Patent SE-513435-C2 (SE)
Title: Headbox for paper machine has center of pivot arranged in proximity to plumbline of axis of gravity and between plumbline and slice opening
Inventor: HARALDSSON NILS ULF
IPC: D21F1/02
Filed: 1999-01-21
Abstract: The headbox has a center of pivot (Hc) arranged in the proximity to the plumbline of the axis of gravity (Ga), which is between the plumbline and slice opening (18) so as to load the outer setting unit (34) by weight of a corresponding lesser portion of headbox. The outer setting unit has an eccentric portion and a mechanical actuator.  The mechanical actuator is arranged on the eccentric portion for stepless pivoting of the headbox about the center of pivot. The headbox is arranged in the wet section having a forming roll (4) with forming wires (3,5) defining a wedge shaped inlet gap (7). The headbox has a slice (10) with a slice opening, located in the wedge shaped inlet gap for discharging a single or multi-layered jet of stock (19). The stock has a certain geometry relative to a forming zone (8) of the forming roll. The headbox is supported by a machine stand (70) and has opposing support arm (23) and bearing housing (27) for creating a fixed center of pivot during operation. The center of pivot is parallel to the axis of rotation (Fa) of the forming roll. A central setting unit (30) is arranged between the machine stand and bearing housing for parallel movement of center of pivot and corresponding adjustment of the discharge opening in relation to the forming zone. The outer setting unit is arranged at a distance from the central setting unit to the distance between an outer portion of the headbox and machine stand. The outer setting unit is arranged in the middle of the rearward end wall of the headbox at an equal distance from side walls of the headbox to the slice opening, extending along machine direction. The outer setting unit has bearing housings, a pivoting shaft, a link and connecting system. The eccentric portion is connected with the headbox. The pivoting shaft is journalled in the bearing housing. The mechanical actuator is arranged to turn the pivoting shaft for transforming a rotary motion into a linear motion in the link and connection system through the eccentric position. The pivoting shaft is extended parallel to the center of pivot of the headbox or at right angles. The eccentric portion has two coaxial eccentric journal eccentrically rigidly connected to the pivoting shaft. Two link arms of the link and connecting system is pivoted to the eccentric journal and to the headbox. The mechanical actuator includes a lever and an extendible screw connected to lever at an angle to the same and to a counter support in the machine stand. A tool is arranged to act manually to increase or decrease the distance between the lever and the rigid counter support. The screw is of shroud type with opposite screw pins. The central setting unit has one pair arranged to operator and drive side respectively to move the center of pivot in parallel direction of jet of stock. Another pair is arranged similarly but to move perpendicular to the previous direction. The inner forming wire runs in direct contact with the forming roll. An Independent claim is also included for setting device for headbox.