FOLDING APPARATUS

Abstract

A folding apparatus for folding ends of a wrapping material around a pulp bale, said folding apparatus including: at least two folding arms, each including a contact element at an end thereof; at least two electric actuators, each configured to co-act with a folding arm such as to displace its contact element for making contact with the wrapping material to fold said wrapping material around an edge of the pulp bale; and a control unit configured to: determine, for each electric actuator, at least one operating parameter including a position parameter correlated to a position of one or more contact element and/or a force parameter indicative of actuator torque or force and/or a speed parameter indicative of a speed of rotation or displacement of the electric actuator, and control said at least two electric actuators using said at least one operating parameter.

Claims

1. A folding apparatus for folding ends of a wrapping material around a pulp bale when the pulp bale is positioned at a bale folding area in said folding apparatus, with the wrapping material arranged around the circumference of the pulp bale and having a length greater than a length of the pulp bale such that said ends of the wrapping material extend beyond opposite ends of the pulp bale, said folding apparatus comprising: at least two folding arms each comprising a contact element at an end thereof; at least two electric actuators each configured to co-act with one or more of the folding arms such as to displace its contact element for making contact with the wrapping material to fold said wrapping material around an edge of the pulp bale; and a control unit arranged in electrical contact with said at least two electric actuators, and configured to: determine, for each electric actuator, at least one operating parameter comprising a position parameter correlated to a position of one or more contact element and/or a force parameter indicative of actuator torque or force and/or a speed parameter indicative of a speed of rotation or displacement of the electric actuator, and control said at least two electric actuators using said at least one operating parameter.

2. The folding apparatus according to claim 1, wherein one or more of the at least two electric actuators each comprises an electric motor wherein said control unit is configured to determine said position parameter using data obtained from one or more position sensors connected to the electric motor and/or to a folding arm connected to the electric motor.

3. The folding apparatus according to claim 2, wherein each electric motor is connected to a corresponding folding arm via a gearbox for rotation of the folding arm.

4. The folding apparatus according to claim 2, wherein each electric motor forms part of a mechanical linear actuator connected to a corresponding folding arm.

5. The folding apparatus according to claim 1, wherein: said control unit is configured to determine at least one target displacement parameter for one or more of the electric actuators, said folding apparatus further comprises a Human Machine Interface, HMI, being arranged in communication with said control unit, wherein said HMI is configured to receive user input comprising said at least one target displacement parameter, or user input indicative thereof, and to transmit to the control unit one or more signals indicative of said user input, and said control unit is configured to determine said at least one target displacement parameter using said one or more signals.

6. The folding apparatus according to claim 5, wherein said at least one target displacement parameter comprises at least one of a start position, an end position, a rotation speed, a displacement speed, an actuator torque and an actuator force.

7. The folding apparatus according to claim 1, comprising four of the folding arms arranged symmetrically around the bale folding area, wherein a corresponding electric actuator for each of the four folding arms is configured to co-act therewith such that the contact elements of the four folding arms are, independently of each other, laterally displaceable into the bale folding area to make contact with wrapping material at a corresponding edge of the pulp bale.

8. The folding apparatus according to claim 7, wherein said control unit is configured to, based on at least one operating parameter for the each of the electric actuators co-acting with the four folding arms determine if the pulp bale is misaligned, and if so, control at least one of the electric actuators co-acting with the four folding arms in response thereto.

9. The folding apparatus according to claim 8, wherein the control unit is configured to determine if the pulp bale is misaligned by comparing at least one operating parameter with a corresponding target displacement parameter for each of the electric actuators co-acting with the four folding arms.

10. The folding apparatus according to any claim 1, wherein, among the at least two folding arms, two lower folding arms are arranged symmetrically at opposing sides of the bale folding area, wherein, for each of the two lower folding arms, at least one electric actuator configured to co-act therewith such that the contact element is vertically displaceable towards the bale folding area from below for making contact with wrapping material at a corresponding lower edge of the pulp bale.

11. The folding apparatus according to claim 1, further comprising a rotation device configured to engage with a pulp bale when positioned at said bale folding area to rotate said pulp bale, said rotation device being electrically controlled by said control unit.

12. The folding apparatus according to on claim 10, further comprising: a rotation device configured to engage with a pulp bale when positioned at said bale folding area to rotate said pulp bale, said rotation device being electrically controlled by said control unit, wherein: for each of the two lower folding arms at least one electric actuator is configured to co-act therewith such that the contact element is laterally displaceable, and the control unit is configured to, prior to controlling the rotation device to rotate the pulp bale, control the electric actuators co-acting with the two folding arms to: raise the contact elements of the two folding arms to a vertical level being above the bale folding area, and thereafter, move the contact elements of the two folding arms towards each other for pushing opposite sides of the pulp bale.

13. A method for controlling electric actuators of a folding apparatus for folding ends of wrapping material around a pulp bale, said folding apparatus comprising: at least two folding arms each comprising a contact element at an end thereof, and at least two electric actuators each being configured to co-act with one or more of the folding arms such as to displace its contact element for making contact with the wrapping material to fold said wrapping material around an edge of the pulp bale, the method comprising: determining, for each electric actuator, at least one operating parameter comprising a position parameter correlated to a position of one or more contact element and/or a force parameter indicative of actuator force or torque and/or a position or speed parameter indicative of actuator or folding arm position or speed; and controlling the at least two electric actuators using said at least one operating parameter.

14. A data processing device comprising means for carrying out the method of claim 13.

15. (canceled)

16. A non-transient computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method of claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Above discussed and other aspects of the present invention will now be described in more detail using the appended drawings, which show presently preferred embodiments of the invention, wherein:

[0032] FIG. 1 shows an embodiment of a folding apparatus according to the first aspect of the invention;

[0033] FIG. 2 shows the same embodiment as in FIG. 1 (without the control unit and the HMI) along with a schematic illustration of a pulp bale entering the folding apparatus, and

[0034] FIG. 3 shows a detail view of one side of the folding apparatus in FIGS. 1 and 2.

DETAILED DESCRIPTION

[0035] FIGS. 1-3 show an embodiment of a folding apparatus according to the first aspect of the invention. The folding apparatus 1 is configured for (see FIG. 2) folding ends (for example 2a-d, corresponding ends are present at the opposite end of the pulp bale) of wrapping material 2 around a pulp bale 3 when positioned at the bale folding area 4 in the folding apparatus. As can be seen in FIG. 2, the wrapping material is arranged around the circumference of the pulp bale and has a length being greater than a length of the pulp bale such that ends (2a-d for example) of the wrapping material extend beyond opposite ends (3a for example) of the pulp bale. The folding apparatus comprises folding arms 5a-d, 6a-b, 7a-d, each comprising a contact element 8a-d; 9a; 10a-b at an end thereof.

[0036] Four folding arms 5a-d are arranged symmetrically around the bale folding area 4 at opposing corners thereof. A corresponding electric actuator (each comprising an electric motor 11a-d and a gear box 11a-d) for each of the four folding arms is arranged to rotate the folding arms such that the contact elements 8a-d of the four folding arms are, independently of each other, laterally displaceable into the bale folding area to make contact with wrapping material at a corresponding edge (3 for example, see FIG. 2) of the pulp bale. In other words, each contact element 8a-d makes contact with an end (2a, 2c for example, see FIG. 2) of the wrapping material to fold the end towards/onto an end of the pulp bale (3a for example). The contact elements 8a-d are connected to the respective folding arm 5a-d in a rotatable/pivotable manner around axes of rotation which are parallel to the axes of rotation of the folding arms 5a-d. Springs are arranged to pre-load the contact elements to the shown position. Assuming that the folding apparatus is arranged horizontally (with the bale folding area horizontal), the mentioned axes of rotation are substantially vertical.

[0037] Two lower folding arms 6a-b are arranged symmetrically at opposing sides of the bale folding area 4, wherein, for each of the two lower folding arms, one electric actuator (each comprising an electric motor 12a-b and a gear box 12a-b) is arranged to rotate the folding arms 6a-b such that the contact element (9a for example, arm 6b comprises a corresponding contact element which is not seen in the figures) is vertically displaceable towards the bale folding area from below for making contact with wrapping material at a corresponding lower edge (3for example, see FIG. 2) of the pulp bale. In other words, each contact element (9a for example) makes contact with an end (2d for example) of the wrapping material to fold the end towards/onto an end of the pulp bale (3a for example). The contact elements (9a for example) are connected to the respective folding arm 6a-b in a rotatable/pivotable manner around axes of rotation which are parallel to the axes of rotation of the folding arms 6a-b. Springs are arranged to pre-load the contact elements to the shown position, as can be seen in FIG. 3. Assuming that the folding apparatus is arranged horizontally (with the bale folding area horizontally), the mentioned axes of rotation are substantially horizontal.

[0038] Two sets of upper folding arms 7a-b, 7c-d, are arranged symmetrically at opposing sides of the bale folding area, wherein, for each of the two sets of upper folding arms, one electric actuator (each comprising an electric motor 13 a-b and a gear box 13a-b) is arranged to rotate the folding arms such that the thereto connected contact elements 10a-b are vertically displaceable towards the bale folding area from above for making contact with wrapping material at a corresponding upper edge of the pulp bale. In other words, each contact element (10a, 10b) makes contact with an end (2b for example) of the wrapping material to fold the end towards/onto an end of the pulp bale (3a for example).

[0039] The folding apparatus further comprises a rotation device 17 arranged to engage with a pulp bale 3 when positioned at the bale folding area 4 to rotate said pulp bale.

[0040] The folding apparatus further comprises a conveying arrangement comprising two chains 18a-b arranged to convey the pulp bale from an inlet of the folding apparatus to the bale folding area and further to an outlet of the folding apparatus. In FIG. 2, the bale can be seen at an inlet of the folding apparatus.

[0041] The four folding arms are pairwise, along with one lower folding arm and one upper arm, connected to a sliding device (19a-b for example, see FIG. 3) at opposing sides of the bale folding area. The sliding devices are displaceable towards and away from each other by means of a respective electric actuator (13a-a, 14a-a) being arranged in electrical contact with control unit. As can be seen in FIG. 3, the electric motor 14a is coupled to the sliding device via a rack and pinion arrangement to translate the rotational movement of the motor into linear movement of the sliding device. Thus, when the respective electric actuator of the sliding device is actuated, the axes of rotation of the thereto connected folding arms are displaced (laterally) towards or away from the bale folding area. By actuating the electric actuator of the respective folding arm, it is furthermore rotated for lateral or vertical displacement of its contact element.

[0042] A control unit 15 is arranged in electrical contact with each electric motor 11a-b, 12a-b, 13a-b, 14a-b (indicated by dotted lines to motors on one side of the apparatus). The control unit is arranged to determine, for each electric actuator, three operating parameters: a position parameter (being correlated to a position of the contact elements which is influenced by the actuator), a force parameter indicative of electric motor torque and a speed parameter indicative of a speed of rotation of the electric motor. The control unit is configured to control the electric motors/actuators using the operating parameters.

[0043] The control unit 15 is configured to determine the position and speed parameters using data obtained from position sensors being pulse sensors connected to the shaft of the respective electric motor. The force parameters are determined using the current output to the respective electric motor (which current is known by the control unit).

[0044] The rotation device 17 is pneumatically driven (not shown in the figure), which pneumatic drive is also electrically controlled by the control unit 15.

[0045] The folding apparatus further comprises a Human Machine Interface, HMI, 16 being arranged in electric communication with the control unit. The control unit 15 is configured to determine target displacement parameters for each electric actuator: start and end positions of its contact element, rotation speed and motor torque. The HMI is configured to receive user input indicative of the displacement parameters, and to transmit to the control unit signals indicative of the user input. The control unit is configured to determine the target displacement parameters using the signals. When a pulp bale enters the folding apparatus, it normally enters with its long sides in parallel with the conveying arrangement, as can be seen in FIG. 2. When the pulp bale has been conveyed to the center of the bale folding area 4, having its center at the rotation device 17, an optional aligning procedure may be executed. In this procedure, the control unit 15 orders electric motors 12a-b to raise contact elements of the two lower folding arms 6a-b and the thereto connected contact elements (9a for example) to a vertical level being above the bale folding area, and thereafter control electric motors 14a-b to displace the sliding devices such that contact elements of the two lower folding arms are displaced towards each other for pushing opposite sides of the pulp bale (to align the pulp bale) until target positions are reached, which target positions are determined based on the pulp bale size. The aligning procedure is finalized by controlling the electric motors 12a-b and 14a-b to return to their previous positions. Thereafter, the control unit 15 controls the rotation device 17 to rotate the pulp bale 90 degrees such that the ends of the wrapping materials are directed to the sides. Thereafter, the control unit controls the electric motors 14a, 14b to displace the sliding devices towards the pulp bale, whereafter electric motors 11a-d are activated to displace the contact elements 8a-d laterally, i.e. in a substantially horizontal plane, to make contact with the wrapping material to fold it around the standing edges (3 for example) of the pulp bale. Thereafter, electric motors 12a-b are controlled to displace lower contact elements (9a for example) along a curved path (defined by the length of the folding arms) upwards to make contact with the wrapping material to fold it around respective lower edge (3 for example). When contact elements 8a-d, 9a make contact with the wrapping material, they pivot around their axes of rotation (against the pre-loading of the springs). Thereafter, electric motors 13-ab are controlled to displace upper contact elements 10a, 10b along a curved path downwards to make contact with the wrapping material to fold it around respective upper edge of the pulp bale. Finally, electric motors 14a, b are controlled again to displace the sliding devices away from the pulp bale, and the finished pulp bale with folded wrapping material is conveyed out from the folding apparatus using the conveying arrangement 18a-b.

[0046] While controlling the respective electric motor, the control unit repeatedly determines the operating parameters (position, speed and force) and repeatedly compares the operating parameters with the target displacement parameters and/or limit values such as maximum torque. For instance, when it is determined for an electric actuator that the position parameter is within a predetermined interval from the end position, the control unit stops the movement. Furthermore, the control unit may be configured to determine if the pulp bale is misaligned for example by comparing the position parameter (operating parameter) of contact elements 8a-d with the corresponding end position (a target displacement parameter), and if for instance two of the position parameters are within than a predetermined interval from the corresponding end positions, whereas the other two position parameters are outside the interval, it can be determined that the pulp bale is misaligned. In response to a determination that the pulp bale is misaligned, various control actions are possible. For example, if the force parameter indicative of actuator torque for two diagonally opposing actuator has reached the corresponding actuator torque, while not having reached their corresponding end positions, the control unit can attempt to align the pulp bale by increasing the torque further to these two actuators until the end positions are reached. Alternatively, all actuators can be controlled back to their initial positions, and the pulp rotated back 90 degrees, whereafter the above-mentioned aligning procedure may be executed.

[0047] The description above and the appended drawings are to be considered as non-limiting examples of the invention. The person skilled in the art realizes that several changes and modifications may be made within the scope of the invention. In particular, although a total of four folding arms and contact elements are provided at each side of the folding apparatus, it is foreseen within the scope of the invention that fewer folding arms can be used. For example, the upper and lower folding arms 6a, 10a could be replaced by a single folding arm which axis of rotation is vertically displaceable using an additional electric actuator such as to be able to fold the wrapping material around both the upper and lower edges. Correspondingly, folding arms 5a, 5b could be replaced by a single folding arm. Further, the sliding devices along with the corresponding actuators may be omitted. Further, by choosing start positions of contact elements 8b, 8d which is more spaced apart, the folding apparatus could be arranged to receive the pulp bale at its inlet rotated 90 degrees compared to the position shown in FIG. 2. In such an embodiment, the rotation device may be omitted. Furthermore, the control unit may be configured to determine fewer than the three operating parameters, for instance only the position parameter. Furthermore, the above-described springs arranged to pre-load the contact elements may be replaced with pneumatic cylinders or other devices having corresponding function. Furthermore, although the sliding devices are shown comprising wheels rolling in a track/profile to allow displacement thereof, different arrangements are possible, for example comprising sliding blocks.