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Title:
BLADE FOR CUTTING TOBACCO FIBRES OF PREDETERMINED LENGTH AND METHOD FOR MANUFACTURING IT
Document Type and Number:
WIPO Patent Application WO/2012/064209
Kind Code:
A1
Abstract:
A method of preparing a slidable blade mounted on a drum of a tobacco cutter for cutting the fibres of a predetermined length in which the cutting edge of the blade is being bevelled by moving a grinding wheel along the generatrix of the drum, wherein on the bevelled part (7, 7') of the blade (1, 1') grooves (6, 6') are formed by means of a set of stationary grinding wheels (4, 4'), the grooves being substantially perpendicular to the cutting edge of the blade. The blade prepared according to this method comprising the grooves (6, 6') on the bevelled surface (7, 7') arranged substantially in parallel to one another with a triangular or rectangular cross section.

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Inventors:
DRUZDZEL ARKADIUSZ (PL)
Application Number:
PCT/PL2011/050046
Publication Date:
May 18, 2012
Filing Date:
November 10, 2011
Export Citation:
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Assignee:
INT TOBACCO MACHINERY POLAND (PL)
DRUZDZEL ARKADIUSZ (PL)
International Classes:
B26D1/00; A23F3/12; A24B7/04; A24B7/12; B24B19/02
Domestic Patent References:
WO2004080215A12004-09-23
WO1985004616A11985-10-24
WO1995007031A11995-03-16
WO2010029348A22010-03-18
Foreign References:
US6595216B12003-07-22
DE20301912U12003-05-22
DE102009046666A12011-05-19
Attorney, Agent or Firm:
KARCZ, Katarzyna (Nowoursynowska 162J Ursynów, Warszawa, PL)
Download PDF:
Claims:
Patent claims

1. A method for preparing a slidable blade mounted on a drum of a tobacco cutter for cutting the fibres of a predetermined length in which the cutting edge of the blade is bevelled by moving a grinding wheel along the generatrix of the drum, characterized in that on the bevelled part (7, 7') of the blade (1, 1') grooves (6, 6') are formed by means of a set of stationary grinding wheels (4, 4'), the grooves (6, 6') being substantially perpendicular to the cutting edge of the blade.

2. The method according to claim 1, characterized in that the grooves (6) of a triangular cross section are formed by means of stationary grinding wheels (4) .

3. The method according to claim 1, characterized in that the grooves (6') of a rectangular cross section are formed by means of stationary grinding wheels (4') .

4. The method according to claim 2 or 3, characterized in that the ratio of the width w of the grooves to the width s_ of the fibres being cut off is at most 5 to 1.

5. The method according to claim 4, characterized in that the ratio of the width w of the grooves to the width s_ of the fibres being cut off is at most 1 to 1.

6. The method according to claim 1, characterized in that stationary grinding wheels (4, 4') for forming the grooves (6, 6') are used, the stationary grinding wheels (4, 4') being arranged on a shaft (5) parallel to the drum axis (2) .

7. The method according to claim 4, characterized in that the grinding wheels (4, 4') for forming the grooves (6, 6') arranged at equal distances along the shaft (5) are used.

8. A blade mounted on a drum of a tobacco cutter, in the form of a flat plate bevelled on the rim forming its cutting edge, prepared according to the method defined in claim 1, characterized in that it comprises the grooves (6), (6') on the bevelled surface (7, 7') arranged substantially in parallel to one another.

9. The blade according to claim 6, characterized in that the grooves (6) have a triangular cross section.

10. The blade according to claim 6, characterized in that the grooves (6) have a rectangular cross section.

Description:
Method of preparing a slidable blade mounted on a drum of a tobacco cutter for cutting fibres of a predetermined length and a blade prepared according to this method The invention relates to a method of preparing a slidable blade mounted on a drum of a tobacco cutter for cutting fibres of a predetermined length and a blade prepared according to this method.

The tobacco cutters equipped with cutting drums with at least two blades are commonly used in the tobacco industry. Most commonly used are the blades having a linear cutting edge. The blades having many collinear cutting edges shaped in such a way as to cut off the tobacco fibres of a predetermined length are also known.

The document WO85/004616 refers to cutting tobacco fibres of a predetermined length and presents a design of a flat blade bevelled on one side comprising grooves made on the side opposite to the bevelled surface. Small protuberances located between each two adjacent grooves cut off the fibres to a certain length, i.e. the groove width determines the maximum length of the fibres being cut off.

The document WO95/007031 presents a cutter drum equipped with knives of various thickness and various angular positions. The drum is equipped with at least one knife comprising protuberances situated as in the previous document, on the side opposite to the blade bevelling, the protuberances having a triangular cross section and both ends of the blade being formed as gripping parts which are flat on both sides. In both above documents, the fibre length is determined by the spacing of the small protuberances formed on the side opposite to bevelled surface of the blade.

The document W02010 /029348 discloses a method for preparing a flat blade for cutting off the fibres widthwise the shape of which that is required for cutting is conferred during the operation of the cutter by means of a grinding wheel. The preparation of the blade consists in forming grooves by grinding the originally rectilinear edge of the blade, a single grinding wheel being used to sharpen all the cutting edges of both the teeth and the grooves of the blade. According to this disclosure the fibres are cut off widthwise by means of both the cutting edge of the grooves and the cutting edge of the teeth. The side cutting edges of the teeth cut off the fibres lengthwise, the width of the grooves being equal to the width of the teeth.

The object of the present invention is to provide a simple method of preparing a blade mounted on a cutter drum for cutting tobacco fibres of a predetermined length in which narrow grooves are formed on the bevelled side of the cutting edge of the blade and all the cutting edges of the blade that cut fibres widthwise are collinear.

According to the invention, a method is provided of preparing a blade mounted on a cutter drum for cutting the tobacco fibres of a predetermined length, in which on the bevelled part of each blade grooves are formed by means of a set of stationary grinding wheels, the grooves being substantially perpendicular to the cutting edge of the blade.

Preferably, grooves having a triangular cross section are formed by means of a set of stationary grinding wheels. Optionally, grooves having a rectangular cross section are formed .

Preferably, the ratio of the groove width to the width of the fibres being cut off does not exceed the 5 to 1 ratio.

The best effect is obtained when the ratio of the groove width to the width of the fibres being cut off does not exceed the 1:1 ratio.

Stationary grinding wheels arranged on an axis parallel to the axis of the drum are used for forming the grooves.

Preferably, grinding wheels arranged at equal distances along the axis are used.

According to another aspect of the invention, a blade is provided for mounting on a drum of a tobacco cutter, the blade having the form of a flat plate bevelled on the rim forming its cutting edge. The blade of the invention is prepared according to the method according to the invention and it comprises grooves on the bevelled surface arranged substantially in parallel to one another.

Preferably, the grooves have a triangular cross section or a rectangular cross section.

The method of the invention is a simple design solution in which a set of stationary grinding wheels is used. Forming of a narrow groove in the bevelled part of the blade provides for the proper cutting of the fibres lengthwise. The method provides a way to easily change the shape of the groove which is being formed, the change of the depth of the grooves being possible during the operation of the cutter.

The object of the invention is presented by way of non- limiting example in the drawing, in which: Fig. shows, in a simplified form, a cutter head with the grinding wheels for sharpening the edges of the blades; Fig. 2 shows a set of the grinding wheels for forming the V-shaped grooves; Fig. 3 shows a set of the grinding wheels for forming the grooves of a rectangular cross section; Fig. 4 shows a perspective view of a blade with the grooves of a triangular cross section; Fig. 5 shows a perspective view of a blade with the grooves of a rectangular cross section.

The blades 1 mounted on the circumference of the drum 2 of a tobacco cutter (Fig. 1), are sharpened during the operation of the cutter in a known manner by means of grinding wheels 3 moving along the generatrix of the drum 2 of the cutter so as to sharpen the blades 1 by bevelling on their cutting edges. The cutter for the realisation of the method according to the invention is further equipped with a plurality of the grinding wheels 4 mounted on an axis 5 (Fig. 2 and 3), the grinding wheels being used for forming the grooves on the bevelled part of the blades 1. The grinding wheels 4 of Fig. 2 have their cross section surface in the form of two adjoining truncated cones. The grinding wheels 4 are designed to form the grooves 6 having a triangular cross section on the bevelled part 7 of the blade 1 shown in Fig. 4. During the operation of the cutter, the wheels 4 wear out and need to be sharpened by means of a tool mapping the shape of the grooves 6. The distance between the axis of rotation of the wheel and the axis of rotation of the cutter drum must be simultaneously adjusted in a known manner. The known mechanisms for sharpening and adjusting the position of the wheels are not shown in the figures. The grinding wheels 4' of Fig. 3 have a cylindrical working surface and they are designed to form the grooves 6' of a rectangular cross section on the bevelled part 7' of the blade 1' shown in Fig. 5. During the operation of the cutter, the wheels 4' wear out and need to be sharpened by means of a tool mapping the shape of the grooves 6' . The distance between the axis of rotation of the wheel and the axis of rotation of the cutter drum must be simultaneously adjusted in a known manner. The known mechanisms for sharpening and adjusting the position of the wheels are not shown in the figures. The number and the length of the sections of the cutting edges 8 and 8' of the blades 1 and 1', situated between the grooves 6 and 6' cutting the adjoining fibres apart, will be determined by the arrangement of the grinding wheels. Typically, the distances between the consecutive grinding wheels are equal and consequently the equal lengths of the sections of the cutting edges 8 and 8' define the maximum length of the fibres being cut off. The proper cutting of the fibres is obtained by ensuring an adequate ratio of the width w of the grooves 6, 6' (Fig. 4 and 5) to the width s of the fibres (Fig. 1) being cut off. The width w of the grooves 6, 6' may be at most the quintuple of the width s of the fibres being cut off. The most preferable parameters of the cutting are obtained when the width w does not exceed the width s.