WO2005075326A1

WO2005075326A1 - Arrangement and method for mechanically affecting tension of coilable materials

Info

Publication number: WO2005075326A1
Application number: PCT/SE2005/000086
Authority: WO
Inventors: Sune Bergs; Magnus Sjögren
Original assignee: Bergs Engineering
Priority date: 2004-02-03
Filing date: 2005-01-26
Publication date: 2005-08-18
Also published as: EP1718551A1; SE0400251L; SE528586C2; SE0400251D0

Abstract

An arrangement for mechanically affecting the tension in coilable materials comprises at least one disc (10), the circumference of which at least partly is in contact with the coilable material, said at least one disc (10) comprises an inner disc (11) drivable by a drive shaft (12) and an outer ring (13) arranged substantially around the circumference of the inner disc (11), the outer ring (13) is provided with geometrical structures (14) at an inner portion thereof, an actuator unit (30) arranged on the inner disc (11) is in mechanical engagement with the geometrical structures (14), and is arranged to exert a force on the outer ring (13) in a first rotational direction (15) relative the inner disc (11), and a retaining mechanism (40) arranged at the inner disc (11) in mechanical engagement with the geometrical structures (14), the retaining mechanism (40) is arranged to prevent movement of the outer ring (13) in a second rotational direction (16) opposite the first rotational direction (15), and is also arranged to allow outer ring movement in the first rotational direction (15).

Description

ARRANGEMENT AND METHOD FOR MECHANICALLY AFFECTING TENSION OF COILABLE MATERIALS

TECHNICAL FIELD The present invention relates to equipment for coiling strips or wire in general, and specifically to an arrangement and a method for mechanically affecting the tension of a strip or wire during coiling.

BACKGROUND During cutting of rolled strips to narrow strips followed by winding of the individual narrow strips on mandrels or corresponding arrangements, a problem arises due to the fact that the starting material has a varying tolerance of thickness both lengthwise and widthwise. Rolled strips usually have a greater thickness in the centre of the strip than at the two edges. These variations in thickness in turn cause a difference in diameter build-up on respective mandrel or coiling reel. Consequently, it is difficult to maintain a relatively constant strip tension while driving the mandrels with one common drive shaft since the mandrels would rotate with the same rotational speed. Due to the difference in diameter build up and consequent difference in peripherical speed, the tension or tensile force occurring in the individual strips will differ correspondingly. This difference in tension would in that case disable accurate winding of all strips.

This problem has previously been solved by winding strips on separated coiling discs with a separate drive for each disc, but this has caused relatively high costs and space demanding machinery.

There are similar problems also in other areas, e.g. for web shaped material such as plastic, paper or metal strip, or metal wire. Therefore, efforts in all areas aim to provide a winding arrangement with a plurality of mandrels or coiling discs driven by a common drive shaft. Attempts have been made to solve the problem with differences in diameter build-up for the different mandrels or discs by means of:

-friction couplings between the driveshaft and the mandrels or discs (EP 0863101 ); and

-utilization of one hydraulic pump for each mandrel, where all hydraulic pumps are connected to each other and with suction and pressure sides for leveling of variations in thickness (EP 155 460).

Although these solutions have performed their tasks, all have been accompanied by disadvantages such as high wear and/or costs.

Attempts to utilize various gear mechanisms have also been made, but none of the solutions have been completely satisfactory in relation to cost, simplicity and/or compact design. Consequently, JP 62-51538 describes a differential gear mechanism where planetary gearing arranged side by side on a driveshaft are utilized in order to transfer the driving force equally to the mandrels. In this embodiment a planetary gear is provided for each mandrel, consequently the arrangement inevitably comprises a large number of gears demanding space and results in high cost.

SE 507246 provides a mechanism for winding a plurality of strips with equal tension on a plurality of coiling discs. The mechanism utilizes a complex gear mechanism comprising several gears connecting the various discs to each other and to the drive shaft. The discs are coupled in pairs. Thereby the mechanism is not applicable to single discs, and is limited in the number of discs that can be utilized. Each added pair of discs increases the radial dimensions of the coiling reel. Preferably, the mechanism is utilized for no more than 4 discs. US 2003/0102400 provides a recoiler for recoiling strip-shaped materials, the recoiler comprises a hydraulic device for transmitting a constant torque from the core shaft to the coiling sleeves. The core shaft comprises a truncation that for each coiling sleeve carries a pinion in mechanical contact with the individual rim of the sleeve. Each set of pinion and rim are sealed liquid tight from each other and from the two ends of the shaft in such a manner that the shaft forms a closed hydraulic chamber with the rims. The hydraulic fluid is pumped from one side of the pinion to the other side in response to variations in the tension of the strip. The arrangement demands high precision in fitting of the pinions and the sealing of the hydraulic chambers.

SUMMARY

Problems with prior art have included limitations in number of discs to utilize, difficulties in handling variations in length of individual strips, difficulties to handle sudden changes in strip tension i.e. breaks in strips.

Other problems have been associated with complexity of the mechanical arrangements, contributing to frequent adjustments and operating difficulties.

Also, prior art has involved solutions that are space demanding and thereby limiting in applicability.

Due to the above mentioned problems, an object of the present invention is to provide an improved mechanism for affecting the tension of coilable material during coiling of the material.

Another object is to provide an arrangement for maintaining a constant tension in multiple strips or wires during coiling provided by a common drive shaft.

Yet a further object is to provide a mechanism that is not limited in the number strips that can be simultaneously coiled by one common drive shaft. Another object is to provide an arrangement that can operate even if one or several strips break.

Further, an object of the present invention is to provide an arrangement that is relatively space efficient and provides for easy maintenance.

These and further objects are achieved in accordance with the attached claims.

Briefly, the present invention comprises an arrangement for mechanically affecting the tension of strips or wire of material, where the arrangement comprises at least one disc with an inner disc surrounded by an outer ring. The disc also comprises an actuator unit part of which is in mechanical engagement with geometrical structures of the outer ring and is adapted to exert a force on the outer ring in a first rotational direction. Also, the disc comprises a retaining mechanism arranged in mechanical engagement with the geometrical structures and adapted to prevent the outer ring from moving in a second rotational direction relative the inner disc, opposite of the first rotational direction.

The present invention also comprises a method for mechanically affecting the tension of strips or wire of material, where the method comprises the steps of exerting a force on the outer ring by an actuator unit adapted to move the outer ring in a first rotational direction, moving the outer ring in the first rotational direction, and the step of preventing the outer ring from moving in a second rotational direction.

A preferred embodiment of an arrangement according to the invention comprises a hydraulically operated actuator unit comprising a gear wheel carried by a freewheel hub, and a retaining mechanism comprising a second gear wheel carried by a freewheel hub. BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which: Fig. la is a schematic side view of a line for cutting, transporting and coiling strip shaped material. Fig. lb is a schematic top view of Fig. la. Fig. 2 is a schematic view of an embodiment of an arrangement according to the invention. Fig. 3 is a schematic view of another embodiment according to the invention. Fig. 4 is a schematic view of an embodiment of the invention in a coiler reel. Fig. 5 is a schematic view of an embodiment of the invention in an s-breidel Fig. 6 is a schematic flow diagram of an embodiment of a method according to the invention.

DETAILED DESCRIPTION

The following description mainly describes an arrangement for mechanically affecting the tension of strips of material. It is however equally applicable to any type of coilable material. The term coilable is used as a collective term for any material that is significantly more elongated in a first direction than in a second direction perpendicular to the first direction, and that is possible to coil

Materials that can be described as coilable comprise any one of strips, wire, paper webs, foils. Also, the term does not exclude any geometrical shape of the cross-section of the material.

The present invention will be described in the context of a cutting and coiling strip line for cutting and coiling strips of metal. It is however implied that the invention can be successfully applied to a web cutting and coiling mill for paper or foil. It is likewise applicable to an arrangement for coiling wire.

FIG. 1 illustrates a strip cutting and coiling mill, in which a wide strip of material B is cut and the resulting narrow strips b are threaded through an s-formed holding unit or a so called s-breidel comprising a plurality of drive shafts and finally the strips are coiled on mandrels or coiling reels IOC. The s-breidel comprises two shafts of which at least one is driven, each shaft with a plurality of coiling discs 10A, 10B and is arranged in order to provide a predetermined tension to the separate narrow strips b. The discs 10A, 10B and IOC are possible applications of the present invention.

Basically, the arrangements 10A, 10B and IOC each comprise a plurality of discs arranged on a common shaft. Due to the aforementioned problems with differing thickness of the strips, the discs 10A, 10B, IOC on each shaft are arranged in order to level out any differences in tension between the strips, thereby eliminating problems with slack in the strips.

Referring now to FIG. 2, the present invention basically comprises at least one disc 10, which in turn comprises an inner disc 11 arranged on a drive shaft 12. An outer ring 13 is arranged substantially around the circumference of the inner disc 11, with the central axis of the drive shaft 12 acting as a common rotational axis. An inner portion of the outer ring 13 comprises geometrical structures 14, preferably teeth.

An actuator unit 30 is arranged at the inner disc 11 in mechanical engagement with the geometrical structures 14 of the outer ring 13. The actuator unit 30 has two functions.

One is to transmit torque from the drive shaft 12 to the outer ring 13. The outer ring 13 is thus brought into rotation by the drive shaft 12 with the same rotational speed. The other function is to exert an extra force on the outer ring 13 in a first rotational direction 15 relative the inner disc 11. Thereby the actuator unit 30 enables or forces the outer ring 13 to move in the first rotational direction 15 also relative to the inner disc 11 , whereby the outer ring 13 is displaced by an angle relative the inner disc 11 during the common rotation of the drive shaft 12 and the outer ring 13.

A retaining mechanism 40 is also provided at the inner disc 11. This mechanism 40 is arranged to prevent movement of the outer ring 13 in a second rotational direction 16 opposite the first rotational direction 15 relative the inner disc 11. The retaining mechanism 40 is further arranged to allow for movement of or follow the movement of the outer ring 13 in the first rotational direction 15. Consequently, the retaining mechanism 40 prevents the outer ring 13 to rotate back i.e. in the second rotational direction 16, thereby maintaining the angular displacement that was enabled by the actuator unit 30.

A strip of material B that is affected by the outer surface of the outer ring 13 according to the invention is also illustrated in FIG. 2. During normal operation, the entire arrangement rotates with the drive shaft 12. When the actuator unit 30 causes the outer ring 13 to rotate in the first rotational direction 15 relative the inner disc, a longer section of the strip B will be transported along the outer perimeter of the outer ring 13, as compared to a case where the outer ring 13 does not move relative the inner disc 11. Thereby, the tension in the strip B of material is increased.

It is evident that the location of the actuator unit 30 and the relative movement of the strip of material B, the outer ring 13 and the inner ring 11 can be arranged differently in order to adapt the arrangement to other applications.

During normal operation, i.e. no slack is present; the rotation of the drive shaft 12 creates the tension of the strip, which is in equilibrium with an opposing back tension in the opposite direction from the direction of travel of the strip. The geometrical structures 14 of the outer ring 13 will experience a corresponding force in the first rotational direction at the points of engagement with the retaining mechanism and the actuator unit. A decrease in the strip tension will cause a corresponding decrease in that force, causing the outer ring 13 to lag behind the inner disc 12 in rotation. The extra force that is applied from the actuator unit 30 will act to reestablish the balance between the strip tension and the opposing back tension, and as a consequence reestablish the corresponding force acting on the geometrical structures 14.

FIG. 3 illustrates another embodiment of an arrangement for mechanically affecting the tension of the strip or wire shaped material according to the invention. Details that correspond to details in FIG. 2 have the same reference numbers in FIG. 3. Consequently, the embodiment according to the invention comprises at least one disc 10 comprising an inner disc 11 on a drive shaft 12, said inner disc 11 is surrounded by an outer ring 13. Said outer ring 13 comprises geometrical structures 14 or teeth at an inner portion thereof.

The actuator unit 30 according to FIG. 3 comprises at least one gear wheel 31 that is carried by a freewheel hub 32. The freewheel hub 32 is rotatably attached or arranged at the inner disc 11 at a distance D from the center C of the drive shaft 12. An inner portion of the freewheel hub 32 is rotatably attached to an actuator arm 33, and an outer portion of the freewheel hub 32 is connected to the gear wheel 31 in mechanical engagement with the geometrical structures 14 of the outer ring 13. Further, the attachment is arranged in such a manner that when the actuator arm 33 rotates the inner portion of the freewheel hub 32 according to the first rotational direction 15 relative the inner disc 11, the outer portion of the freewheel hub 32 is forced to rotate simultaneously in the same direction. Thereby, the outer portion of the freewheel hub

32 provides the necessary force to be exerted on the outer ring 13 and moves it in the first rotational direction 15 relative the inner disc 11.

In addition, the actuator unit 30 comprises spring means mounted in order to force the actuator arm 33 to return to its starting position when no force is exerted. One possible manner in which to apply power to the actuator unit 30 is by means of hydraulics. In this case, with reference to FIG. 3, the actuator unit 30 comprises a hydraulic piston 34. The hydraulic piston 34 is mechanically connected to the actuator arm 33 and hydraulically connected to a hydraulic supply system 35. In this embodiment, at least part of the hydraulic supply system 35 is located in the centre C of the drive shaft 12. However, it is implied that the arrangement of the hydraulic supply system 35 can be adapted according to practical implementations for each specific embodiment. The illustrated parts of the hydraulic supply system 35 rotates with the disc 10 during normal operation.

The hydraulic piston 34 is spring-loaded, i.e. when no hydraulic pressure is applied to the actuator unit 30; the hydraulic piston 34 is retracted to its compressed starting position.

The hydraulic supply system 35 is connected to a control entity 36 that preferably controls the supply of hydraulic power intermittently or in a pulse like manner to the system 35. In that case, the actuator arm 33 will return to its starting position in response to the end of such a pulse. Consequently, the hydraulic piston 34 will be compressed until the next such pulse is applied to the hydraulic supply system 35.

The embodiment of the actuator unit 30 is described in the context of a hydraulic supply system. It is however implied that the actuator unit 30 equally can be a pneumatic or electromechanically operated unit. In those cases, the actual detailed arrangement and control of the actuator unit 30 might differ, but the basic function is equal to that of the described hydraulic case.

The retaining mechanism 40 according to FIG. 3 is a second gear wheel 40 carried by a freewheel hub 41 provided at a distance from the drive shaft 12 on the inner disc 11.

It is however attached in a different manner than the first gear wheel 31. An inner portion of the freewheel hub 41 is locked to the inner disc 11 and cannot rotate. Consequently an outer portion of the freewheel hub 41 which is mechanically engaged with the geometrical structures 14 of the outer ring 13, is only able to rotate in the first rotational direction 15 relative the inner disc 11, but prevents the outer ring 13 from rotating in the second rotational direction 16 opposite the first rotational direction 15. Basically, the second gear wheel 41 acts as a one-way gate, allowing the geometrical structures 14 to enter in only one direction, i.e. the first rotational direction 15.

One possible application of the above mentioned arrangement can be utilized in a strip coiling reel. This will be described with reference to FIG. 4.

In FIG. 4 a coiling head or coiling reel or mandrel is illustrated. The mandrel comprises a plurality of coiling discs 10 according to the invention arranged on a common drive shaft 12. The arrangement within each coiling disc 10 is similar to the embodiment of FIG. 3. The pressurization is performed intermittently or in a pulse like manner. Thereby there is a substantially continuous series of consecutive pressure- pulses occurring in the hydraulic supply system. If the strip tension of at least one of the multiple strips decreases, an occurring pulse enables the hydraulic piston to perform a cycle, thereby forcing the first gear wheel to rotate in the first rotational direction and thereby move the outer ring a corresponding rotational angle relative the inner disc. Consequently, a longer piece of that strip is wound or threaded around the coiler disc compared to if the strip tension has been kept constant. Since the pulses are frequent, occurring slack can be adjusted for, at substantially every time instance.

The above is equally applicable to re-coiling and un-coiling. Likewise, the result would be the same if a pneumatically or electromechanically operated actuator unit was utilized.

In addition to the already mentioned and shown details of the embodiment in FIG. 4 a clamping device is required for the coiling arrangement. Each of said plurality of discs 10 has to comprise a clamping device in order to fasten an end of a strip at the outer ring 13. This is however regarded as common knowledge.

Another application for the present invention is in an s-breidel arrangement, referring to FIG. 1, along a strip line. This is also illustrated in FIG. 5.

In FIG. 5 there is illustrated an s-breidel comprising four drive shafts of which two are provided with discs 10 according to the present invention. For simplicity reasons the description will concern one single strip of material, but it is equally adaptable to a plurality of strips. For the latter case, each drive shaft is supplied with a plurality of discs 10. In that case, each drive shaft 10A, 10B is provided with a plurality of discs 10. For the respective drive shafts, the discs 10 are connected to a common actuator power source.

The discs 10A, 10B or plurality of discs 10A, 10B are arranged in a mirror-like manner, i.e. the first disc 10A acts as a brake unit and the second disc 10B acts as a tension unit. Thereby the arrangement enables an increase in the strip tension between the two discs 10 A, 10B regardless of the number of strips b to be affected. The basic function of an s-breidel is regarded as common knowledge and not part of the present invention.

When a plurality of strips are affected by the plurality of discs 10A, 10B it is possible to provide a uniform strip tension for all strips regardless of differences in thickness or length of the strips. Thereby, a plurality of discs 10A or 10B for affecting the tension of a plurality of strips can be driven by a common drive shaft.

Finally, with reference to FIG. 6, a basic outline of an embodiment of the method according to the invention will be given. The method according to the invention will be described for the case of one disc. In a first step S 1 power is applied to the actuator unit. In the case of a hydraulically driven actuator unit the power is applied by means of a pressurization of the hydraulic supply system.

In the next step S2 the applied power is converted into a force that is exerted on the outer ring, more precisely the force is applied to the geometrical structures of the outer ring. If there is a too low tension in the strip, i.e. there is a slack, the exerted force will in a next step S3 cause the outer ring to move in a first rotational direction relative the inner disc. Consequently, the strip will experience a momentarily increase in angular rotation and thereby receive an increase in strip tension.

In the following step S4, when the force is no longer exerted on the outer ring, the retaining mechanism prevents the outer ring from rotating in a second rotational direction opposite the first rotational direction.

Finally, in step S5, the actuator unit is returned to its starting position, where it will remain until power is applied the next time.

For the case of a plurality of discs arranged on a common drive shaft, the power is applied to all connected actuator units simultaneously. Only for those discs that experience a slack will the above described steps be activated.

Preferably, the power to the hydraulic supply system is applied in proportion to the torque that drives the drive shaft. Since the desired tension of the coilable material is provided by a predetermined torque provided by the drive shaft, the applied force from the hydraulic supply system should be able to contribute to the same tension. Basic operation of a coiling or reeling arrangement is not described 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 mechanically affecting tension in coilable materials, said arrangement comprising at least one disc (10), the circumference of each said at least one disc (10) at least partly being in contact with the coilable material, said at least one disc (10) comprising an inner disc (11) drivable by a drive shaft (12) and an outer ring

(13) arranged substantially around the circumference of the inner disc (11), said outer ring (13) being provided with geometrical structures (14) at an inner portion thereof, characterized by

- an actuator unit (30) arranged on the inner disc (11) in mechanical engagement with the geometrical structures (14), said actuator unit (30) being arranged to exert a force on said outer ring (13) in a first rotational direction (15) relative the inner disc (11), and

- a retaining mechanism (40) arranged on the inner disc (11) in mechanical engagement with the geometrical structures (14), said retaining mechanism (40) being arranged to prevent movement of the outer ring (13) in a second rotational direction

(16) opposite the first rotational direction (15), said retaining mechanism (40) being further arranged to allow outer ring movement in the first rotational direction (15).

2. An arrangement according to claim 1, characterized in that said actuator unit (30) is one of a hydraulic, pneumatic or electromechanically operated unit.

3. An arrangement according to claim 1 or 2, characterized in that said actuator unit (30) comprises spring loaded means arranged for resetting the actuator unit (30) when no force is exerted.

4. An arrangement according to any of the claims 1-3, characterized in that said actuator unit (30) comprises a first gear wheel (31) carried by a freewheel hub (32) rotatably arranged on the inner disc (11) at a distance (D) from the drive shaft (12), said first gear wheel (31) being in mechanical engagement with said geometrical structures (14).

5. An arrangement according to claim 4, characterized in that said actuator unit (30) further comprises an arm (33) connected to the freewheel hub (32) of the gear wheel (31) and is arranged to rotate said first gear wheel (31) in said first rotational direction (15) in order to rotate said outer ring (13) in said first rotational direction (15) relative said inner disc (11).

6. An arrangement according to claim 5, characterized in that said actuator unit (30) further comprises a hydraulic piston (34) hydraulically connected to a hydraulic system (35) and mechanically connected to said arm (33).

7. An arrangement according to any of the claims 4-6, characterized in that said retaining mechanism (40) is a second gear wheel (40) carried by a freewheel hub (41) and rotatably arranged at the disc at a distance from the drive shaft (12), said second gear wheel (40) being in mechanical engagement with said geometrical structures (14).

8. An arrangement according to claim 7, characterized in that the freewheel hub (41) of said second gear wheel (40) comprises an inner portion locked to said inner disc (11) and arranged to be non-rotatable around its own axis, and an outer portion arranged to follow said first rotational direction (15) of the outer ring (13) of the disc but arranged to lock the rotation of the outer ring (13) in the second rotational direction (16).

9. An arrangement according to any of the above claims, characterized by a control entity (36) adapted for intermittently controlling power supply to the actuator unit

(30).

10. An arrangement according to any of the claims 1-9, characterized in that said arrangement comprises multiple discs (10) arranged on a common drive shaft (12).

11. An arrangement according to claim 10, characterized in that the actuator unit (30) of each respective disc (10) is connected to a common power source.

12. An arrangement according to any of the claims 1-11, characterized in that the arrangement comprises a first disc (10A) and a second disc (10B) serially arranged on separate shafts (11 A, 1 IB) along a strip line, said two discs (10A, 10B) being arranged to control the tension of the material between the discs (10A, 10B).

13. An arrangement according to claim 12, characterized in that said two discs (10A, 10B) are arranged in a mirror like fashion, whereby said first disc (10A) is adapted to act as a brake unit and said second disc (10B) is adapted to act as a tension unit, thereby enabling an increase in the tension of the material between the discs (10A, 10B).

14. An arrangement according to claim 10 or 11, characterized in that said plurality of discs (10) are arranged as coiling arrangements for coiling coilable material.

15. An arrangement according to claim 14, characterized in that each of said plurality of discs (10) comprises a clamp for an end of a coilable material, arranged to clamp down and fasten the end of the material during coiling.

16. An arrangement according to any of the preceding claims, characterized in that said coilable material comprises one of strips, wire, paper or foil.

17. A method for controlling an arrangement for mechanically affecting tension in coilable materials, said arrangement comprising at least one disc (10) the circumference of each said disc at least partly being in contact with the material, said at least one disc (10) comprising an inner disc (11) and an outer ring (13) adapted substantially around the circumference of the inner disc (11), said outer ring (13) is provided with geometrical structures (14), comprising the step (S0)of rotating said at least one disc (10) characterized by the further steps of : -powering (SI) an actuator unit (30), -exerting(S2) force on the outer ring (13) by the actuator unit (30) in a first rotational direction (15) relative the inner disc (11), said actuator unit (30) being arranged on the disc in mechanical engagement with said geometrical structures (14), said actuator unit (30) is arranged to move said outer ring (13) in the first rotational direction (15), -moving (S3) the outer ring (13) in said first rotational direction (15), if the tension in the coilable material is too low, -preventing (S4) the outer ring (13) from moving in a second rotational direction (16) opposite the first rotational direction (15) and ..-returning (S5) the actuator unit (30) to a starting position

18. A method according to claim 17, characterized by exerting the force intermittently.

19. A method according to claim 17 or 18, characterized by exerting the force by pressurizing a hydraulic system (35).

20. A method according to claims 17-19, characterized by performing said steps of exerting force (S2) in the first rotational direction (15) and preventing movement (S3) in said second rotational direction (16) on each of a plurality of discs (10) arranged on a common drive shaft (12).

21. A method according to claim 20, characterized by applying power to a common power source connected to respective actuator unit (30) of each of said plurality of discs (10).