Cutting tobacco material

Abstract

 Methods and machines effective for cutting tobacco or tobacco rod incorporate a cutting blade, a cutting edge of which is of ceramic material. The ceramic material has a superior resistance to wear in comparison with the cutting edge of a conventional steel blade and thus the requirement for blade feed means and blade sharpening means is obviated.

Description

[0001] The subject invention relates to the cutting of tobacco in tobacco cutting machines and to the cutting of tobacco rod on cigarette making machines.

[0002] Conventional for cutting lamina tobacco or stem tobacco in the preparation of cigarette filler are tobacco cutting machines tobacco feed means of which comprise upper and lower conveyors, which conveyors are convergent in the direction of tobacco feed. Because of the convergency of the feed conveyors, tobacco fed between them is progressively compressed to form a so-called cheese. At exit from the feed means constituted by the upper and lower conveyors the cheese passes into a passageway in a rigid throat block. Disposed to the downstream side of the throat block, i.e. to that side remote the feed means, is cutting means generally comprising a rotatively drivable cylinder, disposed horizontally and perpendicularly to the direction of feed of the tobacco, and a number of steel cutting blades, four for example, mounted on the cylinder. In operation of such tobacco cutting machine, as the compressed tobacco cheese is advanced through the passage in the throat block towards the downstream, outlet of the passage in the block, the cylinder is rotated, in synchronism with the feed of the cheese, whereby the cutting edges of the cutting blades pass across, and in close proximity to, the said outlet and, in doing so, effect a cutting of the cheese at the forward face thereof.

[0003] Such a tobacco cutting machine is described in US 3,117,602.

[0004] As is disclosed in US 3,117,602, during each rotation of a cutting blade, the blade passes into contact with a grinding tool, there thereby being effected a sharpening action on the cutting edge of the blade. In that such continually repeated sharpening actions serve to remove metal from the outer, cutting edges of the blades, provision is made for the blades to be continuously fed outwardly of the cylinder during operation of the cutting machine. As is exemplified in US 3,117,602 the structure and mechanism requisite to effect such feed of the cutting blades is complex, and thus a cylinder so provided is costly. It is an object of the subject invention to obviate the necessity for such complexities and contingent costs of the cylinder.

[0005] The subject invention provides tobacco cutting apparatus comprising tobacco feed means and tobacco cutting means, the feed means being operable to feed a compressed body of tobacco towards the cutting means and the cutting means comprising a cutting blade a cutting edge of which is of ceramic material.

[0006] In that the ceramic material has, compared with the steel of the conventional blades, a far superior resistance to the wear that is engendered by contact with the forward face of the cheese, the ceramic cutting edges remain effectively sharp over a prolonged period, after which period the blades are removed and replaced with fresh blades. Thus there is no requirement for the provision of blade feed means or for on-machine blade sharpening means. The blade with ceramic cutting edges can be fixedly secured to the cylinder so that during operation of the cutting machine the cutting edges of the blades remain at a fixed location relative to the cylinder.

[0007] Suitably, the ceramic material is or includes aluminium oxide. The process of forming the ceramic material may include high pressure compaction of particles and thermal hardening.

[0008] The subject invention also provides a method of cutting tobacco, wherein a compressed body of tobacco is fed towards rotary cutting means comprising a cutting blade, a cutting edge of said blade being of ceramic material and said blade being maintained during the cutting operation at a fixed location relative to the axis of rotation of said cutting means.

[0009] The subject invention further provides a tobacco cutting machine cutting cylinder, said cylinder comprising non-feed fixing means whereby a plurality of cutting blades can be fixedly secured of said cylinder at respective locations equiangularly spaced about said cylinder. "Non-feed" is to be taken to have reference to the blades remaining in a fixed location relative to the cylinder during the cutting operation.

[0010] In order that the subject invention may be clearly understood and readily carried into effect reference will now be made to the diagrammatic drawings herewith, in which:-

Figure 1 shows a partial cross-sectional view of a cutting cylinder of a tobacco cutting machine; and

Figure 2 shows a cutting blade.

[0011] The steel cutting cylinder, designated by reference numeral 1, is mounted horizontally in a tobacco cutting machine in operative relationship to a throat block 2 of the machine. The cylinder 1 is rotatively drivable in the direction of arrow A by drive means (not shown).

[0012] The cylinder is relieved for the purpose of receiving an elongate ceramic cutting blade 3 and to receive a clamping plate, which plate is held in the clamping condition thereof, by a number of bolts, one of which is shown in Figure 1 and is designated by reference numeral 5. By means of the clamping plate 4 the blade 3 is held fixedly relative of the cylinder 1. In that the inner edge of the blade 3 abuts a relief edge 6 of the cylinder 1, the blade 3 is accurately located relative to the cylinder 1. The blade 3 is manufactured so that the width dimension thereof lies within precision tolerances. It is thus assured that by abutting the blade 3 against the relief edge 6 the cutting edge 7 of the blade 3 is accurately positioned relative to outlet face 8 of the throat block 2.

[0013] Three or more other identical blades (not shown) are secured, by identical securement means, to cylinder 1, the totality of the blades being equi-angularly spaced of the cylinder. The total number of blades may be six or more.

[0014] Instead of the ceramic cutting blades being of unitary construction, each blade may be constituted by a plurality of discrete, abutting elements. Such a blade, designated by reference numeral 9, is shown in Figure 2. The blade 9 is constituted of five discrete, abutting elements 10 to 14. Thus if, for example, the cutting edge becomes damaged, the element concerned can be replaced without the necessity for the whole blade being replaced.

[0015] As an aid to accurately adjusting the location of the blade 3 relative to the cylinder 1 there may be utilised a shim, which shim is inserted between, and in contact with each of, the relief edge 6 and the inner edge of the blade 3.

[0016] Cutting blades used in accordance with the subject invention may be formed of a ceramic material which is designated 'Z900 Zirconia' by Morgan Matroc Limited, fabricators of ceramic items. The material may be a composite, fibre reinforced material, in which case the reinforcement may be by way of ceramic whiskers.

[0017] As is a matter of common general knowledge to those skilled in the tobacco art, cigarette making machines operate to produce continuously a rod comprising a smoking material filler and a paper wrapper, such rod being referred to herein as tobacco rod. To the same persons it is also a matter of common general knowledge that cigarette making machines include a cut-off unit the function of which is to sever the tobacco rod, as the rod is fed to the unit by elements of the making machine which act as feed means, thus to produce discrete sections of rod, the length of which sections is that required for cigarettes. Such cut-off unit comprises rotary mounting means on which is mounted one or more cutting blades. As the mounting means rotates the or each blade severs the tobacco rod and the or each blade is brought into contact with a grinding tool, there thereby being effected a sharpening action on the cutting edge of the or each blade. In that such continually repeated sharpening actions serve to remove metal from the outer, cutting edge of the or each blade, provision is made for the blade or blades to be continuously fed outwardly of the mounting means during operation of the cut-off unit.

[0018] The subject invention yet further provides a cigarette making machine cut-off unit comprising rotary mounting means and a cutting blade mounted of said mounting means, the said blade being secured of said mounting means by non-feed fixing means and the cutting edge of said blade being of ceramic material.

[0019] The subject invention even further provides tobacco material cutting apparatus comprising rotary mounting means and a cutting blade mounted of said mounting means, the said blade being secured of said mounting means by non-feed fixing means and the cutting edge of said blade being of ceramic material.

[0020] As used herein the term "tobacco material" includes both tobacco rod (as defined hereinabove) and tobacco as such.

[0021] In providing tobacco material cutting apparatus in accordance with the subject invention there is no need, of course, to provide in the apparatus blade sharpening means.

Claims

1. Tobacco cutting apparatus comprising tobacco feed means and tobacco cutting means, the feed means being operable to feed a compressed body of tobacco towards the cutting means and the cutting means comprising a cutting blade, the cutting edge of which is of ceramic material.

2. Apparatus according to Claim 1, wherein the ceramic material is, or includes, aluminium oxide.

3. Apparatus according to Claims 1 or 2, wherein the ceramic material is, or includes, zirconium oxide.

4. Apparatus according to any one of the preceding claims, wherein the ceramic material is a composite, fibre reinforced material.

5. Apparatus according to any one of the preceding claims, wherein the ceramic material is formed by high pressure compaction of particles followed by thermal hardening.

6. Apparatus according to any one of the preceding claims, wherein the cutting means comprises a plurality of cutting blades.

7. Apparatus according to Claim 6, wherein there are more than four cutting blades.

8. Apparatus according to any one of the preceding claims, wherein the or each cutting blade comprises a plurality of discrete, abutting elements.

9. Apparatus according to any one of the preceding claims, wherein said cutting means comprises rotary mounting means and the or each cutting blade is fixedly secured of said mounting means

10. A method of cutting tobacco, wherein a compressed body of tobacco is fed towards a rotary cutting means comprising a cutting blade, a cutting edge of said blade being of ceramic material and said blade being maintained during the cutting operation at a fixed location relative to the axis of rotation of said cutting means.

11. A tobacco cutting machine cutting cylinder comprising non-feed fixing means, whereby a plurality of cutting blades can be fixedly secured of said cylinder at respective locations equiangularly spaced about said cylinder.

12. A cutting cylinder according to Claim 11 a plurality of cutting blades being fixedly secured of said cylinder by way of said fixing means, the cutting edges of which blades are of ceramic material.

13. Cigarette making machine cut-off unit comprising rotary mounting means and a cutting blade mounted of said mounting means, the said blade being secured of said mounting means by non-feed fixing means and the cutting edge of said blade being of ceramic material

14. Tobacco material cutting apparatus comprising rotary mounting means and a cutting blade mounted of said mounting means, the said blade being secured of said mounting means by non-feed fixing means and the cutting edge of said blade being of ceramic material

Drawing