Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B41/00—Component parts such as frames, beds, carriages, headstocks
  • B24B41/06—Work supports, e.g. adjustable steadies
  • B24B41/061—Work supports, e.g. adjustable steadies axially supporting turning workpieces, e.g. magnetically, pneumatically
  • B24B41/062—Work supports, e.g. adjustable steadies axially supporting turning workpieces, e.g. magnetically, pneumatically between centres; Dogs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B41/00—Component parts such as frames, beds, carriages, headstocks
  • B24B41/06—Work supports, e.g. adjustable steadies
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B41/00—Component parts such as frames, beds, carriages, headstocks
  • B24B41/06—Work supports, e.g. adjustable steadies
  • B24B41/065—Steady rests
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B5/00—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor
  • B24B5/02—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor involving centres or chucks for holding work
  • B24B5/04—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor involving centres or chucks for holding work for grinding cylindrical surfaces externally

Definitions

• the present invention relates to a method for the positioning of operative cylinders on a grinding machine and a grinding machine which implements this method; it should be pointed out that the definition "operative cylinders" refers, for example, to cylinders of rolling mills for the rolling of metals, those used in paper- mills, those used in oil-pressure applications, shafts of marine motors and in general all cylinders made of metallic and non-metallic materials which are of industrial interest .
• the latter in fact, have dimensions varying from 40 mm to 2,300 mm in diameter, 1,000 mm to 12,000 mm in length and weights ranging from a few tens of daN up to 230-250 t.
• the grinding of a cylinder must always be preceded by a preliminary positioning phase of the latter on the machine, which is effected by inserting the cylinder to be ground between a piece-holder head and a tailstock centre and subsequently supporting it between centres of the machine and, if necessary, tightening it with one or more lunettes or contrast devices, or resting the cylinder itself directly on a pair of supporting lunettes; either of the two solutions is selected in relation to the type of cylinder to be ground and the processing to be effected.
• the known art envisages that the cylinder to be ground is first loaded onto the grinding machine with a loading device (such as, for example, a gantry crane, a jib crane or an automatic loading device) , it is then moved until one of its ends is supported by the centre of the piece- holder head, the tailstock centre is then moved until the contact with this supports the opposite end of the cylinder, and finally the lunettes or contrast devices are moved along the cylinder, so as to position them correctly with respect to the part of the cylinder to be ground.
• a loading device such as, for example, a gantry crane, a jib crane or an automatic loading device
• the lunettes or contrast devices are normally produced as supports suitable for opposing the thrusts that the grinding wheel exerts on the piece being processed; they are normally positioned at regular distances along the cylinder, in order to uniformly oppose the forces during the grinding process .
• set-up can be manual or automatic.
• set-up time is extremely important as a series of various operations are required, which must be accurately effected in order to verify their correctness.
• Another drawback linked to the known art relates to the fact that during the loading, the cylinder must be moved in three directions and in particular, among these, also along the longitudinal axis, in order to be correctly positioned on the grinding machine; these regulation movements require the use of a loading device.
• this device is typically a gantry crane or a jib crane and the precision with which the cylinder must be moved and positioned requires long positioning times, skilled operators and the risk that, with an erroneous manoeuvre, the cylinder, or machine, or both, can be damaged.
• the movement of the cylinders is effected with 3 -axis loading systems and if, on the one hand, they reduce the manoeuvring times and increase the safety of the same, on the other, they require ma- chines which move the load along 3 axes and are consequently, by nature, complex, costly and require maintenance.
• the positioning of the lunettes and tailstock centre is also quite lengthy with the traditional technology, in the sense that they must be moved along the cy- linder to be correctly positioned, care being taken to measure the distances from the side of the cylinder associated with the piece-holder head.
• the manual solution is economical, on the other, it requires time and accuracy on the part of the operator, whereas although the automatic solution guarantees operational velocity and precision, it requires a movement and control mechanism for the tailstock centre and for each of the lunettes.
• the general objective of the present invention is consequently to overcome these and other drawbacks of the known art .
• a positioning method has been conceived for these cylinders which envisages at least the following steps:
• the movement of the piece-holder head and tailstock centre is preferably of the same entity, in the same direction and opposite senses.
• the reference system is identified specifically by the transversal, longitudinal centre-line plane of the cylinder, and not already by one of its ends, as in the known art.
• the piece-holder head and tailstock centre are integral in their translation movement with respect to the frame of the machine, for example by coupling them both with the same screw, so that a rotation of the latter causes the same movement of both, in the same direction but in opposite senses.
• the central reference system coincid- ing with the longitudinal centre-line plane of the cylinder, offers other advantages: if, for example, an odd number of lunettes (one, three, etc.) is used, it is not necessary to reposition the lunette or central contrast device each time, which is preferably fixed on the ma- chine in the position in which the centre-line of the cylinder is assembled.
• the positioning of the side lunettes is simplified as the distances can be measured by the central reference system, i.e. the centre-line of the cylinder simplifying the movement and avoiding possible er- rors .
• FIG. 1 illustrates a machine according to the present invention
• figure 2 illustrates a detail of the machine of figure 1
• step A above can possibly coincide with the positioning of the transversal, longitudinal centre-line plane of said cylinder in correspondence with a fixed lunette with respect to the frame of the machine and/or with respect to the side lunettes .
• step A the reference point, this is preferably fixed onto the machine and coincides with a lunette or contrast device, in particular with the central lunette, as will appear more evident below, in the description of the machine.
• This lunette can obviously be removed to allow the grinding of cylinders having a particular form and geometry.
• Both the piece-holder head and tailstock centre can preferably be moved so as to be always equidistant from the reference point: their movement, in other words, is of the same entity and is always effected in the same direction but in opposite senses.
• side lunettes or those situated at the sides of the central lunette which coin- cides with the reference point, these can be advantageously moved to the same degree and in the same direction, but in opposite senses. There can be one or more of these side lunettes but always in the same quantity on both sides with respect to the central lunette.
• the grinding machine 10 comprises a base 11 on which a piece-holder head 13 and tailstock centre 12 are mova- bly assembled, which serve to move and possibly support a cylinder 14 which is positioned between them during the grinding operation.
• the machine 10 is of the type in which the processing cylinder is supported by two rotating centres 81 and 83 positioned in the piece-holder head 13 and tailstock centre 12.
• the lunettes 20,21,22 are positioned in contact with the cylinder and have the function of providing a contrast to the possible bending of the cylinder due to the same processing.
• the machine 10 can equivalently be of a different type, in which the lunettes, in addition to having the function described above, also have the function of supporting the whole weight of the cylinder being processed, whereas the piece-holder head and tailstock centre only have the function of bringing it into rotation, to allow its grinding .
• the piece-holder head 13 comprises a single body which is capable of translating thanks to the presence, in the lower part, of two linear guides 80 with which it is coupled by means of suitable sliding blocks.
• the rotating centre 81 can be housed inside the body of the piece-holder head 13, which, in some applications, forms a rest for the cylinder.
• a motor 71 can be positioned, with the rela- tive transmission, for rotating the cylinder.
• the tailstock centre 12 also comprises a body which is capable of translating thanks to the presence of two linear guides 80 situated in the lower part of the structure with which it is coupled by means of suitable slid- ing blocks.
• the movable centre 83 can be housed inside the tailstock centre 12, which, in some applications, forms a second rest for the cylinder.
• the tailstock centre 12 can house a device in its lower part, which generates a preloading through a spring device.
• This preloading acts in an axial direction and guarantees the continuous contact between the cylinder and two movable centres 81 and 83 and, at the same time, the desired axial preloading, if this is required by the processing, as is the case, for example, in the grinding of so-called "thin" cylinders.
• the machine 10 also comprises a grinding wheel which can be moved parallelly to the axis of the cylinder, not shown for the sake of conciseness, and in any case known in itself in this type of grinding machine.
• Both the piece-holder head 13 and tailstock centre 12 can be moved linearly along the base 11 so that they can move towards or away from each other, to house cylinders having different lengths.
• the piece-holder head 13 and tailstock centre 12 are coupled to movement means which allow their linear approach or withdrawal movement to the same extent, in the same direction and in opposite senses.
• the movement means of this example comprise a worm screw 16 engaged with both the piece-holder head 13 and tailstock centre 12, so that, when brought into rotation, the screw 16 actuates both the approach or withdrawal in the same direction along which the screw 16 extends; these movement means are illustrated in more detail in figure 2.
• the screw 16 produced in a single piece, has two threaded parts 160 and 161 with which a corresponding female screw of the piece-holder head 13 and tailstock centre 12 is engaged.
• the two threaded parts 160, 161 of the screw 16 have contrasting helicoidal threadings, for example an anticlockwise threading and a clockwise threading, preferably having the same pitch.
• the screw 16 is actuated in rotation by a motor 17, for example an electric brushless motor or the like.
• the machine 10 also comprises contrast or supporting lunettes 20,21,22.
• the set of lunettes always comprises a central lunette 20 or, more generally, the central lunette 20 and two side lunettes 21 and 22, or four side lunettes etc.
• the cylinder is assembled with its transversal, longitudinal centre-line plane (which, as in the case of so-called “thin” or Sendzimir cylinders, often coincides with the symmetry plane passing through the barycentre and perpendicular to the generatrices of the cylinder) in a position corresponding to the central lunette 20.
• the latter at least in the case mentioned above, is consequently generally fixed in position with respect to the machine 10 or at its base destined for resting on the ground, and does not have to be moved when cylinders having different lengths are being processed, as, in any case, the longitudinal centre-line point of the cylinder is always assembled in correspondence with said central lunette 20.
• central lunette 20 it is also possible to mechanically fix the central lunette 20 to the machine 10, for example by means of screws or bolts, or make it integral with at least part of the base 12, so that it represents a cen- tral and privileged reference point for the measurement and calculation of other dimensions.
• a variant envisages controlling the position of both the lunettes 20, 21, 22 and the piece- holder head 13 and tailstock centre 12 by means of a sin- gle screw command and a series of threaded sleeves 90 (one for each device to be moved) shown in figures 3 and 4 enclosed.
• Each sleeve 90 comprises a cylindrical mantle and is engaged with the worm screw 16 by means of a threading inside the same mantle.
• Each sleeve 90 can also be connected to the unit to be moved by means of a suitable mechanism.
• the blocking means of the unit to be moved can comprise electromagnets, mechanical coupling means such as fixing pegs, wedges, removable interference profiles or other similar items.
• the coupling/decoupling means of the sleeve to the part to be positioned comprise two arms 91, 92 pivoted to the structure of the part to be moved (piece-holder head, tailstock centre and lunette) and each provided with an engagement end 93, 94 with said sleeve 90 and an opposite free end 95, 96 coupled with an actuator 97.
• the actuator 97 is preferably a linear actuator, for example a gas, pneumatic, hydraulic, electric actuator or similar: in the non-limited embodiment illustrated, it is a hydraulic actuator equipped with a cylinder and piston which protrudes variably from the cylinder.
• the actuator 97 is coupled, preferably hinged, to the free ends 95, 96 of the arms 91, 92; each engagement end 93, 94 of each arm 91, 92 is equipped with a clamp with linings for coupling with the outer cylindrical surface of the sleeve 90.
• the two arms 91, 92 have their fulcrum along their body in the points O 1 and O 1 1 so as to oscillate, so that as the two free ends 95, 96 approach, the opposite ends 93, 94 move away and vice versa.
• the machine 10 preferably comprises a single screw 16 and both the head 13 and the tailstock centre 12 and lunettes 20, 21, 22 are equipped with these coupling/decoupling means, each having a specific corresponding sleeve.
• both the lunette and the head and tailstock centre can be activated contemporaneously or separately with a single command, obtaining an extremely high versatility of the machine.
• each female screw and the part to be moved associated with it is obtained by means of a system which operates in the following way: if a certain part is to be moved, for example the tailstock centre, said blocking system constrains the threaded sleeve 90 (or female screw) to the body of the tailstock centre itself and, at the same time, prevents its rotation, so that, once actuated, the screw rotates and the female screw, constrained to the tailstock centre, cannot rotate integrally with the screw and consequently causes the tailstock centre to translate.
• the piece-holder head is to be moved and the tailstock centre kept immobile, it is sufficient to disengage the specific sleeve from the body of the tailstock centre and contemporaneously constrain that of the piece-holder head; in this way, once the screw be- gins to rotate (in this case to move the piece-holder head) the sleeve of the tailstock centre will rotate integrally with itself, maintaining the sleeve itself in the same axial position and consequently not causing any movement of the tailstock centre.
• either the lunettes or the head or the tailstock centre can be simply and rapidly activated contemporaneously or separately, to allow the cylinder to be suitably positioned and supported.
• Asymmetrical positioning of the piece-holder head and tailstock centre - symmetrical positioning of the lunettes in this case, the lunettes are synchronously positioned, making both of the female screws of the latter integral with the screw. In this way, by actuating the screw, they will move for the same distance but in opposite senses. After positioning these two groups, their female screws are disengaged from the screw. At this point, the female screw of the piece-holder head and tailstock centre are alternatingly made integral with the screw, moving first one group and then the other.
• Asymmetrical positioning of the lunettes, piece- holder head and tailstock centre with respect to the centre-line of the cylinder in this case, the groups are positioned, each time making the female screw of one group integral with the screw, whereas the female screws of the other groups not involved in the movement, are disengaged.
• This procedure can be very useful for moving the above parts in the case of the grinding of asymmetrical cylinders (such as typically hot and cold rolling cylinders) , or in applications where the piece-holder head re- mains fixed such as, in general, all applications except for the grinding of Sendzimir cylinders.
• the movement means for the head 13 and for the tailstock centre 12 and/or for the side lunettes 21 and 22, for example, can be produced differently, for example by means of a transmission belt coupled with trolleys, so as to enable the movement of the head 13 and tailstock centre 12 and/or lunettes, as envisaged above.
• the movement means can equivalently comprise two separate screws and two motors, even if, in this case, the cost of the machine is higher.
• the centre-line of the whole machine 10 can also advantageously coincide with the central lunette 20, making the positioning of the cylinder even more simple and intuitive .

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)
• Grinding Of Cylindrical And Plane Surfaces (AREA)
• Paper (AREA)
• Machine Tool Units (AREA)

Priority Applications (8)

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Publications (2)

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Citations (5)

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• 2010
  • 2010-12-22 IT ITMI2010A002348A patent/IT1403602B1/it active
• 2011
  • 2011-07-12 UA UAA201307521A patent/UA110808C2/uk unknown
  • 2011-12-07 EP EP11796635.8A patent/EP2655010B1/en active Active
  • 2011-12-07 WO PCT/EP2011/006359 patent/WO2012084155A1/en active Application Filing
  • 2011-12-07 JP JP2013545090A patent/JP5886871B2/ja active Active
  • 2011-12-07 KR KR1020137018304A patent/KR20130130778A/ko not_active Ceased
  • 2011-12-07 RU RU2013127594/02A patent/RU2580966C2/ru active
  • 2011-12-07 CA CA2821808A patent/CA2821808A1/en not_active Abandoned
  • 2011-12-07 CN CN2011800664257A patent/CN103354774A/zh active Pending
  • 2011-12-07 US US13/994,664 patent/US20140011431A1/en not_active Abandoned

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