CN110500864A - A kind of weaving drying unit - Google Patents

Abstract

The invention discloses a kind of weaving drying units, including drying box, guide roller and drying lamp, inlet port and outlet port are offered respectively in the middle part of wall at left and right sides of the drying box, the exhaust outlet for vapor to be discharged is equipped at the top of drying box, more guide rollers are installed along S type track spacing in drying box, the more guide rollers are mounted on drying lamp in two sides up and down, drying lamp is installed on mounting plate, the adjusting unit for adjusting drying lamp Yu guide roller distance is also equipped between mounting plate and the tank wall of drying box, the adjusting unit includes Bidirectional-screw, inner thread sleeve and connecting rod, it further include having hot-air seasoning component, the hot-air seasoning component includes exhaust fan and drying box, the application is able to extend distance of the textile in drying box by the S-type arrangement of more guide rollers, to extend drying time, make textile drying more Add sufficiently；Equipped with unit is adjusted, drying temperature is adjusted according to different types of textile, it is adaptable, improve drying efficiency.

Description

A textile drying device

technical field

The invention specifically relates to the technical field of textile drying, in particular to a textile drying device.

Background technique

The original meaning of textile is taken from the general term of spinning and weaving, but with the continuous development and improvement of the textile knowledge system and subject system, especially after the emergence of non-woven textile materials and three-dimensional composite weaving technologies, the current textile is not only a traditional Hand spinning and weaving also include garment, industrial and decorative textiles produced by non-woven technology, modern three-dimensional weaving technology, and modern electrostatic nano-netting technology. Therefore, modern textile refers to a multi-scale structure processing technology of fibers or fiber aggregates. Ancient Chinese textile and printing and dyeing technology has a very long history. As early as the primitive society, the ancients knew how to obtain local materials, use natural resources as raw materials for textile and printing and dyeing, and make simple hand-made textile tools in order to adapt to climate change. Clothing, airbags, curtains and carpets in daily life are all products of weaving, printing and dyeing technology.

In the weaving process, textiles need to be dried, and the drying lamps of existing textile drying devices are generally fixedly installed, so it is difficult to adjust the distance between the drying lamps and products according to different products, and the adaptability is weak.

Contents of the invention

The object of the present invention is to provide a textile drying device to solve the problems raised in the background art above.

To achieve the above object, the present invention provides the following technical solutions:

A textile drying device, comprising a drying box, a guide roller and a drying lamp, the middle parts of the left and right side walls of the drying box are respectively provided with a material inlet and a material outlet, and the top of the drying box is provided with a There are multiple guide rollers installed at intervals along the S-shaped track in the drying box, drying lamps are installed on the upper and lower sides of the multiple guide rollers, and the drying lamps are installed on the mounting plate. An adjustment unit for adjusting the distance between the drying lamp and the guide roller is also installed between the installation plate and the wall of the drying box. The adjustment unit includes a two-way screw rod, an internal thread sleeve and a connecting rod. The two-way screw rod is horizontal It is rotated and installed in the drying box. The threaded sections on both sides of the two-way screw rod are equipped with internal thread sleeves. The internal thread sleeve is threaded with the threaded section of the two-way screw rod. The internal thread sleeve is far away from the side of the mounting plate. Slidingly connected with the box wall of the drying box, the side of the internal thread sleeve close to the mounting plate is hinged with a connecting rod, the other end of the connecting rod is hinged with the mounting plate, and the connecting rods on the two internal thread sleeves are arranged symmetrically .

A further solution: support legs are evenly and symmetrically installed on the bottom of the drying box.

A further solution: both ends of the two-way screw rod are rotatably connected to the fixing plate through bearings, and the fixing plate is installed on the box wall of the drying box through screws.

A further solution: the internal thread sleeve is integrally provided with a slider, and the wall of the drying box is provided with a chute for the slider to slide.

A further solution: a second bevel gear is installed in the middle of the two-way screw rod, a rotating shaft is pierced on the wall of the drying box, and the rotating shaft is connected to the box wall of the drying box through bearings, and the rotating shaft is located in the drying box. A first bevel gear meshed with a second bevel gear is installed at one end.

A further solution: reflective mirrors are installed on the four corners of the drying box.

A further solution: it also includes a hot air drying assembly, the hot air drying assembly includes an exhaust fan and a drying box, the exhaust fan and the drying box are installed on the top of the drying box, and the drying box is provided with a silica gel desiccant. The inlet of the drying box is connected with a suction pipe, and the other end of the suction pipe is connected to the exhaust port. The outlet of the drying box is connected to the air inlet of the exhaust fan through a pipe. The number of the air distribution pipes is the same as that of the guide rollers and corresponds one by one. The other end of the air distribution pipes extends into the guide rollers, and the guide rollers are uniformly provided with a plurality of air holes.

A further solution: ultraviolet lamp beads are also installed on the guide roller, and the ultraviolet lamp beads are distributed equidistantly on the guide roller in the circumferential direction.

A further solution: rollers are installed at the bottom of the supporting legs.

A further solution: the rollers are self-locking rollers.

Compared with prior art, the beneficial effect of the present invention is:

1. In this application, the S-shaped arrangement of multiple guide rollers can extend the distance of textiles in the drying box, thereby prolonging the drying time and making the textiles dry more fully;

2. An adjustment unit is provided, and the adjustment unit includes a two-way screw rod, an internal thread sleeve and a connecting rod. The first bevel gear is driven to rotate by rotating the shaft, and the first bevel gear drives the two-way screw rod to rotate through the second bevel gear. The two-way The threaded rod drives the connecting rod to move through the inner threaded sleeve, and the connecting rod drives the mounting plate close to or away from the guide roller, thereby adjusting the distance between the drying lamp and the textile, and adjusting the drying temperature according to different types of textiles. It has strong adaptability and improves the drying efficiency. dry efficiency;

3. Equipped with a hot air drying assembly, the hot air drying assembly includes an exhaust fan and a drying box. The exhaust fan works, and the exhaust fan sucks the water vapor in the drying box into the drying box through the suction pipe. After drying, it passes through the main dryer again. The air pipe and air distribution pipe are sent into the guide roller, and the textiles are dried by spraying through the air holes, which effectively utilizes the heat of water vapor, avoids the waste of heat, and improves the energy utilization rate.

Description of drawings

Fig. 1 is a schematic structural diagram of a first embodiment of a textile drying device.

Fig. 2 is a schematic structural diagram of a second embodiment of a textile drying device.

Fig. 3 is a schematic structural view of a third embodiment of a textile drying device.

Fig. 4 is a schematic diagram of the distribution of ultraviolet lamp beads in the third embodiment of the textile drying device.

In the figure: 1-drying box, 2-mirror, 3-outlet, 4-guide roller, 5-drying lamp, 6-installation plate, 7-connecting rod, 8-internal threaded sleeve, 9- The first bevel gear, 10-the second bevel gear, 11-two-way screw rod, 12-support leg, 13-roller, 14-feed inlet, 15-drying box, 16-exhauster fan, 17-main air pipe, 18- Tracheal pipe, 19-straw, 20-ultraviolet lamp beads.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

Please refer to Fig. 1, in the embodiment of the present invention, a textile drying device includes a drying box 1, a guide roller 4 and a drying lamp 5, the bottom of the drying box 1 is evenly and symmetrically equipped with supporting legs 12, and the supporting legs 12 bottom end is equipped with roller 13, and described roller 13 is self-locking roller, and the movement of convenience device, described drying box 1 left and right side wall middle parts are provided with feed inlet 14 and discharge port 3 respectively, and drying box 1 1 The top is provided with an exhaust port for discharging water vapor, and multiple guide rollers 4 are installed at intervals along the S-shaped track in the drying box 1, and the multiple guide rollers 4 are arranged in an S-shape to prolong the drying time of textiles in the drying box. 1, so as to prolong the drying time and make the textiles more fully dry. Drying lamps 5 are installed on the upper and lower sides of the plurality of guide rollers 4, and the drying lamps 5 are installed on the mounting plate 6. An adjustment unit for adjusting the distance between the drying lamp 5 and the guide roller 4 is installed between the plate 6 and the wall of the drying box 1. The adjustment unit includes a two-way screw rod 11, an internally threaded sleeve 8 and a connecting rod 7. The two-way screw rod 11 is horizontally rotatably installed in the drying box 1. In this embodiment, the two ends of the two-way screw rod 11 are rotationally connected to the fixing plate through bearings, and the fixing plate is preferably installed in the box of the drying box 1 by screws. On the wall, the threaded section on both sides of the two-way screw rod 11 is equipped with an internally threaded sleeve 8, and the internally threaded sleeve 8 is threadedly connected with the threaded section of the two-way screw rod 11, and the internally threaded sleeve 8 is away from a part of the mounting plate 6. The side is slidingly connected with the box wall of the drying box 1. In this embodiment, the internal thread sleeve 8 is integrally provided with a slider, and the box wall of the drying box 1 is provided with a chute for sliding the slider. The side of the internally threaded sleeve 8 close to the mounting plate 6 is hinged with a connecting rod 7, the other end of the connecting rod 7 is hinged with the mounting plate 6, and the connecting rods 7 on the two internally threaded sleeves 8 are arranged symmetrically. A second bevel gear 10 is installed in the middle of the two-way screw rod 11, and a rotating shaft is pierced on the wall of the drying box 1. There is the first bevel gear 9 meshed with the second bevel gear 10. When in use, the first bevel gear 9 is driven to rotate by rotating the rotating shaft, and the first bevel gear 9 drives the two-way screw rod 11 to rotate through the second bevel gear 10, and the two-way screw rod 11 Drive the connecting rod 7 to move through the internal thread sleeve 8, and the connecting rod 7 drives the mounting plate 6 to approach or move away from the guide roller 4, thereby adjusting the distance between the drying lamp 5 and the textiles, and adjusting the drying temperature according to different types of textiles. Strong, improve the drying efficiency;

Further, reflective mirrors 2 are installed on the four corners of the drying box, and the reflective mirrors 2 further reflect the light of the drying lamp 5 to the textiles to achieve the effect of concentrating light, thus effectively improving the drying efficiency.

Example 2

Please refer to Fig. 2, in the embodiment of the present invention, a textile drying device includes a drying box 1, a guide roller 4 and a drying lamp 5, and the bottom of the drying box 1 is evenly and symmetrically equipped with supporting legs 12, and the supporting legs 12 bottom end is equipped with roller 13, and described roller 13 is self-locking roller, and the movement of convenience device, described drying box 1 left and right side wall middle parts are provided with feed inlet 14 and discharge port 3 respectively, and drying box 1 1 The top is provided with an exhaust port for discharging water vapor, and multiple guide rollers 4 are installed at intervals along the S-shaped track in the drying box 1, and the multiple guide rollers 4 are arranged in an S-shape to prolong the drying time of textiles in the drying box. 1, so as to prolong the drying time and make the textiles more fully dry. Drying lamps 5 are installed on the upper and lower sides of the plurality of guide rollers 4, and the drying lamps 5 are installed on the mounting plate 6. An adjustment unit for adjusting the distance between the drying lamp 5 and the guide roller 4 is installed between the plate 6 and the wall of the drying box 1. The adjustment unit includes a two-way screw rod 11, an internally threaded sleeve 8 and a connecting rod 7. The two-way screw rod 11 is horizontally rotatably installed in the drying box 1. In this embodiment, the two ends of the two-way screw rod 11 are rotationally connected to the fixing plate through bearings, and the fixing plate is preferably installed in the box of the drying box 1 by screws. On the wall, the threaded section on both sides of the two-way screw rod 11 is equipped with an internally threaded sleeve 8, and the internally threaded sleeve 8 is threadedly connected with the threaded section of the two-way screw rod 11, and the internally threaded sleeve 8 is away from a part of the mounting plate 6. The side is slidingly connected with the box wall of the drying box 1. In this embodiment, the internal thread sleeve 8 is integrally provided with a slider, and the box wall of the drying box 1 is provided with a chute for sliding the slider. The side of the internally threaded sleeve 8 close to the mounting plate 6 is hinged with a connecting rod 7, the other end of the connecting rod 7 is hinged with the mounting plate 6, and the connecting rods 7 on the two internally threaded sleeves 8 are arranged symmetrically. A second bevel gear 10 is installed in the middle of the two-way screw rod 11, and a rotating shaft is pierced on the wall of the drying box 1. The rotating shaft is connected to the box wall of the drying box 1 through bearings. There is the first bevel gear 9 meshing with the second bevel gear 10. When in use, the first bevel gear 9 is driven to rotate by rotating the shaft, and the first bevel gear 9 drives the two-way screw 11 to rotate through the second bevel gear 10, and the two-way screw 11 Drive the connecting rod 7 to move through the internal thread sleeve 8, and the connecting rod 7 drives the mounting plate 6 to approach or move away from the guide roller 4, thereby adjusting the distance between the drying lamp 5 and the textiles, and adjusting the drying temperature according to different types of textiles. Strong, improve the drying efficiency;

Further, reflective mirrors 2 are installed on the four corners of the drying box, and the reflective mirrors 2 further reflect the light of the drying lamp 5 to the textiles to achieve the effect of concentrating light, thereby effectively improving the drying efficiency;

Further, in order to further speed up the drying speed and improve the drying efficiency, a hot air drying assembly is also included, and the hot air drying assembly includes an exhaust fan 16 and a drying box 15, and the exhaust fan 16 and the drying box 15 are both Installed on the top of the drying box 1, the drying box 15 is provided with a silica gel desiccant, the inlet of the drying box 15 is connected with a suction pipe 19, the other end of the suction pipe 19 is connected with the exhaust port, and the outlet of the drying box 15 is connected to the exhaust fan 16 through a pipeline. The air inlet is connected, and the air outlet of the exhaust fan 16 is connected with a main air pipe 17, and the main air pipe 17 is connected with a plurality of air distribution pipes 18 through a pipe joint. The other end of 18 extends into the guide roller 4, and the guide roller 4 is evenly provided with a plurality of air holes. When drying, the exhaust fan 16 works, and the exhaust fan 16 sucks the water vapor in the drying box 1 into the drying box 15 through the suction pipe 19. After drying, it is sent into the guide roller 4 again through the main air pipe 17 and the air distribution pipe 18, and the textiles are dried by spraying through the air holes, which effectively utilizes the heat of water vapor, avoids the waste of heat, and improves the energy utilization rate.

Example 3

Please refer to Fig. 3-4, in the embodiment of the present invention, a textile drying device includes a drying box 1, a guide roller 4 and a drying lamp 5, and the bottom of the drying box 1 is evenly and symmetrically equipped with support legs 12, A roller 13 is installed at the bottom of the supporting leg 12, and the roller 13 is a self-locking roller, which facilitates the movement of the device. The middle part of the left and right side walls of the drying box 1 is provided with a feed inlet 14 and a discharge outlet 3 respectively. The top of the drying box 1 is provided with an exhaust port for discharging water vapor. A plurality of guide rollers 4 are installed at intervals along the S-shaped trajectory in the drying box 1. The plurality of guide rollers 4 are arranged in an S-shape to prolong the drying time of textiles. The distance in the drying box 1, so as to prolong the drying time and make the textile drying more fully, the upper and lower sides of the plurality of guide rollers 4 are equipped with drying lamps 5, and the drying lamps 5 are installed on the mounting plate 6 An adjustment unit for adjusting the distance between the drying lamp 5 and the guide roller 4 is also installed between the installation plate 6 and the wall of the drying box 1, and the adjustment unit includes a two-way screw rod 11, an internal thread sleeve 8 and a connecting rod 7. The two-way screw rod 11 is horizontally installed in the drying box 1. In this embodiment, both ends of the two-way screw rod 11 are connected to the fixed plate through bearings. The fixed plate is preferably installed in the drying box 1 by screws. On the box wall of the two-way screw rod 11, the threaded sections on both sides are equipped with an internally threaded sleeve 8, and the internally threaded sleeve 8 is threadedly connected with the threaded section of the two-way screw rod 11, and the internally threaded sleeve 8 is far away from the mounting plate 6 One side of the drying box 1 is slidingly connected with the box wall of the drying box 1. In this embodiment, the internal thread sleeve 8 is integrally provided with a slider, and the box wall of the drying box 1 is provided with a slide for the slider to slide. groove, the side of the internally threaded sleeve 8 close to the mounting plate 6 is hinged with a connecting rod 7, the other end of the connecting rod 7 is hinged with the mounting plate 6, and the connecting rods 7 on the two internally threaded sleeves 8 are arranged symmetrically. The second bevel gear 10 is installed in the middle part of the two-way screw mandrel 11, and the wall of the drying box 1 is pierced with a rotating shaft. One end is installed with the first bevel gear 9 meshed with the second bevel gear 10. When in use, the first bevel gear 9 is driven to rotate by rotating the rotating shaft, and the first bevel gear 9 drives the two-way screw rod 11 to rotate through the second bevel gear 10. Two-way The screw rod 11 drives the connecting rod 7 to move through the internal thread sleeve 8, and the connecting rod 7 drives the mounting plate 6 to approach or move away from the guide roller 4, thereby adjusting the distance between the drying lamp 5 and the textiles, and adjusting the drying temperature according to different types of textiles. Strong adaptability, improved drying efficiency;

Further, reflective mirrors 2 are installed on the four corners of the drying box, and the reflective mirrors 2 further reflect the light of the drying lamp 5 to the textiles to achieve the effect of concentrating light, thereby effectively improving the drying efficiency;

Further, in order to further speed up the drying speed and improve the drying efficiency, a hot air drying assembly is also included, and the hot air drying assembly includes an exhaust fan 16 and a drying box 15, and the exhaust fan 16 and the drying box 15 are both Installed on the top of the drying box 1, the drying box 15 is provided with a silica gel desiccant, the inlet of the drying box 15 is connected with a suction pipe 19, the other end of the suction pipe 19 is connected with the exhaust port, and the outlet of the drying box 15 is connected to the exhaust fan 16 through a pipeline. The air inlet is connected, and the air outlet of the exhaust fan 16 is connected with a main air pipe 17, and the main air pipe 17 is connected with a plurality of air distribution pipes 18 through a pipe joint. The other end of 18 extends into the guide roller 4, and the guide roller 4 is evenly provided with a plurality of air holes. When drying, the exhaust fan 16 works, and the exhaust fan 16 sucks the water vapor in the drying box 1 into the drying box 15 through the suction pipe 19. After drying, it is sent into the guide roller 4 again through the main air pipe 17 and the air distribution pipe 18, and the textiles are dried by blowing out through the air holes, effectively utilizing the heat of water vapor, avoiding the waste of heat, and improving the energy utilization rate;

Furthermore, ultraviolet lamp beads 20 are also installed on the guide roller 4, and the ultraviolet lamp beads 20 are distributed equidistantly on the guide roller 4 in the circumferential direction. Through the ultraviolet lamp beads 20, textiles can be sterilized, thereby having It is beneficial to the storage and transportation of textiles and effectively protects textiles.

The working principle of the present invention is: when the present invention is in use, the distance of the textiles in the drying box 1 can be extended through the S-shaped arrangement of the plurality of guide rollers 4, thereby prolonging the drying time and making the textiles dry more fully. The rotating shaft drives the first bevel gear 9 to rotate, the first bevel gear 9 drives the two-way screw 11 to rotate through the second bevel gear 10, the two-way screw 11 drives the connecting rod 7 to move through the internal thread sleeve 8, and the connecting rod 7 drives the mounting plate 6 close to or away from the guide roller 4, so as to adjust the distance between the drying lamp 5 and the textiles, and adjust the drying temperature according to different types of textiles, which has strong adaptability and improves the drying efficiency. The exhaust fan 16 works, and the exhaust fan 16 will dry The water vapor in the box 1 is sucked into the drying box 15 through the suction pipe 19, and after being dried, it is sent into the guide roller 4 through the main air pipe 17 and the air distribution pipe 18 again, and is sprayed out through the air holes to dry the textiles, effectively utilizing the water vapor. heat, avoiding the waste of heat, and improving the energy utilization rate. Through the ultraviolet lamp beads 20, the textiles can be sterilized, which is beneficial to the storage and transportation of the textiles, and effectively protects the textiles.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. a kind of weaving drying unit, including drying box (1), guide roller (4) and drying lamp (5), drying box (1) left and right two Feed inlet (14) and discharge port (3) are offered in the middle part of side wall respectively, the exhaust for vapor to be discharged is equipped at the top of drying box (1) Mouthful, which is characterized in that more guide rollers (4), the more guide rollers are installed along S type track spacing in the drying box (1) (4) two sides are mounted on drying lamp (5) up and down, and the drying lamp (5) is installed on mounting plate (6), mounting plate (6) and drying box (1) the adjusting unit for adjusting drying lamp (5) Yu guide roller (4) distance is also equipped between tank wall；

The adjusting unit includes Bidirectional-screw (11), inner thread sleeve (8) and connecting rod (7), and the Bidirectional-screw (11) is horizontal It is rotatablely installed in drying box (1), is arranged on the thread segment of Bidirectional-screw (11) two sides and inner thread sleeve (8), internal screw thread Sleeve (8) is threadedly coupled with the thread segment of Bidirectional-screw (11), side and drying of the inner thread sleeve (8) far from mounting plate (6) The tank wall of case (1) is slidably connected, and the inner thread sleeve (8) is hinged with connecting rod (7) close to the side of mounting plate (6), connecting rod (7) Hingedly, the connecting rod (7) on two inner thread sleeves (8) is symmetrical arranged for the other end and mounting plate (6).

2. weaving drying unit according to claim 1, which is characterized in that symmetrically pacify drying box (1) bottom Equipped with supporting leg (12).

3. weaving drying unit according to claim 1, which is characterized in that Bidirectional-screw (11) both ends pass through bearing It is rotatablely connected with fixed plate, fixed plate is installed on the tank wall of drying box (1) by screw.

4. weaving drying unit according to claim 1, which is characterized in that integral type is set on the inner thread sleeve (8) There is sliding block, the sliding slot for sliding block sliding is offered on the tank wall of drying box (1).

5. weaving drying unit according to claim 3, which is characterized in that be equipped with the in the middle part of the Bidirectional-screw (11) Two bevel gears (10) are equipped with shaft on the tank wall of drying box (1), and shaft is rotated by bearing and the tank wall of drying box (1) to be connected It connects, one end that shaft is located in drying box (1) is equipped with the first bevel gear (9) engaged with second bevel gear (10).

6. -5 any weaving drying unit according to claim 1, which is characterized in that the drying box is pacified on four angles Equipped with reflective mirror (2).

7. weaving drying unit according to claim 6, which is characterized in that it further include having hot-air seasoning component, the heat It includes exhaust fan (16) and drying box (15) that wind, which dries component, and the exhaust fan (16) and drying box (15) are mounted on drying box (1) top, drying box (15) is interior to be equipped with silica-gel desiccant, and the import of drying box (15) is connected with suction pipe (19), and suction pipe (19) is another One end is connect with exhaust outlet, and the outlet of drying box (15) is connect by pipeline with the air inlet of exhaust fan (16), exhaust fan (16) Air outlet on be connected with main tracheae (17), main tracheae (17) is connected with more gas-distributing pipes (18), gas-distributing pipe by pipe joint (18) quantity is identical as the quantity of guide roller (4) and corresponds, and gas-distributing pipe (18) other end extends in guide roller (4), Guide roller is uniformly provided with multiple stomatas on (4).

8. weaving drying unit according to claim 7, which is characterized in that be also equipped on the guide roller (4) ultraviolet Line lamp bead (20), ultraviolet light lamp bead (20) circumferential direction be equally spaced with guide roller (4) on.

9. weaving drying unit according to claim 2, which is characterized in that supporting leg (12) bottom end is equipped with idler wheel (13)。

10. weaving drying unit according to claim 9, which is characterized in that the idler wheel (13) is self-locking idler wheel.