CN110145045A - A position-limiting energy-dissipating structure and its construction method - Google Patents

Abstract

The invention discloses a position-limiting energy-dissipating structure and a construction method thereof. A plurality of energy-dissipating sheets uniformly distributed in ring cavities of the inner cylinder and the outer cylinder are arranged between the inner cylinder and the outer cylinder of the position-limiting energy-dissipating structure. The outer cylinder is fixed on the crossbeam through the first connecting steel plate. Two limiting plates are welded on the outer wall of the outer cylinder, and each of the two limiting plates is provided with two limiting holes. The two limiting holes are located on the axis of the outer cylinder. The inner cylinder is fixed on the column through the second connecting steel plate; the drive chain includes three sections of the first chain and two sections of the second chain, and the limit hole is that the first chain cannot pass through but the second chain can pass through hole; two sections of the second chain respectively pass through a limit hole of two limit plates, and the construction method of the limit energy dissipation structure of the present invention uses a limit adjustment ruler to install the drive chain. The invention can increase the stability of the structure, improve the anti-deformation ability of the structure, and reduce the damage to the structure caused by earthquakes. The construction method of the invention can accurately control the installation position of the driving chain.

Description

A position-limiting energy-dissipating structure and its construction method

technical field

The invention relates to the field of building anti-seismic technology, in particular to a position-limiting energy-dissipating structure and a construction method thereof.

Background technique

my country is an earthquake-prone country, especially in recent years, coupled with human activities, making my country's earthquakes more frequent. Therefore, the damage of structures in earthquakes is also more and more serious. The occurrence of earthquakes cannot be controlled by people, so how to reduce the damage of structures in earthquakes is particularly important. The energy generated during the earthquake is not released all at once, but will be released one after another. Therefore, the damage to the structure caused by the earthquake is continuous, and the connection between ordinary structures may only resist the energy released by an earthquake, but cannot withstand the residual energy of the earthquake. Therefore, it is particularly important to improve the connection mode between structures so that they can continuously resist the energy released by earthquakes.

Contents of the invention

The technical problem to be solved by the present invention is: the present invention provides a position-limiting energy-dissipating structure with good seismic performance, and the present invention also provides a construction method of the above-mentioned position-limiting energy-dissipating structure.

In order to solve the above-mentioned technical problems, the position-limiting energy-dissipating structure of the present invention includes a column and a beam, and a position-limiting energy-dissipating device is provided at the angle between the column and the beam. The position-limiting energy-dissipating device includes a roller and a drive chain, and A fixed pulley is set above the drum, and a fixed shaft is fixed on the beam. The fixed shaft and the column are located on both sides of the drum. The fixed shaft is covered with a torsion spring. A plurality of energy dissipation sheets uniformly distributed in the ring cavity of the inner cylinder and the outer cylinder are arranged between the outer cylinder, one end of the energy dissipation sheet is welded to the outer wall of the inner cylinder, and the other end is welded to the inner wall of the outer cylinder, the energy dissipation sheet The middle of the outer cylinder is narrower than the two ends; the outer cylinder is fixed on the beam through the first connecting steel plate, and two limiting plates are welded on the outer wall of the outer cylinder. The angle between the two limiting plates is 90 degrees, and one of the limiting plates It is welded horizontally on the side of the outer cylinder away from the column, and the other limit plate is welded vertically on the outer cylinder on the side away from the beam. The two limit plates are each provided with two limit holes, and the two limit holes are in the outer cylinder. The axis of the hole is arranged in the direction of the axis, the axis of the limit hole is perpendicular to the axis of the outer cylinder, and the inner cylinder is fixed on the column through the second connecting steel plate; the drive chain includes three sections of the first chain and two sections of the second chain, three sections The first chain and the two second chains are connected into a line segment chain, all the first chains are spaced apart, and all the second chains are spaced apart, and the limiting hole is a hole through which the first chain cannot pass but the second chain can pass; the first The end point of the first chain of the section is welded on the beam, and the two sections of the second chain pass through a limit hole of the two limit plates respectively, the first chain of the second section is hung on the fixed pulley, and the two ends of the torsion spring are respectively connected with the The shaft is fixedly connected to the end of the first chain of the third section. When the column and the crossbeam are in the natural state, the driving chain is in the fully extended state, and the torsion spring is in the natural state.

In order to protect the drum, the distance between the end of the third section of the first chain away from the fixed shaft and the end of the second section of the first chain away from the fixed shaft from the nearest limit plate is equal, and the aforementioned distance is 2-5mm. By setting the distance between the drive chain and the limit plate, the roller starts to consume energy only when the beam and column are deformed to a certain extent, which can protect the energy consumption function of the roller as much as possible.

In order to facilitate the installation of the inner cylinder, a rotating groove is provided on the outer cylinder. When the column and the beam are in a natural state, the second connecting steel plate is located in the middle of the rotating groove. When the outer cylinder rotates relative to the inner cylinder, there is a second connection in the rotating groove. The activity space of the steel plate.

In order to facilitate the rotation of the outer cylinder, the first connecting steel plate and the second connecting steel plate are made of mild steel.

In order to facilitate the maintenance of the energy-limiting device, the outer side of the fixed pulley is covered with a fixed box, and the fixed box is fixed on the column through embedded bolts; the outer side of the fixed shaft is covered with a movable box, and the movable box is fixed on the beam through embedded bolts.

In order to reduce the friction between the drive chain and the outer wall of the outer cylinder, a sliding limit guide rail is welded between the two limit plates on the outer cylinder, and the two second chains are slidably connected with the sliding limit guide rail.

The construction method of the position-limiting energy-dissipating structure of the present invention comprises the following steps:

(1) Install the roller, weld the roller welded with two limit plates, the first connecting steel plate and the second connecting steel plate to the angle between the beam and the column, install the fixed pulley and the fixed box on the column, and fix the shaft And the activity box is installed on the beam;

(2) Use the limit adjustment ruler to install the drive chain. The initial length of the first chain in the first section and the initial length of the first chain in the third section are both longer than the actual required length. The other chains are the set lengths, and the limit adjustment The ruler includes a clamp and an adjustment plate. The clamp is C-shaped. The clamp includes two first horizontal plates and side plates. The two first horizontal plates are parallel to each other. A horizontal plate and a side plate are respectively provided with bolt holes, the adjustment plate is an L-shaped plate, the adjustment plate includes a vertical plate and a second horizontal plate, a long hole is opened on the vertical plate, and a U-shaped adjustment plate is opened on the second horizontal plate The U-shaped adjusting groove is a groove through which the first chain cannot pass but the second chain can pass. The long holes on the vertical plate and the bolt holes on the side plates are connected by adjusting bolts. The connected positioning pin and the vertical plate of the adjustment plate are provided with a scale; pass the second chain through the sliding limit guide rail and the two limit holes on the two limit plates respectively, and hang the second section of the first chain on the fixed plate. On the pulley, put the torsion spring on the fixed shaft, weld one end of the torsion spring to the fixed shaft; insert the clamp into the limit plate parallel to the beam, the limit plate is located between the two first horizontal plates, and lock it Bolt, screw the locking bolt into the bolt hole on the first horizontal plate to fix the fixture on the limit plate parallel to the beam, loosen the adjusting bolt to make the vertical plate active, adjust the positioning pin to the level, adjust the vertical plate position so that the distance from the bottom of the second cross plate to the bottom of the limit plate parallel to the cross beam reaches the set distance, tighten the adjusting bolt, and push the second chain under the limit plate parallel to the cross beam into the U-shaped adjustment groove, Pull the head end of the first chain of the first section until the first chain of the third section is on the U-shaped adjustment groove, and until the drive chain cannot be pulled, connect the end of the first chain of the third section away from the second chain to the torsion spring. Weld the other end so that the first chain of the third section is in a fully extended state, and the torsion spring is in a natural state. Weld the end of the first chain away from the second chain to the crossbeam so that the drive chain is in a fully extended state. Remove the redundant part of the first chain of the third section and the first section of the first chain, loosen the locking bolt on the first horizontal plate, and remove the limit adjustment ruler from the limit plate.

The beneficial effects of the present invention are: the position-limiting energy-dissipating structure of the present invention can not only consume the energy released by an earthquake well, but also continuously absorb the residual energy of the earthquake, reduce the damage to beams and columns caused by earthquakes, and increase the energy efficiency of beams and columns. Stability, improving the anti-deformation ability of beams and columns; the invention uses a specially designed limit adjustment ruler to install the drive chain, which can accurately control the distance from the second chain end point to the limit plate; the invention has simple structure, convenient construction, and cost-effective high.

Description of drawings

Fig. 1 is a structural schematic diagram of a position-limiting energy-dissipating structure in Embodiment 1 of the present invention;

Figure 2 is an enlarged schematic view of the drum of Embodiment 1 of the present invention;

Fig. 3 is an enlarged schematic diagram of the structure of the sliding chute according to Embodiment 1 of the present invention;

Figure 4 is an enlarged schematic view of the structure at both ends of the torsion spring in Embodiment 1 of the present invention

Fig. 5 is a schematic diagram of the front view structure of the limit adjustment ruler according to Embodiment 1 of the present invention;

Fig. 6 is an enlarged schematic view of the structure of the vertical plate on the limit adjustment plate according to Embodiment 1 of the present invention;

Fig. 7 is an enlarged schematic diagram of the structure of the second horizontal plate on the limit adjustment plate according to the first embodiment of the present invention;

Figure 8 is an enlarged schematic view of the drum in Embodiment 2 of the present invention;

1-column; 2-beam; 3-roller; 4-drive chain; 5-first chain; 6-second chain; 7-second connecting steel plate; 8-first connecting steel plate; 9-energy dissipation sheet; 10 -outer cylinder; 11-inner cylinder; 12-limit plate; 13-sliding limit guide rail; 14-fixed pulley; 15-fixed box; 16-fixed shaft; 17-movable box; 18-limit hole; 19- Rotation slot; 20-torsion spring; 21-fixture; 22-adjusting plate; 23-first horizontal plate; 24-side plate; 25-second horizontal plate; 26-vertical plate; 27-long hole; 28-scale ; 29-location needle; 30-U-shaped adjustment hole.

Detailed ways

Embodiment one

As shown in Figure 1, a position-limiting energy-dissipating structure includes a column 1 and a beam 2, and a position-limiting energy-dissipating device is provided at the angle between the column 1 and the beam 2, and the position-limiting energy-dissipating device includes a roller 3 and a drive chain 4. A fixed pulley 14 is provided on the column 1 higher than the drum, and the outer side of the fixed pulley 14 is covered with a fixed box 15. The fixed box 15 is fixed on the column 1 by embedded bolts; Axle 16 and column 1 are located on both sides of the drum, fixed axis 16 is covered with torsion spring 20, and the outer side of said fixed axis 16 is covered with movable box 17, and movable box 17 is fixed on the crossbeam 2 by embedded bolts.

The drum includes an inner cylinder 11 and an outer cylinder 10. Between the inner cylinder 11 and the outer cylinder 10, a plurality of energy-dissipating sheets 9 are uniformly distributed in the ring cavity of the inner cylinder and the outer cylinder. The outer wall of the outer cylinder is welded, and the other end is welded with the inner wall of the outer cylinder 10. The middle of the energy dissipation sheet 9 is narrower than the two ends; the outer cylinder 10 is fixed on the beam 2 through the first connecting steel plate 8, and two Limiting plate 12, the angle between the two limiting plates 12 is 90 degrees, one of the limiting plates 12 is welded horizontally on the side of the outer cylinder 10 away from the column 1, and the other limiting plate 12 is welded vertically on the side of the outer cylinder 10 away from the column 1. On one side of the crossbeam 2, the two limiting plates 12 are respectively provided with two limiting holes 18, the axes of the limiting holes 18 are all perpendicular to the axis of the outer cylinder 10, and the two limiting holes 12 on each limiting plate 12 The holes 18 are arranged in the radial direction of the outer cylinder 10, and the outer cylinder 10 is welded with a sliding limit guide rail 13 between the two limit plates 12, and the two second chains 6 are slidably connected with the sliding limit guide rail 13, as As shown in Figure 2; the inner cylinder 11 is fixed on the column 1 through the second connecting steel plate 7; the first connecting steel plate and the second connecting steel plate are made of mild steel; as shown in Figure 3, the outer cylinder 10 is provided with a rotating groove 19, When the column 1 and the beam 2 are in the natural state, the second connecting steel plate 7 is located in the middle of the rotating groove 19, and when the inner cylinder 11 and the outer cylinder 10 rotate, there is room for the second connecting steel plate 7 to move in the rotating groove 19.

As shown in Figure 1, the drive chain 4 includes three sections of the first chain 5 and two sections of the second chain 6, the three sections of the first chain 5 and the two sections of the second chain 6 are connected into a line chain, and all the first chains 5 are in phase interval, all the second chains 6 are spaced apart, and the limit hole 18 is a hole through which the first chain 5 cannot pass but the second chain 6 can pass; the end points of the first chain 5 of the first section are welded on the beam 2, the first section of the first chain The second chain 6 passes through the limit hole 18 away from the drum on the two limit plates 12, the first chain 5 of the second section is hung on the fixed pulley 14, and the second chain 6 of the second section passes through the two limit plates 12 The limit hole 18 close to the drum; as shown in Figure 4, the two ends of the torsion spring 20 are fixedly connected with the fixed shaft 16 and the end of the first chain 5 of the third section respectively, when the column 1 and the beam 2 are in the natural state, the drive The chain 4 is in a fully extended state, and the torsion spring 20 is in a natural state.

The distance between the end of the third segment of the first chain 5 away from the fixed shaft 16 and the end of the second segment of the first chain 5 far away from the fixed shaft 16 is equal to the distance from the nearest limit plate 12, and the aforementioned distance is 2-5 mm.

The natural state of the column and the beam refers to the state when the column 1 and the beam 2 do not undergo structural deformation.

The fully elongated state of the drive chain means that the drive chain 4 is in a stretched state without slack.

The natural state of the torsion spring means that both ends of the torsion spring 20 are not subjected to tension.

In order to understand the use of the limit energy dissipation structure more clearly, the present invention provides the construction method of the limit energy dissipation structure, the main special feature is to use the limit adjustment ruler to determine the actual required length of the drive chain 4 and determine the column 1 and the crossbeam 2 are in the natural state, the distance between the connecting ends of the first chain 5 and the second chain 6 and the limit plate 12 specifically includes the following steps:

(1) Install the roller, weld the roller welded with two limit plates 12, the first connecting steel plate 8, and the second connecting steel plate 7 to the angle between the beam 2 and the column 1, and install the fixed pulley 14 and the fixed box 15 On the column 1, the fixed shaft 16 and the movable box 17 are installed on the beam 2;

(2) Use the limit adjustment ruler to install the drive chain 4. The initial length of the drive chain 4 is longer than the actual required length, and the other chains are the set lengths; as shown in Figure 5, the limit adjustment ruler includes a clamp 21 and an adjustment plate 22. The clamp 21 is C-shaped. The clamp includes two first horizontal plates 23 and side plates 24. The two first horizontal plates 23 are parallel to each other. One of the first horizontal plates 23 and the side plates 24 has bolt holes respectively. The adjustment plate 22 is an L-shaped plate, and the adjustment plate includes a vertical plate 26 and a second horizontal plate 25. As shown in Figure 6, the vertical plate 26 is provided with a strip hole 27, as shown in Figure 7, the second horizontal plate 25 There is a U-shaped adjustment groove 30 on the top, and the U-shaped adjustment groove 30 is a groove through which the first chain 5 cannot pass but the second chain 6 can pass. The vertical plate 26 and the side plate 24 are connected by adjusting bolts, and the adjusting bolts pass through the vertical The strip hole 27 on the plate 26 and the bolt hole on the side plate 24 are provided with a positioning pin 29 that is rotatably connected with the adjusting bolt, and a scale 28 is provided on the vertical plate 26 of the adjusting plate 22; the second chain 6 Respectively pass through the two limit holes 18 on the sliding limit guide rail 13 and the two limit plates 12, hang the second section of the first chain 5 on the fixed pulley 14, put the torsion spring 20 on the fixed shaft 16, Weld one end of the torsion spring 20 on the fixed shaft 16; insert the fixture into the limit plate 12 parallel to the beam, the limit plate 12 is between the two first transverse plates 23, take the locking bolt, and put the locking bolt Screw it into the bolt hole on the first horizontal plate 23, fix the fixture on the limit plate 12 parallel to the cross beam, loosen the adjusting bolts to make the vertical plate 26 in an active state, adjust the positioning pin 29 to the level, and move the vertical plate 26 Make the distance between the bottom surface of the second cross plate 25 and the bottom surface of the limit plate 12 parallel to the cross beam reach the set distance, tighten the adjusting bolt, and push the second chain 6 under the limit plate 12 parallel to the cross beam to the U-shaped adjustment In the slot 30, pull the head end of the first chain 5 of the first section until the first chain 5 of the third section is pushed against the bottom surface of the U-shaped adjustment groove 30, until the driving chain 4 cannot be pulled, the first chain 5 of the third section One end away from the second chain 6 is welded to the other end of the torsion spring 20, so that the third section of the first chain 5 is in a fully extended state, the torsion spring 20 is in a natural state, and the first section of the first chain 5 is kept away from the second chain 6 One end of one end is welded to the beam 2, so that the driving chain 4 is in a fully extended state, and this fully extended state does not include the redundant driving chain 4, and the first section of the first chain 5 and the third section of the first chain 5 are cut off. , Loosen the locking bolts on the first cross plate 23, and remove the limit adjustment ruler from the limit plate 12 parallel to the cross beam.

Embodiment two

As shown in Figure 8, the difference between this embodiment and the first embodiment is that two limiting plates 12 are welded on the outer wall of the outer cylinder 10, and the angle between the two limiting plates 12 is 90 degrees, and one of the limiting plates 12 The position plate 12 is welded horizontally on the side of the outer cylinder 10 away from the column 1, and the other limit plate 12 is welded vertically on the side of the outer cylinder 10 away from the beam 2, and each of the two limit plates 12 is provided with two limit holes 18. Two limit holes 18 are arranged in the axial direction of the outer cylinder 10, the axes of the limit holes 18 are parallel to the axis of the outer cylinder 10, and two sections of the second chain 6 respectively pass through one limit hole of the two limit plates 12 .

The sliding limit guide rail 13 in the foregoing embodiments can be a cage with multiple layers of balls or rollers, the cage is fixed on the outer cylinder 10, and the second chain 6 passes through the middle of the two layers of balls or rollers.

The working principle of the position-limiting energy-dissipating structure of the present invention: the position-limiting energy-dissipating device of the present invention is arranged at the angle between the two sides of the column 1 and the beam 2 . When an earthquake occurs, when the angle between the column 1 and the crossbeam 2 becomes large, the torsion spring 20 is stretched, the drive chain 4 becomes longer, the fixed pulley 14 impels the drive chain 4 to rotate, and the first chain 5 of the drive chain 4 is connected to the second chain 4. The connecting end of the chain 6 keeps approaching the limit plate 12, and when it reaches the limit plate 12, since the first chain 5 cannot pass through the limit hole 18, the driving chain 4 pulls the limit plate 12, and drives the outer cylinder through the limit plate 12 10 rotation, because the inner cylinder 11 is fixed on the column 1 through the second connecting steel plate 7, relative rotation occurs between the outer cylinder 10 and the inner cylinder 11, and the energy dissipation sheet 9 between the outer cylinder 10 and the inner cylinder 11 breaks, so the energy consumption The energy sheet 9 absorbs and consumes the energy released by the earthquake. When the outer cylinder 10 rotates in a large range, the first connecting steel plate 8 and the second connecting steel plate 7 deform or even break, further absorbing and consuming the energy released by the earthquake. After the earthquake, the damaged energy-limiting device can be disassembled at the joint, and a new energy-limiting device can be installed.

Claims (7)

1. A position-limiting energy-dissipating structure, comprising a column and a beam, and a position-limiting energy-dissipating device is arranged at the angle between the column and the beam, characterized in that: the position-limiting energy-dissipating device includes a roller and a drive chain, and A fixed pulley is set above the drum, and a fixed shaft is fixed on the beam. The fixed shaft and the column are located on both sides of the drum. The fixed shaft is covered with a torsion spring. A plurality of energy dissipation sheets uniformly distributed in the ring cavity of the inner cylinder and the outer cylinder are arranged between the outer cylinder, one end of the energy dissipation sheet is welded to the outer wall of the inner cylinder, and the other end is welded to the inner wall of the outer cylinder, the energy dissipation sheet The middle of the outer cylinder is narrower than the two ends; the outer cylinder is fixed on the beam through the first connecting steel plate, and two limiting plates are welded on the outer wall of the outer cylinder. The angle between the two limiting plates is 90 degrees, and one of the limiting plates It is welded horizontally on the side of the outer cylinder away from the column, and the other limit plate is welded vertically on the outer cylinder on the side away from the beam. The two limit plates are each provided with two limit holes, and the two limit holes are in the outer cylinder. The axis of the hole is arranged in the direction of the axis, the axis of the limit hole is perpendicular to the axis of the outer cylinder, and the inner cylinder is fixed on the column through the second connecting steel plate; the drive chain includes three sections of the first chain and two sections of the second chain, three sections The first chain and the two second chains are connected into a line segment chain, all the first chains are spaced apart, and all the second chains are spaced apart, and the limiting hole is a hole through which the first chain cannot pass but the second chain can pass; the first The end point of the first chain of the section is welded on the beam, and the two sections of the second chain pass through a limit hole of the two limit plates respectively, the first chain of the second section is hung on the fixed pulley, and the two ends of the torsion spring are respectively connected with the The shaft is fixedly connected to the end of the first chain of the third section. When the column and the crossbeam are in the natural state, the driving chain is in the fully extended state, and the torsion spring is in the natural state. 2. The position-limiting energy-dissipating structure according to claim 1, characterized in that: the end of the third section of the first chain away from the fixed shaft and the end of the second section of the first chain far away from the fixed shaft are connected to the nearest The distance between the limiting plates is equal, and the aforementioned distance is 2-5mm. 3. The position-limiting energy-dissipating structure according to claim 2, characterized in that: the outer cylinder is provided with a rotating groove, when the upright column and the beam are in a natural state, the second connecting steel plate is located in the middle of the rotating groove, when When the inner cylinder and the outer cylinder rotate relatively, there is a movable space for the second connecting steel plate in the rotation groove. 4. The position-limiting energy-dissipating structure according to claim 3, wherein the first connecting steel plate and the second connecting steel plate are made of mild steel. 5. The position-limiting energy-dissipating structure according to claim 4, characterized in that: the outer side of the fixed pulley is covered with a fixed box, and the fixed box is fixed on the column by embedded bolts; the outer side of the fixed shaft is covered with a movable The box and the movable box are fixed on the beam through embedded bolts. 6. The position-limiting energy-dissipating structure according to any one of claims 1-5, characterized in that: a sliding position-limiting guide rail is welded between the two space-limiting plates on the upper part of the outer cylinder, and the two sections of the second chain are both Slidingly connected with the sliding limit guide rail. 7. A construction method for a position-limiting energy-dissipating structure according to claim 6, characterized in that it comprises the following steps: Install the roller, weld the roller welded with two limit plates, the first connecting steel plate and the second connecting steel plate to the angle between the beam and the column, install the fixed pulley and the fixed box on the column, and install the fixed shaft and the movable box mounted on beams; Use the limit adjustment ruler to install the drive chain. The initial length of the first chain in the first section and the initial length of the first chain in the third section are both longer than the actual required length. The other chains are the set lengths. The limit adjustment ruler includes the clamp And the adjustment plate, the fixture is C-shaped, the fixture includes two first horizontal plates and side plates, the two first horizontal plates are parallel, the two ends of the side plates are respectively connected with the two first horizontal plates, and one of the first horizontal plates Bolt holes are respectively opened on the plate and the side plates, the adjusting plate is an L-shaped plate, the adjusting plate includes a vertical plate and a second horizontal plate, a long hole is opened on the vertical plate, and a U-shaped adjusting groove is opened on the second horizontal plate, The U-shaped adjusting groove is a groove through which the first chain cannot pass but the second chain can pass. The long holes on the vertical plate and the bolt holes on the side plates are connected by adjusting bolts. There is a scale on the vertical plate of the adjustment plate; pass the second chain through the sliding limit guide rail and the two limit holes on the two limit plates respectively, and hang the second section of the first chain on the fixed pulley , put the torsion spring on the fixed shaft, weld one end of the torsion spring to the fixed shaft; insert the clamp into the limit plate parallel to the beam, the limit plate is located between the two first horizontal plates, take the locking bolt, Screw the locking bolt into the bolt hole on the first horizontal plate to fix the clamp on the limit plate parallel to the cross beam, loosen the adjusting bolt to make the vertical plate active, adjust the positioning pin to the horizontal, and adjust the position of the vertical plate so that The distance from the bottom surface of the second cross plate to the bottom surface of the limit plate parallel to the cross beam reaches the set distance, tighten the adjusting bolt, push the second chain below the limit plate parallel to the cross beam into the U-shaped adjustment groove, and pull the first From the head end of the first chain, until the first chain of the third section is on the U-shaped adjustment groove, until the drive chain cannot be pulled, put the end of the first chain of the third section away from the second chain and the other end of the torsion spring Welding, so that the first chain of the third section is in a fully extended state, and the torsion spring is in a natural state, weld the end of the first chain of the first section away from the second chain to the crossbeam, so that the drive chain is in a fully extended state, and cut off the first chain One section of the first chain and the excess part of the third section of the first chain, loosen the locking bolts on the first horizontal plate, and remove the limit adjustment ruler from the limit plate.