WO2007084048A1

WO2007084048A1 - Method and arrangement for improved wrapping

Info

Publication number: WO2007084048A1
Application number: PCT/SE2006/050623
Authority: WO
Inventors: Mats Eriksson
Original assignee: Bergs Engineering Ab
Priority date: 2006-01-18
Filing date: 2006-12-22
Publication date: 2007-07-26
Also published as: EP1979107B1; EP1979107A4; SE0600120L; EP1979107A1; SE529858C2

Abstract

An arrangement for wrapping an end of a coilable material (1) on a mandrel (2), comprises forming means (3) with first (3a) and second (3b) contact means rotatably connected to said forming means (3) and rigidly connected to each other via first connection means (3c), said contact means (3a, 3b) are adapted for contacting a surface of said material (1), such that the first and second contact means (3a, 3b) bring at least a section of the material (1) into contact with an outer surface of the mandrel (2), said forming means (3) are further adapted to maintain said contact means (3a, 3b) in contact with the surface of the material and to rotate a predetermined angle around the central axis of the mandrel (2) to wrap the end of the material (1) around the outer surface of the mandrel (2).

Description

METHOD AND ARRANGEMENT FOR IMPROVED WRAPPING

TECHNICAL FIELD

The present invention concerns sheet wrapping in general, especially methods and arrangements for improved initial wrapping of the end of a steel sheet on a mandrel.

BACKGROUND

During manufacture of strip steel, several problem areas need to be taken into account. First of all the strips are wound/ wrapped/ coiled on and off several different types of mandrels /coilers. During coiling, it is important to secure the first end of the strip to the mandrel/ coiler drum. Known methods of doing so include attaching a "clamping slot" which clamps the first end as the mandrel is expanded to its nominal diameter; this requires a manual step and will deform the end of the strip.

Known methods of solving the above-mentioned problem include pressing a driven belt against the mandrel. The belt shapes itself against the mandrel thus handling the free end of the strip and stays in contact with the mandrel for a few rotations until the laps lock each other. This known type of belt wrappers does solve the problem of securing the end of the strip without a manual operation, but they are costly and space consuming equipment.

Therefore, there is a need for an arrangement that enables securing the first end of a strip to a mandrel in a more cost and space efficient manner.

SUMMARY

An object of the present invention is to provide methods and arrangements for wrapping material around a mandrel.

A further object is to provide improved wrapping of sensitive materials. Another object is to provide a space efficient wrapper for coilable material.

Yet another object is to provide a pivoting roller wrapper.

These and other objectives are achieved according to the attached claims.

A first aspect the invention comprises a wrapper arrangement with a forming tool comprising two contact organs for contacting the surface of the material to be wrapped and bringing at least a section of the material into contact with a mandrel. The forming tool is further adapted to be able to rotate around the central axis of the mandrel and in coordination with the rotation of the mandrel to enable and maintain contact between the material and the outer surface of the mandrel until the end of the material is securely fastened between the incoming material and the outer surface of the mandrel.

According to a second aspect of the invention, at least the surfaces of the contact means and/ or the mandrel comprise an elastic material to reduce the risk of sliding between the material and the contact means /mandrel during wrapping, thereby further reducing the risk of surface damage.

Advantages of the present invention include:

A more cost efficient wrapping arrangement. A more space efficient wrapping arrangement.

Reduced risk of damage to sensitive strips during coiling/wrapping.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further objects and advantages thereof, may best be understood by referring to the following description taken together with the accompanying drawings, in which: Fig. 1 is a schematic illustration of a basic embodiment of an arrangement according to the invention;

Fig. 2 illustrates another schematic embodiment according to the invention, Fig. 3 illustrates the movement of the embodiment of Fig. 2;

Fig. 4 illustrates another embodiment of an arrangement according to the invention;

Fig. 5 is a perspective view of the embodiment of Fig. 4;

Fig 6 illustrates the movement of the embodiment of Fig. 4; Fig 7a-i illustrate various stages of operation of an embodiment according to the invention.

DETAILED DESCRIPTION

The present invention will be described in the context of wrapping sheets/strips of metal on a mandrel. However, the methods and arrangements are similarly applicable to wrapping of other more or less rigid coilable materials.

Known methods and arrangements for initial wrapping of sheets onto mandrels or coilers comprise so called belt-wrappers. A belt wrapper utilizes a driven belt that is brought into contact with the material to guide it onto a mandrel/ coiler. Thereby the wrapper is in contact with a large surface of the material to be wrapped. This increases the risk of surface damage due to slipping since the potentially damage inducing surface is large. In addition, the machinery for driving the belt is both complex and space consuming.

Therefore, the present invention comprises a wrapper which manages wrapping material with a small contact area between the material and the wrapper, and which is both simple and space consuming in relation to known wrappers. An arrangement according to a basic embodiment of the present invention comprises a forming tool 3 that only maintains contact with the surface of the material at two points 3a, 3b.

Figure 1 illustrates the basic concept of the present invention for the situation with a strip of incoming material 1 with an end extending over a top most point of a mandrel 2. A forming tool 3 comprises two contact units 3a, 3b that are configured to be brought into contact with the surface of the material that extends over the mandrel 2. The contact units 3a, 3b are rotatably attached to the forming tool 3 and are connected via a connection piece Ic to each other, preferably rigidly connected to maintain a constant distance between the contact means 3a, 3b.

During initial wrapping, the forming tool 3 is moved such that the contact units 3a, 3b bring at least a section of the material 1 into contact with the outer surface of the mandrel 2, thereby forming the material 1 around the mandrel 2. Once contact is established, the forming tool 3 is designed to be able to rotate around the mandrel, while maintaining contact between the surface of the material 1 and the mandrel 2.

When the end of the material 1 is wrapped around the mandrel 2 a predetermined length, the mandrel 1 and the forming tool 3 are rotated together or coordinately to further wrap the material 1 around the mandrel 2. The predetermined length can also be expressed as the total angle that the forming tool 1 has moved around the mandrel axis. The coordinated rotation is maintained until the outmost end of the material 1 is secured between the outer surface of the mandrel 2 and the incoming material 1.

Once the end of the material 1 is secured between the incoming material 1 and the mandrel 2, the forming tool 3 is adapted to remain stationary at some predetermined angle until the material 1 has been sufficiently wrapped around the mandrel 2 i.e. three laps. Thereafter the forming tool 3 is removed from contact with the material 1 and returned to a starting position and the mandrel rotation can be increased to coiling speed.

The shape of the forming tool 3 is such as to prevent contact between the forming tool 3 and the material 1 at any other point other than at the two contact units 3a, 3b. According to a specific embodiment the forming tool 3 e.g. the connection piece is curved. In addition, angular shapes are possible.

The contact units 3a, 3b are preferably comprised of rollers with their axis of rotation parallel with the axis of the mandrel 2. Each contact unit 3a, 3b can further comprise a plurality of coaxially arranged rollers.

Further embodiments of arrangements and methods of the invention will be described below.

Accordingly, the arrangement in Figure 2 and Figure 3 illustrates a forming tool 3 with contact rollers 3a. 3b connected to a connection link 3c which is rotatably connected to a second connection link 4 at point A. The second connection link 4 is rotatably connected to a third connection link 5 at point B. Finally, the third connection link 5 is pivotally connected to a base 6 at a point D. The contact rollers 3a, 3b are in contact with the surface of material 1 on a mandrel 2 with central axis at point C.

The location of the respective connection points A, B, D can be varied in order to supply different possible motions of the arrangement.

A schematic of the movement of the points B and A relative to stationary points D and C is illustrated in Figure 3. Accordingly, point B follows a circular path with point D as the axis of rotation. Point A follows a substantially circular path with point C as the axis of rotation. It is evident that until both contact units 3a, 3b have brought the material 1 into contact with the mandrel 2, the point A follows a spiraling path which converges into the above described circular path. Preferably, the first connection link 3c is shaped such that only the contact rollers 3a, 3b are in contact with the material 1 on the mandrel 2. A suitable shape would be angular or curved with a radius of curvature no greater than the mandrel. In addition, the contact units 3a, 3b are arranged such that the linear distance between their contact points with the material is equal to or smaller than the diameter of the mandrel 2.

In addition, the second connection link 4 is preferably curved to enable the arrangement to move freely without colliding with the mandrel 2 during operation.

The embodiments of arrangements according to the invention are illustrated as being mounted standing on a horizontal plane i.e. ground or a floor. However, it is equally possible to mount the arrangement hanging from a ceiling, protruding from a wall or mounted on an inclined plane.

In addition, the arrangements are illustrated with a stationary base. It is however possible, but more complex, to have an arrangement with a non- stationary base.

A further specific embodiment of an arrangement of the invention will be described with reference to Figure 4.

In addition to the previously described details, the embodiment of Figure 4 further includes devices for enabling the various movements of the individual parts. The arrangement optionally includes a breaking arrangement 8 for contacting the surface of the material and for limiting the speed of the incoming material 1 to maintain a set tension in the material 1.

In the illustrated embodiment, the breaking arrangement 8 includes a roller 8 and an actuator unit 9 to enable bringing the breaking arrangement into and out of contact with the surface of the material. The actuator unit 9 includes a pneumatic piston 9 connecting the breaking arrangement 8 and the third connection link 5. However, also other actuator units providing the same operation are possible, i.e. hydraulic pistons, other mechanical or electrical arrangements.

Further, the embodiment of Figure 4 illustrates a pivoting arrangement 7 for enabling the pivoting motion of the third connection link 5. In the illustrated embodiment, the pivoting arrangement 7 includes a hydraulic piston connecting part of the third connection link 5 with the base 6. However, other mechanical or electrical arrangements providing the same motion are possible to implement without departing from the invention.

In this embodiment, the third connection link 5 is illustrated as a substantially straight arm; however, there are no limitations to the overall shape of the link 5. Depending on the application the link 5 can be curved or have some other shape.

Finally, the illustrated embodiment includes a third actuator unit 10 for enabling the forming tool 3 to rotate around as well as in coordination with the rotation of the axis of the mandrel 2. Preferably, the third actuator unit

10 includes multiple pneumatic pistons 10 connecting the third connection link 5 and the forming tool 3. According to another specific embodiment, the third actuator unit 10 comprises two pneumatic pistons. However, in accordance with the previous sections, the same motion of the forming tool 3 can be enabled with other mechanical or electrical arrangements.

Figure 5 illustrates a perspective view of the above-described embodiment, more clearly showing the interrelationship between the various details of the arrangement.

Figure 6 illustrates a specific embodiment of the invention and schematically how the connection points A, B can move relative the stationary points D, C. A schematic of the operation of an arrangement according to the invention will be described with reference to Figures 7a-7c.

Initially, in Figure 7a, the arrangement is positioned in a starting position without contact with the material to be coiled. The material has been fed forward until the end extends past the central axis of the mandrel. As indicated in the Figure 7a, the third connection link 5 is pivoted an angle relative a vertical direction in its starting position. However, the actual magnitude of the angle is not limited to the illustrated; other angles are equally possible depending on the specific application.

Subsequently, in Figure 7b, the arrangement is brought into an operating position. In doing so, the third connection link 5 is pivoted around point D to move the contact rollers 3a, 3b into contact with the surface of the material 1. As can be seen from the illustration the material 1 is formed around the mandrel 2 but not yet brought fully into contact with the outer surface of the mandrel.

In Figure 7c the arrangement has pivoted further and the material is almost into contact with the mandrel by both contact rollers 3a, 3b. In addition, the forming tool 3 has rotated around the mandrel axis by a small angle.

Figure 7d illustrates the further pivoting movement of the third connection link 5 and the rotation of the forming tool 3.

In Figure 7e the forming tool has formed the material around the mandrel and brought the material into contact with the mandrel. In doing so, the forming tool has rotated around the mandrel axis with a preset angle (not shown). Here, the forming tool and the mandrel have initiated their coordinated rotation to feed the material further around the mandrel. To prevent slipping, limiting speed of material and maintaining tension in material the breaking arrangement is optionally activated in Figure 7f. The roller of the breaking arrangement is brought into contact with the material.

The coordinated rotation of the mandrel and the forming tool is continued in

Figures 7g and 7i. Once the forming tool has reached a certain rotational angle around the mandrel axis, to ensure that the end of the material is secured between the incoming material and the mandrel, the forming tool is kept stationary. The mandrel is continuously rotated to wrap the material a predetermined number of laps around the mandrel. Thereby the contact rollers are in rolling contact with the material.

The stationary end position of the arrangement is, according to a specific embodiment, defined by a final preset angle of inclination relative the horizontal direction (or the vertical direction, or some other direction).

However, the angle is not restricted to the depicted angle.

Once a required length of material is wrapped around the mandrel, the forming tool and the breaking arrangement are brought out of contact with the material and goes through the reverse motions to return to the starting position.

Optimally the width of the rollers of the forming tool and the steel sheet are equal i.e. maintaining contact along the entire width of the sheet. However, in a specific embodiment of the present invention the width of the rollers is smaller than the width of the sheet (i.e. w_Sheet=1550 mm, w_roiier=1000). Depending on the thickness of the sheet, the minimum allowed width difference can be different, i.e. a thin sheet is more prone to deform at the edges, thereby preventing efficient wrapping if the tool is too narrow, and vice versa for a thick sheet. This is also dependent on the actual stiffness of the material. Although the invention is described as comprising pneumatic and hydraulic pistons, it is equally possible to use other mechanical or electrical contraptions to serve the same purpose. Other examples are gears, levers, springs etc.

Suitable materials for the outer surface of the mandrel and rollers are polyurethane, plastic, bakelite, steel. In addition, other materials are possible depending on the sensitivity and requirements of the sheet material.

Advantages of the present invention include:

A more cost efficient wrapping arrangement.

A more space efficient wrapping arrangement.

Reduced risk of damage to sensitive strips during coiling/wrapping.

It will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departure from the scope thereof, which is defined by the appended claims.

Claims

1. An arrangement for wrapping an end of a coilable material (1) on a mandrel (2), including forming means (3) comprising first (3a) and second (3b) contact means rotatably connected to said forming means (3) and rigidly connected to each other via first connection means (3 c), said contact means (3a, 3b) are adapted for contacting a surface of said material (1), such that the first and second contact means (3a, 3b) bring at least a section of the material (1) into contact with an outer surface of the mandrel (2); characterized in that: said forming means (3) are further adapted to maintain said contact means (3a, 3b) in contact with said surface and to rotate at least a predetermined angle around the central axis of the mandrel (2) to wrap the end of the material (1) around said outer surface of the mandrel (2).

2. The arrangement according to claim 1, characterized in that said forming means (3) are further adapted to rotate co-ordinately with the rotation of the mandrel (2) in response to said forming means reaching a predetermined angle.

3. The arrangement according to claim 1, characterized in that said first connection means (3c) are rotatably connected to an end of second connecting means (4).

4. The arrangement according to claim 3, characterized in that said first connection means (3c) are curved to prevent any contact between the forming means and the surface of the material other than at the contact means (3a,

3b).

5. The arrangement according to claim 3, characterized in that the connection point of the first connection means (3 c) and the second connection means (4) is adapted to move in a circular path at a distance from and circumventing at least part of the outer surface of the mandrel (2).

6. The arrangement according to claim 3, characterized in that another end of said second connecting means (4) is rotatably connected to an end of third connecting means (5).

7. The arrangement according to claim 3, characterized in that said second connecting means (4) are curved to enable said forming means to rotate around the central axis of the mandrel (2).

8. The arrangement according to claim 6, characterized in that another end of said third connecting means (5) is pivotally attached to a base (6).

9. The arrangement according to claim 8, characterized by pivoting means (7) arranged to enable pivoting of said third connection means (5).

10. The arrangement according to claim 9, characterized in that said pivoting means (7) comprise a hydraulic piston connecting part of the third connection means (5) with the base (6).

11. The arrangement according to claim 1 , characterized in that said first (3a) and second (3b) contact means each comprise at least one roller arranged in parallel with the axis of the mandrel (2).

12. The arrangement according to claim 11, characterized in that each said at least one roller comprises a plurality of coaxially arranged rollers

13. The arrangement according to claim 1, characterized by breaking means (8) adapted for contacting said surface of said material to limit the speed of the material and maintain a predetermined tension in the material.

14. The arrangement according to claim 13, characterized in that said breaking means (8) comprise at least a roller.

15. The arrangement according to claim 13, characterized in that said breaking means (8) comprises first actuator means (9) adapted to enable contact between said breaking means (8) and said surface of the material.

16. The arrangement according to claim 15 and claim 6, characterized in that said first actuator means (9) comprises a pneumatic piston arranged between the breaking means (8) and said third connection means (5).

17. The arrangement according to claim 1, characterized by second actuator means (10) adapted to enable the forming means (3) to rotate in coordination with the rotation of the mandrel (2).

18. The arrangement according to claim 17, characterized in that said second actuator means (10) comprise at least one pneumatic cylinder arranged between said third connecting means (5) and said forming means (3).

19. The arrangement according to claim 1, characterized in that said arrangement is adapted to move from a starting position to a working position to bring said contact means (3a, 3b) of the forming means (3) into contact with the surface of the material (1).

20. The arrangement according to claim 1, characterized in that said forming means (3) are adapted to remain stationary with respect to the mandrel (2) at a predetermined angel until the end of the material is wrapped at least once around the entire circumference of the mandrel (2).

21. The arrangement according to claim 20, characterized in that said forming means (3) and said breaking means (8) are adapted to be removed from said stationary position and returned to said starting position in response to the end of the material being wrapped at least once around the entire circumference of the mandrel.

20. The arrangement according to claim 1 , characterized in that at least one of said contact means (3a, 3b) comprise rubber, plastic, polyurethane, or bakelite.

21. The arrangement according to claim 11, characterized in that said at least one roller comprises rubber, plastic, polyurethane, or bakelite.

22. The arrangement according to claim 1, characterized in that at least the surface of said mandrel comprises rubber, plastic, polyethylene, or bakelite

23. A pivoting roller wrapper comprising an arrangement according to any of the previous claims.

24. A system for wrapping sheet material comprising a pivoting roller wrapper according to claim 23.

25. A method of wrapping an end of a coilable material around a mandrel, comprising bringing first and second contact means of a forming means into contact with a surface of the material to bring at least a section of the material into contact with the outer surface of the mandrel, characterized by: coordinating the rotation of the forming means around the central axis of the mandrel with the rotation of the mandrel, to enable the end of the material to be securely wrapped around the mandrel.