KNIFE

Abstract

A knife is provided for a cutting device for cutting continuous rods in a manufacturing process, the knife including: a knife body having a distal end and a proximal end opposite the distal end, the knife body configured to be attached to a cutting device; and a cutting edge located at the distal end of the knife body, the cutting edge including at least two cutting edge segments, each cutting edge segment including a profile, the profile including one maximum protrusion from the knife body, and at least a portion of a second cutting edge segment of the at least two cutting edge segments protruding, from the knife body, to a greater extent than the maximum protrusion of a first cutting edge segment of the at least two cutting edge segments, from the knife body. A cutting device, and a method of manufacturing a cutting device, are also provided.

Claims

1.-15. (canceled)

16. A knife for a cutting device for cutting continuous rods in a manufacturing process, the knife comprising: a knife body having a distal end and a proximal end opposite the distal end, the knife body being configured to be attached to a cutting device; and a cutting edge located at the distal end of the knife body, the cutting edge comprising at least two cutting edge segments, each cutting edge segment comprising a profile, wherein the profile comprises one maximum protrusion from the knife body, and wherein at least a portion of a second cutting edge segment of the at least two cutting edge segments protrudes, from the knife body, to a greater extent than the maximum protrusion of a first cutting edge segment of the at least two cutting edge segments, from the knife body.

17. The knife according to claim 16, wherein the cutting edge further comprises a third cutting edge segment, comprising a profile, wherein the profile of the third cutting edge segment comprises one maximum protrusion from the knife body, and wherein at least a portion of the third cutting edge segment protrudes, from the knife body, to a greater extent than the maximum protrusion of the second cutting edge segment, from the knife body.

18. The knife according to claim 16, wherein the profile of at least one cutting edge segment of the at least two cutting edge segments comprises a non-linear profile.

19. The knife according to claim 16, wherein the first cutting edge segment comprises a convex curved profile.

20. The knife according to claim 16, wherein the second cutting edge segment comprises a convex curved profile.

21. The knife according to claim 17, wherein the third cutting edge segment comprises a convex curved profile.

22. The knife according to claim 16, wherein a circumference length of the second cutting edge segment is greater than a circumference length of the first cutting edge segment.

23. The knife according to claim 16, wherein a circumference length of the second cutting edge segment is less than a circumference length of the first segment.

24. The knife according to claim 16, wherein a circumference length of the second cutting edge segment is the same as a circumference length of the first cutting edge segment.

25. The knife according to claim 17, wherein a circumference length of the third cutting edge segment is greater than a circumference length of the second cutting edge segment.

26. The knife according to claim 17, wherein a circumference length of the third cutting edge segment is less than a circumference length of the second cutting edge segment.

27. The knife according to claim 17, wherein a circumference length of the third cutting edge segment is the same as a circumference length of the second cutting edge segment.

28. A cutting device for cutting a continuous rod product in a manufacturing process, the cutting device comprising: a knife holder configured to mount at least one knife, the knife holder having an actuator configured to drive a cutting edge of the at least one knife towards a product to be cut; and a knife comprising: a knife body having a distal end and a proximal end opposite the distal end, the knife body being configured to be attached to a knife holder, and a cutting edge located at the distal end of the knife body, the cutting edge comprising at least two cutting edge segments, each cutting edge segment comprising a profile, wherein the profile comprises one maximum protrusion from the knife body, and wherein at least a portion of a second cutting edge segment of the at least two cutting edge segments protrudes, from the knife body, to a greater extent than the maximum protrusion of a first cutting edge segment of the at least two cutting edge segments, from the knife body.

29. A method of operating a cutting device for cutting a continuous rod product in a manufacture process, the method comprising the steps of: providing a knife, wherein the knife comprises: a knife body having a distal end and a proximal end opposite the distal end, the knife body being configured to be attached to a knife holder, and a cutting edge located at the distal end of the knife body, the cutting edge comprising at least two cutting edge segments, each cutting edge segment comprising a profile, wherein the profile comprises one maximum protrusion from the knife body, and wherein at least a portion of a second cutting edge segment of the at least two cutting edge segments protrudes, from the knife body, to a greater extent than the maximum protrusion of a first cutting edge segment of the at least two cutting edge segments, from the knife body; mounting the knife to a knife holder, the knife holder comprising an actuator; and operating the actuator to drive a cutting surface of the knife towards a product to be cut.

30. A method of manufacturing a cutting device for cutting a continuous rod product in a manufacturing process, the method comprising the steps of: providing a knife, wherein the knife comprises: a knife body having a distal end and a proximal end opposite the distal end, the knife body being configured to be attached to a knife holder, and a cutting edge located at the distal end of the knife body, the cutting edge comprising at least two cutting edge segments, each cutting edge segment comprising a profile, wherein the profile comprises one maximum protrusion from the knife body, and wherein at least a portion of a second cutting edge segment of the at least two cutting edge segments protrudes, from the knife body, to a greater extent than the maximum protrusion of a first cutting edge segment of the at least two cutting edge segments, from the knife body; mounting the knife to a knife holder; and connecting an actuator to the knife holder such that the actuator is configured to rotate the knife holder to drive a cutting edge of the knife towards a product to be cut.

Description

[0094] Examples will be further described with reference to the figures in which:

[0095] FIG. 1 is a cutting device of the prior art;

[0096] FIG. 2 is a cutting device of the prior art;

[0097] FIG. 3 is a schematic illustration of a cutting device according to embodiment of the present invention;

[0098] FIG. 4 is a schematic illustration of a knife according to an embodiment of the present invention;

[0099] FIG. 5 is a schematic illustration of a knife according to another embodiment of the present invention;

[0100] FIG. 6 is a schematic illustration of a knife according to a further embodiment of the present invention; and

[0101] FIG. 7 is a schematic illustration of a knife according to another embodiment of the present invention.

[0102] FIG. 1 and FIG. 2 show an example of a cutting device 10 of the prior art. The cutting device 10 has a generally flat rectangular knife 1, connected at its center 3 to a shaft that rotates about a rotational axis 3. A continuous rod 4 is moved along a conveyor in a direction denoted by the arrow 7. The end of the knife 1 has a sharp cutting edge 2 which crosses the path of the continuous rod 4 to be cut as the knife 1 is rotated by the shaft, which cuts the continuous rod 4 is cut into smaller parts 5. Referring to FIG. 2, the cutting edge 2 of the knife 1 moves in a circular path 6, in a direction denoted by the arrow 12. The continuous rod 4 is placed in the path 6 of the knife 1, and is cut.

[0103] In FIGS. 3 and 4, there is shown a knife 101 and a cutting device 110 that includes the knife 101 mounted to a knife holder. In this example, the knife 101 is mounted by its center 103. The knife holder is provided with an actuator (not shown) that is used to drive and rotate the knife about its center 103, in a direction denoted by the arrow 112. The knife 101 includes a knife body having a distal end and a proximal end opposite the distal end. The knife 101 has a first lateral side 108 and a second lateral side 109 provided on a side opposite the first lateral side 108. A cutting edge generally denoted 102 is located on the distal end of the knife 101. The cutting edge 102 forms the blade of the knife 101, used to cut a continuous rod product. In this particular example illustrated, when the knife 101 is rotated about its center 103 by the actuator, the cutting edge 102 of the knife 101 moves in a circular path, denoted 106. In other examples, the cutting edge 102 of the knife 101 may move in a path that is not circular. For example, the path 106 may be elliptical. A continuous rod 104 is aligned on the cutting path 106 of the knife 101 in order to be cut by the cutting edge 102 of the knife 101 during use. The continuous rod 104 in this example is a tobacco rod having a homogenised web of tobacco, with a metal susceptor 150 embedded within the tobacco. However, other rods 104 are also envisaged such as a polylactic acid filter tow, a mouthpiece filter or a hollow acetate tube, for example.

[0104] When the cutting device 110 is driven, the cutting edge 102 of the knife 101, in this example, is driven to move in a circular path 106. The cutting edge 102 is aligned with the rod 104 to be cut, which in this case is a tobacco rod 104. At the same time, the rod 104 is moved along a conveying path. By synchronising the rotation of the knife 101 with the speed at which the rod 104 moves, the rod 104 is cut by the knife 101 to a predetermined length. In this example, the rod 104 is conveyed at a speed of 300 meters per minute, and is cut to a component length of 80 millimeters. The precision of cutting of the rod 104 is of particular importance when the cutting device 101 operates at high speeds, which is achieved by the design of the knife 101, as will now be described.

[0105] The cutting edge 102 of the knife 101 is provided with a first cutting edge segment 121, a second cutting edge segment 122, and a third cutting edge segment 123. The cutting edge segments 121,122,123 are spaced along the cutting edge 102. The first cutting edge segment 121 is located on the first lateral side 108 of the knife 101. The third cutting edge segment 123 is located on the second lateral side 122 of the knife 101 The second cutting edge segment 122 is located between the first cutting edge segment 121 and the third cutting edge segment 123. Though in this example, three cutting edge segments 121,122,123 are shown, it is envisaged that the cutting edge 102 may be provided with two cutting edge segments or more than three cutting edge segments such as for example, four, five, or six cutting edge segments. Each of the cutting edge segments 121, 122, 123 has a profile. The profile of each cutting edge segment 121,122,123 is a non-linear profile. In this example, the profile is a convex curved profile. Other profiles are also envisaged, such as a stepped profile, an asymmetric profile, an asymmetric curved profile, or a profile having a non-constant curvature.

[0106] Each cutting edge segment 121, 122, 123 is provided with a maximum protrusion from the knife body. That is, each cutting edge segment 121, 122, 123 has a point (that is, at least a portion) at which the profile protrudes a maximum distance from the body of the knife 101. The first cutting edge segment 121 has a maximum protrusion, from the knife body. The second cutting edge segment 122 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the first cutting edge segment 121. The third cutting edge segment 123 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the second cutting edge segment 122. More specifically, in this example, the maximum protrusion of the first cutting edge segment 121, from the knife body, is 20 mm. The maximum protrusion of the second cutting edge segment 122, from the knife body, is 30 mm. The maximum protrusion of the third cutting edge segment 123, from the knife body, is 40 mm. The displacement between the central pivot 103 and the maximum protrusion point of the first cutting edge segment 121 is 120 mm. The displacement between the central pivot 103 and the maximum protrusion point of the second cutting edge segment 122 is 130 mm. The displacement between the central pivot 103 and the maximum protrusion point of the third cutting edge segment 123 is 140 mm.

[0107] The profile of each cutting edge segment 121, 122, 123 has a different circumference length in this example. The circumference length describes a length measurement of the curved profile. The circumference length describes the curvature of the cutting edge segment profile, about the respective center. In some example embodiments, the circumference length may refer to the length of the curved profile along its profile. The circumference length of the first cutting edge segment 121 is 30 millimetres, about the center 131, in this example, but it is envisaged that the circumference length may be in the range of 16 millimetres and 50 millimetres. The second cutting edge segment 122 has a circumference length that is greater than the circumference length of the first cutting edge segment 121. The circumference length of the second cutting edge segment 122 is 70 millimetres, about the center 132, in this example, but it is envisaged that the circumference length may be in the range of 50 millimetres and 100 millimetres. The third cutting edge segment 123 has a circumference length that is greater than the circumference length of the second cutting edge segment 122. The circumference length of the third cutting edge segment 123 is 130 millimetres, about the center 133, in this example, but it is envisaged that the circumference length may be in the range of 100 millimetres and 200 millimetres. When the knife 101 is in use, the cutting edge 102 which includes the first cutting edge segment 121, the second cutting edge segment 122, and the third cutting edge segment 123 contacts the product or article to be cut. In this example, the product to be cut is a continuous rod.

[0108] During cutting, the first cutting edge segment 121 of the cutting edge 102 comes into contact with the rod 104 to make an initial incision into the rod 104. As shown in FIG. 3, the first cutting edge segment 121 has a minimum protrusion point which moves in the path denoted 152, and a maximum protrusion point which moves in the path denoted 154. In this example embodiment, as the cutting edge 102 comes into contact with the rod 104, the minimum protrusion point on the first cutting edge segment 121 does not contact the rod 104. The maximum protrusion point of the first cutting edge segment 121 comes into contact with the rod 104. It can be seen that the first cutting edge segment 121 in this example is able to cut the rod 104, but not the susceptor 150 within the rod 104. As the knife 101 is moved further towards the rod 104, the second cutting edge segment 122 comes into contact with the rod 104 to further cut the rod 104. As the rod 104 comes into contact with and along the cutting edge 102 of the knife 101, the rod 104 is cut progressively. It can be seen that since the second cutting edge segment 122 protrudes to a greater extent that the first cutting edge segment 121, the second cutting edge segment 122 is capable of cutting the susceptor 150. In this particular embodiment, since the susceptor 150 is made from a relatively hard material in comparison to the tobacco, the susceptor 150 is displaced within the tobacco. As the knife 101 is moved further towards the rod 104, the third cutting edge segment 123 comes into contact with the rod 104, to cut it. The circumference length of the cutting edge segments 121, 122, 123 increase in the direction opposite the moving direction of the knife. The part of the cutting edge 102 with the smallest circumference length (the first cutting edge segment 121) is the first to contact the rod to be cut, followed by the subsequent (that is, second and then third) cutting edge segments 122, 123. The progressive cutting of the rod 104 in this way reduces wear of the cutting edge 102 of the knife 101. Also, cutting the rod 104 progressively like this requires less force to cut the rod 104 and the rod 104 has a greater chance of being cut by at least one of the cutting edge segments 121, 122, 123.

[0109] In some examples, the cutting edge 102 of the knife 101, or any surface of the knife 101 that is subject to wear, may be coated in a harder material to further reduce wear. For example, the cutting edge 102 may be coated in a ceramic material. In other examples, the knife 101 may be coated in a metal carbide or a metal nitride coating, for example. In some examples, the profile of the cutting edge segments 121, 122, 123 have a non-linear profile such as an asymmetric profile, an asymmetric curved profile, or a profile with a non-constant curve, for example. In one example, the profile of the cutting edge segments 121, 122, 123 has a stepped profile. The provision of a stepped profile provides a sharp change in the displacement between the contact point for the rod, and the central pivot of the knife 101, leading to a smooth cut.

[0110] FIG. 5 shows another example of a knife 101 having substantially the same features as the knife of FIG. 4, having a cutting edge 102 with a different design. The cutting edge 102 of the knife 101 is provided with a first cutting edge segment 121, a second cutting edge segment 122, and a third cutting edge segment 123. The cutting edge segments 121, 122, 123 have a convex curved profile. The first cutting edge segment 121 has a maximum protrusion, from the knife body. The second cutting edge segment 122 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the first cutting edge segment 121. The third cutting edge segment 123 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the second cutting edge segment 122.

[0111] In this example, the circumference length of the first cutting edge segment 121 is 150 mm, about the center 131, but it is envisaged that the circumference length may be in the range of 100 millimetres and 200 millimetres. The second cutting edge segment 122 has a circumference length that is greater than the circumference length of the first cutting edge segment 121. The circumference length of the second cutting edge segment 122 is 80 millimetres, about the center 132, in this example, but it is envisaged that the circumference length may be in the range of 50 millimetres and 100 millimetres. The third cutting edge segment 123 has a circumference length that is greater than the circumference length of the second cutting edge segment 122. The circumference length of the third cutting edge segment 123 is 25 millimetres, about the center 133, in this example, but it is envisaged that the circumference length may be in the range of 16 millimetres and 50 millimetres.

[0112] During cutting, the first cutting edge segment 121 of the cutting edge 102 comes into contact with the rod first to cut the rod. As the knife 101 is moved further towards the rod 104, the second cutting edge segment 122 comes into contact with the rod 104 to further cut the rod 104. As the knife 101 is moved further towards the rod 104, the third cutting edge segment 123 comes into contact with the rod 104, to cut it. The circumference length of the cutting edge segments 121, 122, 123 decrease in the direction opposite the moving direction of the knife. The part of the cutting edge 102 with the largest circumference length (the first cutting edge segment 121) is the first to contact the rod to be cut, followed by the subsequent (that is, second and then third) cutting edge segments 122, 123. This arrangement is particularly beneficial where the product to be cut is made of a flexible material. After the first cutting edge segment 121 contacts the rod, the rod may deform. As such, it is beneficial for the second cutting edge segment 122 (subsequent cutting edge segments) to have a circumference length that is smaller than the preceding segment(s), allowing the rod to contact the cutting edge further away.

[0113] FIG. 6 shows another example of a knife 101. The knife has substantially the same features as the aforementioned knives. However, the cutting edge is provided with a first cutting edge segment 121 having a circumference length that is greater than the circumference length of the second cutting edge segment 122, but less than the circumference length of the third cutting edge segment 123. In this example, the circumference length of the first cutting edge segment 121 is 90 millimetres, about the center 131, but it is envisaged that the circumference length may be in the range of 50 millimetres and 100 millimetres. The circumference length of the second cutting edge segment 122 is 35 millimetres, about the center 132, but it is envisaged that the circumference length may be in the range of 16 millimetres to 50 millimetres. The circumference length of the third cutting edge segment 123 is 110 millimetres, about the center 133, but it is envisaged that the circumference length may be in the range of 100 millimetres and 200 millimetres. During cutting, the first cutting edge segment 121 of the cutting edge 102 comes into contact with the rod first to cut the rod. As the knife 101 is moved further towards the rod 104, the second cutting edge segment 122 comes into contact with the rod 104 to further cut the rod 104. As the knife 101 is moved further towards the rod 104, the third cutting edge segment 123 comes into contact with the rod 104, to cut it.

[0114] FIG. 7 shows another example of a knife 101. The knife 101 is substantially the same as the knife in FIG. 4, but the cutting edge 102 of the knife 101 is provided with four cutting edge segments. The cutting edge 102 of the knife 101 is provided with a first cutting edge segment 121, a second cutting edge segment 122, a third cutting edge segment 123, and a fourth cutting edge segment 124, spaced along the cutting edge 102. The first cutting edge segment 121 is located on the first lateral side 108 of the knife 101. The fourth cutting edge segment 124 is located on the second lateral side 109 of the knife 101 The second cutting edge segment 122 and the third cutting edge segment 123 are located between the first cutting edge segment 121 and the fourth cutting edge segment 124. The profile of each cutting edge segment 121, 122, 123, 124 is a non-linear profile. In this example, the profile is a convex curved profile.

[0115] Each cutting edge segment 121, 122, 123, 124 is provided with a maximum protrusion from the knife body. The first cutting edge segment 121 has a maximum protrusion, from the knife body. The second cutting edge segment 122 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the first cutting edge segment 121. The third cutting edge segment 123 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the second cutting edge segment 122. The fourth cutting edge segment 124 has a maximum protrusion, from the knife body, that is greater than the maximum protrusion of the third cutting edge segment 123.

[0116] The profile of each cutting edge segment 121, 122, 123, 124 has a different circumference length. The circumference length of the first cutting edge segment 121 is 25 millimetres, about the center 131, in this example, but it is envisaged that the circumference length may be in the range of 10 millimetres and 40 millimetres. The second cutting edge segment 122 has a circumference length that is greater than the circumference length of the first cutting edge segment 121. The circumference length of the second cutting edge segment 122 is 60 millimetres, about the center 132, in this example, but it is envisaged that the circumference length may be in the range of 40 millimetres and 80 millimetres. The third cutting edge segment 123 has a circumference length that is greater than the circumference length of the second cutting edge segment 122. The circumference length of the third cutting edge segment 123 is 100 millimetres, about the center 133, in this example, but it is envisaged that the circumference length may be in the range of 80 millimetres and 120 millimetres. The circumference length of the fourth cutting edge segment 124 is 140 millimetres, about the center 134, in this example, but it is envisaged that the circumference length may be in the range of 120 millimetres to 160 millimetres.

[0117] When the first cutting edge segment 121 of the cutting edge 102 comes into contact with the rod to be cut, an incision is made onto the rod. As the knife 101 is moved further towards the rod 104, the second cutting edge segment 122 comes into contact with the rod 104 to further cut the rod 104. As the rod 104 comes into contact with and along the cutting edge 102 of the knife 101, the rod 104 is cut progressively. As the knife 101 is moved further towards the rod 104, the third cutting edge segment 123 comes into contact with the rod 104, to cut it. When the knife 101 is moved still further towards the rod 104, the fourth cutting edge segment 124 comes into contact with the rod 104, to cut it. The circumference length of the cutting edge segments 121, 122, 123, 124 increase in the direction opposite the moving direction of the knife. The part of the cutting edge 102 with the smallest circumference length (the first cutting edge segment 121) is the first to contact the rod to be cut, followed by the subsequent (that is, second and then third and then fourth) cutting edge segments 122, 123, 124. The progressive cutting of the rod 104 in this way reduces wear of the cutting edge 102 of the knife 101.

[0118] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term “about”. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A plus or minus 5 percent of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentage enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention.

[0119] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein.

[0120] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise.

[0121] As used in this specification and the appended claims, the term “or” is generally employed in its sense including, alternatively or in addition, unless the content clearly dictates otherwise.

[0122] As used herein, “have”, “having”, “include”, “including”, “comprise”, “comprising” or the like are used in their open-ended sense, and generally mean “including, but not limited to”. It will be understood that “consisting essentially of”, “consisting of”, and the like are subsumed in “comprising,” and the like.

[0123] The words “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and, is not intended to exclude other embodiments from the scope of the disclosure, including the claims.

[0124] Any direction referred to herein, such as “top,” “bottom,” “left,” “right,” “upper,” “lower,” and other directions or orientations, including numbering like first, second and third, are described herein for clarity and brevity are not intended to be limiting of an actual device or system. Devices and systems described herein may be used in a number of directions and orientations.

[0125] The embodiments exemplified above are not limiting. Other embodiments consistent with the embodiments described above will be apparent to those skilled in the art.