Turnover ladder beneficial to turnover operation

Abstract

The invention relates to a turnover ladder facilitating turnover operation, which comprises a front ladder assembly and a rear ladder assembly, the front ladder assembly comprises a front ladder rod, the rear ladder assembly comprises a rear ladder rod, and the rear ladder rod is hinged with the front ladder rod through a hinge structure; the folding ladder is characterized in that the hinge structure comprises a front hinge frame fixed on the front ladder rod, at least two first locking grooves are formed in the front hinge frame, and a pushing part is arranged on one side of each first locking groove; the rear hinge frame is fixed to the upper end of the rear ladder rod, the front hinge frame is rotationally connected to the upper end of the rear hinge frame, a second locking groove is further formed in the rear hinge frame, the second locking groove can be aligned with the first locking groove in the rotating process of the rear hinge frame relative to the front hinge frame, and a placement step is arranged on the side portion of the second locking groove; a driving shaft is arranged in the middle of the locking pin in a penetrating mode, and the locking pin can be inserted into the first locking groove and the second locking groove which are aligned; and the elastic piece acts on the locking pin, so that the locking pin keeps the trend of moving upwards and swinging outwards. The turnover ladder has the advantages of being reasonable in structure and convenient to change the use state.

Description

Technical Field

[0001] The invention relates to a ladder, in particular to a reversible ladder with multiple use modes and convenient for reversing operation. Background Art

[0002] Ladders are commonly used tools for climbing up or repairing things in daily life. There are two types of ladders. One is a straight ladder (also called a straight ladder). This type of ladder includes two vertical poles and a horizontal bar erected between the two vertical poles. They can only be used upright. When in use, the ladder needs to be placed on a fixed position at a high place to provide support for the ladder, and it only provides a single function of climbing. The other is a herringbone ladder. This type of ladder is mostly composed of a main ladder frame and a supporting ladder frame hinged together at the top. Compared with a straight ladder, it can perform climbing operations in a suspended position.

[0003] In order to enrich the functions of the herringbone ladder, some people have improved the structure of the traditional herringbone ladder so that the left and right ladder frames of the herringbone ladder can be relatively rotated to the same straight line and used as a straight ladder. In this way, the herringbone ladder has three states: the first state is that the left and right ladder frames are folded together, the second state is that the left and right ladder frames rotate to form a herringbone ladder, and the third state is that the left and right ladder frames rotate to form a straight ladder.

[0004] A Chinese utility model patent with patent number ZL 201921118866.7 (publication number CN 210685838 U) entitled "A Folding Ladder" discloses a multifunctional ladder, including: a front frame and a rear frame, the front frame is provided with a front foot pedal, the rear frame is provided with a rear foot pedal, one end of the front frame and the rear frame are hinged, and an unfolding fixing bracket is provided between the front frame and the rear frame. When a herringbone ladder state is required, the front frame and the rear frame are unfolded at a preset angle, and then the frame is fixed by a fixing bracket to improve the stability of the ladder; when a straight ladder state is required, the rear frame is rotated with the hinge axis as the rotating axis until the two form a straight ladder, and then fixed by locking screws; after use, the front frame and the rear frame are closed and fixed by locking screws to achieve storage. In addition, the bottom of the frame is detachably connected with a supporting foot. When the bearing surface of the supporting ladder is a step surface, the supporting foot at the bottom of the rear frame can be removed and then used. Therefore, the state of the folding ladder can be changed according to the usage scenario, thereby improving the applicability of the folding ladder.

[0005] However, the aforementioned patent has the following defects: when used as a straight ladder or a stepladder, additional and cumbersome operations are required to position it in the corresponding use position, automatic locking cannot be achieved, and the conversion operation is very inconvenient. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a reversible ladder with a reasonable structure, convenient operation for changing the use state, and more humane use, in view of the above-mentioned existing technical status.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a flip ladder that is conducive to flipping operation, comprising a front ladder frame and a rear ladder frame, the front ladder frame comprising two front ladder bars arranged at intervals on the left and right, and a plurality of front steps arranged between the two front ladder bars, the rear ladder frame comprising two rear ladder bars arranged at intervals on the left and right, and a plurality of rear steps arranged between the two rear ladder bars, the upper end of the rear ladder bar being hinged to the front ladder bar through a hinge structure; it is characterized in that: the hinge structure comprises a front hinge frame fixed to the front ladder bar, at least two first locking grooves are opened on the peripheral wall of the front hinge frame, one side of the first locking groove has a pushing part raised in the radial direction, and the pushing part smoothly transitions with the peripheral wall of the front hinge frame; the rear hinge frame fixed to the upper end of the rear ladder bar, the front hinge frame is rotatably connected to the upper end of the rear hinge frame, and the rear hinge frame is also provided with a second locking groove, so that the rear hinge frame can rotate relative to the front hinge frame during the process The second locking groove is aligned with the first locking groove, and a rest step is provided on the side of the second locking groove; a locking pin constrained in the rear hinge frame and capable of moving up and down, a driving shaft is passed through the middle of the locking pin, so that the locking pin can swing relative to the driving shaft and can move up and down with the driving shaft, and the outer end of the driving shaft exposes the rear hinge frame and is connected to the driving push-twist, and the locking pin can be inserted into the aligned first locking groove and second locking groove to lock the rear hinge frame with the front hinge frame, and lock the front ladder frame and the rear ladder frame in a herringbone ladder state or a straight ladder state; an elastic member acts on the locking pin to keep the upper end of the locking pin moving upward and swinging outward, and after the locking pin moves down and disengages from the second locking groove, the upper end of the locking pin is rested on the rest step when it swings outward, and during the rotation of the rear hinge frame relative to the front hinge frame, the pushing portion can push the upper end of the locking pin away from the rest step and align it with the second locking groove.

[0008] Preferably, the front hinge frame is in the shape of a plate, and has a connecting tail and a connecting head. The connecting tail is fixed on the front ladder rod, and the connecting head is rotatably connected to the upper end of the rear hinge frame. The second locking groove is arranged on the peripheral wall of the connecting head. The plate-shaped front hinge frame is convenient for stamping by plate parts, and the manufacturing is simple, convenient and low-cost. The front hinge frame is composed of a plate-shaped connecting tail and a plate-shaped connecting head. The plate-shaped connecting tail is convenient for fixing on the side of the front ladder rod, and has a large contact area with the front ladder rod, so the fixation is more secure. The plate-shaped connecting head is also convenient for rotatably connecting with the upper end of the rear hinge frame, and has a large contact area with each other. The relative rotation of the two is not easy to shake and is more stable.

[0009] As an improvement, the rear hinge frame has a hollow insertion part for being inserted and fixed in the rear ladder rod, the top of the insertion part has two sandwiching walls spaced apart in front and back, the center of the connecting head is inserted between the two sandwiching walls and rotated on the sandwiching walls through a pivot; the rear hinge frame passes through the rear ladder rod of the insertion part, and the rear ladder rod forms a circumferential constraint on the rear hinge frame, which is conducive to firmly fixing the rear hinge frame and the rear ladder rod, and the connecting head is inserted and constrained between the two sandwiching walls, so that the front hinge frame and the rear hinge frame are more smoothly connected in rotation. The locking pin has a rod part and a locking head, the driving shaft is passed through the middle part of the rod part, the locking head is fixed to the head end of the rod part, and the front and rear end surfaces of the insertion part are provided with a clearance groove for the locking head to be exposed, the second locking groove is connected to the clearance groove, and the inner top edge of the clearance groove constitutes the resting step. The locking pin is divided into two parts, a rod and a lock head, and the two parts can be manufactured independently. The rod can be hollow or U-shaped. Since the lock head has to play a locking role, it is suitable to make the lock head solid, and the size of the lock head can be enlarged so that its size can be inserted into the first locking groove and the second locking groove at the same time as much as possible. The setting of the give way groove provides space for the lock head that reveals the clamping wall to move and swing, and the inner top edge of the give way groove naturally forms a shelf step, and the structural layout is reasonable.

[0010] For easy assembly, the rear hinge frame is formed by the front half shell and the rear half shell being fixed together. This makes it convenient to arrange the locking pin and the elastic member inside the rear hinge frame. When assembling, the locking pin and the elastic member are first installed on one of the half shells, and then the other half shell is closed.

[0011] Preferably, the elastic member is a tension spring, the upper end of which is fixed to the rear hinge frame, and the lower end of which is connected to the lower end of the locking pin and applies an oblique upward pulling force to the lower end of the locking pin. The tension spring has the advantage of being easy to assemble, and the inclined tension spring exerts an oblique upward pulling force on the lower end of the locking pin, which forms a horizontal component and an upward component on the locking pin. The horizontal component causes the upper end of the locking pin to swing outward, and the upward component causes the locking pin to move upward, thereby meeting the design requirements. Of course, the elastic member can also be composed of two independent components, such as a torsion spring and a compression spring.

[0012] Further improvement, when it is used as a herringbone ladder, the rear ladder frame mainly plays a supporting role, so the rear pedal is not used for stepping, therefore, the rear pedal and the front pedal can be installed in reverse, ensuring that when it is used as a straight ladder after rotation, the rear pedal and the front pedal are parallel. When used as a herringbone ladder, the tread of the front pedal faces upwards, and the tread of the rear pedal faces downwards.

[0013] As a further improvement, the front hinge frame is fixed to the front ladder rod under the uppermost front step, so that when it is rotated to the use state of the straight ladder, the front ladder rod and the rear ladder rod are partially misaligned and directly or indirectly abut against each other. When the straight ladder is in use, the front ladder rod and the rear ladder rod are partially misaligned and directly or indirectly abut against each other to support each other, so that the force between the locking pin and the locking groove will be very small, and no compression will be caused between the locking pin and the locking groove, effectively protecting the hinge structure.

[0014] As a further improvement, a tool box with a accommodating cavity is fixed between the top ends of the two front ladder rods, and a box cover is hinged on the tool box. After the box cover is closed, when the straight ladder is in use, the tool box is used as a pedal, and the rear ladder rod abuts against the rear of the tool box and indirectly abuts against the front ladder rod. The tool box provides a suitable placement space for various tools. When used as a stepladder, people can use the tool box while standing on the front ladder frame, without having to go up and down to take tools, which is more user-friendly. When used as a straight ladder, the tool box can also be used as a pedal, achieving a dual-purpose effect.

[0015] As an improvement, the end surface of the tool box has a limit portion protruding backwards. When the straight ladder is in use, the limit portion is embedded between the two rear ladder rods, and the side of the limit portion contacts the inner side of the rear ladder rod. The limit portion constrains the rear ladder rod. When used as a straight ladder, the rear ladder frame will not shake relative to the front ladder frame, and the overall structure is stable.

[0016] As a further improvement, the front ladder rod has a vertical section, an inclined section and a connecting section, the inclined section is inclined outward from top to bottom, the lower end of the vertical section is connected to the upper end of the inclined section through the connecting section, and the front hinge frame is fixed to the vertical section. This structure makes the lower end of the front ladder rod tend to open, so that it can be placed on the ground more stably whether used as a herringbone ladder or a straight ladder.

[0017] Compared with the prior art, the present invention has the advantages that the present invention is very convenient to operate when switching functions. When switching, it is only necessary to move the driving push knob, and the locking pin moves downward to disengage from the first locking groove and the second locking groove. After disengagement, the locking pin swings outward under the action of the elastic member, and its upper end rests on the resting step. The locking pin is in the unlocked position, so that the rear ladder frame and the hinge frame can rotate relative to the front hinge frame together. Before the block rotates to the herringbone ladder state or the straight ladder state (the first locking groove and the second locking groove are about to be aligned), the push portion can push the upper end of the locking pin away from the resting step and align it with the second locking groove (the first locking groove and the second locking groove are aligned). The locking pin moves upward under the action of the elastic member, and is inserted into the aligned first locking groove and the second locking groove to lock the rear hinge frame with the front hinge frame, and the front ladder frame and the rear ladder frame are locked in the herringbone ladder state or the straight ladder state. The entire operation process only requires the initial movement of the driving push knob, and in the subsequent rotation process, there is no need to use the hand to drive the push knob, and the switching operation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the three-dimensional structure of an embodiment of the present invention Figure 1 (Usage status of herringbone ladder);

[0019] Figure 2 Schematic diagram of the three-dimensional structure of an embodiment of the present invention Figure 2 (Usage status of herringbone ladder);

[0020] Figure 3 for Figure 2 A magnified image of point A;

[0021] Figure 4 It is an exploded schematic diagram of the hinge structure of the stepladder in the embodiment of the present invention when it is in use;

[0022] Figure 5 Schematic diagram of the three-dimensional structure of an embodiment of the present invention Figure 1 (Elevator usage status);

[0023] Figure 6 Schematic diagram of the three-dimensional structure of an embodiment of the present invention Figure 2 (Elevator usage status);

[0024] Figure 7 It is an exploded schematic diagram of the hinge structure of the vertical ladder in the embodiment of the present invention when in use;

[0025] Figure 8 A three-dimensional schematic diagram of the hinge structure of the embodiment of the present invention when preparing to switch to a use state;

[0026] Fig. 9 A three-dimensional exploded view of the hinge structure of the embodiment of the present invention when preparing to switch the use state;

[0027] Fig.10 A three-dimensional exploded view of the hinge structure when the embodiment of the present invention is about to be switched to a stepladder use state is prepared. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings.

[0029] like Figures 1 to 10 Shown is a preferred embodiment of the present invention.

[0030] A reversible ladder that facilitates reversing operation includes a front ladder frame 1 and a rear ladder frame 2. The front ladder frame 1 includes two front ladder rods 11 spaced apart from each other, and a plurality of front pedals 12 disposed between the two front ladder rods 11. The rear ladder frame 2 includes two rear ladder rods 21 spaced apart from each other, and a plurality of rear pedals 22 disposed between the two rear ladder rods 21. The upper end of the rear ladder rod 21 is hinged to the front ladder rod 11 through a hinge structure. The front ladder rod 11 has a vertical section 11a, an inclined section 11b, and a connecting section 11c. The inclined section 11b is inclined outward from top to bottom. The lower end of the vertical section 11a is connected to the upper end of the inclined section 11b through the connecting section 11c. The rear pedal 22 is installed in reverse to the front pedal 12, so that when the rear pedal 22 is in parallel with the front pedal 12 after rotation in the straight ladder use state.

[0031] The main improvement of the present invention lies in the hinge structure. Specifically, the hinge structure includes

[0032] The front hinge frame 3 is fixed to the side wall of the vertical section 11a of the front ladder rod 11, and at least two first locking grooves 31 are opened on the peripheral wall of the front hinge frame 3. One side of the first locking groove 31 has a radially raised pushing portion 311, and the pushing portion 311 smoothly transitions with the peripheral wall of the front hinge frame 3.

[0033] The rear hinge frame 5 is fixed to the upper end of the rear ladder rod 21, and the front hinge frame 3 is rotatably connected to the upper end of the rear hinge frame 5. The rear hinge frame 5 is also provided with a second locking groove 51. When the rear hinge frame 5 rotates relative to the front hinge frame 3, the second locking groove 51 can be aligned with the first locking groove 31, and a side of the second locking groove 51 is provided with a resting step 521.

[0034] A locking pin 6 is constrained in the rear hinge frame 5 and can move up and down. A driving shaft 7 is passed through the middle of the locking pin 6, so that the locking pin 6 can swing relative to the driving shaft 7 and move up and down with the driving shaft 7. The outer end of the driving shaft 7 is exposed from the rear hinge frame 5 and is connected to the driving push-twist 71. The locking pin 6 can be inserted into the aligned first locking groove 31 and the second locking groove 51 to lock the rear hinge frame 5 with the front hinge frame 3, and the front ladder frame 1 and the rear ladder frame 2 are locked in a herringbone ladder state or a straight ladder state.

[0035] The elastic member 4 acts on the locking pin 6 to keep the upper end of the locking pin 6 moving upward and swinging outward. After the locking pin 6 moves downward and disengages from the second locking groove 51, the upper end of the locking pin 6 rests on the resting step 521 when it swings outward. During the rotation of the rear hinge frame 5 relative to the front hinge frame 3, the pushing portion 311 can push the upper end of the locking pin 6 away from the resting step 521 and align it with the second locking groove 51. The elastic member 4 is preferably a tension spring, the upper end of which is fixed to the rear hinge frame 5, and the lower end of which is connected to the lower end of the locking pin 6 and applies an oblique upward pulling force to the lower end of the locking pin 6.

[0036] The front hinge frame 3 is plate-shaped and has a connecting tail portion 3a and a connecting head portion 3b. The connecting tail portion 3a and the connecting head portion 3b are connected by a vertical wall to form a Z shape as a whole. The connecting tail portion 3a is fixed on the front ladder rod 11, and the connecting head portion 3b is rotatably connected to the upper end of the rear hinge frame 5. The second locking groove 51 is provided on the peripheral wall of the connecting head portion 3b.

[0037] The rear hinge frame 5 is formed by the front half shell and the rear half shell being fixed together. The rear hinge frame 5 has a hollow insertion portion 5a for being inserted and fixed in the rear ladder rod 21. The top of the insertion portion 5a has two sandwiching walls 5b spaced apart from each other. The center of the connecting head 3b is inserted between the two sandwiching walls 5b and rotated on the sandwiching walls 5b through the pivot 3c. The locking pin 6 has a rod 61 and a lock head 62. The driving shaft 7 is passed through the middle of the rod 61. The lock head 62 is fixed to the head end of the rod 61. The front and rear end surfaces of the insertion portion 5a are provided with a clearance groove 52 for the lock head 62 to be exposed. The second locking groove 51 is connected to the clearance groove 52. The inner top edge of the clearance groove 52 constitutes the resting step 521.

[0038] The front hinge frame 3 is fixed on the front ladder rod 11 below the uppermost front pedal 12, so that after rotation, when the vertical ladder is in use, the front ladder rod 11 and the rear ladder rod 21 are partially misaligned and directly or indirectly abut against each other.

[0039] A tool box 8 having a receiving cavity is fixed between the top ends of the two front ladder bars 11, and a box cover 81 is hinged on the tool box 8. When the box cover 81 is closed, the tool box 8 is used as a step when the ladder is in use, and the rear ladder bar 21 abuts against the rear of the tool box 8 and indirectly abuts against the front ladder bar 11. The end surface of the tool box 8 has a limit portion 82 protruding backwards. When the ladder is in use, the limit portion 82 is embedded between the two rear ladder bars 21, and the side of the limit portion 82 contacts the inner side surface of the rear ladder bar 21.

[0040] The working principle and process of this tilting ladder are as follows:

[0041] In the initial folded state, the upper end of the locking pin 6 is placed on the placing step 521, and the front ladder frame 1 and the rear ladder frame 2 are in a closing trend.

[0042] like Figures 1 to 4 8 to 10, the process of adjusting the ladder to a herringbone ladder and using the straight ladder is as follows: the rear ladder frame 2 is opened outward relative to the front ladder frame 1, and the rear hinge frame 5 is swung backward until the push portion 311 on one side of the first locking groove 31 just passes over the lock head 62 of the locking pin 6 resting on the resting step 521 (as shown in FIG. Figures 8 to 10As shown in the figure, the second locking groove 51 and the first locking groove 31 are just misaligned, disengaged and then the rear ladder frame 2 is slightly rotated in the opposite direction, the pushing portion 311 pushes the locking head 62 of the locking pin 6 away from the resting step 521, at this time, one of the second locking grooves 51 is aligned with the first locking groove 31, and the locking pin 6, under the action of the elastic member 4, makes the locking head 62 thereon insert into the aligned first locking groove 31 and the second locking groove 51 to lock the rear hinge frame 5 and the front hinge frame 3 in the herringbone ladder position.

[0043] like Figures 5 to 7 As shown, the step ladder is adjusted to a straight ladder. The process of using the straight ladder is as follows: the locking head 62 is moved downward along with the locking pin 6 to disengage from the first locking groove 31 and the second locking groove 51. After disengagement, the locking pin 6 swings outward under the action of the elastic member 4, and its upper end rests on the resting step 521. The locking pin 6 is in the unlocked position, so that the rear ladder frame 2 and the hinge frame 5 can rotate relative to the front hinge frame 3. Before the block rotates to the straight ladder state (the first locking groove 31 and the other second locking groove 51 are about to be aligned), the pushing portion 521 can push the locking head 62 of the locking pin 6 away from the resting step 521 and align it with the aligned first locking groove 31 and the second locking groove 51. The locking pin 6 moves upward under the action of the elastic member 4, and the locking head 62 thereon is inserted into the aligned first locking groove 31 and the second locking groove 52 to lock the rear hinge frame 5 and the front hinge frame 3 in the straight ladder state.

[0044] The entire adjustment operation process only requires the initial movement of the driving push knob 71. During the subsequent rotation process, there is no need to manually drive the pushing knob 71, and the switching operation is convenient.

[0045] It should be noted that in the description of this embodiment, the terms "front, back", "left, right", "inside, outside", "upper, lower" and the like indicating directions or positional relationships are all based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. The terms "install", "connect", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A flip ladder that facilitates flipping operation, comprising a front ladder frame (1) and a rear ladder frame (2), wherein the front ladder frame (1) comprises two front ladder rods (11) spaced apart from each other on the left and right sides, and a plurality of front pedals (12) disposed between the two front ladder rods (11), and the rear ladder frame (2) comprises two rear ladder rods (21) spaced apart from each other on the left and right sides, and a plurality of rear pedals (22) disposed between the two rear ladder rods (21), and the upper ends of the rear ladder rods (21) are hingedly connected to the front ladder rods (11) through a hinge structure; characterized in that: The hinge structure includes A front hinge frame (3) fixed on the front ladder rod (11), wherein at least two first locking grooves (31) are formed on the peripheral wall of the front hinge frame (3), and one side of the first locking groove (31) has a radially raised pushing portion (311), and the pushing portion (311) smoothly transitions to the peripheral wall of the front hinge frame (3); A rear hinge frame (5) is fixed to the upper end of the rear ladder rod (21), the front hinge frame (3) is rotatably connected to the upper end of the rear hinge frame (5), and a second locking groove (51) is also provided on the rear hinge frame (5). When the rear hinge frame (5) rotates relative to the front hinge frame (3), the second locking groove (51) can be aligned with the first locking groove (31), and a side portion of the second locking groove (51) is provided with a resting step (521); A locking pin (6) is constrained in the rear hinge frame (5) and can move up and down. A driving shaft (7) is passed through the middle of the locking pin (6) so that the locking pin (6) can swing relative to the driving shaft (7) and can move up and down with the driving shaft (7). The outer end of the driving shaft (7) is exposed from the rear hinge frame (5) and is connected to the driving push-twist (71). The locking pin (6) can be inserted into the aligned first locking groove (31) and the second locking groove (51) to lock the rear hinge frame (5) and the front hinge frame (3), and the front ladder frame (1) and the rear ladder frame (2) are locked in a herringbone ladder state or a straight ladder state. The elastic member (4) acts on the locking pin (6) to keep the upper end of the locking pin (6) moving upward and swinging outward. After the locking pin (6) moves downward and disengages from the second locking groove (51), the upper end of the locking pin (6) rests on the resting step (521) when swinging outward. During the rotation of the rear hinge frame (5) relative to the front hinge frame (3), the pushing portion (311) can push the upper end of the locking pin (6) away from the resting step (521) and align it with the second locking groove (51).

2. The reversible ladder that facilitates reversal operation according to claim 1, characterized in that: The front hinge frame (3) comprises a connecting tail portion (3a) and a connecting head portion (3b), wherein the connecting tail portion (3a) is fixed on the front ladder rod (11), and the connecting head portion (3b) is rotatably connected to the upper end of the rear hinge frame (5), and the second locking groove (51) is arranged on the peripheral wall of the connecting head portion (3b).

3. The reversible ladder that facilitates reversal operation according to claim 2, characterized in that: The rear hinge frame (5) has a hollow insertion portion (5a) for being inserted and fixed in the rear ladder rod (21), the top of the insertion portion (5a) has two sandwiching walls (5b) arranged at intervals in front and back, the center of the connecting head (3b) is inserted between the two sandwiching walls (5b) and rotated on the sandwiching walls (5b) through a pivot (3c); the locking pin (6) has a rod portion (61) and a locking head (62), the driving shaft (7) is passed through the middle of the rod portion (61), the locking head (62) is fixed to the head end of the rod portion (61), and the front and rear end surfaces of the insertion portion (5a) are provided with a clearance groove (52) for the locking head (62) to be exposed, the second locking groove (51) is connected to the clearance groove (52), and the inner top edge of the clearance groove (52) constitutes the resting step (521).

4. The reversible ladder that facilitates reversal operation according to claim 3 is characterized in that: The rear hinge frame (5) is formed by a front half shell and a rear half shell being joined and fixed together.

5. The reversible ladder that facilitates reversal operation according to claim 1, characterized in that: The elastic member (4) is a tension spring, the upper end of which is fixed to the rear hinge frame (5), and the lower end of which is connected to the lower end of the locking pin (6) and applies an oblique upward pulling force to the lower end of the locking pin (6).

6. The reversible ladder that facilitates reversal operation according to claim 1, characterized in that: The rear pedal (22) and the front pedal (12) are installed in opposite directions, so that after being rotated, when the vertical ladder is in use, the rear pedal (22) and the front pedal (12) are parallel.

7. The reversible ladder that facilitates reversal operation according to claim 1, characterized in that: The front hinge frame (3) is fixed to the front ladder rod (11) below the uppermost front pedal (12), so that after rotation, when the straight ladder is in use, the front ladder rod (11) and the rear ladder rod (21) are partially misaligned and directly or indirectly abut against each other.

8. The reversible ladder that facilitates reversal operation according to claim 7, characterized in that: A tool box (8) having a receiving cavity is fixed between the top ends of the two front ladder rods (11), and a box cover (81) is hingedly connected to the tool box (8). When the box cover (81) is closed, when the ladder is in use, the tool box (8) is used as a step, and the rear ladder rod (21) abuts against the rear of the tool box (8) and indirectly abuts against the front ladder rod (11).

9. The overturnable ladder that facilitates overturning operation according to claim 8, characterized in that: The end surface of the tool box (8) has a limiting portion (82) protruding backwards. When the ladder is in use, the limiting portion (82) is embedded between the two rear ladder bars (21), and the side of the limiting portion (82) contacts the inner side surface of the rear ladder bar (21).

10. The reversible ladder that facilitates reversal operation according to claim 1, characterized in that: The front ladder bar (11) comprises a vertical section (11a), an inclined section (11b) and a connecting section (11c); the inclined section (11b) is inclined outward from top to bottom; the lower end of the vertical section (11a) is connected to the upper end of the inclined section (11b) via the connecting section (11c); and the front hinge frame (3) is fixed on the vertical section (11a).

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