to work material – the product or means engaging...
Reexamination Certificate
1999-12-23
2003-11-04
Kim, Eugene (Department: 3721)
Manufacturing container or tube from paper; or other manufacturi
Control means energized in response to activator stimulated...
Responsive to work material, the product or means engaging...
C493S013000, C493S023000, C493S420000, C493S421000
Reexamination Certificate
active
06641514
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a buckle folding unit or pocket folding unit having an adjustable folding pocket. The invention also relates to a method for controlling the register of a buckle folding unit.
Heretofore known buckle folding units have three folding rollers which are jointly driven and rotate at the same speed, and a folding pocket. The folding rollers are essentially arranged at the corners of a right-angled triangle, the two folding rollers that are disposed vertically above one another conveying the incoming sheet into the folding pocket as far as a pocket stop that is adjustable as desired. The sheet is conveyed into the pocket at a travel speed that is matched to the composition of the paper. When the leading edge of the sheet strikes the pocket stop, and if the sheet is simultaneously conveyed further, a suspended buckle fold is formed in the buckling space between the three folding rollers, and the fold is gripped by the two folding rollers which are disposed horizontally beside one another and rotate in opposite directions. As the buckle fold passes through the folding rollers, the fold is then formed. The pocket stop, the width of the folding pocket and the position of the pocket mouth and of the pocket lips in relation to the buckling space have to be adjusted to the quality of the paper that is used and to the sheet format. These adjustments must also be made if the atmospheric humidity changes, because the stiffness of the paper is changed thereby. Furthermore, a change in the production speed has the effect of a change in the deformation of the sheet in the folding pocket and in the buckling space, so that the position of the fold on the sheet is displaced, and the folding unit may possibly have to be readjusted. The positional deviation of the fold on the sheet can, in this regard, only be detected on the finished folded sheet.
2. Summary of the Invention
It is an object of the invention to provide a buckle folding unit with which deviations of the fold position on a folded sheet can be detected during production. It is, furthermore, an object of the invention to provide a buckle folding unit with which control of the position of the fold on the sheet is made possible. It is also an object of the invention to provide a method for controlling the register of a buckle folding unit which ensures a constant position of the fold on the sheet in the event of a change in the production speed or paper stiffness.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a buckle folding unit with a folding pocket having an adjustable pocket stop, comprising a first detector for detecting a first instant as a sheet travels from an inlet to the buckle folding unit until it reaches the pocket stop, a second detector for detecting a second instant as the sheet travels from a formation of a fold as far as an outlet from the folding pocket, and a device for determining a length of the sheet conveyed between the first and the second instants.
In accordance with another feature of the invention, the first detector serves for detecting entry of the sheet into the buckle folding unit.
In accordance with a further feature of the invention, the first detector for detecting entry of the sheet into the buckle folding unit has at least one optical sensor.
In accordance with an added feature of the invention, the folding pocket has a pocket mouth with a lower lip, and the second detector serves for detecting a deflection of the pocket lower lip as the fold is formed.
In accordance with an additional feature of the invention, the second detector serving for detecting the deflection of the pocket lower lip is constructed as a displacement detector.
In accordance with yet another feature of the invention, the second detector serving for detecting the deflection of the pocket lower lip has at least one optical sensor.
In accordance with yet a further feature of the invention, the second detector serving for detecting the deflection of the pocket lower lip has a wire strain-gauge device on the pocket lower lip.
In accordance with yet an added feature of the invention, the second detector serving for detecting the deflection of the pocket lower lip has a piezo-electric sensor disposed on the pocket lower lip.
In accordance with yet an additional feature of the invention, the first detector serves for detecting entry of the sheet into the folding pocket, and the second detector serves for detecting exit of the sheet from the folding pocket.
In accordance with still another feature of the invention, the folding pocket has a pocket mouth, and the first and the second detectors, respectively, serving for detecting entry and exit of the sheet, are arranged at the pocket mouth.
In accordance with still a further feature of the invention, the first and the second detectors, respectively, serving for detecting entry and exit of the sheet have a common optical sensor.
In accordance with still an added feature of the invention, the device for determining the length of the sheet conveyed between the first and the second instants has a pulse generator assigned to a folding roller, and a counting device.
In accordance with still an additional feature of the invention, the first detector for detecting the first instant serves for detecting a leading edge of the sheet at a defined position on a sheet path, and the second detector for detecting the second instant serves for detecting a folded edge of the sheet that has been folded.
In accordance with another feature of the invention, the second detector for detecting the folded edge of the sheet that has been folded includes a light barrier having a transmitter for emitting electromagnetic radiation and an associated receiver for receiving the electromagnetic radiation.
In accordance with a further feature of the invention, a straight connecting line between the transmitter and the receiver is disposed at an angle to the axes of the folding rollers.
In accordance with an added feature of the invention, the second detector for detecting the folded edge of the sheet that has been folded includes a light barrier having a laser-light transmitting unit and a laser-light receiver.
In accordance with an additional feature of the invention, the folding pocket is adjustable and has at least one electrically activated actuating device, and the buckle folding unit includes a control unit for processing signals from the first detector for detecting the first instant, the second detector for detecting the second instant, and the device for determining the length of the sheet conveyed between the first and the second instants, the electrically activated actuating device of the folding pocket being drivable by the length-determining device.
In accordance with yet another feature of the invention, the buckle folding unit includes a folding pocket stop adjustable by the electrically activated actuating device.
In accordance with yet a further feature of the invention, the folding pocket has a width that is adjustable by the electrically activated actuating device.
In accordance with yet an added feature of the invention, the buckle folding unit includes at least one folding pocket adjustable by the electrically activated actuating device.
In accordance with yet an additional feature of the invention, the folding pocket has a folding pocket mouth displaceable by the electrically activated actuating device for varying a buckling space in the folding pocket.
In accordance with still another feature of the invention, the control unit has a microprocessor.
In accordance with still a further feature of the invention, the buckle folding unit includes at least one optical sensor for detecting a start of a printed image on an incoming sheet.
In accordance with still an added feature of the invention, the control unit serves also for processing a signal from the optical sensor for detecting the start of a printed image.
In accordance with another aspect of the invention
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Kim Eugene
Locher Ralph E.
Stemer Werner H.
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