BLADE HOLDER UNIT IN ROTARY SCISSOR CUTTING EQUIPMENT FOR SHEET MATERIALS

Description

Description of the utility model entitled: "BLADE HOLDER UNIT IN RO SCISSOR CUTTING EQUIPMENT "SHEET MATERIALS PRODUCTION" on behalf of: Felice ESPOSITO and Francesco ESPOSITO in Milan and Magenta (Milan) filed on 24 GYN. 1990 20484 B / 90 * A ★ * * * A This utility model relates to a blade holder unit intended to support and position the cutting assembly in equipment for rotary scissor cutting of sheet materials. This type of equipment typically comprises multiple cutting devices positioned side by side to simultaneously cut large sheet materials, such as paper, cardboard, plastic, metal, and the like, into strips at high speed. Each cutting device comprises a blade holder unit, to which the cutting unit is pivoted and freely rotates. The cutting unit contains a disc with a sharp edge, which constitutes the cutting blade. The rotary motion is applied to the cutting disc by a counter-disc located under the work surface. The counter-disc is rotated by special motors and transmits its motion to the cutting disc when the latter is pressed against its lateral surface. To allow for correct processing and good access The disc holder unit allows for at least two types of movement for the cutting unit, one perpendicular to the cutting plane and one parallel to it. The first movement allows the cutting disc to be moved radially towards and away from the counter disc, a movement necessary for accessing the parts when machining is not taking place. The second movement moves the edge of the cutting disc laterally towards the corresponding edge of the counter disc, and also maintains contact between these two parts with the necessary pressure to prevent slippage between the two discs. When the cutting disc and counter-disc are brought into contact and rotate together, the material to be cut is advanced towards them. Since, as stated above, the two discs are not tangent, but rather their external profiles partially overlap, the sheet resting on the outer circumferential surface of the counter-disc is gripped between the two discs and simultaneously cut with great precision with a movement very similar to that obtained when cutting with scissors, hence the name "rotary scissor cutting". It should also be noted that the cuts can be interrupted at any time by removing the cutting disc from the counter-disc, and resumed, after having changed the position of the cutting device if necessary, even without first removing the sheet material being processed. This will in fact be cut during the lowering of the cutting disc, therefore the cutting will continue as illustrated above as soon as the cutting disc and counter disc come into contact again. While the counter-blades are an integral part of the equipment and are permanently mounted to it, the cutting blades must be easily and quickly adjustable to allow the selection of the blade best suited to the material being cut. Furthermore, their angle relative to the cutting direction must be precisely adjusted and maintained to avoid blurry, irregular cuts, cuts with swarf, or other similar problems, and to prevent premature or uneven wear of the cutting blades. In known blade holder units, these operations can only be performed in an inefficient, imprecise and poorly repeatable manner, and therefore the need for improved blade holder units is strongly felt in the sector. With this requirement in mind, the inventors of this model have studied and developed an innovative blade holder unit designed to brilliantly address all the needs that have arisen in the sector for the improvement of this device. More specifically, the blade holder unit of this model is highly compact and simple to construct thanks to a renewed design of the pneumatic part; it allows for quick and easy adjustment of the cutting angle, and It allows for perfect repeatability over time regardless of the presence of play or wear of the device; it facilitates the easy disassembly of the cutting disc and allows it to be housed in a location much closer to the longitudinal axis. <fell'unità portalama rispetto a quanto avviene nelle unità portatane note, evitando così 1'insorgere di elevati sforzi torsional i e consentendo di conseguenza un alleggerimento dell’intera construction with equal rigidity. These remarkable results are obtained, according to the present model, by means of a blade-holder unit which comprises a first fluid-pressure cylinder-piston group, a second fluid-pressure cylinder-piston group fixed transversely to the piston of the first group, a cutting group pivoted, free to rotate, on the piston of the second group, means for supplying fluid to the fluid inlet chamber of the cylinder of the first group, means for communicating fluid between said chamber and the corresponding chamber of the cylinder of the second group, means for making the cylinder and the piston of the first group mutually integral for rotation and means for radially adjustable support of the cylinder of the first group. group. Other features and advantages of this model will however become more evident from the detailed description that follows of a preferred form of execution of the same, provided for illustrative purposes only and illustrated in the annexes. drawings, in which: fig. 1 is an elevational and partially sectional view of the blade holder unit according to the present model; fig. 2 is a sectional view along line II-II of fig. 1 illustrating the cylinder support collar of the first cylinder-piston group; fig. 3 is a view similar to fig. 1 according to the point of view indicated by the arrow III in fig. 1; fig. 4 is a sectional view along the TV-IV line of fig. 3; fig. 5 is an elevation view illustrating the detail of the radial adjustment and support device of the blade holder unit of the present model; and Fig. 6 is a plan view of the same device illustrated in Fig. 5. The blade holder unit of this model comprises a cylindrical element 1, inside which a piston 2 slides. The blade holder unit is positioned such that the axis of this cylinder-piston assembly is essentially perpendicular to the sliding plane of the sheet material to be cut. A second cylinder-piston assembly 3-4, designed to support the cutting assembly, is integral with one end of piston 2; a knurled nut 5 is screwed to the opposite end of piston 2. The axial position of nut 5 with respect to piston 2 can be fixed as desired by screwing or unscrewing the nut itself on the threaded end 2a of piston 2, and locking it in the desired position by means of grub screw 6. In this way, the length of the useful stroke of piston 2 is determined, or more precisely its lower limit of travel given by the engagement of nut 5 with the external surface of cylinder 1; the upper limit of travel is instead determined by the engagement of piston 7 of piston 2 with the head of cylinder 1. The upper limit of travel position is the one in which maintenance operations are carried out on the equipment and therefore does not require the possibility of adjustment; on the contrary, the lower limit of travel position is the working position of the blade holder unit and must be able to be appropriately calibrated to allow the correct overlap between cutting disc and drive counter disc. The cylinder-piston assembly 1-2 is of the fluid-operated type, preferably pneumatically operated. The pressurized fluid enters the upper chamber 8 of the cylinder 1 via the control valve 9 and causes the piston 7 to move downwards. This movement of the piston 7 is counteracted by spring means 11 which are arranged in the lower chamber 10 of the cylinder 1 and which automatically return the piston 2 to its top dead centre whenever the supply of pressurized fluid is suspended via the valve 9. To deactivate the operation of a single blade-holder unit, without discharging the pressurized fluid from the entire line - which usually supplies a plurality of blade-holder units placed side by side - it is then An exhaust valve 12 is provided. This valve can be opened when valve 9 is closed, allowing the pressurized fluid contained within cylinder 1 to escape through the valve itself thanks to the action of spring 11, and the piston returns to its rest position at top dead center. Alternatively, a three-way valve can be provided along the pressurized fluid supply line, before or after control valve 9, to allow the interruption of the pressurized fluid supply to the specific blade holder unit and the simultaneous discharge of the fluid already contained within the unit. As mentioned above, a cylinder-piston group is fixed to the lower end of the piston 2, consisting of a cylinder 3 integral with the piston 2 and a piston 4 on which the cutting group, schematically represented in fig. 1 by the cutting disc 13 alone, is fixed, free to rotate. Spring means 15 acting between the cylinder 3 and the piston 4 maintain the latter, when the pressure of the working fluid is absent, in the position illustrated in fig. 1, in which the cutting disc 13 is laterally separated from the corresponding drive counter-disc 16, of which only the top is schematically illustrated in fig. 1. The left end-of-stroke, or working, position of the piston 4 is adjustable and is determined by the position of a knurled-head screw 14, screwed into the bottom of the cylinder 3. The stem of the screw 14 is arranged inside the charm means 15 and, against the its end, the cylinder 4 abuts; thus the contact pressure of the cutting disc 13 on the counter disc 16 can be finely adjusted. The movement of piston 4 is imparted by the same working fluid that actuates piston 2. The latter in fact has an axial cavity 18 which, via holes 17 and 19, connects the upper chamber 8 of cylinder 1 with the right chamber 20 of cylinder 3. However, this communication only occurs after piston 2 has already moved from its top dead center a distance sufficient to bring hole 17 into correspondence with chamber 8; this therefore causes a delay in the movement of piston 4 sufficient to ensure that cutting disc 13 comes into contact with counter disc 16 only when piston 2 has already completely completed its downward stroke. This ensures perfect safety, without the need for additional control devices, of correct coupling between cutting disc and counter disc and, in particular, avoids jamming and possible deterioration of disc 13 against the upper surface of counter disc 16. The cylinder 1 is fixed to the frame of the cutting equipment by means of a collar 21 which completely embraces it and whose shape is clearly illustrated in section in fig. 2. The collar 21 is fixed to the frame with any known means, and for example by means of a pair of bolts housed in respective seats 22, and is locked with a tie around the cylinder 1. by tightening a special screw housed in seat 23. When the operator needs to prepare the blade holder unit of this model for a new series of cuts, he first loosens the screw in seat 23 and then adjusts the radial position of the cylinder 1, and consequently that of the cutting disc 13, by acting on a lever with knob 24 screwed directly onto the body of the cylinder 1. The cylinder 1 can be completely rotated 360° in both directions, both to orient the cutting disc 13 according to the different cutting requirements (longitudinal, transverse, etc.), and for maintenance, cleaning and blade replacement operations. This possibility of free rotation also allows, in a given cutting position, the fine adjustment of the cutting angle which, to obtain an optimal cut, must often differ by a few degrees from the cutting direction. To facilitate this adjustment operation, graduated scales 25 are provided on the external surface of the cylinder in correspondence with the main cutting directions. These allow, in comparison with a reference notch 26 drawn on the collar 21, the desired angular position of the cutting disc 13 to be determined quickly, accurately and in a perfectly repeatable manner (see figs. 5 and 6). As is clear from the above, the angular position of the cutting disc 13 is adjusted by acting on the angular position of the cylinder 1; it is therefore quite evident that they must Means must be provided to prevent the presence of play between cylinder 1 and piston 2. These means consist of a key 27, visible in cross-section in fig. 4, placed between cylinder 1 and piston 2 and fixed to one of these two elements; preferably the key is fixed by means of screws to piston 2 and slides in a special slot made in cylinder 1. In order to guarantee maximum precision in maintaining the chosen value of the cutting angle, a screw 28 is provided, housed in a threaded seat made in cylinder 1 and having its end part made of anti-friction material in contact with the side wall of the key 27, so as to compensate for both the necessary coupling play and any play that may subsequently occur due to wear of the parts. The blade holder unit of this model is completed with a device to facilitate the replacement of the cutting discs. As previously mentioned, the cutting group is mounted idle on cylinder 4 and it is therefore not easy to disassemble the group itself or its parts, which are usually fixed with nuts or bolts. The blade group must in fact be locked manually or with special keys by the operator while the necessary nuts or bolts are unscrewed with the free hand. The blade holder unit of this model has a longitudinal cylindrical hole 29 in its lower part, specifically in the body of cylinder 4, which completely passes through the cylinder itself. When it is necessary to disassemble the group or the cutting disc, a cylindrical pin The pin is inserted into hole 29 until it interferes with the cutting unit, fitting into a special hole, not illustrated, provided on the same. Advantageously, this pin is constituted by the lever 24 itself, after it has been unscrewed from cylinder 1, with the advantage of always having this tool immediately at hand.

Claims

CLAIMS 1) Wool carrier unit in equipment for rotary shear cutting of sheet materials characterised by what comprises: a first fluid-pressure cylinder-piston group (1-2); a second fluid-pressure cylinder-piston group (3-4) fixed to the piston (2) of the first group in a direction orthogonal to the axis of the latter; a cutting group pivoted, free to rotate, on the piston (4) of the second group; means for introducing fluid (9) into the fluid inlet chamber (8) of the cylinder (1) of the first group; means for communicating fluid (17, 18, 19) between the fluid inlet chamber (8) of the cylinder (1) of the first group and the corresponding chamber (20) of the cylinder (3) of the second group; means for making the cylinder (1) and the piston (2) of the first group mutually integral for rotation; and means (21) for radially adjustable support of the cylinder (1) of the first group. 2) Blade holder unit as in 1), where the cylinder (4) of the second grip is drilled longitudinally to accommodate a locking pin of the cutting group. 3) Blade holder unit as in 1), wherein said cylinder support means (1) of the first group consist of a collar (21) equipped with devices (22) for fixing to the frame, tightened in a tie around the external surface of the cylinder. 4) Blade holder unit as in 3), wherein the reciprocal radial position between support collar (21) and cylinder (1) is indicated by the position of a graduated scale (25) shown on one of these elements with respect to a reference mark (26) shown on the other of them. 5) Blade holder unit as in 1), wherein said means for making the cylinder (1) and the piston (2) of the first group mutually integral consist of a key (27) integral with the piston and sliding axially in a slot of the cylinder. 6) Blade holder unit as in 5), where in said cylinder (1) there is a screw (28) with a tip in anti-friction material which acts against the lateral surface of the key (27) to recover the coupling and wear play. 7) Blade holder unit as in 1), wherein said fluid communication means consist of a cavity (18) formed inside the piston of the first group. 8) Blade holder unit as in 7), wherein said cavity (18) enters into communication with the fluid inlet chamber (8) of the cylinder (1) of the first group, when the piston (2) in which the cavity (18) is obtained has already started the movement towards its working position. 9) Blade holder unit as in 1), wherein said first and second cylinder-piston groups comprise spring means (11, 15) to maintain the relative pistons, in the absence of fluid pressure, in the dead point opposite to the working point. 10) Blade holder unit as in 1), wherein said cylinders of the first and second group comprise, at one end thereof, screw means (5, 14) for adjusting the position of the working dead centre. 11) Blade holder unit as in 1), wherein said means for supplying pressurized fluid consist of a pressure regulating valve (9). 12) Blade holder unit as in 1), further comprising a quick exhaust valve (12) connected to the fluid inlet chamber (8) of the cylinder (1) of the first group. 13) Blade holder unit as in 1), further comprising, on the pressurized fluid supply line, a three-way valve to allow the closing of the pressurized fluid supply and the simultaneous discharge of the fluid contained within the * unit. 14) Blade holder unit as in 1), also comprising a knob lever (24) fixed to the cylinder of the first group, to allow its rotation. 15) Blade holder unit as in 2) and 14), wherein said knob lever (24), is screwably fixed to the cylinder (1), and, when free from it, it constitutes the locking pin of the wool group. (pt)

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