Arm for an unwinder and unwinder comprising said arm

Abstract

An arm (5; 5A, 5B) of an unwinding machine (1) for unwinding a roll (B) is disclosed. The arm comprises an axial engagement member (11) for engaging the roll (B). The axial engagement member (11) has a shaft (11.3) supported by at least two support bearings (15, 17) mounted on the arm (5; 5A, 5B) so as to rotate about a rotation axis (A-A). A brake (23) is also provided, which is suitable for acting on the shaft (11.3). The brake (23) is at least partially arranged between the two support bearings (15, 17).

Description

Technical Field

[0001] The present invention relates to improvements in machines for handling rolls of wound web material, such as paper and cardboard rolls. More particularly, the present invention discloses improvements in unwinding machines for unwinding rolls and in their components, in particular arms facilitating the unwinding of the rolls. Background Art

[0002] In many industrial fields, there is a need to unwind a roll of web material in order to feed it to a converting line where the web material is transformed into other finished or semi-finished products.

[0003] For example, to produce corrugated board, a continuous sheet of paper is used as a semi-finished product, which is unwound from a roll by an unwinder of a converting line. Some of the sheets are corrugated. Then, the corrugated sheets and non-corrugated sheets are alternately bonded together to form the corrugated board.

[0004] In corrugated board converting lines, paper rolls are unwound by traction. The roll is supported by two axially engaged members, also called "tailstock". The roll is driven in rotation by pulling the paper sheet or web. The tailstock should be equipped with a brake for controlling the unwinding of the paper, thereby avoiding the roll from rotating due to inertia and keeping the web material sufficiently pulled during unwinding.

[0005] The tailstock is usually carried by a pair of arms of the unwinder, the pair of arms having movement towards and away from each other in order to engage the roll with and release it from the tailstock, and to adjust the distance between the tailstocks according to the axial dimensions of the roll. The arms also have a rotational movement around an axis parallel to the axis of the tailstock in order to move the roll during the production steps.

[0006] In the prior art unwinding machines, the arm has a cylindrical base protruding from one side of the arm, at which a support bearing for supporting the shaft of the tailstock is arranged. The shaft extends through the arm and cooperates with a brake, which is carried by the arm on the side opposite to the side from which the tailstock protrudes. The shaft of each tailstock is long and requires a complex support system. Moreover, this known arrangement is complicated, expensive and cumbersome.

[0007] It would therefore be useful to have an unwinder arm for unwinding a roll and an unwinder using pairs of such arms that overcome or mitigate the disadvantages of known unwinders. Summary of the invention

[0008] According to one aspect, an arm of an unwinder for unwinding a roll is disclosed, the arm comprising an axial engagement member for engaging the roll, the axial engagement member also referred to as a "tailstock", the axial engagement member having a shaft supported by at least two support bearings mounted on the arm so as to rotate about a rotation axis. The arm further comprises a brake adapted to act on the shaft of the tailstock.

[0009] In this way, the axial volume of the system consisting of the tailstock and the brake is reduced. The support of the shaft of the tailstock is subjected to less stress and is therefore simpler and more economical in design and smaller in volume.

[0010] The brake is advantageously at least partially arranged between the two support bearings. The brake is preferably accommodated integrally between the support bearings.

[0011] Essentially, the arm for an unwinder thus comprises a tailstock and a brake arranged around the axis of the tailstock, advantageously in the space between two support bearings of the tailstock.

[0012] Because described brake is arranged around the axis of described tailstock, is not aligned with the axis of described tailstock and is not located at one end of described axis, the rear end of the axis of described tailstock (i.e. the end opposite to the cone of described tailstock that engages described roll) is free.Therefore, auxiliary or attached device or equipment can be connected with the rear end of described tailstock.For example, in certain embodiments, motor can be applied to the rear end of described tailstock, for controlling the rotation of described roll.In other embodiments, other useful members, sensors, actuators or parts (such as described arm and described tailstock's attachment or functional unit) can be associated to the rear end of described tailstock.

[0013] In practice, in the distal part of the arm, i.e. in the part opposite to the unwinder structure to which the arm is connected, a housing may be provided. The brake or its components may be housed in said housing, which may be defined by two walls transverse to the axis of the shaft of the tailstock, and the support bearing may be mounted in or associated with said transverse walls.

[0014] The brake may include at least one rotating ring, and preferably a plurality of rotating rings, which are torsionally coupled to the shaft and rotate with the shaft. The rotating ring may be coupled to the shaft of the tailstock, for example, by a slotted coupling. This allows the ring to rigidly rotate with the shaft and simultaneously slide axially along the shaft. The brake may also include a brake disc or a plurality of brake discs, which are interposedly mounted between the rotating rings. The brake disc is carried by the arm so as not to rotate with the shaft of the tailstock and may have movement parallel to the axis of the tailstock.

[0015] The rotating ring and the brake disc are arranged around the axis of the tailstock between the two support bearings. A brake actuator pushes the brake disc and the rotating ring against each other so as to generate a braking torque on the axis of the tailstock. The brake actuator can be arranged around the axis of the tailstock. Advantageously, the brake actuator is also at least partially arranged in the space between the two support bearings of the axis of the tailstock. The brake actuator can be a cylinder-piston actuator, such as a hydraulic actuator.

[0016] The actuator may be a single-acting cylinder-piston actuator and the brake disc may be stressed in the axial direction so as to be spaced relative to the rotating ring by means of a resilient member, such as a helical spring.

[0017] In some embodiments, in order to facilitate the release of the roll from the arm, the arm may include an ejector adapted to eject the roll from the tailstock. The ejector is provided with an actuator and may include a movable plate mounted coaxially with the tailstock and adapted to be moved axially relative to the tailstock by an ejector actuator. The ejector actuator may be housed in the arm, preferably at least partially between two support bearings of the shaft of the tailstock.

[0018] According to another aspect, an unwinder for unwinding a roll of web material is disclosed, the unwinder comprising a support structure and at least one pair of arms or preferably two pairs of arms, each of the arms being configured as described above.

[0019] Further features and embodiments of the arm and the unwinder will be described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be better understood through the following description and the accompanying drawings, which illustrate non-limiting embodiments of the present invention. More specifically, in the accompanying drawings:

[0021] Figure 1 is a side view of an unwinding machine according to the present specification;

[0022] Figure 2 Viewed from the side of the tailstock Figure 1 A side view of an arm of an unwinder;

[0023] Figure 3 Based on Figure 2 A cross-sectional view taken along line III-III;

[0024] Figure 4 Viewed from the side opposite to the tailstock Figure 1 A side view of an arm of an unwinder;

[0025] Figure 5 Based on Figure 4 A cross-sectional view of VV; and

[0026] Figure 6 and Figure 7 Isometric view of the arm of the unwinder. DETAILED DESCRIPTION

[0027] Figure 1 An unwinder 1 is schematically shown and comprises a base or supporting structure 3 to which two pairs of arms 5 are articulated. Figure 1 Only one arm is shown for each pair of arms. Each pair of arms 5 is configured to support a roll B of paper or other web material to be unwound and fed to a converting line not shown. A splicer 7 is provided above the arms 5 to join the trailing edge of a roll supported by one pair of arms to the leading edge of a ready-to-use roll supported by another pair of arms so as to continuously feed the web material N to the converting line. The detailed features of the unwinder 1 and the splicer 7 are not relevant to the present disclosure. Merely by way of example, the splicer 7 may be configured as disclosed in US8011409 and, except for the arms to be described below, the unwinder 1 may be configured as disclosed in EP3464142 or DE102015201180.

[0028] The arms of the unwinder 1 described below can also be used advantageously in unwinders other than those mentioned above.

[0029] The arms 5A, 5B have a rotational movement about a horizontal axis according to arrows f5A and f5B, respectively, allowing the volume B to be raised and lowered. The pair of arms 5A moves synchronously according to arrow f5A. Similarly, the arm 5B moves synchronously according to arrow f5B. Moreover, each arm 5A, 5B has a rotational movement according to an orthogonal Figure 1 The arms of the pair of arms are moved in a translational manner relative to the base 3 in the direction of the plane of the base 3 (ie parallel to the axis of rotation). Due to this movement, each pair of arms can be moved towards and away from each other to engage a roll B with a variable axial dimension.

[0030] Figures 2 to 5 One of the four arms with which the unwinding machine 1 is equipped is shown in detail. The arms 5A, 5B are equal to each other two by two and are symmetrical to each other two by two; therefore, it is sufficient to describe only one of these arms. Figures 2 to 5 In the figure, the number 5 represents the arm.

[0031] The arm 5 comprises a proximal end 5.1, i.e. the end adjacent to the base 3, and a distal end 5.2, i.e. the end spaced from the base 3. The arm 5 carries at its distal end 5.2 a unit comprising an axial engagement member for engaging the roll B, hereinafter referred to as a "tailstock", and auxiliary and accessory elements, members and actuators for the use of the tailstock.

[0032] The tailstock is indicated with the number 11 and has a conical or frustoconical end 11.1 protruding from the arm 5. In the embodiment shown, the tailstock 11 has a radially expandable element 11.2 adjacent to said frustoconical end 11.1. The element 11.2 has a radial expansion and contraction movement in a direction orthogonal to the axis AA of the tailstock 11. The axis AA is parallel to the axis of rotation of the arm 5 relative to the base 3.

[0033] The tailstock 11 further comprises a shaft 11.3 extending towards the inside of a housing 13 arranged in the arm 5. The shaft 11.3 is supported on the arm 5 by two support bearings 15 and 17. In the embodiment shown, the support bearings 15 and 17 are mounted at walls 19, 21 of the arm 5, which are transverse to the tailstock axis AA. The walls 19 and 21 laterally delimit the housing 13 through which the shaft 11.3 of the tailstock 11 extends.

[0034] The tailstock 11 is provided with a brake 23 configured to brake the rotation of the tailstock 11 during operation of the unwinder 1, for example in order to stop the rotation of the roll B or to maintain a desired traction of the web material unwound from the reel. In the embodiment shown, the brake 23 is arranged inside a housing 13 provided in the arm 5 between the transverse walls 19 and 21. In this way, the axial length of the tailstock 11 is reduced and the end of the shaft 11.3 of the tailstock 11 opposite to the frustoconical end 11.1 is free and accessible from the rear.

[0035] In the embodiment shown, the brake 23 comprises a brake member and a brake actuator. The brake member comprises a series of rotating rings 25, which are coupled to the shaft 11.3 of the tailstock 11 and are coaxial with the shaft. The rotating rings 25 are connected to the shaft 11.3 so as to rotate integrally with the shaft, thereby keeping at least partially non-translational relative to the shaft 11.3 in the axial direction (i.e. parallel to the axis AA of the tailstock 11). In some embodiments, the rotating rings 25 are coupled to the shaft 11.3 by a spline profile 11.4 provided on the shaft 11.3. In this way, the rotating rings 25 rotate integrally with the tailstock 11 but can move toward and away from each other according to the double arrows f23.

[0036] A brake disc 27 is interposed between the rotating rings 25, said disc being coupled to the arm 5 so as not to rotate about the axis AA of the tailstock 11. The brake disc 27 may be coupled, for example, to one or more pins 29, which are parallel to the axis AA of the tailstock 11 and rigidly fastened to the arm 5. The brake disc 27 is coaxial with the axis 11.3 of the tailstock 11. A pad 31 made of a high friction material and integral with the rotating ring 25, or preferably with the disc 27, may be interposed between the rotating ring 25 and the brake disc 27.

[0037] By pressing the brake disc 27 and the rotating ring 25 against each other in a direction parallel to the axis AA, a braking torque is generated on the tailstock shaft 11.3. This braking action is given by a brake actuator 33. Advantageously, the brake actuator 33 is a cylinder-piston actuator. Preferably, in order to simplify the supply circuit, the actuator is a pneumatic cylinder-piston actuator.

[0038] In some embodiments, the cylinder-piston actuator 33 has an annular shape and surrounds the axis 11.3 of the tailstock, such as Figure 3 and Figure 5 More specifically, in the embodiment shown, the cylinder-piston actuator 33 has a cylinder 35 forming an annular chamber 36 inside which slides a piston 37, which also has an annular shape and surrounds the shaft 11.3 of the tailstock 11.

[0039] The cylinder-piston actuator 33 is a single-acting actuator. The supply of pressurized fluid inside the annular chamber 36 of the cylinder 35 pushes the annular piston 37 towards the bearing 15 so as to press the rotating ring 25 and the brake disc 27 against each other. When the fluid pressure in the annular chamber 36 decreases, the actuator returns to the rest position by means of an elastic return member, such as a helical spring 39. In the example shown, the helical spring 39 is coaxial with the fixed pin 29.

[0040] In order to have a particularly compact construction, in an advantageous embodiment, the brake actuator 33 is housed in an annular body forming a cylinder 35 and also forming a seat in which a support bearing of the shaft 11.3 of the tailstock 11 is mounted. In the embodiment shown, the annular body forming the cylinder 35 houses the bearing 17. More specifically, in the embodiment shown, the annular body forming the cylinder 35 has a seat 43 at which the bearing 17 is mounted. In some embodiments, the annular body has a mounting flange 45 by means of which it is fastened to the transverse wall 21.

[0041] In order to dissipate the heat generated when the brake 23 is actuated, a ventilation system may be provided, for example comprising or consisting of a fan 47 which circulates air in the housing 13 provided in the arm 5 .

[0042] The described construction is particularly compact and allows a tailstock 11 with a particularly short shaft 11.3. Moreover, the end of the shaft 11.3 opposite the frustoconical end 11.1 of the tailstock 11 is free and accessible from the outside of the arm 5. In the embodiment shown, a cover 49 protects the shaft 11.3 and its rear bearing 17.

[0043] In a possible embodiment, the rear end of the shaft 11.3 can be accessed for connection to a collector of compressed air or other fluid driving the inflatable element 11.2. Moreover, the rear end of the shaft 11.3 can be accessed in order to apply an auxiliary motor to it, if necessary to apply intervening friction or the like. The motor can be used to rotate the tailstock 11 in a controlled manner, for example for unwinding or rewinding the web material of the roll B.

[0044] The brake 23 is housed integrally inside the arm 5 between the transverse walls 19 , 21 delimiting the housing 13 , with a particularly compact construction.

[0045] In some embodiments, an ejector may be associated with the tailstock 11 for facilitating the ejection of the winding core of the roll B, for example for unloading a finished roll or simply for replacing the roll being processed with a different roll for a subsequent order. In some cases, by retracting the inflatable element 11.2 and moving the arms 5 parallel to the axis AA of the tailstock 11 so that the arms are spaced apart from each other, it may happen that the roll B (i.e. its winding rod) remains locked to one of the tailstocks 11. An ejector is used to safely remove the core from the tailstock 11.

[0046] According to the embodiment described herein, the ejector also has a compact construction and is accommodated at least partially in the housing 13 between the transverse walls 19 , 21 .

[0047] In the embodiment shown, the ejector comprises a movable plate 51 coaxial with the tailstock 11 and surrounding the tailstock axis 11.3. When the tailstock 11 is inserted in the end of the roll B, the movable plate 51 is pushed towards the transverse wall 19. In order to facilitate the extraction of the tailstock 11 from the tubular core of the roll B, the movable plate 51 can be pushed against the tubular core (not shown) according to the arrow f51. The pushing according to the arrow f51 is controlled by the ejection actuator.

[0048] In certain embodiments, the ejection actuator includes one or more pneumatic or hydraulic cylinder-piston actuators.

[0049] In the embodiment shown, the ejection actuator comprises two cylinder-piston actuators 53, 55. The two cylinder-piston actuators of the ejection actuator are double-acting actuators and are advantageously arranged in series. This means that a pressurized control fluid can be supplied to a first chamber of one of the cylinder-piston actuators 53, 55, for example to a chamber of the cylinder-piston actuator 55 opposite to the movable plate 51, as schematically indicated by arrow (A). The fluid in the second chamber of the cylinder-piston actuator 55 is discharged (arrow (B)). The second chamber of the cylinder-piston actuator 55 is connected to the chamber of the cylinder-piston actuator 53 opposite to the movable plate 51, where the fluid enters according to arrow (C). The ejection movement causes the fluid to leave the second chamber of the cylinder-piston actuator 53 according to arrow (D). In this way, the supply of pressurized fluid according to arrow (A) causes simultaneous and synchronous actuation of the two actuators 53, 55, thereby pushing the movable plate 51 in the direction of arrow f51. The two pistons of the cylinder-piston actuator 53, 55 are constrained to make the same stroke regardless of any resistance to movement.

[0050] To return the movable plate 51 to the retracted position, the winding rod of roll B can be simply pushed against the top plate 51, thereby moving the arm 5 towards the roll, wherein the tail frame 11 is centered with the axial hole of the winding rod of roll B. The movement of the movable plate 51 in the direction opposite to the arrow f51 causes the working fluid to enter the left chamber (left in the figure) of the actuator 55 according to the direction opposite to the arrow (C), thereby causing the fluid to leave the right chamber of the actuator in the direction opposite to the arrow (B) and enter the left chamber of the actuator 53. The movement of the piston of the actuator 53 discharges the fluid from the right chamber in the direction opposite to the arrow (A).

[0051] In this way, by means of a simple circuit with two pipes connected to the circuit of the working fluid (for example oil), a double push on the movable plate 51 is possible, since the actuators 53 and 55 are arranged in diametrically opposite positions around the axis AA of the shaft 11.3 of the tailstock 11 (i.e. offset by 180°).

Claims

1. An arm (5; 5A, 5B) of an unwinding machine (1) for unwinding a roll (B), the arm comprising: an axial engagement member (11) for engaging the roll (B), having a shaft (11.3) supported by two support bearings (15, 17) mounted on the arms (5; 5A, 5B) so as to rotate about an axis of rotation (AA); as well as a brake (23) adapted to act on said shaft (11.3); wherein the arm (5; 5A, 5B) comprises two opposite walls (19, 21) spaced apart from each other, the two opposite walls extending from the proximal end (5.1) to the distal end (5.2) of the arm; wherein a first support bearing of the support bearings (15, 17) is mounted on a first wall of the two opposite walls (19, 21); wherein a second support bearing of the support bearings (15, 17) is mounted on a second wall of the two opposite walls (19, 21); wherein the axial engagement member (11) protrudes from one of the two opposite walls (19, 21) of the arm; and wherein the brake (23) is arranged inside the arm between the two support bearings (15, 17) and in a space between the two opposite walls (19, 21) of the arm (5; 5A; 5B).

2. The arm (5; 5A, 5B) according to claim 1, characterized in that The two support bearings (15, 17) are included in a space defined between the two opposing walls (19, 21).

3. The arm (5; 5A, 5B) according to claim 1, characterized in that The brake (23) comprises: at least one rotating ring (25) rotatably coupled to the shaft (11.3) and rotating together with the shaft; at least one brake disk (27) coaxial with the shaft (11.3), wherein the rotating ring (25) and the brake disk (27) are movable relative to each other in a direction (f23) parallel to the axis of rotation (AA) of the shaft (11.3); and a brake actuator (33) adapted to press the rotating ring (25) and the brake disc (27) against each other; The at least one brake disc (27) and the at least one rotating ring (25) are arranged between the two support bearings (15, 17).

4. The arm (5; 5A, 5B) according to claim 2, characterized in that The brake (23) comprises: at least one rotating ring (25) rotatably coupled to the shaft (11.3) and rotating together with the shaft; at least one brake disk (27) coaxial with the shaft (11.3), wherein the rotating ring (25) and the brake disk (27) are movable relative to each other in a direction (f23) parallel to the axis of rotation (AA) of the shaft (11.3); and a brake actuator (33) adapted to press the rotating ring (25) and the brake disc (27) against each other; The at least one brake disc (27) and the at least one rotating ring (25) are arranged between the two support bearings (15, 17).

5. The arm (5; 5A, 5B) according to claim 3 or 4, characterized in that The brake actuator (33) is housed inside the arm (5; 5A, 5B).

6. The arm (5; 5A, 5B) according to claim 5, characterized in that The brake actuator (33) is housed between the two support bearings (15, 17).

7. An arm (5; 5A, 5B) according to claim 3 or 4, characterized in that The brake actuator (33) is a cylinder-piston actuator.

8. The arm (5; 5A, 5B) according to claim 7, characterized in that The brake actuator (33) is a single-acting cylinder-piston actuator.

9. The arm (5; 5A, 5B) according to claim 3 or 4, characterized in that The brake actuator (33) has an annular shape and surrounds the shaft (11.3).

10. The arm (5; 5A, 5B) according to any one of claims 1 to 4, comprising an ejector adapted to eject a roll (B) from the axial engagement member (11) and comprising an ejection actuator.

11. The arm (5; 5A, 5B) according to claim 10, characterized in that The ejector comprises a movable plate (51) which is coaxially mounted with the shaft (11.3) of the axial engagement member (11) and is adapted to be controlled by the ejection actuator to move axially relative to the shaft.

12. The arm (5; 5A, 5B) according to claim 10, characterized in that The ejection actuator is housed in the arm (5; 5A, 5B).

13. The arm (5; 5A, 5B) according to claim 12, characterized in that The ejection actuator is at least partially arranged between the two support bearings (15, 17).

14. The arm (5; 5A, 5B) according to claim 10, characterized in that The ejection actuator comprises at least one cylinder-piston actuator (53, 55).

15. The arm (5; 5A, 5B) according to claim 10, characterized in that The ejection actuator comprises two cylinder-piston actuators (53, 55) which are arranged in series with respect to each other.

16. The arm (5; 5A, 5B) according to claim 15, characterized in that The two cylinder-piston actuators are arranged in diametrically opposed positions relative to the axis of rotation (AA) of the shaft (11.3).

17. The arm (5; 5A, 5B) according to any one of claims 1 to 4, characterized in that The brake (23) is accommodated in a housing (13) provided at the end of the arm (5), and wherein the arm comprises a ventilation system (47) for removing heat generated by friction of the brake from the housing.

18. An unwinder (1) for unwinding a roll (B) of web material, comprising a support structure (3) and at least one pair of arms (5A, 5B) according to any one of claims 1-17, the arms being movably supported relative to the support structure (3).

19. The unwinding machine (1) according to claim 18, characterized in that The arms (5A, 5B) have movements towards and away from each other, and movements for translating the rolls engaged by the same arm.

20. The unwinding machine (1) according to claim 18, characterized in that The arms (5A, 5B) have a synchronous rotational movement relative to the bearing structure about an axis parallel to the rotational axis of the respective shaft of the axial engagement member.

21. The unwinding machine (1) according to claim 19, characterized in that The arms (5A, 5B) have a synchronous rotational movement relative to the bearing structure about an axis parallel to the rotational axis of the respective shaft of the axial engagement member.

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