Armrest lock

Abstract

The utility model discloses a handrail lock which comprises a lock shell, an unlocking hook, a pawl, a lock shaft, a ratchet wheel and a limiting piece, the unlocking hook, the pawl, the lock shaft, the ratchet wheel and the limiting piece are arranged in the lock shell, the unlocking hook, the pawl and the lock shaft are all rotationally connected in the lock shell, the ratchet wheel is sleeved and fixedly connected to the lock shaft, the pawl is arranged between the unlocking hook and the ratchet wheel, and the limiting piece is arranged on one side of the ratchet wheel; the lock shaft extends out of the lock shell and is fixedly connected with the handrail, and the axis of the lock shaft is coaxial with the rotating axis of the handrail; a limiting hook is arranged on the pawl; a first limiting tongue and a second limiting tongue are arranged on the ratchet wheel, and the limiting piece is located on a rotating path of the first limiting tongue and the second limiting tongue; when the armrest is folded, the limiting hook is matched with the first limiting tongue to limit the ratchet wheel to rotate towards the opening direction, and the limiting piece is matched with the second limiting tongue to limit the ratchet wheel to rotate towards the folding direction; the unlocking hook is in driving connection with the pawl and used for driving the pawl to rotate away from the ratchet wheel so as to relieve limiting of rotation of the ratchet wheel in the opening direction, and the limiting piece is matched with the first limiting tongue to limit the handrail after the handrail is opened.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of lockset, especially relates to a handrail lock. BACKGROUND

[0002] In the design of automobile seats, the rear central armrest is an important component for improving passenger comfort and convenience, and its stability and reliability are crucial. The armrest lock, as a key device for locking the central armrest of the rear seat of the vehicle, directly affects the use experience and safety of the armrest. The traditional armrest locking method mainly relies on the locking of multiple tooth features of the toothed part. Although this design achieves the basic locking function of the armrest to some extent, it has many shortcomings.

[0003] Firstly, the machining precision of the tooth feature is extremely high. In order to ensure the tightness and stability of the locking, the shape, size and arrangement of each tooth need to be strictly controlled, which undoubtedly increases the difficulty and cost of machining. High-precision machining equipment and complex process flow limit the production efficiency of traditional armrest locks, and also increase the manufacturing cost of the product.

[0004] Secondly, due to the existence of machining errors, the meshing surface between the teeth is often difficult to achieve the ideal state of complete adhesion. This small gap may cause unnecessary rotation of the armrest during locking, affecting the stability of the locking, and may also produce abnormal noise, reducing the passenger's riding experience.

[0005] In addition, the size of the traditional tooth feature is relatively small, which makes it difficult to withstand a large torque load. During vehicle driving, especially when encountering bumpy sections, the armrest may be subjected to a large impact force or torque, and the traditional tooth locking method is often difficult to effectively resist such external forces, resulting in locking failure or damage. INVENTION CONTENTS

[0006] To solve the above problems, the purpose of the utility model is to provide an armrest lock which has low machining precision requirement, lower production cost and can bear larger load.

[0007] To achieve the above-mentioned purpose, the technical scheme of the utility model is as follows:

[0008] An armrest lock, comprising a lock shell and an unlocking hook, a pawl, a lock shaft, a ratchet and a limiting piece arranged in the lock shell, the unlocking hook, the pawl and the lock shaft are all rotationally connected in the lock shell, the ratchet is sleeved and fixedly connected to the lock shaft, the pawl is arranged between the unlocking hook and the ratchet, and the limiting piece is arranged on one side of the ratchet; the lock shaft protrudes from the lock shell and is fixedly connected with the armrest, and the axis of the lock shaft is coaxial with the rotation axis of the armrest.

[0009] The pawl is provided with a limiting hook; the ratchet wheel is provided with a first limiting tongue and a second limiting tongue, and the limiting member is located on the rotation path of the first limiting tongue and the second limiting tongue;

[0010] When the handrail is folded, the limiting hook cooperates with the first limiting tongue to limit the rotation of the ratchet wheel towards the opening direction, and the limiting member cooperates with the second limiting tongue to limit the rotation of the ratchet wheel towards the folding direction;

[0011] The unlocking hook is in driving connection with the pawl, and is used for driving the pawl to rotate away from the ratchet wheel to release the limiting of the rotation of the ratchet wheel towards the opening direction, and the limiting member cooperates with the first limiting tongue to limit the handrail after the handrail is opened.

[0012] According to an embodiment of the utility model, the unlocking hook is provided with an unlocking tongue, and the pawl is provided with an unlocking slot corresponding to the unlocking tongue, and the unlocking tongue is arranged in the unlocking slot;

[0013] When being opened, the unlocking hook is driven to rotate by external force, the unlocking tongue cooperates with the unlocking slot to drive the pawl to rotate away from the ratchet wheel, and the limiting hook is away from the first limiting tongue to release the limiting of the rotation of the ratchet wheel towards the opening direction;

[0014] When the handrail is opened by external force, the lock shaft is driven to rotate, the rotation of the lock shaft drives the rotation of the ratchet wheel, and when the first limiting tongue rotates to cooperate with the limiting member, the ratchet wheel and the handrail are limited.

[0015] According to an embodiment of the utility model, the unlocking hook is provided with an elastic member, and the elastic member gives the pawl elastic force of rotation;

[0016] When being opened, the unlocking hook is driven to rotate by external force overcoming the elastic force, the unlocking tongue cooperates with the first side of the unlocking slot to drive the pawl to rotate away from the ratchet wheel, the limiting hook is away from the first limiting tongue and abuts against the side wall of the ratchet wheel, the side wall of the ratchet wheel limits the limiting hook, and the unlocking tongue abuts against the second side of the unlocking slot by the elastic force;

[0017] When being folded, when the first limiting tongue rotates to be opposite to the limiting hook, the side wall of the ratchet wheel releases the limiting of the limiting hook, and the unlocking tongue drives the pawl and the limiting hook to rotate by the elastic force to make the limiting hook rotate to cooperate with the first limiting tongue.

[0018] According to the utility model one embodiment, the ratchet wheel is provided with a waist-shaped assembly hole, the lock shaft is provided with a waist-shaped assembly part, the cross section shape of the waist-shaped assembly part matches the waist-shaped assembly hole, the ratchet wheel is sleeved on the waist-shaped assembly part through the waist-shaped assembly hole, and the waist-shaped assembly hole is in interference fit with the waist-shaped assembly part.

[0019] According to the utility model one embodiment, the one end outer wall of the lock shell of the lock shaft is provided with a rotation limiting part and a fixed threaded hole in the end face, the handrail is provided with a mounting hole matching the rotation limiting part in shape;

[0020] The rotation limiting part is arranged in the mounting hole, and cooperation thereof can limit the rotation of the lock shaft relative to the handrail; the mounting hole is threaded and connected to the fixed threaded hole through a bolt to fix the lock shaft and the handrail.

[0021] According to the utility model one embodiment, the rotation limiting part comprises two oppositely arranged planes and two oppositely arranged inclined surfaces.

[0022] According to the utility model one embodiment, the limiting piece is a limiting pin, and the limiting pin is fixedly connected with the lock shell.

[0023] According to the utility model one embodiment, the elastic piece is a torsion spring.

[0024] According to the utility model one embodiment, the lock shell comprises a first shell and a second shell, the unlocking hook, the pawl, the ratchet wheel and the limiting piece are arranged between the first shell and the second shell.

[0025] The utility model has the following advantages and positive effects compared with the prior art due to the above technical scheme:

[0026] 1、 the utility model pawl and ratchet wheel adopt limiting hook and first limiting tongue cooperation, compared with the traditional tooth thread cooperation makes the machining precision requirement small, the production cost is lower, the traditional tooth thread cooperation needs high-precision machining to ensure the close meshing between teeth and teeth, and the cooperation mode of limiting hook and first limiting tongue is relatively tolerant, even in the case of certain machining error, stable cooperation effect can be ensured, thereby reducing the production cost.

[0027] Secondly, in the bearing capacity aspect, due to the larger cooperation surface feature of limiting hook and first limiting tongue, the contact area between pawl and ratchet wheel is increased, and then the bearing capacity of the mechanism is improved, and larger load can be carried.

[0028] Moreover, the utility model discloses a ratchet wheel is positioned from two directions to ratchet wheel through pawl and stopper, and effectively eliminates the rotation gap. The traditional toothed cooperation mode is prone to the condition that tooth and tooth cannot be completely attached because of processing error and long -term use wear and tear, causes the rotation gap when folding, and the stability and reliability of mechanism are affected. But the utility model avoids this problem completely, and improves the folding precision and stability of mechanism.

[0029] 2, the utility model ratchet wheel is set on the waist shape assembly part through the waist shape assembly hole, and the waist shape assembly hole and the waist shape assembly part are interference fit, and this assembly structure is lower in the requirement of part processing precision, and is higher in strength, and simple structure is more easily processed, and cancels the welding procedure, and is lower in cost.

[0030] 3, the utility model lock shaft is connected with the handrail through the rotary limiting portion and the mounting hole, so that modularization is realized, and the maintenance cost is reduced. The traditional structure adopts the welding process to weld the connecting sheet metal on the lock shaft and handrail into a welded assembly, and welding needs to purchase welding equipment and special tooling, and if the welded assembly is damaged, then the whole needs to be replaced, and the maintenance cost is high. BRIEF DESCRIPTION OF DRAWINGS

[0031] The specific embodiments of the utility model will be further explained in detail below in combination with the drawings, wherein:

[0032] Figure 1 It is the axonometric drawing of the utility model;

[0033] Figure 2 It is the explosion drawing of the utility model;

[0034] Figure 3 It is the lock shaft and ratchet wheel assembly schematic drawing of the utility model;

[0035] Figure 4 It is the handrail folding state schematic drawing;

[0036] Figure 5 It is the handrail opening process schematic Figure 1 ;

[0037] Figure 6 It is the handrail opening process schematic Figure 2 ;

[0038] Figure 7 It is the handrail folding schematic drawing.

[0039] EXPLANATION OF REFERENCE NUMERALS:

[0040] 1, the first shell; 2, the second shell; 3, the unlocking hook; 4, the unlocking tongue; 5, the unlocking hook pivot; 6, the unlocking hook gasket; 7, the torsion spring; 8, the pawl; 9, the limit hook; 10, the first hollow rivet; 11, the pawl gasket; 12, the ratchet wheel; 13, the lock shaft; 14, the waist-shaped assembly part; 15, the rotation limiting part; 16, the fixed threaded hole; 17, the bearing; 18, the limit pin; 19, the first limit tongue; 20, the second limit tongue; 21, the second hollow rivet; 22, the unlocking slot. DETAILED DESCRIPTION

[0041] The utility model will be explained in further detail below in combination with the drawings and specific embodiments. The advantages and features of the utility model will be more apparent according to the following description. It should be noted that the drawings are all very simplified and all use non-precise ratios, only to facilitate, clear and assist the purpose of explaining the utility model embodiments.

[0042] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the utility model are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), if the specific posture changes, the directional indications will also change accordingly.

[0043] Referring to Figures 1 to 7 The core of the utility model is to provide a handrail lock, including lock shell and set in the unlocking hook 3, pawl 8, lock shaft 13, ratchet wheel 12 and limiting piece in the lock shell, the unlocking hook 3, pawl 8 and lock shaft 13 are all rotationally connected in the lock shell, ratchet wheel 12 is set and fixedly connected to lock shaft 13, pawl 8 is located between the unlocking hook 3 and ratchet wheel 12, and limiting piece is located on one side of ratchet wheel 12.

[0044] Referring to Figure 2The lock shell comprises a first shell 1 and a second shell 2, the unlocking hook 3, the pawl 8, the ratchet wheel 12 and the limiting piece are arranged between the first shell 1 and the second shell 2, and the limiting piece is a limiting pin 18 in the embodiment, and the two ends of the limiting pin 18 are fixedly connected with the first shell 1 and the second shell 2 respectively. The unlocking hook rotating shaft 5 is arranged between the first shell 1 and the second shell 2, the unlocking hook rotating shaft 5 connects the first shell 1 and the second shell 2, the unlocking hook 3 is sleeved and rotationally connected on the unlocking hook rotating shaft 5, and the unlocking hook gasket 6 is further arranged between the unlocking hook 3 and the second shell 2, and the unlocking hook gasket 6 is sleeved on the unlocking hook rotating shaft 5. The first hollow rivet 10 is arranged between the first shell 1 and the second shell 2, the first hollow rivet 10 connects the first shell 1 and the second shell 2, the pawl 8 is sleeved and rotationally connected on the first hollow rivet 10, and the pawl gasket 11 is arranged between the two sides of the pawl 8 and the first shell 1 and the second shell 2 respectively, the pawl gasket 11 is sleeved on the first hollow rivet 10, and the pawl gasket 11 is used for limiting the pawl 8, so that the pawl 8 is prevented from rotating on the shaft. The lock shaft 13 is provided with a bearing 17 between the first shell 1 and the second shell 2 respectively, and the lock shaft 13 penetrates through the two bearings 17. The second hollow rivet 21 is further arranged between the first shell 1 and the second shell 2, and the second hollow rivet 21 is used for connecting the first shell 1 and the second shell 2.

[0045] The pawl 8 is provided with a limiting hook 9, the ratchet wheel 12 is provided with a first limiting tongue 19 and a second limiting tongue 20, the limiting pin 18 is located in the rotating path of the first limiting tongue 19 and the second limiting tongue 20, and the limiting hook 9 and the first limiting tongue 19 can be rotated to cooperate with each other to limit the ratchet wheel 12.

[0046] When the handrail is folded, the limiting hook 9 cooperates with the first limiting tongue 19 to limit the ratchet wheel 12 from rotating towards the opening direction, and the limiting pin 18 cooperates with the second limiting tongue 20 to limit the ratchet wheel 12 from rotating towards the folding direction.

[0047] The unlocking hook 3 is drivingly connected with the pawl 8, and is used for driving the pawl 8 to rotate away from the ratchet wheel 12, so as to release the limitation of the ratchet wheel 12 from rotating towards the opening direction, and the limiting pin 18 cooperates with the first limiting tongue 19 to limit the handrail after the handrail is opened.

[0048] Specifically, the unlocking hook 3 is provided with an unlocking tongue 4, the pawl 8 is provided with an unlocking slot 22 corresponding to the unlocking tongue 4, and the unlocking tongue 4 is arranged in the unlocking slot 22.

[0049] When opening, the unlocking hook 3 is driven to rotate by external force, the unlocking tongue 4 cooperates with the unlocking slot 22 to drive the pawl 8 to rotate away from the ratchet wheel 12, and the limiting hook 9 moves away from the first limiting tongue 19 to release the limitation of the ratchet wheel 12 from rotating towards the opening direction.

[0050] When the handrail is opened by rotating through external force, the lock shaft 13 is driven to rotate, the lock shaft 13 drives the ratchet wheel 12 to rotate, and when the first limiting tongue 19 rotates to cooperate with the limiting pin 18, the ratchet wheel 12 and the handrail are limited.

[0051] The elastic member is provided on the unlocking hook 3, and the elastic member gives the pawl 8 a rotating elastic force; in the embodiment, the elastic member is a torsion spring 7, and the torsion spring 7 is sleeved on the unlocking hook rotating shaft 5.

[0052] When the device is opened, the unlocking hook 3 is driven to rotate by overcoming the elastic force through external force, the unlocking tongue 4 is matched with the first side of the unlocking slot 22 to drive the pawl 8 to rotate away from the ratchet wheel 12, the limiting hook 9 is away from the first limiting tongue 19 and is abutted with the side wall of the ratchet wheel 12, the side wall of the ratchet wheel 12 limits the limiting hook 9, and the unlocking tongue 4 is abutted with the second side of the unlocking slot 22 through the elastic force.

[0053] When the device is folded, when the first limiting tongue 19 rotates to be opposite to the limiting hook 9, the side wall of the ratchet wheel 12 releases the limitation on the limiting hook 9, the unlocking tongue 4 drives the pawl 8 and the limiting hook 9 to rotate through the elastic force, so that the limiting hook 9 is rotated to be matched with the first limiting tongue 19.

[0054] The pawl 8 and the ratchet wheel 12 adopt the limiting hook 9 and the first limiting tongue 19 matched with each other, compared with the traditional tooth pattern cooperation, the processing precision requirement is small, and the production cost is lower, the traditional tooth pattern cooperation needs high-precision processing to ensure the close meshing between teeth, and the cooperation mode of the limiting hook 9 and the first limiting tongue 19 is relatively tolerant, even in the case that there is a certain processing error, stable cooperation effect can be ensured, and therefore the production cost is reduced.

[0055] Secondly, in the bearing capacity aspect, since the cooperation surface features of the limiting hook 9 and the first limiting tongue 19 are relatively large, the contact area between the pawl 8 and the ratchet wheel 12 is increased, and then the bearing capacity of the mechanism is improved, and a larger load can be borne.

[0056] In addition, the pawl 8 and the limiting member limit the ratchet wheel 12 from two directions, and the rotating gap is effectively eliminated. Since the traditional tooth pattern cooperation mode is prone to the situation that teeth cannot be completely attached to each other due to processing errors and long-term use and wear, the rotating gap is caused when the device is folded, and the stability and reliability of the mechanism are affected. The utility model completely avoids the problem, and improves the folding precision and stability of the mechanism.

[0057] Further, the limiting hook 9 and the first limiting tongue 19 are matched in profile, and the cooperation of the limiting hook 9 and the first limiting tongue 19 can make the pawl 8 and the ratchet wheel 12 more tightly meshed.

[0058] The ratchet wheel 12 is provided with a waist-shaped assembly hole, the locking shaft 13 is provided with a waist-shaped assembly part 14, the cross-sectional shape of the waist-shaped assembly part 14 is matched with the waist-shaped assembly hole, the ratchet wheel 12 is sleeved on the waist-shaped assembly part 14 through the waist-shaped assembly hole, and the waist-shaped assembly hole and the waist-shaped assembly part 14 are in interference fit.

[0059] The ratchet wheel 12 is sleeved on the waist-shaped assembly part 14 through the waist-shaped assembly hole, and the waist-shaped assembly hole is in interference fit with the waist-shaped assembly part 14, the assembly structure has lower requirement on the machining precision of parts, higher strength, simple structure, easier machining, and lower cost by canceling the welding process.

[0060] The rotating limiting part 15 is arranged on the outer wall of one end of the lock shell, and the fixed threaded hole 16 is arranged on the end face, and the mounting hole matched with the rotating limiting part 15 is arranged on the handrail.

[0061] Specifically, the rotating limiting part 15 comprises two oppositely arranged planes and two oppositely arranged inclined surfaces.

[0062] The rotating limiting part 15 is arranged on the outer wall of one end of the lock shell, and the fixed threaded hole 16 is arranged on the end face, and the mounting hole matched with the rotating limiting part 15 is arranged on the handrail.

[0063] The working process of the utility model will be further described below:

[0064] Referring to Figure 4 , 5 , 6, in the opening process of the handrail, first of all, the handrail is driven to rotate by overcoming the elastic force of the handrail through the hand-breaking device arranged on the handrail, specifically, the hand-breaking device is connected with the unlocking hook 3 through a steel wire, and the hand-breaking device drives the unlocking hook 3 to rotate by pulling the steel wire to the right.

[0065] The unlocking tongue 4 on the unlocking hook 3 is rotated to cooperate with the first side of the unlocking slot 22 and drive the pawl 8 to rotate away from the ratchet wheel 12, and the limiting hook 9 is away from the first limiting tongue 19, that is, the limiting hook 9 can rotate the ratchet wheel 12 by exceeding the outer edge of the ratchet wheel 12, and then the handrail is rotated and opened by hand, the handrail drives the lock shaft 13 and the ratchet wheel 12 to rotate, and forms a state as shown in Figure 5 At this time, the external force on the hand-breaking device can be removed, the unlocking tongue 4 is in abutment with the second side of the unlocking slot 22 through the elastic force, the unlocking tongue 4 is in abutment with the side wall of the ratchet wheel 12, and the side wall of the ratchet wheel 12 limits the limiting hook 9.

[0066] When the first limiting tongue 19 is rotated to cooperate with the limiting pin 18, the ratchet wheel 12 and the handrail are limited, that is, the handrail is opened to the limit position.

[0067] Referring to Figure 7 , 4In the folding process of the handrail, the handrail is rotated and opened by the hand, the handrail drives the lock shaft 13 and the ratchet wheel 12 to rotate, when the first limiting tongue 19 rotates to be opposite to the limiting hook 9, the side wall of the ratchet wheel 12 releases the limiting of the limiting hook 9, the unlocking tongue 4 drives the ratchet pawl 8 and the limiting hook 9 to rotate by the elastic force, so that the limiting hook 9 rotates to cooperate with the first limiting tongue 19, and meanwhile the limiting pin 18 also cooperates with the second limiting tongue 20.

[0068] The utility model improves the strength of locking mechanism, reduces the manufacturing precision requirement of core part (ratchet wheel 12, ratchet pawl 8), eliminates the rotation gap of lock shaft 13 after locking, cancels the welding procedure, and reduces the cost, optimizes the assembly relationship of lock shaft 13 and handrail connecting sheet metal, cancels the welding procedure, adopts bolt assembly, and the modularization is more convenient to disassemble and assemble, and the maintenance cost is reduced.

[0069] The embodiments of the utility model are described in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments. Even if various changes are made to the utility model, provided that the changes belong to the range of the utility model claims and equivalent technologies, they still fall within the protection scope of the utility model.

Claims

1. A handrail lock characterised in that, The utility model provides a locking device of handrail, including lock shell and be located in the unlocking hook, the pawl, the lock axle, the ratchet wheel and the limiting piece in the lock shell, the unlocking hook, the pawl and the lock axle all are rotatoryly connected in the lock shell, the ratchet wheel is set and is fixedly connected in the lock axle, the pawl is located between the unlocking hook and the ratchet wheel, the limiting piece is located in one side of the ratchet wheel, the lock axle is fixedly connected with the handrail and is projected in the lock shell, and the axis of the lock axle is coaxial with the rotation axis of the handrail, The pawl is equipped with a limiting hook, the ratchet wheel is equipped with a first limiting tongue and a second limiting tongue, and the limiting piece is located in the rotation path of the first limiting tongue and the second limiting tongue, When the handrail is folded, the limiting hook cooperates with the first limiting tongue to limit the rotation of the ratchet wheel towards the opening direction, and the limiting piece cooperates with the second limiting tongue to limit the rotation of the ratchet wheel towards the folding direction, The unlocking hook is drivingly connected with the pawl and is used to drive the pawl to rotate away from the ratchet wheel to release the limitation on the rotation of the ratchet wheel towards the opening direction, and the limiting piece cooperates with the first limiting tongue to limit the handrail after the handrail is opened.

2. The lock according to claim 1, wherein The unlocking hook is equipped with an unlocking tongue, and the pawl is equipped with an unlocking slot corresponding to the unlocking tongue, and the unlocking tongue is located in the unlocking slot, When opened, the unlocking hook is driven to rotate by external force, the unlocking tongue cooperates with the unlocking slot to drive the pawl to rotate away from the ratchet wheel, and the limiting hook is away from the first limiting tongue to release the limitation on the rotation of the ratchet wheel towards the opening direction, When the handrail is rotated and opened by external force, the lock axle is rotated, the rotation of the lock axle drives the rotation of the ratchet wheel, when the first limiting tongue is rotated to cooperate with the limiting piece, the ratchet wheel and the handrail are limited.

3. The lock according to claim 2, wherein The unlocking hook is equipped with an elastic member, and the elastic member gives the pawl a elastic force for rotation, When opened, the unlocking hook is driven to rotate by external force overcoming the elastic force, the unlocking tongue cooperates with the first side of the unlocking slot to drive the pawl to rotate away from the ratchet wheel, the limiting hook is away from the first limiting tongue and abuts against the side wall of the ratchet wheel, the side wall of the ratchet wheel limits the limiting hook, the unlocking tongue abuts against the second side of the unlocking slot by the elastic force, When folded, when the first limiting tongue is rotated to be opposite to the limiting hook, the side wall of the ratchet wheel releases the limitation on the limiting hook, and the unlocking tongue drives the pawl and the limiting hook to rotate by the elastic force, so that the limiting hook is rotated to cooperate with the first limiting tongue.

4. The lock of claim 1, wherein The ratchet wheel is equipped with a waist-shaped assembly hole, the lock axle is equipped with a waist-shaped assembly part, the cross-sectional shape of the waist-shaped assembly part matches the waist-shaped assembly hole, the ratchet wheel is sleeved on the waist-shaped assembly part through the waist-shaped assembly hole, and the waist-shaped assembly hole and the waist-shaped assembly part are in interference fit.

5. The lock of claim 1, wherein The end wall of the lock axle projected out of the lock shell is equipped with a rotation limiting part and a fixed threaded hole on the end face, and the handrail is equipped with a mounting hole matching the rotation limiting part in shape. The rotation limiting part is arranged in the mounting hole and can limit the rotation of the lock shaft relative to the handrail.

6. The lock according to claim 5, wherein The rotation limiting part comprises two oppositely arranged planes and two oppositely arranged inclined surfaces.

7. The lock of claim 1, wherein The limiting part is a limiting pin which is fixedly connected with the lock shell.

8. The lock of claim 3, wherein The elastic part is a torsion spring.

9. The lock of claim 1, wherein The lock shell comprises a first shell and a second shell, and the unlocking hook, the pawl, the ratchet and the limiting part are arranged between the first shell and the second shell.

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