GB2139073A - Tongue for making cigarette rods - Google Patents

Abstract

A tongue for making cigarette rods having a mounting fixture 3a and a tongue body 3 for guiding shredded tobacco in a predetermined direction. The tongue body 3 is formed with a generally converging bore therewithin, the bore including a plurality of truncated sections, which have sizes gradually smaller toward the predetermined direction, each truncated section being defined by a first inner surface 3b, having a gradually smaller diameter toward the predetermined direction. Each two adjacent truncated sections define a stepped portion therebetween which has a second inner surface 3b, which faces said predetermined direction. The shredded tobacco is forced to be compressed and then relaxed along the stepped guide surface. While the combination of compression and relaxation is repeated, the diameter of the cigarette is gradually reduced to that desired. <IMAGE>

Description

SPECIFICATION Tongue for making cigarette rods Background of the invention This invention relates to a tongue for making cigarette rods. In the known cigarette rod making equipment, the shredded tobacco placed on the cigarette paper is carried on the endless garniture tape. While the shredded tobacco passes through the cigarette rod forming device called winding paper section, a piece of cigarette paper is wound around the shredded tobacco. Before in this ribbontype paper winding process, the shredded tobaco on the cigarette paper is compressed into a rod and the cigarette paper is guided in circle around the tobacco rod and wound on the shredded tobacco.

A guide for compressing the shredded tobacco into a cigarette rod is called a tongue, which is known as one of the constituents that form the cigarette rod forming section.

The tongue is a guide shaped like a truncated cone cut longitudinally in half, i.e., it forms a tunnel which has a semicircular lateral cross section with its cross-sectional area gradually reducing so that the shredded tobacco passing through the guide is compressed. Conventionally, the guiding surface of the tongue is very smooth and the tunnel inner surface is formed of inclined surface with its radius linearly reducing from the inlet to the outlet.

Running the cigarette making equipment efficiently is the greatest concern of the cigarette makers and they are making efforts to prevent the occurrence of any trouble that will lead to a halt of the equipment.

There are many possible causes of such troubles.

One of the commonest troubles occurs in the process of guiding and compressing into a cigarette rod the bulky shredded tobacco put on the cigarette paper which is restricted in the widthwise direction.

During this process, the shredded tobacco being compressed and guided through the tongue clogs it, stalling the shredding tobacco system. This kind of trouble accounts for about 1 per cent of the working time of the cigarette making equipment and about 10 per cent of the halt time. Therefore, removal of the cause of such trouble is an urgent problem.

As a measure for preventing the clogging of the tongue, it is proposed that the inner surface of the tongue be finished rough, pointing out that the long period of use results in the inner surface of the tongue being worn and smooth like a mirror surface.

The proposed measures include the sand-blast finish and other means for making the surface rough.

It is also pointed out as the possible cause of clogging that the resistance of the compression path produces speed variation of the shredded tobacco.

To avoid this problem, it has been proposed to form many projections on the tongue inner surface. This will form an airfilm which in turn reduce the contact resistance and the vibration of the air film is considered to facilitate the compressing process of the shredded tobacco.

In recent years, with the increasing use of the shredded tobacco which is specially treated to be bulky and with the operating speed of the cigarette making equipment tending to increase, the shredded tobacco to be processed becomes bulky and tar (resin) readily collects on the tongue. The tar attaching to the tongue hinders smooth running of the shredded tobacco through it to cause the clog of the tobacco.

As the temperature of the tongue reaches as high as 80 degree C due to friction of the shredded tobacco, it has been found that the formation of tar on the tongue surface grows remarkably.

To prevent the formation of tar, some means have been put into practice and proved to be effective to some extent. These include supplying of cool air into the tongue and impregnating the tongue inner surface with teflon. However, the use of cool air increases the tendency of shredded tobacco seizing on the cigarette pasting part. Also with the impregnation with teflon, there is a problem of insufficient durability of teflon.

Summary ofthe invention The present invention has been accomplished based on many test results to restrict the tongue temperature increase and at the same time prevent the clogging of tongue with tar.

It is therefore an object of the present invention to provide a cigarette rod forming tongue which can prevent increasing of the tongue temperature.

It is another object of the present invention to provide a cigarette rod forming tongue which is a truncated cone cut longitudinally in half to compress the shredded tobacco into cigarette rod. Afeature of this invention is characterised in that it has a stepped guide surface essentially consisting of a series of truncated cones with the smaller diameter end arranged in the direction of movement of the shredded tobacco.

Other objects and advantages of the present invention will become apparent from the detailed description to follow taken in conjunction with the drawings.

Brief description of the drawings Figure 1 is a front view showing the outline of the cigarette rod forming section equipped with the tongue of this invention; Figure 2 is a perspective view of the tongue of this invention; and Figure 3 is a longitudinal cross-sectional view of the above tongue.

Detailed description of the embodiments Preferred embodiment of the invention will be described in detail with reference to the drawings.

In Figure 1, reference numeral 1 denotes an endless porous band driven by the drive roller 1-1 in the direction indicated by the arrow. Provided above the porous band 1 is a suction chamber (not shown) to draw air through the porous band 1 into the suction chamber so as to hold the shredded tobacco carried by airflow onto the underside of the porous band 1. The suction chamber extends as far as under the driver roller 1-1.

The fairly long porous band 1 extends over the cigarette paper 4 which is moved horizontally to- ward the left of the drawing by the guide rollers 4-1 and 4-2 and which is supported by the endless garniture tape 5. The garniture tape 5 is moved by the rollers 5-2 and 5-3 along the garniture guide 5-1.

The porous band 1 and the cigarette paper 4 pass into the converging passage where they meet, one above the other. The cigarette paper 4 is arranged so that the paper moves at the same speed as the porous band 1.

The garniture guide 5-1 gradually changes its iateral cross section from the roller 4-2 to immediately before the end of the suction chamber so as to form the garniture tape 5 into the U-shape cross section.

Where the suction chamber terminates, the porous band 1 and the cigarette paper 4 simultaneously engage with the shredded tobacco and are sufficiently close to each other to hold the shredded tobacco between them.

At the next process of the porous band 1 over the cigarette paper 4, a shredded tobacco compressing passage consisting of a compressing shoe 2 and a tongue body 3 is mounted on this cigarette making equipment.

In the paper winding section 6 provided at a process after the tongue 3, the cigarette paper 4 is wound around the compressed tobacco rod with one end of the paper pasted to the other end. The pasting is done by the pasting section 7. Provided at a process after the paper winding section 6 are a drying section 8 and a cigarette rod cutting section (not shown) in sequence. The pasted part of the cigarette rod is dried by the drying section 8 and then cut to a required length of individual cigarettes.

Figures 2 and 3 show one example of the tongue according to this invention.

The tongue body 3 has a stepped guiding portion 3b (described later) inside a tunnel of semi-circular cross section. Its basic shape is a tunnel of semicircular cross section with its inner cross-setional area gradually reducing. Namely, the tongue body 3 for guiding shredded tobacco in a predetermined direction is formed with a generally converging bore therewithin. The converging bore includes a plurality of truncated sections, which have sizes gradually smaller toward the predetermined direction. Each truncated section is defined by a first inner surface 3b1 which has a gradually smaller diameter toward the predetermined direction. Each two adjacent truncated sections define a stepped portion therebetween which has a second inner surface 3b2, which faces the predetermined direction.The first inner surface 3b1 is contiguous to the second inner surface 3b2 which has a gradually larger diameter toward the predetermined direction. At the back of the tongue body 3 is provided a mounting fixture 3a to facilitate the mounting to the equipment.

The shredded tobacco is then forced to be compressed and then relaxed along the guide surfaces 3b1 and 3b2. While the combination of compression and relaxation is repeated, the diameter of the cigarette rod is gradually reduced to the desired size.

In the example embodiment, 35 truncated sections are arranged at 3mm intervals over the entire length 105mm ofthetongue body 3.

The running experiment of the tongue showed that as compared with the conventional type of tongue without the stepped guide portion 3b, the temperature rise of the tongue of the present invention is small, i.e., temperature reduction of more than 20 degress C can be realized. Because of these features of the present invention, it was also confirmed that the formation of tar on the tongue can be effectively prevented.

Investigation into the wear of the tongue of this invention showed that the wear is uniformly distributed over the stepped guide portion 3b. As for the conventional tongue without a stepped guide surface 3b including the first and second inner surfaces 3b1 and 3b2 respectively, wear is conspicuous near the outlet end where the shredded tobacco is compressed at higher pressure. This conforms to what we know from experience. It is accordingly understood that the conventional tongue is overheated near the outlet and due to the heat more tar develops near the outlet than anywhere else.

As can be seen from the foregoing, since the tongue of this invention has the stepped inner surface, the temperature rise of the tongue is limited and the formation of tar on the inner surfaces is prevented. This in turn prevents possible troubles resulting from the tongue. The tongue of this invention can be machined with ease and massproduced woth high accuracy.

Claims (4)

1. A tongue for making cigarette rods comprising a tongue body for guiding shredded tobacco in a predetermined direction, said tongue body being formed with a generally converging bore therewithin, said converging bore including a plurality of truncated sections, said plurality of truncated sections having sizes gradually smaller toward said predetermined direction, each truncated section being defined by a first inner surface having a gradually smaller diameter toward said predetermined direction, each two adjacent truncated section defining a stepped portion therebetween which has a second inner surface, said second inner surface facing said predetermined direction.

2. Atongue according to claim 1,wherein said second inner surface has a gradually larger diameter toward said predetermined direction.

3. Atongue according to claim 2, wherein said first inner surface is contiguous to said second inner surface.

4. A tongue for making cigarette rods substan tally as hereinbefore described with reference to the accompanyimg drawings.