Coal mine underground antiskid ergonomics rubber boots

Abstract

The present application belongs to the technical field of antiskid shoes, and provides a coal mine underground antiskid ergonomics rubber boots, which comprises a shoe sole, an antiskid executing mechanism arranged on the shoe sole, and the antiskid executing mechanism is used for preventing people from falling down in a wet environment; the antiskid executing mechanism comprises an antiskid component and an executing component, wherein the antiskid component and the executing component are arranged in a box body; when the tunnel is in a normal environment, the executing component is used for monitoring the moisture degree in the tunnel; when the tunnel is wet, the executing component feeds back the monitored information to the antiskid component, the antiskid component acts to increase the friction, and the people are prevented from falling down in the wet environment. The present application can change the friction between the shoe sole and the ground in time according to the moisture condition of the ground, so as to achieve the effect of antiskid.

Description

Technical Field

[0001] This invention belongs to the field of anti-slip shoe technology, and in particular relates to an anti-slip ergonomic rubber boot for underground coal mines. Background Technology

[0002] With the development of my country's economy and technology, the demand for energy resources is increasing, especially for coal resources. Consequently, coal mining has also increased. Currently, coal mining is generally carried out using semi-mechanized methods, requiring miners to work for extended periods in the mines. When walking in damp mines, miners are prone to slipping and falling due to the slippery surface. Existing rubber shoes worn by miners primarily rely on sole patterns and materials to increase traction and provide slip resistance. However, these shoes are almost ineffective on wet, hardened mine tunnel surfaces, offering less than ideal slip resistance. Therefore, there is an urgent need for a new type of ergonomic, non-slip rubber boot designed for underground coal mines that better adapts to the characteristics of the environment and prevents miners from slipping and falling on wet surfaces. Summary of the Invention

[0003] The purpose of this invention is to provide an anti-slip ergonomic rubber boot for underground coal mines, in order to solve the above-mentioned problems, adapt to the characteristics of underground coal mines, and better prevent coal miners from falling due to slippery ground.

[0004] To achieve the above objectives, the present invention provides the following solution: a non-slip ergonomic rubber boot for underground coal mines, comprising a sole, wherein a non-slip actuator is provided on the sole, the non-slip actuator being used to prevent a person from falling in a wet environment;

[0005] An anti-slip actuator, comprising an anti-slip component and an actuation component, wherein the anti-slip component and the actuation component are disposed within the housing;

[0006] When the environment inside the tunnel is normal, the execution component is used to monitor the moisture level inside the tunnel;

[0007] When the tunnel is wet, the actuator will feed back the monitored information to the anti-slip component, which will then increase friction to prevent people from falling in wet conditions.

[0008] Preferably, the anti-slip component includes a housing, a drive unit, and an anti-slip actuator. The housing is fixedly connected to the sole of the shoe, and the bottom of the housing is flush with the bottom of the sole. The drive unit and the anti-slip actuator are disposed within the housing and are connected in a transmission manner. The actuator includes a sensing unit, an electronic control unit, and an energy storage unit. The sensing unit is used to monitor whether the sole is in a damp area within the aisle and transmits the monitoring information to the electronic control unit. The electronic control unit is electrically connected to the drive unit and is used to control the drive unit to perform corresponding actions.

[0009] Preferably, the drive unit includes a worm gear rotatably connected to the housing, a plurality of anti-slip parts being respectively connected to the worm gear, a micro motor being fixedly connected to the housing, the output shaft of the micro motor being coaxially fixedly connected to one end of the worm gear, and the electronic control unit being electrically connected to the micro motor.

[0010] Preferably, the anti-slip actuator includes a worm gear and a guide sleeve. The guide sleeve is vertically rotatably connected to the bottom wall of the box body. The bottom of the worm gear is fixedly connected to the top of the guide sleeve. The worm gear and the guide sleeve are coaxially arranged. The top of the worm gear is rotatably connected to the bottom of the shoe sole. A groove is vertically formed in the center of the bottom of the worm gear. One end of a pin is connected to the groove. A telescopic hole is formed on the bottom wall of the box body. The other end of the pin is vertically slidably connected between the telescopic hole and the guide sleeve and is positioned corresponding to the ground. The worm gear meshes with the worm.

[0011] Preferably, the electronic control unit includes a central processing chip, which is fixedly connected to the housing, and the sensing unit and the micro motor are electrically connected to the central processing chip respectively.

[0012] Preferably, the sensing unit includes a plurality of humidity sensors fixedly embedded on the bottom wall of the box, the plurality of humidity sensors being disposed corresponding to the ground, and the central processing chip being electrically connected to the plurality of humidity sensors.

[0013] Preferably, the energy storage component includes a battery fixedly connected to the housing, the battery providing the power required for the operation of the central processing chip, the micro motor and the humidity sensors.

[0014] Preferably, the centers of the plurality of worm gears are located on the same horizontal plane and are evenly distributed on both sides of the worm.

[0015] Compared with existing technologies, this invention has the following advantages and technical effects: The main function of the anti-slip component is to maintain a low friction when the sole is on a dry surface, and to change the contact form between the sole 1 and the ground when the sole is on a wet, slippery surface, thereby increasing friction. The main function of the actuator is to monitor the ground moisture level in real time and control the anti-slip component to operate when the ground humidity exceeds a set value, thus enabling the anti-slip component to change the friction. Overall, this invention can, according to the environment in the alleyway, monitor the humidity of the ground where the sole is located, control the contact form between the sole and the ground in real time, change the friction between the sole and the ground, and thus achieve an anti-slip effect. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the sole of the shoe according to the present invention;

[0018] Figure 2 This is a schematic diagram of the anti-slip actuator of the present invention;

[0019] Figure 3 This is a schematic diagram of the anti-slip part of the present invention;

[0020] Figure 4 This is a schematic diagram showing the installation relationship between the box body, anti-slip components, and shoe sole of the present invention;

[0021] Figure 5 This is a schematic diagram showing the pin states on dry and wet road surfaces according to the present invention.

[0022] Figure 6 This is a schematic diagram of the inflation / deflation unit in Embodiment 2 of the present invention;

[0023] Figure 7 This is a schematic diagram of the telescopic airbag and shock absorber in Embodiment 2 of the present invention;

[0024] The components include: 1. Shoe sole; 2. Anti-slip actuator; 3. Housing; 4. Worm gear; 5. Anti-slip actuator; 6. Humidity sensor; 7. Bearing housing; 8. Bearing; 9. Central processing chip; 10. Micro motor; 11. Battery; 12. Thrust bearing; 13. Worm gear; 14. Pin; 15. Guide sleeve; 16. Shock absorber; 17. Main airbag; 18. Fixing sleeve; 19. Pressure plate; 20. Pressure rod; 21. Push block; 22. Lead screw; 23. Air tube; 24. Telescopic airbag. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1:

[0028] Reference Figures 1-5 As shown, the present invention provides an anti-slip ergonomic rubber boot for underground coal mines, including a sole 1, on which an anti-slip actuator 2 is provided. The anti-slip actuator 2 is used to prevent people from falling in wet environments.

[0029] Anti-slip actuator 2, which includes an anti-slip component and an actuator component, wherein the anti-slip component and the actuator component are disposed inside the housing 3;

[0030] When the environment inside the tunnel is normal, the execution component is used to monitor the moisture level inside the tunnel.

[0031] When the tunnel is wet, the actuator will send the monitored information to the anti-slip component, which will then increase friction to prevent people from falling in wet conditions.

[0032] The main function of the anti-slip component is to maintain a low friction when the sole 1 is on a dry surface, and to change the contact pattern between the sole 1 and the ground to increase friction when the sole 1 is on a wet, slippery surface. The main function of the actuator is to monitor the moisture level of the ground in real time and control the anti-slip component to operate when the ground moisture value exceeds a set value, thereby enabling the anti-slip component to change the friction. Overall, this invention can achieve an anti-slip effect by monitoring the moisture value of the ground where the sole is located, and controlling the contact pattern between the sole and the ground in real time according to the environment in the alley.

[0033] The solution is further optimized. The anti-slip component includes a housing 3, a drive unit, and an anti-slip actuator 5. The housing 3 is fixedly connected to the sole 1, and the bottom of the housing 3 is flush with the bottom of the sole 1. The drive unit and the anti-slip actuator 5 are located inside the housing 3 and are connected by transmission. The actuator includes a sensing unit, an electronic control unit, and an energy storage unit. The sensing unit is used to monitor whether the sole 1 is in a damp area in the aisle and transmits the monitoring information to the electronic control unit. The electronic control unit is electrically connected to the drive unit and is used to control the drive unit to perform corresponding actions.

[0034] The scheme is further optimized. The drive unit includes a worm gear 4 rotatably connected inside the housing 3. Several anti-slip parts 5 are respectively connected to the worm gear 4 for transmission. A micro motor 10 is fixedly connected inside the housing 3. The output shaft of the micro motor 10 is coaxially fixedly connected to one end of the worm gear 4. The electrical control unit is electrically connected to the micro motor 10.

[0035] Further optimizing the design, the anti-slip actuator 5 includes a worm gear 13 and a guide sleeve 15. The guide sleeve 15 is vertically rotatably connected to the bottom wall of the box 3. The bottom of the worm gear 13 is fixedly connected to the top of the guide sleeve 15. The worm gear 13 and the guide sleeve 15 are coaxially arranged. The top of the worm gear 13 is rotatably connected to the bottom of the shoe sole 1. A groove is vertically opened in the center of the bottom of the worm gear 13. One end of the pin 14 is connected to the groove. A telescopic hole is opened on the bottom wall of the box 3. The other end of the pin 14 is vertically slidably connected between the telescopic hole and the guide sleeve 15 and is correspondingly set to the ground. The worm gear 13 meshes with the worm 4.

[0036] In a further optimized design, the top of the worm gear 13 is connected to the bottom of the shoe sole 1, and the guide sleeve 15 is connected to the bottom wall of the housing 3, respectively, via thrust bearings 12. Specifically, as follows... Figure 2 As shown in Figure I, the tight ring of the thrust bearing 12 between the worm gear 13 and the shoe sole 1 abuts against the top of the worm gear 13, and the loose ring of the thrust bearing 12 is fixedly connected to the shoe sole 1. The tight ring of the thrust bearing 12 between the guide sleeve 15 and the box body 3 is fixedly connected to the outer wall of the guide sleeve 15, and the loose ring of the thrust bearing 12 is fixedly connected to the bottom wall of the box body 3. Figure 2 As shown in II, two sets of bearing seats 7 are provided inside the box body 3. Bearings 8 are fixedly embedded in the bearing seats 7. The two sets of bearings 8 are respectively fixedly sleeved on both ends of the worm gear 4, so as to fix the worm gear 4 inside the box body 3 while allowing the worm gear 4 to rotate smoothly.

[0037] In a further optimized design, threads are provided on the inner wall of the groove of the worm gear 13 and on the side wall of the pin 14 located in the groove. The pin 14 is connected to the groove through threaded transmission.

[0038] like Figure 3As shown, when the sensing unit detects that the ground where the sole 1 is located is wet, the sensing component transmits the monitoring information to the electronic control unit. The electronic control unit controls the micro motor 10 to rotate, and the rotation of the micro motor 10 drives several worm gears 4 to rotate. When the worm gears 4 rotate, they drive several worm wheels 13 inside the housing 3 to rotate clockwise simultaneously through threaded transmission. Figure 3 As shown in Figure I. Since the pin 14 can only slide vertically within the telescopic hole, when the worm gear 13 rotates clockwise, it generates relative rotation with the pin 14. Under the action of threaded transmission, the pin 14 moves downward along the telescopic hole and extends out of the box 3. By changing the contact form between the sole 1 and the ground through several extended pins 14, the gripping effect on the ground is improved, thereby increasing friction. Since the transmission method of the worm gear is unidirectional, the worm gear 13 cannot drive the worm 4 to rotate in the opposite direction. Therefore, when a person walks, the pin 14 will not retract into the box 3 due to pressure, thus providing stable grip on wet and slippery surfaces. When the sole 1 is placed on dry ground again, the sensing unit transmits the monitoring information to the electronic control unit. The electronic control unit controls the micro motor 10 to reverse, causing several worm gears 13 to rotate counterclockwise through the worm 4, as shown in Figure I. Figure 3 As shown in II, the worm gear 13 moves the pin 14 upward through the threaded drive, and then retracts it back into the housing 3.

[0039] The solution is further optimized so that the electronic control unit includes a central processing chip 9, which is fixedly connected inside the housing 3. The sensing unit and the micro motor 10 are electrically connected to the central processing chip 9.

[0040] The solution is further optimized. The sensing unit includes several humidity sensors 6 that are fixedly embedded on the bottom wall of the box 3. The humidity sensors 6 are set in relation to the ground. The central processing chip 9 is electrically connected to the humidity sensors 6.

[0041] Humidity sensor 6 collects the humidity value of the surrounding ground environment and transmits the collected humidity value to central processing chip 9. Central processing chip 9 judges the humidity value. When the humidity value is less than the set value, micro motor 10 does not move. When the humidity value is greater than the set value, central processing chip 9 controls micro motor 10 to rotate. Through the transmission of worm gear 13 and worm 4, the pin extends out of the box 3.

[0042] The solution is further optimized so that the energy storage component includes a battery 11 fixedly connected inside the housing 3. The battery 11 provides the power required for the operation of the central processing chip 9, the micro motor 10 and several humidity sensors 6.

[0043] In a further optimized design, the centers of several worm gears 13 are located on the same horizontal plane and are evenly distributed on both sides of the worm 4.

[0044] The evenly distributed worm gears 13 ensure that the pins 14 are also evenly distributed on the bottom surface of the box 3 after they extend, so that the sole 1 can make stable contact with the ground and avoid the situation where one side of the sole is higher than the other side after several pins 14 extend.

[0045] The design was further optimized by fixing the box 3 and the shoe sole 1 together with several screws.

[0046] The screw connection ensures a reliable connection between the box 3 and the sole 1, preventing the box 3 from falling off when workers are wearing and walking. At the same time, the screw connection makes it easy to remove the box 3 from the sole 1, facilitating maintenance and repair of the internal structure of the box 3 or replacement of the battery 11.

[0047] The working process of this embodiment is as follows: Workers wear the rubber boots of this invention and walk on them. The humidity sensor 6 monitors the humidity value of the ground at the sole 1 in real time. When walking on dry ground, the humidity sensor 6 transmits the collected humidity value to the central processing chip 9. The central processing chip 9 determines that the humidity value is less than a set value, and the micro motor 10 does not operate. When walking on wet and slippery ground, the humidity sensor 6 transmits the collected humidity value to the central processing chip 9. The central processing chip 9 determines that the humidity value is greater than the set value and controls the micro motor 10 to operate. When the micro motor 10 rotates, it drives the worm gear 13 to rotate through the worm 4. The rotation of the worm gear 13 causes the pin 14 to extend out of the housing 3, changing the contact form between the sole 1 and the ground, increasing the grip, and thus improving the friction of the rubber boots.

[0048] Example 2

[0049] like Figure 6 and Figure 7 As shown, the only difference between this embodiment and Embodiment 1 is that a shock-absorbing block 16 is vertically slidably connected to the bottom edge of the box 3, and a number of telescopic airbags 24 are abutted between the top of the shock-absorbing block 16 and the sole 1. An inflation / deflation unit is provided between the telescopic airbags 24 and the worm gear 4.

[0050] The scheme is further optimized. The inflation / deflation unit includes a lead screw 22 rotatably connected inside the box body 3. The end of the worm gear 4 away from the micro motor 10 is fixedly connected to one end of the lead screw 22 on the same axis. A push block 21 is driven on the lead screw 22. Pressure rods 20 are fixedly connected to both ends of the push block 21. Two sets of fixing sleeves 18 are fixedly connected to the side wall of the box body 3 near the lead screw 22. Pressure plates 19 are slidably connected inside the two sets of fixing sleeves 18. A main airbag 17 is abutted between the pressure plate 19 and the bottom of the fixing sleeve 18. The two sets of main airbags 17 are respectively connected to several telescopic airbags 24. The side of the pressure plate 19 away from the main airbag 17 is fixedly connected to the end of the pressure rod 20 away from the push block 21.

[0051] The working process of this embodiment is as follows: Figure 6 As shown Figure 5 The diagram shows state b, i.e., the inflation / deflation unit when pin 14 extends out of box 3. Specifically, when sole 1 is on a slippery surface, humidity sensor 6 transmits the humidity value to central processing chip 9. Central processing chip 9 controls micro motor 10 to drive worm gear 4 to rotate. Worm gear 4 drives worm wheel 13 to extend pin 14. At the same time, worm gear 4 drives coaxially connected lead screw 22 to rotate. When lead screw 22 rotates, it drives push block 21 to move closer to worm gear 4 through threaded transmission. As push block 21 moves, push block 21 pulls pressure plate 19 away from the bottom of fixed sleeve 18 through pressure rod 20, so that pressure plate 19 no longer squeezes main airbag 17. Gas in several telescopic airbags 24 flows back to the two sets of main airbags 17 through air tube 23, causing main airbag 17 to inflate and telescopic airbags 24 to retract. The retraction of the telescopic airbag 24 can pull the shock absorber 16 into the box 3, so that when the sole 1 is on a wet ground, several pins 14 are in contact with the ground, and the shock absorber 16 is not in contact with the ground.

[0052] Figure 7 As shown Figure 5 The diagram illustrates state a, where pin 14 retracts into housing 3 and shock absorber 16 extends out of housing 3. Specifically, when sole 1 is back on dry ground, humidity sensor 6 transmits humidity value to central processing chip 9. Central processing chip 9 controls micro motor 10 to drive worm gear 4 to rotate in the opposite direction. Worm gear 4 drives worm wheel 13 to retract pin 14 into housing 3. Simultaneously, worm gear 4 drives coaxially connected lead screw 22 to rotate in the opposite direction. When lead screw 22 rotates, it drives push block 21 to move away from worm gear 4 through threaded transmission. As push block 21 moves, push block 21 drives pressure plate 19 to squeeze main airbag 17 into fixed sleeve 18 through pressure rod 20. After the two sets of main airbags 17 are compressed, the gas inside them is filled into several telescopic airbags 24 through air tube 23. After the telescopic airbags 24 expand and extend, they push shock absorber 16 out of housing 3. At this time, since pin 14 has retracted into housing 3, shock absorber 16 will directly contact the ground. Since the telescopic airbag 24 is filled with gas, it has a certain elasticity. Through the shock absorption effect of several telescopic airbags 24 between the shock-absorbing block 16 and the sole 1, the comfort of wearing rubber boots on dry ground can be improved, and the discomfort caused by the addition of the box 3 can be reduced.

[0053] Because the lead screw 22 has a unidirectional transmission characteristic, when walking on dry ground, the push block 21 can always be in a position away from the worm gear 4, so that the pressure plate 19 is in a state of squeezing the main air bladder 17, thereby avoiding the situation where the shock absorber block 16 retracts into the box body 3 due to the reduction of the gas volume in the telescopic air bladder 24 caused by the expansion of the main air bladder 17.

[0054] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0055] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A type of anti-slip ergonomic rubber boot for underground coal mines, comprising a sole (1), characterized in that, The sole (1) is provided with an anti-slip mechanism (2), which is used to prevent people from falling in wet environments; Anti-slip actuator (2), the anti-slip actuator (2) includes an anti-slip component and an actuator component, wherein the anti-slip component and the actuator component are disposed inside the housing (3); When the environment inside the tunnel is normal, the execution component is used to monitor the moisture level inside the tunnel; When the tunnel is wet, the actuator will feed back the monitored information to the anti-slip component, which will then increase friction to prevent people from falling in wet conditions. The anti-slip assembly includes a housing (3), a drive unit, and an anti-slip actuator (5). The housing (3) is fixedly connected to the sole (1). The bottom of the housing (3) is flush with the bottom of the sole (1). The drive unit and the anti-slip actuator (5) are disposed inside the housing (3). The drive unit and the anti-slip actuator (5) are connected in a transmission manner. The actuator includes a sensing unit, an electronic control unit, and an energy storage unit. The sensing unit is used to monitor whether the sole (1) is in a damp area in the alley and transmits the monitoring information to the electronic control unit. The electronic control unit is electrically connected to the drive unit and is used to control the drive unit to perform corresponding actions. The drive unit includes a worm gear (4) rotatably connected inside the housing (3), and a plurality of anti-slip actuators (5) are respectively connected to the worm gear (4) for transmission. A micro motor (10) is fixedly connected inside the housing (3). The output shaft of the micro motor (10) is fixedly connected to one end of the worm gear (4) along the same axis. The electrical control unit is electrically connected to the micro motor (10). The bottom edge of the box (3) is vertically connected to a shock-absorbing block (16), and the top of the shock-absorbing block (16) and the sole (1) are in contact with a number of telescopic airbags (24). An inflation / deflation unit is provided between the telescopic airbags (24) and the worm gear (4). The inflation / deflation unit includes a lead screw (22) rotatably connected inside the housing (3). The end of the worm gear (4) away from the micro motor (10) is coaxially fixedly connected to one end of the lead screw (22). A push block (21) is driven on the lead screw (22). A pressure rod (20) is fixedly connected to both ends of the push block (21). Two sets of fixed sleeves (18) are fixedly connected to the side wall of the housing (3) near the lead screw (22). A pressure plate (19) is slidably connected inside the two sets of fixed sleeves (18). A main airbag (17) abuts between the pressure plate (19) and the bottom of the fixed sleeve (18). The two sets of main airbags (17) are respectively connected to several telescopic airbags (24). The side of the pressure plate (19) away from the main airbag (17) is fixedly connected to the end of the pressure rod (20) away from the push block (21).

2. The anti-slip ergonomic rubber boot for underground coal mines according to claim 1, characterized in that: The anti-slip actuator (5) includes a worm gear (13) and a guide sleeve (15). The guide sleeve (15) is vertically rotatably connected to the bottom wall of the box (3). The bottom of the worm gear (13) is fixedly connected to the top of the guide sleeve (15). The worm gear (13) and the guide sleeve (15) are coaxially arranged. The top of the worm gear (13) is rotatably connected to the bottom of the shoe sole (1). A groove is vertically opened in the center of the bottom of the worm gear (13). One end of the pin (14) is connected in the groove. A telescopic hole is opened on the bottom wall of the box (3). The other end of the pin (14) is vertically slidably connected between the telescopic hole and the guide sleeve (15) and is corresponding to the ground. The worm gear (13) meshes with the worm (4).

3. The anti-slip ergonomic rubber boot for underground coal mines according to claim 1, characterized in that: The electronic control unit includes a central processing chip (9), which is fixedly connected inside the housing (3). The sensing unit and the micro motor (10) are electrically connected to the central processing chip (9).

4. The anti-slip ergonomic rubber boot for underground coal mines according to claim 3, characterized in that: The sensing unit includes several humidity sensors (6) fixedly embedded on the bottom wall of the box (3), and the several humidity sensors (6) are arranged corresponding to the ground. The central processing chip (9) is electrically connected to the several humidity sensors (6).

5. The anti-slip ergonomic rubber boot for underground coal mines according to claim 4, characterized in that: The energy storage component includes a battery (11) fixedly connected inside the housing (3), which provides the power required for the operation of the central processing chip (9), the micro motor (10) and several humidity sensors (6).

6. The anti-slip ergonomic rubber boot for underground coal mines according to claim 2, characterized in that: The centers of several of the worm gears (13) are located on the same horizontal plane and are evenly distributed on both sides of the worm (4).

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