A fan coil unit for air conditioning system

Abstract

The present invention belongs to the field of air conditioning system technology, and in particular, relates to a fan coil unit of an air conditioning system, including a chassis with an opening at the upper end, the upper end cover of the chassis is provided with a chassis cover, the front end of the chassis is provided with an air outlet, the rear end of the chassis is provided with two rectangular pipe-through openings that are spaced apart from each other, the two pipe-through openings are provided with rectangular air inlet ducts, the rear ends of the two air inlet ducts extend out of the pipe-through openings and are connected to a wind box, the wind box is rotatably connected with an impeller, and the chassis is provided with two installation mechanisms spaced apart from each other, and the installation mechanism is composed of three support vertical blocks that are equally spaced. The advantage is that the present invention can automatically clean the refrigerant coil, and effectively collect the sewage in the chassis, thereby ensuring the effective operation of the air conditioning system.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning systems, and in particular to a fan coil unit of an air conditioning system. Background Art

[0002] The fan coil unit in the air conditioning system is the most commonly used terminal equipment of commercial air conditioners in the market. The working principle of the fan coil unit is: the fan in the unit continuously circulates the air in the room, so that it continuously passes through the coil that supplies cold water or hot water, and is continuously cooled or heated to maintain the temperature in the room.

[0003] During operation, the existing fan disc unit will draw outside air into the air conditioning box with strong power, so that the air contacts the coil to exchange heat. However, during the cooling process, if the humidity in the ambient air is high, small water droplets will condense on the surface of the coil. In most cases, the small water droplets will drip from the surface of the coil and gather at the bottom of the box for discharge. If the air contains dust and impurities, the dust passing through the coil will be sucked in by the small water droplets, forming stains attached to the surface of the coil. Over time, the surface of the coil will be covered with dust, greatly reducing the cooling and heating effects.

[0004] To solve the above problems, we propose a fan coil unit for an air conditioning system. Summary of the invention

[0005] The purpose of the present invention is to solve the problems in the background technology and to propose a fan coil unit for an air conditioning system.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a fan coil unit of an air conditioning system, comprising a chassis with an opening at the upper end, the upper end cover of the chassis is provided with a chassis cover, the front end of the chassis is provided with an air outlet, the rear end of the chassis is provided with two rectangular pipe-through openings distributed at intervals on the left and right, the two pipe-through openings are provided with rectangular air inlet ducts, the rear ends of the two air inlet ducts extend out of the pipe-through openings and are connected to a wind box, and an impeller is rotatably connected in the wind box;

[0007] The chassis is provided with two installation mechanisms arranged at intervals in front and back, and the installation mechanisms are composed of three support vertical blocks distributed at equal intervals. The support vertical blocks located on both sides are arranged close to the inner walls of both sides of the chassis, and each of the installation mechanisms is provided with a refrigerant coil, and the refrigerant coil is transversely fixed and penetrates the corresponding three support vertical blocks, and the refrigerant coil between every two left and right opposite support vertical blocks is a temperature exchange zone;

[0008] A cleaning mechanism is provided in the chassis, and the cleaning mechanism includes cleaning plates located in four temperature exchange intervals, and each temperature exchange interval is provided with two cleaning plates symmetrically arranged on the left and right, and each horizontal cross tube of the refrigerant coil passes through the corresponding cleaning plates, and two connecting rods are fixedly connected between every two corresponding cleaning plates in front and behind, and the four connecting rods located at the top are fixedly connected with movable vertical plates;

[0009] A moving opening is horizontally opened on the box cover, and the upper ends of the four moving vertical plates are all set through the moving opening. The upper end of the box cover is fixedly connected to a driving box covering the moving opening. A first bidirectional threaded rod is rotatably connected between the inner walls on the left and right sides of the driving box. The four moving vertical plates are all threadedly sleeved on the first bidirectional threaded rod, and a first motor that drives the first bidirectional threaded rod to rotate is fixedly installed on the left side of the driving box.

[0010] In the above-mentioned fan coil unit of an air conditioning system, a rubber sleeve is fixedly connected to the inner wall of the pipe passage, and the rubber sleeve is arranged on the corresponding air inlet duct and is slidably connected thereto.

[0011] In the above-mentioned fan coil unit of an air-conditioning system, a base plate is fixedly connected to the rear end of the chassis and between the two air outlets, four telescopic rods distributed in a rectangular shape are fixedly connected to the rear end of the base plate, the telescopic ends of the four telescopic rods are commonly fixedly connected to a mounting plate, the four telescopic rods are all sleeved with springs, the two ends of the springs are respectively fixedly connected to the base plate and the mounting plate, a double-headed motor is fixedly installed at the rear end of the mounting plate, the two output ends of the double-headed motor are coaxially fixedly connected to drive rods, and the ends of the two drive rods away from the double-headed motor are respectively coaxially fixedly connected to two impellers.

[0012] In the above-mentioned fan coil unit of an air conditioning system, the rear ends of the two wind boxes are fixedly connected with rubber blocks, and the rear ends of the two rubber blocks are commonly fixedly connected with a fixing plate.

[0013] In the above-mentioned fan coil unit of an air-conditioning system, two fixing blocks are fixedly connected to both left and right ends of the chassis.

[0014] In the above-mentioned fan coil unit of an air-conditioning system, the cleaning sleeve is spliced ​​by two combined plates arranged opposite to each other in front and back, and a plurality of evenly distributed semicircular recesses are opened on opposite sides of the two combined plates, and the two corresponding semicircular recesses in the front and back together constitute a circular hole, and each horizontal cross tube of the refrigerant coil passes through the corresponding circular hole, and a semicircular rubber scraper is fixedly connected in each of the semicircular recesses, and the two corresponding rubber scrapers in the front and back together constitute a circular shape and are arranged in contact with the outer wall of the refrigerant coil, and the upper and lower ends of the two combined plates are fixedly connected with connecting end blocks, and the two corresponding connecting end blocks in the front and back are connected by bolts.

[0015] In the above-mentioned fan coil unit of an air-conditioning system, one end of each combined plate away from the adjacent supporting vertical block is fixedly connected to a plurality of inclined guide blocks, each of the guide blocks is located between two adjacent circular holes, and the two corresponding guide blocks in front and behind form a "∧" shape.

[0016] In the above-mentioned fan coil unit of an air-conditioning system, sewage outlets are provided on the inner bottom wall of the chassis and on the left and right sides of the two middle supporting vertical blocks. A sewage collecting box is fixedly connected to the lower end of the chassis. The two sewage outlets are connected to the sewage collecting box. The inner bottom wall of the sewage collecting box is an inclined surface sloping downward from left to right, and a drain pipe is connected to the right end of the sewage collecting box.

[0017] In the above-mentioned fan coil unit of an air-conditioning system, two push rods symmetrically distributed on the left and right are slidably fitted on the inner bottom wall of the chassis, a limiting slide bar is fixedly connected between the left and right inner walls of the chassis and at the front position, the upper ends of the two push rods are fixedly connected with a first set block, the first set block is slidably sleeved on the limiting slide bar, a door-shaped groove block is fixedly connected between the left and right inner walls of the chassis and at the rear position, a second two-way threaded rod located in the door-shaped groove block is rotatably connected in the chassis, the upper ends of the two push rods are fixedly connected with a second set block, the two second blocks are threadedly sleeved on the second two-way threaded rod, and a second motor that drives the second two-way threaded rod to rotate is fixedly installed on the left end of the chassis.

[0018] Compared with the existing technology, the advantages of the fan coil unit of this air conditioning system are:

[0019] By setting a cleaning mechanism, the cleaning sleeve in the cleaning mechanism is set in the temperature exchange zone of the refrigerant coil. After using the fan coil unit to adjust the temperature, it is only necessary to start the first motor, and the first motor drives the first bidirectional threaded rod to rotate. The first bidirectional threaded rod is used to drive the two cleaning sleeves in each temperature exchange zone to move relative to each other, so as to clean the water droplets and dust on the surface of the refrigerant coil in the temperature exchange zone, and make the liquid fall to the bottom of the chassis along the guide block. After cleaning, it is only necessary to drive the second bidirectional threaded rod to rotate by the second motor, and the two liquid pushing rods can be used to push the liquid at the bottom of the chassis to the middle, so that it can effectively flow into the sewage collecting box through the sewage outlet, thereby completing the effective collection of sewage. The cleaning method is simple and convenient, and the effective operation of the air-conditioning system is ensured.

[0020] With the setting of telescopic rod, spring, rubber sleeve and rubber block, when the double-head motor drives the two impellers to rotate at high speed, the vibration generated will be absorbed, thereby reducing the vibration noise generated, so that the air-conditioning system has the effect of shock absorption and noise reduction.

[0021] The cleaning cover is a detachable structure, which is convenient for later replacement and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A front perspective view of a fan coil unit of an air conditioning system proposed by the present invention;

[0023] Figure 2 A three-dimensional diagram of the back of a fan coil unit of an air-conditioning system proposed by the present invention;

[0024] Figure 3 for Figure 2 The enlarged structural diagram at A in the middle;

[0025] Figure 4 A partial structural perspective view of the front side of a fan coil unit of an air conditioning system proposed by the present invention;

[0026] Figure 5 A three-dimensional diagram of a cleaning mechanism in a fan coil unit of an air conditioning system proposed by the present invention;

[0027] Figure 6 This is a structural stereogram of a cleaning sleeve in a fan coil unit of an air conditioning system proposed by the present invention.

[0028] In the figure: 1 chassis, 2 box cover, 3 air outlet, 4 pipe insertion port, 5 base plate, 6 telescopic rod, 7 mounting plate, 8 spring, 9 double-headed motor, 10 air inlet duct, 11 bellows, 12 impeller, 13 drive rod, 14 fixed plate, 15 fixed block, 16 refrigerant coil, 17 support vertical block, 18 cleaning sleeve plate, 181 combination plate, 182 semicircular recess, 183 rubber scraper block, 184 connecting end block, 185 guide block, 19 connecting rod, 20 movable vertical plate, 21 drive box, 22 first two-way threaded rod, 23 first motor, 24 sewage collecting box, 25 sewage outlet, 26 drainage pipe, 27 push liquid rod, 28 limit slide rod, 29 first set of blocks, 30 door-type slot block, 31 second two-way threaded rod, 32 second set of blocks, 33 second motor. DETAILED DESCRIPTION

[0029] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0030] Reference Figure 1-Figure 6 A fan coil unit of an air conditioning system comprises a chassis 1 with an opening at the upper end, a chassis cover 2 is provided on the upper end cover of the chassis 1, an air outlet 3 is provided at the front end of the chassis 1, and two rectangular pipe-through openings 4 are provided at the rear end of the chassis 1, which are spaced apart from each other. A rectangular air inlet duct 10 is provided in each of the two pipe-through openings 4. A rubber sleeve is fixedly connected to the inner wall of the pipe-through opening 4. The rubber sleeve is provided on the corresponding air inlet duct 10 and is slidably connected thereto. The air inlet duct 10 and the fixed rubber sleeve can move in the pipe-through opening 4. The rear ends of the two air inlet ducts 10 extend out of the pipe-through opening 4 and are both connected to a bellows 11. An impeller 12 is rotatably connected in the bellows 11. The impeller 12 rotates to deliver air to the chassis 1 through the fixed air inlet duct 10.

[0031] A base plate 5 is fixedly connected to the rear end of the chassis 1 and between the two air outlets 3. Four telescopic rods 6 distributed in a rectangular shape are fixedly connected to the rear end of the base plate 5. The telescopic ends of the four telescopic rods 6 are commonly fixedly connected to a mounting plate 7. Springs 8 are sleeved on the four telescopic rods 6. The two ends of the spring 8 are respectively fixedly connected to the base plate 5 and the mounting plate 7. A double-headed motor 9 is fixedly installed at the rear end of the mounting plate 7. The two output ends of the double-headed motor 9 are coaxially fixedly connected to drive rods 13. The ends of the two drive rods 13 away from the double-headed motor 9 are respectively coaxially fixedly connected to two impellers 12. The double-headed motor 9 can drive the two impellers 12 to rotate, thereby simultaneously supplying air into the chassis 1 with two air inlet ducts 10.

[0032] The rear ends of the two bellows 11 are fixedly connected with rubber blocks, and the rear ends of the two rubber blocks are commonly fixedly connected with a fixing plate 14. The left and right ends of the chassis 1 are fixedly connected with two fixing blocks 15. The fixing plate 14 is used to support and fix the bellows 11, and the fixing block 15 is used to fix and support the bellows 11. Under the setting of the telescopic rod 6, the spring 8, the rubber sleeve and the rubber block, when the double-headed motor 9 drives the two impellers 12 to rotate at a high speed, the vibration effect generated will be absorbed, thereby reducing the vibration noise generated.

[0033] Two installation mechanisms are arranged in front and back intervals in the chassis 1. The installation mechanisms are composed of three support vertical blocks 17 distributed at equal intervals. The support vertical blocks 17 on both sides are arranged close to the inner walls on both sides of the chassis 1. Each installation mechanism is provided with a refrigerant coil 16. The refrigerant coil 16 is a prior art and is used for the transportation of refrigerant to perform heat exchange. It will not be described in detail here. The refrigerant coil 16 is fixed horizontally and runs through the corresponding three support vertical blocks 17, which plays a role in fixing and supporting the refrigerant coil 16. The refrigerant coil 16 between every two left and right opposite support vertical blocks 17 is a temperature exchange interval, that is, the air passing through this position can perform heat exchange.

[0034] The chassis 1 is provided with a cleaning mechanism, which includes cleaning plates 18 located in four temperature exchange intervals, each temperature exchange interval is provided with two cleaning plates 18 symmetrically arranged on the left and right, each horizontal transverse tube of the refrigerant coil 16 passes through the corresponding cleaning plates 18, and the cleaning plates 18 move laterally in the temperature exchange interval. Two connecting rods 19 are fixedly connected between each two corresponding cleaning plates 18, and the four connecting rods 19 located on the top are fixedly connected with movable vertical plates 20.

[0035] The cleaning sleeve 18 is spliced ​​by two front and back oppositely arranged combination plates 181. The two combination plates 181 are provided with a plurality of evenly distributed semicircular notches 182 on the opposite side. The two corresponding semicircular notches 182 together form a circular hole. Each horizontal transverse tube of the refrigerant coil 16 passes through the corresponding circular hole. A semicircular rubber scraper 183 is fixedly connected in each semicircular notch 182. The two corresponding rubber scrapers 183 together form a circular ring and fit the outer wall of the refrigerant coil 16. The upper and lower ends of the two combination plates 181 are fixedly connected with connecting end blocks 184. The two corresponding connecting end blocks 184 are connected by bolts. The above setting can be used for the installation and removal of the cleaning sleeve 18, which is convenient for subsequent replacement and maintenance work. The setting of the rubber scraper 183 allows the cleaning sleeve 18 to scrape off water droplets and dust on the surface of the refrigerant coil 16 when it moves in the temperature exchange zone to ensure the surface is clean.

[0036] A movable opening is horizontally provided on the box cover 2, and the upper ends of the four movable vertical plates 20 are all penetrated through the movable opening. The upper end of the box cover 2 is fixedly connected to a driving box 21 that covers the movable opening. The first two-way threaded rod 22 is connected to the inner walls on the left and right sides of the driving box 21 for common rotation. The four movable vertical plates 20 are all threadedly sleeved on the first two-way threaded rod 22. A first motor 23 that drives the first two-way threaded rod 22 to rotate is fixedly installed on the left side of the driving box 21. The threads on the first two-way threaded rod 22 are divided into left and right parts. When the first two-way threaded rod 22 rotates, the two movable vertical plates 20 on the left and the two movable vertical plates 20 on the right move relatively. Therefore, when the first motor 23 drives the first two-way threaded rod 22 to rotate, it can drive the two cleaning sleeves 18 located in the same temperature exchange interval to move relatively, and scrape off the water droplets and dust on the surface of the refrigerant coil 16.

[0037] One end of each combined plate 181 away from the adjacent supporting vertical block 17 is fixedly connected with a plurality of inclined guide blocks 185, each guide block 185 is respectively located between two adjacent circular holes, and the two corresponding guide blocks 185 in the front and rear form a "∧" shape. The setting of the guide block 185 makes it convenient for water droplets to flow downward along the guide block 185 during cleaning to avoid accumulation on the refrigerant coil 16 below.

[0038] It should be noted that after the refrigerant coil 16 is in cooling operation, the cleaning mechanism can directly remove the water droplets on its surface. In heating or dusty environments, the staff only needs to spray water at the two impellers 12 to make the water droplets adhere to the refrigerant coil 16, and then use the cleaning mechanism to clean the dust and water droplets on the refrigerant coil 16 together.

[0039] Sewage outlets 25 are provided on the inner bottom wall of the chassis 1 and on the left and right sides of the two middle supporting vertical blocks 17. A sewage collecting box 24 is fixedly connected to the lower end of the chassis 1. The two sewage outlets 25 are connected to the sewage collecting box 24. The inner bottom wall of the sewage collecting box 24 is an inclined surface sloping downward from left to right. A drain pipe 26 is connected to the right end of the sewage collecting box 24. The sewage collecting box 24 can collect the liquid flowing down from the refrigerant coil 16, so as to discharge it centrally.

[0040] Two push rods 27 symmetrically distributed on the inner bottom wall of the chassis 1 are slidably attached, and a limit slide bar 28 is fixedly connected between the left and right inner walls of the chassis 1 and at the front position. The upper ends of the two push rods 27 are fixedly connected to a first set block 29, and the first set block 29 is slidably sleeved on the limit slide bar 28 to play a limiting role. A door-shaped slot block 30 is fixedly connected between the left and right inner walls of the chassis 1 and at the rear position. A second bidirectional threaded rod 31 located in the door-shaped slot block 30 is rotatably connected in the chassis 1, and the door-shaped slot block 30 plays a role in protecting the second bidirectional threaded rod 31 to prevent dust from adhering to it. The upper ends of the two liquid pushing rods 27 are fixedly connected with the second sets of blocks 32, and the two second sets of blocks 32 are threadedly sleeved on the second bidirectional threaded rod 31. The left end of the chassis 1 is fixedly installed with a second motor 33 that drives the second bidirectional threaded rod 31 to rotate. When the motor 33 drives the second bidirectional threaded rod 31 to rotate, it can drive the two second sets of blocks 32 to move relative to each other, thereby driving the two liquid pushing rods 27 to move relative to each other. The relatively moving liquid pushing rods 27 can push the waste liquid at the bottom of the chassis 1 to the sewage outlet 25, thereby completing the collection work more effectively.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fan coil unit for an air conditioning system, comprising a case (1) with an opening at the upper end, characterized in that: The upper end cover of the chassis (1) is provided with a chassis cover (2), the front end of the chassis (1) is provided with an air outlet (3), the rear end of the chassis (1) is provided with two rectangular pipe openings (4) spaced apart from each other on the left and right, the two pipe openings (4) are each provided with a rectangular air inlet duct (10), the rear ends of the two air inlet ducts (10) extend out of the pipe openings (4) and are both connected to a wind box (11), and an impeller (12) is rotatably connected to the wind box (11); The chassis (1) is provided with two installation mechanisms arranged at intervals in front and back, the installation mechanisms are composed of three support vertical blocks (17) distributed at equal intervals, the support vertical blocks (17) located on both sides are arranged close to the inner walls of both sides of the chassis (1), each of the installation mechanisms is provided with a refrigerant coil (16), the refrigerant coil (16) is transversely fixed and penetrates the corresponding three support vertical blocks (17), and the refrigerant coil (16) between every two left and right opposite support vertical blocks (17) is a temperature exchange zone; The chassis (1) is provided with a cleaning mechanism, the cleaning mechanism comprising cleaning plates (18) located in four temperature exchange intervals, each of the temperature exchange intervals being provided with two cleaning plates (18) symmetrically arranged on the left and right, each horizontal cross tube of the refrigerant coil (16) passing through a corresponding cleaning plate (18), two connecting rods (19) being fixedly connected between each two front and rear corresponding cleaning plates (18), and the four connecting rods (19) located at the top being fixedly connected to a movable vertical plate (20); The cleaning sleeve (18) is spliced ​​by two front-to-back oppositely arranged combination plates (181), and a plurality of evenly distributed semicircular recesses (182) are provided on opposite sides of the two combination plates (181), and the two front-to-back corresponding semicircular recesses (182) together form a circular hole, and each horizontal cross tube of the refrigerant coil (16) passes through the corresponding circular hole, and a semicircular ring-shaped rubber scraper (183) is fixedly connected in each semicircular recess (182), and the two front-to-back corresponding rubber scrapers (183) together form a circular ring and are arranged to fit the outer wall of the refrigerant coil (16), and the upper and lower ends of the two combination plates (181) are fixedly connected with connecting end blocks (184), and the two front-to-back corresponding connecting end blocks (184) are connected by bolts; One end of each of the combined plates (181) away from the adjacent supporting vertical block (17) is fixedly connected to a plurality of obliquely arranged guide blocks (185), each of the guide blocks (185) is located between two adjacent circular holes, and two corresponding guide blocks (185) at the front and rear form a "∧" shape; The box cover (2) has a movable opening transversely opened, and the upper ends of the four movable vertical plates (20) are all arranged to penetrate the movable opening. The upper end of the box cover (2) is fixedly connected to a driving box (21) covering the movable opening, and a first bidirectional threaded rod (22) is rotatably connected between the inner walls on the left and right sides of the driving box (21). The four movable vertical plates (20) are all threadedly sleeved on the first bidirectional threaded rod (22), and a first motor (23) for driving the first bidirectional threaded rod (22) to rotate is fixedly installed on the left side of the driving box (21).

2. The fan coil unit of an air conditioning system according to claim 1, characterized in that: A rubber sleeve is fixedly connected to the inner wall of the pipe insertion opening (4), and the rubber sleeve is mounted on the corresponding air inlet duct (10) and is slidably connected thereto.

3. The fan coil unit of an air conditioning system according to claim 1, characterized in that: A base plate (5) is fixedly connected at the rear end of the chassis (1) and between the two air outlets (3); four telescopic rods (6) distributed in a rectangular shape are fixedly connected to the rear end of the base plate (5); the telescopic ends of the four telescopic rods (6) are commonly fixedly connected to a mounting plate (7); springs (8) are sleeved on the four telescopic rods (6); the two ends of the springs (8) are respectively fixedly connected to the base plate (5) and the mounting plate (7); a double-headed motor (9) is fixedly mounted at the rear end of the mounting plate (7); the two output ends of the double-headed motor (9) are both coaxially fixedly connected to a driving rod (13); and the ends of the two driving rods (13) away from the double-headed motor (9) are respectively coaxially fixedly connected to two impellers (12).

4. The fan coil unit of an air conditioning system according to claim 3, characterized in that: The rear ends of the two bellows (11) are both fixedly connected to a rubber block, and the rear ends of the two rubber blocks are commonly fixedly connected to a fixing plate (14).

5. The fan coil unit of an air conditioning system according to claim 1, characterized in that: Two fixing blocks (15) are fixedly connected to both left and right ends of the chassis (1).

6. The fan coil unit of an air conditioning system according to claim 1, characterized in that: A sewage outlet (25) is provided on the inner bottom wall of the chassis (1) and on the left and right sides of the two middle support vertical blocks (17); a sewage collecting box (24) is fixedly connected to the lower end of the chassis (1); the two sewage outlets (25) are in communication with the sewage collecting box (24); the inner bottom wall of the sewage collecting box (24) is an inclined surface that slopes downward from left to right; and a drainage pipe (26) is in communication with the right end of the sewage collecting box (24).

7. The fan coil unit of an air conditioning system according to claim 1, characterized in that: Two push rods (27) are slidably attached to the inner bottom wall of the chassis (1) and are symmetrically distributed on the left and right sides. A limit slide bar (28) is fixedly connected between the left and right inner walls of the chassis (1) and at a front position. The upper ends of the two push rods (27) are fixedly connected to a first set block (29), and the first set block (29) is slidably sleeved on the limit slide bar (28). A door-shaped groove block (30) is fixedly connected between the left and right inner walls of the chassis (1) and at a rear position. A second bidirectional threaded rod (31) located in the door-shaped groove block (30) is rotatably connected inside the chassis (1). The upper ends of the two push rods (27) are fixedly connected to a second set block (32), and the two second sets (32) are threadedly sleeved on the second bidirectional threaded rod (31). A second motor (33) for driving the second bidirectional threaded rod (31) to rotate is fixedly installed at the left end of the chassis (1).

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