A tower flexible guide rail anti-high fall device and use method

Abstract

This invention discloses a fall protection device for a flexible guide rail on a steel tower and its usage method. The fall protection device includes a specially designed hook; the hook comprises a main hook and a secondary hook; one end of the main hook is connected to a pressure tongue via a rotating shaft, and the other end has a connecting shaft and a pin hole on each side; the connecting shaft is rotatably connected to the secondary hook, and the secondary hook has a pin that passes through the pin hole and connects to the main hook's pin; a lifting plate is slidably connected to the side of the main hook away from the secondary hook; the lifting plate has a first hole and a second hole at each end; the first hole connects to the flexible guide rail, and the second hole is detachably connected to a drone's throwing device. This invention solves the technical problem of existing technologies failing to guarantee personal safety and posing safety hazards. This invention utilizes a mechanical structure to complete the locking and releasing of the specially designed hook, resulting in high reliability.

Description

Technical Field

[0001] This invention relates to the field of anti-fall-from-height technology for flexible guide rails on iron towers, and particularly to an anti-fall-from-height device and its usage method for flexible guide rails on iron towers. Background Technology

[0002] The number of power transmission towers is steadily increasing every year, but most of the operating towers are not equipped with fall arrest rails. Personnel climbing the towers lack convenient and easy-to-use fall arrest tools, which leads to occasional falls from heights during the process of climbing the towers.

[0003] Currently, there are two main fall protection schemes: one is that workers use safety belts in a standardized manner, and as the workers move up the tower, they alternately use the main rope and the spare tail rope of the safety belt to attach to the foot spikes to achieve all-time protection for high-altitude operations; the other is that one worker climbs the tower first and installs a flexible temporary guide rail at a high point, and other workers install speed-differential fall arresters on the guide rail to achieve all-time protection during the process of climbing up and down the tower. However, the installation of fall arresters in the above two methods is usually done by manually climbing up the tower. The tower climbing operation requires the first person to climb up the tower alone without the protection of a fall arrest rope to install the fall arrest rope, and the last person to remove the fall arrest rope also has no protective measures, so personal safety cannot be guaranteed and there are safety hazards. Summary of the Invention

[0004] This invention provides a flexible guide rail device for preventing falls from heights on iron towers and its usage method. It solves the technical problem that existing technologies usually require manual climbing to the iron tower, where the first person has to climb the tower alone without the protection of a fall arrest rope to install the fall arrest rope, and the last person has no protective measures after removing the fall arrest rope, resulting in a lack of personal safety and potential safety hazards.

[0005] The first aspect of the present invention provides a device for preventing falls from height on a flexible guide rail for iron towers, the device comprising a specially designed hook;

[0006] The specially designed hook includes a main hook and a secondary hook;

[0007] One end of the main hook is connected to the pressure tongue via a rotating shaft, and the other end is provided with a connecting shaft and a pin hole on both sides respectively;

[0008] The connecting shaft is rotatably connected to the secondary hook, and the secondary hook is provided with a pin that passes through the pin hole and is connected to the pin of the main hook.

[0009] A lifting plate is slidably connected to the side of the main hook away from the auxiliary hook;

[0010] The lifting plate has a first hole and a second hole at each end;

[0011] The first hole is connected to the flexible guide rail, and the second hole is detachably connected to the drone's throwing device.

[0012] Optionally, the secondary hook is provided with a pin groove;

[0013] Both ends of the pin groove are connected to one end of the return spring, and the other end of the return spring is connected to the pin.

[0014] Optionally, a connecting rod is provided at the top of one end of the secondary hook near the main hook;

[0015] A pulley is provided at the end of the connecting rod away from the secondary hook;

[0016] The auxiliary hook is symmetrically provided with pressure columns on both sides of the connecting rod, and the lower part of the pressure columns is rotatably connected to the auxiliary hook.

[0017] Optionally, the pressure column is rotatably connected to the secondary hook via a pressure column pivot.

[0018] Optionally, a through hole is provided at the center of the pin away from the return spring;

[0019] The bottom of the pressure column passes through the perforation and is connected to the pin.

[0020] Optionally, the iron tower flexible guide rail anti-fall device also includes an auxiliary rope;

[0021] One end of the auxiliary rope is installed on the pulley and wound around the two pressure columns, while the other end passes through the rope loop provided on the auxiliary hook.

[0022] Optionally, the two pressure columns are Y-shaped in the normal state.

[0023] Optionally, the lifting plate is provided with a lifting plate groove;

[0024] The main hook is equipped with a slider that is slidably connected to the lifting plate groove.

[0025] Optionally, the other end of the depressor tongue, away from the main hook, abuts against the secondary hook.

[0026] The second aspect of this invention provides a method of using a fall protection device for a flexible guide rail on a steel tower, comprising:

[0027] The second hole of the lifting plate is hooked by the drone's throwing device, and a special hook that is slidably connected to the lifting plate is transported to the target tower material.

[0028] When the main hook and auxiliary hook of the special hook are attached to the target tower material, the lifting plate is slid to the top of the lifting plate groove, and the pressure tongue is driven to rotate upward around the rotation axis so that the pressure tongue abuts against the auxiliary hook;

[0029] The speed difference fall arrestor on the flexible guide rail connected to the lifting plate is hooked onto the worker's safety belt.

[0030] As can be seen from the above technical solutions, the present invention has the following advantages:

[0031] This invention utilizes a mechanical structure to lock and release a specially designed hook, ensuring high reliability. The tool set can be quickly installed and disassembled without the need for drone assistance. It provides continuous protection for workers ascending and descending the tower, facilitating continuous movement without the need for individual safety checks, thus achieving inherent safety. Eliminating the need for individual safety checks during tower ascent and descent reduces the requirements for personnel skills and safety awareness, and speeds up the process. The flexible guide rail eliminates the need for personnel to climb the tower for installation and removal, providing fall protection for all personnel ascending and descending the tower. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of a high-altitude fall prevention device for a flexible guide rail on a steel tower, provided in an embodiment of the present invention.

[0034] Figure 2 A left view of a flexible guide rail device for preventing falls from heights on a steel tower, provided in an embodiment of the present invention;

[0035] Figure 3 A perspective view of a flexible guide rail device for preventing falls from heights on a steel tower, provided in an embodiment of the present invention;

[0036] Figure 4 Rear view of a flexible guide rail anti-fall device for iron towers provided in an embodiment of the present invention;

[0037] Figure 5 A cross-sectional view of components such as the pin groove, pin, and return spring under normal conditions provided in an embodiment of the present invention;

[0038] Figure 6A cross-sectional view of components such as the pin groove, pin, and return spring when the pressure column is in the closing position, as provided in an embodiment of the present invention;

[0039] Figure 7 This is a flowchart illustrating the steps of using a fall protection device for a flexible guide rail on a steel tower, as provided in an embodiment of the present invention.

[0040] The meanings of the reference numerals in the attached figures are as follows:

[0041] 1. Main hook; 2. Secondary hook; 3. Pressure tongue; 4. Lifting plate; 4-1. Second hole; 4-2. First hole; 5. Lifting plate groove; 6. Pressure column; 7. Connecting rod; 8. Rope ring; 9. Column pin; 10. Rotating shaft; 11. Tower material; 12. Return spring; 13. Connecting shaft; 14. Pressure column rotating shaft; 15. Pulley; 16. Column pin groove; 17. Pin hole. Detailed Implementation

[0042] This invention provides a flexible guide rail device and method for preventing falls from heights on iron towers. It addresses the technical problem that existing technologies typically require manual climbing of the iron tower, where the first person must climb the tower alone without a fall arrest rope to install it, and the last person has no safety measures after removing the fall arrest rope, resulting in unsafe personal safety and potential safety hazards.

[0043] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0044] Example 1

[0045] Please see Figure 1-4 , Figure 1 This is a structural schematic diagram of a flexible guide rail device for preventing falls from heights on iron towers, provided as an embodiment of the present invention.

[0046] This invention provides a fall protection device for a flexible guide rail on a steel tower. The device includes a specially designed hook. The hook includes a main hook 1 and a secondary hook 2. One end of the main hook 1 is connected to a pressure tongue 3 via a rotating shaft 10, and the other end has a connecting shaft 13 and a pin hole 17 on both sides. The connecting shaft 13 is rotatably connected to the secondary hook 2, and the secondary hook 2 has a pin 9 that passes through the pin hole 17 and is connected to the main hook 1 by a pin. A lifting plate 4 is slidably connected to the side of the main hook 1 away from the secondary hook 2. The lifting plate 4 has a first hole 4-2 and a second hole 4-1 at both ends. The first hole 4-2 is connected to the flexible guide rail, and the second hole 4-1 is detachably connected to the throwing device of a drone.

[0047] It should be noted that the fall protection device for the flexible guide rail of the iron tower includes a specially designed hook and a flexible guide rail. The specially designed hook mainly consists of a main hook 1 and an auxiliary hook 2, see reference. Figure 1 As shown, one end of the main hook 1 is connected to the pressure tongue 3 via a rotating shaft 10, and the other end is provided with a connecting shaft 13 and a pin hole 17. The main hook 1 is fixedly connected to the auxiliary hook 2 via the connecting shaft 13. The pin 9 on the auxiliary hook 2 passes through the pin hole 17 and is connected to the pin of the main hook 1, which is a detachable connection. Under normal circumstances, the pin 9 is inserted into the pin hole 17, and the main hook 1 and the auxiliary hook 2 cannot rotate relative to each other. At this time, the main hook 1 and the auxiliary hook 2 can rotate through the connecting shaft 13, and the other end of the pressure tongue 3 away from the main hook 1 is not in contact with the auxiliary hook 2. The pressure tongue 3 and the auxiliary hook 2 are in an open state, which facilitates the subsequent hanging of the special hook on the tower material 11.

[0048] See Figure 1 As shown, a lifting plate 4 is slidably connected to the side of the main hook 1 away from the auxiliary hook 2. The two ends of the lifting plate 4 are respectively provided with a first hole 4-2 and a second hole 4-1. The first hole 4-2 is connected to the flexible guide rail, and the second hole 4-1 is detachably connected to the drone's throwing device. A speed difference fall arrestor is suspended on the flexible guide rail and used to hook onto the safety belt of the operator.

[0049] Specifically, when a flexible guide rail anti-fall device is needed to be installed on tower material 11, the drone's throwing device is first used to clamp the second hole 4-1 of the lifting plate 4, raising the special hook. During the lifting process, due to gravity, the main hook 1, auxiliary hook 2, and pressure tongue 3 are all fixed to the bottom of the lifting plate groove 5 of the lifting plate 4. At the same time, the special hook will also lift the flexible guide rail and auxiliary rope. After reaching the predetermined working height, because the opening of the special hook is large enough, the drone only needs to be moved to the approximate position to remotely release the throwing device, suspending the special hook on the tower material 11 (such as angle steel). Figure 2 As shown.

[0050] At this time, the special hook is supported by the tower material 11, and the lifting plate 4 and the flexible guide rail will move downward along the lifting plate slide 5 due to gravity. At the same time, the pressure tongue 3 will rotate upward around the rotating shaft 10. When the pressure tongue 3 contacts the auxiliary hook 2, the opening of the special hook will be completely closed. At this time, the main hook 1, auxiliary hook 2, pressure tongue 3 and other components will reach the top of the lifting plate slide 5 due to relative movement. The workers below the tower will apply a pulling force to the lifting plate 4 by tightening the flexible guide rail to make the closure more reliable. The installation is thus completed.

[0051] Workers can use a speed-differential fall arrestor connected to the flexible guide rail and hooked onto their safety belt to achieve fall protection throughout the entire process of ascending and descending the tower. At a normal speed, personnel can move freely. However, in the event of a fall and excessive descent speed, the speed-differential fall arrestor will lock onto the flexible guide rail in time, providing protection.

[0052] Example 2

[0053] Please see Figure 1-6 , Figure 1 This is a structural schematic diagram of a flexible guide rail device for preventing falls from heights on iron towers, provided as an embodiment of the present invention.

[0054] This invention provides a fall protection device for a flexible guide rail on a steel tower. The auxiliary hook 2 is equipped with a pin groove 16; both ends of the pin groove 16 are connected to one end of a return spring 12, and the other end of the return spring 12 is connected to a pin 9. A connecting rod 7 is provided at the top of the auxiliary hook 2 near the main hook 1; a pulley 15 is provided at the end of the connecting rod 7 away from the auxiliary hook 2; pressure columns 6 are symmetrically arranged on both sides of the connecting rod 7 on the auxiliary hook 2, and the lower part of the pressure columns 6 is rotatably connected to the auxiliary hook 2. The pressure columns 6 are rotatably connected to the auxiliary hook 2 via a pressure column pivot 14. A through hole is provided in the middle of the pin 9 away from the return spring 12; the bottom of the pressure column 6 passes through the through hole and connects to the pin 9. The fall protection device for the flexible guide rail on a steel tower also includes an auxiliary rope; one end of the auxiliary rope is installed on the pulley 15 and wound around the two pressure columns 6, and the other end passes through a rope loop 8 provided on the auxiliary hook 2. The two pressure columns 6 are Y-shaped in the normal state.

[0055] It should be noted that, for reference Figure 5 As shown, the secondary hook 2 is provided with a pin groove 16, and a return spring 12 is provided at both ends of the pin groove 16. The other end of the return spring 12 is connected to the pin 9. Under normal circumstances, the return spring 12 is in the extended state, and the two pins 9 approach or abut and insert into the pin hole 17, which facilitates the fixing of the main hook 1 and the secondary hook 2.

[0056] Specifically, a connecting rod 7 is provided at the top of the end of the auxiliary hook 2 closest to the main hook 1, and a pulley 15 is provided at the end of the connecting rod 7 furthest from the auxiliary hook 2. Two pressure posts 6 are symmetrically arranged on the auxiliary hook 2, located on either side of the connecting rod 7 and parallel to it. The lower middle parts of both pressure posts 6 are rotatably connected to the auxiliary hook 2 via pressure post pivots 14. A through hole is provided at the middle of the two pins 9 near each other, and the bottom of the pressure post 6 passes through the through hole and connects to the pin 9. (See reference...) Figure 4-5 As shown, under normal conditions, when the two pins 9 are close together, the two pressure pins 6 form a Y-shape. (See reference...) Figure 6 As shown, when it is necessary to separate the two pins 9, the two pressure pins 6 are brought close together. At the same time, the bottom of the pressure pin 6 drives the pin 9 to squeeze the return spring 12 and move to both ends of the pin slide groove 16. If the pin 9 was inserted into the pin hole 17 of the main hook 1 before the movement, when the pressure pin 6 drives the pin 9 to separate, the pin 9 will disengage from the pin hole 17, and the main hook 1 and the auxiliary hook 2 will resume rotational connection.

[0057] It should be noted that in order to bring the two pressure columns 6 together with the connecting rod 7, so that the bottom of the pressure column 6 drives the pin 9 to squeeze the return spring 12 and move it to both ends of the pin groove 16, the auxiliary rope wrapped around the two pressure columns 6 needs to be tightened. This will bring the two pressure columns 6 together and drive the pin 9 to squeeze the return spring 12 and move it to both ends of the pin groove 16.

[0058] Specifically, an auxiliary rope is tied to the pulley 15 on the connecting rod 7. The auxiliary rope is then wrapped around the pressure posts 6 on both sides of the connecting rod 7, and the other end of the auxiliary rope is passed through the rope loop 8 and hangs naturally to the ground, making it convenient for operators to retract the auxiliary rope. Under normal circumstances, the two pressure posts 6 are Y-shaped. When it is necessary to tighten the auxiliary rope on the pressure posts 6, the two pressure posts 6 are in a vertical position.

[0059] In practice, after the work is completed and all personnel descend from the tower, the auxiliary rope is pulled from below. Through the steering action of pulley 15, the tension of the auxiliary rope is applied to the two Y-shaped, open pressure columns 6. The pressure columns 6 rotate around the pressure column pivot 14, and the bottom of the pressure column 6 drives the pin 9 to compress the return spring 12, causing the pin 9 to move from the center to both sides. When the pin 9 completely disengages from the pin hole 17, the lock between the main hook 1 and the auxiliary hook 2 is released. Due to the supporting force of the tower material 11, the auxiliary hook 2 rotates upward around the connecting shaft 13. At this time, the special hook changes from closed to open again and falls due to gravity. The personnel use the flexible guide rail and auxiliary rope to control the falling speed of the special hook and retrieve the entire set of tools.

[0060] Example 3

[0061] Please see Figure 1 , Figure 1 This is a structural schematic diagram of a flexible guide rail device for preventing falls from heights on iron towers, provided as an embodiment of the present invention.

[0062] This invention provides a flexible guide rail device for preventing falls from heights on iron towers. A lifting plate 4 has a lifting plate groove 5; a slider that is slidably connected to the lifting plate groove 5 is provided on the main hook 1. The end of the pressure tongue 3 furthest from the main hook 1 abuts against the auxiliary hook 2.

[0063] It should be noted that, for reference Figure 1 As shown, the lifting plate 4 is provided with a lifting plate groove 5, and the main hook 1 is provided with a slider that is slidably connected to the lifting plate groove 5.

[0064] Specifically, when the drone's throwing device clamps the second hole 4-1 of the lifting plate 4, the special hook is lifted. During the lifting process, due to gravity, the main hook 1, the auxiliary hook 2, the pressure tongue 3 and other components are fixed at the bottom of the lifting plate slide 5 of the lifting plate 4.

[0065] Under normal circumstances, the pressure tongue 3 and the auxiliary hook 2 are in the open state. When the special hook is supported by the tower material 11, the lifting plate 4 and the flexible guide rail will move downward along the lifting plate groove 5 due to gravity. At the same time, the pressure tongue 3 will rotate upward around the rotating shaft 10. After the pressure tongue 3 and the auxiliary hook 2 come into contact / abut, the opening of the special hook will be completely closed.

[0066] Example 4

[0067] Please see Figure 7 , Figure 7 This is a flowchart illustrating the steps of using a fall protection device for a flexible guide rail on a steel tower, as provided in an embodiment of the present invention.

[0068] The present invention provides a method for using a fall protection device for a flexible guide rail on a steel tower, comprising the following steps:

[0069] Step 101: Hook the second hole 4-1 of the lifting plate 4 using the drone's throwing device, and transport the special hook that is slidably connected to the lifting plate 4 to the target tower material 11;

[0070] Step 102: When the main hook 1 and the auxiliary hook 2 of the special hook are attached to the target tower material 11, slide the lifting plate 4 to the top of the lifting plate groove 5, and drive the pressure tongue 3 to rotate upward around the rotating shaft 10 so that the pressure tongue 3 abuts against the auxiliary hook 2.

[0071] Step 103: Hook the speed difference fall arrestor on the flexible guide rail connected to the lifting plate 4 onto the worker's safety belt.

[0072] It should be noted that the drone's throwing device is first used to clamp the second hole 4-1 of the lifting plate 4, raising the special hook. During the lifting process, due to gravity, the main hook 1, auxiliary hook 2, and pressure tongue 3 will all be fixed at the bottom of the lifting plate groove 5 of the lifting plate 4. At the same time, the special hook will also lift the flexible guide rail and auxiliary rope. After reaching the predetermined working height, because the opening of the special hook is large enough, the drone only needs to be moved to the approximate position to remotely release the throwing device, suspending the special hook on the tower material 11 (such as angle steel).

[0073] At this time, the special hook is supported by the tower material 11, and the lifting plate 4 and the flexible guide rail will move downward along the lifting plate slide 5 due to gravity. At the same time, the pressure tongue 3 will rotate upward around the rotating shaft 10. When the pressure tongue 3 contacts the auxiliary hook 2, the opening of the special hook will be completely closed. At this time, the main hook 1, auxiliary hook 2, pressure tongue 3 and other components will reach the top of the lifting plate slide 5 due to relative movement. The workers below the tower will apply a pulling force to the lifting plate 4 by tightening the flexible guide rail, so that the side of the main hook 1 close to the auxiliary hook 2 will enter the insertion hole of the auxiliary hook 2 and push open the pins 9 on both sides until the pin hole 17 stops at the pin 9. Because the return spring 12 on the pin 9 returns to its original position, the closure is more reliable. The installation is thus completed.

[0074] Workers can use a speed-differential fall arrestor connected to the flexible guide rail and hooked onto their safety belt to achieve fall protection throughout the entire process of ascending and descending the tower. At a normal speed, personnel can move freely. However, in the event of a fall and excessive descent speed, the speed-differential fall arrestor will lock onto the flexible guide rail in time, providing protection.

[0075] After the work is completed and all personnel descend from the tower, they pull the auxiliary rope from below. Through the steering action of pulley 15, the tension of the auxiliary rope is applied to the two Y-shaped, open pressure columns 6. The pressure columns 6 rotate around the pressure column pivot 14, and the bottom of the pressure column 6 drives the pin 9 to compress the return spring 12, causing the pin 9 to move from the center to both sides. When the pin 9 completely disengages from the pin hole 17, the lock between the main hook 1 and the auxiliary hook 2 is released. Due to the supporting force of the tower material 11, the auxiliary hook 2 rotates upward around the connecting shaft 13. At this time, the special hook changes from closed to open again and falls due to gravity. The personnel use the flexible guide rail and auxiliary rope to control the falling speed of the special hook and retrieve the entire set of tools.

[0076] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0077] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for preventing falls from heights on flexible guide rails of iron towers, characterized in that, The iron tower flexible guide rail anti-fall device includes a specially designed hook; The specially designed hook includes a main hook and a secondary hook; One end of the main hook is connected to the pressure tongue via a rotating shaft, and the other end is provided with a connecting shaft and a pin hole on both sides respectively; The connecting shaft is rotatably connected to the secondary hook, and the secondary hook is provided with a pin that passes through the pin hole and is connected to the pin of the main hook. A lifting plate is slidably connected to the side of the main hook away from the auxiliary hook; The lifting plate has a first hole and a second hole at each end; The first hole is connected to the flexible guide rail, and the second hole is detachably connected to the drone's throwing device; The secondary hook is provided with a pin groove; Both ends of the pin groove are connected to one end of the return spring, and the other end of the return spring is connected to the pin. A connecting rod is provided at the top of the end of the secondary hook near the main hook; A pulley is provided at the end of the connecting rod away from the secondary hook; The auxiliary hook is symmetrically provided with pressure columns on both sides of the connecting rod, and the lower part of the pressure column is rotatably connected to the auxiliary hook; The pressure column is rotatably connected to the auxiliary hook via a pressure column pivot. The pin has a through hole at its center away from the return spring; The bottom of the pressure column passes through the perforation and is connected to the pin; The iron tower flexible guide rail anti-fall device also includes an auxiliary rope; One end of the auxiliary rope is installed on the pulley and wound around the two pressure columns, and the other end passes through the rope loop provided on the auxiliary hook; The two pressure columns are Y-shaped under normal conditions; The lifting plate is provided with a lifting plate groove; The main hook is provided with a slider that is slidably connected to the lifting plate groove; The other end of the depressor tongue, away from the main hook, abuts against the secondary hook.

2. A method of using the anti-falling device for flexible guide rail of iron tower according to claim 1, characterized in that, include: The second hole of the lifting plate is hooked by the drone's throwing device, and a special hook that is slidably connected to the lifting plate is transported to the target tower material. When the main hook and auxiliary hook of the special hook are attached to the target tower material, the lifting plate is slid to the top of the lifting plate groove, and the pressure tongue is driven to rotate upward around the rotation axis so that the pressure tongue abuts against the auxiliary hook; The speed difference fall arrestor on the flexible guide rail connected to the lifting plate is hooked onto the worker's safety belt.

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