Device for controlling the web tension in a running material web

Patent metadata

Field	Value
Publication number	US-10138087-B2
Application number	US-201415106636-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 20, 2013
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

Device and method for controlling axial forces acting upon a moving web comprises first, second and third rotatable rollers. The third roller is between the first and second rollers and is movable in a circular path in the vertical plane between lower and upper positions in response to axial forces acting at any moment upon the web. To enable a simple manual installation of the web, the upper position of the third roller is at a sufficient vertical distance above the first and second rollers to form an open horizontal passage through which the web can pass freely between the first and second rollers and the above-situated third roller. Axial forces are controlled by biasing the third roller with a force which counters the motion of the third roller in the direction of the upper working position and which is less than the ultimate tensile strength of the web.

First claim

The invention claimed is:

1. A device for controlling axial forces acting upon a web which is unwound from a horizontal rotatable shaft and is led up to and wound onto a corresponding horizontal rotatable shaft, wherein the device comprises a first roller, which is rotatable about a first horizontal shaft, a second roller, which is rotatable about a second horizontal shaft, and a third roller, which is rotatable about a third horizontal shaft, wherein the third roller is placed between the first and second rollers and is movable along an arc-shaped motional path in the vertical plane between a lower position and an upper position in response to axial forces acting at any moment upon the web, wherein the web is intended to be led with one side in contact with the first and second rollers and with another side in contact with the third roller, wherein the third roller, in the upper position, is at a vertical distance above the first and second rollers to form an open horizontal passage through which the web can pass freely between the first and second rollers and the above-situated third roller, wherein the third roller is biased with a force which counters the motion of the third roller in the direction of the upper working position and which is less than an ultimate tensile strength of the web.

2. The device according to claim 1 , wherein the third roller is pivotably suspended on a fourth horizontal rotatable shaft via arms, the one ends of which are connected to respective axial ends of the fourth horizontal shaft and the other ends of which are connected in a corresponding manner to respective axial ends of the third horizontal shaft.

3. The device according to claim 2 , wherein the fourth horizontal shaft is located at a higher level in the vertical plane than the first and the second horizontal shafts.

4. The device according to claim 2 , wherein the arms are substantially horizontal when the third roller is in the upper position.

5. The device according to claim 1 , wherein the arms are substantially horizontal when the third roller is in the upper position.

6. The device according to claim 1 for controlling axial tensile and yield forces acting at any moment upon a web of a packaging material which is unwound from the horizontal rotatable shaft and is led up to and wound onto the corresponding horizontal shaft and which, as the packaging material passes between the two horizontal shafts, is subjected to at least one slowdown and stoppage with a subsequent accelerating start in motion.

7. A method for controlling axial forces acting upon a web which is unwound from a horizontal rotatable shaft and is led up to and wound onto a corresponding horizontal rotatable shaft, comprising:
leading the web with it its one side into contact with a first roller and second roller, the first and second rollers being rotatable around a first and second horizontal shafts, respectively;
lowering a third roller, rotatable around a third horizontal shaft from a sufficient vertical distance above the first and second rollers to form an open horizontal passage through which the web can pass, into contact with the web, such that the third roller contacts the web at a side different from the one side in contact with the first and second rollers; and
biasing the third roller with a force to counter motion of the third roller in the direction of the upper working position, where the force is less than an ultimate tensile strength of the web.

8. A device operable together with a repair unit that removes faults and defects in a packaging material web and that is positioned between one horizontal rotatable shaft and another horizontal rotatable shaft to control axial forces acting upon a packaging material web which is unwound from the one horizontal rotatable shaft passed though the repair unit and the wound onto the other horizontal rotatable shaft, the packaging material web possessing an ultimate tensile strength and also including oppositely facing first and second sides, the device comprising:
a first roller rotatable about a first horizontal shaft;
a second roller rotatable about a second horizontal shaft that is spaced from the first horizontal shaft;
a third roller rotatable about a third horizontal shaft that is spaced from the first horizontal shaft and the second horizontal shaft;
the third roller being vertically movable, in response to axial forces acting at any moment on the web, along an arc-shaped movement path that passes between the first and second rollers so that the third roller is movable between an upper position and a lower position;
the first roller being positioned relative to the one horizontal rotatable shaft such that the first side of the packaging material web contacts the first roller as the packaging material web is being unwound from the one horizontal rotatable shaft;
the second roller being positioned relative to the other horizontal rotatable shaft such that the first side of the packaging material web contacts the second roller as the packaging material web is being wound onto the other horizontal rotatable shaft;
the third roller being positioned to contact the second side of the packaging material web, the third roller in the upper position is spaced vertically above the first and second rollers by a distance forming an open horizontal passage through which the packaging material web is freely passable between the first and second rollers while the third roller is vertically above the horizontal passage,
the third roller being biased by a force which counters motion of the third roller in a direction of the upper working position and which is less than an ultimate tensile strength of the packaging material web.

9. The device according to claim 8 , wherein the third roller is pivotably suspended on a fourth horizontal rotatable shaft by way of arms, the arms each possessing one end connected to respective axial ends of the fourth horizontal rotatable shaft, and the arms each possessing an opposite end connected in a corresponding manner to respective axial ends of the third horizontal shaft.

10. The device according to claim 9 , wherein the fourth horizontal shaft is positioned higher, in a vertical plane, than the first and the second horizontal shafts.

11. The device according to claim 9 , wherein the arms are substantially horizontal when the third roller is in the upper position.

Assignees

• Tetra Laval Holdings & Finance

Inventors

• Pettersson Thomas
• Andersson Ingvar
• Öhman Peter

Classifications

• B65H2402/31

  Pivoting support means · CPC title

• B65H23/16 Primary

  by weighted or spring-pressed movable bars or rollers · CPC title

• B65H20/34

  with rollers · CPC title

• B65H2301/522

  Threading web into machine · CPC title