Extension ladder

Abstract

The utility model belongs to the technical field of ladders, and particularly relates to an extension ladder, which comprises a ladder main body, the ladder main body comprises a plurality of layers of left ladder pipes and right ladder pipes which are mutually sleeved, the left ladder pipes and the right ladder pipes on the upper layer can be respectively sleeved in the left ladder pipes and the right ladder pipes on the lower layer in sequence, and cross rod pedals are arranged on the left ladder pipes and the right ladder pipes on each layer. The telescopic ladder is simple in structure, and when the telescopic ladder is pulled open, a user can clearly know whether the interior of the telescopic ladder is stably clamped or not.

Description

Technical Field

[0001] The utility model belongs to the technical field of ladders, in particular to a telescopic ladder. Background Art

[0002] Ladders are a common tool for climbing heights. For the convenience of carrying, existing ladders are generally processed into telescopic ladders. They are set up on the principle of a large tube covering a small tube. When needed, each tube can be extended by pulling it apart. Compared with a ladder with a fixed length, the first thing to consider for this type of telescopic ladder is stability and safety. In order to improve safety, telescopic ladders currently on the market usually have plug rods and buttons inside and outside the pedals respectively. A socket is provided on the vertical rod, and the control button drives the plug rod to move. When the plug rod is engaged with the socket, the rod is restricted from moving downward. At this time, the user will not move downward when stepping on the pedal. However, this When using this method, special attention should be paid to whether the insertion rod and the socket are properly engaged. When the user pushes the button to move the insertion rod, since the insertion rod is inside the pedal, the user cannot know how much the insertion rod has moved or whether it is completely engaged. If the foot steps on such an unstable pedal, the weight of the person can easily move the pedal downward. This height difference is particularly likely to cause a person to fall. In particular, when the telescopic ladders on the market are opened, each pedal needs to be repeatedly operated with the button. This mechanical repetition is more likely to make people negligent. Therefore, there is a need for a telescopic ladder that can clearly let the user know whether the internal connection is stable when the telescopic ladder is opened. Summary of the Invention

[0003] The utility model aims to provide a telescopic ladder with a simple structure, which can clearly let the user know whether the internal connection is stable when the telescopic ladder is pulled out.

[0004] The purpose of this utility model is achieved in this way:

[0005] A telescopic ladder comprises a ladder body, wherein the ladder body comprises a plurality of layers of mutually sleeved left ladder tubes and right ladder tubes, wherein the left ladder tube and the right ladder tube of the upper layer can be respectively sleeved in the left ladder tube and the right ladder tube of the lower layer, and each layer of the left ladder tube and the right ladder tube is provided with a crossbar step, and the ends of each layer of the crossbar step are respectively connected to the left ladder tube and the right ladder tube of each layer;

[0006] The crossbar pedal is provided with a locking assembly, and the locking assembly includes a plug rod movably arranged in the crossbar pedal and can abut against the outer wall of the left ladder tube and the right ladder tube, an elastic member at one end connected to the plug rod and a hook member movably connected to the plug rod, the hook member is partially exposed on the lower surface of the crossbar pedal, and the crossbar pedal is provided with a rotation slot, and the hook member is convexly provided with a rotating rod, and the hook member is arranged in the rotating slot through the rotating rod and can rotate around the rotating rod, the upper end of the hook member is connected with the plug rod and can drive the plug rod to move laterally outward or inward through rotation, and the lower end of the hook member is provided with an inserting part, and the upper end of the crossbar pedal is convexly provided with a connecting part, and a slot is provided on the connecting part. When the upper left ladder tube and the right ladder tube move downward, they are sleeved on the lower left ladder tube and When the right ladder tube is in the right ladder tube, the hook piece rotates to drive the insertion part to insert into the slot. At this time, the insertion rod in the lower cross bar pedal abuts against the outer walls of the upper left ladder tube and the right ladder tube and restricts the insertion part from leaving the slot. The lower end of the hook piece is also provided with an abutment portion. After the upper left ladder tube and the right ladder tube move downward, the abutment portion on the hook piece in the upper cross bar pedal abuts against the connecting portion on the lower cross bar pedal, and the upper cross bar pedal continues to move downward. At this time, the connecting portion on the lower cross bar pedal pushes the abutment portion of the upper hook piece to rotate inward. At this time, the hook piece in the upper cross bar pedal rotates around the rotating rod and drives the insertion part to insert into the slot in the connecting portion of the lower cross bar pedal. The insertion rod is moved inward laterally by the rotation of the upper end of the hook piece to squeeze the elastic member.

[0007] The lower ends of the left and right ladder tubes are each provided with a lower insertion hole. When the upper cross bar pedal is pulled upward, the upper left and right ladder tubes move upward. When the lower insertion holes at the lower ends of the upper left and right ladder tubes are at the same horizontal line with the insertion rods in the lower cross bar pedal, the insertion rods in the lower cross bar pedal are released from the restriction and move outward to be inserted into the lower insertion holes. The hook rotates around the rotating rod and drives the insertion part out of the slot. At this time, the upper cross bar pedal can be pulled away from the lower cross bar pedal.

[0008] Furthermore, a clamping portion is provided in the middle of the insertion rod, the diameter of the clamping portion is smaller than the diameter of the two ends of the insertion rod, and a clamping portion is provided at the upper end of the hook piece. The number of the clamping portions is 2, and the two clamping portions are adjacently arranged and clamp the clamping portion.

[0009] Furthermore, a pushing portion is provided on the hook member. When the clamping portion is connected to the clamping portion, the pushing portion abuts against the insertion rod. When the abutting portion on the upper horizontal bar pedal is pushed by the connecting portion on the lower horizontal bar pedal, the hook member rotates with the rotating rod, thereby pushing the insertion rod inward through the pushing portion. At this time, one end of the insertion rod is disengaged from the lower insertion hole.

[0010] Furthermore, a sliding inclined surface is provided at the upper end of the connecting portion, and a sliding surface is provided between the abutting portion and the inserting portion. When the connecting portion on the lower crossbar pedal pushes the abutting portion on the upper hook member to rotate inward, the sliding surface contacts the sliding inclined surface.

[0011] Furthermore, a mounting groove is provided in the crossbar pedal, a mounting seat is provided in the mounting groove, a mounting hole is opened on the mounting seat, the elastic member and one end of the insertion rod are provided in the mounting hole, one end of the elastic member is against the mounting hole, and the other end is in contact with the end of the insertion rod. When the left ladder tube and the right ladder tube move upward and the lower insertion holes on the left ladder tube and the right ladder tube are in the same horizontal line with the insertion rod, the elastic member pushes the insertion rod to move outward and insert into the lower insertion hole. At this time, the upper left ladder tube and the right ladder tube cannot move into the lower left ladder tube and the right ladder tube, and the elastic member is a spring.

[0012] Furthermore, an upper pull rod is provided above the ladder body, and the left ladder tube and the right ladder tube on both sides of the upper pull rod are arranged in the left ladder tube and the right ladder tube on both sides of the lower cross bar pedal. Pulling the upper pull rod upward can drive the left ladder tube and the right ladder tube on both sides of the upper pull rod to move upward, and when the lower insertion holes at the lower ends of the left ladder tube and the right ladder tube on both sides of the upper pull rod are at the same horizontal line with the insertion rod in the lower cross bar pedal, the insertion rod of the lower cross bar pedal moves outward and is inserted into the lower insertion hole.

[0013] Furthermore, a lower bottom rod is provided below the ladder body, and the locking assembly is also provided in the lower bottom rod. The rotating part in the lower bottom rod is manually driven to rotate to drive the insertion rod to move laterally inward. At this time, the insertion rod is disconnected from the lower insertion holes of the left ladder tube and the right ladder tube on the upper layer of the lower rod. At this time, the crossbar pedal on the upper layer can move downward mainly along with the left ladder tube and the right ladder tube on both sides.

[0014] Compared with the prior art, the present invention has the following outstanding and beneficial technical effects:

[0015] The utility model relates to a telescopic ladder. The structure of the previous telescopic ladder is usually that the insertion rod is clamped with the ladder tube to limit the ladder tube from descending. When the user needs to use it, he needs to press the switch of each layer to control the movement of the insertion rod of each layer. Each layer has a left ladder tube and a right ladder tube. The user needs to press the insertion rod on both sides to clamp with the left ladder tube and the right ladder tube respectively. This method requires a lot of operations and it is impossible to know the internal clamping status. If the clamping is not done well, when the user steps on the crossbar pedal, the weight will cause the crossbar pedal to move downward, and the user will fall. If the user moves the insertion rod for a long time and many times, the insertion rod will be offset in the crossbar pedal, and the user may easily fail to insert it. The bottom of the invention believes that the two are already locked, or the elastic member in the crossbar pedal has been squeezed and expanded for a long time, and the elastic force is no longer as strong as before. The user cannot feel the distance the insertion rod has moved, and the insertion rod may only be inserted into the lower insertion hole a little bit. In order to increase safety, the utility model provides a hook member on the insertion rod, and an insertion portion on the hook member, so that the hook member is rotatably connected to the crossbar pedal. When the hook member is rotated by the rotating rod, the insertion portion at the lower end can rotate in an arc direction. The utility model also provides a convex connecting portion on the upper surface of the crossbar pedal, and a slot corresponding to the insertion portion is provided on the connecting portion. When the hook member is rotated, the insertion portion is inserted into the slot as the hook member rotates, and the rod rotates with it. When the upper left and right ladder tubes move upward, the lower ends of the upper left and right ladder tubes are at the same level with the rods in the lower cross-bar pedal. At this time, the rods in the lower cross-bar pedal can be inserted into the lower plug holes, and the hooks on the lower cross-bar pedals can move. The insertion rod rotates and drives the insertion part to disengage the slot on the next cross bar pedal. At this time, the lower cross bar pedal can continue to be pulled upward. The utility model locks the upper cross bar pedal and the lower cross bar pedal layer by layer. Only when the upper cross bar pedal is unlocked can the lower cross bar pedal be pulled upward. If the lower insertion holes at the lower ends of the left ladder tube and the right ladder tube of the upper layer are not at the same level as the insertion rod in the lower cross bar pedal, the insertion part on the lower cross bar pedal will always be unable to move in the slot, and the lower cross bar pedal will be unable to move upward. The user only needs to judge whether he can pull the upper and lower cross bar pedals to judge whether the insertion rod is in the lower insertion hole, which is safer.There is no need to worry about the jamming of a certain layer, and to open the ladder, you only need to pull the top layer open, and the horizontal bar pedals of the lower layer can be selected according to the number of layers to be pulled open according to the needs of the user. There is no need to press each layer, and it is more convenient to pull it open directly at one time. The lower ends of the left and right ladder tubes of the utility model are provided with lower plug holes, and through holes are also provided at the upper ends. When the upper left and right ladder tubes and the lower left and right ladder tubes that are fitted together are pulled apart, the lower plug holes at the lower ends of the upper left and right ladder tubes will be at the same horizontal line as the through holes at the upper ends of the lower left and right ladder tubes and will be inserted by the plug rods in the horizontal bar pedals. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional diagram of the present utility model.

[0017] Figure 2 It is a front view of the utility model.

[0018] Figure 3 It is an exploded view of the utility model.

[0019] Figure 4 It is a stereoscopic diagram of a single-layer left ladder tube, a crossbar pedal, and a right ladder tube of the utility model.

[0020] Figure 5 It is an exploded view of the single-layer left ladder pipe, crossbar pedal and right ladder pipe of the utility model.

[0021] Figure 6 This is one of the schematic diagrams of the crossbar pedal of the present utility model.

[0022] Figure 7 This is the second schematic diagram of the crossbar pedal of the present utility model.

[0023] Figure 8 This is an exploded view of the crossbar pedal of the utility model.

[0024] Figure 9 It is a side view of the locking assembly of the utility model.

[0025] Figure 10 It is a partial structural diagram of the crossbar pedal of the utility model.

[0026] Figure 11 It is a schematic diagram of the connection between the upper crossbar pedal and the lower crossbar pedal of the utility model.

[0027] Figure 12 yes Figure 11 A partial enlarged view of point A in the middle.

[0028] Figure 13 It is a sectional view of the upper pull rod of the utility model.

[0029] Figure 14 It is a schematic diagram of the utility model after folding.

[0030] Figure 15 It is a front view of the utility model after folding.

[0031] The meaning of the numbers in the figure:

[0032] 1-ladder body; 2-left ladder tube; 3-right ladder tube; 4-crossbar pedal; 5-locking assembly; 6-insertion rod; 7-elastic member; 8-hook member; 9-rotation groove; 10-rotation rod; 11-insertion part; 12-connecting part; 13-slot; 14-abutment part; 15-lower insertion hole; 16-clamping part; 17-clamping part; 18-pushing part; 19-sliding inclined surface; 20-sliding surface; 21-mounting groove; 22-mounting seat; 24-upper pull rod; 25-lower bottom rod; 26-observation window. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific embodiments:

[0034] A telescopic ladder includes a ladder body 1, wherein the ladder body 1 includes a plurality of layers of mutually sleeved left ladder tubes 2 and right ladder tubes 3, wherein the left ladder tube 2 and the right ladder tube 3 of the upper layer can be respectively sleeved within the left ladder tube 2 and the right ladder tube 3 of the lower layer, and each layer of the left ladder tube 2 and the right ladder tube 3 is provided with a crossbar pedal 4, and the ends of each layer of the crossbar pedal 4 are respectively connected to the left ladder tube 2 and the right ladder tube 3 of each layer;

[0035] The crossbar pedal 4 is provided with a locking assembly 5, and the locking assembly 5 includes an insertion rod 6 movably arranged in the crossbar pedal 4 and can abut against the outer walls of the left ladder pipe 2 and the right ladder pipe 3, an elastic member 7 connected to the insertion rod 6 at one end, and a hook member 8 movably connected to the insertion rod 6, and the hook member 8 is partially exposed on the lower surface of the crossbar pedal 4. A rotation slot 9 is provided in the crossbar pedal 4, and a rotating rod 10 is convexly provided on the hook member 8. The hook member 8 is arranged in the rotating slot 9 through the rotating rod 10 and can rotate around the rotating rod 10. The upper end of the hook member 8 is connected with the insertion rod 6 and can drive the insertion rod 6 to move laterally outward or inward through rotation. The lower end of the hook member 8 is provided with an insertion portion 11, and the upper end of the crossbar pedal 4 is convexly provided with a connecting portion 12, and a slot 13 is provided on the connecting portion 12. When the upper left ladder pipe 2 and the right ladder pipe 3 move downward, they are sleeved on the lower left ladder pipe 2 and the right ladder pipe 3. When the upper left ladder tube 2 and the right ladder tube 3 are moved downward, the abutting portion 14 on the hook member 8 in the upper crossbar pedal 4 abuts against the connecting portion 12 on the lower crossbar pedal 4, and the upper crossbar pedal 4 continues to move downward. At this time, the connecting portion 12 on the lower crossbar pedal 4 pushes the abutting portion 14 of the upper hook member 8 to rotate inward. At this time, the hook member 8 in the upper crossbar pedal 4 rotates around the rotating rod 10 and drives the insertion portion 11 to insert into the slot 13 in the connecting portion 12 of the lower crossbar pedal 4. The insertion rod 6 is subjected to the rotation of the upper end of the hook member 8 to move inward laterally to squeeze the elastic member 7;

[0036] The lower ends of the left ladder tube 2 and the right ladder tube 3 are both provided with lower insertion holes 15. When the upper cross bar pedal 4 is pulled upward, the upper left ladder tube 2 and the right ladder tube 3 move upward. When the lower insertion holes 15 at the lower ends of the upper left ladder tube 2 and the right ladder tube 3 are at the same horizontal line with the insertion rod 6 in the lower cross bar pedal 4, the insertion rod 6 in the lower cross bar pedal 4 is released from the restriction and moves outward to be inserted into the lower insertion hole 15. The hook part 8 rotates around the rotating rod 10 and drives the insertion part 11 to disengage from the slot 13. At this time, the upper cross bar pedal 4 can be pulled away from the lower cross bar pedal 4.

[0037] The utility model is a telescopic ladder. The structure of the previous telescopic ladder is usually that the insertion rod 6 is connected with the ladder tube to limit the ladder tube from falling. When the user needs to use it, he needs to press the switch of each layer to control the movement of the insertion rod 6 of each layer. Each layer has a left ladder tube 2 and a right ladder tube 3. The user will need to press the insertion rod 6 on both sides to respectively connect with the left ladder tube 2 and the right ladder tube 3. This operation amount is extremely large and it is impossible to know the internal connection status. Once the connection is not good, when the user steps on the crossbar pedal 4, the weight will cause the crossbar pedal 4 to move downward. At this time, the user will fall. If the user moves the insertion rod 6 for a long time and many times, the insertion rod 6 will be offset in the crossbar pedal 4. The user may easily think that the two are connected before they are inserted to the bottom, or the crossbar pedal 4 is not inserted to the bottom. After the elastic member 7 in the pedal 4 is squeezed and expanded for a long time, the elastic force is not as good as before, and the user cannot feel the distance moved by the insertion rod 6. The end of the insertion rod 6 may be inserted into the lower insertion hole 15 only a little bit. In order to increase safety, the present invention provides a hook member 8 on the insertion rod 6, and an insertion portion 11 on the hook member 8, so that the hook member 8 is rotatably connected to the crossbar pedal 4. When the hook member 8 is rotated by the rotating rod 10, the insertion portion 11 at the lower end can rotate in an arc direction. The present invention also provides a convex connecting portion 12 on the upper surface of the crossbar pedal 4, and a slot 13 corresponding to the insertion portion 11 is provided on the connecting portion 12. When the hook member 8 is rotated, the insertion portion 11 is inserted into the slot 13 as the hook member 8 rotates. At this time, the insertion rod 6 moves inward laterally with the rotation. When the left and right ladder tubes 2 and 3 on the upper layer are moved upward, the lower ends of the upper left and right ladder tubes 2 and 3 are at the same horizontal line with the rod 6 in the lower cross-bar pedal 4. At this time, the rod 6 in the lower cross-bar pedal 4 can be inserted into the lower insertion hole 15, and the hook piece 8 on the lower cross-bar pedal 4 can be inserted with the hook piece 8 on the lower cross-bar pedal 4. When the lever 6 is in the unlocked position, the lower crossbar pedal 4 can be pulled upwards.There is no need to worry about the jamming of a certain layer, and to open the ladder, you only need to pull the top layer open, and the crossbar pedal 4 of the lower layer can be selected according to the number of layers to be opened according to the needs of the user, without pressing each layer, and it is more convenient to directly open it at one time. The lower ends of the left and right ladder tubes 2, 3 of the utility model are provided with lower insertion holes 15, and through holes are also provided at the upper ends. When the upper left and right ladder tubes 2, 3 of the upper layer and the lower left and right ladder tubes 2, 3 of the lower layer are pulled apart, the lower insertion holes 15 at the lower ends of the upper left and right ladder tubes 2, 3 will be at the same horizontal line as the through holes at the upper ends of the lower left and right ladder tubes 2, 3 and will be inserted by the insertion rods 6 in the crossbar pedal 4.

[0038] Preferably, a clamping portion 16 is provided in the middle of the insertion rod 6, and the diameter of the clamping portion 16 is smaller than the diameter of the two ends of the insertion rod 6. A clamping portion 17 is provided at the upper end of the hook member 8, and the number of the clamping portions 17 is 2. The two clamping portions 17 are adjacently arranged and clamp the clamping portion 16, so that the clamping portion 16 and the clamping portion 17 are clamped with each other. When the user drives the hook member 8 to rotate, the clamping portion 17 can drive the clamping portion 16 to rotate so that the insertion rod 6 can move laterally.

[0039] Preferably, a pushing portion 18 is further provided on the hook member 8. When the clamping portion 17 is connected to the clamping portion 16, the pushing portion 18 abuts against the insertion rod 6. When the abutting portion 14 on the upper crossbar pedal 4 is pushed by the connecting portion 12 on the lower crossbar pedal 4, the hook member 8 rotates with the rotating rod 10, thereby pushing the insertion rod 6 to move inward through the pushing portion 18. At this time, one end of the insertion rod 6 disengages from the lower insertion hole 15, which is convenient for the user to push the insertion rod 6 to move when driving the hook member 8 to rotate. When the clamping portion 17 is clamped with the clamping portion 16, one side of the pushing portion 18 abuts against the surface generated by the diameter difference between the clamping portion 16 and the insertion rod 6, thereby preventing the user from manually moving the insertion rod 6. When the hook member 8 rotates, the upper end of the hook member 8 rotates backward and naturally pushes the insertion rod 6 to move through the pushing portion 18.

[0040] Preferably, a sliding inclined surface 19 is further provided at the upper end of the connecting portion 12, and a sliding surface 20 is further provided between the abutting portion 14 and the insertion portion 11. When the connecting portion 12 on the lower crossbar pedal 4 pushes the abutting portion 14 on the upper hook member 8 to rotate inward, the sliding surface 20 contacts the sliding inclined surface 19, so that after the connecting portion 12 pushes the abutting portion 14 to rotate, the hook member 8 can rotate smoothly.

[0041] Preferably, a mounting groove 21 is provided in the crossbar pedal 4, a mounting seat 22 is provided in the mounting groove 21, a mounting hole is opened on the mounting seat 22, the elastic member 7 and one end of the plug rod 6 are provided in the mounting hole, one end of the elastic member 7 is against the mounting hole, and the other end is in contact with the end of the plug rod 6. When the left ladder tube 2 and the right ladder tube 3 move upward, the lower insertion holes 15 on the left ladder tube 2 and the right ladder tube 3 are at the same horizontal line as the plug rod 6, the elastic member 7 pushes the plug rod 6 to move outward and insert into the lower insertion hole 15. At this time, the upper left ladder tube 2 and the right ladder tube 3 cannot move into the lower left ladder tube 2 and the right ladder tube 3. The elastic member 7 is a spring. Before the ladder body 1 of the present invention contracts, the ends of the two insertion rods 6 in the crossbar pedal 4 are respectively against the outer walls of the left ladder tube 2 and the right ladder tube 3. When the left ladder tube 2 and the right ladder tube 3 move upward, the lower insertion holes 15 at the lower ends of the left ladder tube 2 and the right ladder tube 3 are at the same horizontal line. At this time, there is space in front of the insertion rod 6, and the elastic member 7 can push the insertion rod 6 outward.

[0042] Preferably, an upper pull rod 24 is provided above the ladder body 1, and the left ladder tube 2 and the right ladder tube 3 on both sides of the upper pull rod 24 are provided in the left ladder tube 2 and the right ladder tube 3 on both sides of the lower crossbar pedal 4. Pulling the upper pull rod 24 upward can drive the left ladder tube 2 and the right ladder tube 3 on both sides of the upper pull rod 24 to move upward. When the lower insertion holes 15 at the lower ends of the left ladder tube 2 and the right ladder tube 3 on both sides of the upper pull rod 24 are at the same horizontal line with the insertion rod 6 in the lower crossbar pedal 4, the insertion rod 6 of the lower crossbar pedal 4 moves outward and inserts into the lower insertion holes 15. When the utility model needs to be opened, the upper pull rod 24 is directly pulled, and the left ladder tube 2 and the right ladder tube 3 on the upper pull rod 24 are upward. At this time, the lower insertion hole 15 will be at the same horizontal line as the insertion rod 6 in the first layer cross bar pedal 4, and the insertion rod 6 in the first layer cross bar pedal 4 is inserted into the lower insertion hole 15. At this time, the insertion rod 6 moves and is inserted into the lower insertion hole 15, driving the hook part 8 to rotate so that the insertion part 11 is out of the slot 13. At this time, the second layer cross bar pedal 4 is not restricted by the first layer cross bar pedal 4 and can continue to be pulled upward.

[0043] When the ladder is lowered, the locking member 12 on the lower crossbar tread 4 is pushed by the connecting portion 12 on the lower crossbar tread 4, thereby driving the hook member 8 to rotate. As the ladder is lowered, the ladder is automatically retracted by gravity or weight, and there is no need to manually unlock the ladder layer by layer.

[0044] Preferably, an observation window 26 is also provided on one side of the crossbar pedal 4, so that the user can clearly observe whether the insertion rod 6 of each layer is in a penetration state with the lower insertion rod 6. When the insertion rod 6 moves inward, the user can see the upper end of the rotated hook 8 from the observation window 26. When the insertion rod 6 is inserted into the lower insertion hole 15, the user can only see the insertion rod 6 from the observation window 26.

[0045] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A telescopic ladder, comprising a ladder body (1), characterized in that: The ladder body (1) comprises a plurality of layers of mutually sleeved left ladder tubes (2) and right ladder tubes (3); the left ladder tube (2) and the right ladder tube (3) of the upper layer can be sleeved in turn in the left ladder tube (2) and the right ladder tube (3) of the lower layer; a crossbar pedal (4) is provided on each layer of the left ladder tube (2) and the right ladder tube (3); and both ends of the crossbar pedal (4) of each layer are respectively connected to the left ladder tube (2) and the right ladder tube (3) of each layer; A locking assembly (5) is provided in the crossbar pedal (4), and the locking assembly (5) includes an insertion rod (6) movably provided in the crossbar pedal (4) and capable of abutting against the outer walls of the left ladder tube (2) and the right ladder tube (3), an elastic member (7) connected to the insertion rod (6) at one end, and a hook member (8) movably connected to the insertion rod (6), wherein the hook member (8) is partially exposed on the lower surface of the crossbar pedal (4), a rotation groove (9) is provided in the crossbar pedal (4), and a rotation rod (10) is protruded on the hook member (8). The hook member (8) is arranged in the rotating groove (9) through the rotating rod (10) and can rotate around the rotating rod (10). The upper end of the hook member (8) is connected to the insertion rod (6) and can drive the insertion rod (6) to move horizontally outward or inward through rotation. The lower end of the hook member (8) is provided with an insertion portion (11). The upper end of the crossbar pedal (4) is convexly provided with a connecting portion (12). A slot (13) is opened on the connecting portion (12). When the upper left ladder tube (2) and the right ladder tube (3) move downward and are sleeved on the lower left ladder tube (2) and the right ladder tube (3), the connecting portion (12) is provided with a slot (13). ), the hook member (8) rotates to drive the insertion portion (11) to be inserted into the slot (13), at which time the insertion rod (6) in the lower horizontal bar pedal (4) abuts against the outer wall of the upper left ladder tube (2) and the right ladder tube (3) and restricts the insertion portion (11) from being separated from the slot (13), and the lower end of the hook member (8) is also provided with an abutting portion (14), after the upper left ladder tube (2) and the right ladder tube (3) move downward, the abutting portion (14) on the hook member (8) in the upper horizontal bar pedal (4) abuts against the upper wall of the lower horizontal bar pedal (4). The connecting portion (12) of the upper crossbar pedal (4) abuts against the connecting portion (12), and the upper crossbar pedal (4) continues to move downward. At this time, the connecting portion (12) on the lower crossbar pedal (4) pushes the abutting portion (14) of the upper hook member (8) to rotate inward. At this time, the hook member (8) in the upper crossbar pedal (4) rotates around the rotating rod (10) and drives the insertion portion (11) to be inserted into the slot (13) in the connecting portion (12) of the lower crossbar pedal (4). The insertion rod (6) is rotated by the upper end of the hook member (8) and moves inward laterally to squeeze the elastic member (7); The lower ends of the left ladder tube (2) and the right ladder tube (3) are both provided with lower insertion holes (15). When the upper crossbar pedal (4) is pulled upward, the upper left ladder tube (2) and the right ladder tube (3) move upward. When the lower insertion holes (15) at the lower ends of the upper left ladder tube (2) and the right ladder tube (3) are in the same horizontal line with the insertion rod (6) in the lower crossbar pedal (4), the insertion rod (6) in the lower crossbar pedal (4) is released from the restriction and moves outward to be inserted into the lower insertion hole (15). The hook member (8) rotates around the rotating rod (10) and drives the insertion portion (11) to disengage from the slot (13). At this time, the upper crossbar pedal (4) can be pulled away from the lower crossbar pedal (4).

2. The telescopic ladder according to claim 1, characterized in that: A clamping portion (16) is provided in the middle of the insertion rod (6), and the diameter of the clamping portion (16) is smaller than the diameters of the two ends of the insertion rod (6). A clamping portion (17) is provided at the upper end of the hook member (8), and the number of the clamping portions (17) is two. The two clamping portions (17) are adjacently arranged and clamp the clamping portion (16).

3. The telescopic ladder according to claim 2, characterized in that: The hook member (8) is further provided with a pushing portion (18). When the clamping portion (17) is connected to the clamping portion (16), the pushing portion (18) abuts against the insertion rod (6). When the abutting portion (14) on the upper crossbar pedal (4) is pushed by the connecting portion (12) on the lower crossbar pedal (4), the hook member (8) rotates with the rotating rod (10), thereby pushing the insertion rod (6) inward through the pushing portion (18), and at this time, one end of the insertion rod (6) is separated from the lower insertion hole (15).

4. The telescopic ladder according to claim 3, characterized in that: The upper end of the connecting portion (12) is also provided with a sliding inclined surface (19), and a sliding surface (20) is also provided between the abutting portion (14) and the inserting portion (11). When the connecting portion (12) on the lower crossbar pedal (4) pushes the abutting portion (14) on the upper hook member (8) to rotate inward, the sliding surface (20) contacts the sliding inclined surface (19).

5. The telescopic ladder according to any one of claims 1 to 4, characterized in that: The crossbar pedal (4) is provided with a mounting groove (21), the mounting groove (21) is provided with a mounting seat (22), the mounting seat (22) is provided with a mounting hole, the elastic member (7) and one end of the insertion rod (6) are provided in the mounting hole, one end of the elastic member (7) is against the mounting hole, and the other end is in contact with the end of the insertion rod (6), when the left ladder tube (2) and the right ladder tube (3) move upwards, the lower insertion holes (15) on the left ladder tube (2) and the right ladder tube (3) are in the same horizontal line with the insertion rod (6), the elastic member (7) pushes the insertion rod (6) to move outwards and insert into the lower insertion hole (15), at which time the upper left ladder tube (2) and the right ladder tube (3) cannot move into the lower left ladder tube (2) and the right ladder tube (3), and the elastic member (7) is a spring.

6. The telescopic ladder according to claim 1, characterized in that: An upper pull rod (24) is provided above the ladder body (1), and the left ladder tube (2) and the right ladder tube (3) on both sides of the upper pull rod (24) are arranged in the left ladder tube (2) and the right ladder tube (3) on both sides of the lower crossbar pedal (4). Pulling the upper pull rod (24) upwards can drive the left ladder tube (2) and the right ladder tube (3) on both sides of the upper pull rod (24) to move upwards. When the lower insertion holes (15) at the lower ends of the left ladder tube (2) and the right ladder tube (3) on both sides of the upper pull rod (24) are in the same horizontal line with the insertion rod (6) in the lower crossbar pedal (4), the insertion rod (6) of the lower crossbar pedal (4) moves outwards and is inserted into the lower insertion hole (15).

7. The telescopic ladder according to claim 6, characterized in that: A lower bottom rod (25) is further provided below the ladder body (1), and the locking assembly (5) is also provided inside the lower bottom rod (25). The rotating member inside the lower bottom rod (25) is manually driven to rotate and drive the insertion rod (6) to move inward laterally. At this time, the insertion rod (6) is disconnected from the lower insertion holes (15) of the left ladder tube (2) and the right ladder tube (3) on the upper layer of the lower rod. At this time, the crossbar pedal (4) on the upper layer can move downward mainly along with the left ladder tube (2) and the right ladder tube (3) on both sides.

8. The telescopic ladder according to claim 1, characterized in that: An observation window (26) is also provided on one side of the crossbar pedal (4).

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