WO2007096458A1

WO2007096458A1 - Method and apparatus for inserting a plug into a material web roll

Info

Publication number: WO2007096458A1
Application number: PCT/FI2007/000041
Authority: WO
Inventors: Matti Lammi
Original assignee: Raumaster Paper Oy
Priority date: 2006-02-27
Filing date: 2007-02-21
Publication date: 2007-08-30
Also published as: FI20060191A; SE0801796L; SE532480C2; FI20060191A0; FI119367B

Abstract

The invention relates to a method for inserting plugs into a tubular core (2) with material web, such as cardboard or paper web reeled around it. The invention also relates to an apparatus for inserting plugs into a tubular core. The plug applicator (27) is first aligned with respect to a calculated position of the opening of the tubular core (2), whereupon the material web roll (1) and the plug applicator (27) are brought into loose contact with each other. Next, the plug applicator (27) is aligned with the core opening according to its actual position, and the alignment is locked. Finally, the plug applicator (27) inserts a plug (3a) into the core opening of the material web roll (1).

Description

Method and apparatus for inserting a plug into a material web roll

The present invention relates to a method for inserting plugs into a tubular sleeve with material web, such as cardboard or paper web reeled around it. The invention also relates to an apparatus for inserting plugs into a tubular sleeve.

Plugs are used to prevent deformations of the roll during handling and transfers. The plugs play an important role especially when tubular sleeves made of soft material are used, and in the case of sleeves with a large diameter. With cardboard rolls, 12" sleeves are generally used.

If the plug can be inserted into the tubular sleeve already before the slitter, then this is a fairly simple task. Exact positioning of the sleeve can be achieved by simple means. Relevant solutions are described e.g. in patent specifications WO 8605443 and US 4716646. Tubular sleeves having no material web around them can be plugged before a slitter primarily in paper factories, where sleeves of a small diameter, typically 3" and 6", are used.

The task is substantially more complicated when a plug has to be inserted into a tubular core inside a roll. In this case, problems are caused e.g. by the following factors:

- The tubular core of the material web roll can not be sufficiently accurately positioned in the plug application position without expensive special arrangements. In respect of the amount of equipment required, an advantageous insertion position is when the roll is placed on a V- lamella conveyor. However, the roll may perhaps be in a slightly oblique position relative to the direction of motion. Likewise, in practice the material web roll is not absolutely round nor completely symmetrical relative to the tubular core. - The plug fulfills its function best when the plug and core have an interference fit between them. In the tightest cases, the required insertion force may amount to over 10 000 Newton. Additionally, as the size of the chamfer and/or clearance facilitating the application of the plug is to be minimized for reasons of material saving etc., very precise alignment is required.

- The material web roll may have a diameter of over two meters. The insertion force acts at a fairly large distance from the structures on which the plug applicators are supported.

In practice, the application of the plug is performed manually. The operator inserts the plug in an oblique position into the tubular core so that the plug is wedged in place. After this, the operator strikes on the plug with a large smith's hammer until the plug has moved into the desired alignment and position. This is a hard job and engages expensive human resources. Often the plug also remains in an oblique position and is therefore deficient in respect of protective effect.

The object of the present invention is to disclose a compact solution that enables the plug to be automatically inserted in an optimal position into a material web roll. The solution is simple and reliable. The plug mounting apparatus of the invention is able to adapt itself to the inaccuracy remaining after computational alignment into position. This inaccuracy may be + - 5 - 10 mm. Striving at the initial stadium after a better alignment accuracy, which could be reached at least in theory, would lead to the application of very expensive technology. Furthermore, in the solution of the invention no expensive equipment for centering the material web roll is needed.

In more precise terms, the invention is characterized by what is presented in the characterization parts of the independent claims. In the following, the invention will be described by referring to the attached drawings, wherein

Fig. 1 presents a plug applicator aligned according to the opening of the core of a material web roll and ready to insert a plug into the core, in a partially sectioned view along the axis of revolution of the core of the roll.

Fig. 2 presents the plug applicator in an aligning situation, in a partially sectioned view along the axis of revolution of the core of the roll.

For the sake of readability, the figures are not in scale in all respects.

The structure of a preferred embodiment of the invention is as follows. Using the equipment described above, the plug applicators 27 are first roughly aligned relative to the calculated positions of the openings of the tubular core 2 of the material web roll 1.

Calculated position of the openings of the tubular core 2 refers to the following. When the material web roll 1 is placed e.g. on a V-lamella conveyor or centered in a corresponding manner, the axis of revolution of the core 2 is assumed to be located in a vertical plane intersecting the longitudinal symmetry axis of the V- lamella conveyor or corresponding centering means. In the vertical direction, the determination of position is based on a measurement of the diameter of the material web roll 1 and the assumption that the axis of revolution of the tubular core 2 is located at the theoretical center of the material web roll 1.

The position of the plug applicator 27 relative to the tubular core 2 of the material web roll 1 in the direction of the axis of revolution of the core / roll is varied via movement of bearing units 6 and a carriage 28 moving along guide rails 5 on the frame 4. The position of the plug applicator 27 relative to the tubular core 2 of the material web roll 1 in the vertical direction is varied via movement of bearing units 8 moving along guide rails 7 mounted on carriage 28 and a carriage 9 attached to the said bearing units 8.

The power units for both vertical and horizontal motion are implemented using technology known in itself, such as a gear motor and a cogged belt, which are not described. Using the equipment described in the following, the plug applicator 27 is aligned relative to the actual positions of the openings of the core 2.

The plug applicator 27 is floatingly supported on carriage 9. The floating motion is arranged to take place in a plane transverse to the axis of revolution of the tubular core 2 of the material web roll 1. In the vertical direction, the plug applicator 27 moves floatingly according to the motion of bearing units 11 and a carriage 12 moving along guide rails 10. In the horizontal direction, the plug applicator 27 moves floatingly according to the motion of bearing units 16 and a carriage 17 moving along guide rails 15.

A plug inserting element 22 is moved in the direction of the axis of revolution of the tubular core 2 by a power means 20 as guided by bearing units 19 moving along guide rails 18. The power means 20 is preferably a pneumatic cylinder. The pneumatic cylinder is preferably provided with a piston rod which goes through the cylinder and, at its end pointing towards the roll 1 , is fastened to the inserting element 23. An additional weight 21 may be attached to the other end of the piston rod.

Attached to the plug inserting element is a centering element 23, which preferably is a cone which tapers towards the tubular core 2 and whose axis of revolution extends in the same direction with the axis of revolution of the core 2. Attached to carriage 17 so as to be movable with it is a guiding element 24, whose guide surface consists of one or more sectors, wedges or equivalent forming parts of a cone tapering towards the tubular core 2. These guide surfaces are located in a sector below the axis of revolution of the centering element 23. The upper half is open. The axes of revolution of the cones of the centering element 23 and the guiding element 24 are concentric. The radius of the cone of the guiding element 24 at the end facing towards the tubular core 2 is equal to the radius of the inner surface of the core. The guiding element surface adjacent to the core is provided with a friction surface 25, e.g. a rubber sheet.

Mounted on carriage 17 so as to be movable with it is also a magazine 29, which is provided with guiding elements that guide the plug into the space between the plug inserting element/centering element and the material web roll. The magazine may contain one or more plugs 3b awaiting their turn to be inserted. The plugs are prevented from falling down by a stopper 26, e.g. a pneumatic cylinder. Plugs may be added into the magazine manually or e.g. by an industrial robot.

In the embodiment described here, the centering of the plug applicator 27 in both horizontal and vertical directions is implemented using pneumatic cylinders, but it can also be implemented using springs or equivalent power means. In the vertical direction, the force applied to the plug applicator by the upper centering element 13 is smaller than the force applied by the lower centering element 14. This compensates for the weight of the plug applicator 27. The difference between the forces can be achieved by using differently sized centering elements, unequal pressures, counterweights or by some other known method.

The solution of the invention works as follows. Using devices known in themselves bun not shown in the figure, the material web roll 1 is brought to a position between two plug applicators 27 such that vertical motion of the axis of revolution of the centering element 23 of the plug applicator roughly takes place in a vertical plane intersecting the axis of revolution of the tubular core 2. The diameter of the roll 1 is measured using prior-art technology, e.g. an ultrasound or laser measuring device. Likewise by using prior-art technology, measuring the distance by means of e.g. a pulse transducer or an absolute detector, the plug applicator is moved vertically until the axes of revolution of the centering element 23 and tubular core 2 are at about the same height. This procedure is followed for both of the two applicators on either side of the roll. Considering the inaccuracy caused by several factors, the centering elements 23 are thus brought to a position concentric with the axis of revolution of the tubular core 2 with an accuracy of a few millimeters at best.

Next, the plug applicators are moved towards the material web roll and either left just barely clear of the roll or brought into loose contact with it, so that there remains no pressure between the plug applicator and the roll as this would give rise to a frictional force inhibiting transverse motion. After this, the plug applicators 27 are automatically aligned with the core openings according to their actual positions. The alignment of the plug applicator 27 relative to the actual positions of the openings of the tubular core 2 takes place when the centering element 23 is moving towards the tubular core 2 of the material web roll in the direction of its axis of revolution, so that, while the plug applicator 27 is floating in a plane transverse to the axis of revolution of the core 2, the centering surfaces of the centering element 23 exert a wedging effect on the centering element 23, forcing it to assume a position concentric with the axis of revolution of the tubular core 2.

Described in greater detail, automatic application of a plug into a roll is performed as follows. The power means 20 pushes the centering element 23 into the tubular core 2, into the position shown in Fig. 2. Due to the conical surface of the centering element 23 and the floatability of the plug applicator 27, the axes of revolution of both the centering element 23, the guiding element 24 and the tubular core 2 become concentric, i.e. mutually aligned. After this, the alignment is locked by moving the plug applicators 27 against the ends of the tubular core 2 and/or material web roll 1 in such manner that a pressure remains between the plug applicator and the material web roll and the alignment is preserved by virtue of the friction surface 25 / frictional force. The power means 20 now pulls the centering element 23 of the plug inserting element 22 out of the core 2. The stopper 26 lets a plug fall down from the magazine 29 into the space between the centering element 23 and the core 2. Mechanisms placed higher above, which are not shown in the figure, may now drop a new plug 3b into the magazine, but this can also be done at a later stage. This situation is illustrated in Fig. 1. Next, the power means 20 pushes/strikes the plug 3a in front of the centering element 23 of the plug inserting element 22 to force the plug into the core 2. The plug applicator 27 is provided with a sensor to indicate whether the plug has been inserted sufficiently deep into the tubular core. The sensor may be placed e.g. on the surface of the power means 20 to measure the position of the piston e.g. by a magnetic method.

If the plug 3a and the tubular core 2 have a particularly tight fit between them, then the normal thrust of the power means is not necessarily sufficient. In this case, the pneumatic cylinder 20 used as a power means is operated as a pneumatic hammer. By exhausting air from the chamber next to the plug inserting element before feeding air into the chamber on the other side of the piston, an impact movement is produced. The impact power can be further enhanced by using an additional weight 21.

Many other embodiments are possible. In another embodiment, the linear movements are completely or partly replaced with joint structures. In an embodiment of the invention, the material web roll 1 is placed on a turntable. In this case, one plug applicator 27 is sufficient to insert plugs into either end of the material web roll 1. The plug applicator 27 is located in a fixed position beside the turntable.

In this case, too, automatic rough centering of the plug applicator 27 with respect to the calculated position of the opening of the tubular core 2 of the material web roll 1 is first performed.

The material web roll 1 is turned on the turntable into an angular position such that vertical motion of the axis of revolution of the centering element 23 of the plug applicator roughly takes place in a vertical plane intersecting the axis of revolution of the tubular core 2. The diameter of the roll 1 is measured as described above and the plug applicator is moved vertically until the axes of revolution of the centering element 23 and core 2 are at about the same height. After this, the material web roll 1 and the plug applicator 27 are brought into loose contact with each other. Preferably the material web roll 1 is moved against the plug applicator 27 so that there remains no pressure between them. After the alignment has been completed, automatic application of the plug is carried out in the manner described above. Next the material web roll 1 is moved clear of the plug applicator 27, the turntable is rotated through 180 degrees and a plug is automatically inserted into the other end of the material web roll 1 as described above. In the last described embodiment, no mechanism 5, 6 permitting movement of the plug applicator in the direction of the axis of revolution of the material web roll 1 is needed at all.

Further, an embodiment of the invention comprises no guiding element 24 at all, but the plug is dropped from the magazine into a position where the plug 3a, with respect to its axis of revolution, is already concentric with the axis of revolution of the core 2 of the roll 1.

Claims

1. Method and apparatus for inserting a plug into a tubular core (2) inside a material web roll (1), characterized in that a plug applicator / plug applicators (27) are first aligned automatically with respect to a calculated position / calculated positions of the opening / openings of the tubular core (2) of the material web roll (1); next, the material web roll (1) and the plug applicator (27) are brought into loose contact with each other; - next, the plug applicator / plug applicators (27)/plug/plugs (3a) are automatically aligned with the core opening / core openings according to its/their actual position, and the alignment is locked; after this, the plug applicator / plug applicators (27) automatically inserts/insert a plug/plugs (3a) into the core openings of the material web roll (1).

2. Method according to claim 1 , characterized in that the alignment of the plug applicator (27) relative to the actual positions of the openings of the tubular core (2) takes place when a centering element (23) is moving towards the tubular core (2) of the material web roll in the direction of its axis of revolution, so that, while the plug applicator (27) is floating in a plane transverse to the axis of revolution of the tubular core (2), the centering surfaces of the centering element (23) exert a wedging effect on the centering element (23), forcing it to assume a position concentric with the axis of revolution of the tubular core (2).

3. Method according to any one of the preceding claims, characterized in that the plug is supplied automatically from a magazine (29) into the space between a plug inserting element / centering element (23) and the tubular core (2).

4. Method according to any one of the preceding claims, characterized in that a power means (20) pushing the plug (3a) into the tubular core (2) generates impacts to enhance the inserting force.

5. Method according to any one of the preceding claims, characterized in that plugs are supplied into the magazine (29) by an industrial robot.

6. Method according to any one of the preceding claims, characterized in that plugs are supplied manually into the magazine (29).

7. Method according to any one of the preceding claims, characterized in that the material web roll (1) is placed on a turntable, and one plug applicator (27) is used to insert plugs into either end of the material web roll (1).

8. Apparatus for inserting a plug into a tubular core (2) inside a material web roll (1), characterized in that the apparatus comprises means for performing automatic alignment of a plug applicator / plug applicators (27) with respect to a calculated position / calculated positions of the opening/openings of the tubular core (2) of the material web roll (1); - means for bringing the material web roll (1) and the plug applicator

(27) into loose contact with each other; means for automatically aligning the plug applicator / plug applicators (27) and the plug (3a) with the core opening / core openings according to its/their actual position, and means for locking the alignment; - a means / means for automatically inserting a plug/plugs (3a) into the opening/openings of the tubular core (2) of the material web roll (1).

9. Apparatus according to claim 8, characterized in that, to enable the plug applicator/applicators (27) to be aligned according to the actual positions of the openings of the tubular core (2), it comprises en element/elements permitting a floating motion of the plug applicator (27) in a plane transverse to the axis of revolution of the tubular core (2), and a centering element / centering elements (23), whose centering surfaces exert a wedging effect on the centering element (23), forcing it to assume a position concentric with the axis of revolution of the tubular core (2).

10. Apparatus according to any one of the preceding claims, characterized in that the power means (20) producing a thrust/impact to force the plug (3a) into the tubular core (2) is a pneumatic hammer.