Telescopic ladder with telescopic handrail

Abstract

To provide a ladder having a configuration which can be easily extended for use, can be easily shortened for storage at the time of recovery after use, and can also extend and contract a handrail body.SOLUTION: A ladder base member 101 including a pair of cylindrical strut bodies 110 and a horizontal cross-piece body 120 is used as a base unit, and the cylindrical strut bodies 110 of respective stages are successively connected slidably in the direction of a cylindrical axis, and a shortened storage state and an extended use state are provided. A lock mechanism 130 for temporarily fixing the ladder base members 101 so as not to be slidable and a lock release mechanism 140 for releasing the lock state of the lock mechanism 130 so as to be slidable are provided, and a cylindrical handrail body 150 is also assembled in a slidable manner. The handrail body 150 is also rotatable in the horizontal direction, and in the lock mechanism, a fitting pin 131 is fitted into a fitting hole 152 of the handrail body 150 while allowing the handrail body 150 to freely slide, extend, and rotate in the horizontal direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ladder that is telescopic in its length, and more particularly to a ladder that has a handrail that is also telescopic. [Background technology]

[0002] Hanging ladders are widely used for work such as manholes. Here, a hanging ladder for work refers to a type of ladder that is not fixed to a wall under normal circumstances, but is dynamically suspended from a suspension point when in use, and is removed and collected when use is finished. For example, there are hanging ladders for work that are suspended from a suspension point during work as a means of transportation to descend from a high place to a work site below, and hanging ladders for evacuation that are suspended from a suspension point during work as a means of evacuation for passengers to evacuate below in an emergency when it becomes necessary to evacuate to the outside of a building or train. There are also many other variations depending on the purpose.

[0003] In the prior art, several constructions of hanging ladders are known. For example, the evacuation ladder disclosed in Japanese Patent Laid-Open No. 2006-299800 (Patent Document 1) is known. As shown in Fig. 14, this evacuation ladder has foldable vertical members 2 that connect both ends of two adjacent horizontal bars 1 vertically, guided into the inside of the horizontal bars through slits 1a drilled near the ends of the horizontal bars, and connected to the horizontal bars with connecting pins 4, so that when not in use the vertical members are folded and stored inside the horizontal bars, and when in use the tips of the springs attached to the connecting pins between the vertical members and horizontal bars come into contact with the tips of the extended ends of the lower members 2b of the extended hanging vertical members, which pushes them slightly back inward, so that the vertical members can be reliably and easily folded inward when the ladder is put away after use. The escape ladder in Patent Document 1 does not have a handrail or other member at the top that users can hold onto with their hands.

[0004] For example, a hanging ladder for work at an excavation trench is known, as disclosed in Japanese Patent Laid-Open No. 2012-255275 (Patent Document 2). As shown in Fig. 15, the hanging ladder for work at an excavation trench in Patent Document 2 is a ladder 10 that is used by hanging it from the top end of the excavation trench at the work site, and has a structure in which each rung 1 can be tilted relative to the vertical rungs 2, and can be changed between a use state 1L in which each rung 1 extends in a direction perpendicular to the vertical rungs 2, and a storage state 1M in which each rung 1 is folded in the same direction as the vertical rungs 2, and in the storage state 1M, the protrusion of the rungs 1 can be reduced. The hanging ladder for work at excavation trench sites in Patent Document 2 is structured with a handrail body 6a at the top for the convenience of workers.

[0005] Next, for example, a telescopic ladder is disclosed in JP 2019-173466 A (Patent Document 3). As shown in Fig. 16, the telescopic ladder of Patent Document 3 is a ladder 10 used in work sites such as manholes. The ladder base members 10-1, each of which has a pair of tubular support columns and a rung between them, are connected sequentially and slidably in the axial direction of the tubular support columns. The ladder base members 10-1 are nested and sequentially connected to each other in a telescopic manner. The ladder base members 10-1 can be slidably stored in a retracted state and extended in an extended use state. The ladder base members 10-1 can also be slidably extended. The ladder further includes a handrail 15, which is also extendable relative to the topmost ladder base member 10-1.

[0006] Such hanging ladders require various structures and features depending on the application, but generally they require the following features: The first feature is that it is compact and highly portable when stored. It must be extendable, and when stored (not in use), it must be compact and not bulky, making it easy to store and keep. It must also be lightweight and highly portable when taken out and carried. The second feature is that it is easy to set up when in use. Simply by hanging it from the hanging point, it can be easily extended and ready to use. The third feature is strength and stability during use. When hung from the suspension point and set up, the structure must be strong enough to firmly support the weight of the user, and it must also be convenient to use, such as not swinging during use and being easy to place the feet on the crosspiece. The fourth feature is that it is easy to return the device to its stored state after use. After using it by hanging it from a hanging point, it is necessary to return it to its stored state, but it is preferable that this retrieval operation be easy. The fifth feature is safety. When a ladder user is ascending or descending near the upper rungs, if there is nothing to hold on to, it is difficult to shift weight, so it would be more convenient if there was something like a handrail to hold onto, but generally there are no handrails around where the ladder is hung. This fifth feature, safety, is the same whether it is a hanging ladder that hangs from the bottom up or a hanging ladder that hangs from the top down.

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-315640 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-255275 [Patent Document 3] Japanese Patent Application Laid-Open No. 2019-173466 Summary of the Invention [Problem to be solved by the invention]

[0008] Here, among the above-mentioned suspension ladders, the degree of demand for the above-listed features differs between work suspension ladders and evacuation suspension ladders. Since the primary purpose of an evacuation ladder is to provide evacuation in emergencies such as fires, the second and third features are the most important, with the first and fourth features being of lower priority. However, while the second and third features above remain important for work ladders, the first, fourth, and fifth features also become important in terms of work efficiency.

[0009] The escape ladder for installation on a building's balcony or the like disclosed in the aforementioned Patent Document 1, JP 2006-299800 A, satisfies the first characteristic of being compact and highly portable when stored, and the second characteristic of being easy to set up when used, but lacks the third characteristic of stability and convenience when used. The ladder tends to sway overall, and the rungs have small surface area, making it difficult to place feet on the rungs when hung along a wall. Furthermore, while some ingenuity has been put into the fourth characteristic of making it easy to return the ladder to its stored state after use, it is still not easy to do. Generally, escape ladders do not satisfy the third and fourth characteristics. Furthermore, there is no handrail above the top rung for users to grab, so the fifth characteristic is not satisfied.

[0010] Next, the hanging ladder for use at excavation trench work sites disclosed in Patent Document 2, JP 2012-255275 A, satisfies the second, third, and fifth features described above, but is not extendable in the longitudinal direction. In other words, because it does not extend in the longitudinal direction, it does not satisfy the first and fourth features, and must be brought to the site and used at its original length, and then removed and collected at that length after use. While this is sufficient for sites such as excavation trenches where the height to be climbed is about 1 to 2 meters, it has the problem of being unable to be used at sites where the climb is more than 3 meters, such as manholes (more than 10 meters in deep ones), or on building evacuation balconies.

[0011] Next, Patent Document 3, JP 2019-173466 A, satisfies all of the first to fifth features and is an excellent work ladder. It is also highly rated for being equipped with an extendable handrail body 15. Here, since the user steps on the rung 12 near the top of the ladder body and passes beside the handrail body 15 to ascend or descend, the handrail body 15 is a cylindrical or rod-shaped body that is independent on the left and right, and it is not possible to provide a rung that connects the left and right handrail bodies. In other words, the left and right are independent. Therefore, if the handrail body 15 itself is simply made slidable relative to the ladder body and made telescopic, care must be taken to ensure the stability of the locking mechanism. In the case of a locking mechanism in the ladder basic member 10-1, the left and right tubular support bodies 11 are connected by the cross bars 12, so rotation around the support axis relative to the lower ladder basic member 10-1 is not possible.When the ladder basic member 10-1 is extended or contracted in the vertical direction, the relative movement between the upper and lower ladder basic members 10-1 is only in the vertical direction, and there is little play around the support axis, making it stable. Furthermore, the locking mechanism in the handrail body 15 also allows relative movement of the top ladder basic member 10-1 only in the vertical direction. That is, in Patent Document 3, JP 2019-173466 A, the insertion pin is assumed to be cylindrical and the insertion hole is assumed to be a circular hole of approximately the same diameter, and when the handrail body expands and contracts and slides upward until they are in a position facing each other, the insertion pin is aligned so that it can reliably fit into the insertion hole.

[0012] As described above, the height and extension state of the extended handrail body are fixed in Patent Document 3. However, conditions at work sites such as manholes vary, and it may be preferable to be able to adjust the height of the extended handrail body or adjust its rotation state around the horizontal. Inventor Takashi Teramoto came up with the idea that by allowing the handrail body to slide freely against the top ladder basic member not only in the vertical direction but also horizontally, it would be possible to adjust the height of the extended handrail body and its rotational state horizontally. The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an extendable ladder with extendable handrails that can be easily extended to a position higher than the uppermost horizontal rail by sliding and extending the handrails, and that improves the freedom of the extension state of the handrails, allowing for multiple extension states. [Means for solving the problem]

[0013] In order to achieve the above object, the telescopic ladder with telescopic handrail of the present invention has as its basic unit a pair of tubular support bodies arranged parallel to each other at a predetermined interval and a ladder base member having a rung provided between the tubular support bodies, the ladder base members being sequentially connected to each other in a slidable manner in a nested state in the axial direction of the tubular support bodies, a telescopic ladder main body having a retracted stored state in which the ladder base member is slidably stored and an extended use state in which the ladder base member is slidably extended, a telescopic ladder body having only one tubular body on either the left or right side, or two tubular bodies on the left and right that are independent tubular bodies, and which is slidably connected to the tubular support body of the ladder base member at the top of the ladder main body in a nested state in the axial direction of the tube, and having a retracted stored state in which it is slidably stored and an extended use state in which it is slidably extended, and a telescopic handrail body having a retracted stored state in which it is slidably stored and an extended use state in which it is slidably extended, and a pair of ladder base members on the current and lower steps, or a pair of ladder base members on the handrail body and the ladder base member and an unlocking mechanism which is triggered by an external operation to release the locked state of the locking mechanism and bring the ladder base members of the current and lower steps into an unlocked state in which they can slide together or the handrail body and the ladder base member, wherein the locking mechanism comprises a biasing elastic body incorporated in the ladder base member of each step, an insertion pin which is biased by the biasing elastic body and protrudes, and an insertion hole drilled in the tubular support body or the tubular body of the handrail body, and the insertion pin fits into the insertion hole, and the locking mechanism between the handrail body and the ladder base member at the top step is characterized in that the handrail body is configured to be slidable in the vertical direction and rotatable horizontally relative to the tubular support body of the ladder base member at the top step. The basic structure allows the handrail to move in two directions, vertically and horizontally, resulting in a structure that allows for three-dimensional changes. The handrail can be easily extended and extended to a position higher than the upper horizontal rail, and the degree of freedom in the extension state of the handrail is improved.

[0014] In the above basic configuration, it is preferable that a part of the cylindrical body of the handrail body is provided with a handrail body erected on the wall surface of the cylindrical body. With the above configuration, if there is a handhold body erected on the wall surface of the cylindrical body of the handrail body, it becomes easier for the worker to grasp the rotation position of the handrail body around the support axis. Also, if there is only the cylindrical body, it may be difficult for the worker to grasp the handrail body and rotate it around the support axis because it would slip, but by moving the handrail body while grasping the handhold body protruding from the surface of the cylindrical body, it becomes possible to freely operate both the sliding extension movement and the horizontal rotation movement.

[0015] Here, in the above basic configuration, the locking mechanism between the handrail body and the ladder basic member at the top step may have a structure in which a plurality of insertion holes are provided in the handrail body around the horizontal periphery. With the above-mentioned measures, the handrail body can be extended in multiple ways horizontally. For example, if the cylindrical body of the handrail body is configured with four insertion holes at 90-degree intervals, there will be four insertion holes at 90-degree intervals into which the insertion pins fit, and four possible extension states can be achieved horizontally. In particular, if a handrail body to be grasped is configured to protrude from part of the handrail body, the protruding angle of the handrail body can be selected from four different states.

[0016] Next, in the above basic configuration, in the locking mechanism between the handrail body and the ladder basic member at the top step, there may be a structure in which multiple insertion holes are provided in the handrail body and the heights of the drilling points of each insertion hole are different. The above-mentioned measures allow the handrail body to be extended at multiple heights. For example, if the cylindrical body of the handrail body has four insertion holes, each with a different height, there are four vertical positions: height 1, height 2, height 3, and height 4, resulting in four extended positions for the handrail body.

[0017] In the above basic configuration, it is also possible to combine the insertion holes so that they are drilled in a plurality of different positions horizontally and in different positions in the height direction. With the above-mentioned innovations, for example, when it is slid at an angle of 0 degrees, the insertion pin and insertion hole will fit together at height 1; when it is slid at an angle of 90 degrees, the insertion pin and insertion hole will fit together at height 2; when it is slid at an angle of 180 degrees, the insertion pin and insertion hole will fit together at height 3; and when it is slid at an angle of 270 degrees, the insertion pin and insertion hole will fit together at height 4, so that when the handrail body is extended, there are multiple heights and multiple horizontal positions to choose from.

[0018] Next, in the above basic configuration, the locking mechanism of the handrail body can be configured so that the insertion hole has the horizontal hole and a vertical hole of a width sufficient to accommodate the diameter of the insertion pin arranged upward from the horizontal hole. The above-mentioned innovations ensure a wide range in which the insertion pin fits into the insertion hole due to the sliding extension of the handrail body, ensuring that the insertion pin fits securely into the insertion hole and improving work efficiency.

[0019] Furthermore, in the locking mechanism of the handrail body, the insertion hole is configured to have the horizontal hole and a vertical hole that is connected to the horizontal hole and is provided upward to receive the diameter of the insertion pin. For example, it is an L-shaped insertion hole with a vertical hole provided at the end of the horizontal hole. The above device allows the insertion pin fitted into the insertion hole to be securely fixed. In other words, the insertion pin fitted into the horizontal insertion hole of the L-shaped insertion hole is still rotatable about the support shaft at this stage and is not fixed, but if the worker rotates the handrail body until it can no longer move around the support shaft, the end of the L-shaped insertion hole will hit the vertical hole, and the insertion pin will enter vertically and be securely fixed. As the handrail body extends upward, first the insertion pin fits into the horizontal hole of the L-shaped insertion hole, at which point the upward extension stops, and as the handrail body continues to rotate around the support shaft, the insertion pin fits into the vertical hole of the L-shaped insertion hole, and then it moves along the final vertical hole, in this case downward, until the insertion pin and L-shaped insertion hole settle into a stable position. In other words, as the handrail body extends upward, once the insertion pin fits into the L-shaped insertion hole it is rotated around the support shaft, and finally it is moved downward in the direction of gravity by the length of the vertical hole to fully lock it. While, as in the past, perfect alignment was required to fit a cylindrical insertion pin into a circular insertion hole, by making the insertion hole L-shaped it is possible to easily and reliably achieve the locked state.

[0020] Next, the locking mechanism preferably has the following configuration. The locking mechanism for each step other than the top step has the elastic spring and the insertion pin installed in the cross bar, and the insertion hole is drilled into the outer wall surface of the tubular support body of the ladder basic member.When the ladder basic member slides up and down and the insertion hole comes to a position opposite the insertion pin, the insertion pin is inserted from the cross bar into the insertion hole of the tubular support body, thereby entering the locked state, and the insertion pin is removed from the insertion hole by the unlocking mechanism, thereby entering the unlocked state. Furthermore, the locking mechanism between the handrail body and the topmost ladder basic member is preferably structured so that the elastic spring and the insertion pin are installed between the inner wall surface of the cylindrical support body and the outer wall surface of the handrail body, the insertion hole is drilled in the outer wall surface of the handrail body, and when the handrail body slides up and down and rotates horizontally and the insertion hole comes to a position opposite the insertion pin, the insertion pin is inserted into the insertion hole to enter the locked state, and the unlocking mechanism removes the insertion pin from its inserted state in the insertion hole of the handrail body to enter the unlocked state. With the above configuration, it is possible to easily switch between the locked and unlocked states of the locking mechanisms between the handrail body and the top ladder basic member, and between the ladder basic members below the top ladder basic member.

[0021] Next, in the above basic configuration, it is preferable that the ladder body is provided with multiple projections, and that one or more of the tubular support bodies or cross bars of the ladder body are provided with projection body attachment portions for attaching the projections to the side of the ladder body that is leaned against the work site, opposite the side from the user's climbing surface, so that the projections can be attached to the tubular support bodies or cross bars of the ladder body in the extended state. With the above-mentioned innovations, when used at a work site such as a manhole, if the telescopic ladder with telescopic handrail is too close to the wall of the work site, there will not be enough space for the worker to place their feet on the rungs. However, by providing a prong, a distance equal to the length of the prong can be reliably maintained between the wall of the work site and the telescopic ladder with telescopic handrail, making it easier for the worker to climb up and down.

[0022] Furthermore, the length of the prongs can be adjusted. It is preferable that the length of each prong is adjusted according to the mounting position on the ladder body. If the tips of the prongs are connected to form a virtual plane, when the ladder is placed against a work wall at an actual work site, the entire ladder can be placed at a predetermined angle, and in this state, the tips of each prong will abut against the wall at the work site, resulting in a stable position. [Effects of the Invention]

[0023] According to the telescoping ladder with telescoping handrail of the present invention, the handrail body can freely slide and extend and rotate horizontally, increasing the freedom of movement of the handrail body, and multiple locking states can be achieved by fitting the insertion pin from the top cross bar into the insertion hole of the handrail body. In particular, by providing multiple insertion holes around the horizontal axis of the cylindrical body of the handrail body, the horizontal axis of the handrail body can be in multiple states when locked, and by providing multiple drilling positions for the insertion holes in the handrail body, the height of the handrail body can be in multiple states when locked.Furthermore, multiple states can be created by combining the horizontal axis and the height of the handrail body. If the insertion hole is an L-shaped hole with a horizontal hole and a vertical hole, and the horizontal hole of the L-shaped insertion hole is provided with an insertion hole, the sliding extension of the handrail body can ensure a wide range in which the insertion pin can fit into the insertion hole, and by further rotating it to fit the insertion pin from the horizontal hole into the vertical hole, it can be reliably locked. In addition, by providing the projections, a distance equal to the length of the projections can be reliably maintained between the wall of the work site and the telescopic ladder with telescopic handrails, making it easier for workers to climb up and down. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram showing a schematic configuration example of an extension ladder with extension handrails 100 according to a first embodiment of the present invention. FIG. [Figure 2] 10 is a diagram showing an example of a configuration in which a handrail body 150 has a plurality of insertion holes 152 arranged around the horizontal direction. [Figure 3] FIG. 10 is a diagram showing an example of a configuration in which a handrail body 150 has a plurality of insertion holes 152 arranged around the horizontal direction, each of which has a different height. [Figure 4] 1 is a diagram showing an outline of the operation of the locking mechanism 130 and the unlocking mechanism 140 of each rung of the ladder body 102. FIG. [Figure 5] This is a diagram showing an outline of the operation of the locking mechanism 130 and the unlocking mechanism 140 of each rung of the ladder body 102 when extended. [Figure 6] This is a diagram showing an outline of the operation of the locking mechanism 130 and the unlocking mechanism 140 of each rung of the ladder body 102 when it is retracted. [Figure 7] FIG. 10 is a diagram (part 1) for explaining the locking operation when the insertion hole 152 of the telescopic ladder with telescopic handrail 100a according to the second embodiment is so-called L-shaped. [Figure 8] FIG. 10 is a diagram (part 2) for explaining the locking operation when the insertion hole 152 of the telescopic ladder with telescopic handrail 100a according to the second embodiment is a so-called L-shaped one. [Figure 9]FIG. 10 is a diagram (part 1) for explaining the operation of unlocking the telescopic ladder with telescopic handrail 100a according to the second embodiment when the insertion hole 152 is so-called L-shaped. [Figure 10] FIG. 10 is a diagram (part 2) for explaining the operation of unlocking the telescopic ladder with telescopic handrail 100a according to the second embodiment when the insertion hole 152 is so-called L-shaped. [Figure 11] FIG. 10 is a diagram (part 1) showing an extension ladder with extension handrails 100b according to a third embodiment. [Figure 12] FIG. 10 is a diagram showing an extension ladder with extension handrails 100b according to a third embodiment (part 2). [Figure 13] FIG. 10 is a diagram showing a state in which an extension ladder with extension handrails 100b according to a third embodiment is leaned against a wall surface at a work site. [Figure 14] FIG. 1 is a diagram showing an evacuation ladder to be installed on a balcony or the like of a building, which is disclosed in Japanese Patent Application Laid-Open No. 2006-299800 (Patent Document 1). [Figure 15] FIG. 1 is a diagram showing a suspension ladder for use at a work site in an excavation trench, disclosed in Japanese Patent Application Laid-Open No. 2012-255275 (Patent Document 2). [Figure 16] This is a diagram showing the telescopic ladder disclosed in Japanese Patent Application Laid-Open No. 2019-173466 (Patent Document 3). BEST MODE FOR CARRYING OUT THE INVENTION

[0025] Hereinafter, an embodiment of the telescoping ladder with telescoping handrail of the present invention will be described with reference to the drawings. It goes without saying that the scope of the present invention is not limited to the specific shapes, designs, numbers, angles, etc. shown in the following examples. The first embodiment is a configuration example in which an extendable handrail body is applied. Example 2 is another example of a configuration in which an extendable handrail body is applied. Example 3 is a configuration example in which, together with an extendable handrail body, a projection body is applied to the back side of the ascending and descending surface of an extendable ladder with extendable handrails (the side facing the wall of the work site). Example 1

[0026] FIG. 1 is a diagram schematically illustrating a configuration example of an extension ladder with extension handrails 100 according to a first embodiment of the present invention. Figure 1 shows a front view (the surface from which workers ascend and descend) and a side view of the telescopic ladder with telescopic handrails 100 in the extended state, a front view of the telescopic ladder with telescopic handrails 100 in the contracted state, and a view of the ladder basic member 101. The configuration example of the telescoping ladder with telescoping handrail 100 of the first embodiment is an example of a hanging ladder that extends downward and unfolds, but in principle it can also be applied to a hanging ladder that extends upward and unfolds. In this configuration example, the basic unit ladder basic member 101 is made up of eight steps, and in terms of the number of rungs, including the lowest one, there are nine steps. The telescoping ladder with telescoping handrail 100 of the present invention is equipped with a ladder body 102 and a handrail body 150, which are made up of multiple ladder basic members 101 as basic units that are successively combined so that they can slide up and down, and the ladder as a whole is telescoping. 1, the ladder basic member 101 is configured to include a pair of left and right cylindrical support bodies 110, a crosspiece 120 provided between the cylindrical support bodies 110, a locking mechanism 130, a lock-release mechanism 140, and a handrail body 150. The ladder basic member 101 is configured to include a crosspiece at the bottom, but it can also be configured without a crosspiece.

[0027] The length of the telescopic ladder with telescopic handrail 100 is not limited, but if the depth of the work site is fixed, such as a manhole, for example, the length of the telescopic ladder with telescopic handrail 100 in its extended state is preferably a length appropriate for the depth of the work site, such that it can reach the bottom of the work site in its extended state, the top step of the ladder body 102 is close to the ground at the work site, and the handrail body 150 can be extended to a position higher than the ground at the work site.

[0028] Each component will be described below. The cylindrical support bodies 110 are a pair of support bodies arranged parallel to each other with a predetermined gap between them, as shown in Fig. 1. They are preferably made of a lightweight metal such as aluminum that has high structural strength. Each ladder base member 101 needs to have a certain degree of rigidity and strength. This is because the ladder base member 101 needs to have the mechanical strength to support workers ascending and descending as a ladder at the work site. In addition, since workers may ascend and descend while carrying some weight, the ladder base member 101 needs to be able to withstand that weight. The length of the cylindrical support body 110 for each ladder basic member 101 is not particularly limited, but may be any length that is appropriate for the stride length of a person when ascending or descending one step at a time. The top ladder basic member 101 has a tubular support body 110 that is longer than the other members, and in addition to the original horizontal crosspiece 120 (lower), two dummy horizontal crosspieces 121 (upper) are provided. As shown in the extended and deployed state in Figure 1, the height at which the dummy horizontal bars 121 are installed is set to match the spacing between the horizontal bars 120 of the other rows, so that the spacing between the top horizontal bar 120 and the dummy horizontal bar 121 is approximately equal to the spacing between the horizontal bars 120 of the other rows. In the topmost ladder basic member 101, because the tubular support body 110 is long, there is space for the tubular support body 110 above the dummy rung 121. In this example, as shown in FIG. 1, the locking mechanism 130-1 and the unlocking mechanism 140-1 for the handrail body 150 are installed in that space. The reason for this is that if the locking mechanism 130-1 and the unlocking mechanism 140-1 for the handrail body 150 were installed at the position of the dummy rung 121, the handrail body 150 would slide up to that height, which could cause it to collide with the ladder basic member next from the top. This would force the handrail body 150 to be shortened, which would prevent the handrail body 150 from being long enough. Therefore, to ensure a space further up for installing the locking mechanism 130 and the unlocking mechanism 140 for the handrail body 150, the tubular support body 110 of the topmost ladder basic member 101 is lengthened.

[0029] The rung 120 is a horizontal member provided between the tubular support bodies 110, and is the part on which the worker places his / her feet when ascending or descending. The rung 120 corresponds to one rung of the ladder 100. In this example, the rung 120 is provided to connect the upper ends of the tubular support bodies 110 of the ladder base members 101. As will be described later, the rung 120 contains a locking mechanism 130 and a lock / unlocking mechanism 140 for the insertion hole 133 of the ladder base member 101 of the lower rung. This will be described in more detail later. The horizontal crosspiece 120 is preferably made of a lightweight metal such as aluminum, which has high structural strength. The horizontal crosspiece 120 needs to have a certain degree of rigidity and strength. This is because it needs the mechanical strength to support the worker ascending and descending. In addition, since the worker may ascend and descend while carrying a somewhat heavy load, the horizontal crosspiece 120 needs to be able to withstand that load. The horizontal length of the horizontal beam 120 is not particularly limited, but if it is intended for workers to climb up and down one at a time, it needs to be at least as long as the waist width of a person. As described above, the uppermost horizontal crosspiece 121 simply functions as a horizontal crosspiece, and does not include the locking mechanism 130-1 or the lock / unlock mechanism 140-1 for the insertion hole 152 of the handrail body 150 installed inside.

[0030] Next, the ladder basic member 101 is formed by a pair of hollow cylindrical support bodies 110 on the left and right and a cross bar 120 connecting them, and this cross bar 120 contains a locking mechanism 130 and an unlocking mechanism 140 for the insertion hole 133 of the lower ladder basic member 101. The sliding between the ladder basic members 101 will now be described. As shown in Figure 1, each ladder base member 101 is arranged so that the diameter of the cylindrical portion of their tubular support bodies 110 gradually decreases from the top ladder base member 101 to the bottom ladder base member 101, and they are nested and connected sequentially so as to be slidable in the cylindrical axial direction of the tubular support bodies 110. In other words, the cylindrical portion of the cylindrical support body 110 of the lower ladder base member 101 directly below it is one size smaller than the cylindrical support body 110 of the ladder base member 101 of that stage, and they have a nested structure that can be extended and retracted. The cylindrical portion of the cylindrical support body 110 of the ladder base member 101 of a given rung can slide in and out relative to the cylindrical portion of the cylindrical support body 110 of the ladder base member 101 of the lower rung, and is extended when pulled downward, and contracted when pushed upward. When all of the ladder base members 101 of each rung slide to the contracted state, the entire ladder 100 is in the contracted, stored state, and when all of the ladder base members 101 of each rung slide to the extended state, the entire ladder 100 is also in the extended state.

[0031] An extension structure is also provided between the handrail body 150 and the top ladder basic member 101, so that the handrail body 150 extends upward from the top ladder basic member 101 to enter an extended state, and also retracts downward to enter a shortened state. Here, the left handrail body 150L and the right handrail body 150R are independent of each other, and each is structured to be able to freely rotate horizontally and slide vertically relative to the top ladder base member 101, providing a high degree of freedom of movement. If the left handrail body 150L and the right handrail body 150R were interconnected, they would only be able to slide upward while maintaining the same height, and would not be able to rotate horizontally. In the present invention, the left handrail body 150L and the right handrail body 150R are independent of each other, and the handrail body 150 is structured to be able to slide vertically and rotate horizontally relative to the tubular support column 110 of the top ladder base member 101. In other words, the handrail body 150 can move up and down and horizontally, and has a structure that allows for three-dimensional changes. The handrail body 150 can be easily extended and deployed to a position higher than the ladder body 102, and the degree of freedom in the extension state of the handrail body is improved.

[0032] FIG. 2 is a diagram showing an example of a handrail body 150 having a cylindrical body 151, insertion holes 152, handhold bodies 153, and reference marks 154, in which the insertion holes 152 are arranged in a plurality around the horizontal direction. The handrail body 150 may be one on either the left or right side, or a pair on each side may be provided. Each is independent, and one handrail body 150 is a single cylindrical body. In this example, there are a pair of handrail bodies 150 on each side. A handrail body 153 that can be grasped by a worker is provided on part of the wall surface of the cylindrical body 151. This handrail body 153 allows the worker to grasp while working, and furthermore, the angle of the handrail body 150 makes it easy to grasp the rotational position around the axis of the cylindrical support body 110.

[0033] 2, a donut-shaped locking mechanism 130-1 and a lock releasing mechanism 140-1 for the handrail body 150 are provided inside the cylindrical support body 110 of the top ladder basic member 101 that supports the handrail body 150. In this configuration example, a donut-shaped lid body 111 is also provided at the upper end of the cylindrical support body 110 of the top ladder basic member 101.

[0034] The bottom of Figure 2(a) shows a simplified vertical cross-sectional view of the donut-shaped locking mechanism 130-1 and unlocking mechanism 140-1 for the handrail body 150. The donut-shaped locking mechanism 130-1 has its mechanical components concentrated on the right side (the front side of Figure 1) in this example. The handrail body 150 slides in the central space of the donut-shaped locking mechanism 130-1. The locking mechanism 130-1 is embedded inside the donut shape, and like the locking mechanism 130 described below, it is equipped with an insertion pin 131 and an elastic biasing body 132, and is biased to project toward the inner wall surface. The handrail body 150 has an insertion hole 152, and when the handrail body 150 slides and the insertion hole 152 comes to a position facing the insertion pin 131, the biasing force causes the insertion pin 131 to project and fit into the insertion hole 152. On the other hand, like the unlocking mechanism 140 described later, the unlocking mechanism 140-1 has a wire connected to the insertion pin 131, and by pulling the wire, the insertion pin 131 is retracted and the lock can be released.

[0035] Next, the locking operation of the locking mechanism 130-1 with respect to the handrail body 150 and the unlocking operation of the unlocking mechanism 140-1 will be described. 2, there are multiple insertion holes 152 (four at 90-degree rotational angle intervals in this example), the handrail body 150 is free to move horizontally and also slide up and down, and the insertion pin 131 of the locking mechanism 130-1 of the ladder basic member 101 at the top fits into one of the multiple insertion holes 152 depending on the rotation angle of the handrail body 150. The insertion pin 131 is located in a position protruding from the right side of the cylindrical body 151 of the handrail body 150L in the figure.

[0036] Figure 2(a) shows the engagement with the insertion pin 131 when the handrail body 150L is positioned at a rotation angle of 0 degrees, i.e., a reference angle. The insertion holes 152 corresponding to a rotation angle of 0 degrees are opposed and are positioned to face the insertion pin 131 of the locking mechanism 130-1. In this state, the handrail body 153 is parallel to the rung 120 of the ladder body 102 (toward the back in the figure). The reference mark 154, which is provided to make the rotation angle easy to understand, faces the front. Figure 2(b) shows the engagement with the insertion pin 131 when the handrail body 150L has rotated 90 degrees, that is, rotated 90 degrees from a reference angle. The insertion hole 152 corresponding to a rotation angle of 90 degrees is positioned opposite the insertion pin 131 of the locking mechanism 130-1. In this state, the handrail body 153 has rotated 90 degrees compared to Figure 2(a) and is now on the front side (right side in the figure) of the ladder body 102. A reference mark 154, which is provided to make the rotation angle easy to understand, faces the front side. Figure 2(c) shows the engagement with the insertion pin 131 when the handrail body 150L has rotated 180 degrees, that is, rotated 180 degrees from a reference angle. The insertion hole 152 corresponding to a rotation angle of 180 degrees is positioned opposite the insertion pin 131 of the locking mechanism 130-1. In this state, the handrail body 153 has rotated 180 degrees compared to Figure 2(a) and is now facing outward from the ladder body 102 (toward the viewer in the figure). The reference mark 154, which is provided to make the rotation angle easy to understand, faces outward (to the left in the figure). In FIG. 2, there is also a state in which the handrail body 150L is rotated by another 90 degrees after FIG. 2(c) to a rotation angle of 270 degrees, but the description thereof is omitted here. As shown in FIG. 2, the handrail body 150L has a plurality of rotation angles around the horizontal direction, and there are a plurality of variations in the lock state of the handrail body 150.

[0037] Next, Figure 3 shows an example of a configuration in which a handrail body 150 is configured with a cylindrical body 151, an insertion hole 152, a handhold body 153, and a reference marker 154, and there are multiple insertion holes 152 arranged horizontally, each at a different height. As shown in Figure 3, there are multiple insertion holes 152 (four in this example, at rotational angle intervals of 90 degrees), each at a different height, and the handrail body 150 can move freely horizontally and also slide freely up and down, so that the insertion pin 131 of the locking mechanism 130 of the ladder basic member 101 at the top fits into one of the multiple insertion holes 152 at different heights depending on the rotational angle of the handrail body 150. In Figure 3, the insertion pin 131 of the locking mechanism 130-1 is positioned so as to protrude from the right side of the cylindrical body 151 of the handrail body 150L in the figure.

[0038] Figure 3(a) shows the engagement with the insertion pin 131 when the handrail body 150L is positioned at a rotation angle of 0 degrees, i.e., a reference angle. The insertion hole 152 corresponding to a rotation angle of 0 degrees is positioned opposite the insertion pin 131 of the locking mechanism 130-1. In this state, the handrail body 153 is parallel to the rung 120 of the ladder body 102 and faces toward the center (right side in the figure). The reference mark 154, which is provided to make the rotation angle easy to understand, faces toward the center (right side in the figure). In this example, the insertion hole 152 corresponding to a rotation angle of 0 degrees is drilled at the lowest position, and if the rotation angle of the handrail body 150L is adjusted to this rotation angle and then slid upward, the handrail body 150L will continue to slide upward until it hits the insertion hole 152 drilled at the lowest position, and as shown in Figure 3(a), when it hits the insertion hole 152, the insertion pin 131 will fit into the insertion hole 152 and be locked. It can be seen that the handrail body 150L has slid to the highest position.

[0039] Next, Figure 3(b) shows the engagement with the insertion pin 131 when the handrail body 150L has rotated 90 degrees, that is, rotated 90 degrees from a reference angle. An insertion hole 152 corresponding to a rotation angle of 90 degrees faces the rung and is positioned to face the insertion pin 131 of the locking mechanism 130-1. In this state, the handrail body 153 has rotated 90 degrees compared to Figure 2(a) and is facing the outside of the ladder body 102 (toward the front in the figure). A reference mark 154, which is provided to make the rotation angle easy to understand, faces the front. In this example, the insertion hole 152, which corresponds to a rotation angle of 90 degrees, is drilled at the second lowest position, and if the rotation angle of the handrail body 150L is adjusted so that the rotation angle is 90 degrees and then slid upward, the handrail body 150L will continue to slide upward until it hits the insertion hole 152 drilled at the second lowest position, and as shown in Figure 3(b), when it hits the insertion hole 152, the insertion pin 131 will fit into the insertion hole 152 and be locked. The handrail body 150L will slide to the second highest position, and it can be seen that the handrail body 152 is facing forward in the figure.

[0040] Next, Figure 3(c) shows the engagement with the insertion pin 131 when the handrail body 150L has rotated 180 degrees, that is, rotated 180 degrees from a reference angle. The insertion hole 152 corresponding to a rotation angle of 180 degrees faces the locking mechanism 130-1 and is positioned to face the insertion pin 131 that protrudes from the horizontal rail due to the biasing force. In this state, the handhold body 153 has rotated 180 degrees compared to Figure 3(a) and is facing the back side of the ladder body 102 (left side in the figure). The reference mark 154, which is provided to make the rotation angle easy to understand, faces outward (left side in the figure). In this example, the insertion hole 152, which has a rotation angle of 180 degrees, is drilled at the third lowest position, and if the rotation angle of the handrail body 150L is adjusted so that the rotation angle is 180 degrees and then slid upward, the handrail body 150L will continue to slide upward until it hits the insertion hole 152 drilled at the third lowest position, and as shown in Figure 3(c), when it hits the insertion hole 152, the insertion pin 131 will fit into the insertion hole 152 and lock. It can be seen that the handrail body 150L has slid to the third highest position, and the handhold body 153 is facing left in the figure.

[0041] As shown in Figure 3, the handrail body 150L has multiple rotation angles in the horizontal direction and multiple rotation angles in the vertical direction, which means that there are multiple variations in the locking state of the handrail body 150 in the horizontal direction and multiple rotation angles in the vertical direction.

[0042] As described above, the handrail body 150 and the top basic ladder member 101 slide vertically, and are locked by the locking mechanism 130 through the engagement of the insertion pin 131 with the insertion hole 152, and are locked in the extended state. Similarly, the basic ladder members of each step also slide vertically, and are locked by the locking mechanism 130 through the engagement of the insertion pin 131 with the insertion hole 133, and are locked in the extended state. Below, the operation of the locking mechanism 130 and the unlocking mechanism 140 installed in the rung 120 of the ladder base member 101 will be outlined in detail.

[0043] Figure 4 is a diagram that clearly shows the extension movement of the basic ladder member 101, the stop by locking, and the contraction movement by unlocking in an example configuration in which a ``wire-type locking mechanism type'' is applied, in which the operating lever of the lock release mechanism is incorporated into the front of the crossbar and protrudes, and is linked to the movement of the insertion pin of the locking mechanism. Figure 4(a) shows a state in which the locking mechanism 130 is unlocked and the tubular support body 110 of the lower ladder basic member 101 extends and unfolds from the tubular support body 110 of the upper ladder basic member 101. Figure 4(b) shows the state in which the locking mechanism 130 is activated and locked. The biasing force causes the insertion pin 131 of the locking mechanism 130 located inside the rung 120 of the upper ladder basic member 101 to protrude into the insertion hole 131 of the tubular support body 110 of the lower ladder basic member 101, and the two are locked together, stopping extension. Figure 4(c) shows the state in which the unlocking mechanism 140 has been activated and the lock has been released. The unlocking mechanism 140 returns the insertion pin 131 of the locking mechanism 130 located in the rung 120 of the upper ladder base member 101 against the biasing force from the insertion hole 131 of the tubular support body 110 of the lower ladder base member 101, and the two are no longer engaged, thereby releasing the lock and allowing the ladder to contract.

[0044] As shown in Fig. 4 above, operating levers 141 protrude from the left and right sides of the surface of crosspiece 120, and grooves are provided for sliding operating levers 141 left and right, with operating levers 141 moving along these grooves. As shown in Fig. 4(b), when operating lever 141 slides outward, locking mechanism 130, which will be described later, moves outward and locks. As shown in Fig. 4(c), when operating lever 141 slides toward the center, locking mechanism 130, which will be described later, moves toward the center and releases the lock. The operation of the locking mechanism 130 will be examined in detail with respect to the extension and locking stop of the basic ladder member 101 in Figures 4(a) and 4(b). The operation of the unlocking mechanism 140 will be examined in detail with respect to the unlocking and contraction of the basic ladder member 101 in Figures 4(b) and 4(c).

[0045] FIG. 5 is a diagram showing a mechanism by which each stage is locked by a wire locking mechanism 130 when deployed and extended. FIG. 6 is a diagram showing how the wire-type lock release mechanism 140 of each stage is unlocked when the stage is retracted. The locking mechanism 130 is a locking mechanism that temporarily locks the sliding of the ladder base members 101 at the connection points between the ladder base members 101 of each rung when the ladder is in the extended use state. Figure 3 is a diagram explaining how the wire-type locking mechanism 130 of each rung is activated to lock the ladder.

[0046] 5 shows a portion of the tubular support body 110 facing the left end of the horizontal beam 120, with a portion shown in cross section to make the internal structure easier to understand. The diameter of the tubular portion of the tubular support body 110 gradually decreases as it goes down, so that the tubular support body 110 in the next lower tier fits inside the tubular support body 110 in the upper tier in a telescopic manner. Although not shown, a similar structure that is symmetrical to that shown in FIG. 5 is provided at the right end of the horizontal beam 120.

[0047] As shown in FIG. 5, in the configuration example of the first embodiment, the lock mechanism 130 is configured to include an insertion pin 131, an elastic biasing body 132, and an insertion hole 133. 5, an insertion pin 131 and an elastic biasing body 132 that are biased so as to be able to protrude are provided inside the left end of the horizontal crosspiece 120, and an insertion hole 133 is formed in a part of the opposing cylindrical support body 110. In this way, the insertion pin 131 is pressed against the wall surface until it reaches the position of the insertion hole 133, and is kept biased to the left, and when it reaches the position of the insertion hole 133, it is formed so as to protrude and be able to be inserted.

[0048] As shown in Figure 5(a), when the ladder base member 101 is unfolded and rises, and the tip of the insertion pin 131 reaches the insertion hole 133, as shown in Figure 5(b), the insertion pin 131 protrudes due to the biasing force of the biasing elastic body 132 and fits into the insertion hole 133. Therefore, as shown in Figure 5(b), when the insertion pin 131 comes to a position where the insertion hole 133 is located, the insertion pin 131 protrudes due to the biasing force of the biasing elastic body 132, and as shown in Figure 5(c), the tip of the insertion pin 131 fits into the insertion hole 133, and the ladder base member 101 is fixed so that it cannot slide when in the extended use state.

[0049] Figure 5 shows the movement of only one rung, but as the ladder basic members 101 of each rung of the ladder 100 are unfolded, the rungs 120 of each rung are successively locked by the locking mechanism 130 shown in Figure 5, and the ladder is placed in an extended use state. Here, Figure 5 explains the extension and locking of the ladder basic members 101, but if the insertion hole 133 in Figure 5 is replaced with the insertion hole 152 shown in Figures 2 and 3, the extension and locking of the handrail body 150 and the top ladder basic member 101 is the same.

[0050] Next, the operation of the lock release mechanism 140 will be described in detail. FIG. 6 is a diagram showing how the wire-type lock release mechanism 140 of each stage is unlocked when the stage is retracted. Until just before the ladder 100 begins to be retrieved, the insertion pin 131 is kept pressed into the insertion hole 133 of the left-hand cylindrical support body 110 by the elastic spring 132, as shown in Figure 6(a), and is locked.

[0051] 6(b), when the lock lever is pulled toward the center (right side in the figure), the interlocking fitting pin 131 moves toward the center (right side in the figure). When the fitting pin 131 comes out of the fitting hole 133, the locked state of the lock mechanism 130 is released.

[0052] Next, when the locking mechanism 130 is unlocked by the unlocking mechanism 140, the tubular support bodies 110 become able to slide against each other, as shown in Figure 6(c), and the tubular support body 110 of the unlocked lower ladder basic member 101 slides upward and shortens. The above is the operation of the locking mechanism 130 and the unlocking mechanism 140 for each stage.

[0053] The operation of this locking mechanism 130 and unlocking mechanism 140 causes the ladder unit bodies 101 of each rung to slide against each other, thereby extending and shortening the ladder unit bodies 101, and also causes the handrail body 150 and the top ladder basic unit 101 to slide against each other, thereby extending and shortening the ladder unit bodies 101. Here, Figure 6 explains the unlocking and shortening operation between the ladder basic members 101, but if the insertion hole 133 in Figure 6 is replaced with the insertion hole 152 shown in Figures 2 and 3, the unlocking and shortening operation between the handrail body 150 and the top ladder basic member 101 is the same. Example 2

[0054] As a second embodiment, a configuration example will be described in which an insertion hole 152a of a handrail body 150 is formed with an insertion hole having a shape different from that shown in FIGS. 2 and 3 of the first embodiment. In this embodiment 2, when the handrail body 150a is in the contracted state, it is inserted into the tubular support body 110 of the top ladder basic member 101, and can slide up and down until it is locked by the locking mechanism 130, and can rotate around the support axis.

[0055] 7 and 8 are diagrams simply showing the relationship and movement between the handrail body 150 and the insertion pin 131 of the locking mechanism 130-1 of the top ladder base unit 101 when extended and unfolded. A simple configuration of the handrail body 150a according to the second embodiment is as shown in Figure 7. Only the parts relevant to the explanation are shown in the figure, and other parts are omitted from the illustration. The position of the handrail body 150a in Figure 7 is the position when viewed from the center of the ladder body 102. Therefore, the insertion pin 131 is drawn as a circle with a cylindrical cross section. The locking mechanism 130-1 is drawn as a rectangular frame. As shown in Figure 7, the handrail body 150a of Example 2 has a structure including a cylindrical body 151, an insertion hole 152a, and a handrail body 153 that can be grasped by an operator and is provided on a part of the wall surface of the cylindrical body 151. This handrail 153 makes it easy to grasp the rotational position of the tubular support 110 of the top ladder basic member 101 of the handrail body 150 around the support shaft. In this example, as shown in Figure 5(a), the basic contracted state is when the handrail 153 is parallel to the rung 120. The recommended basic operation is to pull it up from this stored state.

[0056] The operation of the locking mechanism of the handrail body 150a will be described below. In the second embodiment, the insertion hole 152a is a so-called L-shaped hole. That is, the insertion hole 152a is provided with a horizontal hole 1521 that is elongated horizontally in the horizontal direction on the wall surface of the cylindrical body 161 and has a width larger than the diameter of the insertion pin 131 of the uppermost locking mechanism, and a vertical hole 1522 that is connected to the horizontal hole and that receives the diameter of the insertion pin 131 provided upward.

[0057] The handrail body 150a is slidably inserted in a nested manner in the axial direction of the tube into the tubular support body 110 of the ladder basic member 101 at the top of the ladder body 102, and has a retracted storage state in which it is slidably stored, and an extended use state in which it is slidably extended. In Figure 7, part of the state in which it is stored inside the ladder body 102 is shown with dotted lines. Note that the insertion hole 152a itself is stored inside the top ladder base unit 101 and is not visible from the outside, so it should actually be drawn with dotted lines, but it is drawn with solid lines for ease of understanding. In addition, the insertion pin 131 of the top ladder base unit 101 is also inside the locking mechanism 130-1 for the handrail body, but it is drawn with solid lines for ease of understanding. Only the frame of the locking mechanism 130-1 for the handrail body is simply drawn. Although not shown in Figure 7(a), similar to Figures 2 and 3, the insertion pin 131 is biased by a biasing elastic body 132, and in the state of Figure 7(a) it is fitted against the wall surface of the cylindrical body 151 of the handrail body 150 without protruding, but when it faces the insertion hole 152a, the insertion pin 131 protrudes (towards the back of the figure) due to the biasing force and enters the insertion hole 152a, the principle itself being the same as in Figure 5. In the state shown in FIG. 7(a), the handrail body 153 of the handrail body 150 is parallel to the ladder body 102 (toward the viewer in the figure).

[0058] As shown in the transition from Figure 7(a) to Figure 7(b), the handrail bodies 150a can be raised independently. During the raising, the insertion pins 131 abut against the cylindrical bodies 151 of the handrail bodies 150a, and the biasing force is maintained. As shown in Figure 7(b), when the handrail body 150a rises and reaches a predetermined position where the insertion hole 152 of the handrail body 150a is provided, the insertion pin 131 is pushed out into the insertion hole 152a, and in conjunction with this, the operating lever 141 slides outward and locks.

[0059] Here, fitting hole 152 is so-called L-shaped, and horizontal hole 1521 is wide, so that even with some play, fitting pin 131-2 can be reliably captured in horizontal hole 1521. In other words, if the fitting hole is circular, inserting a circular pin of approximately the same diameter into a circular hole of approximately the same diameter may cause play and misalignment, resulting in friction between the two and preventing fitting pin 131 from protruding properly. However, with the configuration of Example 2, horizontal hole 1521 is wide, so that fitting pin 131 can be reliably captured in horizontal hole 1521. 7(a) and 7(b) illustrate the locking operation when the insertion hole 152a is so-called L-shaped. When the handrail body 150a slides upward, the insertion pin 131 of the lock mechanism 130-1 faces the wide horizontal hole 1521 reliably, and the biasing elastic body 132 causes the insertion pin 131 to fit into the wide horizontal hole 1521.

[0060] Next, as shown in Figures 7(b) and 7(c), the operator rotates the handrail body 150a. In this example, the insertion pin 131 itself does not move, but the handrail body 150a rotates outward along the horizontal hole 1521 of the L-shaped insertion hole 152a. In other words, the handrail body 153, which is parallel to the ladder body 102, rotates toward the front of the ladder body 102. The operator continues to rotate the handrail body 150 without stopping it midway until the insertion pin 131 reaches the other end of the horizontal hole 1521. In this example, the handrail body 150a is rotated by approximately 90 degrees. The provision of the handhold body 153 allows the operator to easily recognize the rotational state of the handrail body 150a. Next, as shown in FIG. 7(c), when the handrail body 150a is rotated and the insertion pin 131 reaches the other end of the horizontal hole 1521, a vertical hole 1522 continues upward from the other end of the horizontal hole 1521.

[0061] Figure 8(a) shows the operation after Figure 7(c). Figure 8(a) and Figure 7(c) are in the same state. Next, as shown in Figure 8(b), the handrail body 150 moves downward by its own weight or with the assistance of the operator by the length of the vertical hole 1522. In other words, the insertion pin 131 itself does not move, but the handrail body 150 moves downward, that is, the handrail body 150a moves until the insertion pin 131 reaches the upper end of the vertical hole 1522 along the vertical hole 1522. In the state shown in Figure 8(b), the handrail body 150 is stabilized in this state by its own weight, and unless an operator lifts it by hand, it can no longer slide up or down or rotate horizontally, and is in a stable locked state. When the handrail body 150a is in the extended state, i.e., the state shown in Figure 8(b), the handrail body 153 becomes a member that can be grasped by the worker when using the telescopic ladder with telescopic handrail 100 in the extended state.

[0062] Next, the operation of unlocking the handrail body 150a will be described. Basically, the flow is the opposite of that shown in FIGS. 9 and 10 are diagrams simply showing the relationship and movement between the handrail body 150 and the insertion pin 131 of the top ladder base unit 101 when they are retracted and stored. 9(a), the handrail body 150a is moved upward. At this time, the insertion pin 131 remains protruding from inside, but the handrail body 150a can be moved upward along the vertical hole 1522 of the insertion hole 152, and the worker pulls up the handrail body 150a until the insertion pin 131 reaches the bottom end of the vertical hole 1521. 9(a) to 9(b), the handrail body 150 is rotated inward (to the left in the figure) until the insertion pin 131 reaches the end of the horizontal hole 1521. As a guideline, the handrail body 153 is rotated inward until it is parallel to the horizontal rail 120 (not shown) (toward the front in the figure).

[0063] 10(a) shows the state after rotation to the left in FIG. 9(b). In other words, the handhold body 153 is parallel to the horizontal rail 120 (not shown) (toward the viewer in the drawing). Here, the lock release mechanism 140-1 is operated to pull back the insertion pin 131 and remove it from the insertion hole 152a. The unlocking mechanism 140-1 operates on the same principle as that explained in the shortening of the ladder base unit 101 of each rung shown in Figure 6. In other words, the mechanism and operation itself for releasing the locked state of the locking mechanism 130 in response to an external operation and allowing the handrail body 150a to slide may be the same as those shown in Figure 6. An explanation will be omitted here. 4(c), pulling the wire from the outside triggers the interlocking insertion pin 131 to move toward the center (to the right in the figure). When the insertion pin 131 comes out of the insertion hole 152a, the locked state of the locking mechanism 130 is released. Finally, as shown in FIG. 10(b), the handrail body 150 slides and is housed inside the cylindrical support body 110 of the top ladder basic member 101. Example 3

[0064] Example 3 is an example in which a projection is applied to an extension ladder with an extension handrail. Hereinafter, the rear side of the ascending / descending surface of the telescoping ladder with telescoping handrail 100b (the side facing the wall of the work site) will be simply referred to as the rear side.

[0065] FIG. 11 is a diagram showing an extension ladder with extension handrails 100b according to the third embodiment. In the telescoping ladder with telescoping handrail 100b according to the third embodiment, the ladder body 102 and the handrail body 150 may be the same as those in the first and second embodiments. Figure 11(a) is a diagram of the extended state, in which the ladder body 102 is deployed in an extended state and the handrail body 150 is also extended. Note that the extended state diagram of Figure 1 of Example 1 is a diagram in which the display surface is the front side, but Figure 11(a) is a diagram in which the display surface is the back side.

[0066] The telescoping ladder with telescoping handrail 100b according to the third embodiment is equipped with a plurality of projecting members 160 each having a predetermined length. These projecting members 160 ensure a distance between the ladder body 102 and the wall of the work site. A worker climbs up and down by stepping on the rungs 120, but if a distance is not maintained between the rungs 120 and the wall of the work site, it will be difficult to climb up and down. Therefore, by attaching a plurality of projecting members 160 each having a predetermined length, the distance is ensured.

[0067] Here, the projection attachment portion for attaching the projection 160 may be provided on a part of the rear surface of the cylindrical support 110, or may be provided on a part of the rear surface of the cross rail. In the example of Figure 11, a projection body attachment portion (not shown) is provided on a portion of the horizontal crosspiece 120. A pair of projection body attachment portions (not shown) are provided on the left and right sides of the rear surface of the horizontal crosspiece 120. The number of projection bodies is not limited, but in this example, they are provided in three locations: on the upper, middle, and lower sides. As shown in Figure 11, projection bodies 160 are attached to these projection body attachment portions (not shown). In this example, a pair of upper projection bodies 160UR and 160UL, a pair of middle projection bodies 160MR and 160ML, and a pair of lower projection bodies 160LR and 160LL are provided.

[0068] In the example of Figure 12, a projection body attachment portion (not shown) is provided on a part of the cylindrical support body 110. A pair of projection body attachment portions (not shown) are provided on the left and right sides of the back surface of the cylindrical support body 110. Similarly, the number of projection bodies is not limited, but in this example, they are provided in three locations: on the upper side, the center side, and the lower side. As shown in Figure 12, projection bodies 160 are attached to these projection body attachment portions (not shown). In this example, a pair of upper projection bodies 160UR and 160UL, a pair of middle projection bodies 160MR and 160ML, and a pair of lower projection bodies 160LR and 160LL are provided.

[0069] Here, the structure for attaching the projection 160 to the projection attachment portion is not limited. For example, there is a screw structure, in which a female screw is provided on the projection body attachment portion and a male screw is provided on the base of the projection body 160, and the two are screwed together to connect them. For example, there is a fitting structure, in which the diameter of the base of the projection 160 matches the diameter of the hole in the projection attachment part, and the projection 160 is pushed in and fitted to connect. Other connection methods can also be used as long as they can securely attach the projections 160.

[0070] One way to do this is to adjust the length of the projection 160 depending on the installation location. As mentioned above, the projection 160 is a component that ensures a distance between the wall of the work site and the extension ladder with telescoping handrails 100b, but the installation state will be more stable if the extension ladder with telescoping handrails 100b is leaned against the wall at a slight angle rather than facing the wall upright.

[0071] Figure 13 shows the state in which the telescoping ladder with telescoping handrail 100b is leaned against the wall surface of a work site. As shown in Figure 13, the length of the prongs 160 increases as the attachment point moves downward. In Figures 11 and 12, the line of the expected work wall is shown by a dotted line, and the length of each prong 160 has been adjusted to fit this expected work wall surface, so that when the tips of the prongs 160 are connected, they will overlap the line of the expected work wall surface. In Figure 13, the upright work wall surface corresponds to the assumed work wall surface in Figures 11 and 12. Therefore, the extension ladder with extension handrails 100b is placed at a predetermined angle, and in this state the projections 160 come into contact with the work wall surface, making it easier to stabilize the installation state of the extension ladder with extension handrails 100b.

[0072] While the preferred embodiment of the present invention has been shown and described, it will be understood that various changes can be made therein without departing from the spirit and scope of the invention, which is therefore to be limited only by the appended claims. [Industrial Applicability]

[0073] The extendable ladder of the present invention can be widely used as a ladder, such as a ladder used in work places such as manholes and underground sites, and as a ladder for evacuation from train cars. [Explanation of symbols]

[0074] 100 ladders 101 Ladder basic components 102 Ladder body 110 Cylindrical support body 120 Horizontal Bar 121 Fixed crosspiece 130,130-1 Locking mechanism 131 Inset pin 132 biasing elastic body 133 Insertion hole 140,140-1 Unlocking mechanism 141 Operating lever 150 Handrail body 151 Cylindrical body 152 Insertion hole 153 Clue Body 154 Reference Mark 160 Projection body

Claims

1. The ladder body has a basic unit consisting of a pair of tubular support bodies arranged parallel to each other at a predetermined interval and a ladder base member having a crosspiece provided between the tubular support bodies, the ladder base members being sequentially connected to each other in a nested manner so as to be slidable in the axial direction of the tubular support bodies, and has a retractable ladder body having a contracted storage state in which the ladder base members are slidably stored and an extended use state in which the ladder base members are slidably extended; a telescopic handrail body comprising only one cylindrical body on either the left or right side, or two cylindrical bodies on the left and right sides that are independent of each other, and which is slidably connected in a nested state in the axial direction of the cylindrical support body of the ladder basic member at the top of the ladder body, and which has a slidably stored contracted storage state and a slidably extended extended use state; A locking mechanism that temporarily locks the ladder base members of the current and lower steps into a locked state when the ladder base members or the handrail body and the ladder base member slide against each other to reach the extended use state; A lock release mechanism is provided which releases the locked state of the lock mechanism in response to an external operation, and sets the ladder base members of the current and lower steps to an unlocked state in which they can slide relative to each other or the handrail body and the ladder base member, The locking mechanism is configured to include a biasing elastic body incorporated in the ladder base member of each step, an insertion pin that is biased by the biasing elastic body and protrudes, and an insertion hole drilled in the cylindrical support body or the cylindrical body of the handrail body, and the insertion pin fits into the insertion hole, In the lock mechanism at the top stage, the insertion hole includes a horizontal hole and a vertical hole provided upward from the horizontal hole and having a width sufficient to receive the diameter of the insertion pin, An extendable ladder with extendable handrails, characterized in that the locking mechanism between the handrail body and the ladder basic member at the top level is structured so that the handrail body can slide up and down and rotate horizontally relative to the tubular support body of the ladder basic member at the top level.

2. An extension ladder with an extension handrail as described in claim 1, characterized in that in the locking mechanism of the handrail body, the insertion hole has a horizontal hole in the horizontal direction of the wall surface of the cylindrical body whose width is greater than the diameter of the insertion pin of the uppermost locking mechanism.

3. An extension ladder with an extension handrail as described in claim 1, characterized in that in the locking mechanism between the handrail body and the ladder basic member at the top step, multiple insertion holes are provided in the handrail body around the horizontal axis.

4. An extension ladder with an extendable handrail as described in claim 1, characterized in that in the locking mechanism between the handrail body and the ladder basic member at the top step, multiple insertion holes are provided in the handrail body, and the heights of the drilling points of each insertion hole are different.

5. The telescopic ladder with telescopic handrails described in claim 1, characterized in that in the locking mechanism between the handrail body and the ladder basic member at the top, multiple insertion holes are provided in the handrail body, and the horizontal rotation angle and height are different at each drilling point.

6. The telescopic ladder with telescopic handrails described in claim 1, characterized in that a part of the cylindrical body of the handrail body is provided with a handrail body that is erected on the wall surface of the cylindrical body, and by grasping the handrail body, the sliding extension movement and the horizontal rotation movement of the handrail body can be freely controlled.

7. The locking mechanism for each step other than the top step has a spring-loaded elastic body and an insertion pin installed in the crossbar, and the insertion hole is drilled in the outer wall surface of the tubular support body of the ladder base member; when the ladder base member slides up and down and the insertion hole comes to a position opposite the insertion pin, the insertion pin is inserted from the crossbar into the insertion hole of the tubular support body, thereby entering the locked state; and the insertion pin is removed from the insertion hole by the unlocking mechanism, thereby entering the unlocked state.

2. The telescopic ladder with telescopic handrails according to claim 1, characterized in that the locking mechanism between the handrail body and the top ladder basic member is configured such that the elastic spring and the insertion pin are installed between the inner wall surface of the cylindrical support body and the outer wall surface of the handrail body, the insertion hole is drilled in the outer wall surface of the handrail body, and when the handrail body slides up and down and rotates horizontally so that the insertion hole comes to a position opposite the insertion pin, the insertion pin is inserted into the insertion hole to enter the locked state, and the lock release mechanism removes the insertion pin from its inserted state in the insertion hole of the handrail body to enter the unlocked state.

8. A plurality of projections is provided, The tubular support body or the rung of one or more of the ladder bodies is provided with a protrusion attachment portion for attaching the protrusion to the side of the ladder body that is leaned against the work site on the side opposite to the side where the user climbs up and down, 8. An extension ladder with an extension handrail according to claim 1, wherein the projections can be attached to the cylindrical support columns or cross bars of the ladder body when it is in an extended state.

9. 9. An extension ladder with an extension handrail according to claim 8, wherein the length of each of the projections is adjusted according to the attachment position of each projection on the ladder body.

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