JP2020193538A - Expandable ladder, expandable ladder manufacturing method, and underground work support system - Google Patents

Abstract

To provide an expandable ladder which can reduce its weight.SOLUTION: An expandable ladder has a support rod 2 and a cross rail 6. The support rod 2 has an external cylindrical body 4 and an internal cylindrical body 5 connected to both ends of the external cylindrical body 4. The internal cylindrical body 5 can be housed in the external cylindrical body 4 in a nested fashion. The expandable latter has the plurality of internal cylindrical bodies 5 each having different thickness. The internal cylindrical bodies 5 are connected so that the thickness is gradually reduced toward the end and becomes the narrowest at a tip end. The external cylindrical body 4 has a hinge portion 4a which allows the external cylindrical body 4 to be folded. The support rod 2 is formed of magnesium alloy.SELECTED DRAWING: Figure 1

Description

The present invention relates to a telescopic ladder, a method for manufacturing the telescopic ladder, and an underground work support system using the telescopic ladder.

Patent Document 1 discloses a telescopic ladder including a pair of columns and a plurality of cross rails provided between the columns. The support of this telescopic ladder is configured by connecting multiple tubular bodies with different diameters so that they can be stored in a nested manner, and the length can be easily changed between extension and contraction like a feeding rod. Can be done.

JP-A-2019-35289

By the way, the telescopic ladder of Patent Document 1 is a so-called unidirectional extension type that extends only in one direction. Therefore, the tubular body located at one end (for example, the base end) is the thickest, and the tubular body located at the other end is the thinnest. In the case of such a one-way swing type, there is no particular problem if the number of joints of the tubular body is small, but if the number of joints is large, the tubular body on the base end side may become thicker than necessary and the weight may increase.

Therefore, an object of the present invention is to provide a telescopic ladder that can reduce the weight.

The telescopic ladder 1 of the present invention includes a support column 2 and a cross rail 6, and the support column 2 includes an outer cylinder body 4 and an inner cylinder body 5 connected to both ends of the outer cylinder body 4, respectively. The body 5 is characterized in that it can be accommodated in the outer cylinder 4 in a nested manner.

The telescopic ladder 1 includes a plurality of inner cylinders 5 having different thicknesses, and the inner cylinders 5 are connected so as to gradually become thinner toward the end and the tip becomes the thinnest. Is preferable.

Further, it is preferable that the outer cylinder 4 is provided with a hinge portion 4a that allows the outer cylinder 4 to be folded.

Further, it is preferable that the support column 2 is made of a magnesium alloy.

The method for manufacturing a telescopic ladder of the present invention is characterized in that a support column 2 formed by cold-molding a hot-formed raw pipe is used.

The underground work support system of the present invention is connected to any of the above telescopic ladders 1, a wireless connection means 11 that wirelessly connects to an Internet line, and a wireless connection means 11 to construct a wireless communication environment in a cable tunnel 30. When the telescopic ladder 1 is installed in the manhole 20 with the relay means 12, the wireless connecting means 11 is located in a portion of the telescopic ladder 1 protruding above the ground, and the relay means is located in a portion located in the cable tunnel 30 of the telescopic means. It is characterized in that 12 is located.

Further, in another underground work support system of the present invention, any of the above-mentioned telescopic ladders 1, a wireless connecting means 11 that wirelessly connects to the communication network 40, and a video capturing means 14 that connects to the wireless connecting means 11 are provided. When the telescopic ladder 1 is installed in the manhole 20 and a part of the telescopic ladder 1 is lowered into the cable tunnel 30, the wireless connecting means 11 and the video capturing means 14 are located on the portion of the telescopic ladder 1 protruding above the ground. It is characterized by that.

In another underground work support system of the present invention, any of the above-mentioned telescopic ladders 1, a wireless connection means 11 for wirelessly connecting to the communication network 40, and a position grasping means 16 for grasping the position of the telescopic ladder 1 are provided. When the telescopic ladder 1 is installed in the manhole 20 and a part of the telescopic ladder 1 is lowered into the cable tunnel 30, the wireless connection means 11 and the position grasping means 16 are located on the portion of the telescopic ladder 1 protruding above the ground. It is characterized by.

In yet another underground work support system of the present invention, one of the above telescopic ladders 1, the identification code 15 attached to the manhole 20, the database accumulating the information corresponding to the identification code 15, and the identification code are input. It is characterized in that it includes an input means for outputting information and an output means for outputting information based on the identification code 15.

The telescopic ladder of the present invention includes an outer cylinder and an inner cylinder connected to both ends of the outer cylinder, and the inner cylinder can be nested inside the outer cylinder. That is, since it is a so-called bidirectional feeding type, it is possible to reduce the weight as compared with the one-way feeding type.

When the entire ladder is regarded as a simple beam, a large bending moment is applied near the center, and almost no bending moment is applied near the ends. Therefore, if the inner cylinders are connected so that the inner cylinders gradually become thinner toward the end and the tip becomes the thinnest, the weight can be reduced while reducing the stress degree.

If the outer cylinder is provided with a hinge portion that allows the outer cylinder to be folded, the size can be further reduced and the outer cylinder can be easily carried.

In addition, if the columns are made of magnesium alloy, it is easier to reduce the weight.

Cold forming a hot-formed raw tube improves mechanical performance. Therefore, according to the method for manufacturing the telescopic ladder of the present invention, it is easy to reduce the weight.

In the underground work support system of the present invention, when the telescopic ladder is installed in a manhole, the wireless connecting means is located in the portion of the telescopic ladder protruding above the ground, and the relay means is located in the portion of the telescopic ladder located in the cave. , Communication with the ground can be secured via the communication network even in the cave.

Further, in the other underground work support system of the present invention, when the telescopic ladder is installed in the manhole and a part of the telescopic ladder is lowered into the cave, the wireless connection means and the image capturing means are connected to the portion of the telescopic ladder protruding above the ground. Since the ladder is located, the ascent and descent of the worker can be monitored remotely, and the safety of the worker can be ensured.

In another underground work support system of the present invention, when a telescopic ladder is installed in a manhole and a part of the telescopic ladder is lowered into a cave, a wireless connection means and a position grasping means are provided on a portion of the telescopic ladder protruding above the ground. Because it is located, the position of the telescopic ladder can be grasped remotely.

Yet another underground work support system of the present invention outputs an identification code attached to the manhole, a database accumulating information corresponding to the identification code, an input means for inputting the identification code, and information based on the identification code. Since it is equipped with an output means, the information necessary for work can be easily retrieved from the database.

FIG. 1A is a schematic view of a telescopic ladder according to an embodiment of the present invention, FIG. 1A shows a state of extension, FIG. 1B shows a state of contraction, and FIG. 1C shows a state of folding. It is an enlarged sectional view of the main part which shows the retaining mechanism. FIG. 3A is an enlarged cross-sectional view of a main part showing a locking mechanism, where FIG. 3A is when unlocked and FIG. 3B is when locked. It is the schematic of the underground work support system which concerns on one Embodiment of this invention. It is a block diagram of the said underground work support system. It is the schematic of the underground work support system which concerns on other embodiment of this invention. It is the schematic of the underground work support system which concerns on another embodiment of this invention. It is the schematic of the underground work support system which concerns on still another Embodiment of this invention.

Next, one embodiment of the telescopic ladder 1 will be described in detail with reference to the drawings. As shown in FIGS. 1A and 1B, the telescopic ladder 1 of the present invention includes a pair of columns 2 and 2 arranged substantially parallel to each other, and a plurality of cross rails 6 provided between the pair of columns 2 and 2. It has.

The support column 2 is composed of a tubular body 3. The tubular body 3 includes an outer tubular body 4 and an inner tubular body 5 connected to both ends of the outer tubular body 4, respectively.

The outer cylinder 4 has a substantially cylindrical shape having openings at both ends in the axial direction. Further, as shown in FIG. 1C, a hinge portion 4a that allows the outer cylinder 4 to be folded is provided at a substantially central portion in the axial direction. Moving means 4b such as casters and wheels are provided in the vicinity of the hinge portion 4a so that the hinge portion 4a can be easily transported in a folded state.

The inner cylinder 5 has a substantially cylindrical shape. As shown in FIG. 1B, the inner cylinder 5 can be accommodated in the outer cylinder 4 in a nested manner. Specifically, the first inner cylinder 5 having substantially the same inner diameter (inner dimension) and outer diameter (outer dimension) of the outer cylinder 4 is slidably connected to both ends of the outer cylinder 4, respectively. .. Further, the second inner cylinder 5 having substantially the same inner diameter and outer diameter of the first inner cylinder 5 is located at the end of the first inner cylinder 5 (on the side opposite to the side connected to the outer cylinder 4). It is slidably connected to the end). In the same manner below, the plurality of inner cylinders 5 are connected. That is, a plurality of inner cylinders 5 having different outer diameters (thicknesses) are connected to each other so that the outer cylinder portion is the thickest, gradually becomes thinner toward the end portion, and the tip portion becomes the thinnest. In the telescopic ladder 1 shown in FIG. 1, the sixth inner cylinder 5 (n1 to n6 shown in FIG. 1A) is on the side located below the outer cylinder 4 when the ladder is used (extended). Up to the 7th inner cylinder 5 (n1 to n7 shown in FIG. 1A) is connected to the side located at. However, the number of inner cylinders 5 to be connected can be appropriately changed according to the required length of the ladder.

The tubular body 3 is provided with a retaining mechanism 7 for preventing the connected tubular body 3 from coming off. Specifically, as shown in FIG. 2, an inner protrusion 7a is provided on the large diameter side (the side where the numbers of the outer cylinder 4 and the adjacent inner cylinder 5 are smaller than those of the first inner cylinder), and the inner protrusion 7a is provided on the small diameter side. An outer protruding portion 7b is provided on (the first inner cylinder portion with respect to the outer cylinder 4 and the side where the numbers of the adjacent inner cylinders 5 are larger), and when the inner cylinder 5 on the smaller diameter side is pulled out by a predetermined amount, the inner protruding portion is provided. The 7a and the outer protrusion 7b are engaged with each other so that they cannot be pulled out any further.

Further, the telescopic ladder 1 of the present invention includes a lock mechanism 8 for maintaining the pulled-out state of the inner cylinder 5. As shown in FIG. 3, the lock mechanism 8 includes a pin 8a urged by an urging means 8b such as a spring, and a pin hole 8c. The urging means 8b and the pin 8a are arranged in the tubular body 3 on the small diameter side, and the pin hole 8c is provided in the tubular body 3 on the large diameter side. Then, a predetermined amount of the tubular body 3 on the small diameter side is pulled out, and when the pin 8a approaches the pin hole 8c, the tubular body 3 on the small diameter side is automatically inserted into the pin hole 8c by the urging force of the urging means 8b. Axial movement is regulated (see FIG. 3B). The lock mechanism 8 is not limited to this, and various known lock mechanisms can be adopted.

Returning to FIG. 1, the cross rail 6 has a substantially square tubular shape, and is provided so as to connect the outer cylinders 4 to each other and the inner cylinders 5 to each other. The cross rails 6 are substantially parallel to each other. The number of cross rails 6 connecting the outer cylinders 4 to each other is four, and the number of cross rails 6 connecting the inner cylinders 5 to each other is one.

As the material of the support column 2 and the cross rail 6, metal or plastic can be adopted. Further, different materials may be used for the support column 2 and the cross rail 6. From the viewpoint of ensuring strength and reducing weight, it is preferable to use a magnesium alloy. Specifically, AZ31 is preferable.

However, if AZ31 is used as it is, the mechanical performance may be inferior to that of the aluminum alloy (A6061TD-T8) generally used as the material of the ladder. Specifically, when comparing the yield point stress (0.2% proof stress), AZ31 is lower. Therefore, the support column 2 (cylindrical body 3) is manufactured as follows.

First, a raw tube is made by hot forming (hot extrusion). Subsequently, cold molding (cold drawing) is performed to form the tubular body 3. Cold forming is carried out so that the cross-sectional reduction rate is reduced by 10 to 20%, preferably 12 to 18%, and more preferably 14 to 15%. The cross-sectional reduction rate is (A0-A1) / A0 when the cross-sectional area of the raw pipe before cold forming is A0 and the cross-sectional area of the raw pipe (cylindrical body 3) after cold forming is A1. It is a value calculated by. The following is a comparison of mechanical performance.

Since the tensile strength of the aluminum alloy (A6061TD-T8) is 265 MPa and the 0.2% proof stress is 190 MPa, it can be seen that sufficient strength is obtained after cold forming. Further, since the cross-sectional reduction rate is kept within a predetermined range, it is possible to suppress breakage and cracking during cold forming while improving mechanical performance.

It is not necessary to perform cold forming on the cross rail 6. However, cold molding may be performed.

Subsequently, the underground work support system 10 using the telescopic ladder 1 will be described. As shown in FIGS. 4 and 5, the underground work support system 10 is connected to the telescopic ladder 1, the wireless connecting means 11 that wirelessly connects to the communication network 40, and the wireless connecting means 11, and is wireless in the cable tunnel 30. It is provided with a relay means 12 for constructing a communication environment.

Then, when the telescopic ladder 1 is installed in the manhole 20 and a part of the telescopic ladder 1 is lowered into the cable tunnel 30, the wireless connecting means 11 is located in the portion of the telescopic ladder 1 protruding above the ground, and the telescopic means cave The relay means 12 is configured to be located in a portion located in the road 30. More specifically, when a descent ladder is installed in the manhole 20, it is projected from the manhole 20 to the ground side by 600 mm or more, and the wireless connecting means 11 is arranged in the protruding portion. Further, the relay means 12 is arranged in a portion located in the horizontal hole-shaped tunnel 30 with respect to the vertical hole-shaped manhole 20. The wireless connecting means 11 and the relay means 12 may be attached in advance to the telescopic ladder 1 in the contracted state, or may be attached after the telescopic ladder 1 is extended.

The communication network 40 includes, for example, the Internet, but other networks may also be used. Examples of the wireless connection means 11 include a portable mobile router. Examples of the relay means 12 include a wireless LAN router. It is preferable that the wireless connection means 11 and the relay connection means are connected by wire. However, it may be a wireless connection.

(Securing communication underground)
By using the underground work support system 10 having the above configuration, it is possible to secure communication with the ground via the communication network 40 even in the cable tunnel 30.

Therefore, an information terminal 13 (wearable device, smart device, etc., which is a wearable device, a smart device, etc., and is a calculation unit (CPU), a storage medium (RAM and / or ROM, HDD, SSD, etc.) and an input unit (keyboard, joystick, etc.) that can be connected to the relay means 12 , A microphone, etc.) and an output unit (display and / or speaker) at least) can be provided to the worker, or can be connected to the relay means 12 in a portion of the telescopic ladder 1 located in the cable tunnel 30. By attaching the image capturing means 14, various things can be done.

(Remote instruction)
For example, the command center 50 on the ground can give instructions to the workers in the cable tunnel 30 in real time. If it is a spectacle-type wearable device and the lens portion is provided with a display, the work content can be displayed on the display in real time. Further, since the worker in the cable tunnel 30 can send information to the command center 50 on the ground, if the information terminal 13 has a camera function, the video of the work can be sent to the command center 50 in real time. it can. As a method of transmitting an image, a dedicated camera may be provided separately, and the camera may be directly connected to the relay means 12 wirelessly, or may be connected with a communication terminal interposed between them. In this way, since two-way communication is possible in real time, it is possible to reduce the number of workers dispatched to the site and improve work efficiency.

(Understanding the situation in cable tunnel 30)
In addition, the situation in the cable tunnel 30 can be grasped in real time by the image capturing means 14 attached to the telescopic ladder 1. Therefore, the safety of workers can be ensured.

Subsequently, the underground work support system 10A according to a different embodiment of the present invention will be described. As shown in FIG. 6, the underground work support system 10A is provided with a wireless connection means 11 and a video capturing means 14, a telescopic ladder 1 is installed in a manhole 20, and a part of the telescopic ladder 1 is partly connected to a cable tunnel 30. The wireless connecting means 11 and the video capturing means 14 are configured to be located on the portion of the telescopic ladder 1 protruding above the ground when lowered inward. Specifically, when a ladder for descent is installed in the manhole 20, it is projected from the manhole 20 to the ground side by 600 mm or more, and the wireless connecting means 11 and the video capturing means 14 are arranged in the protruding portion. .. The video shooting means 14 is, for example, a surveillance camera, and includes a shooting unit for shooting a moving image or a still image, a calculation unit for converting the shot video into digital data, and an output unit for outputting the digital data to the outside. There is. The digital data is sent to the command center 50 in real time via the wireless connection means 11 that wirelessly connects to the communication network 40. The video capturing means 14 itself may include the wireless connecting means 11. The video capturing means 14 mainly faces downward (manhole 20 side).

(Ensuring safety)
In the underground work support system 10A having the above configuration, it can be confirmed in real time from the command center 50 on the ground whether or not the worker can go up and down the ladder without any problem.

Subsequently, the underground work support system 10B according to a further different embodiment of the present invention will be described. As shown in FIG. 7, the underground work support system 10B includes a wireless connection means 11 for wirelessly connecting to the communication network 40 and a position grasping means 16 for grasping the position of the telescopic ladder 1, and the telescopic ladder 1 is provided with a manhole 20. When a part of the telescopic ladder 1 is lowered into the cave 30, the wireless connecting means 11 and the position grasping means 16 are located at a portion of the telescopic ladder 1 protruding above the ground. Specifically, when a ladder for descent is installed in the manhole 20, it is projected from the manhole 20 to the ground side by 600 mm or more, and the wireless connection means 11 and the position grasping means 16 are arranged in the protruding portion. .. Examples of the position grasping means 16 include a transmitter using satellite positioning such as GPS and WiFi (registered trademark) positioning. The position information grasped by the position grasping means 16 is sent to the command center 50 through the wireless connecting means 11 integrated with or separate from the position grasping means 16.

(Position confirmation, safety confirmation, worker recovery)
In the underground work support system 10B, the current location of the telescopic ladder 1 can be grasped in real time. Therefore, the command center 50 can always keep track of where the work is being carried out. For example, if the location of the telescopic ladder 1 does not change for a long time, it can be grasped that a problem may have occurred. The same applies when the worker who should be working cannot be contacted. Further, by knowing the position of the telescopic ladder 1, it is possible to easily grasp where to pick up after the work is completed.

Subsequently, the underground work support system 10C according to a further different embodiment of the present invention will be described. In this underground work support system 10C, as shown in FIG. 8, the identification code 15 attached to the manhole 20, the database accumulating the information corresponding to the identification code 15, the input means for inputting the identification code 15, and the identification It is provided with an output means for outputting information based on the code 15. The identification code 15 is, for example, a barcode or a two-dimensional code. The input means is, for example, a camera or a bar code scanner built in the information terminal 13. The output means is, for example, the display of the information terminal 13. The database is recorded on a storage medium mounted on the information terminal 13. However, it may be recorded in an external device, for example, it may be recorded in a device installed at the command center 50. In this case, in order to secure communication with the ground, the underground work support system 10B is further connected to the wireless connection means 11 that wirelessly connects to the communication network 40 and the wireless connection means 11, and is wireless in the cable tunnel 30. It is provided with a relay means 12 for constructing a communication environment. The information in the database is, for example, location information, a format for inputting work results, and precautions during work.

(Simplification of work)
In the underground work support system 10C, the worker inputs the identification code 15 attached to the manhole 20 into the information terminal 13, so that the position information of the manhole 20, the format for inputting the work result, and the precautions for work are taken into consideration. Can be called, and work can be done efficiently. Further, if the position information is transmitted to the command center 50, it is possible to grasp in real time which manhole 20 the work is being performed on. In this case, for example, when a large number of workers who are working separately at a plurality of places are picked up by the vehicle, the vehicle can be efficiently run by going through the shortest distance. Further, an identification code 15a may be attached to the telescopic ladder 1 to assist the input of the work result into the format. For example, a person who uses the telescopic ladder 1 may be registered in advance in the database, and the name of the worker may be automatically input to the format by inputting the identification code 15a into the information terminal 13.

Each of the underground work support systems 10 to 10C may be separately provided with a lighting 17 that illuminates the inside of the cable tunnel 30, a portable electrode supply means 18 such as a generator or a battery, and a sensor 19 such as a gas sensor. If the electrode supply means 18 is attached to the telescopic ladder 1, electric power can be appropriately supplied to a device that requires electric power. The electrode supply means 18 is preferably arranged on the ground. A power cable is used to connect to each device, but wireless power supply may also be used. If a sensor 19 such as a gas sensor is provided, the safety of work in the cable tunnel 30 can be further enhanced. It is preferable that the sensor 19 is arranged underground, particularly in the cable tunnel 30. It may be attached to the telescopic ladder 1 in advance.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. For example, the cross-sectional shape of the outer cylinder 4 and the inner cylinder 5 of the support column 2 is not limited to a circle, and may be a triangle, a rectangle, or a polygon of a pentagon or more.

1 Telescopic ladder 2 Strut 3 Cylindrical body 4 Outer tubular body 4a Hinge part 4b Moving means 5 Inner cylinder body 6 Horizontal rail 7 Retaining mechanism 7a Inner protruding part 7b Outer protruding part 8 Lock mechanism 8a Pin 8b Biasing means 8c Pin hole 10, 10A, 10B, 10C Underground work support system 11 Wireless connection means 12 Relay means 13 Information terminal 14 Video shooting means 15 Identification code (for manhole)
15a Identification code (for telescopic ladder)
16 Positioning means 17 Lighting 18 Power supply means 19 Sensor 20 Manhole 30 Cave 40 Communication network 50 Command center

Claims (9)

With stanchions
Equipped with a cross rail
The columns include an outer cylinder and an inner cylinder connected to both ends of the outer cylinder.
A telescopic ladder in which the inner cylinder can be nested inside the outer cylinder. It has multiple inner cylinders with different thicknesses,
The telescopic ladder according to claim 1, wherein the inner cylinders are connected so that the inner cylinders gradually become thinner toward the end and the tip becomes the thinnest. The telescopic ladder according to claim 1 or 2, wherein the outer cylinder is provided with a hinge portion that allows the outer cylinder to be folded. The telescopic ladder according to any one of claims 1 to 3, wherein the support is made of a magnesium alloy. A method for manufacturing a telescopic ladder, wherein the telescopic ladder according to claim 4 uses a support column formed by cold-molding a hot-formed raw pipe. The telescopic ladder according to any one of claims 1 to 5,
Wireless connection means to wirelessly connect to the communication network,
It is equipped with a relay means that is connected to the wireless connection means and builds a wireless communication environment in the cave.
When the telescopic ladder is installed in the manhole and a part of the telescopic ladder is lowered into the cave, the wireless connection means is located in the part of the telescopic ladder protruding above the ground, and the relay means is located in the part of the telescopic means located in the cave. Located, underground work support system. The telescopic ladder according to any one of claims 1 to 5,
Wireless connection means to wirelessly connect to the communication network,
Equipped with a wireless connection means and a video shooting means to connect
An underground work support system in which when a telescopic ladder is installed in a manhole and a part of the telescopic ladder is lowered into a cave, a wireless connection means and a video shooting means are located on the protruding part of the telescopic ladder. The telescopic ladder according to any one of claims 1 to 5,
Wireless connection means to wirelessly connect to the communication network,
Equipped with a position grasping means to grasp the position of the telescopic ladder,
An underground work support system in which a wireless connection means and a position grasping means are located in a part of the telescopic ladder that protrudes above the ground when a telescopic ladder is installed in a manhole and a part of the telescopic ladder is lowered into a cave. The telescopic ladder according to any one of claims 1 to 5,
The identification code attached to the manhole and
A database that stores information corresponding to the identification code and
Input means for entering the identification code and
An underground work support system equipped with an output means that outputs information based on an identification code.

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