Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D7/08—Means for treating work or cutting member to facilitate cutting
  • B26D7/12—Means for treating work or cutting member to facilitate cutting by sharpening the cutting member
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D2210/00—Machines or methods used for cutting special materials
  • B26D2210/11—Machines or methods used for cutting special materials for cutting web rolls

Definitions

• the present invention relates to a severing machine to cut elongated products, for example, although not exclusively, to divide rolls or logs of wound web material, such as tissue paper or the like, into small rolls of lesser axial length.
• the invention also relates to a method to cut elongated products, such as and in particular (although not exclusively) rolls of wound web material, such as tissue paper or the like.
• Prior Art In many industrial fields it is necessary to produce logs or rolls of wound material with or without a winding core. These rolls or logs are subsequently divided by cutting into a plurality of small rolls of smaller axial length to be packaged.
• rolls or logs of tissue paper are produced with an axial length equivalent to the width of the paper material wound in reels coming from the paper mill. These logs, which may be up to 5 m long and more, are subsequently divided into small rolls destined for consumption, of lesser axial length and with the same diameter as the one of the log.
• the severing machines used for this type of application include one or more blades normally each provided with a planetary motion, that is, rotating about an axis of rotation thereof, in turn rotating about another axis of rotation, mainly parallel to the axis of rotation of the blade. Examples of severing machines of this type are described in EP-A- 0507750, EP-A-0609668; US-A-4041813.
• the sharpening unit of a severing machine of the type indicated above comprises a pair of grinding wheels offset from each other and acting on opposite sides of the cutting chamfer of the blade.
• several sharpening units are usually used, one for each blade (see for example US- A-4,041 ,813). Examples of sharpening units for these machines are described in WO-A-0136151 and in EP-A-0528122.
• the object of the invention is to produce a severing machine of the type described above which is less complex and more economical while remaining efficient.
• the object of the invention is to produce a sharpening method which is more efficient and less complex than known methods.
• the invention discloses a severing machine to cut elongated products, comprising at least one disc blade equipped with a planetary-movement about a first axis and a sharpening device for said blade with at least one_sharpening grinding wheel, wherein the sharpening device is positioned essentially at the level of the first axis.
• Two or more disc blades may also be provided rotating about respective axes of rotation, which in turn rotate about a common central axis of rotation.
• the sharpening device can therefore remain in a fixed position rather than rotating with the blade about the axis of the planetary motion of said blade. This radically simplifies the machine. In this way a simpler configuration of the severing machine and of the respective sharpening unit is obtained.
• the contact area between blade and grinding wheel has a radial orientation, that is, theoretically lying on a line of intersection between the conical surface of the grinding wheel and of the chamfer of the blade and a plane containing the axes of the grinding wheel and of the blade. Consequently, the friction forces have a tangential orientation.
• the severing machine comprises an assembly rotating about said first axis.
• the disc blade rotating about a second axis parallel to the first axis, is carried on this assembly, so as to obtain a planetary movement of the blade.
• the grinding wheel or wheels of the sharpening device are advantageously disposed with the axis thereof essentially coincident with the first axis, about which the axis of rotation of the blade or blades rotates.
• the grinding wheel or wheels do not rotate about the axis thereof, as the sharpening movement is constituted by the movement of the blade. Nonetheless, it would also be possible, if the speeds in play so require, to make the grinding wheel or wheels of the sharpening device rotate about the axis thereof.
• the grinding wheels can be mounted idle on the axis or can be motorized and made to rotate in a direction concordant or discordant with the movement of the blade, according to the operating conditions.
• the use - of grinding ⁇ wheels which do not rotate about the axis thereof is advantageous both in terms of cost and in terms of constructional simplicity and reliability of the machine.
• the radius of the blade is suitable for the radius of the blade to be greater than the difference between the distance of said first axis from said second axis and. the radius of the grinding wheel.
• the grinding wheel or wheels of the sharpening unit have a conical active surface.
• Other solutions would also be possible, such as grinding wheels with a flat active surface, in . which case the grinding wheels must be provided with an oscillatory movement to follow the planetary movement of the blade.
• an actuator can be provided to carry the grinding wheel or wheels of the sharpening device alternatively to an operating position in contact with said blade and to an idle position, out of contact with said blade.
• a single actuator can be provided to move two grinding wheels, for example, coaxial to and opposite each other.
• the sharpening grinding wheel or wheels are carried by a support which can be integral with a piston of a double-acting piston-cylinder actuator. When the sharpening device has two grinding wheels, these can be made to operate alternately, so as to make the device particularly simple.
• the grinding wheels are disposed and controlled so that they are simultaneously in an operating position in contact with said blade, on the two opposite sides of the chamfer and, alternatively, in an idle position, in which they are both out of contact with said blade.
• the grinding wheel or wheels are connected to a fixed element by means of an elastic strip, which allows translation according to their axesr-bufenot rotation about said axis.
• the invention relates to a method to cut elongated products comprising the phases to move at least one disc blade with a planetary movement about a first axis to cut said elongated products, and to sharpen said blade with at least one grinding wheel.
• the grinding wheel is essentially maintained at the level of said first axis.
• Figure 1 shows a schematic side view, limited to the front part, of a severing machine according to the invention
• Figure 2 shows an enlargement of the rotating assembly carrying the blade and the sharpening device, as well as the fixed supporting structure of said assembly, in a section according to a plane of the trace ll-ll in Figure 2A, containing the axis of rotation
• Figure 2A shows a front view according to IIA-IIA in Figure 2
• Figure 3 shows an enlargement of the sharpening device
• Figure 4 shows a schematic view of the orbital movement of the blade during rotation of the rotating assembly which carries it
• Figure 5 shows a schematic sectional view of a modified sharpening unit
• Figure 6 shows a view according to VI-VI in Figure 5.
• Figure 1 schematically illustrates (limited to the front part) the severing machine as a whole, indicated with 1.
• the machine has a feed path of the logs to be cut, indicated with L, which are pushed by pushers 3 connected to a flexible chain member or the like 5, fed about return wheels supported by a fixed structure 7.
• L a feed path of the logs to be cut
• L a flexible chain member or the like 5
• the flexible members 5 are more than one in parallel to feed several rows of logs L according to parallel paths.
• the flexible members 5 associated with the various parallel feed channels of the logs can be motorized independently from one another to stagger the movement of the logs in the individual feed channels.
• the numeral 11 generically indicates a cutting head which, by means of a support 13, carries a rotating assembly 17.
• the assembly 17 rotates about a horizontal axis A-A parallel to the direction fl_ of feed of the logs L.
• Mounted on the rotating assembly 17 is a disc blade 19, which rotates about the axis of rotation B-B thereof parallel to the axis A-A and to the direction of feed fL of the logs L. Consequently, the blade 19 is provided with a planetary movement about the first axis A-A.
• the numeral 21 indicates a gearmotor which, in the manner described in greater detail hereunder, provides the rotating assembly 17 with the rotating movement about the axis A-A and the blade 19 with the rotating motion about the axis B-B.
• a second motor 29 rotates the return wheel 9 of the rotating member 5.
• each channel can be associated with a return wheel 9 provided with its own drive 29 suitably controlled as a function of the angular position of the rotating assembly 17.
• a programmable control unit synchronizes the forward movement of the flexible member or members 5 by means of the motor or motors 29 with the angular position of the rotating assembly 17 by controlling the motor 21.
• the rotating assembly 17 is keyed onto a hub 41 in turn keyed onto an output shaft 43 of the motor 21.
• the rotating assembly 17 carries a sleeve 45 extending parallel to the axis A-A and inside which a shaft 49 is supported, by means of bearings 47.
• the rotating disc blade 19 is fixed on the shaft 49.
• the end of the shaft 49, opposite the end carrying the blade forms a pinion 51 which meshes with a ring gear 53 fixed to a fixed plate 55 carrying the motor 21.
• the sharpening device comprises a pair of grinding wheels 63 and 65 having respective frustum-conical active surfaces 63A and 65A. These surfaces act on the chamfer B of the blade 19.
• the radius of the blade 19 both before use and at the end of its useful life is such that the chamfer B is always located in the intermediate area defined by the two opposite frustum conical surfaces 63A and 65A of the blades 63 and 65.
• the radius thereof is greater than the difference between the distance of the first axis A-A from the second axis B-B and the radius of the grinding wheels 63, 65, i.e.
• FIG. 3 shows the positions of the cutting chamfer of the blade 19 in the condition when the blade is new (chamfer B) and when the blade is at the end of its useful life (chamfer B1).
• a spacer ring 67 Disposed between the two grinding wheels 63 and 65 is a spacer ring 67.
• the two grinding wheels 63, 65, with the spacer ring 67 interposed, are blocked by means of a ring nut 69 engaging on the threaded portion 71 of a shaft 73 against a shoulder 73S of said shaft 73.
• the shaft 73 forms the rod of a piston indicated as a whole with 75, housed in a cylinder 77 formed by a cylindrical body 79 and by a front flange 81.
• the piston 75 and the cylinders 77 define two chambers with variable volume 77A and 77B, flowing into which are two ducts 83A and 83B, which extend parallel to the axis of the shaft 73 between respective top connections 85A and 85B and openings 87A and 87B composed of transverse perforations produced in the shaft 73, intersecting the holes or ducts 83A and 83B.
• the piston 87 can be moved towards an intermediate position, shown in Figure 3 (in the absence of pressure in one or other of the two chambers 77A, 77B) by means of an elastic system comprising a plurality of helical compression springs 95 and 97 housed in holes 99 and 101 produced in the flange 81 and in the cylindrical body 79 respectively. Each spring 95, 97 extends from the base of the respective hole 99, 101 to the piston 75.
• the blade 19 has parallel flat faces, that is, with a constant thickness from the outer edge (naturally excluding the chamfer B) to the inner edge in proximity of the supporting axis.
• the blade 19 could also be delimited by opposite conical surfaces, thus having a thickness gradually increasing from the outer edge towards the axis.
• the cylindrical body 79 which forms, with the front flange 81, the cylinder 77 in which the piston 75 is inserted and slides, is supported by means of bearings 107 inserted inside a bushing 109. The latter is fixed by means of screws 110 on the hub 41.
• Interposing of the bearings 107 between the bushing 109 and the cylindrical body 79 means that the latter, with the shaft 73 housed therein, can be held fixed, that is, without rotating, while the shaft 43 controlled by the gearmotor 21 rotates to make the hub 41, the rotating assembly 17 and the blade 19 rotate.
• an elastic strip 111 is fixed at the end of the shaft 73, with the opposite end of said strip connected to a column 113 fixed to the fixed structure or plate 55. In this way, bending of the elastic strip 111 allows the limited axial movement required by the shaft 73 to alternately bring the grinding wheel 63 and the grinding wheel 65 into contact with the sides of the chamfer B of the blade 19.
• the elastic strip 111 prevents the shaft 73 and the cylindrical body 79 from being drawn in rotation together with the hub 41. Consequently, the axis of the grinding wheels 63 and 65 is stationary and coincides with the axis A-A of the rotating assembly 17. Moreover, the grinding wheels do not rotate with the assembly 17 ⁇
• the ⁇ sharpening - movement is, ir fact, allocated solely to the blade 19 which ( Figure 4), through the effect of the planetary movement thereof, defines with the cutting edge thereof the envelope circumference C. This lies on a cylindrical surface coaxial to the axis A-A and intersecting the active surfaces 63A and 65A of the two grinding wheels 63 and 65.
• Sharpening is therefore obtained thanks to the planetary movement of the blade 19, while the grinding wheels remain fixed.
• the sharpening device 61 has two grinding wheels 63, 65 as in the example shown, these will act alternately, causing stress on the blade 19 in a direction essentially parallel to the axis B-B. This stress can cause a slight bending of the blade which, in any case, has minimum and negligible repercussions oh the cut of the logs L. If, nonetheless, it is desirable to eliminate any potential negative effect on the cut of the logs caused by stresses applied by the grinding wheels 63, 65 on the blade 19, one or other of said grinding wheels can be operated alternately when the blade 19 has withdrawn from the product to be cut.
• radial pins 73P used as a reference for the grooves 63B, 63C and 65B, 65C of the grinding wheels 63, 65 respectively.
• the two grinding wheels are placed on the shaft 73 so that they can engage with the pins 73P at the level of the grooves 63B and 65B.
• the ring nut 69 can be unscrewed, the grinding wheels 63, 65 partially removed to disengage them from the pins 73P, rotated:by 180° about the axis A-A and then re-inserted, inserting the pins 73B in the grooves 63C and 65C respectively.
• the two grinding wheels 63, 65 are operated by a single piston-cylinder system 77, 75 to bring them into contact with the blade 19 alternately. It would also be possible to provide a sharpening device 61 in which the grinding wheels 63, 65 are provided with two independent actuators to be respectively moved towards and away from the two sides of the chamfer B of the blade 19.
• Figures 5 and 6 schematically show a modified embodiment of the grinding wheels of the sharpening unit. In this case the grinding wheels, again indicated with 63 and 65, are produced in segments.
• each grinding wheel has a central hub 63X, 65X, extending from each of which are segments of a respective conical wall, indicated with 63Y and 65Y.
• the segments of the two grinding wheels intersect, as can be seen in the section in Figure 5 and disposed on the convex surfaces of the segments of conical wall are hard abrasive facings which act on the sides of the chamfer of the blade 19.
• the movement towards the sides of the chamfer of the blade 19 is obtained by reciprocally moving the grinding wheels away from, rather than towards each other. On the contrary, by moving the grinding wheels towards each other the active surface thereof is detached from the blade 19.
• the moving towards and away from movement can be obtained in various ways, for example, by means of a pneumatic or hydraulic piston-cylinder system, by means of an articulated parallelogram control or, as shown in the drawing, by means of a shaft 74 which has two threaded portions 74A, 74B with opposed threads, so that rotation of the shaft 74 in one direction causes the grinding wheels to move reciprocally towards each other and in the other direction causes the grinding wheels to move away from each other.
• the movement to move the grinding wheels away from and towards each other can be used to bring the grinding wheels into contact with the ⁇ blade/ that is, to he operating position, and to detach them from the blade and take them to the idle position. This movement is also used to recover wear on the blade.
• each grinding wheel 63, 65 with the blade 19 can be provided, connected rigidly to the structure of the machine, which prevent bending deformation of the blade 19 in one or other direction. It is understood that the drawing merely shows an example provided purely as a practical embodiment of the invention, which may vary in forms and arrangements without however departing from the scope of the concept on w ich the invention is based.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Nonmetal Cutting Devices (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)

Applications Claiming Priority (2)

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• 2004
  • 2004-04-01 IT IT000079A patent/ITFI20040079A1/it unknown
• 2005
  • 2005-03-31 DE DE602005020261T patent/DE602005020261D1/de active Active
  • 2005-03-31 ES ES05734818T patent/ES2341012T3/es active Active
  • 2005-03-31 WO PCT/IT2005/000177 patent/WO2005095069A1/en active Application Filing
  • 2005-03-31 AT AT05734818T patent/ATE462540T1/de not_active IP Right Cessation
  • 2005-03-31 CN CNB2005800134096A patent/CN100522518C/zh not_active Expired - Fee Related
  • 2005-03-31 EP EP05734818A patent/EP1729937B1/de not_active Not-in-force

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