Headbox for cylinder papermaking machine having flexible trailing elements therein and a flexible slice roof of tapering thickness

Claim 2

In a machine for forming a web from a fiber containing stock, the combination comprising, a rotatable porous forming roll for draining water from a slurry of stock deposited on the surface thereof and forming a web, a headbox for receiving stock under pressure extending along the roll and having a lower wall and an upper wall facing the roll and having a slice opening, said upper wall pivotally supported at its upstream edge, a curved roof member nonrigid in the direction of curvature mounted on the upper wall extending from the slice opening along the surface of the forming roll, and means for varying the curvature of said roof member during operation, including first and second power means at the leading and trailing edges of said roof member moving away from the roll along paths which extend in a converging angle toward each other so that said roof member bends and changes curvature about its length as it is moved toward or away from the roll.

Claim 3

In a machine for forming a web from a fiber containing stock, the combination comprising, a rotatable porous forming roll for draining water from a slurry of stock deposited on the surface thereof and forming a web, a headbox for receiving stock under pressure extending along the roll with a lower wall and an opposing upper wall facing the roll and having a slice opening at the downstream edges with the downstream edges extending substantially the same distance in the direction of the flow stream, a pivotal support for the upstream edge of the upper wall, said upper wall being rigid to be positioned by movement of its downstream edge, a curved roof member tapered in a downstream direction extending from the slice opening along the surface of the forming roll and pivotally attached to the downstream edge of the upper wall, the roof member having a predetermined curvature for optimum flow characteristics between the roof and forming roll, a cantilever support for one end of the roof member, and an adjustment means connected to the other end of the roof member for moving it toward or away from the roll to bend it about the cantilever support so that its curvature changes in different amounts along its length.

Claim 4

In a machine for forming a web from a fiber containing stock, the combination comprising, a rotatable porous forming roll for draining water from a slurry of stock deposited on the surface thereof and forming a web, a headbox for receiving stock under pressure extending along the roll with a lower wall and an opposing upper wall facing the roll and having a slice opening at the downstream edges with the downstream edges extending substantially the same distance in the direction of the flow stream, a pivotal support for the upstream edge of the upper wall, said upper wall being rigid to be positioned by movement of its downstream edge, a curved roof member tapered in a downstream direction extending from the slice opening along the surface of the forming roll and pivotally attached to the downstream edge of the upper wall, the roof member having a predetermined curvature for optimum flow characteristics between the roof and forming roll, a cantilever support for one end of the roof member, and an adjustment means connected to the other end of the roof member for moving it toward or away from the roll to bend it about the cantilever support so that its curvature changes in different amounts along its length.

Claim 5

In a machine for forming a web from a fiber containing stock constructed in accordance with claim 2, the combination wherein said roof member is cantilever supported at its upstream end, and the profile of the roof member is tapered along its length from an upstream to a downstream direction so that the forming zone between the roof member and roll will retain an optimum shape with changes in position of the downstream end of the roof member.

Claim 6

In a machine for forming a web from a fiber containing stock constructed in accordance with claim 2, the combination wherein said adjustment means and cantilever support include first force means for moving the upstream edge of said roof member toward or away from the roll, a second force means for moving the downstream edge of said roof member toward or away from the roll, and a third force member connected to both of said first and second force means for moving the entire roof member relative to the forming roll.

Claim 7

In a machine for forming a web from a fiber containing stock constructed in accordance with claim 2, wherein said adjustment means and cantilever support include a first support at the upstream edge of said roof, a second support at the downstream edge of said roof, and each support being rigidly connected to the roof so that as either support is moved in a direction toward or away from the roll the roof will bend about the other support, and first and second power means respectively connected to said supports for moving said supports in a direction toward or away from said forming roll.

Claim 8

In a machine for forming a web from a fiber containing stock, the combination constructed in accordance with claim 2, including a plurality of trailing flexible members extending in a cross-machine direction parallel to the roll within said headbox anchored at their upstream ends with their downstream edge self-positioned by forces of the stock flowing through the headbox.

Claim 9

In a machine for forming a web from a fiber containing stock constructed in accordance with claim 6, the combination including a plurality of elongate passages extending parallel to the flow of stock through the headbox positioned upstream of said flexible members.

Claim 10

In a machine for forming a web from a fiber containing stock constructed in accordance with claim 6, the combination wherein said flexible members are continuous in a cross-machine direction.