Abstract:
A system for engaging and locking the cartridge on the body of a cutter holder adapted to equip machines for the industrial cutting of flexible laminates, comprising a slider with a dovetail profile on the lower portion of the cutter holder body, the head portion of the cartridge being provided with a slot with a profile complementary to the profile of the slider for engagement of the cartridge on the cutter holder body, elements for locking the cartridge on the cutter holder body, and a lever for actuating locking elements, which comprise at least one movable element, which applies a symmetrical force with an upward traction component on both sides of the complementary profile of the slot.

Description:
The present invention relates to a cutter holder adapted to equip machines for the industrial cutting of flexible laminates, and discloses a system for coupling the cartridge of the cutter to the cutter holder body. 
   More specifically, the invention relates to a mechanism which is integrated in the body of the cutter holder and allows the engagement and locking of the cartridge on the body of the cutter holder, and to the corresponding means provided on the cartridge which cooperate with such mechanism. 
   BACKGROUND OF THE INVENTION 
   Modern systems for industrial cutting comprise several motorized cutting systems, each of which has a plurality of cutters arranged side-by-side and actuated simultaneously by devices which can have an electromagnetic, pneumatic or other operating principle and operate continuously even for three eight-hour shifts, seven days a week, as in the case of paper industries. Currently, scissor-type or pressure-type devices are mostly used to cut laminates, for example paper, plastics, aluminum, two-part elements, and fibers of any sort, from non-wovens to carbon fiber. These devices use a circular cutter, which is mounted on an appropriate cutter holder, which acts by lateral contact with a complementary rotating cutter, in the case of scissor-type cutting, or directly by pressing on the material to be cut, which advances on a contrast roller, in the case of pressure cutting. 
   A cutter holder of this type is constituted generally by a fixed part, which is installed on the supports, which in turn are fitted on a sliding guide of the industrial cutting machine, which is known as cutter holder body, and by a movable part, known as cartridge, on which the circular cutter is fitted. Such cartridge is engaged detachably on the body of the cutter holder, which is provided with a suitable coupling, and must be removed from it whenever it is necessary to perform maintenance on the blade of the cutter or replace it. Since the cutter holder and the cartridge must work as if they were monolithic with each other, in order to ensure precise and constant execution of the cut over time, the mechanical stresses to which the cutter holder is subjected must not be discharged asymmetrically onto said coupling, on penalty of higher wear of the device and also of the occurrence of dangerous weaknesses. For this reason, the coupling of the cartridge on the cutter holder must be conceived and provided so as to be at once durable and rational for the user, who by means of simple and repeatable actions, and in full safety, must be able to extract the cartridge and reinsert it subsequently, fixing it firmly to the cutter holder body. 
   Various kinds of coupling of the cartridge on the cutter holder body are known. EP-0562454 discloses a cutting unit for the longitudinal cutting of flexible materials, such as for example paper strips, which is provided with means which allow rapid replacement of the blade holder head. Such head is connected to a vertical pivot, which enters the body of the blade holder and around which said head can turn up to 180°, i.e., perform a reversal. The blade holder head is provided with a T-shaped element, the longer external side of which has a lower portion which receives and locks the arm of the fork, while the shorter side and a side which is adjacent and perpendicular thereto make contact and are locked by means of a screw. By unscrewing such screw, the blade holder head can be removed. Although such a mechanism fully achieves the intended aim, it has certain limitations. First of all, it requires the user to loosen a screw, an operation which is not exactly fast, and especially to act manually in the immediate vicinity of the blade of the cutter, thus exposing himself to the risk of injury, although a housing for partial protection is provided on the circumference of the blade in the inactive condition. Moreover, the head reversal operation does not occur by reversing the position of the head but by way of the rotation of the stem to which the cartridge is coupled, and this occurs by means of appropriate controls located on the upper portion of the cutter holder body. 
   U.S. Pat. No. 6,732,625 discloses a cutter holder in which the engagement and removal of the cartridge occur by means of a slider with a dovetail profile, which is provided on the body of the cutter holder and on which the cartridge is engaged horizontally, a slot provided with a complementarily shaped profile being provided for this purpose on the head portion of the cartridge. A locking device is also present which can be activated and deactivated manually and consists of a lever provided with a cam, which, when turned about a pivot, pushes with the cam in an oblique direction a locking bar, which like a wedge locks the cartridge on the cutter holder. This mechanism simplifies the removal and reengagement of the cartridge and also allows to turn through 180° the blade of the cutter simply by extracting the cartridge and reinserting it in the inverted position. However, the resulting type of locking is not symmetrical on both sides of the dovetail slider of the cartridge. Moreover, the contact between the pneumatic ducts of the cutter holder body and of the cartridge, which are required in order to allow the partial approach and full approach of the blade, might not maintain a perfect coupling, since a uniform contact pressure between the corresponding horizontal surfaces of the body of the cutter holder and of the cartridge head portion is not provided. 
   SUMMARY OF THE INVENTION 
   The aim of the present invention is to provide a system for engaging and locking the cartridge on the cutter holder body which allows a symmetrical distribution of forces on both sides of the head portion of the cartridge. 
   Within this aim, an object of the present invention is to provide an engagement and locking system in which said locking is ensured by an upward traction force which acts on the head portion of the cartridge, thus ensuring better retention of the joints of the ducts of the pressurized fluid. 
   Another object of the present invention is to provide an engagement and locking system in which said locking ensures high rigidity in order to withstand the vibrations produced during cutting. 
   Another object of the present invention is to provide an engagement and locking system which allows high repeatability of the positioning of the cartridge, without the mutual positioning of the cartridge and the cutter holder body undergoing any alteration over time. 
   A further object of the present invention is to provide an engagement and locking system which is safer, since even in case of failure to operate of the locking mechanism, once the cartridge has been engaged it can no longer disengage autonomously. 
   A still further object of the present invention is to provide a system for engaging and locking the cartridge on the body of the cutter holder which is provided with actuation elements which are practical and absolutely rational for the operator, so as to help to reduce the probability of human error during setup, start-up and maintenance of the cutting lines. 
   This aim and these and other objects which will become better apparent hereinafter are achieved by a system for engaging and locking the cartridge on the body of the cutter holder according to the present invention, which comprises the slider provided with the dovetail profile provided on the lower portion of the body of the cutter holder, the head portion of the cartridge provided with the slot with a profile which is complementary with respect to the profile of said slider for the engagement of said cartridge on the body of the cutter holder, means for locking the cartridge on the body of the cutter holder, and a lever for actuating said means, wherein said means for locking the cartridge on the body of the cutter holder comprise at least one movable element, which applies a symmetrical force with an upward traction component on both sides of said profile which is shaped complementarily with respect to said slot. 
   Preferably, said head portion of the cartridge has seats which are provided on the vertical walls of the slot and are symmetrical with respect to both vertical planes of symmetry of said slot, so as to allow the engagement of the cartridge in two positions, one rotated through a straight angle with respect to the other. 
   Said means for locking the cartridge on the body of the cutter holder further comprise a crank and a link, which are mutually connected by means of a first hinge, the crank being provided with a seat in which said lever is engaged and being coupled to a portion of said slider by means of a second hinge, which lies in an intermediate position between the seat and said first hinge. 
   Preferably, the at least one movable element is a transverse pivot which is rigidly coupled to the link and has a horizontal axis which is perpendicular to the axis of said link. 
   Preferably, a one-way mechanism is provided -which comprises an L-shaped lever which has a button and an end portion and is hinged to the front portion of the slider of the body of the cutter holder by means of said second hinge. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein: 
       FIG. 1  is a front elevation view of a cutter holder provided with the engagement and locking system according to the present invention; 
       FIG. 2  is a side elevation view of a portion of the cutter holder with the lever raised in the release position; 
       FIG. 3  is a sectional view of  FIG. 2 , illustrating the details of the locking mechanism; 
       FIG. 4  is a side elevation view of a portion of the cutter holder, with the lever lowered in the locking position; 
       FIG. 5  is a sectional view of  FIG. 4 , illustrating the details of the locking mechanism; 
       FIG. 6  is a sectional view of the locking mechanism, illustrating the details of the one-way mechanism. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  illustrates a cutter holder, in which it is possible to distinguish the body of the cutter holder  1  and a removable cartridge  2  on which a cutter  3  is mounted. A dovetail slider  4 , which is symmetrical on the right and left sides, is provided on the lower horizontal plane of the body of the cutter holder  1 . The head portion  5  of the cartridge is provided with a slot  6 , the profile of which is complementary to the profile of the dovetail slider  4 , which allows the sliding engagement of the cartridge  2  on the body of the cutter holder  1 , locking its degrees of freedom related to rotation about the vertical axis and translational motion along the vertical axis. With reference to  FIGS. 2 and 3 , on the side walls of the slider  4  there are symmetrically arranged stop pins  7 , which are designed to stop the sliding of the slot  6  on the slider  4  in the point where the body of the cutter holder and the cartridge are mutually positioned correctly. For this purpose, the vertical walls of the slot  6  are provided symmetrically with respect to seats  8 ,  8 ′. Said seats, two for each side, are symmetrical with respect to both vertical planes of symmetry of the slot  6 . This refinement in fact allows to fit the cartridge on the body of the cutter holder from either of the two insertion sides of the slot  6 , and therefore obtain a rotation of the cutter through 180° about the vertical axis. The seats  8 ,  8 ′ have a horizontal base, a vertical wall and an oblique upper wall, so as to have the minimum distance with respect to the base in the innermost point of the seat. Once the cartridge has been inserted in the cutter holder body, therefore, the pins  7  abut against said oblique wall of the seats  8 . 
     FIG. 2  shows that a lever  9  for actuating the locking mechanism is lifted. In this position, the lever  9  is in neutral: in other words, the cartridge  2  is inserted in the cutter holder body  1  but is not locked. By turning downward the actuation lever  9 , as can be seen in  FIG. 4 , the cartridge is also locked on the body of the cutter holder. 
     FIGS. 3 and 5  clearly show the elements that compose the locking mechanism. The actuation lever  9 , not shown, is interlocked in a seat  10  of a crank  11 . At the opposite end of the crank  11  with respect to the seat  10  a first hinge  12  is provided, which connects the crank  11  to a link  13 . The crank  11  is rigidly coupled to the front and central portion of the dovetail slider  4  by means of a second hinge  14 , which is in an intermediate position between the seat  10  and the first hinge  12 . The link  13  in turn is constituted by a head portion  15 , which is pivoted to the crank  11 , and by a rod  16 . The rod  16  is rigidly coupled to the head portion  15  by means of a threaded coupling. Proximate to the other end of the link  13  there is a transverse pivot  18 , the axis of which is horizontal and perpendicular with respect to the axis of the link  13 . The pivot  18  is provided, for this purpose, with a central hole, the axis of which is directed like the axis of the link  13 , such as to allow the sliding insertion of the link  13 . A first spring  19  with a high elastic constant is interposed between the pivot  18  and the head portion  15  of the link  13 . The first spring  19  contrasts the sliding of the transverse pivot  18  on the rod  16  of the link  13 . Finally, the rod  16  has a flange  17  on which the transverse pivot  18  abuts and a subsequent end pin  20 , which is arranged after the transverse pivot  18  and the flange  17  and on which a second spring  21 , having a low elastic constant, engages. The second spring  21  allows the actuation lever  9  to keep, when in the neutral condition, a position of equilibrium in which it is raised. The second spring  21  abuts, for this purpose, against the flange  17  and with a vertical wall of the dovetail slider  4  at the opposite end with respect to the pin  20  on which it engages. 
   With reference to  FIGS. 4 ,  5  and  6 , when the operator turns the lever  9  downward, he turns the crank  11 , which is rigidly coupled to the lever  9 , about the second hinge  14 . The first hinge  12  therefore moves forward and upward, as shown clearly in  FIGS. 4 and 5 , and the link  13  advances initially rigidly with the transverse pivot  18 , overcoming the elastic force of the second spring  21 , which is compressed. The transverse pivot  18 , advancing along slots provided on the sides of the slider  4 , ends its stroke when it encounters the corner between said oblique wall and the vertical wall of the seats  8 ′ provided on the vertical walls of the slot  6  of the cartridge  2 . The pivot  18  therefore stops and the link  13  continues to advance by sliding inside it, and simultaneously the advancement of the head portion  15  compresses the first spring  19 . Due to a physical law related to inclined planes, there is a component which is directed vertically and upward of the force of contact between the transverse pivot  18  and said oblique walls of the seats  8 ′, which is due to the compression of the first spring  19 . Thanks to this force, the cartridge  2  is fixed to the body  1  of the cutter holder by a resultant force which has a traction component which is indeed directed upward. The lever  9 , when lowered, remains in this position of equilibrium because, as shown by  FIG. 5 , the first hinge  12  lies above the second hinge  14  and the elastic return force applied by the first spring  19 , which is directed like the axis of the link  13 , generates a torque which tends to keep the lever  9  lowered. 
   In a system of this type, the first spring  19  with rigid elastic constant is capable of giving optimum rigidity to the coupling, such as to withstand the vibration produced by the cutter  3  during cutting. 
   Should the operator accidentally forget to lower the lever  9  for actuating the locking mechanism, the cutter would begin to cut, and due to the contact forces between the blade of the cutter and the complementary cutter, the cartridge might disengage autonomously. In order to avoid an accident scenario of this type, the engagement and locking system according to the present invention is also provided with a one-way mechanism, which does not allow the cartridge  2  to disengage autonomously from the body of the cutter holder  1  if the lever  9  has remained raised. This one-way mechanism, shown in detail in  FIG. 6 , comprises a L-shaped secondary lever  22 , which is pivoted to the front portion of the slider  4  of the body  1  of the cutter holder by means of the second hinge  14 , which retains the crank  11 , with respect to which the lever  22  remains on the right. A scissor-like spring  23 , by pressing on on the horizontal side of the lever  22 , generates a clockwise torque, with respect to  FIG. 6 , which keeps a button  24  of the lever  22  raised, making the end portion  25  of the lever  22  protrude from the sliding plane of the slider. This end portion abuts against the front vertical wall of the head  5  of the cartridge  2 , preventing its accidental disengagement. 
   It is evident that an engagement and locking system according to the present invention can ensure a distribution of forces which is absolutely symmetrical on both sides of the head of the cartridge, and further that this distribution of forces has a vertical upward traction resultant, which further contributes to improving the contact between the ducts of the pressurized fluid of the body of the cutter holder and the ducts inside the cartridge. 
   Any variations in the shape, material, number or overall arrangement of the elements which characterize the engagement and locking system do not alter in any way the functional characteristics of the invention, as claimed hereinafter. 
   The disclosures in Italian Patent Application No. MI2005A000358 from which this application claims priority are incorporated herein by reference.