A device for longitudinally slitting a continuous weblike material and a rewinder comprising said device

Abstract: The device for longitudinally slitting a continuous weblike material comprises at least one first series of rotating discoidal slitting tools (21), each tool being mounted on its own respective support (23) equipped with its own drive motor. The motor is contained within the dimensions of said support and of said tool.

Description: The present invention relates to a slitter device for longitudinally slitting a continuous weblike material into a plurality of strips. More particularly, the invention relates to a slitter device of the type comprising at least one first series of rotating discoidal slitting tools mounted on respective supports that can be adjusted and clamped along a positioning track and are equipped with individual drive motors. The invention also relates to a rewinder comprising a slitter device of the abovementioned type. In very many fields, and especially in the field of the production and conversion of paper, fabrics, nonwovens and other manufactured goods in the form of a continuous web or sheet, the weblike material has to be unwound from a large reel of large diameter and rewound to form rolls of smaller dimensions. The axial dimension of the rolls is often less than the axial dimension of the starting reel. It is therefore necessary to slit the weblike material longitudinally as it is being fed to the winding zone of the rewinder. Slitter units are provided for this purpose, comprising at least one series of discoidal tools, particularly in the form of circular cutters. Normally there are a first series of discoidal cutters and a second series of discoidal mating cutters, although alternative solutions are possible, in which the discoidal cutters act in conjunction with other backing systems. A rewinder comprising a slitter unit for dividing the incoming weblike material into a plurality of strips which then go on to form the various rolls in the winding zone is disclosed in EP-A-0818409. In certain cases, when discoidal cutters are being used in conjunction with mating discoidal cutters, the mating cutters are motorized and turn the cutters by friction, the cutters being pressed against the lateral surface of the mating cutters. In this situation the mating cutters can be mounted on a rotating shaft or bar which takes its motion from a motor at the side. If the cutters are motorized as well, they can be mounted on their own rotating shaft or bar which is also motorized. The bar carrying the cutters and/or mating cutters is typically expandable to lock the tools in the desired position. US-A-4,210,045 discloses a slitter unit in which the drive to the mating cutters is supplied via a motor shaft and a series of belt transmissions, thus enabling the axis of the mating cutters to be inclined relative to the motor shaft. EP-B-0347060 and EP-B-0499340 disclose a slitter device comprising pairs of cutters and mating cutters. The cutters are turned by the mating cutters by friction. The latter each have a drive motor. Each motor/mating cutter unit is supported on a slide fitted with an upright that supports the motor. The motor housing projects to one side from the upright, while the motor shaft and the mating cutter attached to it project from the opposite side of the upright. There are serious problems with slitter units that use a rotating bar to support the tools (whether cutters or mating cutters), including: the difficulty of dismantling the tools for sharpening; the difficulty of moving the tools when positioning them; vibration of the slitter unit support beam caused by the vibration of the bar; winding of the weblike material around the bar in the event of accidental breakage; the difficulty of inserting additional slitter tools; and high noise levels. On the other hand, slitter units equipped with individual motors for each tool, as described for example in EP-B-0347060 and in EP-B-0499340 present other problems due to the large amount of space taken up by the individual drive motors of the slitter tools. This imposes limits on how narrow the individual rolls can be made owing to the size of the individual motors. US-A-4,520,704 discloses a motor driven slitter with a narrow configuration. Each slitter blade is supported by its own support, which also supports a driving motor for the blade. According to an embodiment suggested therein, the motor can be a pancake motor. No specific design for such pancake motor is disclosed. It is an object of the present invention to provide a slitter device of the type referred to at the outset that overcomes the problems of conventional rotating-bar devices and at the same time is capable of producing rolls of even quite small axial dimensions, that is it can slit relatively narrow strips of weblike material by setting the slitter tools closer together. These and other objects and advantages, which will become clear to those skilled in the art upon reading the text which follows, are achieved with a device according to claim 1. In essence the device according to the invention includes at least one first series of rotating discoidal slitting tools, each tool being mounted on its own support which can preferably be adjusted and clamped along a positioning guide and being equipped with its own drive motor, characterized in that the drive motor of the slitter tool is contained within the dimensions of its support and of said tool. In one particularly advantageous embodiment of the invention, the support of the rotating discoidal tool comprises a body defining internally a roughly approximately cylindrical seat, in which is housed the stator of the drive motor of the tool. A mounting spindle extending into said seat, on which the rotor of said motor is supported, is integral with the body. The rotor may have a hollow shaft mounted on the mounting spindle. Extremely small axial dimensions can be achieved with this configuration, therefore allowing the various slitter tools to be set close together to produce strips of weblike material of even very small width, e.g. of around 50 mm. In one practical embodiment of the invention, a flange, to which the slitting tool is attached or which forms part of it, is integral with the hollow shaft of the rotor. The flange may be attached to the hollow shaft or, preferably, is made in one piece with it. The flange may have an annular cavity into which a portion of the stator may project. This further reduces the overall size of the device. In one practical embodiment, the flange may have an axial fitting hole and is equipped with a cover that closes said hole. The mounting spindle may be fitted into the stator seat in various ways. In one particularly advantageous embodiment of the invention, the seat of the stator has a back wall with a central through aperture into which one end of said mounting spindle is inserted. This gives a compact structure capable of withstanding large stresses. In practice, it is advantageous if the central through aperture is surrounded by an annular ridge with through seats for screws for fastening the mounting spindle, said seats being accessible such that said screws can be screwed from the side away from the stator. It is also advantageous if the mounting spindle has a clamping flange by means of which said spindle is clamped to the back wall of the seat of the stator. To reduce the axial size, it is particularly advantageous, moreover, for the hollow shaft of the rotor to house a single bearing, such as a double-row ball bearing. The invention also relates to a rewinder for producing rolls of wound weblike material, comprising a winding unit, a path along which the weblike material is fed to said winding unit and a slitter device for dividing said weblike material into a plurality of strips, each intended to form one roll of weblike material, characterized in that said slitter device is constructed as defined above. A clearer understanding of the invention will be gained from the description and the attached drawing, the latter showing a practical non-limiting illustrative embodiment of the invention. More specifically, in the drawing: Fig. 1 shows a schematic side view of a rewinder with a slitter device produced in accordance with the invention; Fig. 2 shows an enlargement of the slitter device; Fig. 3 shows an end view of a rotating discoidal tool and more particularly a mating cutter belonging to the device shown in Fig. 2; and Fig. 4 shows a section taken on IV-IV as marked in Fig. 3. Fig. 1 illustrates generically and schematically a rewinder 1 comprising two winding rollers 3, 5 on which a series of mutually coaxial rolls R are formed. The rolls R are formed from strips of weblike material S produced by slitting lengthwise a single weblike material N coming from a parent reel (not shown) unwound inside an unwinder (also not shown) of a type known per se. In order to slit the weblike material N into strips narrower than the material N, a slitter device, marked 9 in a general way, is provided: it comprises a series of mutually coaxial discoidal cutters 11 aligned along an axis A (see in particular Fig. 2). Only one cutter can be seen in the drawing, but it should be understood that there are a plurality of cutters along the axis A, sufficient in number to slit the weblike material N into the desired number of strips required for the particular job. Each cutter is mounted on a support 13. Each support 13 travels along tracks 15 parallel to the axis A and perpendicular to the direction of forward travel of the weblike material N and of the strips S into which it is divided by the slitter device 9. In this way, each support can be moved to the point where the longitudinal slit is to be made in the weblike material N. The positioning of each slitter tool 11,13 can be performed in a manner known per se using a positioning device, marked 17 in a general way, and the clamping of the slitter tools in the desired positions can be done in a manner known per se which is not relevant to the present invention. For each discoidal cutter 11, the slitter device 9 includes a mating cutter 21, each mounted on its own support 23. The figures show only one mating cutter 21, but it must be realized that there are a plurality of identical mating cutters along the axis B (parallel to the axis A). Each support 23 is positionable along tracks 25 parallel to the axis B. The reference 27 is a general indication for a positioning device, which may be of any type and is not relevant for the purposes of the present description, for positioning the mating cutters 21 along the tracks 25. The cutters 11 and the mating cutters 21 constitute two series of rotating discoidal slitter tools. The account given below referring to the actuation of the mating cutters can also be applied to the actuation of a different type of discoidal slitting tool, e.g. a slitting cutter. If both the tools (cutter and mating cutter) are to be motorized, the solution described for driving the mating cutters 21 can be used for the actuation of the cutters. The various mating cutters are all the same as each other and only one of them, together with its support, will be described in detail with reference to Figs. 3 and 4. It is not ruled out that the slitter device may also include mating cutters that differ in configuration and actuation from those whose structure is as illustrated in Figs. 3 3 and 4. Each mating cutter 21 has an electric drive motor. This motor comprises a stator 31 and a rotor 33. The stator 31 is housed in a roughly approximately cylindrical seat 35 made in the body 23A of the mating cutter support 23. The seat 35 has a back wall 37 containing a large circular aperture 37A surrounded by an annular ridge 37B. Around the circumference of the annular ridge 37B are seats 37C for fastening screws for clamping a spindle 39 on which the rotor 33 is mounted. The mounting spindle 39 has one end whose diameter is approximately equal to the diameter of the aperture 37A and is inserted into this aperture. The end 39A terminates in a shoulder defined by a fixing flange 39B with threaded holes for the engagement of the fastening screws inserted into the seats 37C of the annular ridge 37B. On the opposite side of the fixing flange 39B from the end 39A of the mounting spindle 39, said spindle 39 continues and forms the seat for a bearing 41 on which fits a hollow shaft 43 around which the rotor 33 is formed. The number 45 denotes a disk screwed onto the corresponding end of the mounting spindle 39 so as to lock the inner ring of the bearing 41. On the other side, the inner ring is locked by a shoulder 39B formed on the mounting spindle 39. The bearing 41 may advantageously be a double-row ball bearing or equivalent means, so that it can also take bending moments and loads parallel to the mounting spindle 39, thus making two bearings unnecessary. The hollow shaft 43 extends radially outside the support 23, eventually forming a flange 47, screwed to which, with screws 50, is a ring 49 forming the active portion of the mating cutter 21. The ring 49 has a conical annular surface 49A of large aperture which acts in combination with the slitting cutter 11, as indicated in chain line in Figs. 3 and 4. The through hole in the hollow shaft 43 is closed by a cover 51 screwed by screws 53 to the flange 47 and forming an abutment to hold the outer ring of the bearing 41 in place. The abutment on the opposite side of the outer ring is formed by a collar 43A made in one piece with the hollow shaft 43. The construction described above is axially very compact and the total axial dimension D of the mating cutter 21 with the support 23 may even be equal to or less than 50 mm. The axial dimension is very small partly because of the fact that the stator (which is one of the largest components) projects on one side into an annular cavity 47X formed in the flange 47 and on the other into a similar annular cavity recessed into the back wall 37 which defines the seat 35. This back wall could also be produced in the form of a separate flange which is then fixed in position. Also shown in Fig. 4 is a hole 61 to take the electric wire. Another hole (not shown) can be provided so that air can be blown in under gentle pressure into the seat 35 to prevent dust getting into the motor. In addition or as an alternative, a labyrinth seal indicated schematically at 63 may be used. It will be understood that the drawing shows only one possible non-limiting embodiment of the invention, which can be varied in its shapes and arrangements without thereby departing from the scope of the concept underlying the invention, as defined in the accompanying claims. The presence of any reference numbers in the claims is for the purpose of facilitating the reading thereof in the light of the preceding text and of the accompanying drawings and does not limit the scope of protection thereof.

Claims: A device for longitudinally slitting a continuous weblike material, comprising at least one first series of rotating discoidal slitting tools (21), each tool being mounted on its own support (23) equipped with its own drive motor including a stator (31) and a rotor (33), characterized in that said motor is contained within the dimensions of said support and of said tool, said support including a roughly approximately cylindrical seat (35) in which said stator and said rotor are arranged, said stator and said rotor surrounding each other, the tool (21) being co-axial to said rotor and said stator. Device according to claim 1 characterized in that said support (23) comprises a body (23A) defining internally said approximately cylindrical seat (35), and in that a mounting spindle (39) extending into said roughly approximately cylindrical seat (35), on which a rotor (33) of said motor is mounted, is integral with said body. Device according to claim 2, characterized in that said rotor has a hollow shaft (43) mounted on said mounting spindle (39). Device according to claim 1 or 2 or 3, characterized in that said supports (23) can be adjusted and clamped along a positioning track (25). Device according to claim 3, characterized in that a flange (47), to which the slitting tool (21) is attached or which forms part of it, is integral with said hollow shaft of the rotor. Device according to claim 5, characterized in that said flange is made in one piece with said hollow shaft. Device according to claim 5 or 6, characterized in that said flange has an annular cavity (47X) into which the stator (31) of said motor projects. Device according to claim 5, 6 or 7, characterized in that said flange has an axial fitting hole and is equipped with a cover (51) that closes said hole. Device according to one or more of claims 1 to 8, characterized in that said approximately cylindrical seat has a back wall (37) with an annular groove to house a projecting portion of the stator. Device according to one or more of claims 1 to 9, characterized in that said roughly approximately cylindrical seat has a back wall (37) with a central through aperture (37A) into which one end (39A) of said mounting spindle (39) is inserted. Device according to claim 10, characterized in that said central through aperture (37A) is surrounded by an annular ridge (37B) with through seats (37C) for screws for fastening the mounting spindle (39), said seats being accessible such that said fastening screws can be screwed from the side away from the stator (33). Device according to claim 10 or 11, characterized in that the mounting spindle has a clamping flange (39B) by means of which said spindle is clamped to the back wall of said roughly approximately cylindrical seat. Device according to one or more of claims 3 to 12, characterized in that said hollow shaft of the rotor houses a single bearing (41). Device according to one or more of the previous claims, characterized in that the total axial dimension of said support and said slitting tool is equal to or less than 50 mm. Device according to one or more of the previous claims, characterized in that it comprises a second series of rotating discoidal slitting tools (11), the tools (11) of said second series acting in conjunction with the tools (21) of said first series. A rewinder for producing rolls of wound weblike material, comprising a winding unit, a path along which the weblike material is fed to said winding unit and a slitter device for dividing said weblike material into a plurality of strips, each intended to form one roll of weblike material, characterized in that said slitter device is constructed in accordance with one or more of the previous claims.

Inventors: ACCIARI GIUSEPPE, ACCIARI, GIUSEPPE
Applicants: CELLI NONWOVENS SPA, A. CELLI NONWOVENS S.P.A.
Application year: 2001
Main classification: B65H35
IPC codes: B26D5, B65H35