Abstract:
A cutter arrangement for automatically trimming flat products, such as leaflets, magazines and books transported along a horizontal path includes a clamping mechanism positioned along the path for clamping the products, respectively, during a trimming operation. A counter-knife is fixedly positioned above the horizontal path in a location corresponding to the position of the clamping mechanism and has a cutting edge. An up and down movable knife is coordinated with the clamping mechanism and positioned below the horizontal path beneath the counter-knife. The movable knife has a cutting edge for cooperating with the cutting edge of the counter-knife during an upward movement of the movable knife for trimming a respective one of the flat products clamped by the clamping mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Priority is claimed with respect to application No. 98810206.7 filed in the European Patent Office on Mar. 11, 1998, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a cutter arrangement for automatically trimming of flat products, such as leaflets, magazines and books, wherein the arrangement includes one or more up and down movable knives, a clamping bar and a fixedly installed counter-knife associated with each cutting knife, and comprising a transporting device for the continued transport of the leaflets, magazines and books. 
     Cutters of this type have long been known and have generally proven effective in practical operations. The operating principle for such cutters is disclosed in the applicant&#39;s prior 1959 Swiss Patent No. CH-A-34 04 79. The cutter disclosed therein comprises an up and down movable cutting unit with three knives distributed over two cutting stations arranged one after another with respect to the movement direction of the leaflets, such that a frontal cut can be executed with one knife and that top and bottom cuts can respectively be executed with the other two knives. The cutting unit, the transporting device and movable end stops are connected to a joint drive mechanism. Despite modifications to individual parts of this cutter, the basic design has to date remained unchanged. Such cutters are also referred to as trimmers or automatic three side trimmers. They permit an automatic trimming even of thick paper products with a capacity of, for example, six copies per second. The cut performed by the knives is also called a scissoring cut and is executed in that the cutting knife moves above the cutting edge of the counter-knife. One advantage of this type of cut is the long service life of the knives, which is considerably longer when compared to a cutting with the aid of cutting strips. However, an exact knife guidance is required. In addition, two stations are absolutely necessary for trimming products on three sides. 
     With the aforementioned cutter, the force flow is comparably unfavorable and deformations cannot be avoided. The control movements are furthermore complicated and only a comparably light press-down force is possible. Finally, accessibility is limited and lubrication is very involved. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a cutter of the aforementioned type, which avoids the previously mentioned disadvantages, but is still operative and can be produced economically. 
     The above and other objects of the invention are accomplished in accordance with the invention by the provision of a cutter arrangement for automatically trimming flat products, such as leaflets, magazines and books transported along a horizontal path, comprising: a clamping mechanism positioned along the path for clamping the products, respectively, during a trimming operation; a counter-knife fixedly positioned above the horizontal path in a location corresponding to the position of the clamping mechanism and having a cutting edge; and an up and down movable knife coordinated with the clamping mechanism and positioned below the horizontal path beneath the counter-knife, the movable knife having a cutting edge for cooperating with the cutting edge of the counter-knife during an upward movement of the movable knife for trimming a respective one of the flat products clamped by the clamping mechanism. 
     According to a further aspect of the invention, the cutter arrangement includes at least first and second cutting stations, with each station comprising at least one clamping mechanism, counter-knife and movable knife arranged as above, with one of the first and second cutting stations performs a cutting operation transverse to a direction of movement of the products along the horizontal path and the other of the first and second cutting stations performs a trimming operation transverse to the direction of movement of the products along the horizontal path, and a transport mechanism is provided to transports the products from the first cutting station to the second cutting station. 
     The object of the invention is thus achieved in that the up and down movable knives are arranged underneath the counter-knives so that they can be moved from below against the counter-knives to perform the trimming operation. That is, in contrast to heretofore state of the art devices, the cutting knives according to the invention are not arranged above the fixedly installed counter-knives, but below them. This results in the following, numerous advantages: 
     All movable parts can be arranged inside an oil bath, without the danger of dirtying the products through oil dripping down. Consequently, the knife guides can be lubricated optimally with oil, which results in a considerable reduction in wear and tear as well as knife play. 
     The counter-knives can be pivoted away easily with the aid of a support, thereby making it easier to gain access to the knives for replacement and also reducing the danger of injury. 
     An adjustment of the counter-knives relative to the cutting knives is much easier than has been possible in that the support is displaced horizontally. 
     The cutting knives can be removed easily from above, without the danger of sustaining an injury. 
     Since no cutting forces are transmitted via the frame, a considerably higher clamping force is possible, owing to a more direct force flow with a simultaneously lighter machine frame. 
     Since a knife yoke, which heretofore has always been arranged above the transport belts, is omitted, a better view of the transport during the cutting operation is possible, which consequently permits a quicker and easier adjustment. 
     Due to the fixed arrangement of the counter-knives above the product, the thickness of the products does not affect the position or height of the upper belt. The device for adjusting the upper belt height consequently can have a simpler design. 
     Dangerous compression locations in the region of the end stops as well as the cutting transport can be secured locally, so that it is possible to make an adjustment without an additional protective cover or risk of injury. 
     Omitting the yoke for the knives furthermore has the advantage that the design height can be reduced, e.g. by 300 mm. 
     Finally, a much simpler design can be realized for a vacuum duct used to remove the trimmings, making it possible to eliminate the comparably large cover which was previously necessary. 
     Additional advantageous features will be apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     FIG. 1 is a schematic vertical section, in a direction of transport of the flat product, through a cutter of a first cutter station according to the invention, wherein individual parts are left out to make the drawing easier to understand. 
     FIG. 2 is a schematic vertical section, transverse to the direction of transport of flat product, through the cutters of a second cutter station according to the invention. 
     FIG. 3 is an additional schematic vertical section, in the direction of transport of product, through a cutter including the cutter drive mechanism according to the invention. 
     FIG. 4 is a partial section along the line III—III of FIG.  3 . 
     FIG. 5 is a schematic representation of a partial section through the cutter according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, there is shown a cutter  1  according to the invention with a belt conveyor  13  feeding feed flat products  41  along a horizontal path to be cut individually. The transporting direction is indicated by arrow  7 . FIG. 1 shows a product  41  approaching cutter  1  with its back  41   a  forward to the cutter. A transporting device  6 , which includes lower belts  11  and upper belts  12  deflected via rollers  10 , is provided for the transport of products  41  inside cutter  1 . Transporting device  6  transports products  41  from a first cutting station to a second cutting station. In the first cutting station, a frontal cut is respectively executed by a cutting unit  14  shown in FIG.  1 . In the second cutting station, a top cut and a bottom cut are respectively executed with two additional cutting units  14 ′. These additional cutting units  14 ′ are shown in FIG.  2 . The cutting units  14  and  14 ′ have essentially the same design. However, the cutting unit  14  extends crosswise to the transporting direction  7 , whereas the cutting units  14 ′ are arranged parallel to the transporting direction  7  and at a distance from each other. Each cutting unit  14  and  14 ′ is respectively coordinated with a fixed counter-knife  5 . Of course, transport device  6  is matched to the transport on belt conveyor  13 . End stops  58  (see FIG. 5) and means for aligning products  41 , which are not shown here, are provided for the two aforementioned cutting stations. As shown in FIG. 2, brushes  36 , which rest on the top of products  41 , are provided to prevent the products  41  from dropping back at the end stops. 
     It is essential that the respective counter-knives  5  are secured immovably in a holder, such that their cutting edges  42  respectively face downward and are located above the product  41  to be cut. The counter-knives  5  are thus respectively arranged above a cutting unit  14  and  14 ′. In this way, the cutting units  14  and  14 ′ execute an upward directed cut, and the products  41  are respectively pushed with their top sides  43  against the counter-knives  5 . FIG. 1 shows this arrangement for the frontal cut. As can be seen, the cutting edge  42  of counter-knife  5  is arranged above and the cutting edge  9  of cutting unit  14  is arranged below. For the frontal cut, the cutting edge  9  can be moved upward until it overlaps with the cutting edge  42  and then back again. In FIG. 1, the frontal cut has already been executed on the product  41 ′ and, following the complete withdrawal of the cutting edge  9 , another product  41  is shown being supplied by belt conveyor  13  to transport to effect a frontal cut by cutter  14 , after which transport device  6  conveys the product to the next cutting station for top and bottom cuts by cutters  14 ′. 
     The cutting units  14  and  14 ′ each have respectively one bearing housing  30 , which forms a tub with an oil-filled interior space or chamber  39 . This inside space  39  contains respectively one knife  3  and one clamping bar  4 . Each knife  3  is coordinated with a clamping bar  4 . Both can be moved vertically up and down, respectively in the directions of double arrow  44 . 
     FIGS. 3 and 4 schematically illustrate a drive for the lifting movement of a knife  3 , which in this case performs a top cut. A cam disk  17  is positioned inside a machine frame  31  and is driven by means of a main shaft  19  in the direction of arrow  45 . In order to carry out a swing cut by a crank-mechanism, a support  15  for knife  3  is positioned inside the machine frame  31 . In addition, support  15  is guided on a one-arm lever  23 , which can pivot to a limited degree around a shaft  24 , rigidly secured to the frame, and is connected with a revolving joint  25  to support  15 . A further lever  16 , designed as a two-arm angle lever, engages with the aid of a cam roller  20  in a control cam  18  of cam disk  17 . Lever  16  is positioned such that it can pivot around a fixed arbor  21  on bearing housing  30  for machine frame  31  and is connected via a joint  22  to support  15 . FIG. 3 shows the upper position of knife  3 . Control cam  18  is designed such that when cam disk  17  turns farther in the direction of arrow  45 , the lever  16  is pivoted clockwise around fixed arbor  21 . Knife  3  with the cutting blade  8  is thereby moved downward to a specified lower position. Following a rotation of 180° of the cam disk, lever  16  is pivoted counter-clockwise and the knife  3  is moved upward again to execute the cut. Knife  3  is thus moved up and down continuously to execute the swing cut movement. A cut is made during each vertical upward movement, wherein cutting edge  9  cooperates with the cutting edge  42  of counter-knife  5  and overlaps this knife. The moving parts of the knife drive, meaning in particular levers  16  and  23  and cam disk  17  in this case, are positioned in the oil inside chamber  39 . Since cutting knives  8  are located above the oil bath, a soiling of products  41  through dripping oil is not possible. The drive for clamping bar  4  can essentially be the same as the drive for knives  3 , explained above with the aid of FIG.  3 . However, it is critical that respective knife  3  and clamping bar  4  can be configured as a compact cutting unit  14  or  14 ′. Clamping bars  4  are controlled such that when executing a cut, products  41  are first pressed against the counter-knife  5  or the counter-knives  5  and are subsequently trimmed. A yoke between the cutting units  14  and  14 ′ is not needed. As a result of this, a very short and positive force flow is possible for the lifting. 
     According to FIG. 1, main shaft  19  is connected by a cross coupling  60  to a shaft  61 , which engages fixedly connected in a hub  62  of cam disk  17  of cutting unit  14 . The cutting units  14  and  14 ′ thus are driven jointly. However, individual drives are also conceivable. 
     Counter-knives  5  are respectively positioned in a support  32 ,  33 . Each of the supports can be displaced horizontally in the directions of double arrow  34  and thus can be adjusted precisely, relative to the cutting knives  8 . A shown in FIG. 5, support  32  has an elongated aperture  50 , into which a shaft  51  that is rigidly secured to the frame engages. In addition, supports  32  are attached to frame  31  so that together with the counter-knife they can pivot away from blade  9 , respectively, in the direction of arrow  35 . As a result of this, the knives  8  can be accessed easily for replacement. Supports  32  furthermore cover the cutting locations and protect against an injury. 
     Owing to the fixed arrangement of counter-knives  5  above products  41 , the thickness of products  41  does not influence the position of upper belts  12 . Consequently, upper belts  12  do not have to be vertically adjustable to take into account the thickness of products  41 , as the case has been in the past. Thus, the device for the vertical adjustment of upper belts  12 , which is required to interrupt the transport, can have a comparably simple design. Devices for the vertical adjustment of the upper belts, as well as suitable belt drives and controls, are known to the person skilled in the art and are therefore not explained in further detail here. 
     In order to adapt to the thickness of products  41 , the lower belts  11  on a device (not shown here) are positioned such that they can be vertically adjusted in the direction of double arrow  47  (FIG.  1 ). Such adjustment devices are known per se to the person skilled in the art and are therefore not here explained further. However, separating this adjustment option from the lift of upper belts  12  represents a considerable simplification of the design. Until now, both functions had to be integrated into upper belts  12 . 
     As shown in FIG. 5, each cutting knife  8  is attached with a fastening screw  52  to its support  15 , so that the cutting knife can be replaced. Fastening screw  52  engages in a threaded bore  53  of cutting knife  8  and its head is supported on a washer  54 . In order to replace cutting knife  8 , support  32  is pivoted to the position shown in FIG.  5  and fastening screw  52  is unscrewed from thread bore  53  until cutting knife  8  can be lifted off knife support  15 . A new cutting knife  8  can be easily fastened on support  32  in the same way by using a screw  52 . Support  32  also has a vacuum duct  55 , which extends along the cutting knife  8  and is connected to a vacuum device not shown here. A plate  56  is attached to bearing housing  30  to seal duct  55 . If support  32  is fastened with a tension screw  57  on bearing housing  30 , as shown in FIG. 2, the material trimmed off during each cutting operation, which is not shown here, will be deposited in duct  55  and removed via this duct. 
     The invention has been described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art, the changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications as to fall within the true spirit of the invention.