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(11) | EP 4 461 433 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | INSTALLATION FOR THE MAINTENANCE, IN PARTICULAR THE CLEANING, OF A CASTING TABLE ASSEMBLY AND AUTOMATED MAINTENANCE METHOD USING SUCH INSTALLATION |
| (57) This installation (I) comprises a main robot (3), said main robot comprising a body
as well as coupling means (34) mobile with respect to said body, a starting head grab
device (40), a brushing device (42), for brushing upper part of casting table, a screw
device (44), for screwing/unscrewing each mould of the casting table with respect
to upper table; and a mould grab device (46), each device being provided with complementary
coupling means (402, 422, 442, 462) adapted to cooperate with main robot so as to
permit a removable attachment between each main operative device and said main robot. Moreover, the installation is provided with control means (9) comprising a human machine interface (90), control lines (95-98) adapted, upon receipt of inputs actuated by an operator, to transmit control orders to at least said main robot (3), said displacement means (37) and Prior art maintenance is essentially based on manual operations. The installation and method according to the invention enable the user to facilitate the maintenance of casting tables, moulds and mould components such as starting heads. |
Technical field of the invention
[0001] The invention relates to casthouse technology, and more precisely to mold tables used for vertical semi-continuous casting of billets. Such mould tables are most often used in aluminium industry; they are also used for casting billets in copper, magnesium and other non-ferrous metals. Similar mould tables and moulds can be used for horizontal casting processes, and for casting ferrous metals. The invention pertains to an installation for the cleaning of mould tables, in which numerous individual steps for handling, disassembling, cleaning, and reassembling of mould tables and components thereof can be simplified and automatized using robots, appropriate exchangeable devices and sensors.
Prior art
[0002] Liquid metal obtained from electrometallurgical or other chemical reduction processes, if not directly used for the manufacturing of castings, needs to be cast into shapes such as rolling ingots and extrusion billets in order to render the metal usable for further processing. Such rolling ingots and extrusion ingots are long parts of constant cross section. They can be obtained by vertical semi-continuous casting, or by horizontal casting.
[0003] Vertical semi-continous casting utilizes a vertically oriented mould situated above a casting pit that extends beneath the floor level of the casthouse. Usually, a plurality of such moulds are provided in a horizontal mould table. The lower component of the vertical casting mould is a starting block (also called « starting head » or « stool cap »). When the casting process begins, the starting blocks are in their highest upward position and in the moulds. During casting molten metal is poured onto the upper part of the mould table, where it is carried through a system of branched casting launders to spouts into the mould bores or cavities. The starting block, sitting on the top of a stool, is lowered at a predetermined rate (usually by hydraulic means), and solidified metal emerges from the bottom of the moulds; in this way long ingots are formed which can have a length of more than ten meters, said length being limited by the depth of the casting pit. Their cross section is determined by the mould geometry and is selected in order to suit their intended use. As the external, soldifying surface of the emerging metal strand is cooled (usually by water), this process is therefore called chill casting.
[0004] Such mould tables and moulds are known as such and are commercially available from several manufacturers. They are used for casting ferrous and non-ferrous metals and alloys, such as aluminium, brass, lead, copper, magnesium, steel. The present invention is directed to a system intended to be used in aluminium industry but is not limited to such use.
[0005] As an example, WO 2009/025874 (assigned to Wagstaff) discloses a mould and bottom block system for vertical semi-continous chill casting of aluminium. The geometry of a mould table system is described in detail in US 7,296,613 and EP 2 051 825 (both assigned to Wagstaff). US 4,598,763 (Wagstaff) describes the structure of an annular billet casting mould and its starting block.
[0006] It is well known that the state of the mould and its components may directly affect the quality of the cast metal ingot. Mould tables, moulds and stool caps require regular cleaning, inspection and maintenance. More precisely, molten metal, such as aluminium, can be very sticky when it is running through the casting launders, and every more when it gets solidified. Some of these surfaces (such as casting launders) are made from ceramic materials, other are metallic materials. To avoid accumulation of layers of solified metal, specific active substances are applied onto all the surfaces in contact with liquid metal. As a consequence, any surface that is in contact with liquid metal needs to be cleaned and inspected once the casting process is finished, and may need to be coated, repaired or replaced if needed.
[0007] According to the state of the art most of these operations are carried out manually once the mould table has been removed from the casting pit. These operations include a significant number of individual operations of inspection of surfaces and mechanical parts, cleaning of surfaces, unfastening and fastening of fixing elements, removal and repositioning of moulds, and so on.
[0008] Prior art maintenance of casting tables leads to several disadvantages. Indeed, said maintenance is essentially based on manually operated tasks, which constitute very tedious works. For instance, workers may be exposed to dangerous products, while being subjected to physical injuries, in particular due to the weight of transported mechanical elements. As an example, the upper part of the mold table, including the system of branched casting launders, needs to be cleaned by a brush; this is a tedious task in which the workers are exposed to the produced dust. It should also be noted that a purely manual maintenance may induce some severe lacks, in the quality of the maintenance itself.
[0009] Moreover, removal of the moulds and theoir components is also a dangerous task, according to prior art proceedings, as they may fall down during handling, or they may lead to finger jamming during fitting in or during manual removal. Such manual removal may also imply unconfortable positions and/or repeated manual lifting of heavy workpieces. Screwing and unscrewing of moulds and starting heads, even if carried out with automatic screwdrivers, may further imply repeated movements.
[0010] As a consequence, there is a need to provide a device for cleaning and preparation of mould tables and their components, which makes it possible to remedy to the above drawbacks.
Objects of the invention
[0011] In this respect a first object of the invention is an installation for the maintenance, in particular the cleaning, of a casting table assembly, said casting table assembly comprising
an upper part, also called upper table (10), said upper table comprising a rectangular frame (100), a plurality of openings (110) provided in the frame, a plurality of moulds (12), each facing a respective opening, and removable attachment means (13), in particular bolts, making it possible to attach said moulds with respect to said frame,
a lower part, also called lower table (15), said lower table (15) comprising a body (150), a plurality of so-called starting heads (18), each being intended to be inserted into a respective mould, and locking means (19) making it possible to lock said starting heads with respect to said body,
said installation further comprising
a peripheral fence (2) defining a working area,
a main robot (3), said main robot comprising a body as well as coupling means (34) mobile with respect to said body,
displacement means (37) adapted to displace said main robot, so that it is mobile along at least one direction of said working area,
a set of so-called main operative devices (40 - 46), comprising at least
a starting head grab device (40), provided with means (405, 406) for grabing each starting head,
a brushing device (42), provided with means for brushing at least surface of upper table opposite to said moulds,
a screw device (44), provided with means (45) for screwing/unscrewing each mould with respect to upper table; and
a mould grab device (46), provided with means (464, 466) for grabing each mould,
bearing in mind that said screw device and said mould grab device may form a single combined screw and mould grab device,
each main operative device being provided with complementary coupling means (402, 422, 442, 462) adapted to cooperate with said coupling means of main robot so as to permit a removable attachment between each main operative device and said main robot,
a reception zone (200) for said lower part of said casting table assembly,
a tilting device (6), adapted to move into rotation upper part of said casting table assembly,
control means (9) comprising:
a human machine interface (90),
control lines (95-98) adapted, upon receipt of inputs actuated by an operator, to transmit control orders to at least said main robot (3), said displacement means (37) and each of said operative devices (40 - 46).
[0012] According to one aspect of the invention brushing device (42) comprises a brushing assembly (43) provided with a shaft (431) and at least one brush, adapted to be removably attached on said shaft, advantageously at least two brushes (48, 49) comprising a metallic brush, for example a steel brush, and a plastic brush.
[0013] According to another aspect of the invention screw device (44) is provided with a sensor (455) configured to detect that a predetermined so-called maximum torque has been applied to removable attachment means (13), said sensor being also configured to send an alarm to said control means if said predetermined maximum torque has not been detected.
[0014] According to still another aspect of the invention tilting device comprises two fixed bases as well as two mobile flanges, each base and each flange being equipped with complementary drive means, each flange comprises clamping means, so as to firmly maintain body of upper table with respect to said flange, said tilting device comprising also safety bridges (68) each adapted to cooperate with a respective flange.
[0015] According to still another aspect of the invention starting head grab device (40) comprises a body (400), claws mobile with respect to said body between a grab configuration and a release configuration, as well as at least one finger mobile with respect to said body between an inactive configuration and an active configuration for unlocking said locking means.
[0016] According to still another aspect of the invention said installation comprises a so-called auxiliary robot (7), said auxiliary robot (7) comprising a body as well as a cleaning device adapted to clean starting head.
[0017] According to an advantageous feature said installation may comprise at least one cleaning station (82, 83), comprising holding means for holding said starting head, said installation comprising also a so-called auxiliary cleaning robot (7) provided with cleaning means for cleaning said starting head.
[0018] According to a further advantageous feature said robot may comprise at least one intermediate arm, mobile with respect to body, said arm supporting said coupling means.
[0019] According to still another aspect of the invention mould grab device (46) comprises jaws (464, 466) mobile between a grab configuration and a release configuration of said mould.
[0020] According to an advantageous feature starting head grab comprises a mobile scrapping member, mobile with respect to said body.
[0021] According to still another aspect of the invention said brush is located in a so-called suction volume, brushing device being provided with fittings adapted to cooperate with a suction system.
[0022] According to an advantageous feature of the invention at least one and in particular several stands are provided, each for a respective main device, each stand comprising detector adapted to detect the presence of one given device on its stand.
[0023] According to another aspect of the invention said installation comprises a so-called scrapping station, comprising a fixed scrapping member.
[0024] According to another aspect of the invention peripheral fence defines a substantially closed working area, said fence defining at least one aperture for entrance and exit in particular of a trolley intended to support moulds.
[0025] A second object of the invention is an automated maintenance method of a casting table assembly, said casting table assembly comprising
an upper part, also called upper table (10), said upper table comprising a rectangular frame (100), a plurality of openings (110) provided in the frame, a plurality of moulds (12), each facing a respective opening, and removable attachment means (13) making it possible to attach said moulds with respect to said frame,
a lower part, also called lower table (15), said lower table (15) comprising a body (150), a plurality of so-called starting heads (18), each being intended to be inserted into a respective mould, and locking means (19) making it possible to lock said starting heads with respect to said body,
said method comprising, under control of control means (9),
placing said lower table on said reception zone,
engaging said upper table on said tilting device,
removing at least one, in particular a majority of starting heads, via starting head grab device (40), cleaning said starting heads and placing back said cleaned starting heads in their initial location,
brushing at least surface of upper table opposite to said moulds via said brushing device (42),
removing at least one, in particular a majority of moulds, via said screw device (44) and said mould grab device (46), and driving said moulds to a repair area.
[0026] According to an advantageous feature of this maintenance method:
some first parts of upper table, in particular cover (114) and protrusions (115) protruding out of said cover, are cleaned with the metallic brush; and
some second parts of upper table, in particular roads (111), corners (112) and holes (113) are cleaned with the metallic brush the plastic brush.
[0027] According to a further advantageous aspect of the invention metallic brush is given a first so called cleaning height (H1) to clean first protrusions (115), and a second so called cleaning height (H2) to clean then cover (114).
[0028] According to still another aspect of the invention the instantaneous wear of metallic brush is determined and a warning message is sent, if the instantaneous magnitude of said wear is superior to a predefined value.
[0029] According to an advantageous feature, said method comprises determining the instantaneous wear of metallic brush comprises moving said brush towards a so-called reference surface, calculating the motion distance and comparing it to a threshold distance.
[0030] According to another aspect of the invention, removing each mould comprises unscrewing said bolts, and unscrewing each bolt first comprises
- engaging said screwing/unscrewing means with said bolts,
- rotating said screwing/unscrewing means in the direction of screwing said bolts and
- if said maximum torque is detected, rotating said screwing/unscrewing means in the direction of unscrewing said bolts.
[0031] According to an advantageous feature of the invention, if said maximum torque is not detected, moving said screwing/unscrewing means laterally with respect to said bolts.
[0032] According to still another advantageous feature of the invention, cleaning said starting head comprises
- moving said starting head, with main robot, towards cleaning station,
- leaving alone said starting head on cleaning station; and
- cleaning starting head on said cleaning station, with auxiliary cleaning robot (7). According to another feature of the invention, engaging said upper table on said tilting device comprises
- moving upper table horizontally towards said first flange until it abuts against clamping means of said first flange,
- moving said second flange until clamping means of said second flange cooperate with said upper table; and
Brief description of figures
[0033]
Figure 1 is a perspective view, showing an upper table and a lower table, which are part of a casting table assembly which is intended to be cleaned according to the invention.
Figure 2 is a perspective view, showing under another angle the upper table of figure 1.
Figure 3 is a schematic perspective view, illustrating the fixation of a mould on said upper table.
Figure 4 is a schematic front view, illustrating the locking of a starting head on said lower table.
Figures 5 and 6 are respectively a top view and a perspective view, showing an installation for the maintenance of said casting table assembly.
Figure 7 is a perspective view, illustrating a main robot which is part of said installation.
Figures 8 and 9 are perspective views, illustrating under different angles a starting head grab which is part of said installation.
Figures 10 and 11 are perspective views, illustrating under different angles a brushing device which is part of said installation.
Figure 12 is a perspective view, illustrating a screw device which is part of said installation.
Figures 13 and 14 are perspective views, illustrating under different angles a mould grab which is part of said installation.
Figure 15 is a perspective view, illustrating a stand adapted for supporting starting head grab of figures 8 and 9.
Figure 16 is a perspective view, illustrating a stand adapted for supporting brushing device according to figures 10 and 11.
Figure 17 is a perspective view, illustrating a fixed frame which belongs to a tilting device, part of said installation.
Figures 18 and 19 are perspective views, illustrating under different angles a mobile flange which belongs to a tilting device part of said installation.
Figure 19a is a perspective view, illustrating the mounting step on above table on the tilting device of figures 17 to 19.
Figure 20 is a perspective view, illustrating at greater scale the final fixing of said upper table on the tilting device of figures 17 to 19.
Figure 21 is a perspective view, illustrating an auxiliary so-called cleaning robot which is part of said installation.
Figure 22 is a perspective view, illustrating a cleaning post, adapted to receive said starting head.
Figure 23 is a perspective view, illustrating a scrapping post, which cooperates with a starting head held by said starting head grab.
Figure 24 is a perspective view, illustrating a trolley for the reception and transportation of moulds.
Figure 25 is a schematic view, illustrating the control means which are part of the installation according to the invention.
Figure 26 is a front view, illustrating extraction of a starting head from lower table, due to starting head grab of figures 8 and 9.
Figure 27 is a perspective view illustrating a cleaning operation of a starting head carried by auxiliary robot of figure 21.
Figure 28 is a schematic view, illustrating the brushing of upper table, due to brushing device of figures 10 and 11.
Figure 28a is a top view, showing at a far greater scale a part of the upper table illustrated in particular on figure 1.
Figure 28b is a schematic view, illustrating the cooperation between two different types of brushes and the brushing device of figure 28.
Figure 28c is a schematic view, illustrating the different cleaning heights given to the metallic brush of figure 28b.
Figure 28d is a schematic view, illustrating the calculation of the wear of the brush of figures 28b and 28c.
Figure 29 is a schematic view, illustrating the unscrewing operation of a mould from the upper table, due to screw device of figure 12.
Figures 29a to 29d are schematic views, illustrating different steps of the unscrewing operation of figure 29.
Figure 30 is a schematic view, illustrating the transportation of the mould of figure 29 from this upper table to a transportation trolley.
Figure 31 is a schematic view, illustrating the forth motion of trolley of figure 30 towards a mould repair area.
Figure 32 is a schematic view, illustrating the back motion of trolley of figure 30 from said repair area.
Figure 33 is a schematic view, illustrating the screwing of a repaired mould on the upper table.
[0034] The following reference numerals are used throughout the present description.
1 casting table assembly - 10 upper table - 100 frame of 10 - 11 trough -110 openings in 11 - 111 roads of 11 - 112 corners of 11 - 113 holes in 11 - 114 cover of 11 - 115 bolts on 114 - 12 moulds - 12a to 12i removed moulds - 12'a to 12'i repaired moulds - 13 screws - 15 lower table - 150 body of 15 - 16 rams - 17 platen - 18 starting head - 19 pin
I installation according to the invention
2 fence - 20 working area - 200 and 201 working zones of 200- 21 posts - 22 grid members - 220 and 221 pivoting members - 210 and 211 posts of 220 and 221 - 23 aperture - 24 barrier - 25 opening
3 main robot - 30 base plate of 3 - 31 body of 30 -32 proximal arm - 33 distal arm - 34 coupling - A31 to A34 rotation axes of 31 to 34 - 35 track - X35 axis of 35 - 36 frame - 37 displacement means
40 starting head grab - 400 body of 40 - 401 centring disc - 402 coupling - 403 404 actuators - 405 406 claws - 408 finger - 41 scrapper assembly - 410 actuator - 411 scrapping rubber
42 brushing device - 420 body of 42 - 422 coupling - 424 bracket - 425 plate - 426 linear bearing - 43 brush assembly - 431 shaft - 433 curtain - 434 top of 433 - 435 suction volume - 436 connectors
44 screw device - 440 body of 44 - 442 coupling - 444 bracket - 45 screwing assembly - 451 screwing tip - 452 socket - d452 distance between 452 and 13 - F452 and f452 opposite rotation directions of 452 - G452 and H452 translation directions of 452 - 455 sensor
46 mould grab - 460 body of 46 - 462 coupling - 463 support - 464 466 jaws - 467 fittings
47 suction pipes - 470 suction system - 475 vacuum system
48 metallic brush - H1 and H2 cleaning heights - 480 free extremity of 48 - Sref reference surface - F48 motion direction of 48 - Dinst instantaneous distance between Sref and 480
49 plastic brush
50 to 56 stands for 40 to 46 - 501 to 561 base chassis - 51 to 57 pedestal - 511 to 571 notch - 512 to 572 support strips - 513, 514 to 573, 574 centring pins
6 tilting device - 60 fixed frames - 61 base plate - 62 support structure - 63 drive - 64 motor - 65 flange - 66 bottom - 661 clamps - 662 studs - 663 pads - 67 rim - 671 drive - 68 safety bridge - 681 projection
7 auxiliary robot - 70 base plate - 71 body - 72 proximal arm - 73 distal arm - 74 cleaning device - A71 to A74 rotation axes of 71 to 74
80 scrapping station - 802 base structure - 804 scrapping member - 806 notch 82, 83 cleaning stations - 820 post - 822 gripper - 823 top support
84 grease station - 840 tank - 842 distributor
85 trolley - 850 base structure - 852 top carpet - 854 identification camera - 86 auxiliary device - 860 further camera
9 control means - 90 computer - 91 to 94 information lines - 940 reading camera - 95 to 98 control lines - 99 detection system
Detailed description of the invention
[0035] The present invention deals with the maintenance and, in particular, with the cleaning of a casting table assembly. This assembly is shown on figures 1 and 2, where it is referenced 1 as a whole. This assembly, which is known as such and is not part of the invention, will be now briefly described.
[0036] Said casting table assembly 1 comprises first an upper part, also called upper table 10. This upper table is also called fixed, since it does not move in use with respect to the casting pit. Said upper table 10 mainly comprises a rectangular frame 100, as well as a trough 11 provided on the upper part of this frame. Said trough defines a plurality of openings 110, whereas a corresponding number of moulds 12 are provided on the lower part of the frame (see in particular figure 2). Each mould 12 is attached on the lower face 101 of frame 100 by way of appropriate attachment means: removable means are preferred, in particular screws which are schematically illustrated and referenced 13 on figure 3. Typically four screws are provided, for the attachment of each mould on the frame.
[0037] Said casting table assembly 1 also comprises a lower part, also called lower table 15. This upper table is also called mobile, since it moves in use with respect to the casting pit, typically along a vertical axis. Said lower table 15 mainly comprises a rectangular body 150, the dimensions of which are similar to those of frame 100. Said body 150 is provided with a plurality of rams 16, each supporting a respective platen 17. Moreover, lower table comprises a plurality of so-called starting heads 18, which are inserted within the moulds of the fixed table at the beginning of the casting. Then, once the aluminium in the moulds starts to solidify, the mobile table starts going down gradually by creating the billet.
[0038] Each starting head 18 is attached on a respective platen 17, by way of locking means. In a typical way, as shown on figure 4, a pin 19 held by said starting head cooperates with a housing of said platen. In a way known as such, in use, each starting head 18 is inserted within a respective mould of the fixed table at the beginning of the casting. Then, once the aluminum in the moulds starts to solidify, the mobile table starts going down gradually by creating a billet.
[0039] Figures 5 and 6 show a general view of an installation according to the invention, referenced I as a whole. it essentially comprises a peripheral fence 2, a first or main robot 3, a set 40 to 46 of main devices adapted to cooperate with robot 3, a set 50 to 56 of stands for main devices, a tilting device 6, a second or auxiliary robot 7, a set of accessory stations, as well as control means 9.
[0040] Peripheral fence 2, which is rectangular shaped, defines an inside working area 20. This fence comprises a plurality of horizontal posts 21, which support grid members 22. One permanent aperture 23 is provided in the grid members so as to permit entrance of a transportation trolley, amongst others. The motions across said aperture are monitored by an optical barrier 24, of any appropriate type. Moreover, two adjacent grid members 220 and 221 are pivotally mounted on their posts 210 and 211, so as to define a provisional opening 25.
[0041] As can be seen at a greater scale on figure 7, main robot 3 comprises a base plate 30, which is attached to a track 35. The latter defines a main axis X35, so as to delimit two working zones 200 and 201 of working area 20, respectively on the top and on the bottom of figure 5. Track 35 rests on a frame 36, so as to be located above the ground. Motion of base plate 30 with respect to tracks 35, along axis X35, is ensured by appropriate displacement means, which are schematically illustrated on figure 7. The latter, which are not part of the invention, will not be described in further details.
[0042] Said base plate 30 supports a body 31 which is adapted to rotate around the substantially vertical axis A31, with respect to said base plate. A proximal arm 32 is mounted on said body 31, while being adapted to rotate with respect to the latter, around an axis A32. Moreover, a distal arm 33 is mounted on said arm 32, while being adapted to rotate with respect to the latter, around an axis A33. Said arm 33 is provided with an appropriate coupling 34, which makes it possible to handle each device of the set 4. Moreover, said coupling 34 is adapted to rotate with respect to arm around axis A34, to enable the tilting of main device fixed on said coupling.
[0043] Set of main devices comprise a so-called starting head grab 40, a brushing device 42, a screw device 44 and a so-called mould grab 46. Each of these devices is adapted to rest, in use, on respective stands 50, 52, 54 and 56.
[0044] With reference to figures 8 and 9, starting head grab device 40 comprises first a body 400, which supports a centring disc 401 upon which rests a so-called complementary coupling 402. The latter is adapted to cooperate with above-mentioned coupling 34, provided on main robot 3. The locking and unlocking of these quick type couplings 34 and 402 can be achieved by any appropriate means, such as non-represented pneumatic means.
[0045] On opposite sides of body 400, grab device 40 is equipped with actuators 403, 404, in particular of the pneumatic type, adapted to displace claws 405, 406 the one with respect to each other. As will be further described, these claws are intended to grasp a starting head 18 out of body 150 of lower table 15. One 405 of above claws supports a finger 408, which is adapted to unlock connecting means 19. Moreover, a scrapper assembly 41 is fixed on body 400 by any appropriate means, in particular screwing. Said assembly 41 comprises an actuator 410, for example of pneumatic type, which is adapted to move a so-called scrapping rubber 411.
[0046] As shown on figures 10 and 11 brushing device 42 comprises first a body 420, which supports a complementary coupling 422, analogous to the above described one 402. These couplings 402 and 442 are of any appropriate type, known as such. The body is attached, via a bracket 424, to a support plate 425 which support a brush assembly 43. The plate 425 is mobile with respect to bracket 424, thanks to any appropriate means such as a linear bearing 426.
[0047] Brush assembly comprises a shaft 431 which is driven in rotation by any appropriate means. This shaft supports, at its lower end, a metallic brush 48. In an advantageous way, the fixation between shaft and brush is of the removable type, so that several kinds of brushes may be adapted for a better operation. Said shaft is adapted to cooperate with two kinds of brushes, in particular said metallic brush and a brush 49 made of plastic material. The natures of these respective metallic and plastic brushes are known as such. The brush assembly 43 is surrounded by a peripheral protection curtain 433, for example made of rubber.
[0048] This curtain, which is provided with a top 434 attached to plate 425 but which is opened at its bottom, defines a cylindrical so-called suction volume 435. So as to carry out suction operation, said top 434 is equipped with connectors 436, adapted to cooperate with suction pipes 47 that are illustrated in dotted lines on figure 5. Said pipes can be plugged on a suction system 470, located outside fence 2.
[0049] With reference to figure 12 screw device 44 comprises first a body 440, which supports a complementary coupling 442, analogous to the above described one 402. The body is attached to a bracket 444, which supports a screwing assembly 45 which is adapted to cooperate with the fixation screws of the moulds. This screwing assembly comprises in particular a screwing tip 451 configured to screw or unscrew said fixation screws. There is also provided a socket 452, of any known type.
[0050] As shown on figures 13 and 14 mould grab device 46 comprises first a body 460, which supports a complementary coupling 462, analogous to the above described one 402. Body 460 is attached to a support 463, which holds two jaws 464 and 466. The latter are mobile as the one with respect to the other, along axis X462, between a first position wherein they are adapted to grab one mould, and a release position of this mould. Motion is ensured in a pneumatic way, due to fittings 47 capable of cooperating with a not represented pipe.
[0051] In the illustrated embodiment, screw device 44 is separated from mould grab device 46. According to a not shown variant, these devices may be gathered to form a so-called single combined device, ensuring both screwing/unscrewing function as well as mould grab function. In this respect this combined device comprises a single body, supporting both screwing assembly as well as grab jaws.
[0052] Figures 15 and 16 illustrate stands 50 to 56 adapted to cooperate with above described devices 40 to 46. Stands 52 to 56 of figure 16 are analogous, whereas stand 50 of figure 16 is slightly different while having globally the same structure. Indeed, each of these stands comprises first a base chassis 501 to 561 of any appropriate type, upon which rests a pedestal 51 to 57. The latter, which is provided with a central notch 511 to 571, defines two opposite support strips 512 to 572 each equipped with centring pins 513, 514 to 573, 574. The latter cooperate in use with guides, such as the ones 413 to 473 provided on the lower face of body 400 to 460.
[0053] Moreover, each strip 512 to 572 is also equipped with support fingers 515, 516 to 575, 576, which cooperate in use of with washers such as the one 414 provided on the lower face of body 400 to 460. Strips are also equipped with a presence sensor 517 to 577, which makes it possible to confirm device 40 to 46 is actually on its stand 50 to 56. When device 40 to 46 rests on its stand, the notch 511 to 571 allows a free passage under pedestal 51 to 57, for some structural members of said device, such as claws 405, 406 of grab 40. The shape and size of some mechanical components may vary from one stand to another, bearing in mind that the functions of these components are substantially the same for each stand.
[0054] Tilting device 6 comprises two external fixed frames 60 shown on figure 17, cooperating with respective internal mobile flanges 65 illustrated on figures 18 and 19. Frame 60 is first provided with a base plate 61, as well as a tubular support structure 62. The latter holds a slewing drive 63, driven itself by a motor 64 of any appropriate type. Flange 65 comprises first a bottom 66 which is provided (see figure 19a) with fixation clamps 661, centring studs 662 as well as resting pads 663.
[0055] On a first side of bottom 16 there is provision of a rim 67, which is equipped with a complementary drive 671, adapted to cooperate with drive 63 so as to ensure the motion of the whole flange. On the other side bottom 66 is adapted to cooperate with a safety bridge 68, which is provided with a median U shaped projection 681. The implementation of this tilting device will be described hereafter.
[0056] As shown on figure 21 auxiliary robot 7, also called cleaning robot, comprises a base plate 70 which rests in a fixed manner on working zone 200. Said base plate 70 supports a body 71 which is adapted to rotate around the substantially vertical axis A71, with respect to said base plate. A proximal arm 72 is mounted on said body 71, while being adapted to rotate with respect to the latter, around an axis A72. Moreover, a distal arm 73 is mounted on said arm 72, while being adapted to rotate with respect to the latter, around an axis A73. Said distal arm 73 is provided with a cleaning device 74, adapted to rotate with respect to arm 73 around axis A74.
[0057] Accessory stations first comprise one scrapping station 80, shown on figure 23, which is equipped with a base structure 802, supporting a so-called fixed scrapping member 804 typically made of rubber. This member 804 is provided with a central notch 806, adapted to cooperate with the bottom of the starting head during operation, so as to precisely position this starting head.
[0058] Moreover, there are two identical cleaning stations 82 and 83, shown on figure 22. With reference to figure 22 each station, such as the one 82, comprises a post 820 which supports a pneumatic gripper 822. The latter makes it possible to firmly hold the starting head during the process, by way of a top support 823. Moreover, this station 82 is equipped with a not shown sensor, for detecting the starting when arriving on said station.
[0059] Furthermore, a grease station 84 is provided, which is schematically represented on figure 5. This station comprises a tank 840, a not shown pump as well as a grease distributor 842.
[0060] A so-called mould trolley 85, shown on figure 2 as well on figure 31 at a greater scale, is provided close to the main aperture. This trolley comprises a mobile base structure 850, as well as a top carpet 852 for the reception of some moulds. This trolley is associated with an identification camera 854, of the artificial intelligence type, the function of which will be further detailed.
[0061] In addition, close to trolley 85, an auxiliary device 86 makes it possible to check the correct centring of the moulds. In this respect it comprises a further camera 860, of the optical character recognition, the function of which will also be further detailed.
[0062] Control means 9, shown on figure 25, comprise first a human machine interface, in the form of a computer 90 intended to receive inputs from an operator. Said computer is associated with Programmable Logic Controller (or PLC), with a motor control center (or MCC) as well as with artificial vision device.
[0063] Control means also comprise a plurality of so-called information lines, which connect the above-mentioned computer 90 with structural members of the installation. A first information line 91 connects computer with detectors, provided on the table assembly. Two further information lines 92 and 93 connect computer with detectors, provided on each cleaning station 82 and 83. Another information line 94 connects computer with a reading device adapted to read an identification code. Said reading device may be a camera 940 of any appropriate type, not shown in detail on the figures.
[0064] Control means comprise in addition a plurality of so-called control lines, which connect computer 90 with some others structural members of the installation. A first control line 95 connects computer with motor means, adapted to drive the main robot 3. Another control line 96 connects computer with specific motor means, adapted to drive the auxiliary robot 7. Still another control line 97 connects computer with specific motor means, adapted to drive tilting device 6. A further control line 98 connects computer with vacuum system 475. The above control lines 95 to 98 are configured to control respectively robots 3 and 7, tilting device 6 and vacuum system 475, upon inputs from an operator on computer 90.
[0065] An implementation of the above installation, according to the invention, will now be described.
[0066] The casting table assembly 1 is first collected from a not illustrated cast house shop floor and is inspected visually for possible damage. This step is carried out by an operator. In a second step, the casting table assembly is fixed in a not shown lifting hook; this is typically a manual operation.
[0067] The type and size of the casting table assembly 1 are then selected. This can be carried out by an operator on the computer or can be carried out automatically by above mentioned camera 940 reading the unique identification code of the casting table assembly, or by the detectors provided on the table assembly. Information line 91 transmits appropriate information from the detector or camera to the computer. This step is not illustrated on the figures.
[0068] The bottom part 15 of the casting table assembly 1 is then placed on first working zone 200, whereas the upper part 10 is mounted on the tilting device located on other working zone 201. To this end these two parts are first separated the one from the other using an overhead crane, which is typically done by an operator and is not shown on the figures. The mounting of upper part on device 6 is carried out using an overhead crane, which is typically done by an operator. Said upper part is also properly secured to tilting device 6 which is supervised by an operator. If the tilting station is busy, then the upper part 10 is stored elsewhere (typically on the floor).
[0069] With reference to figures 19a and 20, let us detail and now the mounting of upper part 11 on tilting device 6. Upper table 11 is moved horizontally towards first flange 65a according to arrow F11, using a not shown crane, until its front face abuts both clamps 661 and studs 662, while resting upon pads 663. Then not shown other flange 65b is moved also horizontally according to arrow F65b until its clamps studs and pads cooperate with opposite front face of table 11. Finally, each bridge 68 is lowered according to arrow F68, also using said crane, so as to firmly lock table with respect to both flanges.
[0070] In final use, as can be seen on figure 20, opposite ends 101 of rectangular frame 100 extend through the passage 69 defined by bottom 66 and bridge 68. In particular the tips 112 of table 11 extend through projection 681.
[0071] A first specific aspect of the implementation is the maintenance of starting heads 18. To this end, starting heads that need to be cleaned are first selected. As will be explained, the invention allows flexibility by giving the option of selecting if all the starting heads are to be cleaned or just a selection made by the operator. The layout of the starting heads is shown on the computer and the operator can select the starting heads to be cleaned. If required, the cleaning of all the heads can be selected as well.
[0072] When the desired starting heads are validated, a corresponding order is transferred to robot 7 via control line 96, so as to start cleaning process of said starting heads. The robot first moves towards stand 50, upon which rests starting head grab 40. Coupling of robot 3 engages with complementary coupling of grab 40 so that robot 3 and grab 40 are adapted to mutually cooperate. Said robot, now provided with grab 40, moves to the position of the starting head that has to be removed. As shown on figure 26, which does not illustrate the robot itself, once above the head the robots goes down with the grab according to arrow F40.
[0073] The finger 408 is moved along arrow F408, so as to push up the releasing pin 19 of the starting head. Then the actuator 403 moves the respective claw along arrow F405, so as to put off-center the starting head from its support platen 17. In an advantageous way a not shown mechanical stopper is adapted to limit the stroke of this actuator so that the starting head puts off-center just the required distance from the lower table. This allows the robot to lift the starting head without obstruction when required.
[0074] Then the other actuator 404 grabs the starting head 18, using the other claw 406. Then robot 3 takes out this starting head of the lower table 15 and moves upwards so that mobile grease scrapper 411 extends downwards from the grab along arrow F411. This scrapper cleans the facing surfaces of the platen 17, typically with two passes.
[0075] Main robot 3, provided with the starting head 18, moves towards scrapping station 80. First of all, the bottom of the starting head is cleaned from grease on the fixed scrapping member 804. Once done, the grease scrapper 411 of the grab 40 is cleaned as well on this fixed scrapping member 804.
[0076] Once this grease scrapping operation has been carried out, robot 3 provided with starting head 18 moves towards the cleaning stations 82 and 83. Information concerning the availability of each station is given to the operator, via lines 92 and 93. This operator controls then robot 3 via line 95, so that said robot approaches one available cleaning station. By releasing the actuators, robot 3 leaves alone the head 18 on the cleaning station, such as the one 82. At the same moment, the pneumatic gripper 822 of the cleaning post is actuated along arrow F822, so that the starting head is firmly held on top support 823 as shown on figure 27. The robot 3 provided with the starting head grab 40 can now head to another task.
[0077] Now the cleaning robot 7 starts to clean the top of the starting head 18 with its metallic brush 74, as shown on figure 27. Said cleaning step is operated circularly from the outer circle up to the center, by making concentric circles. The brushing finishes when it cleans even the external diameter part of the starting head.
[0078] Once cleaned by brush 74, the starting head 18 is picked up by the main robot 3 from the cleaning post 82. Robot 3 and grab 40, the latter holding head 18, move to the greasing station 84, where grease is applied to the bottom of the starting head, by turning the starting head upside down. The main robot 3 then takes the starting head 18 and returns it back to the position it was taken before on the lower table 15, making the same backwards process.
[0079] Another specific aspect of the implementation is the maintenance of upper table 10 as well as of moulds 12 held by this table. In this respect upper table is tilted with tilting device 6 for example by 75°, to allow access to its bottom side. Said table 10 is then properly identified in the computer system using its identification code, which is typicaly marked on a label affixed to the table; this identification can be done for example by reading the idenfication code on said label using reading camera 940, and then transmitted to computer 90. This identification can also be carried out manually entering the identification code into the computer system using the Human-Machine-Interface (HMI).
[0080] The top side of the upper table is then cleaned. To this end, said top side is first visually inspected by the operator, start up dam holders are removed, and any solidified aluminium that may stick on the table is removed; any damaged refractories are replaced.
[0081] In a further step the cleaning operation to be carried out by the robot is determined and defined; this is typically done by the operator and entered into the computer system using the HMI. Certain parameters necessary for the cleaning operation are determined and entered or validated; this is typically done by the operator and entered into the computer system using the HMI.
[0082] More precisely, the type and size of the table has to be selected on the HMI. Appropriate detectors may be provided on the tables to ensure the selected table is the right one. Moreover, the system is configured such that the layout of the brushing areas can be selected on the HMI. This allows flexibility, as it may not be sensible to clean areas that do not require cleaning.
[0083] In still a further step, the vacuum system 475 is actuated by control line 98 and the main robot 3 is actuated by control line 95. Under these circumstances robot 3 heads to stand 52, so as to engage and to pick up brush device 42. The pre-programmed cleaning cycle is then carried out, as illustrated on figure 28, and may include spraying small quantities of water on the top plates to minimize formation of dust. Grinding on the top plates is performed by the robot using steel brush attachments.
[0084] According to an advantageous feature of the invention, brushing step is operated according to several manners, throughout the upper side of upper table 10. In a way known as such, with reference to figure 28a, said upper side may be divided into different zones.
[0085] Trough 11 forms branches, which define so called roads 111, corners 112 and holes 113. Roads 111 are the main parts, from where the metal is distributed into every opening 110. Corners 112 are formed by the areas connecting the roads with the holes surrounding the openings 111: they typically have the shape of a truncated cone, with their smaller face at the bottom, close to the hole. Finally, the holes 113 are provided at the periphery of each opening 110: they connect the table 10 with the starting heads and the billet ingot.
[0086] Apart from said trough 11, said upper side delimits a so-called cover 114. In a way known as such, this cover is provided with some protrusions, due in particular to the presence of bolts 115 (schematically representated on figure 28a but also illustrated on figure 1).
[0087] According to an advantageous embodiment of the invention, covers 114 are brushed with metallic brush whereas both roads, corners and holes are treated with plastic brush. Due to the importance of the nature of the brushes, the installation is provided with a detection system 99 which is adapted to determine which brush is actually mounted on brushing shaft 431. In this respect figure 28b schematically illustrates brushing shaft 431, metallic brush 48, plastic brush 49 and detection system 99. In case the appropriate brush is not engaged on shaft, detection system is adapted to give appropriate information to control means 9, which in turn warns the operator to change the brush.
[0088] The brushing of the covers 114 starts by cleaning first the protrusions 115: to this end, a first so-called cleaning height H1 is given to the brush by the control means. Said height corresponds to the distance between the free extremity 480 of brush 48 and the facing wall of the shaft 431. Once protrusions are cleaned, a second cleaning height H2 so as to clean the rest of cover 114. Providing these two different heights H1 and H2, which are schematically represented on figure 28c, is advantageous: indeed, if the same cleaning height is set for the whole cover, it will result in collisions with the protrusions. These collisions are likely to create vibrations and improper movements, causing the decrease of the performance. In addition, the brushing motor may be advantageously provided with a not shown sensor: in case the latter detects an increase in the torque value, the motor stops and an alarm is raised.
[0089] According to a particularly advantageous feature of the invention, wear of brushes are periodically identified. Indeed, said wear is of high importance for the proper processing of the method according to the invention. Figure 28d illustrates the so-called instantaneous working distance, namely the distance along vertical axis between the free extremity 480 of brush 48 and a reference horizontal surface Sref, which typically corresponds to the table platten. This distance is measured by moving brush 48 along arrow F48, and it contacts with reference surface Sref. If instantaneous distance Dinst is superior to a threshold value Dthr, it means that brush has undergone a significant wear and therefore needs to be changed. Indeed, this worn brush is not adapted any more to carry out an efficient brushing operation.
[0090] Said wear calculation is advantageously processed at the beginning of the cycle and thereafter periodically, for example every two areas brushed.
[0091] When the cleaning cycle as pre-programmed is completed, the robot will return to its home position to facilitate inspection of the part. The surface of the top side of upper table, which has been submitted to cleaning process, is thereafter inspected, by a camera and/or by an operator. If it decided that, if said surface has not been properly cleaned, further cleaning is programmed, using appropriate parameters; these parameters may be entered by the operator using the HMI. When the last cleaning cycle is finished, the main robot 3 will move to its home position.
[0092] Then the moulds 12 which require removing are identified and designated; this can be done by the operator who inspects the moulds and enters instructions to the robot 3 into the HMI, via control line 95. The table 10 is turned of 180° according to arrow f10 on figure 29, so that the moulds are now located above the table for easy access of the robot. The robot 3 heads to stand 54, so as to engage with and grasp screw device 44. Robot provided with screw device moves then towards the table in order to unscrew the bolts 13 from each designated mould on the casting table, in particular the one 12a on figure 29.
[0093] In a more detailed way, with reference to figure 29a, robot 3 heads to the first mould to be removed, directly above the first bolt to be unscrewed. When distance d452 between socket 452 and said first bolt reaches a given value, for example 50 mm, socket is driven to rotate in a direction F452 to tighten the bolt, typically clockwise. Socket is then approached until it engages with the bolt 13 (figure 29b) and, since this bolt is already tightened, a predetermined so-called maximum value of torque is applied. According to an advantageous feature of the invention, screw device 44 is provided with a schematically illustrated sensor 455, which is adapted to detect the occurrence of said maximum torque. Once sensor 455 has sent an information in connection with this occurrence, socket is driven to rotate in an opposite direction f452 to unscrew the bolt, typically counter-clockwise (figure 29c). This rotation is carried out during a predetermined duration, for example 13 seconds. It is preferred that the unscrewed bolt stays always in the mould, no matter the time it is unscrewed.
[0094] If sensor 455 does not send an information concerning the occurrence of maximum torque, it means that socket does not engage the bolt. In this case socket is first displaced laterally with respect to said mould (see figure 29d), along the two double arrows G452 and H452. if still no detection is received after this first cycle, socket is moved away from the bolt, is displaced laterally with respect to said mould and is once again moved toward the mould, until maximum torque is detected. After this second cycle, if no signal of maximum torque is received, control means 9 acknowledge that operation has not been successfully carried out, thus raising an appropriate alarm.
[0095] In a further step the robot 3 disengages with screw device 44, so as to place it back on its stand 54 (not shown operation). Said robot heads then to stand 56, so as to engage with mould grab 46. Robot provided with grab 46 moves then to the table, so to remove the designated moulds, which have been previously unscrewed. Robot heads then to trolley 85, so as to transport the designated moulds on top of this trolley.
[0096] The different moulds are then placed in a given order on the transportation trolley 85, as shown on figure 30. When the last designated mould has been removed, the robot will move to its home position. The removed moulds 12a to 12i on figure 31 are then moved through aperture 23, along arrow F85. These moulds are driven to a mould repair area 1000, of any appropriate type, for maintenance. After this step, the repaired moulds 12'a to 12'i are posed back on trolley 85, and then reintroduced into working area, along arrow F'85 as seen on figure 32.
[0097] Thereafter camera 860 checks the identification digit of each repaired mould 12'a to 12'i, as shown on figure 32. Finally, as shown on figure 33, the robot grasps each repaired mould and screws them back in their initial location on the table. In a more detailed way, the same way as explained with reference to figure 29a, robot 3 heads to the first mould to be attached, directly above the first bolt to be screwed. When distance d452 between socket 452 and said first bolt reaches a given value, socket is driven to rotate until it engages with the bolt 13 (like in figure 29b). When sensor 455 detects that maximum torque is applied, the screwing operation is considered fulfilled and robot processes next bolt.
[0098] If sensor 455 does not send an information concerning the occurrence of maximum torque, it means that socket does not engage the first bolt to be screwed. In this case, socket is first displaced laterally with respect to said mould (like in figure 29d). If still no detection is received after this first cycle, socket is moved away from the bolt, is displaced laterally with respect to said mould and is once again moved toward the mould, until maximum torque is detected. After this second cycle, if no signal of maximum torque is received, control means 9 acknowledge that operation has not been successfully carried out, thus raising an appropriate alarm.
[0099] The invention brings about several advantages with respect to the prior art cleaning and maintenance of casting table assembly. As explained above, prior art processes are essentially based on manual operations. The installation and method according to the invention enable the user to facilitate the maintenance of casting tables, moulds and mould components such as starting heads.
[0100] As mentionned several times throughout this description, it is highly desirable to individually indentify certain components, i.e. to allocate a unique identification code to all parts of certain types of components. This applies in particular to the table 10 and to the moulds 12. Said identification code can be of any suitable type, such as a bar code, a QR code, an alphanumerical code, and it can be of any suitable kind, such as an engraved code (for example by laser engraving), or an affixed label printed on a suitably heat-resistant material. It can be read by any suitable reading device, such as a camera liked to a suitably configured computing device executing a suitably configured identification software. It is highly adavantageous to be able to keep track of each component bearing a unique identification code, both for the sake of localisation of the component within the workshop and for the sake of tracking it history of use. Concerning the history of use, the unique identification of a component such as a mold may allow to relate its state and maintenance history to the slow emergence of deviations in product quality (such as surface quality) of the cast ingots or billets.
an upper part, also called upper table (10), said upper table comprising a rectangular frame (100), a plurality of openings (110) provided in the frame, a plurality of moulds (12), each facing a respective opening, and removable attachment means (13), in particular bolts, making it possible to attach said moulds with respect to said frame,
a lower part, also called lower table (15), said lower table (15) comprising a body (150), a plurality of so-called starting heads (18), each being intended to be inserted into a respective mould, and locking means (19) making it possible to lock said starting heads with respect to said body,
said installation (I) comprising
a peripheral fence (2) defining a working area,
a main robot (3), said main robot comprising a body as well as coupling means (34) mobile with respect to said body,
displacement means (37) adapted to displace said main robot, so that it is mobile along at least one direction of said working area,
a set of so-called main operative devices (40 - 46), comprising at least
a starting head grab device (40), provided with means (405, 406) for grabing each starting head,
a brushing device (42), provided with means for brushing at least surface of upper table opposite to said moulds,
a screw device (44), provided with means (45) for screwing/unscrewing each mould with respect to upper table; and
a mould grab device (46), provided with means (464, 466) for grabing each mould,
bearing in mind that said screw device and said mould grab device may form a single combined screw and mould grab device,
each main operative device being provided with complementary coupling means (402, 422, 442, 462) adapted to cooperate with said coupling means of main robot so as to permit a removable attachment between each main operative device and said main robot,
a reception zone (200) for said lower part of said casting table assembly,
a tilting device (6), adapted to move into rotation upper part of said casting table
assembly, control means (9) comprising:
a human machine interface (90),
control lines (95-98) adapted, upon receipt of inputs actuated by an operator, to transmit control orders to at least said main robot (3), said displacement means (37) and each of said operative devices (40 - 46).
an upper part, also called upper table (10), said upper table comprising a rectangular frame (100), a plurality of openings (110) provided in the frame, a plurality of moulds (12), each facing a respective opening, and removable attachment means (13) making it possible to attach said moulds with respect to said frame,
a lower part, also called lower table (15), said lower table (15) comprising a body (150), a plurality of so-called starting heads (18), each being intended to be inserted into a respective mould, and locking means (19) making it possible to lock said starting heads with respect to said body,
said method comprising, under control of control means (9),
placing said lower table on said reception zone,
engaging said upper table on said tilting device,
removing at least one, in particular a majority of starting heads, via starting head grab device (40), cleaning said starting heads and placing back said cleaned starting heads in their initial location,
brushing at least surface of upper table opposite to said moulds via said brushing device (42),
removing at least one, in particular a majority of moulds, via said screw device (44) and said mould grab device (46) and driving said moulds to a repair area.
some first parts of upper table, in particular cover (114) and protrusions (115) protruding out of said cover, are cleaned with the metallic brush; and
some second parts of upper table, in particular roads (111), corners (112) and holes (113) are cleaned with the metallic brush the plastic brush.
- engaging said screwing/unscrewing means with said bolts,
- rotating said screwing/unscrewing means in the direction of screwing said bolts and
- if said maximum torque is detected, rotating said screwing/unscrewing means in the direction of unscrewing said bolts.
- moving said starting head, with main robot, towards cleaning station,
- leaving alone said starting head on cleaning station; and
- cleaning starting head on said cleaning station, with auxiliary cleaning robot (7).
- moving upper table horizontally towards said first flange until it abuts against clamping means of said first flange,
- moving said second flange until clamping means of said second flange cooperate with said upper table; and
positioning each safety bridge close to each flange.REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description