CN115405219A

CN115405219A - Combined ladder

Info

Publication number: CN115405219A
Application number: CN202211017944.0A
Authority: CN
Inventors: 谢小燕; 杨贵军
Original assignee: Suzhou Laien Precision Alloy Co ltd; Suzhou Pica Aluminum Industry Co Ltd
Current assignee: Suzhou Laien Precision Alloy Co ltd; Suzhou Pica Aluminum Industry Co Ltd
Priority date: 2022-08-24
Filing date: 2022-08-24
Publication date: 2022-11-29

Abstract

A combined ladder, which adjusts and locks the opening state of a ladder through an adjusting piece, comprises a front ladder frame and a rear ladder frame, wherein the upper ends of the two ladder frames are hinged through a hinge joint, and the two ladder frames comprise an inner ladder, an outer ladder and a locking device for locking the inner ladder and the outer ladder; the hinge joint comprises an inner hinge piece, an outer hinge piece and two pairs of limiting structures which are rotatably assembled; the two pairs of limiting structures comprise a first limiting part and a second limiting part; at least one pair of limiting structures in the two pairs of limiting structures are supplementary limiting structures; when the ladder is opened and is not overloaded, a gap exists between the first limiting part and the second limiting part of the supplementary limiting structure; when the ladder is opened and overloaded, the first limiting part and the second limiting part of the supplementary limiting structure are mutually abutted and matched; the limiting structure in the scheme is simple and easy to operate, and the safety of the ladder is improved.

Description

Combined ladder

Technical Field

The invention relates to a climbing appliance, in particular to a combined ladder.

Background

The ladder is a common climbing tool in daily work and life, and is commonly provided with a ladder with non-adjustable height and a ladder with adjustable height. Wherein the ladder with adjustable height comprises a telescopic ladder and a combined ladder; the combined ladder comprises a front ladder frame, a rear ladder frame and a hinge joint which is hinged to the upper end of the front ladder frame and the lower end of the rear ladder frame, wherein the front ladder frame and the rear ladder frame respectively comprise an inner ladder, an outer ladder sleeved on the inner ladder and a locking device for fixing the outer ladder on the inner ladder.

The combined ladder has two states of opening and folding, wherein when the combined ladder is opened, the combined ladder can be made to be in the opening state and kept in the opening state through the adjusting piece; the open state generally includes a herringbone-like "herringbone ladder" and a nearly straight "straight ladder state". The climbing operation is a high-risk operation, and the ladder is required to ensure enough safety when in use, particularly in a straight ladder state and under an overload condition, the inner hinge piece and the outer hinge piece of the hinge joint are in a straight shape and are more sensitive to external force, in the prior art, the adjusting piece of the ladder is only used for resisting the external force and keeping the straight shape of the inner hinge and the outer hinge, the long-term use can cause abrasion, the strength is reduced, namely the weight born by the adjusting piece is gradually reduced, but an abrasion user is not easy to find, when the load of a certain time is in an originally specified range but exceeds the bearing capacity of the adjusting piece after the abrasion, the adjusting piece can be broken and lose the locking function of the ladder, and the accident of the user is caused.

Therefore, how to solve the above-mentioned deficiencies of the prior art is a problem to be solved by the present invention.

Disclosure of Invention

The invention aims to provide a combined ladder.

In order to achieve the purpose, the invention adopts the technical scheme that: the combined ladder is adjusted and locked in the opening state of the ladder through an adjusting piece, and is characterized in that: the ladder comprises a front ladder frame and a rear ladder frame, wherein the upper ends of the two ladder frames are hinged through a hinge joint, and the two ladder frames respectively comprise an inner ladder, an outer ladder and a locking device for locking the inner ladder and the outer ladder;

the hinge joint comprises an inner hinge piece, an outer hinge piece and two pairs of limiting structures, wherein the inner hinge piece and the outer hinge piece are assembled in a rotating mode;

the two pairs of limiting structures comprise a first limiting part and a second limiting part; at least one pair of limiting structures in the two pairs of limiting structures are supplementary limiting structures; when the ladder is opened and is not overloaded, a gap exists between the first limiting part and the second limiting part of the supplementary limiting structure; when the ladder is opened and overloaded, the first limiting part and the second limiting part of the supplementary limiting structure are mutually abutted and matched; the first limiting part and the second limiting part are respectively positioned on the inner hinge piece and the outer hinge piece which are hinged with each other in the hinge joint.

In the scheme, the overload means that the quality of ascending personnel or other loaded on the ascending ladder exceeds the locking capacity of the regulating part on the ladder, when the locking capacity of the regulating part is exceeded, the regulating part can break and lose the locking function on the ladder, at the moment, the two pairs of limiting structures abut against each other through the first limiting part and the second limiting part of the limiting structures, the opening state of the ladder is continuously kept, the ladder is kept in the opening state and is not influenced by the breakage of the regulating part, accidents of users are prevented, the safety factor of the ladder is improved, and when the two pairs of limiting structures abut against each other, gaps between the limiting parts are eliminated instantly to generate jitter and sound, the users are reminded that the locking structures are damaged, and the damaged locking structures can be replaced in time.

In the above scheme, at least one pair of limiting structures in the two pairs of limiting structures is a supplementary limiting structure, because the first limiting part in the other limiting structure is a limiting block arranged on the outer side of the inner hinge piece, the second limiting part is a limiting groove, the limiting block is of an externally attached structure, the strength is low, the impact force at a moment is difficult to resist, and the long-time independent use is not suitable.

According to the further technical scheme, a first limiting part in a supplementary limiting structure in the limiting structure is a limiting lug, and a second limiting part is a lug boss; the head part of the outer hinge plate is a rotating disc, and a gap is formed in the thickness direction of the rotating disc; the head part of the inner hinge sheet is a positioning disc which is rotatably arranged in a gap of the rotating disc and is hinged with the rotating disc; the boss is arranged on the outer edge of the positioning disc and extends along the radial direction of the positioning disc; the limiting lug is a thick plate block fixedly arranged in the gap of the rotating disc, and the end face of the limiting lug is arranged corresponding to the boss.

According to the further technical scheme, a first limiting part in the other limiting structure in the limiting structures is a limiting block, and a second limiting part is a limiting groove; the outer side of the inner hinge piece is provided with a limiting block, and the outer hinge piece is provided with a limiting groove corresponding to the limiting block. According to the further technical scheme, the adjusting piece is arranged corresponding to the central shafts of the rotating disc and the positioning disc and used for at least locking the opening states of the rotating disc and the positioning disc; the adjusting piece comprises a handle, a hinge shaft arranged on the handle and a pair of second limiting columns; the hinge shaft is arranged along the central axis direction of the rotating disc and the positioning disc; the second limiting columns are respectively arranged on two sides of the hinged shaft; a pair of first through holes are formed in the positioning disc, and the first through holes are symmetrically arranged on two sides of a central shaft of the positioning disc; a pair of second through holes and a pair of third through holes are formed in the rotating disc; the second through holes and the third through holes are symmetrically arranged on two sides of a central shaft of the rotating disc, and the second through holes and the third through holes are alternately arranged around the central shaft; when the ladder is opened, the second limiting column is in aligned splicing with the first through hole and the second through hole simultaneously or in aligned splicing with the first through hole and the third through hole simultaneously; the second limiting column is in aligned insertion with the first through hole and the second through hole or the first through hole and the third through hole at the same time to correspondingly lock different opening states of the ladder; the through holes are not limited to the second through hole and the third through hole, and a plurality of through holes (not shown in the figure) can be arranged to lock the ladder at different angles; when the ladder state needs to be adjusted, the adjusting piece is pulled out outwards, and then the handle is rotated, so that the second limiting columns correspond to and are inserted into the corresponding through holes.

The four locking devices are respectively arranged corresponding to the inner ladder post and the outer ladder post on the left side of the front ladder frame, the inner ladder post and the outer ladder post on the right side of the front ladder frame, the inner ladder post and the outer ladder post on the left side of the rear ladder frame and the inner ladder post and the outer ladder post on the right side of the rear ladder frame; the locking device comprises a locking handle, two ends of the locking handle are respectively connected with a locking column and a first limiting column, and the locking column and the first limiting column are arranged in the same direction; in a locked state, the locking column extends into any one of the inner locking holes on the inner ladder columns through the outer locking hole on the outer ladder column; an end cover which can be fastened in a self-adaptive manner and can be expanded through self deformation is fixedly arranged at the end part of a pedal on the outer ladder, and a fourth through hole through which the first limiting column penetrates is formed in the end cover; the first spring acts between the first limiting column and the pedal, so that the first limiting column keeps a trend of moving towards the inside of the fourth through hole.

In the scheme, the ladder post of the outer ladder is slidably sleeved on the ladder post of the inner ladder, and the ladder post of the outer ladder is provided with an outer locking hole; a plurality of inner locking holes are formed in the ladder post of the inner ladder corresponding to the outer locking holes, and the inner locking holes are arranged at intervals along the length direction of the ladder post of the inner ladder; the locking device is fixedly arranged on the ladder post of the outer ladder, and the outer locking hole and the inner locking hole at any height position are locked at the same time, so that the position relation of the inner ladder and the outer ladder is positioned.

In the above-mentioned scheme, the end cover can expand tightly through self deformation production, like first spring inflation piece, bars piece etc. place the footboard in this end cover in, through the inner wall extrusion fit of its self deformation production expand tightly realize with the footboard, increased frictional resistance on the one hand, prevent that the end cover from following the inside and outside removal of first spacing post, on the other hand can omit the mounting fixed, makes the installation simpler.

According to the further technical scheme, the periphery of the end cover comprises a plurality of grid pieces extending along the direction that the end cover is inserted into the pedal, so that the assembly is more convenient; in addition, the grid pieces on the periphery of the end cover can be arranged along the direction perpendicular to the direction in which the end cover is inserted into the pedal, so that the fastening effect is better, and the grid pieces are not easy to pull out; the design of the plurality of grids not only meets the self-adaptive fastening requirement of the end cover, but also meets the integral strength requirement of the end cover, and the integral fixation of the end cover cannot be influenced even if individual grids are damaged due to the extrusion of the pedal.

According to a further technical scheme, the diameter of the first limiting column is smaller than that of the locking handle; the end cover comprises an inner layer and an outer layer, wherein the inner layer is of a solid structure, and the outer layer is of a grid structure.

According to the further technical scheme, a cavity is formed in the pedal and is arranged along the length direction of the pedal; wherein the chamber is in communication with the fourth through-hole; a limiting rod with the diameter not larger than that of the first limiting column extends from the first limiting column, the limiting rod is arranged corresponding to the cavity, and the free end of the limiting rod is limited in the cavity; the first spring is sleeved on the limiting rod and acts between the limiting rod and the pedal, so that the limiting rod keeps a trend of moving towards the inside of the cavity; the limiting rod can be formed by directly extending the first limiting column, or the limiting rod and the first limiting column can be two parts respectively, but the two parts are in rigid connection.

According to the further technical scheme, a check ring is sleeved on the limiting rod, and the first spring acts between the end cover and the check ring to enable the limiting rod to keep a trend of moving towards the interior of the cavity; by means of the design, when the locking handle is pulled out outwards and the locking column is aligned to the inner locking hole and the outer locking hole at the same time, the locking handle is loosened, the locking column is automatically clamped into the inner locking hole and the outer locking hole, and the ladder is in a locking state.

According to the further technical scheme, a first limiting step is arranged in the middle of the locking column to limit the depth of the locking column extending into the inner locking hole; meanwhile, the abutting limiting surfaces of the locking column and the outer ladder column are increased, so that the locking effect of the locking device is greatly improved when the ladder is used, and the stability of the locking device is improved. The middle part of the first limiting column is provided with a second limiting step to limit the depth of the fourth through hole of the end cover into which the first limiting column extends; meanwhile, the first limiting column and the end cover are additionally arranged to abut against the limiting surface, so that the locking effect of the locking device is greatly improved when the ladder is used, and the stability of the locking device is also improved.

Compared with the prior art, the combined ladder in the scheme has the following advantages:

1. when the combined ladder is opened to be in a straight-line state and is not overloaded, the straight-line state of the combined ladder is locked only by the adjusting piece, a gap is reserved between the first limiting part and the second limiting part of at least one pair of limiting structures in the two pairs of limiting structures on the hinge piece, when the straight-line state of the combined ladder is overloaded and exceeds the locking capacity of the adjusting piece or the adjusting piece is broken, the two pairs of first limiting parts and the second limiting parts on the hinge piece are abutted against each other, the straight-line locking state of the ladder is continuously kept, and accidents of a user are prevented; meanwhile, the ladder tool can shake and make a sound in the process that the first limiting part and the second limiting part abut against each other from a gap, so that a user can be reminded that the combined ladder is overloaded or an adjusting part of the combined ladder is damaged, and the safety factor of the combined ladder is greatly improved.

2. At least one pair of limiting structures in the two pairs of limiting structures is a supplementary limiting structure, so that a limiting block and a limiting groove in the other limiting structure are prevented from being instantly abutted against each other due to strong impact force, the service life of the combined ladder is prolonged, and the safety factor of the ladder is improved.

3. The locking device replaces a shell-shaped and easily damaged end cover in the prior art by fully utilizing the end cover fastened by the end part of the pedal in a self-adaptive manner, and solves the problems that the end cover and the plug fixed by the rivet are easily loosened and the complex process of fixing by the rivet is caused by frequent pulling and inserting of the locking structure when in use.

4. The self-adaptive fastening end cover is provided with a thick solid inner layer and an expansion fastening layer, and is not easy to damage while being firmly combined with the pedal.

Drawings

Fig. 1 is a perspective view of a combination ladder according to an embodiment of the present invention;

fig. 2 is a right side view of a combination ladder according to an embodiment of the present invention;

FIG. 3 is an exploded view of a front ladder rack in accordance with an embodiment of the present invention;

FIG. 4 is an enlarged view of the locking device at A of FIG. 3;

FIG. 5 is a perspective view of a locking device according to an embodiment of the present invention;

FIG. 6 is a schematic view of the partial cross-sectional structure of FIG. 5 (with the locking device in a locked condition);

FIG. 6a is a schematic view of a partial cross-sectional structure of a locking device in an unlocked state in accordance with an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a hinge joint according to an embodiment of the present invention;

FIG. 8 is a schematic structural view of an inner hinge plate according to an embodiment of the present invention;

FIG. 9 is a schematic view of the assembly of the hinge plate and the adjusting member according to the embodiment of the present invention;

FIG. 10 is a partial exploded view of FIG. 9;

FIG. 11 is a schematic structural view of a hinge joint of an embodiment of the present invention in a herringbone ladder state;

fig. 12 is a schematic structural view of a hinge joint in a linear ladder state according to an embodiment of the present invention.

In the above drawings: 1. an inner ladder; 2. an outer ladder; 3. a front ladder frame; 4. a pedal; 5. an inner locking hole; 6. an outer locking hole; 7. a locking device; 8. a locking handle; 9. a locking post; 10. a first limit post; 11. a rear ladder frame; 12. a chamber; 13. an end cap; 14. a fourth via hole; 15. a limiting rod; 16. a retainer ring; 17. a first spring; 18. a first limit step; 19. a second limit step; 20. an oblique support member; 21. an inner hinge piece; 22. an outer hinge plate; 23. a limiting block; 24. a limiting groove; 25. positioning a plate; 26. rotating the disc; 27. a limiting bump; 27a, limiting the end surface of the bump; 29. a boss; 31. an adjustment member; 32. an adjusting handle; 33. a hinge axis; 34. a second limit post; 35. a first through hole; 36. a second through hole; 37. a third through hole; 39. an operation section; 40. a second spring; 41. and (5) connecting the surface.

Detailed Description

The invention is further described with reference to the following figures and examples:

example (b): the present disclosure will be described in detail and with reference to the drawings, and it is to be understood that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms "a", "an", "the" and "the", as used herein, also include the plural forms.

The terms "first," "second," and the like, as used herein, are not intended to be limited to a particular order or sequence, nor are they intended to be used to limit the scope of the present disclosure, but only to distinguish components or operations described by the same terms.

As used herein, "connected" or "positioned" refers to two or more elements or devices being in direct or indirect physical contact with each other, and may also refer to two or more elements or devices being in operation or action with each other.

As used herein, the terms "comprising," "having," and the like, are open-ended terms that mean including, but not limited to.

As used herein, the term (terms), unless otherwise indicated, shall generally have the ordinary meaning as commonly understood by one of ordinary skill in the art, in this written description and in the claims. Certain terms used to describe the disclosure are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the disclosure.

The terms "front", "rear", "left", "right", and the like used herein are directional terms, and are used herein only to describe the positional relationship between the structures, and are not intended to limit the protection schemes and the specific directions in practical implementation.

Referring to fig. 1 to 12, a combination ladder, which adjusts and locks an open state of ladder sets by an adjusting member 31, includes a front ladder frame 3 and a rear ladder frame 11, wherein upper ends of the front ladder frame 3 and the rear ladder frame 11 are hinged by a hinge joint; the front ladder frame 3 and the rear ladder frame 11 comprise an inner ladder 1, an outer ladder 2 sleeved on the inner ladder 1 and a locking device 7 used for locking the inner ladder and the outer ladder.

See figures 7-12 for an illustration: the hinge joint comprises an inner hinge plate 21 and an outer hinge plate 22 which are rotatably assembled and two pairs of limiting structures; the two pairs of limiting structures comprise a first limiting part and a second limiting part; at least one pair of limiting structures in the two pairs of limiting structures are supplementary limiting structures; when the ladder is opened without overload, a gap exists between the first limiting part and the second limiting part of the supplementary limiting structure; when the ladder is opened and overloaded, the first limiting part and the second limiting part of the supplementary limiting structure are mutually abutted and matched; wherein the first and second limiting parts are respectively located on an inner hinge plate 21 and an outer hinge plate 22 hinged to each other in the hinge joint. When climbing personnel or other loads on the ladder, the quality of the climbing personnel or other loads exceeds the locking capacity of the adjusting part to the ladder, when the locking capacity of the adjusting part is exceeded, the adjusting part can break and lose the locking function of the ladder, at the moment, the two pairs of limiting structures are mutually abutted through the first limiting parts and the second limiting parts of the limiting structures, the opening state of the ladder is continuously kept, the ladder is kept in the opening state and is not influenced by the breakage of the adjusting part, the accident of a user is prevented, the safety factor of the ladder is improved, and when the limiting structures are abutted, the gap between the limiting parts is instantly eliminated to generate shaking and sound, the user is reminded that the locking structure is damaged, and the damaged locking structure can be replaced in time. At least one pair of limiting structures in the two pairs of limiting structures are supplementary limiting structures, because the first limiting part in the other limiting structure is the limiting block 23 arranged on the outer side of the inner hinge piece, the second limiting part is the limiting groove 24, the limiting block 23 is an externally attached structure, the strength is low, the instant impact force is difficult to resist, and the long-time independent use is not suitable.

When the ladder is opened without overload, the included angle between the connecting line of the first limiting part and the second limiting part and the hinge point of the inner hinge plate and the outer hinge plate is (0, 1), and when the angle is too large, the gap is large, and when the adjusting piece 31 loses action, the first limiting part and the second limiting part of the limiting structure shake too much in the abutting process, so that operators can fall off directly, and accidents occur.

The first limiting part in the supplementary limiting structure in the limiting structure is a limiting lug 27, and the second limiting part is a lug boss 29; the head of the outer hinge plate 22 is a positioning plate 26, and a gap is formed in the thickness direction of the positioning plate 26; the head part of the inner hinge sheet 21 is provided with a positioning disc 25, and the positioning disc 25 is rotatably arranged in a gap of the positioning disc 26 and is hinged with the positioning disc 26; wherein, the boss 29 is arranged on the outer edge of the positioning disk 25 and extends along the radial direction of the positioning disk 25; the limiting projection 27 is a thick plate fixedly arranged in the gap of the positioning disc 26, and the end surface 27a of the limiting projection 27 is arranged corresponding to the limiting projection 27.

The first limiting part in the other limiting structure is a limiting block 23, and the second limiting part is a limiting groove 24; the outer side of the inner hinge piece 21 is provided with a limiting block 23, and the outer hinge piece 22 is provided with a limiting groove 24 corresponding to the limiting block 23.

The adjusting piece 31 is arranged corresponding to the central shafts of the positioning disc 26 and the positioning disc 25 and is used for locking at least the opening states of the positioning disc 26 and the positioning disc 25; the adjusting piece 31 comprises a handle 32, a hinge shaft 33 arranged on the handle 32 and a pair of second limiting columns 34; wherein, the articulated shaft 33 is arranged along the central shaft direction of the positioning disc 26 and the positioning disc 25; the second limiting columns 34 are respectively arranged on two sides of the hinge shaft 33. The adjusting member 31 further includes an operating portion 39, the operating portion 39 is disposed on the hinge joint 38 and is disposed corresponding to the hinge shaft 33, the operating portion 39 is disposed on the hinge shaft 33 by acting on a second spring 40 sleeved on the hinge shaft 33, so that the second spring 40 is compressed to generate an elastic force acting on the hinge shaft 33, and the hinge shaft 33 drives the second limiting column 34 to perform a displacement at least away from the corresponding through holes of the positioning plate 25 and the rotating plate 26.

A pair of first through holes 35 are formed in the positioning disc 25, and the first through holes 35 are symmetrically arranged on two sides of the central shaft of the positioning disc 25; a pair of second through holes 36 and a pair of third through holes 37 are formed in the positioning plate 26; the second through holes 36 and the third through holes 37 are symmetrically arranged on two sides of the central axis of the positioning plate 26, and the second through holes 36 and the third through holes 37 are alternately arranged around the central axis. When the ladder is opened, the second limiting column 34 is inserted into the first through hole 35 and the second through hole 36 in a contraposition mode or inserted into the first through hole 35 and the third through hole 37 in a contraposition mode.

The locking device is used for locking the inner ladder and the outer ladder and has two states of locking and unlocking. Referring now to FIGS. 1-6: an outer locking hole 6 is formed in the ladder column of the outer ladder 2; a plurality of inner locking holes 5 are formed in the ladder post of the inner ladder 1 corresponding to the outer locking holes 6, and the inner locking holes 5 are arranged at intervals along the length direction of the ladder post of the inner ladder 1; the locking device 7 is fixedly arranged on the ladder post of the outer ladder 2, and the position relation between the inner ladder 1 and the outer ladder 2 is positioned by simultaneously locking the outer locking hole 6 and the inner locking hole 5 at any height position; outer locking hole 6 and interior locking hole 5 all correspond the position setting of footboard on the ladder post separately, like this under the locking state, the footboard of interior outer ladder has increased the area of trampling of combination ladder footboard at the coplanar, has increased the security and the comfort level of climbing.

An inclined support member 20 is arranged between the lowest pedal 4 of the outer ladder 2 and the ladder column, and the middle part of the inclined support member 20 along the length direction is hollow; the middle part of each pedal on the outer ladder 2 along the length direction is hollow; the connecting surface 41 between each pedal on the inner ladder 1 and the ladder column of the inner ladder 1 is polygonal.

The locking device 7 comprises a locking handle 8, two ends of the locking handle 8 are respectively connected with a locking column 9 and a first limiting column 10, the locking column 9 and the first limiting column 10 are arranged in the same direction, wherein the locking column 9 is used for locking the inner ladder and the outer ladder, and the first limiting column 10 is used for keeping the locking handle 8 in an inward movement trend so as to keep the locking column 9 in a locking trend; two ends of the locking handle 8 are respectively bent inwards to form the locking column 9 and the first limiting column 10, so that the strength of the locking handle is increased. Wherein, the middle part of the locking column 9 is provided with a first limit step 18 to limit the depth of the locking column 9 extending into the inner locking hole 5; the middle part of the first limit column 10 is provided with a second limit step 19, which limits the depth of the fourth through hole 14 of the first limit column 10 extending into the end cover 13.

In the locked state, the locking column 9 extends into any one of the inner locking holes 5 on the ladder posts of the inner ladder 1 through the outer locking hole 6 on the ladder post of the outer ladder 2; during the unblock, overcome the effort of first spring 17 outward displacement through operation locking handle 8, order about locking post 9 and first spacing post 10 outward displacement simultaneously, and then make locking post 9 break away from interior locking hole 5 at least to realize the unblock of interior outer ladder.

A cavity 12 is arranged in a pedal 4 on the outer ladder 2, and the cavity 12 is arranged along the length direction of the pedal 4; the end of the pedal 4 is fixedly provided with an end cover 13 which is fastened in a self-adaptive manner and can be expanded through self deformation, such as a first spring expansion piece, a grid piece and the like. Specifically, as shown in fig. 4 and 6, the end cap 13 includes an inner layer and an outer layer, and as seen in a cross-sectional view, the outer layer is an upper portion of the end cap 13, and the inner layer is a lower portion of the end cap 13, the upper portion is a grid structure, each grid can extend along a direction in which the end cap 13 is inserted into the pedal 4, so that the assembly is facilitated, and each grid can be arranged along a direction in which the vertical end cap is inserted into the pedal 4, so that the fastening effect is better and the fastening effect is not easy to pull out. The lower portion is a solid structure, which is a solid body with a certain thickness, and in order to make the thickness of the solid structure thicker and have better effect of resisting external force, the diameters of the first limiting column 10 and the limiting rod 15 can be as small as possible on the premise of ensuring enough use strength. Compared with the prior art that the shell-shaped end cover in the locking mechanism (CN 203394340U) of the telescopic ladder is easy to deform when being subjected to impact force, the damage causes the locking device to fall off, and the ladder frame and the ladder columns lose the supporting function to cause accidents, the end cover in the scheme has a firmer structure and can bear the impact force far greater than the bearing force of the end cover in the prior art; the impact force described herein includes, but is not limited to, various impact forces experienced by the ladder frame and the ladder post during abutment of the supplemental restraint structure against each other in the event of a failure of the adjuster.

The end cover 13 is provided with a fourth through hole 14 for the first limiting column 10 to penetrate through, and the fourth through hole 14 is communicated with the cavity 12.

A limiting rod 15 is extended from the first limiting column 10, the limiting rod 15 is arranged corresponding to the chamber 12, and the free end of the limiting rod 15 is limited in the chamber 12, wherein the limiting rod 15 can be directly formed by extending the first limiting column 10, or the limiting rod 15 and the first limiting column 10 can be two parts respectively, but the two parts are rigidly connected. In order to increase the thickness of the inner solid structure of the end cap 13, the diameter of the limiting rod 15 and the first limiting column 10 can be smaller than that of the locking handle 8, so that the solid thickness can be increased to the maximum extent on the premise of ensuring enough use strength. The limiting rod 15 is sleeved with a first spring 17, the first spring 17 acts between the limiting rod 15 and the pedal 4 to enable the limiting rod 15 to keep a trend of moving towards the inside of the cavity 12, the limiting rod 15 is sleeved with a retaining ring 16, and the first spring 17 acts between the end cover 13 and the retaining ring 16 to enable the limiting rod 15 to keep a trend of moving towards the inside of the cavity 12.

The end cover 13 is fixed on the pedal 4 of the outer ladder 2 through a screw, and the screw is arranged on one surface, far away from the climbing side, of the pedal 4; the screw is combined with the end cover, so that the end cover is more firmly fixed on the pedal.

The operation portion 39 and the second spring 40 mentioned above are conventional technologies, which are known to those skilled in the art and are not innovative in the present application, and therefore, they are not described in detail herein.

Based on the above structure, the specific operation principle of the present invention is described as follows:

when the opening state of the combined ladder needs to be adjusted, the operating part 39 is flapped to move towards the direction close to the hinge shaft 33, the second spring 40 is compressed, the second spring 40 is deformed to generate elastic force to act on the hinge shaft 33, and then the hinge shaft 33 moves away from the direction of the inner hinge piece and the outer hinge piece, so that at least the second limiting column 34 on the handle 32 is driven to be separated from the through hole on the inner hinge piece and the through hole on the outer hinge piece, at the moment, the state of the combined ladder can be adjusted, the handle 32 is rotated, and the second limiting column 34 is simultaneously in aligned splicing with the first through hole 35 and the second through hole 36 or simultaneously in aligned splicing with the first through hole 35 and the third through hole 37. When the ladder was opened and is a word ladder state, if the ladder did not transship, only need adjusting part 31 just can realize the locking to ladder word state, have the clearance between the spacing portion that has at least a pair of limit structure in two pairs of limit structure on the hinge piece this moment, if the ladder transships and surpasss the locking capacity of adjusting part 31 or when leading to adjusting part 31 fracture, two pairs of spacing lugs and spacing recess on the hinge piece will support each other and lean on, continue to keep the word locking state of ladder, prevent that the user from taking place the accident.

When the height of the combined ladder needs to be adjusted, the locking handle 8 is operated to overcome the outward displacement of the acting force of the first spring 17, the locking column 9 and the limiting column 10 are driven to simultaneously move outwards, and then the locking column 9 is at least separated from the inner locking hole 5, so that the unlocking of the inner ladder and the outer ladder is realized, then the inner ladder 1 is adjusted to the corresponding height, the locking handle 8 is rotated to enable the locking column 9 to stretch into the corresponding inner locking hole 5 on the ladder column of the inner ladder 1 through the outer locking hole 6 on the ladder column of the outer ladder 2, and then the locking of the inner ladder state and the outer ladder state is realized, and the height of the combined ladder is adjusted.

The above embodiments are only for illustrating the technical idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention, and not to limit the protection scope of the present invention by this means. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A combination ladder for adjusting and locking the open position of the ladder by means of an adjusting member (31), characterized in that: the ladder comprises a front ladder frame (3) and a rear ladder frame (11), wherein the upper ends of the two ladder frames are hinged through a hinge joint (38), and the two ladder frames respectively comprise an inner ladder (1), an outer ladder (2) and a locking device (7) for locking the inner ladder and the outer ladder;

the hinge joint (38) comprises an inner hinge plate (21) and an outer hinge plate (22) which are assembled in a rotating mode and two pairs of limiting structures;

the two pairs of limiting structures comprise a first limiting part and a second limiting part; at least one pair of limiting structures in the two pairs of limiting structures are supplementary limiting structures; when the ladder is opened and is not overloaded, a gap exists between the first limiting part and the second limiting part of the supplementary limiting structure; when the ladder is opened and overloaded, the first limiting part and the second limiting part of the supplementary limiting structure are mutually abutted and matched;

the first limiting part and the second limiting part are respectively positioned on an inner hinge piece (21) and an outer hinge piece (22) which are hinged with each other in the hinge joint.

2. The combination ladder of claim 1, wherein: when the ladder is opened without overload, the included angle between the first limiting part and the connecting line of the hinge joint of the inner hinge plate and the outer hinge plate and the connecting line of the hinge joint of the second limiting part and the inner hinge plate are (0, 1).

3. The combination ladder of claim 1, wherein: a first limiting part in a supplementary limiting structure in the limiting structure is a limiting lug (27), and a second limiting part is a lug boss (29);

the head part of the outer hinge plate (22) is provided with a positioning disc (26), and a gap is formed in the thickness direction of the positioning disc (26); the head part of the inner hinge sheet (21) is provided with a positioning disc (25), and the positioning disc (25) is rotatably arranged in a gap of the positioning disc (26) and is hinged with the positioning disc (26);

the boss (29) is arranged on the outer edge of the positioning disc (25) and extends along the radial direction of the positioning disc (25); the limiting convex block (27) is a thick plate fixedly arranged in the gap of the positioning disc (26), and the end face (27 a) of the limiting convex block (27) is arranged corresponding to the boss (29).

4. The combination ladder of claim 3, wherein: the adjusting piece (31) is arranged corresponding to the central shafts of the positioning disc (26) and the positioning disc (25) and is used for locking at least the opening states of the positioning disc (26) and the positioning disc (25);

the adjusting piece (31) comprises a handle (32), a hinge shaft (13) arranged on the handle (32) and a pair of second limiting columns (34);

wherein the articulated shaft (13) is arranged along the central shaft direction of the positioning disc (26) and the positioning disc (25); the second limiting columns (34) are respectively arranged on two sides of the hinge shaft (13);

a pair of first through holes (35) is formed in the positioning disc (25), and the first through holes (35) are symmetrically arranged on two sides of a central shaft of the positioning disc (25);

a pair of second through holes (36) and a pair of third through holes (37) are formed in the positioning disc (26); the second through holes (36) and the third through holes (37) are symmetrically arranged on two sides of a central shaft of the positioning disc (26), and the second through holes (36) and the third through holes (37) are alternately arranged around the central shaft;

when the ladder is opened, the second limiting column (34) is in counterpoint insertion with the first through hole (35) and the second through hole (36) or in counterpoint insertion with the first through hole (35) and the third through hole (37) simultaneously.

5. The combination ladder of claim 1, wherein: the four locking devices (7) are respectively arranged corresponding to the inner ladder post and the outer ladder post on the left side of the front ladder frame (3), the inner ladder post and the outer ladder post on the right side of the front ladder frame (3), the inner ladder post and the outer ladder post on the left side of the rear ladder frame (11) and the inner ladder post and the outer ladder post on the right side of the rear ladder frame (11);

the locking device (7) comprises a locking handle (8), two ends of the locking handle (8) are respectively connected with a locking column (9) and a first limiting column (10), and the locking column (9) and the first limiting column (10) are arranged in the same direction;

in a locking state, the locking column (9) extends into any one inner locking hole (5) on the ladder column of the inner ladder (1) through an outer locking hole (6) on the ladder column of the outer ladder (2);

an end cover (13) which can be expanded through self deformation and is fastened in a self-adaptive manner is fixedly arranged at the end part of a pedal (4) on the outer ladder (2), and a fourth through hole (14) for the first limiting column (10) to penetrate through is formed in the end cover (13);

the first spring (17) acts between the first limiting column (10) and the pedal (4) to enable the first limiting column (10) to keep a trend of moving towards the inside of the fourth through hole (14).

6. The combination ladder of claim 5, wherein: the periphery of the end cover (13) comprises a plurality of grids extending along the direction that the end cover (13) is inserted into the pedal (4).

7. The combination ladder of claim 6, wherein: the diameter of the first limiting column (10) is smaller than that of the locking handle (8);

the end cover (13) comprises an inner layer and an outer layer, wherein the inner layer is of a solid structure, and the outer layer is of a grid structure.

8. The combination ladder of claim 6, wherein: a cavity (12) is formed in the pedal (4), and the cavity (12) is arranged along the length direction of the pedal (4); wherein the chamber (12) is in communication with the fourth through-hole (14);

a limiting rod (15) with the diameter not larger than that of the first limiting column (10) extends from the first limiting column (10), the limiting rod (15) is arranged corresponding to the cavity (12), and the free end of the limiting rod (15) is limited in the cavity (12);

the first spring (17) is sleeved on the limiting rod (15), and the first spring (17) acts between the limiting rod (15) and the pedal (4) to enable the limiting rod (15) to keep a trend of moving towards the inside of the cavity (12).

9. The combination ladder of claim 8, wherein: the limiting rod (15) is sleeved with a check ring (16), and the first spring (17) acts between the end cover (13) and the check ring (16) to enable the limiting rod (15) to keep a trend of moving towards the inside of the cavity (12).

10. The combination ladder of claim 5, wherein: the middle part of the locking column (9) is provided with a first limiting step (18) to limit the depth of the locking column (9) extending into the inner locking hole (5);

the middle part of the first limiting column (10) is provided with a second limiting step (19) to limit the depth of the fourth through hole (14) extending into the end cover (13) of the first limiting column (10).