A test device for testing the thermal insulation performance of a wooden house

Abstract

The present application relates to the technical field of wood house production, in particular to a wood house heat preservation performance test equipment, which realizes fast and accurate alignment of wall surface temperature sensors outside the wood house and the center of a heat box, reduces the error of test results, and improves work efficiency; the equipment comprises a heat box, a heater, a mounting frame, two temperature sensors one, an isolation box and a temperature sensor two, a plurality of heaters are installed in the heat box, the two temperature sensors one are installed in the heat box through the mounting frame, and the temperature sensor two is installed in the middle of the isolation box; the equipment further comprises a ceramic head, two signal lines, a controller and a broken line detector, the ceramic head is installed on the mounting frame, the two signal lines are arranged horizontally and vertically, one end of each of the two signal lines is connected with the ceramic head, the other end of each of the two signal lines is connected with the controller, the controller is installed on the outer wall of the heat box, the broken line detector is installed on the front outer wall of the isolation box, and the probe of the broken line detector extends into the isolation box.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wood house production, and particularly relates to a wood house heat preservation performance test device. BACKGROUND

[0002] Before and after the construction of a wood house, the wood house needs to be tested for heat preservation performance to determine whether the heat preservation performance of the wood house meets the requirements, and the heat preservation performance of the wood house is inversely proportional to the heat transfer coefficient of the wall of the wood house, so the detection of the heat preservation performance of the wood house is the same as the method for detecting the heat transfer coefficient of the wall of the wood house, and the main methods for detection and test at present include the heat flow meter method, the temperature control box-heat flow meter method and the heat box method, wherein the test steps of the heat box method are as follows: 1, tightly abutting the open end of the heat box against the measured wood wall to achieve airtightness; 2, fixing the outdoor wall surface temperature sensor to be located at the center position relative to the heat box, closely abutting the wall surface, shielding the end of the sensor with tin paper to avoid direct sunlight, fixing the outdoor air sensor to be located at the center position relative to the heat box, being 10-10 cm away from the wall surface, and installing a radiation shield to avoid direct sunlight, and fixing the indoor air sensor to be located at the center of the measured room, being 1.5 m away from the ground; 3, turning on the heater in the heat box; 4, measuring the opening area of the heat box, recording the temperature data detected by the plurality of temperature sensors, and recording the test time, and calculating the heat transfer coefficient through a formula; however, it is found in actual operation that when adjusting the position of the temperature sensor outside the wood house, the relative distances from the indoor heat box to the ground and to the adjacent wall surface are generally measured, and the temperature sensor is installed at the measured position outside the wood house through the same measurement method, the cumulative deviation of this multiple measurement positioning method is large, the position of the wall surface temperature sensor outside the wood house cannot be well aligned with the center of the heat box, and the time consumption is long, resulting in large error of the test result and low work efficiency. SUMMARY

[0003] To solve the above technical problems, the present application provides a wood house heat preservation performance test device which can quickly and accurately align the wall surface temperature sensor outside the wood house with the center of the heat box, reduce the error of the test result, and improve the work efficiency.

[0004] The application discloses a wood house heat preservation performance test equipment, which comprises a hot box, a heater, a mounting frame, two temperature sensors one, an isolation box and a temperature sensor two, a heating chamber is arranged in the hot box, a port is arranged on the front end face of the hot box, the port is communicated with the heating chamber, a plurality of heaters are evenly arranged in the heating chamber of the hot box, the mounting frame is arranged in the heating chamber of the hot box, the two temperature sensors one are arranged on the mounting frame, a detection chamber is arranged in the isolation box, a rear port is arranged on the rear end face of the isolation box, the rear port is communicated with the detection chamber, and the temperature sensor two is arranged in the middle of the detection chamber of the isolation box.

[0005] Preferably, the wood house heat preservation performance test equipment further comprises a ceramic head, two signal lines, a controller and a broken line detector, the ceramic head is arranged on the mounting frame and located at the center of the heating chamber of the hot box, the two signal lines are arranged horizontally and vertically along the mounting frame, one end of each of the two signal lines is connected with the ceramic head, the other end of each of the two signal lines is connected with the controller, the controller is arranged on the outer wall of the hot box, the two temperature sensors one are electrically connected with the controller, the broken line detector is arranged on the front side outer wall of the isolation box, the probe of the broken line detector is arranged in the detection chamber of the isolation box and concentrically arranged with the temperature sensor two, an indoor air sensor is arranged in the middle of the wood house, the plurality of heaters are electrically connected with the controller, the port of the hot box is tightly closed on the inner wall of the wood house, the controller is used for supplying alternating current to the two signal lines, so that the alternating current forms two horizontal and vertical magnetic fields through the two signal lines, the ceramic head is located at the intersection of the two magnetic fields, the broken line detector is turned on, the isolation box is moved close to the wall surface outside the wood house, when the probe of the broken line detector finds one of the magnetic fields formed by the two signal lines, the broken line detector sends a signal, the isolation box is moved along the magnetic field according to the signal, when the probe of the broken line detector reaches the broken end of the signal line, the broken line detector sends another signal, and the position of the broken end of the signal line is marked, the position is the position of the ceramic head, the isolation box is fixed on the outer wall of the wood house, at this time, the temperature sensor two is aligned with the ceramic head, that is, the temperature sensor two is aligned with the center of the hot box, the plurality of heaters are turned on, the plurality of heaters heat the inner side of the wood wall in the port of the hot box, the two temperature sensors one detect the temperature in the heating chamber of the hot box, and the temperature sensor two detects the temperature of the outer wall of the wood house, the isolation box is shaded from sunlight, the temperature sensor of the wall surface outside the wood house is quickly and accurately aligned with the center of the hot box, the error of test results is reduced, and the working efficiency is improved.

[0005] Preferably, the wood house heat preservation performance test equipment further comprises a temperature sensor three and a sunshade, the temperature sensor three is arranged on the front side outer wall of the isolation box, the sunshade is arranged on the front side outer wall of the isolation box, and the sunshade covers the temperature sensor three; the temperature sensor three detects the air temperature outside the wood house, the sunshade covers the temperature sensor three, so that the temperature sensor three is prevented from being directly irradiated by sunlight, the air temperature inside and outside the wood house is detected in cooperation with the temperature sensor in the wood house, and the practicability of the equipment is improved.

[0006] Preferably, the device further comprises a sliding frame, a spring and a hook, the sliding frame is installed in the detection chamber of the isolation box, the temperature sensor two is slidingly installed in the middle of the sliding frame, the spring is sleeved on the outer end of the temperature sensor two, the two ends of the spring are connected with the sliding frame and the outer end of the temperature sensor two respectively, the outer end of the spring extends out of the rear port of the isolation box, the middle of the sliding frame is provided with the hook, and the hook hooks the outer end of the temperature sensor two; during the process of moving the isolation box to find the position of the ceramic head, the spring is compressed to make the sliding frame hook the temperature sensor two, so that the temperature sensor two is retracted into the detection chamber of the isolation box, and the temperature sensor two is prevented from colliding with the outer wall of the wooden house; after the position of the ceramic head is found, the hook is actuated to release the temperature sensor two, so that the temperature sensor two is in close contact with the wall of the wooden house, and the practicability of the device is improved.

[0007] Preferably, the device further comprises a cavity, the side wall of the heat box is provided with the cavity, and the cavity is filled with heat insulation material; by arranging the cavity and filling the cavity with heat insulation material, the heat insulation property of the side wall of the heat box is improved.

[0008] Preferably, the device further comprises a cover plate, a sealing rubber strip one and a sealing rubber strip two, the cover plate is installed on the side wall of the front port of the heat box, the cover plate closes the cavity, the sealing rubber strip one is installed on the cover plate and extends out of the side wall of the port of the heat box, and the sealing rubber strip two is installed on the side wall of the rear port of the isolation box; the cover plate closes the cavity, the heat insulation property of the side wall of the heat box is improved, the sealing rubber strip one and the sealing rubber strip two are installed to improve the sealing property between the port of the heat box and the inner wall of the wooden house, and the sealing property between the rear port of the isolation box and the outer wall of the wooden house is improved.

[0009] Preferably, the device further comprises an indicator light, the main body of the disconnection detector is provided with a display, a plurality of buttons and the indicator light; when the probe of the disconnection detector detects the magnetic field formed by the two signal lines, the indicator light is turned on, and when the probe of the disconnection detector is aligned with the ceramic head, the indicator light flashes, so that the ceramic head is positioned quickly and conveniently, and the practicability of the device is improved.

[0010] Preferably, the device further comprises a plurality of mounting plates, two sliding pipes and two supporting rods, a plurality of mounting plates are uniformly installed on the outer walls of the heat box and the isolation box, the mounting plates are respectively close to the port of the heat box and the rear port of the isolation box, mounting holes are arranged in the mounting plates, the two sliding pipes are vertically installed on the left and right outer walls of the heat box respectively, the upper portions of the two supporting rods are slidingly installed in the two sliding pipes respectively, positioning bolts are rotationally screwed on the outer walls of the two sliding pipes respectively, and the two positioning bolts press the two supporting rods in the two sliding pipes respectively; when the heat box is installed on the inner wall of the wooden house, the two supporting rods are elongated along the two sliding pipes, and the positioning bolts on the sliding pipes are tightened, so that the two supporting rods support the heat box to a certain height, and a plurality of wooden bolts are used to pass through the mounting holes of the mounting plates to fasten the heat box and the isolation box to the inner and outer walls of the wooden house, the installation operation is facilitated, and the practicability of the device is improved.

[0011] Preferably, the air charging pipe and the pressure gauge are also provided, the air charging pipe is installed on the outer wall of the heat box and communicates with the heating chamber of the heat box, the valve and the one-way valve are installed on the air charging pipe, the pressure gauge is installed on the outer wall of the heat box and the probe of the pressure gauge extends into the heating chamber of the heat box; after the heat box is installed on the inner wall of the wooden house, the air is charged to a certain pressure in the heating chamber of the heat box through the air charging pipe, the air pressure in the heating chamber of the heat box is known through the pressure gauge, the valve of the air charging pipe is closed after the air charging is stopped, the pressure retention in the heat box is known through the pressure gauge, the sealing between the heat box and the inner wall of the wooden house is tested, and the practicability of the equipment is improved.

[0012] Compared with the prior art, the beneficial effects of the present application are that: the indoor air sensor is installed in the middle of the wooden house, the plurality of heaters are electrically connected with the controller, the port of the heat box is tightly sealed against the inner wall of the wooden house, the controller is used for transmitting alternating current to the two signal lines, so that the alternating current forms two horizontal and vertical magnetic fields through the two signal lines, the ceramic head is located at the intersection of the two magnetic fields, the broken wire detector is turned on, the isolation box is moved close to the wall surface outside the wooden house, when the probe of the broken wire detector finds one of the magnetic fields formed by the two signal lines, the broken wire detector sends a signal, the isolation box is moved along the magnetic field according to the signal, when the probe of the broken wire detector reaches the broken end of the signal line, the broken wire detector sends another signal, the position of the broken end of the signal line is marked, the position is the ceramic head, the isolation box is fixed on the outer wall of the wooden house, at this time, the temperature sensor two is aligned with the ceramic head, that is, the temperature sensor two is aligned with the center of the heat box, the plurality of heaters are turned on, the plurality of heaters heat the inner side of the wooden wall in the port of the heat box, the two temperature sensors one detect the temperature in the heating chamber of the heat box, the temperature sensor two detects the temperature of the outer wall of the wooden house, the isolation box blocks the sunlight and the like, the temperature sensor of the wall surface outside the wooden house is quickly and accurately aligned with the center of the heat box, the error of the test result is reduced, and the work efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] Fig. 1 is a structural schematic diagram of the present application;

[0014] Fig. 2 is an isometric structural schematic diagram of the present application;

[0015] Fig. 3 is an exploded enlarged structural schematic diagram of the isolation box, the temperature sensor two and the broken wire detector and the like structures;

[0016] Fig. 4 is a mounting frame; 4, an enlarged structural schematic diagram of the temperature sensor one, the ceramic head, the signal line and the controller and the like structures;

[0017] Marked in the drawing: 1, hot box; 2, heater; 3, mounting frame; 4, temperature sensor one; 5, isolation box; 6, temperature sensor two; 7, ceramic head; 8, signal line; 9, controller; 10, broken line detector; 11, temperature sensor three; 12, sunshade cover; 13, slide frame; 14, spring; 15, hook; 16, cavity; 17, cover plate; 18, sealing rubber strip one; 19, sealing rubber strip two; 20, indicator light; 21, mounting plate; 22, slide pipe; 23, support rod; 24, inflation pipe; 25, pressure gauge. DETAILED DESCRIPTION

[0018] For the purpose of facilitating the understanding of the present application, a more complete understanding of the present application will be provided in the following with reference to the relevant drawings. The present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0019] EMBODIMENT

[0020] The utility model provides a kind of wood house thermal insulation performance test equipment, including hot box 1, heater 2, mounting frame 3, two temperature sensors one 4, isolation box 5 and temperature sensor two 6, the inside of hot box 1 is provided with heating chamber, the front end surface of hot box 1 is provided with port, and port is communicated with heating chamber, multiple heaters 2 are evenly installed in the heating chamber of hot box 1, mounting frame 3 is installed in the heating chamber of hot box 1, two temperature sensors one 4 are installed on mounting frame 3, the inside of isolation box 5 is provided with detection chamber, the rear end surface of isolation box 5 is provided with rear port, and rear port is communicated with detection chamber, temperature sensor two 6 is installed in the middle part of the detection chamber of isolation box 5;Still including ceramic head 7, two signal lines 8, controller 9 and broken line detector 10, ceramic head 7 is installed on mounting frame 3, and ceramic head 7 is located in the center of the heating chamber of hot box 1, two signal lines 8 are respectively arranged horizontally and vertically along mounting frame 3, one end of two signal lines 8 is connected with ceramic head 7, the other end of two signal lines 8 is connected with controller 9, controller 9 is installed on the outer wall of hot box 1, two temperature sensors one 4 are electrically connected with controller 9, broken line detector 10 is installed on the front side outer wall of isolation box 5, the probe of broken line detector 10 is inserted into the detection chamber of isolation box 5, and the probe of broken line detector 10 is concentrically arranged with temperature sensor two 6;Still including slide 13, spring 14 and hook 15, slide 13 is installed in the detection chamber of isolation box 5, temperature sensor two 6 is slidingly installed in the middle part of slide 13, spring 14 is sleeved on the outer end of temperature sensor two 6, the two ends of spring 14 are connected with the outer end of slide 13 and temperature sensor two 6 respectively, the outer end of spring 14 is stretched outside the rear port of isolation box 5, the middle part of slide 13 is provided with hook 15, and the hook of hook 15 hooks the outer end of temperature sensor two 6;Still including indicating lamp 20, display, multiple buttons and indicating lamp 20 are provided on the main body of broken line detector 10.At the start of the test, an indoor air sensor is installed in the middle of the cabin. Multiple heaters 2 are electrically connected to the controller 9. The port of the heating box 1 is sealed tightly against the inner wall of the cabin. The controller 9 supplies alternating current to two signal lines 8, causing the alternating current to form two magnetic fields, one horizontal and one vertical. The ceramic head 7 is located at the intersection of the two magnetic fields, i.e., the broken ends of the two signal lines 8. The broken wire detector 10 is activated, and the compression spring 14 causes the slide 13 to hook the second temperature sensor 6, causing the second temperature sensor 6 to retract into the detection chamber of the isolation box 5. The isolation box 5 is moved close to the wall outside the cabin. When the indicator light 20 lights up, the probe of the broken wire detector 10 finds the two signal lines 8 forming a magnetic field. One of the two magnetic fields is used. Following the indication of indicator light 20, the isolation box 5 is moved horizontally or vertically along the magnetic field. When indicator light 20 flashes, the break in signal line 8, i.e., the ceramic head 7, is located. The isolation box 5 is then fixed to the outer wall of the wooden house. At this point, temperature sensor 6 is aligned with ceramic head 7, meaning temperature sensor 6 is aligned with the center of the heating chamber 1. Multiple heaters 2 are activated, heating the inner side of the wooden wall inside the port of the heating chamber 1. Two temperature sensors 4 detect the temperature inside the heating chamber of the heating chamber 1, and temperature sensor 6 detects the temperature of the outer wall of the wooden house. The isolation box 5 blocks sunlight, achieving rapid and accurate alignment of the temperature sensors on the outer wall of the wooden house with the center of the heating chamber.

[0021] like Figs. 1 to 4 As shown, the wooden house insulation performance testing device of the present invention, when in operation, firstly extends two support rods 23 along two sliding pipes 22 and tightens the positioning bolts on the sliding pipes 22, so that the two support rods 23 support the heat box 1 to a certain height. Multiple wooden bolts are used to pass through the mounting holes of multiple mounting plates 21 to secure the heat box 1 to the inner and outer walls of the wooden house. Then, the controller 9 transmits alternating current to two signal lines 8, so that the alternating current forms two magnetic fields, one horizontal and one vertical, through the two signal lines 8. The ceramic head 7 is located at the intersection of the two magnetic fields. Then, the wire break detector 10 is activated, so that the probe of the wire break detector 10 finds the two signal lines 8 forming two magnetic fields and the indicator light 20 lights up. Outside the wooden house, near the wall, the isolation box 5 moves along the two magnetic fields to find the two magnetic fields. At the intersection of the ceramic head 7, hook 15 is moved to release temperature sensor 6, making it in close contact with the wall of the wooden house. The isolation box 5 is fixed to the outer wall of the wooden house by multiple mounting plates 21. At this time, temperature sensor 6 is aligned with ceramic head 7, that is, temperature sensor 6 is aligned with the center of the heat box 1. Multiple heaters 2 are turned on, and multiple heaters 2 heat the inner side of the wooden wall inside the port of the heat box 1. Two temperature sensors 4 detect the temperature in the heating chamber of the heat box 1, and temperature sensor 6 detects the temperature of the outer wall of the wooden house. The isolation box 5 blocks sunlight, etc. Finally, the temperature information detected by two temperature sensors 4, temperature sensor 6, and temperature sensor 11 is recorded. These temperature information can be input into the calculation formula.

[0022] The main function realized by the application is to realize the fast and accurate alignment of the wall surface temperature sensor outside the wooden house and the center of the heat box, reduce the error of test results, and improve work efficiency.

[0023] The installation mode, connection mode or setting mode of the wood house heat preservation performance test equipment are all common mechanical modes, and as long as the beneficial effects can be achieved, they can be implemented; the temperature sensor 4, the temperature sensor 6, the broken line detector 10, the ceramic head 7, the heater 2, the inflation pipe 24, the pressure gauge 25, the controller 9, the signal line 8, the indicator light 20, the sealing rubber strip 18, the sealing rubber strip 19, the temperature sensor 11 and the spring 14 of the wood house heat preservation performance test equipment are purchased on the market, and the technical personnel in the industry only need to install and operate according to the attached instruction manual, without the technical personnel in the field having to pay creative labor.

[0024] All the technical and scientific terms used herein have the same meaning as that generally understood by the technical personnel belonging to the technical field of the application. The terms used in the specification of the application herein are only for the purpose of describing the specific embodiments, and are not intended to limit the application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0025] The above is only the preferred embodiment of the application, and it should be pointed out that for ordinary technical personnel in the art, several improvements and modifications can be made without departing from the technical principles of the application, and these improvements and modifications should be regarded as the protection scope of the application.

Claims

1. A wood house thermal insulation performance test equipment, comprising a hot box (1), a heater (2), a mounting frame (3), two temperature sensor one (4), an isolation box (5) and a temperature sensor two (6), the inside of the hot box (1) is provided with a heating chamber, the front end face of the hot box (1) is provided with a port, the port is communicated with the heating chamber, a plurality of heaters (2) are uniformly installed in the heating chamber of the hot box (1), the mounting frame (3) is installed in the heating chamber of the hot box (1), two temperature sensor one (4) are installed on the mounting frame (3), the inside of the isolation box (5) is provided with a detection chamber, the rear end face of the isolation box (5) is provided with a rear port, the rear port is communicated with the detection chamber, the temperature sensor two (6) is installed in the middle part of the detection chamber of the isolation box (5); characterized in that, The ceramic head (7), two signal lines (8), the controller (9) and the broken line detector (10) are further included, the ceramic head (7) is installed on the mounting frame (3), the ceramic head (7) is located at the center of the heating cavity of the heat box (1), the two signal lines (8) are arranged horizontally and vertically along the mounting frame (3) respectively, one end of the two signal lines (8) is connected with the ceramic head (7), the other end of the two signal lines (8) is connected with the controller (9), the controller (9) is installed on the outer wall of the heat box (1), the two temperature sensors one (4) are electrically connected with the controller (9), the broken line detector (10) is installed on the front side outer wall of the isolation box (5), the probe of the broken line detector (10) extends into the detection chamber of the isolation box (5), and the probe of the broken line detector (10) is arranged concentrically with the temperature sensor two (6).

2. The wood house thermal insulation performance test apparatus according to claim 1, wherein The temperature sensor three (11) and the sunshade cover (12) are further included, the temperature sensor three (11) is installed on the front side outer wall of the isolation box (5), and the sunshade cover (12) is installed on the front side outer wall of the isolation box (5), wherein the sunshade cover (12) covers the temperature sensor three (11).

3. The wood house thermal insulation performance test apparatus according to claim 1, wherein The slide frame (13), the spring (14) and the hook (15) are further included, the slide frame (13) is installed in the detection chamber of the isolation box (5), the temperature sensor two (6) is slidingly installed at the middle portion of the slide frame (13), the spring (14) is sleeved on the outer end of the temperature sensor two (6), the two ends of the spring (14) are connected with the slide frame (13) and the outer end of the temperature sensor two (6) respectively, the outer end of the spring (14) extends out of the rear end of the isolation box (5), the middle portion of the slide frame (13) is provided with the hook (15), and the hook (15) hooks the outer end of the temperature sensor two (6).

4. The wood house thermal insulation performance test apparatus according to claim 1, wherein The cavity (16) is further included, the cavity (16) is arranged in the side wall of the heat box (1), and the cavity (16) is filled with a heat insulation material.

5. The wood house thermal insulation performance test apparatus according to claim 4, wherein The cover plate (17), the sealing rubber strip one (18) and the sealing rubber strip two (19) are further included, the cover plate (17) is installed on the front end side wall of the heat box (1), the cover plate (17) closes the cavity (16), the sealing rubber strip one (18) is installed on the cover plate (17) and extends out of the side wall of the port of the heat box (1), and the sealing rubber strip two (19) is installed on the rear end side wall of the isolation box (5).

6. The wood house thermal insulation performance test apparatus according to claim 1, wherein The indicator light (20) is further included, and the main body of the broken line detector (10) is provided with a display, a plurality of buttons and the indicator light (20).

7. The wood house thermal insulation performance test apparatus according to claim 1, wherein The heat box (1) and the isolation box (5) are uniformly provided with a plurality of mounting plates (21) on the outer walls, the mounting plates (21) are respectively close to the port of the heat box (1) and the rear port of the isolation box (5), the mounting plates (21) are uniformly provided with mounting holes, two slide pipes (22) are vertically installed on the outer walls of the left and right sides of the heat box (1), the upper parts of two supporting rods (23) are slidably installed in the two slide pipes (22), the outer walls of the two slide pipes (22) are rotatably screwed with positioning bolts, and the two positioning bolts press the two supporting rods (23) in the two slide pipes (22) respectively.

8. The wood house thermal insulation performance test apparatus according to claim 1, wherein The heat box (1) and the isolation box (5) are uniformly provided with a plurality of mounting plates (21) on the outer walls, the mounting plates (21) are respectively close to the port of the heat box (1) and the rear port of the isolation box (5), the mounting plates (21) are uniformly provided with mounting holes, two slide pipes (22) are vertically installed on the outer walls of the left and right sides of the heat box (1), the upper parts of two supporting rods (23) are slidably installed in the two slide pipes (22), the outer walls of the two slide pipes (22) are rotatably screwed with positioning bolts, and the two positioning bolts press the two supporting rods (23) in the two slide pipes (22) respectively. The heat box (1) and the isolation box (5) are uniformly provided with a plurality of mounting plates (21) on the outer walls, the mounting plates (21) are respectively close to the port of the heat box (1) and the rear port of the isolation box (5), the mounting plates (21) are uniformly provided with mounting holes, two slide pipes (22) are vertically installed on the outer walls of the left and right sides of the heat box (1), the upper parts of two supporting rods (23) are slidably installed in the two slide pipes (22), the outer walls of the two slide pipes (22) are rotatably screwed with positioning bolts, and the two positioning bolts press the two supporting rods (23) in the two slide pipes (22) respectively.

Images