Movable safety ladder

Abstract

The invention relates to a movable safety ladder which adopts the advantages of A-shaped ladders and platform ladders and makes up for the disadvantages of the A-shaped ladders and the platform ladders. The movable safety ladder comprises: a ladder body (10) having a first frame (20) and a second frame (30) which are spaced apart from each other relative to a hinge axis of an upper portion of the ladder body (10) when the portable safety ladder is unfolded, maintain an A shape, and fully fold around the hinge axis when the portable safety ladder is folded; and an upper safety handrail (40) provided at an upper portion of the ladder main body (10) in a ring shape to prevent a worker standing on a work platform (15) of the ladder main body (10) from falling, in which the upper safety handrail (40) is provided at an upper portion of a pair of support members (50) assembled to rise and fall with respect to the first frame (20) to prevent the worker standing on the work platform (15) of the ladder main body (10) from falling. And the second frame (20) is arranged in a rotatable form so as to be completely folded towards the second frame (30) and be in close contact with the second frame (20) when the portable safety ladder is folded.

Description

Technical Field

[0001] The present invention relates to a portable safety ladder that can be folded and transported, and more particularly, to a portable safety ladder that can prevent safety accidents by preventing workers from falling, ladder toppling, and ladder sliding, which are the main causes of accidents involving portable ladders, and can reduce the volume and weight of the ladder, so that the portable safety ladder can be conveniently carried and transported. Background Art

[0002] Portable ladders are widely used in various construction sites, telecommunication construction sites, fruit farms, etc.

[0003] Typically, when working at height, a scaffolding device or an aerial work platform is fixedly installed at the work site and then the work is completed.

[0004] However, when it is difficult to install a scaffold or an aerial work platform due to a narrow work site, or when work needs to be performed while moving, portable ladders are mainly used.

[0005] Figure 1 An example of a ladder as one of conventional portable ladders is shown.

[0006] Figure 1 The illustrated ladder (hereinafter referred to as an "A-type ladder") is configured such that a first frame 20 and a second frame 30 form an A-shape. Each frame has steps 22 or 33 installed horizontally at regular intervals.

[0007] The A-type ladder has the advantages of simple structure, easy folding and easy transportation to the required location.

[0008] However, Figure 1 The A-type ladder shown does not have a separate working platform. Therefore, there is a risk of workers falling during work.

[0009] In addition, since the ladder structure is unstable, there is a high risk of safety accidents due to the ladder's tipping or sliding.

[0010] According to Korean industrial accident statistics, the number of deaths related to ladder accidents in the past five years (2018 to 2022) was 176, and 95% of the accidents were related to portable ladders.

[0011] In order to solve the above-mentioned problems, so-called platform ladders equipped with a working platform on the ladder have been developed and used.

[0012] like Figure 2 As shown, the platform ladder is provided with a working platform 15 having a certain area at the top of the step 22, and is provided with a handrail 18 so that a worker can hold the handrail 18 with his hand and climb up.

[0013] The advantage of a platform ladder is that it is safer than an A-frame ladder by having a safety platform.

[0014] However, Figure 2 The platform ladder shown is not only large and heavy, but also has a non-foldable structure, thereby making it inconvenient to carry and transport the platform ladder.

[0015] As a result, workers at actual construction sites avoid using platform ladders.

[0016] Meanwhile, there are ladders equipped with outriggers among conventional ladders. However, the disadvantage of such ladders is that they can only be used when the floor is flat and a certain amount of space is ensured. Summary of the invention

[0017] Technical issues

[0018] In view of the problems inherent in the prior art, an object of the present invention is to provide a portable safety ladder that adopts the advantages of A-type ladders and platform ladders while compensating for their disadvantages.

[0019] Another object of the present invention is to provide a portable safety ladder capable of maintaining the workability and transportability which are advantages of an A-type ladder while ensuring the safety which is an advantage of a platform ladder.

[0020] Another object of the present invention is to provide a portable safety ladder that can prevent accidents caused by workers losing balance, ladder toppling, and ladder sliding while making it easy to move and store the ladder.

[0021] Another object of the present invention is to provide a portable safety ladder that can minimize its weight while maintaining the advantages of a platform ladder.

[0022] Another object of the present invention is to provide a portable safety ladder that can improve work efficiency during continuous mobile work by making the ladder as light as possible.

[0023] Another object of the present invention is to provide a portable safety ladder which can minimize its volume when folded, making it easy to carry and transport.

[0024] Another object of the present invention is to provide a portable safety ladder that does not require the installation of separate handrails to improve safety when workers move up and down the ladder.

[0025] Another object of the present invention is to provide a portable safety ladder that can prevent workers' feet from falling off a working platform during work and can prevent tools or equipment on the working platform from falling off.

[0026] Another object of the present invention is to provide a portable safety ladder that can improve an existing outrigger structure to ensure that the outrigger is stably supported even when obstacles exist or the space is narrow.

[0027] Means of solving tasks

[0028] In order to achieve these purposes, a portable safety ladder is provided, which includes: a ladder body, the ladder body including a first frame and a second frame, the first frame and the second frame being separated from each other around an upper hinge axis to maintain an A shape when the portable safety ladder is unfolded, and being completely folded around the upper hinge axis when the portable safety ladder is folded; and an upper safety railing, the upper safety railing being arranged in a ring shape at the upper part of the ladder body to prevent workers riding on a working platform of the ladder body from falling, wherein the upper safety railing is arranged above a pair of base members, the base members are assembled to move up and down relative to the first frame, and the upper safety railing is arranged to be swivel type, so that when the portable safety ladder is folded, the upper safety railing is completely folded toward the second frame side and is in close contact with the second frame.

[0029] The upper safety rail may be provided with a cushioning shoulder pad so that the ladder body can be folded and carried on the shoulder.

[0030] Steps may be horizontally provided at regular intervals on the first frame, and struts may be provided on the second frame instead of the steps so that a worker can move up and down only on the first frame side.

[0031] Openings may be formed at regular intervals in the first frame along the vertical direction, openings may be formed at regular intervals in the second frame along the vertical direction, and openings may be formed at regular intervals in the base member along the vertical direction, so that workers can move up and down by grasping the frames through these openings.

[0032] Each of the first frame and the second frame may be bent so as to expand outward from the middle of the entire height.

[0033] A foot stopper plate of a certain height may be provided around the working platform to prevent the worker's feet from leaving the working platform.

[0034] A pair of links may be rotatably disposed at opposite ends of the entrance of the working platform, and the links may be connected to an annular intermediate handrail by an upper hinge, so that when the ladder body is folded, the intermediate handrail rotates downward to allow the working platform to be fully folded.

[0035] Support members may be obliquely provided on both sides of the lower portion of the working platform to support the working platform when the working platform is unfolded.

[0036] A level gauge may be provided in front of the entrance of the working platform to indicate a horizontal state of the portable safety ladder.

[0037] Active outriggers may be provided at both sides of the lower end of each of the first frame and the second frame to stably support the portable safety ladder on the ground, obstacles, or a vertical surface consistent with the terrain and obstacles on the floor.

[0038] Each of the outriggers may include an outrigger leg configured to be folded on both sides of the first frame and the second frame, and a locking portion configured to secure the outrigger leg supported on the ground, an obstacle or a vertical surface.

[0039] The locking portion may include a locking rod and a stopper, the locking rod being arranged so that an end of the locking rod corresponds to an upper surface of the outrigger leg while being rotatably mounted on the ladder body above the outrigger leg, and the locking rod being configured to be folded toward the ladder body together with the outrigger leg, and the stopper being configured to limit rotation of the outrigger leg supported on the ground by fixing the end of the locking rod to the upper surface of the outrigger leg.

[0040] The stopper may be movably mounted at an end of the locking rod, the stopper may be elastically pressed by a return spring so as to frictionally contact with a bottom surface of a locking groove formed along a longitudinal upper surface of the outrigger leg, and when the outrigger leg is extended from the ladder body and supported on the ground, an obstacle or a vertical surface, the stopper may frictionally contact with the bottom surface of the locking groove of the outrigger leg to fix the end of the locking rod to the outrigger leg.

[0041] The outrigger may include two outriggers disposed at both sides of a lower end of the first frame, and the two outriggers may be disposed at right angles with respect to each other.

[0042] The portable safety ladder may also include: a hollow first lower frame, which is arranged below the first frame so that the first frame can be inserted into and removed from the first lower frame; and a hollow second lower frame, which is arranged below the second frame so that the second frame can be inserted into and removed from the second lower frame, wherein the first frame and the second frame can be adjusted in height by the first lower frame and the second lower frame.

[0043] Each of the first frame and the second frame may be provided with a scale display portion for indicating the height of the portable safety ladder when adjusting the height.

[0044] Each of the first lower frame and the second lower frame may be bent obliquely outward at a middle portion thereof.

[0045] The portable safety ladder may further include casters provided at both sides of the lower portion of the second lower frame.

[0046] Effects of the Invention

[0047] The portable safety ladder according to the present invention can have the advantages of the A-type ladder and the platform ladder while compensating for their disadvantages.

[0048] In other words, the portable safety ladder can maintain the workability and transportability which are advantages of the A-type ladder while ensuring the safety which is an advantage of the platform ladder.

[0049] In particular, since safety comparable to that of an existing platform ladder can be ensured, the portable safety ladder can prevent accidents caused by workers losing balance, ladder toppling, and ladder sliding.

[0050] In addition, the portable safety ladder can minimize its volume when folded, making it easy to carry, transport and store.

[0051] Furthermore, since the frame of the portable safety ladder is provided with a plurality of openings, the weight of the portable safety ladder can be reduced, thereby improving the convenience of transportation.

[0052] Furthermore, since a worker can grip the frame using the opening formed in the frame when moving up and down, there is no need to install a separate guardrail on the frame.

[0053] Furthermore, since the supporting member is configured as a lifting type and the upper safety railing is configured as a rotating type, the overall height can be reduced when the portable safety ladder is folded.

[0054] Furthermore, by providing a cushioning shoulder pad at the center of the upper safety rail, a worker can conveniently carry the portable safety ladder on his shoulders when moving a short distance.

[0055] Furthermore, since the working platform is a fully foldable structure, the width can be minimized when the portable safety ladder is folded.

[0056] Furthermore, by providing a foot stopper plate on the edge of the working platform, the worker's feet will not leave the working platform during work, thereby preventing tipping accidents.

[0057] In addition, tools or equipment on the work platform can be prevented from falling.

[0058] Furthermore, by providing a level gauge at the front of the working platform, workers can check the levelness of the working platform when climbing onto the working platform.

[0059] Furthermore, thanks to the active outrigger structure, the portable safety ladder can be stably fixed regardless of the terrain, objects or obstacles on the floor. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a view showing an A-type ladder according to the prior art.

[0061] Figure 2 is a view showing a platform ladder according to the related art.

[0062] Figure 3 is a perspective view of a portable safety ladder according to a first embodiment of the present invention.

[0063] Figure 4 1 and 2 are side and front views showing a safety ladder according to a first embodiment of the present invention in an unfolded state.

[0064] Figure 5 1 and 2 are side and front views showing a safety ladder according to a first embodiment of the present invention in a folded state.

[0065] Figure 6 1 is a view showing a working platform and an upper safety railing of a safety ladder according to a first embodiment of the present invention.

[0066] Figure 7 1 is a view showing an extended state of an outrigger of the safety ladder according to the first embodiment of the present invention.

[0067] Figure 8 1 is a view showing a use state of an outrigger of the safety ladder according to the first embodiment of the present invention.

[0068] Fig. 91 and 2 are a side view and a front view showing a deployed state of a safety ladder according to a second embodiment of the present invention.

[0069] Fig.10 1 and 2 are a side view and a front view showing a folded state of a safety ladder according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0070] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0071] <First Embodiment>

[0072] Figures 3 to 8 A portable safety ladder according to a first embodiment of the present invention is shown.

[0073] The portable safety ladder according to the first embodiment of the present invention includes: a ladder body 10, which includes a first frame 20 and a second frame 30, which are separated from each other around an upper hinge axis to maintain an A shape when the portable safety ladder is unfolded, and are completely folded around the upper hinge axis when the portable safety ladder is folded; and an upper safety railing 40, which is arranged in a ring shape on the upper part of the ladder body 10 to prevent workers riding on the working platform 15 of the ladder body 10 from falling, wherein the upper safety railing 40 is arranged above a pair of base members 50, and the base members are assembled to move up and down relative to the first frame 20.

[0074] The base member 50 is fixed to and released from the first frame 20 by the upper fixing member 52 and the lower fixing member 53 .

[0075] The upper fixing member 52 and the lower fixing member 53 may adopt various fixing means, such as locking pins and clamps.

[0076] In addition, the upper safety railing 40 is provided in a rotation type such that when the portable safety ladder is folded, the upper safety railing 40 is completely folded toward the second frame 30 side and is in close contact with the second frame 30 .

[0077] That is, the upper safety railing 40 according to the present invention is horizontally unfolded toward the first frame 20 side where workers climb on when in use, and is completely folded toward the second frame 30 side in the direction opposite to the direction in which workers climb on when the portable safety ladder is folded.

[0078] Furthermore, the upper safety rail 40 is provided as an integral part with the lifting base member 50 , and when the portable safety ladder is unfolded and folded, the upper safety rail 40 is raised and lowered together with the base member 50 .

[0079] The above structure allows the overall height of the portable safety ladder to be minimized when it is folded.

[0080] The upper safety rail 40 is provided with a cushioning shoulder pad 41 so that the ladder body 10 can be folded and carried on the shoulder.

[0081] The shoulder pad 41 is formed into an arc shape to fit the shoulder area of ​​the human body. Figure 6 shown.

[0082] This allows a worker to transport the portable safety ladder by carrying the shoulder pad 41 on the shoulder after folding the portable safety ladder, thereby reducing the worker's labor intensity.

[0083] Furthermore, in the portable safety ladder according to the present invention, the steps 22 are horizontally provided at regular intervals on the first frame 20, and the pillars 32 are provided on the second frame 30 instead of the steps.

[0084] That is, the portable safety ladder according to the present invention has a structure in which a worker can move up and down only on one side of the portable safety ladder, ie, on the first frame 20 side.

[0085] This essentially prevents two workers from riding on the portable safety ladder at the same time.

[0086] Furthermore, the openings 21 are formed at regular intervals in the vertical direction in the first frame 20 , the openings 31 are formed at regular intervals in the vertical direction in the second frame 30 , and the openings 51 are formed at regular intervals in the vertical direction in the base member 50 .

[0087] In this regard, the openings 21 , 31 , and 51 are formed in the shape of long grooves so that a worker can grasp the frame with his / her hands through the openings.

[0088] In addition, the openings 21 , 31 , and 51 are formed to correspond to the arrangement distance of the pedal 22 .

[0089] With the above structure, a worker can move up and down along the step 22 while grasping the frame through the openings 21 , 31 , and 51 with his / her hands.

[0090] Therefore, there is no need to install a separate handrail on the frame for the safety of workers when moving up and down, and the weight of the frame can be reduced to make the portable safety ladder lighter.

[0091] The frame and base members according to the present invention are preferably made of aluminum, and their surfaces are preferably hard anodized.

[0092] In addition, if Figure 5 As shown, the first frame 20 and the second frame 30 according to the present invention are bent so as to expand outwardly in the middle of the entire height.

[0093] With the above structure, the portable safety ladder can be stably supported on the ground when unfolded.

[0094] In addition, if Figure 6 As shown, the portable safety ladder according to the present invention includes a foot stopper plate 16 disposed at a certain height around the working platform 15 .

[0095] This prevents the worker's feet from being separated from the work platform 15 during aerial work, thereby preventing falling or tipping accidents.

[0096] In addition, if Figure 3 and Figure 4 As shown, the portable safety ladder according to the present invention includes a pair of connecting rods 55, which are rotatably disposed at opposite ends of the entrance of the working platform 15. The connecting rods 55 are connected to the annular middle handrail 54 through an upper hinge 54a.

[0097] With the above structure, when the ladder body 10 is Figure 5 When folded as shown, the middle armrest 54 is rotated downward so that the working platform 15 is completely folded. This allows the width of the portable safety ladder to be minimized when the portable safety ladder is folded.

[0098] In addition, support members 17 are obliquely provided on both sides of the lower portion of the working platform 15 to support the working platform 15 when the working platform 15 is unfolded.

[0099] By means of the supporting member 17 , when a worker steps onto the working platform 15 , the worker can be stably supported.

[0100] In addition, if Figure 6 As shown, the portable safety ladder according to the present invention further includes a level meter 70, which is disposed in front of the entrance of the working platform 15 to indicate the horizontal state of the portable safety ladder.

[0101] By means of the level 70 , a worker can visually check the levelness of the portable safety ladder before stepping onto the working platform 15 .

[0102] like Figure 7 As shown, the portable safety ladder according to the present invention further includes active outriggers 60 on both sides of the lower ends of the first frame 20 and the second frame 30, and the outriggers 60 are fixed to the ground, obstacles or vertical surfaces consistent with the terrain and obstacles on the floor.

[0103] Each outrigger 60 includes an outrigger leg 64 disposed to be folded at both sides of the first frame 20 and the second frame 30 , and a locking portion 66 configured to fix the outrigger leg 64 supported on the ground, an obstacle, or a vertical surface.

[0104] To this end, the locking portion 66 includes: a locking rod 66a, which is arranged so that its end portion corresponds to the upper surface of the outrigger leg 64, and is rotatably mounted on a portion of the ladder body 10 above the outrigger leg 64, and is configured to be folded toward the ladder body 10 together with the outrigger leg 64; and a stopper 66b, which is configured to limit the rotation of the outrigger leg 64 supported on the ground by fixing the end portion of the locking rod 66a to the upper surface of the outrigger leg 64.

[0105] The locking lever 66 a is rotatably mounted on the ladder body 10 so as to have the same folding direction as the outrigger leg 64 , and an end of the locking lever 66 a is configured to correspond to an upper surface of the outrigger leg 64 .

[0106] In particular, it is configured to be received in a locking groove 64 a formed along a longitudinal upper surface of the outrigger leg 64 .

[0107] At this point, since the locking lever 66 a has the same folding direction as the outrigger leg 64 , the locking lever 66 a is folded toward the ladder body 10 together with the outrigger leg 64 .

[0108] The stopper 66b is movably mounted at the end of the locking rod 66a. The stopper 66b thus mounted fixes the end of the locking rod 66a to the outrigger leg 64 while frictionally contacting the bottom surface of the locking groove 64a of the outrigger leg 64.

[0109] In addition, the stopper 66 b is elastically pressed by the return spring 66 c so as to come into frictional contact with the bottom surface of the locking groove 64 a of the outrigger leg 64 .

[0110] When the outrigger leg 64 is extended from the ladder main body 10 and supported on the ground or the like, the elastically pressed stopper 66 b comes into frictional contact with the bottom surface of the locking groove 64 a of the outrigger leg 64 .

[0111] Thus, the end of the locking rod 66 a is fixed to the outrigger leg 64 .

[0112] This enables the locking lever 66a to support the upper surface of the outrigger leg 64. As a result, the outrigger leg 64 can be locked while being supported on the ground or the like.

[0113] In this regard, the locking lever 66 a and the stopper 66 b are configured to move along the locking groove 64 a of the outrigger leg 64 and to frictionally contact the bottom surface of the locking groove 64 a .

[0114] As a result, the outrigger legs 64 can be locked regardless of the extension angle of the outrigger legs 64 .

[0115] like Figure 8As shown, through the structure of the outrigger, the portable safety ladder can be stably supported even when there are obstacles or the space is narrow.

[0116] In particular, the outriggers may be supported on a vertical surface rather than the floor.

[0117] In addition, two outriggers 60 are provided on both sides of the lower end of the first frame 20 .

[0118] In this regard, the two outriggers 60 are preferably arranged at right angles relative to each other, such as Figure 8 shown.

[0119] With the above structure, the portable safety ladder can be supported more stably.

[0120] In the following, reference will be made to Figure 4 and Figure 5 The process of using the portable safety ladder according to the present invention is described.

[0121] First, if Figure 5 As shown, the portable safety ladder in the folded state is unfolded into an A-shape by separating the first frame 20 and the second frame 30 .

[0122] Then, the working platform 15 is also unfolded to stably support the first frame 20 and the second frame 30 .

[0123] Then, the upper safety railing 40 is horizontally deployed toward the first frame 20 on which the workers will board, and then is fixed.

[0124] Next, the upper fixing member 52 and the lower fixing member 53 are released, the base member 50 is lifted upward, and the base member 50 is fixed.

[0125] The outriggers 60 are then deployed and secured to the ground, an obstacle or a vertical surface.

[0126] In this state, the worker climbs up the ladder along the step 22 while gripping the first frame 20 with his / her hands through the opening 21 formed in the first frame 20 .

[0127] At this time, the worker moves his / her upper body to the inside of the upper safety railing 40 and climbs onto the working platform 15 .

[0128] When the work is completed, the worker walks down the ladder while gripping the first frame 20 through the opening 21 , and then releases the fixed state of the upper fixing member 52 and the lower fixing member 53 .

[0129] Then, the base member 50 is lowered to the initial position and fixed, and the outriggers 60 are retracted to the initial position.

[0130] Then, when the first frame 20 and the second frame 30 overlap each other, the working platform 15 is also folded.

[0131] Then, when the upper safety rail 40 is rotated to its initial position (ie, toward the second frame 20 ) and pressed against the second frame 30 , the folding of the portable safety ladder is completed.

[0132] <Second Embodiment>

[0133] Fig. 9 and Fig.10 A portable safety ladder according to a second embodiment of the present invention is shown.

[0134] The portable safety ladder according to the second embodiment of the present invention can adjust the height of the frame in the first embodiment described above and is more convenient for transportation.

[0135] The portable safety ladder according to the second embodiment of the present invention further includes a hollow first lower frame 20b disposed below the first frame 20 so that the first frame can be inserted into and removed from the first lower frame 20b.

[0136] The portable safety ladder further includes a hollow second lower frame 30b disposed below the second frame 30 so that the second frame can be inserted into and removed from the second lower frame 30b.

[0137] In addition, the first lower frame 20 b is provided with a fixing member 20 a for fixing and releasing the first frame 20 , and the second lower frame 30 b is provided with a fixing member 30 a for fixing and releasing the second frame 30 .

[0138] Through the above structure, the heights of the first frame 20 and the second frame 30 can be adjusted.

[0139] In addition, each of the first frame 20 and the second frame 30 is provided with a scale display portion for indicating the height of the portable safety ladder when adjusting the height.

[0140] Each of the first lower frame 20b and the second lower frame 30b is bent obliquely outward at the middle thereof. This enables the portable safety ladder to be stably supported.

[0141] Casters 80 are further provided on both sides of the lower portion of the second lower frame 30b.

[0142] By using the casters 80, the folded portable safety ladder can be conveniently moved on a flat floor surface.

[0143] Since other details are the same as those of the above-mentioned first embodiment, repeated description will be omitted.

[0144] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Various modifications and changes may be made without departing from the scope and spirit of the present invention defined in the claims.

Claims

1. A portable safety ladder, comprising: A ladder body (10), the ladder body comprising a first frame (20) and a second frame (30), the first frame and the second frame being separated from each other around an upper hinge axis to maintain an A-shape when the portable safety ladder is unfolded, and being completely folded around the upper hinge axis when the portable safety ladder is folded; as well as an upper safety railing (40) arranged in a ring shape on the upper part of the ladder body (10) to prevent workers riding on the working platform (15) of the ladder body (10) from falling, wherein the upper safety rail (40) is disposed above a pair of base members (50), the base members being assembled to move up and down relative to the first frame (20), and The upper safety rail (40) is configured as a rotation type, so that when the portable safety ladder is folded, the upper safety rail (40) is completely folded toward the second frame (30) side and is in close contact with the second frame (30).

2. The portable safety ladder according to claim 1, wherein: The upper safety rail (40) is provided with a cushioning shoulder pad (41) so that the ladder body (10) can be folded and carried on the shoulder.

3. The portable safety ladder according to claim 1, wherein: Pedals (22) are horizontally arranged at regular intervals on the first frame (20), and A support column (32) is provided on the second frame (30) instead of the pedal, so that a worker can only move up and down on the side of the first frame (20).

4. The portable safety ladder according to claim 3, wherein: Openings (21) are formed in the first frame (20) at regular intervals in the vertical direction. Openings (31) are formed in the second frame (30) at regular intervals along the vertical direction, and Openings (51) are formed in the base member (50) at regular intervals along the vertical direction so that a worker can move up and down by grasping the frame through the openings.

5. The portable safety ladder according to claim 4, wherein: Each of the first frame (20) and the second frame (30) is bent so as to expand outward from the middle of the entire height.

6. The portable safety ladder according to claim 1, wherein: A foot stopper plate (16) of a certain height is arranged around the working platform (15) to prevent the worker's feet from leaving the working platform (15).

7. The portable safety ladder according to claim 6, wherein: A pair of connecting rods (55) are rotatably arranged at opposite ends of the entrance of the working platform (15), and The connecting rod (55) is connected to the annular intermediate handrail (54) through an upper hinge (54a), so that when the ladder body (10) is folded, the intermediate handrail (54) rotates downward to allow the working platform (15) to be fully folded.

8. The portable safety ladder according to claim 7, wherein: Support members (17) are obliquely arranged on both sides of the lower part of the working platform (15) to support the working platform (15) when the working platform (15) is unfolded.

9. The portable safety ladder according to claim 8, wherein: A level gauge (70) is provided in front of the entrance of the working platform (15) to indicate the horizontal state of the portable safety ladder.

10. The portable safety ladder according to claim 1, wherein: Active outriggers (60) are provided on both sides of the lower end of each of the first frame (20) and the second frame (30) to stably support the portable safety ladder on the ground, obstacles or a vertical surface consistent with the terrain and obstacles on the floor.

11. The portable safety ladder according to claim 10, wherein: Each of the outriggers (60) includes an outrigger leg (64) and a locking portion (66), wherein the outrigger leg is configured to be folded on both sides of the first frame (20) and the second frame (30), and the locking portion is configured to fix the outrigger leg (64) supported on the ground, an obstacle or a vertical surface.

12. The portable safety ladder according to claim 11, wherein: The locking portion (66) includes a locking rod (66a) and a stopper (66b), wherein the locking rod is arranged so that an end of the locking rod corresponds to an upper surface of the outrigger leg (64), and is rotatably mounted on the ladder body (10) above the outrigger leg (64), and the locking rod is configured to be folded toward the ladder body (10) together with the outrigger leg (64), and the stopper is configured to limit the rotation of the outrigger leg (64) supported on the ground by fixing the end of the locking rod (66a) to the upper surface of the outrigger leg (64).

13. The portable safety ladder according to claim 12, wherein: The stopper (66b) is movably mounted at the end of the locking rod (66a), The stopper (66b) is elastically pressed by a return spring (66c) so as to frictionally contact with the bottom surface of a locking groove (64a) formed along the longitudinal upper surface of the outrigger leg (64), and When the outrigger leg (64) is extended from the ladder body (10) and supported on the ground, an obstacle or a vertical surface, the stopper (66b) frictionally contacts the bottom surface of the locking groove (64a) of the outrigger leg (64) to secure the end of the locking rod (66a) to the outrigger leg (64).

14. The portable safety ladder according to claim 13, wherein: The outrigger (60) includes two outriggers (60) disposed on both sides of the lower end of the first frame (20), and The two outriggers (60) are arranged at right angles to each other.

15. The portable safety ladder according to claim 1, further comprising: a hollow first lower frame (20b) disposed below the first frame (20) so that the first frame can be inserted into and removed from the first lower frame (20b); and a hollow second lower frame (30b) disposed below the second frame (30) so that the second frame can be inserted into and removed from the second lower frame (30b), The first frame (20) and the second frame (30) can be adjusted in height by the first lower frame (20b) and the second lower frame (30b).

16. The portable safety ladder according to claim 15, wherein: Each of the first frame (20) and the second frame (30) is provided with a scale display portion for indicating the height of the portable safety ladder when adjusting the height.

17. The portable safety ladder according to claim 15, wherein: Each of the first lower frame (20b) and the second lower frame (30b) is bent obliquely outward at a middle portion thereof.

18. The portable safety ladder according to claim 15, further comprising: Casters (80) are arranged on both sides of the lower part of the second lower frame (30b).

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