Rotary knife with active vibration control
First Claim
1. A rotary knife for cutting a plurality of individual sheets in succession from a longitudinally traveling continuous web of material, the rotary knife comprising:
- a frame;
a first tubular rotatable knife cylinder and a second tubular rotatable knife cylinder, each of the tubular knife cylinders having a blade mounted on an outer cylindrical wall of the respective knife cylinder, the blades engaging each other as the tubular knife cylinders rotate to cut the web;
a first stationary support shaft located concentrically within the first tubular knife cylinder and fixed to the frame;
support bearings located between the first stationary support shaft and the first tubular knife cylinder to rotatably support the first tubular knife cylinder on the first stationary support shaft; and
an active tuned mass damping system for the first knife cylinder includinga tuned mass,a spring arm having one end coupled to the tuned mass and another end coupled to the first stationary support shaft,a knife vibration sensor that monitors vibration of the first knife cylinder and generates a signal in response thereto,a tuned mass vibration sensor that monitors vibration of the tuned mass and generates a signal in response thereto,an electronic control unit that inputs the signals from the first knife vibration sensor and the tuned mass vibration sensor and outputs one or more command signals, andan actuator that provides a force on the tuned mass in response to the one or more command signals from the electronic control unit.
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Accused Products
Abstract
A rotary knife incorporates the use of an electronically controlled, tuned mass active damping system to control vibrations of the knife cylinder. The system preferably uses one or more electromagnetic actuators to provide force on a tuned mass which is mechanically coupled to the knife cylinder. Vibration sensors, preferably accelerometers, are used to monitor vibrations of the respective knife cylinders and tuned masses. A digital signal processor implementing a state space control system controls the electromagnetic actuators to remove vibration energy from the system. An active damping system in accordance with the invention is more effective in removing vibration energy than passive systems, especially in heavy-duty applications.
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Citations
51 Claims
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1. A rotary knife for cutting a plurality of individual sheets in succession from a longitudinally traveling continuous web of material, the rotary knife comprising:
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a frame; a first tubular rotatable knife cylinder and a second tubular rotatable knife cylinder, each of the tubular knife cylinders having a blade mounted on an outer cylindrical wall of the respective knife cylinder, the blades engaging each other as the tubular knife cylinders rotate to cut the web; a first stationary support shaft located concentrically within the first tubular knife cylinder and fixed to the frame; support bearings located between the first stationary support shaft and the first tubular knife cylinder to rotatably support the first tubular knife cylinder on the first stationary support shaft; and an active tuned mass damping system for the first knife cylinder including a tuned mass, a spring arm having one end coupled to the tuned mass and another end coupled to the first stationary support shaft, a knife vibration sensor that monitors vibration of the first knife cylinder and generates a signal in response thereto, a tuned mass vibration sensor that monitors vibration of the tuned mass and generates a signal in response thereto, an electronic control unit that inputs the signals from the first knife vibration sensor and the tuned mass vibration sensor and outputs one or more command signals, and an actuator that provides a force on the tuned mass in response to the one or more command signals from the electronic control unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A rotary knife for cutting a plurality of individual sheets in succession from a longitudinally traveling continuous web of material, the rotary knife comprising:
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a frame; a first rotatable knife cylinder and a second rotatable knife cylinder, each of the rotatable knife cylinders having a blade mounted on an outer cylindrical wall of the respective knife cylinder, the blades engaging each other as the knife cylinders rotate to cut the web; and an active tuned mass damping system for the first knife cylinder including; a tuned mass coupled to the first rotatable knife cylinder, a knife vibration sensor that monitors vibration of the first knife cylinder and generates a signal in response thereto, a tuned mass vibration sensor that monitors vibration of the tuned mass and generates a signal in response thereto, an electronic control unit that inputs the signals from the knife vibration sensor and the tuned mass vibration sensor and outputs one or more command signals, and an actuator that provides a force on the tuned mass in response to the one or more command signals from the electronic control unit. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification