US-20260125171-A1 - FOLDING APPARATUS

US20260125171A1US 20260125171 A1US20260125171 A1US 20260125171A1US-20260125171-A1

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.

Inventors

Marcus KVIST
Dennis ENGMAN
Fredrik LÖÖW
Mikael Nilsson
Stefan NÄSLUND
Henrik HEDSTRÖM

Assignees

VALMET AB

Dates

Publication Date: 20260507
Application Date: 20230901
Priority Date: 20221007

Claims (16)

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

TECHNICAL FIELD The invention relates to the field of folding apparatuses for folding ends of wrapping material around a pulp bale, the wrapping material being arranged around the circumference of the pulp bale and having a length being greater than a length of the pulp bale such that the ends of the wrapping material extend beyond opposite ends of the pulp bale. BACKGROUND Folding apparatuses for folding ends of wrapping material around a pulp bale are known in the art. One example of such a folding apparatus is the Valmet Wrapper Folder, which comprises a plurality of folding arms actuated by hydraulic actuators, which folding arms fold the wrapping material around the edges of the pulp bale. Although such apparatuses provide high performance with low cycle times, a disadvantage is that the folding arms/hydraulic actuators need to be manually adjusted, for example during service of the folding apparatus or when a different bale size is to be used. This is time consuming and poses security problem since the operator needs to enter the security zone of the folding apparatus. SUMMARY An object of the invention is to provide to provide a folding apparatus which at least partly solves or improves on the problems identified above. These and other objects are achieved by the present invention by means of a folding apparatus according to the independent claims. According to a first aspect of the invention, there is provided a folding apparatus for folding ends of wrapping material around a pulp bale when positioned at a bale folding area in said folding apparatus. The wrapping material is arranged around the circumference of the pulp bale and having a length being greater than a length of the pulp bale such that the ends of the wrapping material extend beyond opposite ends of the pulp bale. The folding apparatus comprises at least two folding arms, each comprising a contact element at an end thereof, at least two electric actuators, each being arranged 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 arranged to determine, for each electric actuator, at least one operating parameter comprising a position parameter being correlated to a position of one or more contact element and/or a force parameter correlated or indicative of actuator torque or force and/or a speed parameter correlated or indicative of a speed of rotation or displacement of the electric actuator, wherein said control unit is configured to control at least one electric actuator using said at least one operating parameter. In other words, the folding apparatus comprises a bale folding area, which could also be referred to as a bale folding position, which area or position is where the pulp bale is to be positioned when the folding is to take place. The apparatus further comprises at least two folding arms, preferably arranged at opposite sides of the bale folding area. The folding arms may be displaceable and/or rotatable, for example in the sense that they are rotatable around an axis of rotation or around a ball joint, which axis of rotation or ball joint is optionally displaceable. At least one, or each, of the folding arms comprises a contact element which may be arranged at, or in the vicinity of, an end thereof. The contact elements are adapted to make contact with the wrapping material to fold the wrapping material around an edge of the pulp bale. The apparatus further comprises at least two electric actuators, for example one electric actuator for each folding arm. Each electric actuator is arranged to co-act with one or more of the folding arms such as to displace its contact element. The control unit is arranged in wired or wireless electrical contact with the at least two electric actuators for control thereof. The control unit is arranged to determine, for at least one, or each, electric actuator, at least one operating parameter comprising a position parameter being 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. The control unit is configured to control at least one, or each, electric actuator using the at least one operating parameter, i.e. the control unit uses the at least one operating parameter for feedback control of the electric actuator(s). It is understood that the circumference of the pulp bale refers to a circumference in a plane being substantially vertical to a length direction of the pulp bale. The pulp bale may be described as a rectangular cuboid in shape, where the wrapping material extends around the circumference to cover its long faces (i.e. the longer sides/faces extending in the lengthwise direction of