SE2250578A1

SE2250578A1 - Automatic trimming apparatus for trimming wire coils and an automatic trimming system including the trimming apparatus

Info

Publication number: SE2250578A1
Application number: SE2250578A
Authority: SE
Inventors: Jens Nylander
Original assignee: Yeminy Inc
Priority date: 2022-05-13
Filing date: 2022-05-13
Publication date: 2023-07-04
Also published as: SE545324C2

Abstract

The present invention relates to an automatic trimming apparatus (1) for trimming vertical wire coils (2) including a plurality of wire loops. The apparatus comprises a base frame (4), a rotational member (6) rotatably connected to the base frame (4) and arranged so that it rotates about a vertical axis (Al), an elevator mechanism (40) connected to the base frame (4) and arranged to raise and lower the rotational member (6) in a vertical direction, a sensor assembly arranged for detecting the end of the wire, and a gripping device (48) adapted to grab a single wire loop from an upper end of the vertical wire coil and to move the wire loop to the rotational member (6), and a cutting device arranged to cut the wire upon receiving a cutting command. The trimming apparatus is adapted to rotate the rotational member in a first direction until the end of the wire is detected, rotate the rotational member in an opposite direction when the end of the wire has been detected, determine when one or more cutting requirements are met during rotation in the second direction, and generate a cutting command to the cutting device when the one or more cutting requirements are met.

Description

Automatic trimming apparatus for trimming wire coils and an automatic trimming system including the trimming apparatus Technical field The present invention relates to an automatic trimming apparatus for trimming wire. Further, the invention relates to an automatic trimming system for trimming wire coils in long rolling mills.

Background A wire coil is made up by a continuous multitude of loop-shaped wire which is created by a loop-forming device located after a final shape rolling device in a wire rod rolling mill. The continuous length ofthe looped wire can be several thousand meters. The loop forming device is followed by a cooling conveyor on which the continuous loops are transported until reaching a vertical collection device into which the loops fall and accumulates into a vertical coil.

An important aspect of the product quality in a long rolling mill that produces wire coils is the final material properties of the wire within the coil. Due to activities in the process of manufacturing the wire, such as the rolling process itself, produces wire with differing properties at the head and tail of each coil. The reduced quality of the tail and head of the wire within the coil require their removal before further processing of coils. Coils that have not been trimmed optimally are one factor of poor-quality coils. Thus, the first and last part ofthe wire in the coil does not meet the quality requirements and must therefore be removed. This process is referred to as coil trimming.

The most common conventional method to remove the tail and the head of a wire coil is to wait until the coil is oriented horizontally. This can be achieved by tilting a vertical pallet to an almost horizontal orientation, or by transferring the coil onto a horizontal C-hook. ln both cases, the coil is presented in a horizontal orientation to an operator. The actual trimming includes largely manual activities whereas an operator identifies and separate the part of the wire rod coil that is to be removed.

To determine this, the operator can count individual rings based on a specific minimum length defined by the specific production conditions for the specific product. The operator can also conduct a basic inspection and remove additional wire if required, as well as removing a sample for analysis. Once the decision to cut at a specific location has been made by the operator, the wire is cut by using some form of cutting device followed by the operator manually lifting and removing the cut part and dispose of it in a designated receptacle. The working environment in this area is prone to injuries and features a generally poor ergonomic working situation.

Manual trimming and sampling, while the coil is still vertical, is rarely ever done because it is almost impossible to perform by human operators and in the rare instance that it is performed, it is very dangerous and exceedingly difficult because of the extreme heat, awkward working position and the poor visibility.

US2019/0291169, EP0992298A2, GB2047597, and KR101568593B1 discloses prior art trimming apparatus. The prior art trimming apparatus comprises means for determining the number of wire |oops to be cut off. A disadvantage with such trimming apparatus is that the sheared positions are determined with poor accuracy leading to a waste of wire.

Summary lt is an aim of the present invention to provide an improved automatic solution to trimming of a wire coil. Another aim is to provide an automatic solution to trimming of a wire coil where the trimming process is performed while the coil remains in a vertical orientation.

According to one aspect of the invention, this aim is achieved by an automatic trimming apparatus as defined in claim 1.

The trimming apparatus comprises: - a base frame, - a rotational member rotatably connected to the base frame so that the rotational member rotates about a vertical axis, - an elevator mechanism connected to the base frame and arranged to raise and lower the rotational member in a vertical direction, - an actuator arranged to rotate the rotational member in two opposite directions, - a gripping device adapted to grab a single wire loop from an upper end of the vertical wire coil and to move the wire loop to the rotational member, and - a control unit for controlling the trimming apparatus, wherein the rotational member is provided with - a space for receiving a wire loop ofthe coil, - a first sensor assembly arranged for sensing the presence of the wire in the space, and - a cutting device arranged to cut the wire upon receiving a cutting command from the control unit, and the control unit is adapted to - control the actuator so that the rotational member is rotated in a first direction until the end ofthe wire is detected based on output from the first sensor assembly, - control the actuator so that the rotational member is rotated in a second direction opposite the first direction when the end of the wire has been detected, - determine when one or more defined cutting requirements are met during rotation in the second direction, and - generate a cutting com mand to the cutting device when the defined cutting requirements are met.

The trimming apparatus according to the invention makes it possible to perform the trimming while the coil remains in a vertical orientation.

The rotational member travels along the wire during rotation of the rotating member, while the wire stands still. Due to the fact that the rotational member rotates about the vertical axis, it is possible for the rotational member to travels along the wire of a vertically aligned coil. lnstead of counting individual rings of the coil as in the prior art, the trimming apparatus according to the invention searches for the end of the wire in the coil while rotating along the wire in one direction, and when the end ofthe wire has been found, the rotational member is rotated in a second direction opposite the first direction until one or more cutting requirements are fulfilled. This makes it possible to find the exact trimming point on the wire with high accuracy. The accuracy in locating the point of trimming guarantee that no excess wire is removed from the coil.

The trimming apparatus can perform the trimming after the continuous mill production. Unlike trimming equipment located within the actual continuous mill, the trimming apparatus according to the invention performs the trimming immediately after the coil has left the continuous mill.

An advantage is that the trimming process can be performed earlier in the process and it can be performed without disturbing the ring-pattern within the coil. By performing the trimming and earlier in the process, the quality-feedback can be provided faster, and any quality deviation can be addressed sooner.

According to an embodiment of the invention, the rotational member is ring shaped and has a central opening aligned with the vertical line.

According to an embodiment of the invention, the rotational member comprises a retainer assembly for retaining wire loops exiting the rotational member during rotation of the rotational member, and the retainer assembly is movable up and down in a vertical direction with respect to the base frame. When the rotational member travels along the wire in the second direction, the part of the wire including the end of the wire exits the rotational member. This wire part is removed from the wire coil when the wire is cut. The retainer assembly prevents the cut wire part from falling down on the coil below the trimming apparatus after it has been cut due to gravity. After the wire has been cut, the retainer assembly is move downwards so that the gripping device can grab the cut wire part and move it to a scrap container.

According to an embodiment of the invention, the retainer assembly comprises a plurality of finger unit adapted to hold the wire loops, and the finger unit are movable up and down in a vertical direction with respect to the base frame. Preferably, the finger units are openable and closable to facilitate the holding and releasing of the wire loops.

According to an embodiment ofthe invention, the rotationa| member is equipped with at least one vision sensor, and the rotationa| member is arranged so that the vision sensor faces downwards to identify a wire loop at an upper end of a vertical coil disposed below the rotationa| member.

According to an embodiment of the invention, the rotationa| member is provided with a wire receiving guide for receiving a wire loop, the wire receiving guide is arranged movable in a vertical direction between an extended position outside the space and a retracted position inside the space, and the gripping device is adapted to move the wire loop to the wire receiving guide. The wire receiving guide receives the wire loop from the gripping device, and moves the wire from the outside of the rotationa| member to the space inside the rotationa| member.

The one or more cutting requirements can be of different types. For example, the distance travelled from the end ofthe wire can be measured while rotating along the wire in the second direction, and one cutting requirement can be that the distance travelled from the end ofthe wire is equal to a predetermined cutting distance.

According to an embodiment of the invention, the trimming apparatus comprises a distance sensorfor sensing a distance travelled along the wire during rotation ofthe rotationa| member in the second direction, and the control unit is adapted to determine the distance travelled along the wire in the second direction based on the output from the distance sensor, and to determine when said one or more cutting requirements are met based on the distance travelled along the wire from the end ofthe wire.

According to an embodiment ofthe invention, the control unit is adapted to generate a cutting command based on the distance travelled along the wire from the end of the wire and a predetermined cutting distance. The distance travelled from the end of the wire is compared to a predetermined cutting distance. For example, the predetermined cutting distance corresponds to a desired cutting length of the wire. This makes it possible to find the exact trimming point on the wire with high accuracy. The accuracy in locating the point oftrimming guarantee that no excess wire is removed from the coil.

A preestablished cutting distance can be defined beforehand based on calculating the optimal trimming position on the wire. A cutting length of the wire is the length of the wire from the end of the wire to the defined optimal trimming position on the wire. The cutting length is a variable parameter and is preferably determined by the user of the trimming apparatus and is normally a function of final rolling velocity of the wire and a specific rolling time which is calculated into a specific distance, or it could be a specific distance based on the physical dimensions of a rolling mill production apparatus. Based on the specific wire diameter, the nominal looped ring diameter, the cutting length plus the physical distance between the sensor assembly and the actual cutting location, the cutting distance can be calculated. The point of trimming will always be exactly as instructed, i.e. according to the predetermined cutting distance.

For example, the one or more cutting requirements can be based on whether one or more physical properties ofthe wire is fulfilled during the rotation ofthe rotating member.

According to an embodiment ofthe invention, the cutting requirements include one or more defined quality requirements for the wire, the rotational member comprises one or more sensor units for sensing one or more physical properties of the wire during the rotation in the second direction, and the control unit is adapted to determine when said one or more cutting requirements are met based on outputs from said one or more sensor units. When the end of the wire has been found, the rotational member is rotated in an opposite direction while measuring one or more physical properties of the wire along the wire. The cutting command is generated in dependence on when the defined quality requirements are met based the outputs from the second sensor assembly. Thus, the point of trimming depends on when the quality requirements are met. The second sensor assembly makes it possible to detect defects in the wire which reduces the quality of the wire. By having one or more sensor units measuring one or more physical properties of the wire and determining when the defined quality requirements are met makes it possible to find an optimal trimming point on the wire with high accuracy. The accuracy in locating the optimal point of trimming guarantee that no excess wire is removed from the coil. This in turn lead to less scrap having to be remelted which reduces cost and environmental influence. Further, it is ensured that wire of pore quality is removed from the end ofthe wire.

The quality requirements are, for example, threshold values for the defined physical properties measured by the second sensor assembly. The quality requirements can be requirements that must be fulfilled according to a customer specification, an official standard, or an internal production manual. The defined measured physical properties of the wire preferably include at least one of surface roughness, surface imperfections, colour, temperature, brightness, and cross-sectional shape of the wire.

According to an embodiment of the invention, said one or more sensor units comprises at least one sensor unit in the group consisting of a surface sensor, a temperature sensor and a colour sensor. The at least one sensor being arranged to perform measurement on the wire of the wire loop during rotation ofthe rotational member.

The distance sensor can be used in addition to the sensor units measuring the physical properties of the wire to avoid that the wire is cut to close to the end. Then, a cutting requirement can be that a minimum distance is travelled from the wire end. The quality ofthe wire can vary along the wire and the quality requirements can be fulfilled at parts close to the end of the wire while they are not fulfilled further away from the end. By measuring the distance travelled along the wire from the end of the wire together with the quality measurements, makes it possible to provide information on where on the wire there are defects that affects the quality ofthe wire. This provides valuable feedback to the rolling mill.

According to another aspect of the invention, this aim is achieved by a trimming system as defined in claim 9.

The trimming system comprises at least one trimming station comprises a trimming apparatus according to the invention, and a coil holder arranged to hold the wire coil in a vertical direction during trimming at the trimming station.

According to an embodiment of the invention, the trimming system comprises a conveyer system arranged to transport the coil holder (66) with the coil to the trimming station so that the wire coil is disposed below the rotational member of the trimming apparatus.

According to an embodiment of the invention, the trimming system comprises a turning mechanism for turning the wire coil between a first vertical position for trimming one end of the wire coil and a second vertical position for trimming the other end of the coil.

According to an embodiment of the invention, said at least one trimming station comprises a first trimming station for trimming one end ofthe wire coil and a second trimming station for trimming the other end of the wire coil, and said conveyer system is arranged to transport the coil holders (66) with the wire coils between the first trimming station, the turning mechanism, and the second trimming station.

Brief description of the drawings The invention will now be explained more closely by the description ofdifferent embodiments of the invention and with reference to the appended figures.

Fig. la shows an example of an automatic trimming apparatus according to the invention in a perspective view.

Fig. lb shows an example of a rotational member of the trimming apparatus in a perspective view seen from below.

Fig. 2 shows an example of a rotational member of the trimming apparatus with a part removed to show the interior ofthe rotational member.

Fig. 3 shows an enlarged part ofthe interior ofthe rotational member.

Fig. 4 illustrates a gripping device of the trimming apparatus picking a wire loop ofthe coil. Fig. 5 illustrates the gripping device placing the wire loop in a receiving guide of the rotational member.

Fig. 6 shows an example of a retainer assembly holding the wire loops during rotation of the rotational member.

Figs. 7a-b illustrate a pinch roller arranged movable with respect to a drive roller so that the wire can be clamped between them.

Fig. 8 shows in a perspective view of a part of the rotational member rotating along the wire loop in a clockwise direction while searching for the end of the wire.

Fig. 9 illustrates in a front view the motions of the rotational member when the trimming apparatus rotates clockwise while unscrambling the wire |oops and searching for the end of the wire.

Fig. 10 shows the rotational member upon detecting the end of the wire.

Fig. 11 shows a cross-section through the rotational member and a cutting device when the rotational member is rotating in a counter-clockwise direction after the end of the wire has been detected.

Fig. 12a shows the cutting device moving to a forward position for receiving the wire when the end ofthe wire has been detected.

Fig.12b shows the cutting device returning to a retracted position after the wire has been cut. Fig. 13 shows in a perspective view from below how the wire is fed into the rotating member. Fig. 14 shows how the wire |oops are co||ected on the retainer assembly during rotation ofthe rotating member.

Fig.15a shows the rotational member in an upper position above a vertical coil ready to begin the trimming process.

Fig.15b shows the rotational member in a lower position closer to the upper end of the coil. Fig.15c shows the trimming device during rotation ofthe rotational member trying to find the end ofthe wire.

Fig. 15d shows the trimming device in a raised position after the trimming has been performed.

Fig.15e shows the trimming device with the retainer assembly holding the removed wire part in a lowered position so that the robot can grip the removed wire part.

Fig. 15f shows the trimming device with the retainer assembly returned to its upper position and the robot is moving the removed wire part to a scrap container.

Fig. 16 shows an example of a trimming system according to the invention including two trimming stations and a turning mechanism for turning the coils.

Figs. 17 - 20 illustrate how the turning mechanism works.

Detailed description Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The trimming apparatus can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

Figure 1a shows an example of an automatic trimming apparatus 1 for trimming vertical wire coils 2 in a perspective view. The trimming apparatus 1 is designed to cut and remove a specific amount of wire from an end of a coil including a plurality of wire |oops. The specific amount of wire to be cut and removed is contingent on physical and geometrical conditions of the wire as well as specific production parameters at the manufacturing location. The specific amount of wire to be cut and removed can be determined beforehand. The length of the specific amount of wire to be cut and removed from the end of the wire is in the following called the desired cutting length. The cutting length can vary due to the type and size of the coil and depends on the type of production machines in the wire rod rolling mill. The cutting length typically varies between 200 mm up to 20 m. The cutting length of the wire can be determined based on a previously established optimal trimming position on the wire.

The trimming apparatus 1 comprises a base frame 4, a rotational member 6 rotatably connected to the base frame 4 so that the rotational member 6 rotates about a vertical line A1, a first actuator 10 arranged to rotate the rotational member 6 in two opposite directions, and a control unit 12 arranged to control the first actuator 10 and accordingly to control the rotational motions of the rotational member 6.

Figure 1b shows an example of a rotational member 6 in a perspective view seen from below. The rotational member 6 is substantially ring shaped. The rotational member 6 is arranged so that it is able to rotate around its center-axis A1. The rotational member 6 is arranged so that its centre-axis is aligned with the vertical line. The direction of the rotation can be either clockwise or counter-clockwise. The interior of the rotational member 6 is described later with reference to figures 2 and 3. The rotational member 6 is adapted to travel along a wire loop 3 of the coil during rotation. ln the illustrated example, the rotational member 6 comprises a retainer assembly 44 for retaining wire loops 3 that exit the rotational member 6 during rotation of the rotational member 6. The retainer assembly 44 is movable up and down relative the rotational member 6 in a vertical direction. ln this example, the retainer assembly 44 comprises a plurality of finger units 45 adapted to hold the wire loops 3. The finger unit 45 are movable up and down in a vertical direction with respect to the base frame 4. ln this example, the retainer assembly 44 comprises four finger unit 45. However, the number of finger unit 45 can be more or less. The finger units 45 are arranged so that they can be open and closed.

The trimming apparatus 1 comprises an elevator mechanism 40 connected to the base frame 4 and arranged to raise and lower the base frame including the rotational member 6 in a vertical direction. ln this example, the elevator mechanism 40 is a floor mounted stand including a support and a movable part movable with respect to the support and attached to the base frame 4. The elevator mechanism 40 comprises an actuator 41 adapted to move the base frame and the rotational member up and down in a vertical direction so that the rotating member can be lowered and raised with respect to a vertical wire coil disposed below the rotational member.The elevator mechanism 40 may, for example, comprise an electric motor for moving the base part up and down along the vertical axis. The elevator mechanism 40 can be arranged in many ways. For example, the elevator mechanism 40 can be a lifting arra ngement attached to a roof.

The rotational member 6 may comprise a wire separation unit adapted to separate the wire |oops in the coi| from each other, and by that make it easy to pick one of the wire |oops from the coi|. Several types of wire separation units are known in the art. ln this example, the wire separation unit comprises two separating rollers 42, as shown in figure 1b. Each separating roller 42 is equipped with a helical shaped groove with a gradually increasing pitch. Each separating roller groove is mirrored to the other separating roller groove and is intended to rotate in opposite directions to each-other. The combined effect of these mirrored gradually increasing grooves rotating in opposite directions is intended to transport the individual wire |oops along the angled separating roller 42 while gradually increasing the space between the individual |oops. lt is also possible to use other types of wire separation units.

The base frame 4 supports the rotational member 6, which is able to rotate around its center- axis A1 by means of the first actuator 10. The first actuator 10 is, for example, an electrical motor equipped with a teethed sprocket wheel. The first actuator 10 is attached to the base frame 4. The torque from the electrical actuator 10 is, for example, applied to a large sprocket connected to rotational member 6 by means of a teethed belt or teethed pinion, thus making the rotational member 6 to rotate. Optionally, the rotational member 6 is equipped with a vision sensor 46 arranged to identify a single wire loop within the plurality of wire |oops.

The rotational member 6 is provided with a wire receiving guide 24 for receiving a wire loop, as shown in figure 1b. The wire receiving guide 24 is arranged movable between an extended position on the outside of the rotational member 6 and a retracted position inside the rotational member 6 by means of an actuator 25, shown in figure 7a. The wire receiving guide 24 is arranged linearly movable in a vertical direction. The wire receiving guide 24 moves the wire from the outside ofthe rotational member to the space 8 inside the rotational member.

The trimming apparatus 1 may further comprise a gripping device 48 adapted to grab the identified single wire loop and to place the single wire loop selected from the plurality of wire |oops into the wire receiving guide 24 when the wire receiving guide is in the extended position on the outside of the rotational member 6. The gripping device 48 is adapted to move the wire loop to the wire receiving guide 24. ln this example, the gripping device 48 is a multi- axis robotic arm equipped with a gripper used to grab and move the identified single wire loop. However, other known types of devices for gripping and moving items can be used.

Figure 2 shows an example of the rotational member 6 with a part removed to show the interior of the rotational member. Figure 3 shows an enlarged part of the interior of the rotational member 6. The interior of the rotational member 6 defines a space 8 for receiving a wire loop of the coi|. The rotational member 6 comprises a support unit 14 arranged in the space 8 for supporting the wire loop 3 in the space 8 when the rotational member 6 is rotated.

The support unit 14 is arranged to move along the wire ofthe coil while the rotational member 6 is rotating. The rotational member 6 and the support unit 14 are moved relative the wire while the rotational member 6 is rotating. The wire loop supported by the support unit stays still during the rotation of the rotational member.

The rotational member 6 comprises a sensor assembly 16 arranged in the space 8 for sensing the presence of a wire in a defined area 17 ofthe space 8. The sensor assembly 16 is disposed at a distance from the support unit 14 so that the end ofthe wire is detected before it reaches the support unit 14. The rotational member may comprise two or more sensor assemblies 16 to allow optimization of the process speed and to achieve redundancy. The distance between the support unit 14 and the defined area 17 is known. The rotational member 6 may further comprise one or more distance sensors 18 for sensing a distance travelled along the wire during the rotation of the rotational member 6.

The rotational member 6 further comprises a cutting device 30 arranged to cut the wire upon receiving a cutting command from the control unit 12. For example, the cutting device 30 comprises an electro-hydraulic cutter. The cutting device 30 is attached to the rotational member 6. The cutting device 30 is disposed a distance from the support unit 14. The cutting device 30 is also disposed a distance from defined area 17.

The control unit 12 comprises processing circuitry for processing sensor data received from the sensor assembly 16 and optionally from the distance sensor 18 and for sending instructions to the components it is controlling, such as actuators 10, 21, 23, 25 and the cutting device 30. Communication between the control unit 12 and the sensors 16, 18 and the components it is controlling, may com prise wired or wireless communication. The control unit 12 may comprise software code portions, such as a computer program, comprising instructions for carrying out steps of the invention, and hardware, such as a processor, memory and input/output devices, for carrying out the instructions of the software code portions. ln this example, the control unit 12 is adapted to generate a cutting command to the cutting device 30 based on a predetermined cutting distance. The predetermined cutting distance can be determined beforehand based on a predetermined optimal trimming position on the wire. A cutting length of the wire is the length of the wire from the end of the wire to the predetermined optimal trimming position on the wire. The cutting length is a variable parameter and can be determined by the user of the trimming apparatus. The cutting distance can be calculated based on the desired cutting length, the specific wire diameter, the nominal wire loop diameter and the position ofthe support unit 14, the position ofthe sensor assembly 16, and the position ofthe cutting device 30. The control unit 12 may comprise a data storage for storing the predetermined cutting distance. The control unit can be adapted to receive the predetermined cutting distance and to store it in the data storage. Alternatively, the control 11 unit can be adapted to receive the desired cutting length and to calculate the cutting distance based on the cutting length.

The control unit 12 is adapted to receive outputs from the sensor assembly 16 and the distance sensor 18. The control unit 12 is adapted to detect the end of the wire 3a based on the output from the wire sensor assembly 16, to control the first actuator 10 so that the rotational member 6 is rotated in a first direction until the end of the wire is detected, to control the first actuator 10 so that the rotational member 6 is rotated in a second direction opposite the first direction when the end of the wire has been detected, to determine the distance travelled along the wire when the rotational member is rotated in the second direction based on the output from the distance sensor 18, and to generate a cutting command based on the distance travelled along the wire from the end of the wire and the predetermined cutting distance. The control unit 12 is adapted to compare the distance travelled in the second direction with the predetermined cutting distance, and to generate the cutting command when the distance travelled along the wire in the second direction corresponds to the predetermined cutting distance.

The support unit 14 is arranged to move along the wire while the rotational member 6 is rotating. The rotational member 6 and the support unit 14 are moving relative the wire. The support unit 14 comprises a drive roller 20 and a pinch roller 22 rotatably connected to the rotational member 6. The trimming apparatus comprises a second actuator 21 arranged to rotate the drive roller 20 in two opposite directions, shown in figure 8. The second actuator 21 is, for example, an electric motor. The pinch roller 22 is arranged linearly movable with respect to the drive roller 20 in a radial direction of the rotational member, as shown in figure 7a-b, to allow the wire loop to be clamped between the drive roller 20 and the pinch roller 22, as shown in figure 9. Thus, the position of the wire in a radial direction of the rotational member is fixed while the rotational member 6 is rotating with respect to the wire. The rotational member 6 comprises an actuator 23 arranged to move the pinch roller 22 towards and away from the drive roller 20.

The wire receiving guide 24 has a recess 26 for receiving the pinch roller 22 in the retracted position. The wire receiving guide 24 is arranged linearly movable with respect to the pinch roller 22 in an axial direction of the rotational member 6. The pinch roller 22 is arranged linearly movable with respect to the recess 26 in the radial direction ofthe rotational member 6. Due to the recess 26, the pinch roller is allowed to move towards and away from the drive roller 20 when the wire receiving guide 24 is in the retracted position. The receiving guide 24 has an exit 24a for the wire arranged in one end.

The drive roller 20 and the pinch roller 22 are arranged so that they rotate in opposite directions with respect to each other when the wire is clamped between them, and the rotational member 6 is rotated in any ofthe first and the second directions as shown in figures 10 and 11. Thus, the drive roller 20 and the pinch roller 22 are rolled along the wire 3 while 12 the rotational member 6 is rotated. Thus, unintentional damage of the wire is avoided when the support unit 14 clamps the wire during rotation of the rotational member 6. The friction between the wire and the drive roller 20 and the pinch roller 22 is reduced due to the fact that the drive roller 20 and the pinch roller 22 rotate along the wire instead of sliding along the w|re.

The control unit 12 is adapted to control the first and second actuators 10, 21 so that the drive roller 20 and the rotational member 6 are rotated in the same direction in a synchronized manner to allow the drive roller 20 and the pinch roller 22 to roll on the wire while the rotating member 6 is rotated relative the wire. ln this example, the pinch roller 22 has no actuator. The pinch roller 22 is rotated due to the friction against the wire and the movements of the rotating member 6.

The rotational member 6 is arranged rotatable with respect to the base frame 4 about a first rotational axis coinciding with the central axis A1. The drive roller 20 is arranged rotatable with respect to a second rotational axis in parallel with the central axis A1, and the pinch roller 22 is arranged rotatable with respect to a third rotational axis in parallel with the central axis A1, and the first, second, and third rotational axes are in parallel.

The control unit 12 is adapted to control the first and second actuators 10, 21 so that the rotational member 6 and the drive roller 20 are rotated in the first direction in a synchronized manner until the end of the wire 3a has been detected, as shown in figure 9 and 10, and to control the first and second actuators 10, 21 so that the rotational member 6 and the drive roller 20 are rotated in the second direction after the end of the wire 3a has been detected, as shown in figure 11. The control unit 12 is adapted to control the first and second actuators 10, 21 so that the rotational member 6 and the drive roller 20 are rotated in the second direction until the distance travelled along the wire corresponds to the predetermined cutting distance. The control unit 12 is adapted to stop the rotational movements of the rotational member 6 and the drive roller 20 and to generate the cutting command when the support unit 14 has travelled the predetermined cutting distance along the wire in the second direction.

The sensor assembly 16 is arranged to detect when the end of the wire 3a is present in the defined area 17. The sensor assembly 16 can be arranged for sensing the presence of the wire 3 in the defined area 17 of the space 8, as shown in figure 9, and also to detect when the wire 3 is no longer present in the defined area 17, as shown in figure 10. The sensor assembly 16 is used to detect the end of the wire 3a. For example, the output from the sensor assembly 16 stays 1 as long as the wire 3 is sensed in the defined area 17, and the output from the sensor assembly 16 is switched to 0 when the wire is no longer present in the defined area. Thus, it is possible for the control unit 12 to detect when the end of the wire 3a has passed through the defined area 17. Different types of sensor can be uses to detect the end of the wire. For example, the sensor assembly 16 may comprise an optical sensor adapted to detect when the 13 end of the wire is present in the defined area 17. ln this example, the sensor assembly comprises a sensor roller 16a and an inductive sensor 16b arrange to detect when the sensor roller 16 is moved downwards, as shown in figure 10. The sensor roller 16a is spring tensioned so that the sensor roller is biased towards the wire. The sensor roller 16a is arranged so that it rolls on the wire 3 as long as the wire is present in the area 17, as shown in figure 9. When the end of the wire 3a is present in the area 17, the sensor roller 16a rolls off the wire and is moved a short distance towards the centre of the rotating member due to the spring force acting on the sensor roller 16, as shown in figure 10. The inductive sensor 16b is arranged to detect the movement of the sensor roller 16a. This type of sensor assembly is known in the art.

The distance sensor 18 can be arranged in different ways. For example, the distance sensor 18 can be arranged to detect the distance travelled by the support unit 14 along the wire. ln one example, the distance sensor 18 can be an electrical pulse-encoder connected to the driven roller 20 and arranged to detect the rotational motions of the drive roller 20. Thus, the actual length of wire passing through the support unit 14 can be measured. The distance sensor 18 can, for example, be arranged to detect the number of revolutions of a drive axis of the motor 21 actuating the drive roller 20. The control unit 12 receives outputs from the distance sensor 18 and determines the distance travelled along the wire in the second direction based on the received output from the sensor 18. ln this example, the distance sensor 18 senses the distance travelled by the drive roller 20 along the wire. Other examples could be to connect a distance sensor of electrical pulse-encoder type, to the sensor roller 16a or to the pinch roller 22. ln these examples, the actual length of wire passing through the sensor assembly can be measured on non-powered rotating members.

Figures 4 and 5 illustrates when the trimming apparatus receives a single wire loop 3 of the wire coil.

Figure 4 illustrates the gripping device 48 of the trimming apparatus picking a wire loop 3 of an upper end of the coil 2. The rotating member 6 has been moved close to the upper end of the coil 3 so that the rotating member 6 faces the upper end ofthe coil 3. The receiving guide 24 is in the extended position on the outside of the rotational member 6. The fingers 45 ofthe retainer assembly 44 are closed.

Figure 5 illustrates how the gripping device 48 places the wire loop 3 in the receiving guide 24 of the rotational member. The coil 2 has the wire loops 3 separated at an end facing the trimming apparatus 1. The receiving guide 24 moves the wire loop 3 to the space 8 inside the rotating member 6. Upon receiving the single wire loop 3 in wire receiving guide 24, the control unit 12 activates the actuator 25 to retract the wire receiving guide 24 to its retracted position. The fingers 45 ofthe retainer assembly 44 are now opened to let the wire loops pass them and to be ready to hold the wire loops.

Figure 6 shows the fingers 45 of the retainer assembly 44 holding the wire loops during rotation ofthe rotational member. The fingers 45 of the retainer assembly 44 are now closed. 14 The receiving guide 24 is now in the retracted position on the inside ofthe rotational member 6.

Figures 7a-b shows the interior of the rotational member 6 in a front view. The pinch roller 22 is arranged movable with respect to the drive roller 20 so that the wire loop 3 can be clamped between them. The control unit 12 activated the actuator 23 to press the pinch roller 22 against a part of the looped wire 3 within the wire receiving guide 24 and against the drive roller 20. A different actuator (not shown) is activated to press the sensor roller 16a against another part ofthe wire within the wire receiving guide 24, as shown in figure 9.

Figure 8 shows a part of the rotational member 6 rotating along the wire loop 3 to find the end of the wire 3a. The rotational member 6 begins to rotate around its centre axis A1 by means of the electrical motor 10 attached to the base frame 4. The direction of the rotation can be either clockwise or counter-clockwise, depending on the specific production parameters when producing the coiled loops. While the rotational member 6 is rotating in one direction, the driven roller 20, powered by the actuator 21, is arranged to rotate along the looped wire in the same rotational direction in a synchronized manner between the two rotating motions, resulting in axially un-scrambling of the different wire loops while not changing the actual geometry of each individual loop in the radial direction while simultaneously organizing the wire loops in a successive order, one after another starting with the last wire loop in the plurality of wire loops closest to the rotational part 6 of the trimming apparatus. These rotating motions continues until the sensor roller 16a detects the end 3a of the last wire loop in the coil and activates the inductive sensor 16b.

Figure 9 illustrates the motions ofthe rotational member 6, the drive roller 20, the pinch roller 22, and the sensor roller 16a when the trimming apparatus is searching for the end of the wire. The rotational member 6 is rotated in a first direction. As seen from the figure, the drive roller 20 and the pinch roller 22 rotate in opposite directions, and the rotational member 6, the drive roller 20, and the sensor roller 16a rotate in the same directions. The drive roller 20, the pinch roller 22, and the sensor roller 16a are in physical contact with the wire 3. The drive roller 20 and the pinch roller 22 are moving along the wire in the first direction and towards the end ofthe wire 3a.

Figure 10 shows interior of the rotational member 6 upon detecting the end of the wire 3a. The sensor roller 16a is moved downwards due to the spring tension when the sensor roller 16a has passed the end of the wire, and the inductive sensor 16b detects the change of position of the sensor roller 16a. The control unit 12 receives information on that the end of the wire has been detected from the inductive sensor 16b. The control unit 12 send orders to the first and second actuators 10, 21 to change the direction of the rotation of the rotational member 6 and the drive roller 20 upon receiving the information that the end of the wire has been detected.

Figure 11 illustrates the motions of the rotational member 6, the drive roller 20, the pinch roller 22, and the sensor roller 16a after the end of the wire 3a has been detected. The rotational member 6 and the drive roller 20 are now rotated in the second direction, opposite the first direction. The drive roller 20 and the pinch roller 22 are moving along the wire in the second direction and away from the end of the wire 3a. During the rotation of the rotational member 6 in the second direction, the distance sensor 18 measures the distance travelled along the wire. The rotation ofthe rotational member 6 continues until the distance travelled along the wire in the second direction is equal to the predetermined cutting distance. The rotational member 6 can be rotated several turns until the distance travelled along the wire is equal to the predetermined cutting distance. ln an alternative embodiment of the invention, the rotational member 6 comprises one or more sensor units 38 for sensing one or more physical properties of the wire during the rotation in the second direction, and the control unit is adapted to determine when the one or more cutting requirements are met based on outputs from said one or more sensor units. The sensor units 38 comprise at least one sensor arranged to perform surface measurements on the wire loop, or/and a sensor arranged to perform temperature measurements on the wire loop, or/and a sensor assembly arranged to perform colour detection on the wire loop.

Figure 11 shows a cross-section through the rotational member 6 including an example of a cutting device 30. The cutting device 30 comprises a cutter 29 provided with a movable steel cutter 36. ln this example, the cutter 29 is an electro-hydraulic cutter 29. However, other types of cutters can be used. The cutting device 30 may comprise a guide member 31 for guiding the wire towards the steel cutter 36. ln the illustrated example, the guide member 31 is attached to the cutter 29. ln an alternative embodiment, the guide member 31 can be a separated part movable with respect to the cutting device 30. The guide member 31 has an accommodation 32 with an inlet 34 arranged to receive the end of the wire 3a when the rotational member 6 is rotated in the second direction. ln the illustrated example, the cutting device 30 is linearly movable between a retracted position and a forward position, as shown in figures 12a-b. ln this example, the cutting device 30 is movable in an axial direction of the rotational member 6. The steel cutter 36 is cutting the wire while in the forward position and is retracted after completed cutting process. ln its retracted location it is positioned and ready for the next trimming operation. The rotational member 6 comprises an actuator 37 for moving the cutting device 30. The control unit 12 is controlling the actuator 37 and accordingly the motions ofthe cutting device 30. ln an alternative embodiment, the cutting device 30 can be fixedly attached to the rotational member 6 and accordingly not movable with respect the rotational member, and the guide member 31 is movable with respect to the cutting device 30. This is advantageous if the cutting device is heavy.

The cutting device 30 is arranged to move the steel cutter 36 upon receiving the cutting command so that the wire guided by the accommodation 32 is cut. The cutting device 30 may comprises an actuator (not shown) for moving the steel cutter so that it cuts the wire. For 16 example, the actuator is an electrical motor driving a small hydraulic pump. The hydraulic fluid in the pump is pressing against the steel cutter 36, forcing it forward to cut the wire. The actuator for moving the steel cutter 36 is controlled by the control unit 12, and the actuator is activated upon receiving the cutting command.

Figure 12a shows the cutting device 30 moving to the forward position when the end of the wire has been detected. Figure 12b shows the cutting device 30 returning to the retracted position after the wire has been cut.

When the end of the wire has been detected, the control unit 12 sends an order to the actuator 37 to move the cutting device 30 from its retracted position to its forward position, as shown in figure 12a, so that the inlet 34 ofthe guide member 31 is aligned with the exit 24a of the receiving guide 24. While moving in a synchronized manner, the rotational member 6 and the drive roller 20 now start to rotate in the second direction, moving the end ofthe wire 3a into the accommodation 32 of the guide member 31, through the accommodation 32, through the cutter 29 and further into a segmented discard wire guide (not shown).

During the rotation of the rotational member 6 in the second direction, the distance sensor 18 measures the actual length of wire passing through support unit 14. This movement continues until the distance travelled along the wire in the second direction is equal to the predetermined cutting distance. This means that a specific length of wire has been collected in the discard wire guide. At this point all rotating movements stop and the cutter 29 make a cut, separating the wire accumulated in the discard wire guide from the wire on the opposite side of the cutting device 30, which now is the new front-end of the last wire loop. After the wire has been cut, while moving in a synchronized manner, the rotational member 6 and the drive roller 20 now start to rotate in the opposite direction from the previous step until the new front-end of the remaining plurality of circular wire loops exits the receiving guide completely. The trimming apparatus can now move away from the plurality of circular wire loops to a retracted discard position by means of an electrical motor acting with a teethed pinion against a teethed rack.

Figure 13 shows the trimming apparatus 1 and a coil 2 comprising a wire wound into a plurality of circular wire loops 3. A wire loop 3 consists of a circular part of the wire. The wire loops 3 at the upper end of the coil are separated. The wire is entered into the rotating member 6 by means of the receiving guide 24. The wire entering into rotating member is denoted 50. The finger units 45 collects the wire exiting from the rotating member 6 and separates the wire exiting from the rotating member 6 from the wire 50 entering the rotating member 6.

Figure 14 shows how the wire loops 3 are collected on the finger units 45 of the retainer assembly during rotation of the rotating member. The incoming wire 50 enters the rotating member 6 and the exiting wire 52 leaves the rotating member 6. The finger units 45 collects the exiting wire 52 leaving the rotating member 6 during the rotation ofthe rotating member 17 in the second direction. The exiting wire 52 is the scrap wire that is to be removed from the coil. The finger units 45 move up and down in a vertical direction and the finger units 45 open and close depending on the process steps. The finger units 45 do not rotate. ln the following, an example of the steps of the trimming process will be explained with reference to the figures 15a - 15f.

The rotational member 5 is in an upper position above a vertical coil 2 ready to begin the trimming process, as shown in figure 15a. The finger units 45 straighten while the vision system identifies an appropriate wire loop 3. The rotating member 6 is lowered to a lower position closer to the upper end of the coil, as shown in figure 15b. The gripping device 48 picks the selected wire loop and moves it to the receiving guide 24, as shown in figures 4 - 6. The gripping device 48 places the selected wire loop in the receiving guide 24. The receiving guide 24 moves to its retracted position inside the rotating member 6. The rotating member 6 rotates clockwise to locate the end of the wire, as shown in figure 15c. The finger units 45 close, and the rotating member 6 rotates counter clockwise while measuring the length to be trimmed. The scrap wire to be removed is automatically ejected and placed in the closed scrap fingers. The scrap wire is cut by the cutting device and separated from the rest of the coil. The device is raised so that the trimmed coil can be transported further, as shown in figure 15d. The finger units are lowered, as shown in figure 15e. The scrap wire loops are gripped by the gripping device 48. The finger units return to the start position while the gripping device 48 moves the scrap wire loops towards a scrap container, as shown in figure 15f. The rotating member 6 is lowered further and the gripping device 48 places the scrap wire lops in the container.

Figure 16 shows an example of a trimming system 60 according to the invention including a first trimming station 62 and a second trimming station 64 and a turning mechanism 70 for turning the coils. The first trimming station 62 is used for trimming one end of the wire coil 2 and the second trimming station 64 is used for trimming the other end of the wire coil. Each ofthe trimming stations 62, 64 comprises a trimming apparatus 1. The turning mechanism 70 is used for turning the wire coils 2 between a first vertical position for trimming one end of the wire coil and a second vertical position for trimming the other end ofthe coil. The trimming system 60 further comprises a plurality of coil holders 66 arranged to hold the wire coils in a vertical direction during trimming at the trimming station. The wire coil 2 is disposed below the rotational member 6 of the trimming apparatus 1 at the trimming stations. The trimming system 60 comprises a conveyer system 68 arranged to transport the coil holders 66 with the wire coils between the first trimming station 62, the turning mechanism 70, and the second trimming station 64. ln alternative embodiments, the trimming system 60 may include one trimming station or more than two trimming stations. 18 Figures 16 - 20 illustrate an example of how a turning mechanism can work. Figure 16 shows a tail-end trimmed wire coil 2a which has been transported from the first trimming station 62 to one end of the turning mechanism 70. At the same time, an empty pallet is waiting at the opposite side of the turning mechanism 70. The turning mechanism 70 comprises two tilt stations 71, 72 and a transfer trolley 73 for moving the coil holder 66 with the ti|ted wire coil between the tilt stations 71, 72. Figure 17 shows the tilt transfer stations 71, 72 in ti|ted positions. The wire coil 2a is rotated to a horizontal position. The transfer trolley 73 lifts the wire coil 2a from the ti|ted pallet and supports the ends so that the wire coil does not collapse. The transfer trolley 73 transports the wire coil 2a to an empty pallet on the opposite side, as shown in figure 18 and 19. The transfer trolley 73 places the wire coil 2a on the empty pallet at the same time as it releases the grip on the ends and lowers so that the wire coil is carried by the ti|ted pallet. Both pallets rotate up to the vertical position while the transfer trolley 73 returns to the start position. The receiving palette now has a wire coil that is "inverted" where the nose-end points up and the tail-end points down, as shown in figure 20. After the inversion is completed, the wire coil is transported to the second trimming station 64 which trims the "nose-end" in the same way as the first trimming station 62 trimmed the "tail-end".

By arranging the trimming apparatus in a vertical orientation, the same activities can be performed on a wire coil placed on a vertical pallet.

The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. For example, the elevator mechanism can be arranged in many different ways, the number of finger units of the retainer assembly may vary, and the apparatus may comprise more than one a distance sensor.

Claims

1. Automatic trimming apparatus (1) for trimming vertical wire coils, characterized in that the trimming apparatus comprises: - a base frame (4), - a rotational member (6) rotatably connected to the base frame (4), wherein the rotational member (6) is arranged so that it rotates about a vertical axis (A1), - an elevator mechanism (40) connected to the base frame (4) and arranged to raise and lower the rotational member (6) in a vertical direction, - an actuator (10) arranged to rotate the rotational member (6) in two opposite directions, - a gripping device (48) adapted to grab a single wire loop from an upper end of the vertical wire coil and to move the wire loop to the rotational member (6), and - a control unit (12) for controlling the trimming apparatus, wherein the rotational member (6) is provided with - a space (8) for receiving the wire loop (3), - a sensor assembly (16) arranged for sensing the presence of the wire in the space, and - a cutting device (30) arra nged to cut the wire upon receiving a cutting com ma nd from the control unit (12), and the control unit (12) is adapted to - control the actuator (10) so that the rotational member (6) is rotated in a first direction until the end of the wire is detected based on output from the first sensor assembly, - control the actuator (10) so that the rotational member (6) is rotated in a second direction opposite the first direction when the end of the wire has been detected, - determine when one or more defined cutting requirements are met during rotation in the second direction, and - generate a cutting command to the cutting device (30) when said defined cutting requirements are met.

2. The trimming apparatus according to claim 1, wherein the rotational member (6) is adapted to travel along the wire during rotation, the rotational member (6) comprises a retainer assembly (44) for retaining wire loops that exit the rotational member (6) during rotation of the rotational member (6), and the retainer assembly (44) is movable up and down in a vertical direction with respect to the base frame (4).

3. The trimming apparatus according to claim 2, wherein the retainer assembly (44) comprises a plurality of finger units (45) adapted to hold the wire loops, and the finger unit (45) are movable up and down in a vertical direction with respect to the base frame (4).

4. The trimming apparatus according to claim 3, wherein the finger units (45) are openable and closable.

5. The trimming apparatus according to any of the previous claims, wherein the rotational member (6) is equipped with at least one vision sensor (46), and the rotational member (6) is arranged so that the vision sensor (46) faces downwards to identify a wire loop at an upper end ofa vertical coil (2) disposed below the rotational member (6).

6. The trimming apparatus according to any of the previous claims, wherein the rotational member (6) is provided with a wire receiving guide (24) for receiving a wire loop (3), the wire receiving guide (24) is arranged movable in a vertical direction between an extended position outside the space (8) and a retracted position inside the space (8), and the gripping device (48) is adapted to move the wire loop to the wire receiving guide (24).

7. The trimming apparatus according to any of the previous claims, wherein the trimming apparatus (1) comprises a distance sensor (18) for sensing a distance travelled along the wire during rotation ofthe rotational member (6) in the second direction, and the control unit (12) is adapted to determine the distance travelled along the wire in the second direction based on the output from the distance sensor (18), and to determine when said one or more defined cutting requirements are met based on the distance travelled along the wire from the end of the wire.

8. The trimming apparatus according to any of the previous claims, wherein the defined cutting requirements comprises one or more defined quality requirements for the wire, the rotational member (6) comprises one or more sensor units (38) for sensing one or more physical properties of the wire during the rotation in the second direction, and the control unit (12) is adapted to determine when said defined quality requirements are met based on outputs from said one or more sensor units (38).

9. Automatic trimming system (60) for trimming wire coils (2), characterized in that the trimming system comprises: - at least one trimming station (62, 64) comprises a trimming apparatus (1) according to any of the claims 1 - 9, and - a coil holder (66) arranged to hold the wire coil in a vertical direction during trimming at the trimming station.

10. The trimming system according to claim 9, wherein the trimming system (60) comprises a conveyer system (68) arranged to transport the coil holder (66) with the coil (2) to the trimming station (62) so that the wire coil is disposed below the rotational member (6) of the trimming apparatus.

11. The trimming system according to claim 9 or 10, wherein the trimming system (60) comprises a turning mechanism (70) for turning the wire coil (2) between a first verticalposition for trimming one end of the wire coil and a second vertical position for trimming the other end of the coil.

12. The trimming system according to claims 10 and 11, wherein said at least one trimming station comprises a first trimming station (62) for trimming one end of the wire coil (2) and a second trimming station (64) for trimming the other end of the wire coil, and said conveyer system (68) is arranged to transport the coil holders (66) with the wire coi|s between the first trimming station (62), the turning mechanism (70), and the second trimming station (64).