WO2016198086A1

WO2016198086A1 - A component feeder and a system for sorting components

Info

Publication number: WO2016198086A1
Application number: PCT/EP2015/062677
Authority: WO
Inventors: Daniel Sirkett; Ivan Lundberg
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2015-06-08
Filing date: 2015-06-08
Publication date: 2016-12-15
Anticipated expiration: 2017-12-08

Abstract

The present invention relates to component feeder for sorting tasks comprising a component supply device (4) arranged to supply an amount of components, and a component distributer (1) comprising a sorting table (2) having a picking surface (21) for receiving the amount of components, and a vibration device (3) arranged to cause the picking surface to vibrate. The sorting table is provided with a central opening and the component supply device is arranged to supply the amount of components to the picking surface via said central opening and the vibration device is configured to cause the picking surface to vibrate in a vertical direction in order move the components towards an outer rim (25) of the picking surface.

Description

A component feeder and a system for sorting components

Field of the invention

The present invention relates to a component feeder for sorting tasks. The present invention also relates to a system and a method for sorting components. The invention is suitable for different types of sorting tasks, for example, for sorting of scrap parts, and for sorting of components based on certain properties of the component. The properties are, for example, the size, shape, color, or material of the component.

Background of the invention

An increasing amount of scrap puts high demand on recycling the material in the scrap. Before it is possible to recycle the scrap, it is necessary to sort the scrap. It is desirable to make the sorting process automatic. It is known to use automatic systems for sorting scrap including a plurality of containers for different types of scrap, one or more industrial robots for picking the scrap components and placing the scrap component in the correct container, one or more conveyer belts for transportation of the scrap components and feeding the robot with components. The sorting system may further include a vision system for locating the components on the conveyer belt.

Metal recycling is a well-established process and effective methods are being used to sort between different types of metals. However, there is a growing demand for technologies capable of discriminating between different alloys of the same type of metal. The development in recent years of laser-based spectrometers capable of rapidly determining the proportions of different elements in a material have provided a means for identifying particular alloys of for example aluminum and steel. The use of such sensors in recycling plants allows the metals to be sorted according to their specific alloy, thus increasing revenue for the operators. However, for the sorting process to be effective, there must exist mechanical means to physically place the scrap pieces into the appropriate containers.

While e.g. eddy current separators are capable of sorting between ferrous and non-ferrous metals, and automatically diverting the scrap metal pieces to the appropriate containers, such magnetic methods cannot be used to discriminate between different alloys of the same metal. Instead, the pieces of metal need to be removed from the belt with the assistance of some kind of sensor-guidance. One way to achieve this is to use air-jets to blow the pieces of scrap off the conveyor as they pass the appropriate container. This method requires the scrap parts to be small enough to be deflected by the air jet. A more general method is to use a robot guided by a vision system to pick the parts from the conveyor. However, the efficacy of this solution is limited by the ability of the gripper to grasp objects of unknown shape, size and surface texture. Another problem is that it is difficult to grasp one particular object if there are many objects located close together on the conveyor belt. To enable picking of a certain component, the components must be separated from each other on the belt. This puts high demands on the feeding of the objects onto the conveyor belt.

Rather than lifting the components up from the surface in order to move them to their destinations, an alternative approach is to simply push the components off the surface using e.g. a brush-like tool so that they fall into appropriate containers. This method is called sweep- sorting and simplifies the process of determining an appropriate gripping strategy, since the process is reduced to a two-dimensional problem. Furthermore, since the components do not need to be lifted, the forces involved are lower, which allows a lighter-weight mechanical design of the robot, thereby facilitating higher operating speeds. Sweep-sorting is commonly used in industry for diverting components from conveyor belts, but the key to this is that the components arrive in single file with good spacing between the components. When the components are scattered over a surface at random, the task becomes more difficult. The challenge, therefore, lies in finding a way to push only the intended object without inadvertently also moving pieces lying in close proximity to the intended object, and to ensure that the component arrives at the intended destination.

Another problem with existing robotic waste picking solutions arises from the need to recirculate scrap components that are not picked on a first pass. The traditional solution is to transport the scrap on a series of two or three belts and/or lifting devices. This results in a complex and bulky arrangement with many moving parts. US8158902 describes a system for sorting metals from a batch of mixed material scrap and includes an array of inductive proximity detectors, a processing computer and a sorting mechanism. The inductive proximity detectors identify the location of the metal pieces and the processing computer instructs the sorting mechanism to place the metal and non-metallic pieces into separate containers. WO2013/113367 discloses a method and a system for feeding components. The component feeder comprises a triangular hopper for receiving and housing components, and a lift disposed adjacent to the hopper for elevating a selection of the components from the storage, and a pick surface arranged above the hopper for receiving the selection of components. The component feeder further includes a horizontally acting spreader in the form of a pusher plate configured to give the selection of components a push to spread the selection of components from the lift onto the pick surface. The component feeder may also be capable of reorienting the components by a vibrating movement of the pick surface. This vibration movement is also horizontal in order to reorient the components on the picking surface. The pusher plate moves the components from the lift to the pick surface, but it does not ensure a good spacing between the components to allow sweep-sorting of the components.

Object and summary of the invention

The present invention aims to at least partly overcome some of the above problems. According to one aspect of the invention, this aim is achieved with a component feeder as defined in claim 1.

The component feeder comprises a component supply device arranged to supply an amount of components, and a sorting table having a picking surface for receiving the amount of components, and a vibration device arranged to cause the picking surface to vibrate. A central part of the sorting table is provided with an opening, and the component supply device is arranged to supply the amount of components to the picking surface via said opening and the vibration device is configured to cause the picking surface to vibrate in order move the components towards an outer rim of the picking surface. The picking surface is a surface supporting unsorted components. The picking surface is located adjacent to the component supply device. The component supply device is arranged to supply the components in the vicinity of a central part of the picking surface and accordingly at a distance from the outer rim of the sorting table. Since the sorting table is provided with a central opening, and the component supply device is arranged to supply the amount of components to the picking surface via the central opening, the components are supplied at a distance from an outer rim of the sorting table. The components are then distributed on the picking surface by causing the picking surface to vibrate and by that radially moving the components towards the outer rim of the picking surface. Thus, an efficient distribution of the components over the picking surface is accomplished, and accordingly picking of a certain component is facilitated. The present invention, for example, makes it possible to provide a robot-based solution for sorting of larger items of metal scrap based on the sweep-sorting principle. Further, a simple and compact component feeder is achieved.

According to an embodiment of the invention, the vibration device is configured to cause the picking surface to vibrate in a vertical direction. Due to the vertical vibrations of the sorting table, the components are move outwards towards the outer rim of the sorting table, and by that the components are separated from each other. The table is vibrated during a period of time, which is long enough to separate the components. When the components have been separated, the vibrations are stopped and the components can be moved away from the picking surface. For example, the components can be picked by a gripping tool and then moved away to an appropriate container, or moved away from the picking surface and into the containers by using sweep-sorting.

According to an embodiment of the invention, the outer rim of the sorting table is circular. Accordingly, the outer rim of the picking surface is circular. A circular picking surface provides an optimal distribution of the components during the period of vibration, where the components will move in a radial direction towards the outer rim. The sorting table can have other shapes, for example, a hexagonal shape. According to an embodiment of the invention, the sorting table is resiliently suspended in a vertical direction. Thus, the sorting table is enabled to move in a vertical direction during the period vibrations.

According to an embodiment of the invention, the sorting table is provided with a centra l opening. For example, the sorting table is annular, whereby the picking surface is formed around the central opening of the ring. The component supply device is arranged to supply the sorting table with components so that the components are positioned on the picking surface of the sorting table around the central opening of the table and at a distance from the outer rim of the sorting table. The components that have been supplied to the sorting table will be positioned at about the same distance from the outer rim. This embodiment provides for an even distribution of the components.

According to an embodiment of the invention, the component supply device comprises a component storage having an upper and a lower end, an opening arranged in the upper end of the storage, and a movable floor configured to be raised and lowered between the upper and lower end of the storage, and the sorting table is arranged at the upper end of the storage with its central opening aligned with the opening of the component storage. The components are supplied to the picking surface by raising the floor. Thus, the pusher plate in the prior art component feeder can be omitted.

In this embodiment, the sorting table is suitably ring shaped with a central opening. The sorting table is then arranged concentrically with the component storage. The sorting table is located with its inner rim adjacent to a wall of the component storage. The sorting table may be arranged rotatable around the component storage. The component supply device may further comprise a conveyer belt arranged to supply the component storage with components. The component storage is provided with a moving mechanism for lowering and raising the floor of the storage. Once the component storage has been filled with components to be sorted, the moving mechanism causes the floor to be moved upwards a short distance sufficient to cause a small amount of components to overflow onto the sorting table. Following this, the floor descends once more, leaving a narrow ring of components distributed around the inner rim of the sorting table. This embodiment enables an optimal positioning of the components to allow them to be evenly distributed over the entire surface of the sorting table during the vibration period. Another advantage is that the component feeder is compact. Space needed for sorting components, such as scrap, is reduced using the feeder of the present invention.

According to an embodiment of the invention, at least a part of the picking surface is sloping towards the outer rim of the sorting table. For example, the picking surface can be convex. This embodiment facilities the components to be moved towards the outer rim of the sorting table during vibration.

In an alternative embodiment, the picking surface of the sorting table is flat. The vibration device is configured to cause the sorting table to oscillate in a vertical direction, i.e. in a direction substantially orthogonal to the area of distribution of the table. Suitably, the vibration device comprises one or more electromagnets arranged to cause the sorting table to oscillate. The electromagnets are suitably arranged below the sorting table and arranged to cause the sorting table to oscillate in a vertical direction.

According to an embodiment of the invention, at least a part of the sorting table comprises a magnetic material, and the vibration device comprises one or more electromagnets arranged to cause the sorting table to vibrate or oscillate by alternately attracting and not attracting the sorting table during the period of time. By using electromagnets it is easy to control the vibrations of the sorting table. Due to the fact that the sorting table is resiliently suspended in a vertical direction, the sorting table is caused to oscillate in a vertical direction.

According to an embodiment of the invention, the vibration device comprises a plurality of electromagnets arranged below and at a distance from the sorting table, and the electromagnets are positioned at a distance from each other. For example, a resilient material is arranged between the table and the electromagnets.

According to an embodiment of the invention, the sorting table comprises one or more elements made of a magnetic material positioned above the one or more electromagnets of the vibration device. For example, the sorting table is provided with a plurality of discs of steel arranged on an under side of the table facing the electromagnets. Suitably, each disc is facing one of the electromagnets.

According to an embodiment of the invention, the vibration device is arranged to cause the sorting table to vibrate with a frequency between 5 and 100 Hz, and preferably with a frequency between 30 and 70 Hz. This rather high frequency causes the components to move evenly, i.e. without jumping, towards the outer rim of the sorting table, and thus without reorientation of the components. However, the frequency may vary depending on the size and weight of the components.

According to an embodiment of the invention, the sorting table is arranged rotatable about a central axis. In this embodiment, the sorting table is acting as a turn table. If a plurality of containers are arranged around the sorting table in different radial directions, the table can be rotated so that an identified component, which is to be sorted, is aligned with and close to the correct container. Thus, the component can easily be moved into the correct container, for example, by brushing the component into the container. Thus, the distance the movable mechanical unit has to move the component is reduced.

A further advantage with a rotatable sorting table is that a stationary sensor can be used for locating components on the turn table. The sorting table does not rotate during the separation process. Once the components have been distributed over its surface, the sorting table begins to rotate slowly. During rotation, the components pass under the sensor, for example a line- scan camera or a 3D laser profiling scanner, and the locations of the components are determined. The components will follow a circular trajectory during the rotational movements.

According to an embodiment of the invention, the sorting table is arranged rotatable in at least one direction, the component feeder comprises a diverter arm arranged movable between a position in which the diverter arm is at a distance from the sorting table and at least one diverting position in which the diverter arm extends across the picking surface of the sorting table from the outer rim to the central opening. Suitably, a component storage is positioned beneath the central opening of the table. Thus, in a diverting position, the diverter arm causes the components rotating on the sorting table to be diverted towards the central opening of the sorting table, where the components fall off an inner rim and into the component storage. This embodiment provides a fast emptying of the sorting table. This embodiment also simplifies recirculation of components that are not picked or brushed off the table on a first pass. According to an embodiment of the invention, the sorting table is arranged rotatable in a forward rotational direction and in a reversed rotational direction, and the position of the diverter arm in combination with the rotational direction of the sorting table causes the components on the sorting table to either be diverted towards the central opening ortowards the outer rim of the sorting table. Suitably, the diverter arm is arranged rotatable about an axis parallel to the central axis of the sorting table. The diverter arm may be arranged rotatable between a first diverter position and a second diverter position. In the first diverter position, the diverter arm can be used to direct the components towards the central opening of the sorting table, where the components can be recirculated. In the second diverter position, the diverter arm can be used to direct the components towards the outer rim of the table, where they may fall into a purge bin. This embodiment provides a fast emptying of the sorting table, and makes it possible to return residual components to the component storage.

According to another aspect of the invention, the aim of the invention is achieved with a system for sorting components as defined in claim 11. The system comprises a component feeder according to the invention, a sensor system arranged to locate the components on the sorting table, a plurality of containers for receiving the sorted components, and one or more movable mechanical units moving the components from the sorting table to the containers. The sensor system is, for example, a vision system. The movable mechanical unit can be any type of mechanical unit suitable for picking and placing parts, such as serial articulated robot arms, Cartesian linear manipulators, 3D cable- driven robots, parallel kinematic robots, etc.

The proposed system is faster, more robust, easier to control, and more compact than existing robot-based solutions for sorting components. According to an embodiment of the invention, the system comprises a component feeder including a rotatable sorting table, the plurality of containers are arranged radially around the component feeder, and the robot is provided with a brush for brushing the components off the surface of the sorting table and into the containers. The sorting table is rotated to move the component, which is to be sorted, to the correct container and the movable mechanical unit moves the brush towards the outer rim of the table and brushes the component into the correct container. Thus, the components are brushed off the picking surface of the sorting table into a container rather than being lifted up from the surface by a gripping device, as in the prior art.

The invention also relates to a method for sorting components according to the invention as defined in claim 13. The method comprises:

- supplying a number of components to the picking surface so that most of the components are positioned at a distance from the outer rim of the sorting table,

- vibrating the sorting table using the vibration device, which causes the components on the picking surface to move radially outwards towards the outer rim of the sorting table, - locating the components on the sorting table by means of the sensor system, and

- moving the components using the movable mechanical unit into the containers.

According to an embodiment of the invention, the components are moved into the containers by sweeping the components into the containers.

According to an embodiment of the invention, the system comprises a component feeder including a component storage with a movable floor, and the method further comprises:

- supplying the components to the component storage,

- supplying a number of components to the sorting table by raising the movable floor of the component storage a distance above the picking surface of the sorting table in order to cause an amount of the components in the component storage to overflow onto the sorting table, and subsequently, lowering the movable floor towards the lower end of the component storage. According to an embodiment of the invention, the method comprises rotating the sorting table and letting the components pass by the sensor system, whereby information from the sensor system is processed and the locations and desired containers for the components are determined, and moving the components into the desired containers using the movable mechanical unit. The invention is suitably used for waste recycling. However, the invention can also be used for other types of sorting tasks.

Brief description of the drawings

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

Fig. 1 shows a perspective view from above of a section of a component feeder according to an embodiment of the invention.

Fig. 2a shows a view from above of the component feeder and containers for the housing the sorted components.

Fig. 2b shows a cross section A-A through the component feeder.

Figs. 2c-d show an upper part of the component feeder in more detail.

Fig. 3 illustrates a moveable floor of a component supply device.

Fig. 4 shows a perspective view from below of a system for sorting components including the component feeder shown in figure 1.

Figs. 5a-d illustrates a sorting method using the component feeder of figures 1 and 2. Fig. 6 shows an embodiment of a component feeder including a diverter arm.

Figs. 7a-c illustrate the function of a diverter arm in the component feeder.

Fig. 8 shows a system for sorting components including a sensor system and a robot.

Fig. 9 illustrates sweeping of a component by a robot using a brush. Detailed description of preferred embodiments of the invention

Figure 1 shows a component feeder suitable for sorting tasks, for example sorting waste or other types of components. The component feeder comprises a component distributer 1 comprising a sorting table 2, a vibration device 3 arranged to cause the sorting table 2 to vibrate during a period of time, and a component supply device 4 arranged to supply the sorting table with components to be sorted. The sorting table has a picking surface 21 adapted for receiving components, such as scrap parts, and an under surface 22. The sorting table is, for example made from magnetic steel, or has one or more magnetic steel portions on its underside.

The sorting table 2 has an outer rim 25. The outer rim 25 of the sorting table is preferably circular, but may have any other shape, such as a hexagonal shape. The sorting table may have the shape of a ring, as shown in figure 1. The sorting table may have a central opening 23, and an inner rim 24 extending along the central opening. The picking surface 21 may be flat and extending substantially orthogonally in relation to a central axis X of the table. In an alternative embodiment, at least a part of the picking surface may slope towards the outer rim 25, i.e. the outer rim is at a lower level compared to the inner rim. The component feeder further includes a support structure 26 for supporting the sorting table 2. In this embodiment, the support structure is cylindrical and arranged coaxially with the table. The sorting table 2 is attached to an upper end of the support structure 26. The support structure 26 may also be arranged coaxially with the component supply device 4 and surrounding an upper part of the component supply device 4. The support structure 26, and accordingly the sorting table 2 may be attached to the component supply device 4. The support structure 26 may include a wall extending from the inner rim of the sorting table substantially orthogonally from the surface of the sorting table toward the ground level.

The sorting table 2 is preferably resiliently suspended to enable the table to vibrate. For example, the support structure comprises one or more resilient members 28. The resilient member 28 is arranged to be compressed when a vertical force, i.e. a force acting in a direction parallel to the central axis X of the sorting table, is acting on the resilient member, and to be decompressed when the force ceases and by that causing the table to vibrate in a vertical direction, i.e. in a direction parallel to the central axis X of the sorting table. The resilient member 28 is made of a resilient material, for example, of foam rubber. The resilient member 28 can, for example, be a ring made of rubber.

Figure 2a shows the component feeder including the sorting table 2 and the component supply device 4 from above. The system further comprises a plurality of containers 8a-c for receiving the sorted components. The containers are formed between walls 81 extending radially from the component feeder.

Figure 2b shows the component feeder in a cross-section A-A. Figure 2c shows an enlarged view of a section C of the component feeder as indicated in figure 2b. Figure 2d shows an enlarged view of a section D as indication in figure 2c. In this embodiment, the wall of the support structure 26 is divided into an upper wall section 26a and a lower wall section 26b, and the resilient member 28 is positioned between the upper and lower wall sections. The table 2 is elastically coupled to the journalled support structure via the resilient member 28, e.g. a rubber ring, interspersed between the two wall sections.

The support structure 26, and accordingly the sorting table 2 may be rotationally attached to the component supply device 4. However, it is necessary that the sorting table can be rotated. In one embodiment of the invention, the sorting table may be arranged rotatable about the central axis X. The support structure 26 may comprise one or more rotational bearings 27 for the rotational attachment. The resilient member 28 is positioned above the bearings 27. An actuator, such as a motor, may be used to rotate the sorting table. The sorting table 2 may be rotatable in a forward rotational direction. In an alternative embodiment, the sorting table 2 is arranged rotatable in a forward rotational direction as well as in a reversed rotational direction.

The vibration device 3 is arranged to cause the sorting table to vibrate in a vertical direction, i.e. in a direction parallel to the central axis X of the sorting table. In this embodiment the vibrations are caused by means of one or more electromagnets acting on the sorting table. For this purpose, the sorting table comprises a magnetic material. The sorting table may comprise one or more magnetic elements 29 made of a magnetic material positioned at the under surface 22 of the sorting table, as shown in figure 2d. For example, the magnetic element 29 is a ring of steel attached to the under surface 22 of the table. The magnetic element 29 can also be embedded in the sorting table. The magnetic element 29 may be attached in any way suitable for the operation of the component feeder. If the sorting table is made of a magnetic material, for example steel, the magnetic element 29 can be omitted.

The vibration device 3 may be positioned below and at a distance from the under surface 22 of the sorting table to allow the table to move vertically during the vibration. In this embodiment, the vibration device is supported by the walls 81 forming the containers 8a-c for receiving the sorted parts. The vibration device 3 is supported on the top of the radial walls 81 forming the different containers. The walls 81 forming the containers 8a-c are provided with indentions 82 designs for receiving and supporting the vibration device 3. The vibration device 3 may be attached to the walls 81.

In this embodiment, the vibration device 3 comprises a plurality of electromagnets 31 and a holder 30 for holding the electromagnets. For example, the holder 30 is a vibration ring 30a including a plurality of electromagnets 31, as shown in figure 4. The electromagnets 31 are positioned at a distance from each other in different radial directions along the vibration ring 30a, as shown in figure 4. Preferably, the electromagnets 31 are arranged such that the magnetic element 29 is facing the electromagnets 31, as shown in figure 2d. The electromagnets 31 may be embedded in the vibration device. The electromagnets may be attached in any way suitable for the operation of the component feeder. The ring 30 of electromagnets is located underneath the table 2 near to its inner rim 24. The vibration ring 30 is suitably arranged coaxial with the central axis X of the sorting table. The vibration ring

30 may rest on or be attached to the wall 81, as shown in figure 2d.

An electromagnet 31 is a type of magnet in which a magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Each electromagnet includes a coil supplied with DC or AC current from a power source (not shown). The table 4 is caused to vibrate by alternatingly turning on and off the power supply to the electromagnets

31 with a certain frequency. The one or more electromagnets 31 then alternately attract and not attract the sorting table, and thus cause the sorting table to oscillate or vibrate. The sorting table are vibrated during a certain period of time in order to separate the components or objects on the table. The vibration device is configured to cause the sorting table to oscillate in a vertical direction extending along the central axis X of the table. The frequency of the vibration is adapted to cause the components to move from the central opening 23 towards the outer rim 25 of the sorting table. The frequency may vary and depends on the size and weight of the components. The vibration device may be arranged to cause the sorting table to vibrate with a frequency between 5 and 100 Hz, preferably with a frequency between 30 and 70 Hz. The vibration continues for a period of time, which period may vary and depends on the size and weight of the components. The vibration period is typically between 2 and 10 seconds. Vibration may, for example, be stopped when one or a few of the components on the sorting table first reach a position close to the outer rim of the sorting table. The sorting table does not rotate during the separation process.

The sorting table is caused to vibrate by turning on and off the electromagnets with a defined frequency. The electromagnets can be turned on and off synchronously, i.e. at the same time. Alternatively, the electromagnets can be turned on and off successively so that the sorting table is caused to wobble. The electromagnets are turned on by energizing the coil, i. e. by supplying the coil with power. The electromagnets are turned off by de-energizing the coil, i. e. by turning off the power supply to the coil. The component feeder may further comprise a control unit (not shown) for controlling the vibrations of the sorting table. The control unit controls the power supply to the electromagnets, and by that the frequency of the vibrations and the duration of the vibration, i.e. the period of time of the vibrations. The control unit may be provided with a user interface for setting a desired frequency and duration of the vibrations. The user interface may also be provided with means enabling a userto initiate start of a vibration period. Alternatively, the vibration period is started automatically. The control unit comprises, for example, a computer or other similar intelligent devices, comprising software code portions, such as a computer program, comprising instructions for control of the power supply to the electromagnets, and hardware, such as a processor, memory and input/output devices, for carrying out the instructions of the computer program. The control unit comprises one or more switching devices for switching the power supply to the electromagnets in response to the instructions from the computer.

As an alternative to using electromagnets to produce vibration of the table 2, the resilient member 28 can be wholly, or in sections, made from a material whose geometry changes in response to stimulus from e.g. an applied electrical field or current. Such materials include piezo ceramics, electro-active polymers, shape-memory alloys, etc. The resilient member 28 can alternatively contain an inflatable portion into which air is alternately pumped and removed in order to produce vibrations.

The component supply device 4 comprises a component storage 41 having an upper end 42 and a lower end 43, as shown in figure 2b. In this embodiment, the component storage 41 is cylindrical and arranged coaxially with the sorting table 2. The sorting table is arranged in the upper end of the component storage. The component storage 41 has an opening 44 arranged in the upper end 42 of the component storage. The opening 44 of the component storage is aligned with the central opening 23 of the sorting table so that components can be moved between the component storage 4 and the sorting table 2 via the openings 23 and 44. The sorting table 2 is arranged at the upper end 42 of the component storage 41 with its central opening 23 aligned with the opening 44 of the component storage.

Figure 3 illustrates the function of the component supply device 4. The component storage 41 of the component supply device 4 comprises a movable floor 45 configured to be raised and lowered between the upper and lower ends 42, 43 of the component storage. In this embodiment of the invention, the movable floor45 has a conical profile, for example of about 45°, in order to ensure that every last piece of component can be dispersed onto the sorting table. The floor 45 may be lifted using any lifting means 46. For example, a commercially available "Spi ra lift" actuator (Paco Spiralift Inc. Quebec, Canada), may be used, including an actuator comprising two coils of interlocking stainless sheets, which telescope upwards to form a stable, pre-stressed column.

Figure 4 shows an example of a system for sorting components including the component feeder shown in figure 1. The system further comprises plurality of containers for receiving the sorted components. The containers are formed between walls 81 extending radially outwards from the component feeder. The system further comprises a movable mechanical unit, such as a robot 10, moving the components from the sorting table to the containers. In this embodiment, the movable mechanical unit is a 3-axis parallel-kinematic picker robot. A parallel kinematic manipulator (PKM) is defined as a manipulator comprising at least one stationary element, denoted a base frame, a movable element, denoted a platform or end effector, and usually three arms. Each arm comprises a link arrangement connected to the movable element. Each arm is actuated by an actuator preferably arranged on the stationary element to reduce the moving mass. The link arrangements transfer forces to the movable element. The movable element may include a tool flange for connecting a tool.

An actuator 92, such as a motor, is arranged to rotate the sorting table. A power means 94, such as a motor, is arranged to move the floor of the component storage 41.

Figures 5a-d illustrate the function of a component feeder according to an embodiment of the invention, and in particular the process of separating the components to be sorted using the sorting table 2 and the vibration device. The component supply device 4 is first filled with components to be sorted, as shown in figure 5a. The components are then transported up to the table 2 by raising the movable floor 45, for example by extending the Spiralift mechanism, as shown in figure 3. The movable floor 45 is then lowered, for example by descending the Spiralift. Then a narrow ring of components is left on the table close to its inner rim 24, as shown in figure 5c. Vibration is then induced in the table by the electromagnets, causing the components to travel radially outwards and separate from each other, as shown in figure 5d.

The components to be sorted are supplied to the sorting table 2 so that most of the components are positioned close to the inner rim 24 of the sorting table 2, and thus at a distance from the outer rim 25 of the sorting table, as shown in figure 5c. When power is applied to the electromagnet in pulses, the sorting table 2 is periodically attracted to the electromagnets and then flexes away as the resilient element 28 is compressed and returns to its normal form. This induces vertical vibrations in the table, which cause the components lying on the picking surface 21 to march radially outwards towards the outer rim 25 of the sorting table, as illustrated in figure 5d. The sorting table may be optionally equipped with a slight outward cone profile, of between 0.5 and 5 degrees to help with the outwards motion. Since the components move in a radial direction, they simultaneously move apart from one another, thus inducing separation in two directions. Vibration is applied until the first components begin to reach the outer edge 25 of the table. This point can be detected by a vision system or through some other discrete sensing method such as e.g. inductive sensors embedded into the table (not shown).

Figure 6 shows an embodiment of a component feeder including a diverter arm 5. In this embodiment, the sorting table is arranged rotatable about the central axis X. Preferably, the sorting table is arranged rotatable in a forward and a reversed direction. The diverter arm 5 is arranged above the sorting table 2 and rotatable about an axis X2, which is parallel to the central axis X and positioned outside the sorting table 2. A power means 95, such as a motor, may be used to rotate the diverter arm. Figures 7a-c illustrate the function of the diverter arm. In this embodiment, the diverter arm is triangular. The diverter arm may have one concave surface 5a and one flat surface 5b. The diverter arm 5 is arranged movable between a first position in which the diverter arm is at a distance from the sorting table, as shown in figure 7c, and a second diverter position, as shown in figure 7a, and a third diverter position, as shown in figure 7b. In the second and a third diverting positions the diverter arm 5 extends across the picking surface 21 of the sorting table from the outer rim 25 to the central opening 23. The diverting position of the diverter arm in combination with the rotational direction of the sorting table causes the components on the sorting table to either be diverted towards the central opening or towards the outer rim of the sorting table. In the first diverter position, the diverter arm 5 can be used to direct the components towards the central opening 23 of the sorting table, where the components fall off the inner rim 24 and into the component storage 41, by rotating the table 2 in a reversed rotational direction, as shown in figure 6 and 7a. In the second diverter position, the diverter arm can be used to direct the components towards the outer rim 25 of the table, where they may fall into a purge bin 8c, by rotating the table 2 in a forward rotational direction, as shown in figure 7b.

Figure 8 shows a system for sorting components including a sensor system and a robot. The component feeder as described above may be part of a system for sorting components, such as scrap. The system may further comprise a sensor system including a sensor 7a arranged to locate the components on the sorting table and a sensor 7b for determining a certain property of the component, for example, the material of the component. The sensor 7a may be a stationary sensor for locating components on the sorting table. The sensor system is positioned above the sorting table at a distance suitable for operating the sensors. The sensor 7a may be a line-scan camera or a 3D laser profiling scanner. The system may also comprise a sensor 7b for identifying the material of the component, such as a scanning laser induced breakdown spectroscopy (LIBS) sensor. The system may further comprise a plurality of containers 8a-c for receiving the components sorted according to the determined property, and a robot 10 for moving the components from the sorting table to the containers. The plurality of containers 8a-c may be arranged radially around the component feeder. The system may further comprise a conveyer belt 9 for supplying components to the component storage 41 at the end of the conveyer belt 9.

Figure 9 illustrates sweeping of a component 13 by a robot 10 using a brush ll.The robot 10 may be provided with any means to move the components from the sorting table and into one of the containers 8a-c. For example, the robot can be provided with a brush 11 for brushing the components off the picking surface 21 of the sorting table and into the containers, as shown in figure 9.

An example of a method for sorting components 13 using a system according to the invention will now be explained. The components 13 are supplied to the component storage 41 from the conveyer belt 9. At the end of the conveyer belt 9, the components 13 are dropped into the component storage 41 through the opening 44. The components are made of different alloys, which is illustrated using different filling patterns. Once the storage 41 is filled with components, the movable floor 45 is raised by extending the Spiralift actuator. The floor is raised a short distance above the picking surface 21 of the sorting table in order to cause a small amount of components to overflow onto the sorting table as shown in figure 5b. Subsequently, the movable floor is lowered towards the lower end 43 of the component storage. A narrow ring of components are now distributed on the sorting table around the inner rim 24, as shown in figure 5c. Then, the power source of the vibration device is turned on, whereby the vibration device 3 causes the sorting table to vibrate. The power is preferably applied with impulses so that the sorting table is periodically attracted to the electromagnets 31 in pulses and then flexes away as the resilient member or rubber ring compresses and returns to its normal form. This induces vertical vibrations of the sorting table, which cause the components on the picking surface 21 to move radially outwards towards the outer rim 25 of the sorting table. Vibrations are applied until the first component 13 begins to reach the outer rim of the sorting table. The sorting table does not rotate during the separation process. The following steps are optional. Once the components are distributed over the picking surface, the sorting table is rotated slowly, whereby the components follow a circular trajectory during the rotational movements. The rotational speed is adapted so that the components remain in a fixed position on the sorting table, i.e. the centrifugal force of the rotation is not high enough to cause the components to move towards the outer rim 25. During rotation the components pass underthe sensor 7a, such as a camera. Information from the sensor is processed and the locations and desired destinations of the components are calculated. Sweeping is then commenced by starting to sweep or brush components lying nearest to the outer rim as illustrated in figure 9. Once the components around the outer rim have been removed, a free path is available for the components whose access to the outer rim was previously blocked by components lying in front of the outer rim. Sweeping continues until no more sweepable components remain on the sorting table. Non-sweepable components are defined as either: 1) those of one material lying so close to another component of a different material that the brush is unable to sweep one component without also sweeping the neighbouring component (two components of the same material lying close to each other can be swept at the same time into the appropriate container), or 2) contaminant components made from unwanted or unidentifiable materials (such as e.g. non- metals in a metal recycling application). The non-sweepable components are finally returned to the component storage 41 or the purge bin 8c using the diverter arm 5 in a first or second diverting position respectively. Once the component storage is empty, the process can start all over again by filling the storage 41 with new material from the conveyer belt 9.

The proposed system and method offers a number of advantages over a traditional on-line conveyor-based sorting systems in which scrap pieces are picked up and moved using a gripper. The proposed system has a small workspace footprint, operates using a single, highspeed robot, and is able to sort scrap pieces of any shape or size, within reasonable limits, as defined by the width of the sorting table and the diameter of the containers. Mechanically, the system is simple since recirculation of missed or un-sortable scrap pieces occurs through the use of a simple diverter arm. By contrast, an online conveyor-based system needs at least two further conveyors or a conveyor and a lift in order to recirculate scrap. The system also has two features which help with fast changeover from one batch of scrap pieces to another. Firstly, the relative volume of the containers can be adjusted to match the expected distribution of a batch simply by changing the angular position of the dividing walls 81 around the periphery of the component storage. It is also possible to add new dividing walls should additional sorting compartments be required.

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, a retaining wall may be positioned between the conveyer belt and the outer rim of the sorting table. The component storage may comprise an additional opening (not shown) near the lower end 43 for removal of components. Also, the robot and the sensor share information using hardware and software in order for the robot to select the correct component and put it into the correct container. The components can be picked from the sorting table using other methods than sweeping, for example, using a mechanical gripping tool or an electromagnet. It is also possible to have more than one robot to increase sorting speed, for example, a system with three picker robots for higher speed sorting.

Claims

1. A component feeder for sorting tasks comprising a component supply device (4) arranged to supply an amount of components, a sorting table (2) having a picking surface (21) for receiving the amount of components, and a vibration device (3) arranged to cause the picking surface (2) to vibrate, characterized in that the sorting table (2) is provided with a central opening (23), and the component supply device (4) is arranged to supply the amount of components to the picking surface via said central opening, and the vibration device (3) is configured to cause the picking surface to vibrate in order move the components towards an outer rim (25) of the picking surface.

2. The component feeder according to claim 1, wherein the sorting table is resiliently suspended in a vertical direction.

3. The component feeder according to any of the previous claims, wherein said outer rim (25) of the picking surface is circular.

4. The component feeder according to any of the previous claims, wherein the component supply device (4) comprises a component storage (41) having an upper end (42 and a lower end (43), an opening (44) arranged in the upper end of the component storage, and a movable floor (45) configured to be raised and lowered between the upper end and the lower end of the component storage, and the sorting table (2) is arranged at the upper end of the component storage with its central opening (23) aligned with the opening (44) of the component storage.

5. The component feeder according to any of the previous claims, wherein at least a part of the picking surface (21) is sloping towards the outer rim (25) of the sorting table.

6. The component feeder according to any of the previous claims, wherein at least a part of the sorting table comprises a magnetic material (29), and said vibration device (3) comprises one or more electromagnets (31) arranged to cause the sorting table to vibrate by alternately attract and not attract the sorting table.

7. The component feeder according to any of the previous claims, wherein said vibration device (3) is arranged to cause the sorting table (2) to vibrate with a frequency between 5 and 100 Hz, preferably with a frequency between 30 and 70 Hz.

8. The component feeder according to any of the previous claims, wherein the sorting table (2) is arranged rotatable about a central axis (X).

9. The component feeder according to any of the previous claims, wherein the component feeder comprises a diverter arm (5) arranged movable between a position in which the diverter arm is at a distance from the sorting table (2) and at least one diverting position, in which the diverter arm extends across the picking surface (21) from the outer rim (25) to the central opening (23).

10. The component feeder according to claim 9, wherein the sorting table (2) is arranged rotatable in a forward rotational direction and in a reversed rotational direction, and the diverting position of the diverter arm (5) in combination with the rotational direction of the sorting table causes the components (13) on the sorting table to either be diverted towards the central opening (23) or towards the outer rim (25) of the sorting table.

11. A system for sorting components (13), wherein the system comprises:

- a component feeder according to any of the claims 1 - 12,

a sensor system (7) arranged to locate the components (13) on the sorting table (2), a plurality of containers (8) for receiving the sorted components, and

at least one movable mechanical unit (10) for moving the components from the sorting table to the containers.

12. The system according to claim 11, wherein said plurality of containers (8) is arranged radially around the component feeder, and the at least one movable mechanical unit (10) is provided with a brush for brushing the components (13) off the surface of the sorting table (2) into the containers.

13. A method for sorting components (13) using a system as defined in claim 11 or 12, wherein the method comprises:

- supplying a number of components (13) to the sorting table so that most of the components are positioned at a distance from the outer rim (25) of the sorting table,

- vibrating the sorting table using the vibration device (3), which causes the components on the picking surface (21) to move radially outwards towards the outer rim (25) of the sorting table,

- locating the components (13) on the sorting table by means of the sensor system, and

- moving the components into the containers (8) using the movable mechanical unit (10).

14. The method according to claim 13, wherein the system comprises a component feeder according to claim 5, and the method further comprises:

- supplying the components (13) to the component storage (41), and supplying a number of components (13) to the picking surface (21) by raising the movable floor (45) of the component storage a distance above the picking surface (21) in order to cause an amount of components in the component storage to overflow onto the sorting table, and subsequently, lowering the movable floor towards the lower end (43) of the component storage.

15. The method according to claim 13 or 14, wherein the method comprises rotating the sorting table and letting the components pass by the sensor system (7), whereby information from the sensor system is processed and the locations and desired containers for the components are determined, and moving the components into the desired containers (8) using the movable mechanical unit (10).