Claims
- 1. A machine for microcreping a running length of web comprising
- a driven roll,
- a stationary primary pressing surface for pressing the web against the surface of said roll to drive the web forward at a drive nip, and
- first and second generally stationary downstream web-contacting surfaces on sides of the web corresponding to said roll and primary surface, respectively, adapted to define an extrusion orifice to provide an extrusion retarding effect to the oncoming web, said second generally stationary downstream web-contacting surface being an extension of said stationary primary pressing surface,
- the driving and retarding of said web being adapted to cause its longitudinal compressive treatment in a cavity defined in the region of transition of the web from said roll to said downstream surfaces,
- that improvement wherein:
- the machine is adapted to treat the web in response to retarding forces produced by tangential extrusion,
- said first and second generally stationary downstream web-contacting surfaces defining an extrusion orifice (TEO) the axis X of which extends at an angle substantially parallel, i.e., at an angle less than 20.degree., to the tangent to the roll at the final point P of positive drive of the web, the extrusion resistance force R provided solely by the surfaces defining said orifice, serving to maintain a substantially straight retarded column of treated web material capable of resisting forward movement of material freshly driven by said roll, to cause said longitudinal compressive treatment of the web, said first web-contacting surface being defined by a generally plate-form blade member, said plate-form member being resiliently urged toward the driven nip by a force acting generally parallel to the tangent to the roll in the manner to enable resilient self adjusting movement of said plate member in its plane in response to operating conditions of said machine.
- 2. The machine of claim 1 wherein said second generally stationary downstream web-contacting surface defining said orifice is provided by a cantilevered integral continuation of said primary pressing surface.
- 3. The machine of claim 2 wherein said primary member comprises a sheet member of spring steel having a thickness of at least 0.010 inch.
- 4. The machine of claim 1 wherein the member defining said second web-contacting surface is capable of restricted flexing under treatment conditions to a curved shape in the direction opposite to that of the roll surface, to a curvature having a radius of the order of magnitude of the radius of the roll.
- 5. The machine of claim 1 wherein said first web-contacting surface lies in a plane which is substantially parallel to said tangent to the roll.
- 6. The machine of claim 1 wherein said first web-contacting surface is movable while remaining parallel to its original plane to gradually vary the geometry of said treatment cavity.
- 7. The machine of claim 6 wherein said movement of said first web-contacting surface is adapted to change slightly the alignment of the upstream edge thereof with respect to said roll surface.
- 8. The machine of claim 7 wherein said first web-contacting surface is mounted to enable it to pivot in the plane parallel to said surface to enable adjustment of the alignment of the upstream edge thereof.
- 9. The machine of claim 1 wherein said first web-contacting surface lies in a plane parallel to the direction of extent of said plate form member.
- 10. The machine of claim 1 wherein said first web-contacting surface lies at an angle to the direction of extent of said plate-form member.
- 11. The machine of claim 1 wherein the height of said treatment cavity gradually increases in the direction of web travel as a result of gradual, diverging curvature of both said roll and said overlying surface.
- 12. A method for microcreping a running length of web comprising pressing the web between the surface of a driven roll and a stationary primary pressing surface to drive the web forward at a drive nip, and
- providing an extrusion retarding effect to the oncoming web by employing first and second generally stationary web-contacting surfaces on sides of the web corresponding to said roll surface and primary surface, respectively,
- the driving and retarding of said web causing its longitudinal compressive treatment in a cavity defined in the region of transition of the web from said roll to said downstream surfaces,
- that improvement wherein:
- the web is treated by an extrusion resistance force formed solely by tangential extrusion between web-contacting surfaces comprising first and second generally stationary surfaces that define an extrusion orifice the axis of which extends substantially parallel, i.e., at an angle less than 20.degree., to the tangent to the roll at the final point P of positive drive of the web to maintain a substantially straight retarded column of treated web material capable of resisting forward movement of material freshly driven by said roll,
- the extrusion retarding effect is resiliently maintained by providing a plate-form member to provide said first web-contacting surface, and resiliently urging said plate-form member toward the drive nip by a force acting generally parallel to the tangent to the roll in the manner to enable resilient self-adjusting movement of said plate-form member in the direction of its plane in response to operating conditions of said process.
Parent Case Info
This application is a continuation of U.S. Ser. No. 803,059, filed Nov. 29, 1985, which is a continuation-in-part of U.S. Ser. No. 594,670, filed Mar. 29, 1984, both, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4422892 |
Plant |
Dec 1983 |
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Foreign Referenced Citations (1)
Number |
Date |
Country |
260721 |
Sep 1963 |
AUX |
Continuations (1)
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Number |
Date |
Country |
Parent |
803059 |
Nov 1985 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
594670 |
Mar 1984 |
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