# Patent

## Title
Rotary cutting apparatus comprising a cutter drum and an anvil drum

## Abstract

A rotary cutting apparatus includes a cutter drum having at least one cutting member and an anvil drum having a rotary axis, arranged in a cutting relationship to one another, and a pressure actuating device for subjecting pressure on said cutting member in relation to the anvil drum. The pressure actuating device includes a pair of levers rotatable about at least one hinge having a horizontal axis. The horizontal axis is parallel to but non-concentric with the rotary axis. In addition, a frame supports the cutter drum and the anvil drum in a rotatable relationship. The pair of levers are releasably connected to the bearing housing, respectively, in such a way that the anvil drum is allowed to be removed from the frame.

## Background
FIELD OF THE INVENTION
The present invention generally relates to a rotary cutting apparatus. More particularly, the present invention pertains to a rotary cutting apparatus comprising a cutter drum having at least one cutting member and an anvil drum having a rotary axis, arranged in a cutting relationship to one another, and a pressure actuating device for subjecting pressure on the cutting member in relation to the anvil drum.
BACKGROUND
U.S. Pat. No. 6,244,148 describes a rotary cutting apparatus including a cutter drum and an anvil drum, where a pressure actuating device applies pressure to the cutting member in relation to the anvil drum. The apparatus described therein has significant drawbacks in that it is costly and cumbersome to disassemble it for maintenance, e.g. for re-grinding the anvil drum. Another rotary cutting apparatus is described in U.S. Pat. No. 4,770,078, which suffers from the same drawbacks.
Japanese Unexamined Patent Publication No. 2001-300888 discloses a rotary cutting apparatus, which comprises a lever for subjecting pressure on the cutting member, but is cumbersome to disassemble, since the lever is directly connected to the roller bearing. Such connection generally requires shrink fit, or a least press fit, causing a very cumbersome disassembly for maintenance.
Accordingly, there is a need in the art to reduce the time and cost for performing maintenance of a rotary cutting apparatus.
SUMMARY
A first aspect of the invention pertains to a rotary cutting apparatus comprising a cutter drum having at least one cutting member. An anvil drum has a rotary axis and is arranged in a cutting relationship to the cutter drum. A pressure actuating device subjects pressure on the cutting member in relation to the anvil drum. The pressure actuating device comprises a pair of levers rotatable about at least one hinge having a horizontal axis. The horizontal axis is parallel to but non-concentric with the rotary axis, wherein a bearing housing is arranged on each axial side of the anvil drum. A frame supports the cutter drum and the anvil drum in a rotatable relationship, wherein the pair of levers are releasably connected to the bearing housing, respectively, in such a way that the anvil drum is allowed to be removed from the frame.



BRIEF DESCRIPTION OF THE DRAWING FIGURES
The accompanying drawings provide visual representations which will be used to more fully describe the representative embodiments disclosed herein and can be used by those skilled in the art to better understand them and their inherent advantages. In these drawings, like reference numerals identify corresponding elements.
FIG. 1A is a front view of a first variant of a rotary cutting apparatus having a frame.
FIG. 1B is a magnification in-part of FIG. 1A, parts of the frame being omitted.
FIG. 1C is a rear view of the frame shown in FIG. 1A, however in an open state.
FIGS. 2A and 2B are front and rear perspective views of a second variant of a rotary cutting apparatus.
FIG. 2C illustrates an open state of the frame shown in FIGS. 2A and 2B.
FIGS. 3A and 3C are front perspective views of a third variant of a rotary cutting apparatus.
FIG. 4A illustrates the anvil shown in FIGS. 1A to 3B.
FIG. 4B is a cross-section of the anvil shown in FIG. 4A.
FIG. 4C is a magnification in-part of FIG. 4A.
FIG. 5A illustrates the anvil shown in FIG. 4A provided with end caps.
FIG. 5B is a cross-section of the anvil with end caps shown in FIG. 5A.
FIG. 6 is a variant of the anvil and end caps shown in FIG. 5A.
FIG. 7 is a further variant of the anvil and end caps shown in FIG. 5A.



DETAILED DESCRIPTION
FIG. 1A shows a rotary cutting apparatus 2 comprising a frame 4 attached to a base 6 by means of screws 8. A rotary cutting device 10 is removably attached to the frame 4 by means of plates 12 securing cutter bearing housing 14 on either sides of a cutter drum 16 provided with at least one knife member 17.
An anvil 18 with an anvil drum 19 and having a substantially horizontal axis A-A (see also FIG. 4a) is arranged vertically above the rotary cutting device 10 and includes an axially peripheral surface 43 of the anvil drum 19.
A pair of levers 20 are rotatably arranged about a hinge 22, comprising an axle 23 journalled in bearings 24, the axle 23 having a substantially horizontal axis B-B and being attached to the frame 4 by means of screws 25a and a pair of L-shaped bars 25b, connected to a lid 26 of the frame by means of screws 25c. The lid 26 is connected to the frame 4 by means of four screws 26a, 26b, 26c, 26d (the latter being hidden).
The levers 20 are arranged on either sides of a vertical plane through the axis B-B of the anvil 18. Two pneumatic cylinders 27a are arranged substantially parallel to the hinge axis B-B and the rotational axis A-A and opposite to a vertical plane through the axis A-A. The cylinders 27a are adapted to co-operate with the levers 20, respectively, for turning them about the hinge 22. As can be seen in the Figures, the horizontal axis (B-B) of the levers is arranged, seen in a vertical plane, above the rotary axis (A-A).
FIG. 1B shows furthermore that the inter-connection of the jacks 27a with the levers 20 comprises a link 27b provided with double hinges 28a, 28b, respectively. The pneumatic cylinders 27a are adapted to apply a substantially vertical force on the levers 20, respectively, via the links 27b, resulting in a rotation about the hinges 22 such that the levers 20 will perform an arc-shaped movement.
The anvil 18 is provided with a bearing housing 30, on either sides of the anvil drum 19. Each bearing housing 30 is provided with a coaxial opening 32 for allowing access to the interior of the bearing housing 30, and with a screw 34 covering an oil filling hole 35 (see FIG. 4b). The bearing housing 30 is also provided with a radially directed threaded opening 36 (see FIG. 4a) for receiving a screw 38 in order to attach the bearing housing 30 to the lever 20.
During operation, the cylinders 27a will press the anvil drum 19 towards and against the knife member 17 of the cutter drum 16. Even though the levers 20 perform an arc shaped movement, it is so small that the movement of the anvil drum 19 towards and against the cutter drum 16 will be substantially vertical.
FIG. 1C shows the rotary cutting apparatus 2 in an open state for allowing removal and maintenance of the anvil 18. This has been performed by attaching a detachable handle 39 to one of the L-shaped bars 25b, loosening the screws 26a, 26b, 26c and 26d and turning the lid 26 about the hinge 22.
In the position shown, a lifting device (not shown) can be attached to the openings 32 of the anvil 18 for lifting it away from the frame 4. After attachment of the lifting device to the anvil 18, the screws 38 (see FIG. 1B) are loosened such that the anvil 18 is released from the levers 20.
Pneumatic cylinders have generally the characteristics that in the beginning of the movement of the piston, the force is not easily controllable, since the generated force will not be linear with respect to the applied pneumatic pressure in the cylinder. In order to overcome this problem, springs 39a are arranged to act on the end of the lever opposite to that of the hinge 22. The springs 39a will also counter balance the weight of the anvil 18, such that a minimum pressure is required for the anvil drum 19 to come into contact with the cutter drum 16 during use. The springs 39a will also prevent the anvil from colliding with the cutter drum 16, hereby avoiding damages of the knife member 17 and/or the axially peripheral surface 43 of the anvil drum 19.
FIGS. 2A and 2B show in front and rear perspective views of a second variant, according to which the anvil 18 is arranged underneath the cutter drum 16. In this embodiment, the cylinders 27a and the levers 20 are arranged underneath the anvil 18. The cylinders 27a thus subject a force directed substantially vertically upwards (see arrow) to the anvil 18 towards and against the knife member 17 of the rotary cutting device 10.
Also in this case springs 39a are provided for the same purpose as mentioned above.
The frame 4 forms an opening 4a, 4b on each side of a vertical plane through the axis A-A of the anvil 18.
Furthermore, the horizontal axis (B-B) of the levers is arranged, seen in a vertical plane, below the rotary axis (A-A).
As shown in FIG. 2C, the anvil 18 according to this variant is removed for service by placing a table or a wagon beneath the frame 4, unscrewing and removing the screws 38 for releasing the anvil 18 from the levers 20 and then moving the anvil 18 in a direction across the axis A-A through the frame opening 4a to the table or wagon. A lifting device now can be attached to the openings 32 of the anvil 18 for lifting it away for maintenance.
FIG. 3A to 3C show a third variant, according to which the anvil 18 and the levers 20 (omitted in FIG. 3B for better understanding) are arranged underneath the rotary cutting device 10, whereas the cylinders 27a are arranged above the anvil 18, in fact also above the cutting device 10, even though it would be possible to arrange the cylinders 27a at the same vertical level as the cutting device 10, i.e., beside it.
The piston rod 27b of the cylinders 27a are each provided with a holding member 27c, shaped for receiving a horizontal crossbar 70 at two separate horizontal positions. The crossbar is connected to a pair of vertical bars 72, each of which being connected to one of the levers 20. A pair of guiding members 27d for guiding constitute stop members for the piston rods 27b. The guiding members 27d are rotatably connected to the frame 4 by means of a hinge 27e. 
When the cylinders are moved upwardly, the anvil 18 will be moved towards and against the knife member 17 of the rotary cutting device 10, i.e., the anvil 18 will be subjected to a pulling force, as opposed to the force according to the first and second variants, according to which the applied force is a pressing force.
In this variant, the levers 20 are arranged on separate hinges 22a (hidden), 22b, each being provided with an axle 23a (hidden), 23b, the levers 20 being secured thereto by means of a nut 23c (hidden), 23d, respectively. The axles 23a, 23b are aligned with one another in order to form a common rotational axis B-B. The bearing housings 30 are provided with axially directed openings for receiving screws 40 in order to attach the bearing housing 30 to the lever 20.
Furthermore, the horizontal axis (B-B) of the levers is arranged, seen in a vertical plane, at about the same level as the rotary axis.
In FIG. 3C is shown how the anvil 18 is allowed to be removed for service. To start, the guiding members 27d are turned about the hinge 27e, allowing the piston rods to be retracted to a position not visible in the figure, i.e., inside the frame 4. The crossbar 70 is released from the holding members 27c, allowing the vertical bars 70 to be moved downwards (see arrow), in turn causing the levers 20 to turn downwards about the axis B-B. Then the screws 40, the nut 23d and the corresponding lever 20 are released and removed. The anvil 18 is now allowed to be pulled out from the frame along axis A-A.
The springs 39a have the same purpose as those shown in FIGS. 1A-2C.
FIGS. 4A and 4B show the anvil 18 with its anvil drum 19 and bearing housings 30. In FIG. 4B, the anvil drum 19 has been shown as solid with integrated axle 42. The axially peripheral surface 43 of the anvil drum is centered coaxially with the axis A-A during its manufacture. The drum 19 may however instead be hollow, e.g. in the form of a sleeve, attached to the axle 42, i.e., constituting a separate part.
The bearing housing 30 comprises an axially directed ring 44 with a radially (towards the axis A-A) directed annular protrusion 46, and an inner and outer cover 48, 50 in the form of an annular plate, respectively, together with the axle 42 defining a space 51 for a toroidal bearing 52a and an oscillating bearing 52b, to be arranged on the peripheral axial surface 42a (see FIG. 4C) of the axles 42, respectively, for avoiding constrainment and to take up any misalignments. The space 51 is filled with lubrication oil through the opening 35, which is closed by the screw 34. As already described above, the housing 30 is also provided with a threaded opening 36 for receiving the screw 38 (see FIG. 1B).
The plate 50 is coaxially provided with an opening covered with a sealing ring 53 provided with a central coaxial opening 54 for allowing access to a central, coaxial through-hole 56 through the anvil 18 along the axis A-A, i.e., the drum 19 and the two axles 42. The purpose of the through-hole 56 is to allow lifting of the anvil for maintenance thereof.
The anvil 18, i.e., the anvil drum 19 or the axles 42, is furthermore provided with an integral reference portion 60 provided with a radial surface 61 and an axial annular reference surface 62 concentric with the axis A-A.
The portion 60 is furthermore arranged with axially directed threaded openings 64 for receiving a screw 66 (see FIGS. 5A-5B), respectively.
In FIG. 4C is shown at the end of the axle 42 provided with an interior chamfer 67, constituting a reference surface for allowing centering of the anvil 18.
During manufacture of the anvil, the chamfer surface 67 is made first, then the anvil surface 43, the outer axial surface 42a of the axle 42 and the reference surface 62. Hereby, all of the surfaces are coaxial with the axis A-A. The bearings 52a, 52b can now be coaxially mounted on the axle 42.
For regrinding purposes, the anvil 18 as shown in FIGS. 5A-5B, includes a cover member 68 in the form of a circular cylindrical mantle 70 and a lid 72, preferably being an integral part of the mantle 70. The cover member 68 is arranged outside and concentric with the bearing housing on each side of the anvil drum 19, such that it abuts the radial surface 61 of the reference portion 60, leaving the annular reference surface 62 accessible.
As already stated above, each axially directed threaded opening 64 is adapted to receive a screw 66 for connecting the cover member 68 to each axial side of the anvil drum 19, i.e., to cover the bearings 52a, 52b during grinding for protecting them during machining of the anvil surface 43.
The lid 72 is provided with a blind hole 76 to be utilised during grinding as a centering point of the anvil in relation to the axis of the re-grinding machine. It also serves to support the anvil during the re-grinding operation.
The centering screws 74 ensure that the blind hole 76 is aligned with the chamfer 67, i.e., that the cover member 68 is concentric with the axis A-A.
The surface 62 is thus used for centering the blind hole 76, such that it is centered in relation to the axis A-A. This is important for positioning the anvil 18 correctly in the re-grinding machine.
The cover protects the bearings 52 from the cooling liquid during machining, and thus allows the bearings to remain on the axle 42, in turn avoiding the risk for damaging the bearings during disassembly thereof, since they can remain on the axle 42, in turn saving time during the maintenance of the anvil 18.
FIG. 6 shows a variant, according to which the centering screws 74 not only centers the cover member 68, but also connect the cover member 68 to the axial ends of the anvil drums for covering the axles 42. This is performed by tightening the screws 74 towards the bearing housing 30, or by providing the bearing housing with threaded openings for the centering screws 74. In addition, or alternatively, the cover member may be made of a magnetic material.
In order to seal the second end 71b of the cover member, it is provided with a sealing ring 61.
FIG. 7 illustrates a further variant according to which a circular-cylindrical shaft 90 is pushed into the opening 56. The shaft is provided with a male thread 92 at both ends for receiving a female thread 94 in the inside of the lid 72 of each cover member 68, for connecting and centering the cover member to the axis A-A.
Alternatively, the shaft 90 is pointed in both ends, and conical openings are provided in the inside of the lid for guiding the pointed shaft, while tightening screws 66 according to FIG. 5B.
It should be noted that the sealing member shown in FIG. 6 may be utilized in any one of the described embodiments.
The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. The scope is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced.

## Claims

1. A rotary cutting apparatus, comprising:
a cutter drum having at least one cutting member;
an anvil drum having a rotary axis and arranged in a cutting relationship to said cutter drum, wherein a bearing housing is arranged on each axial side of the anvil drum;
a pressure actuating means for subjecting pressure on said cutting member in relation to said anvil drum, said pressure actuating means arranged to cooperate with a pair of levers, said pair of levers being rotatable about a pair of hinges having a horizontal axis and connected to said pair of hinges at a respective proximal end of said levers, said horizontal axis being parallel to but non-concentric with said rotary axis, said pressure actuating means disposed adjacent to distal ends of said pair of levers and causing said levers to rotate about said hinges at their ends in an arc-shaped movement;
a frame for supporting the cutter drum and the anvil drum in a rotatable relationship, wherein said pair of levers are releasably connected to the bearing housing and rotatable about said pair of hinges in such a way that the anvil drum is allowed to be removed from the frame; and
at least one spring means arranged to act on said distal ends of the levers, said spring means positioned opposite to said actuating means for applying a counterbalancing linear force; wherein said horizontal axis of said levers is arranged vertically above said rotary axis and wherein said pressure actuating means actuates on said levers on the same side of a vertical plane through the horizontal axis as the rotary axis.

2. The rotary cutting apparatus according to claim 1, wherein said horizontal axis of said levers is arranged vertically below said rotary axis.

3. The rotary cutting apparatus according to claim 1, wherein said horizontal axis of said levers is arranged at about the same level as said rotary axis.

4. The rotary cutting apparatus according to claim 1, wherein said pressure actuating means comprises at least one pneumatic cylinder.

5. The rotary cutting apparatus according to claim 1, wherein at least one spring means is provided to counter balance the weight of the anvil.

6. The rotary cutting apparatus according to claim 1, wherein a lid is rotatably arranged at said frame, said levers being releasably connected to said lid.

7. The rotary cutting apparatus according to claim 1, wherein said pair of levers are arranged on a radial exterior side of said bearing housing, respectively.

8. The rotary cutting apparatus according to claim 7, wherein the levers are connected to the bearing housing, respectively, by means of at least one axial screw, nut or bolt.

9. The rotary cutting apparatus according to claim 2, wherein said pressure actuating means comprises at least one pneumatic cylinder and at least one spring means arranged to act on the levers at a position to the opposite to the hinge means, for allowing a predetermined force to be applied by the cylinder.

10. The rotary cutting apparatus according to claim 2, wherein said pressure actuating means actuates on said levers on the same side of a vertical plane through the horizontal axis as the rotary axis.

11. The rotary cutting apparatus according to claim 2, wherein at least one spring means is provided to counter balance the weight of the anvil.

12. The rotary cutting apparatus according to claim 2, wherein said pair of levers are arranged on a radial exterior side of said bearing housing, respectively.

13. The rotary cutting apparatus according to claim 12, wherein the levers are connected to the bearing housing, respectively, by means of at least one axial screw, nut or bolt.

14. The rotary cutting apparatus according to claim 3, wherein said pressure actuating means comprises at least one pneumatic cylinder and at least one spring means arranged to act on the levers at a position to the opposite to the hinge means, for allowing a predetermined force to be applied by the cylinder.

15. The rotary cutting apparatus according to claim 3, wherein said pressure actuating means actuates on said levers on the same side of a vertical plane through the horizontal axis as the rotary axis.

16. The rotary cutting apparatus according to claim 3, wherein at least one spring means is provided to counter balance the weight of the anvil.

17. The rotary cutting apparatus according to claim 3, wherein said pair of levers are arranged on one axial side only of said bearing housing.

18. The rotary cutting apparatus according to claim 17, wherein the levers are connected to the bearing housing, respectively, by means of at least one radial screw, nut or bolt.