Method and apparatus for cutting strip material

Abstract

The apparatus for cutting strip material (2) comprises a roller (10) adapted to be rotatably driven by a motor member (11) to operate the cutting of the strip material. The strip material unwinding roller (10) peripherally has a substantially radial cavity (12) extending for the width of the roller (10) itself. A blade (20) is adapted to be driven with reciprocating motion by a tilting arm (21) on a plane substantially radial to said strip material unwinding roller (10). The blade (20) is adapted to cooperate during the cutting step with a counter-blade (13) arranged inside said cavity (12) of the strip material unwinding roller (10)

Description

DescriptionMETHOD AND APPARATUS FOR CUTTING STRIP MATERIALTechnical field

[0001] The present invention relates to a method and an apparatus for cutting strip material.Prior art

[0002] It is currently known, in various technical sectors, the use of automatic machines that use reels of strip material for manufacturing or packaging products. The operation of these automatic machines presupposes unwinding the strip material from one or more reels and feeding this strip material to the machine, in such a way as to meet the production needs of the machine itself.

[0003] In particular, it is usually required that the strip material be cut into portions of predetermined length depending on the function to be performed.

[0004] Therefore, apparatuses have been developed that are able to automatically operate the cutting of the strip material to be fed to automatic machines that use this strip material. The material is generally cut by means of a blade and a counter-blade operating in synergy on a plane transverse to the strip material unwinding plane. During the cutting step, the blade and the counter-blade are suitably angled with respect to each other; the cutting angle is progressively reduced during cutting.

[0005] In practice, the mutually cooperating blade and counter-blade cause a point contact that shifts substantially over the length of the blade to serve the cutting length it is wished to be achieved.

[0006] A requirement that arises during the strip material cutting step is that the coupling between blade and counter-blade takes place with a controlled force. To this end, the blade and counter-blade are generally subject to the action of appropriate elastic means, of a mechanical or pneumatic type. However, the currently known strip material cutting systems do not fully meet this requirement.

[0007] In general, the current development of increasingly high-performance automatic machines, which are namely capable of reaching very high production speeds, makes the need of feeding the strip material in order to meet the demands of the machines themselves pressing.Disclosure

[0008] The task of the present invention is to solve the aforementioned problems, by devising an apparatus that allows to optimally operate the cutting of strip material in automatic machines using such strip material for manufacturing or packaging products.

[0009] Within this task, a further object of the invention is to provide an apparatus that allows to control with precision the contact force acting between the blade and the counter-blade inthe cutting step.

[0010] Another object of the invention is to provide an apparatus for cutting strip material that allows a high production speed to be achieved.

[0011] A further object of the invention is to provide an apparatus for cutting strip material that is of simple constructive and functional design, provided with reliable operation, versatile use, as well as relatively economical cost.

[0012] The cited objects are achieved, according to the present invention, by the apparatus and method for cutting strip material according to claims 1 and 11.

[0013] The apparatus for cutting strip material comprises an unwinding roller adapted to be rotatably driven by a motor member to operate the cutting of the strip material.

[0014] The unwinding roller peripherally has a substantially radial cavity extending for the width of the roller itself.

[0015] Preferably the unwinding roller is limited by a first head and a second head, parallel to each other.

[0016] The distance between said heads defines the width or longitudinal extension of the unwinding roller.

[0017] The apparatus comprises a blade adapted to be driven with reciprocating motion on a plane substantially radial to said strip material unwinding roller and a counter-blade arranged inside said cavity of the strip material unwinding roller and adapted to cooperate in the cutting step with said blade.

[0018] Preferably, said blade is associated with a tilting arm configured to be rotatably driven around a longitudinal axis by a motor member.

[0019] Preferably said motor member is of the brushless type.

[0020] Said tilting arm is configured to shift the blade between a rest position and a cutting position.

[0021] Preferably, the axis of rotation of the tilting arm is arranged next to said first head of the unwinding roller.

[0022] Preferably said blade is adapted to be driven with reciprocating motion by said tilting arm between a rest position, spaced from said strip material unwinding roller, and a cutting position in which the blade engages said cavity of the roller itself.

[0023] According to one aspect of the invention, the apparatus comprises means for controlling the contact force acting reciprocally between said blade and said counter-blade during the strip material cutting step.

[0024] Advantageously, said means for controlling the contact force acting between said blade and said counter-blade comprise a stop member associated with said blade and adapted to abut, in said cutting position of the blade, an abutment member associated with said strip material unwinding roller.

[0025] Preferably, the abutment member associated with said roller is arranged proximal with respect to said second head.

[0026] Preferably, the stop member associated with said blade is arranged so as to protrude longitudinally with respect to said roller, when it is in the cutting position, from the side of said second head, so as to engage said abutment member associated with the roller.

[0027] Advantageously, said abutment member is stressed, in said cutting step, by the thrust action against said stop member exerted by a torque delivered by the motor member of said roller.

[0028] Preferably said stop member comprises a portion protruding laterally from said tilting arm of the blade.

[0029] Preferably said blade is made of hard material and is associated with said tilting arm by means of a steel support member.

[0030] According to another advantageous aspect of the invention, said counter-blade has a cutting edge provided with a cutting corner located below the borders of said cavity that are defined on the surface of said strip material unwinding roller.

[0031] Advantageously, the apparatus comprises means for adjusting the angle of incidence between the blade and the counter-blade, depending on the type of strip material to be cut.

[0032] Preferably, said means for adjusting the angle of incidence between the blade and the counter-blade are adapted to act on said blade support member by means of adjustment means.

[0033] Preferably, said strip material unwinding roller comprises suction means arranged upstream of said cavity, according to the direction of rotation of the roller itself, adapted to retain said strip material during said cutting step.

[0034] The present invention also concerns a method for cutting strip material, comprising the steps of a. arranging a roller adapted to be rotatably driven by a motor to operate the cutting of the strip material to be cut and peripherally having a substantially radial cavity extending for the width of the roller itself; b. arranging a blade adapted to be driven with reciprocating motion on a plane substantially radial to said strip material unwinding roller and adapted to cooperate during the cutting step with a counter-blade arranged inside said cavity of the strip material unwinding roller; c. feeding said strip material to said unwinding roller; d. at the time of performing the cutting of said strip material, stopping said unwinding roller; e. driving the shift of said blade in contact with said counter-blade to perform the cutting ofthe strip material; f. at the same time driving means for controlling the contact force acting reciprocally between said blade and said counter-blade during the strip material cutting step.

[0035] Preferably, said step of c. feeding said strip material to said unwinding roller provides for c1. fixing the strip to the outer surface of the roller so as to generate a surface tension on the strip, in such a way as to guarantee the cut by effect of the reciprocal actuation of said blade and said counter-blade, with the strip material interposed between the blade and the counter-blade.

[0036] Advantageously said step of f. driving means for controlling the contact force acting between said blade and said counter-blade provides for f1. bringing a stop member associated with said blade to abut, in the cutting position of the same blade, an abutment member associated with said strip material unwinding roller, and at the same time in said cutting step f2. operating a controlled thrust of said abutment member against said stop member by means of a torque delivered by the motor member of said roller.Description of the drawings

[0037] The details of the invention will become more apparent from the detailed description of a preferred embodiment of the apparatus for cutting strip material according to the invention, illustrated by way of example in the accompanying drawings, in which:

[0038] figure 1 shows a perspective view of the apparatus for cutting strip material according to the present invention;

[0039] figures 2 and 3 respectively show a perspective view of the apparatus in question according to a different inclination;

[0040] figures 4 and 5 respectively show a front view and a top view of the same apparatus;

[0041] figures 6 and 7 respectively show a side view and a front view of the apparatus for cutting strip material according to the present invention in a first operating position;

[0042] figures 8, 9 and 10, 11 show corresponding side and front views of the apparatus for cutting strip material in subsequent operating steps.Description of embodiments of the invention

[0043] With particular reference to these figures, the apparatus for cutting strip material intended in particular for use in automatic machines that use this strip material for production purposes is indicated as a whole with 1.

[0044] The apparatus 1 comprises a strip unwinding roller 10 adapted to be rotatably driven by a motor member 11 , preferably of the brushless type, to operate the cutting of the strip material to be cut. Preferably, the roller 10 is made in a tubular shape and is axiallyassociated with said motor member 11 , according to a substantially horizontal axis X.

[0045] The roller 10 peripherally has a substantially radial cavity 12 extending practically over the entire width of the roller 10 itself.

[0046] The roller 10 is limited by a first head and a second head, parallel to each other. The distance between the two heads defines the width or longitudinal extension of the roller 10.

[0047] The apparatus 1 also comprises a blade 20 adapted to be driven with reciprocating motion on a plane substantially radial to the cutting roller 10 of the strip material. In particular, the blade 20 is driven by a tilting arm 21 between a rest position, spaced from the roller 10, and a cutting position in which it engages the cavity 12 of the same roller 10, as specified below. The tilting arm 21 is commanded by a motor member 22 according to an axis of rotation parallel to the axis of the strip material cutting roller 10.

[0048] The axis of rotation Y of the arm 21 is arranged next to said first head of the roller 10.

[0049] The blade 20 is made of hard material of the type known as widia and is associated with the tilting arm 21 by means of a steel support member 23, adapted to absorb any deformations.

[0050] The blade 20 is adapted to cooperate during the cutting step with a counter-blade 13 arranged inside the cavity 12 of the strip material unwinding roller 10.

[0051] Advantageously, the cutting corner of the cutting edge of the counter-blade 13 is located below the borders of the cavity 12 that are defined on the surface of the strip material unwinding roller 10 (see fig. 4). In this way, the strip material sliding on the roller 10 extends in contact with the aforementioned borders of the cavity 12 without interfering with the counter-blade 13 located inside the cavity 12 itself. This allows to safeguard the integrity of delicate strip materials that might be easily torn or otherwise be damaged in contact with the cutting edge of the counter-blade 13.

[0052] It should be noted that the cutting edge of the blade 20 is suitably inclined with respect to the surface of the strip material unwinding roller 10 (see fig. 6). Therefore, during the movement of advancement in the cutting position, the blade 20 progressively engages the counter-blade 13 placed in the cavity 12 of the roller 10, so that the cutting point gradually shifts along the blade 20 itself.

[0053] Advantageously, the angle of incidence between the blade 20 and the counter-blade 13 can be varied by means of the support member 23 of the blade 20 itself, depending on the type of strip material to be cut. In particular, a wedge 25 acting on the support member 23 of the blade 20 is mounted slidable on the tilting arm 21 in order to vary the angular position of the blade 20 itself. The position of this wedge can be controlled by means of a special adjustment screw.

[0054] According to one aspect of the present invention, the apparatus is provided with a contactforce control system acting reciprocally between the blade 20 and the counter-blade 13 in the strip material cutting step. This contact force is controlled in particular by means of a predetermined torque delivered to the roller 10 by the motor member 11.

[0055] To this end, the tilting arm 21 carries at one end of the blade 20 a stop member 24, protruding with respect to the footprint of the roller 10. The stop member 24 is adapted to abut, in the cutting position of the blade 20, an abutment member 14 in turn protruding from the roller 10 at the border of the cavity 12. In the illustrated case, the stop member 24 consists of an appendage that extends transversely to the blade 20. However, it is possible to provide for the stop member to be made differently, for example by a simple lengthening of the blade 20 beyond the footprint of the roller 10.

[0056] The abutment member 14 associated with the unwinding roller 10 is arranged proximal with respect to the second head. The stop member 24 associated with the blade 20 is arranged so as to protrude longitudinally with respect to the roller 10, when it is in the cutting position, from the side of the second head, so as to engage the abutment member 14 associated with the roller 10.

[0057] Preferably, the strip material unwinding roller 10 comprises suction means 15 arranged upstream of the cavity 12, according to the direction of rotation of the roller 10 itself, adapted to retain said strip material during the cutting step (see fig. 6).

[0058] The arrangement of the suction means 15 on the strip unwinding roller 10 upstream ensures that the strip wound on the roller is fixed to the outer surface thereof, generating a surface tension of the strip such as to guarantee the cut by effect of the reciprocal actuation of the blade 20 and the counter-blade 13.

[0059] Preferably, said suction means 15 comprise a plurality of holes. Preferably, said plurality of holes is suitably connected to an air suction device. Advantageously, said air suction device can be powered by the motor member. Alternatively, the power supply of the air suction device may be external.

[0060] The operation of the apparatus for cutting strip material can be easily understood from the following description.

[0061] During the step of feeding the strip material to the machine, the strip material unwinding roller 10 is brought into rotation, at an adjustable speed, by the motor member 11 , so as to allow the unwinding of the same strip material. The strip material, coming for example from a relative reel, is unwound on the roller 10 and is fed to subsequent parts of the machine.

[0062] In this step the blade 20 carried by the tilting arm 21 is stationary in the rest position, suitably spaced from the roller 10 (see figures 6 and 7).

[0063] When the cutting of the strip material is required, the slowing of the roller 10 is commanded while, in a suitable phase relationship, the tilting arm 21 starts the angularrotation so as to bring the blade 20 into the cutting position in which the same blade 20 engages the cavity 12 of the roller 10 (see figures 8 and 9).

[0064] At the moment when the stop member 24 carried by the tilting arm 21 comes into contact with the abutment member 14 protruding from the roller 10, the roller 10 is stationary and the blade 20 starts cutting the strip material by interacting with the counter-blade 13. In particular, during this step, the cutting point shifts progressively along the blade 20 pressed against the counter-blade 13 (see figures 10 and 11).

[0065] It should be noted that, during the cutting step, the thrust exerted by the abutment member 14 protruding from the roller 10 on the stop member 24 carried by the tilting arm 21 , due to the action of the torque delivered by the motor member 11 , ensures that the correct contact force is present between the blade 20 and the counter-blade 13.

[0066] At the moment when the cutting of the strip material is completed, the cutting movement impressed on the blade 20 stops and the tilting arm 21 starts the return travel into the rest position. The sliding of the strip material to be fed to the machine on the roller 10 then resumes.

[0067] The apparatus according to the present invention achieves the object of optimally operating the cutting of strip material in the machines that use such strip material for manufacturing or packaging products.

[0068] In particular, this result is obtained thanks to the inventive idea of performing the cutting of the strip material on an unwinding roller on which the same strip material to be cut slides, by means of a blade which is configured to operate the cutting in combination with a counter-blade housed inside a cavity of the roller.

[0069] According to a prerogative of the invention, the contact force acting between the blade and the counter-blade is controlled, in the cutting step, by means of the action exerted by a torque delivered by the motor member of said unwinding roller.

[0070] Preferably, the torque around the axis of rotation is applied to the roller by the motor member responsible for driving the rotation of the roller itself.

[0071] This allows to ensure that the cutting point moves progressively along the blade while keeping the blade and counter-blade pressed against each other with a controlled force. This controlled force is ensured with precision by means of the force delivered by the electric motor, preferably of the brushless type.

[0072] The apparatus described by way of example is susceptible to numerous modifications and variations according to different needs.

[0073] In the practical implementation of the invention, the materials employed, as well as the shape and sizes, may be any according to requirements.

[0074] Where technical features mentioned in each claim are followed by reference marks, such reference marks have been included for the sole purpose of increasing the understandingof the claims and consequently they do not have any limiting value on the scope of each element identified by way of example by such reference marks.

Claims

1. An apparatus for cutting strip material, comprising- a strip unwinding roller (10) configured to be rotatably driven by a motor (11) about an axis of rotation (X), so as to unwind a strip to be cut and having on its outer surface a cavity (12) substantially radial and extending parallel to said axis of rotation (X);- a blade (20) configured to be driven with reciprocating motion on a plane substantially radial to said strip unwinding roller (10) so as to operate a cut of the strip at said cavity (12);- a counter-blade (13) arranged inside said cavity (12) of the strip unwinding roller (10), said blade (10) and said counter-blade (13) being configured to mutually cooperate during the cutting step;- means (14, 24) for controlling the contact force acting between said blade (20) and said counter-blade (13) during the strip cutting step, so as to ensure a correct contact force between blade and counter-blade.

2. The apparatus of claim 1 , wherein said blade (20) is configured to be driven by a tilting arm (21 ) between a rest position, spaced from said strip unwinding roller (10), and a cutting position in which the blade (20) engages said cavity (12) of the strip unwinding roller (10).

3. The apparatus of claim 2, wherein said tilting arm (21 ) is configured to be rotatably driven by a motor member (22) about an axis (Y) of said arm (21 ), preferably parallel to the axis (X) of rotation of the roller (10).

4. The apparatus of any one of the preceding claims, wherein said means (14, 24) for controlling the contact force acting between said blade (20) and said counter-blade (13) comprise a stop member (24) associated with said blade (20) and adapted to abut, in the cutting position, an abutment member (14) associated with said strip unwinding roller (10).

5. The apparatus of claim 4, wherein said abutment member (14) is stressed, during cutting, by the thrust action against said stop member (24) exerted by a torque delivered by the motor member (11 ) of said roller (10).

6. The apparatus of claims 4 or 5, wherein said stop member (24) comprises a portion protruding from an end of said tilting arm (21 ) of the blade (20).

7. The apparatus of any one of the preceding claims, wherein said counter-blade (13) has a respective cutting edge provided with a cutting corner located inside said cavity (12).

8. The apparatus of any one of the preceding claims, wherein said blade (20) has a respective cutting edge arranged inclined with respect to the axis of rotation (X) of the strip unwinding roller (10), so as to progressively engage said counter-blade (13) while cutting the strip.

9. The apparatus of any one of the preceding claims, wherein said cavity (12) extends over the entire width of the roller.

10. The apparatus of any one of the preceding claims, wherein it further comprises suction means (15) arranged on the outer surface of the strip unwinding roller (10), preferably at least upstream of said cavity (12) according to the direction of rotation of said roller (10).

11. A method for cutting strip material, comprising the steps of a. arranging a strip unwinding roller (10) adapted to be rotatably driven around an axis of rotation (X), so as to unwind a strip to be cut, wherein said roller (10) has on its outer surface a cavity (12) substantially radial and extending parallel to said axis of rotation (X), wherein said roller (10) also has a counter-blade (13) arranged inside said cavity (12); b. arranging a blade (20) external to said roller (10) and configured to be driven with reciprocating motion on a plane substantially radial to said strip unwinding roller (10) so as to operate a cut of the strip at said cavity (12); c. feeding said strip material to said strip unwinding roller (10) by rotatably driving said roller (10); d. stopping said strip unwinding roller (10) to perform the cutting of said strip material; e. driving the shift of said blade (20) to bring it into contact with said counter-blade (13) so as to perform the cutting of the strip material interposed between said blade (20) and said counter-blade (13); and f. driving means (14, 24) for controlling the contact force acting reciprocally between said blade (20) and said counter-blade (13) during the strip material cutting step, said step of f. driving control means (14, 24) being carried out at the same time as step e. of driving the shift of said blade (20).

12. The method of claim 11 , wherein said blade (20) has a respective cutting edge arranged inclined with respect to the axis of rotation (X) of the strip unwinding roller (10) at least during the step of e. driving the shift of said blade (20) so as to progressively engage said counter-blade (13) with the strip material interposed between them.

13. The method of claim 11 or 12, wherein said blade (20) is movable with respect to said roller (10) between a rest position, spaced from said strip unwinding roller (10) during the step of c. feeding said strip material, and a cutting position in which the blade (20) engages said cavity (12) of the strip unwinding roller (10) during the steps of d. stopping the roller (10), e. driving the shift of the blade (20) and f. driving the force control means (14, 24).

14. The method of claim 13, wherein said step of f. driving means (14, 24) for controlling the contact force acting between said blade (20) and said counter-blade (13) provides forf1 . bringing a stop member (24) associated with said blade (20) to abut, in said cutting position of the same blade (20), an abutment member (14) associated with said strip unwinding roller (10), and at the same time in said cutting step, and f2. operating a mutual controlled thrust force between said abutment member (14) and said stop member (24).

15. The method of claim 14, wherein said step of f2. operating said controlled thrust of the abutment member (14) against said stop member (24) is made by applying a torque around the axis of rotation (X) of said strip unwinding roller (10).

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