CN113276929B

CN113276929B - Baby carriage

Info

Publication number: CN113276929B
Application number: CN202110466443.XA
Authority: CN
Inventors: 吉跃; 理查德·迈克尔·巴斯蒂安
Original assignee: Goodbaby Child Products Co Ltd
Current assignee: Goodbaby Child Products Co Ltd
Priority date: 2021-02-04
Filing date: 2021-04-28
Publication date: 2022-08-02
Anticipated expiration: 2041-04-28
Also published as: CN113276929A; CN215322800U

Abstract

The invention relates to a baby carrier with a foldable frame, wherein the frame comprises a front push rod and a rear push rod which are positioned at two sides, the front push rod is rotationally connected with the rear push rod, the baby carrier comprises a push rod locking mechanism for rotationally locking the front push rod and the rear push rod, an operating mechanism for locking and unlocking the push rod locking mechanism, and a transmission rod piece for connecting the push rod locking mechanism with the operating mechanism, and when the operating mechanism is rotated, the operating mechanism pushes the transmission rod piece to move to one side close to the push rod locking mechanism and unlocks the push rod locking mechanism. The push rod locking mechanism is arranged to keep the frame stable in the unfolding state, the operating mechanism and the transmission rod assembly are arranged, the unlocking and locking switching of the push rod locking mechanism can be simply and labor-saving realized, the operating locking mechanism in the operating mechanism can lock the operating mechanism, the push rod locking mechanism is prevented from being unlocked due to misoperation, and multiple locking is formed by the mutual matching of a plurality of mechanisms and assemblies.

Description

Baby carriage

Technical Field

The invention relates to a baby carriage.

Background

Collapsible carts, such as collapsible strollers, may be collapsed to reduce the size of the cart, thereby facilitating storage and transport of the cart when not in use.

In order to keep the buggy stable during use, the buggy is usually provided with a locking mechanism which is locked in the use position and unlocked and thus folded when not in use.

The locking mechanism of current bassinet needs both hands to control the unblock, and is very inconvenient, and locking release mechanism is comparatively complicated, takes place the loss easily, need provide simple but durable solution, and this solution is suitable for the shallow of different grade type, is the perambulator very much.

Disclosure of Invention

The invention aims to provide a baby carriage.

In order to achieve the purpose, the invention adopts the technical scheme that:

a baby carriage comprises a frame in an unfolded state and a folded state, a front wheel assembly and a rear wheel assembly, wherein the front wheel assembly and the rear wheel assembly are connected with the frame, the frame comprises side brackets which are respectively positioned at two sides, each side bracket comprises a front push rod, a rear push rod, a first bracket and a second bracket, the rear end part of each front push rod is rotatably connected with the front end part of each rear push rod, one end part of each first bracket is rotatably connected with the corresponding front push rod, one end part of each second bracket is rotatably connected with the corresponding rear push rod, the other end part of each first bracket, the other end part of each second bracket and two parts in the rear wheel assembly are connected, the third part is connected with any one of the two parts, or the three parts are connected with each other,

the baby carrier also comprises a push rod locking mechanism for rotationally locking the front push rod and the rear push rod, an operating mechanism for operating the push rod locking mechanism to switch between a locking state and an unlocking state, and a transmission rod assembly arranged between the push rod locking mechanism and the operating mechanism, wherein the push rod locking mechanism is arranged between the front push rod and the rear push rod on the same side, the transmission rod assembly comprises a transmission rod piece, the transmission rod piece is provided with a first end part and a second end part which are respectively arranged at the two ends of the transmission rod piece in the length extension direction, the first end part of the transmission rod piece is matched with the push rod locking mechanism, the second end part of the transmission rod piece is matched with the operating mechanism, and the operating mechanism can rotate relative to the transmission rod piece,

when the operating mechanism is rotated, the operating mechanism drives the transmission rod piece to move between the push rod locking mechanism and the operating mechanism and unlocks the push rod locking mechanism.

Preferably, the operating mechanism is located between the push rod locking mechanisms on both sides, and when the operating mechanism is rotated, the operating mechanism simultaneously drives the transmission rod pieces on both sides to move from the operating mechanism to the push rod locking mechanisms and unlocks the push rod locking mechanisms.

Preferably, the operating mechanism comprises a rotatable operating member and an operating locking assembly for rotationally locking the operating member, and the operating member is matched with the second end part of the transmission rod.

Further preferably, the operation locking assembly comprises an operation lock cylinder arranged on the operation member, and an operation unlocking member movably connected to the operation member, wherein the operation unlocking member has a first inclined surface, and one end of the operation lock cylinder has a second inclined surface in sliding fit with the first inclined surface; the transmission rod component also comprises a transmission rod sleeve, the transmission rod sleeve is sleeved on the transmission rod piece,

when the operation locking component is in a locking state: the other end of the operating lock cylinder is positioned in the transmission rod sleeve; when the operational locking assembly is in the unlocked state: the other end of the operating lock cylinder is separated from the transmission rod sleeve; when the operation unlocking piece is pressed, the first inclined surface slides relative to the second inclined surface, and the operation locking assembly is switched between the locking state and the unlocking state.

Still further preferably, the operating mechanism further includes a first elastic member for giving an elastic restoring force to the operation unlocking member and a second elastic member for giving an elastic restoring force to the operation key cylinder, the first elastic member is disposed between the operation unlocking member and the operating member, and the second elastic member is disposed between the operation key cylinder and the operating member.

Preferably, the operating mechanism is provided with a spiral groove, the second end of the transmission rod extends into the spiral groove, and when the operating mechanism is rotated: the spiral groove drives the transmission rod piece to move between the push rod locking mechanism and the operating mechanism.

Preferably, the driving rod assembly further comprises a third elastic member for giving an elastic restoring force to the driving rod member, and the third elastic member is disposed between the driving rod member and the push rod locking mechanism.

Preferably, the push rod locking mechanism includes a first joint member, a second joint member relatively rotatable with the first joint member, and a push rod lock cylinder, the first joint member is connected to one of the front push rod and the rear push rod, the second joint member is connected to the other of the front push rod and the rear push rod, the first joint member is disposed between the second joint member and the transmission rod member, the first joint member has a first joint lock groove, the second joint member has a second joint lock groove, a first end of the transmission rod member abuts against an end of the push rod lock cylinder, and when the push rod locking mechanism is in a locked state, the push rod lock cylinder is simultaneously located in the first joint lock groove and the second joint lock groove; when the push rod locking mechanism is in an unlocking state: the push rod lock core moves towards the second joint lock groove and is separated from the first joint lock groove.

Preferably, the first joint lock groove is provided with a through hole, and the first end of the transmission rod passes through the through hole and abuts against one end of the push rod lock core.

Further preferably, the push rod locking mechanism further comprises a fourth elastic element giving an elastic restoring force to the push rod lock cylinder, and the fourth elastic element is arranged between the push rod lock cylinder and the second joint lock groove.

Further preferably, one side of the first joint member is provided with an installation groove, and the other end of the driving rod assembly is inserted into the installation groove.

Preferably, the frame further comprises a mounting rod, and the operating mechanism and the transmission rod assembly are arranged on the mounting rod.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

the invention can keep the frame stable in the unfolding state by arranging the push rod locking mechanism at the rotating folding position of the folding frame, and then arranging the operating mechanism and the transmission rod assembly, the unlocking and locking switching of the push rod locking mechanism can be simply and laborsavingly realized, the operating locking mechanism in the operating mechanism can lock the operating mechanism, and the unlocking of the push rod locking mechanism caused by misoperation is avoided, so that the danger is caused, multiple locking is formed by the mutual matching of a plurality of mechanisms and assemblies, the unfolding state of the frame is more stable and safer, and meanwhile, the unlocking of the frame is more laborsaving through multiple transmission.

Drawings

FIG. 1 is a perspective view of the stroller in this embodiment with the frame in an expanded position;

FIG. 2 is a side view of the stroller in this embodiment with the frame in an expanded position;

FIG. 3 is a cross-sectional view of the cross-section A-A of FIG. 2;

FIG. 4 is a perspective view of the stroller in this embodiment, with the frame in an intermediate position between an extended position and a collapsed position;

FIG. 5 is a side view of the stroller in this embodiment in an intermediate position between the deployed and folded positions;

FIG. 6 is a cross-sectional view of the cross-section B-B of FIG. 5;

FIG. 7 is a perspective view of the stroller in this embodiment with the frame in a folded position;

FIG. 8 is a side view of the stroller in this embodiment with the frame in a collapsed position;

FIG. 9 is a schematic perspective view of the push rod locking mechanism, the operating mechanism, the transmission rod assembly and the mounting rod of the present embodiment;

FIG. 10 is a disassembled elevational view of the push rod locking mechanism, operating mechanism, drive rod assembly and mounting rod of the present embodiment.

In the above drawings: 11. a front push rod; 12. a rear push rod; 13. a first bracket; 14. a second bracket; 15. a front wheel assembly; 16. a rear wheel assembly; 21. an operating member; 211. a helical groove; 22. operating the unlocking member; 221. a first inclined plane; 23. operating the lock cylinder; 231. a second inclined plane; 24. a first elastic member; 25. a second elastic member; 31. a driving rod member; 32. a drive rod sleeve; 33. a third elastic member; 41. a first joint member; 411. a first knuckle keyway; 412. a through hole; 413. mounting grooves; 42. a second joint member; 421. a second knuckle lock groove; 43. a push rod lock cylinder; 44. a fourth elastic member; 5. and (5) installing a rod.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, 2, 4, 5, 7, and 8, a stroller, such as a stroller, includes a frame having an unfolded state and a folded state, a front wheel assembly 15 and a rear wheel assembly 16 connected to the frame, the frame includes side brackets respectively located at two sides, the side brackets include a front push rod 11, a rear push rod 12, a first bracket 13, and a second bracket 14, the front ends of the front push rods 11 at two sides are connected to the front wheel assembly 15, in this embodiment, one front wheel assembly 15 is provided, the rear end of the front push rod 11 is rotatably connected to the front end of the rear push rod 12 at the same side, and the rear push rods 12 at two sides are connected to each other through a transverse connecting rod integrally provided with the front push rod; one end of the first bracket 13 is rotatably connected with the same-side front push rod 11, one end of the second bracket 14 is rotatably connected with the same-side rear push rod 12, the other end of the first bracket 13 and the other end of the second bracket 14 on the same side are both connected with the rear wheel assembly 16, or the other end of the first bracket 13 on the same side is connected with the rear wheel assembly 16, the other end of the second bracket 14 is connected with the first bracket 13, or the other end of the second bracket 14 on the same side is connected with the rear wheel assembly 16, and the other end of the first bracket 13 is connected with the second bracket 14. In the present embodiment, the stroller is a three-wheeled stroller, and when the frame is placed on a flat ground in the unfolded state, one end of the first bracket 13 is an upper end thereof, and the other end thereof is a lower end thereof, and one end of the second bracket 14 is an upper end thereof, and the other end thereof is a lower end thereof.

As shown in fig. 3, 6, 9 and 10, the stroller further includes a push-bar lock mechanism for rotationally locking the front push-bar 11 and the rear push-bar 12, an operating mechanism for operating the push-bar lock mechanism to switch between a locked state and an unlocked state, a transmission-bar assembly provided between the push-bar lock mechanism and the operating mechanism, and the mounting bar 5. The front push rod 11 and the rear push rod 12 are rotatably connected through push rod locking mechanisms connected with the front push rod and the rear push rod, the mounting rod 5 is arranged between the push rod locking mechanisms on the two sides, and the transmission rod assembly and the operating mechanism are arranged on the mounting rod 5. The transmission rod assembly comprises a transmission rod sleeve 32 fixedly arranged on the mounting rod 5 and a transmission rod piece 31 movably arranged in the transmission rod sleeve 32, the transmission rod piece 31 is provided with a first end part and a second end part which are respectively arranged at two ends of the transmission rod piece in the length extension direction, the first end part of the transmission rod piece 31 is matched with the push rod locking mechanism, and the second end part of the transmission rod piece 31 is matched with the operating mechanism. The operating mechanism is only provided with one and is located in the middle of the installation rod 5, the two sides of the operating mechanism are both provided with a transmission rod component and a push rod locking mechanism, the operating mechanism rotates around the installation rod 5, the rotating direction is as shown in figure 1, the operating mechanism can push the transmission rod components 31 at the two sides to move towards the two sides, the transmission rod components 31 move towards the direction of the push rod locking mechanism close to the same side, the push rod locking mechanism is unlocked after the transmission rod components 31 move, the unfolding state of the frame is unlocked, the frame can be folded, and the push rod locking mechanism is in the unlocking state when the frame is folded and folded. In this embodiment, when the frame is unfolded and placed on a flat ground, the left-hand side is left, the right-hand side is right, the first end of the left-side transmission rod member 31 is located on the left and the second end is located on the right, the first end of the right-side transmission rod member 31 is located on the right and the second end is located on the left, the left-side transmission rod member 31 is moved leftward to unlock the left-side push rod locking mechanism, and the right-side transmission rod member 31 is moved rightward to unlock the right-side push rod locking mechanism.

In the present embodiment, the operating mechanism includes an operating member 21 (i.e., a hand grip seat), and an operation locking assembly provided on the operating member 21, the operating member 21 is engaged with the operating member 21, the operating member 21 is rotated, the operating member 21 pushes the transmission link 31 to move toward the push-bar locking mechanism, the operation locking assembly is used to lock and unlock the rotation of the operating member 21, and the operating member 21 can start rotating only after the operating member 21 is unlocked by the operation locking assembly.

The operation locking assembly includes an operation unlocking piece 22 (i.e., a pressing knob) and an operation key cylinder 23, which are inserted on the operation piece 21, and the pressing operation unlocking piece 22 (pressing direction perpendicular to the axial direction of the mounting rod 5) pushes the operation key cylinder 23 to move, thereby unlocking the rotation of the operation piece 21. When the operation locking component locks the operation piece 21, the other end part of the operation lock core 23 is inserted into the transmission rod sleeve 32, and the operation piece 21 and the transmission rod sleeve 32 are both provided with grooves for inserting the operation lock core 23; when the unlocking member 22 is operated to unlock the operating member 21, the operating key 23 is moved further into the operating member 21, and the other end portion of the operating key 23 is moved out of the lever sleeve 32. The operating member 21 has a first inclined surface 221, one end of the operating key 23 has a second inclined surface 231 matched with the first inclined surface, when the unlocking member 22 is pressed, the first inclined surface 221 and the second inclined surface 231 are matched and slide, so that the operating key 23 moves towards the direction vertical to the pressing direction, and the other end of the operating key 23 moves out of the transmission rod sleeve 32. The operating mechanism further includes a first elastic member 24 and a second elastic member 25, in this embodiment, springs are used, the first elastic member 24 is connected between the operation unlocking member 22 and the operating member 21, the first elastic member 24 always gives an elastic force for resetting and bouncing the pressed operation unlocking member 22, the second elastic member 25 is connected between the operation key cylinder 23 and the operating member 21, the second elastic member 25 always gives an elastic force for resetting the operation key cylinder 23 (so that the other end of the operation key cylinder 23 is inserted back into the transmission rod sleeve 32), and a blocking portion is provided between the operation unlocking member 22 and the operating member 21 to prevent the operation unlocking member 22 from bouncing out of the operating member 21 after being reset.

The operating member 21 is provided with a spiral groove 211, the second end of the transmission rod 31 penetrates through the transmission rod sleeve 32 and then is inserted into the spiral groove 211, the spiral direction of the spiral groove 211 is arranged along the rotating direction of the operating member 21, the depth of the spiral groove 211 is gradually deepened along the rotating direction, and when the operating member 21 rotates, the second end of the transmission rod 31 moves from the deeper groove to the shallower groove, so that the operating member 21 pushes the transmission rod 31 to move to one side of the push rod locking mechanism.

The push rod locking mechanism comprises a first joint part 41, a second joint part 42 and a push rod lock core 43. The first joint member 41 and the second joint member 42 are rotatably connected, one of the first joint member 41 and the second joint member 42 is connected with the front push rod 11, the other one of the first joint member 41 and the second joint member 42 is connected with the rear push rod 12 (in this embodiment, the first joint member 41 is connected with the rear end of the front push rod 11, and the second joint member 42 is connected with the front end of the rear push rod 12), the first joint member 41 is arranged between the transmission rod assembly and the second joint member 42, one side of the first joint member 41 connected with the transmission rod assembly is provided with a mounting groove 413, and the other end of the transmission rod assembly and the end of the mounting rod 5 are inserted into the mounting groove 413 and connected with the mounting groove 413. The driving rod assembly further includes a third elastic member 33, in this embodiment, a spring is used, the third elastic member 33 is connected between the driving rod 31 and the mounting groove 413, and the third elastic member 33 always gives an elastic force for resetting the driving rod 31 (moving the first end of the driving rod 31 away from the push rod locking mechanism). The first joint member 41 has a first joint locking groove 411 on the side connected to the second joint member 42, and the second joint member 42 has a second joint locking groove 421 on the side connected to the first joint member 41. When the push rod locking mechanism is in a locked state, the push rod lock cylinder 43 is simultaneously positioned in the first joint lock groove 411 and the second joint lock groove 421, so that the first joint part 41 and the second joint part 42 cannot relatively rotate, and the frame is in an unfolded state; when the push rod locking mechanism is in the unlocked state, the push rod lock cylinder 43 moves out of the first joint lock slot 411, and the first joint member 41 and the second joint member 42 can rotate relatively. The first end of the driving rod 31 abuts against one end of the push rod lock cylinder 43, and when the operating member 21 pushes the driving rod 31 to move towards the side of the push rod locking mechanism, the first end of the driving rod 31 pushes the push rod lock cylinder 43, so that one end of the push rod lock cylinder 43 moves outwards until moving out of the first joint lock slot 411. The first joint member 41 is provided with a through hole 412, the mounting groove 413 is communicated with the first joint locking groove 411 through the through hole 412, and the second end of the transmission rod member 31 passes through the through hole 412 to abut against the push rod lock core 43. The push rod locking mechanism further includes a fourth elastic member 44, which is a spring in this embodiment, the fourth elastic member 44 is connected between the push rod lock cylinder 43 and the second joint member 42, and the fourth elastic member 44 always gives an elastic force for restoring the push rod lock cylinder 43 (inserting one end portion of the push rod lock cylinder 43 back into the first joint lock groove 411).

The working principle of the present embodiment is specifically described as follows:

when the frame is in an unfolding state, the unlocking piece 22 is pressed to operate, the unlocking piece 22 and the operation lock cylinder 23 are matched to unlock the operation piece 21, then the operation piece 21 is rotated, the operation piece 21 and the transmission rod piece 31 are matched to push the transmission rod piece 31, the pushed transmission rod piece 31 moves to one side of the push rod locking mechanism, the transmission rod piece 31 pushes the push rod lock cylinder 43 to unlock the push rod locking mechanism, the frame can be folded from the unfolding state to the folding state, and when the frame is unfolded from the folding state to the unfolding state, the first elastic piece 24, the second elastic piece 25, the third elastic piece 33 and the fourth elastic piece 44 release elastic force, and all parts are reset and reset to the locking state.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. 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 baby carriage, comprising a frame with an unfolded state and a folded state, a front wheel assembly and a rear wheel assembly connected with the frame, wherein the frame comprises side brackets respectively positioned at two sides, each side bracket comprises a front push rod, a rear push rod, a first bracket and a second bracket, the rear end part of the front push rod is rotatably connected with the front end part of the rear push rod, one end part of the first bracket is rotatably connected with the front push rod, one end part of the second bracket is rotatably connected with the rear push rod, the other end part of the first bracket, the other end part of the second bracket and two parts in the rear wheel assembly are connected, a third part is connected with any one of the two parts, or the three parts are connected with each other, and the baby carriage is characterized in that:

the baby carrier also comprises a push rod locking mechanism for rotationally locking the front push rod and the rear push rod, an operating mechanism for operating the push rod locking mechanism to switch between a locking state and an unlocking state, and a transmission rod assembly arranged between the push rod locking mechanism and the operating mechanism, wherein the push rod locking mechanism is arranged between the front push rod and the rear push rod on the same side, the transmission rod assembly comprises a transmission rod piece, the transmission rod piece is provided with a first end part and a second end part which are respectively arranged at two ends of the transmission rod piece in the length extension direction, the first end part of the transmission rod piece is matched with the push rod locking mechanism, the second end part of the transmission rod piece is matched with the operating mechanism, the operating mechanism can rotate relative to the transmission rod piece, and the operating mechanism comprises a rotatable operating piece, The operation locking assembly is used for locking the operation piece in a rotating mode, the operation piece is matched with the second end part of the transmission rod piece, the operation locking assembly comprises an operation lock core arranged on the operation piece and an operation unlocking piece movably connected to the operation piece, the operation unlocking piece is provided with a first inclined surface, and one end part of the operation lock core is provided with a second inclined surface in sliding fit with the first inclined surface;

2. A stroller according to claim 1, wherein: the operating mechanism is positioned between the push rod locking mechanisms on the two sides, and when the operating mechanism is rotated, the operating mechanism simultaneously drives the transmission rod pieces on the two sides to move from the operating mechanism to the push rod locking mechanisms and unlocks the push rod locking mechanisms.

3. A stroller according to claim 1, wherein: the transmission rod component also comprises a transmission rod sleeve, the transmission rod sleeve is sleeved on the transmission rod piece,

4. A stroller according to claim 3, wherein: the operating mechanism further comprises a first elastic piece giving elastic resetting force to the operation unlocking piece and a second elastic piece giving elastic resetting force to the operation lock cylinder, the first elastic piece is arranged between the operation unlocking piece and the operating piece, and the second elastic piece is arranged between the operation lock cylinder and the operating piece.

5. A stroller according to claim 1, wherein: the operating mechanism is provided with a spiral groove, the second end part of the transmission rod piece extends into the spiral groove, and when the operating mechanism is rotated: the spiral groove drives the transmission rod piece to move between the push rod locking mechanism and the operating mechanism.

6. A stroller according to claim 1, wherein: the transmission rod assembly further comprises a third elastic piece giving elastic resetting force to the transmission rod piece, and the third elastic piece is arranged between the transmission rod piece and the push rod locking mechanism.

7. A stroller according to claim 1, wherein: the push rod locking mechanism comprises a first joint part, a second joint part and a push rod lock core, wherein the second joint part can rotate relative to the first joint part, the first joint part is connected to one of the front push rod and the rear push rod, the second joint part is connected to the other of the front push rod and the rear push rod, the first joint part is arranged between the second joint part and the transmission rod piece, the first joint part is provided with a first joint locking groove, the second joint part is provided with a second joint locking groove, the first end part of the transmission rod piece is abutted against one end part of the push rod lock core, and when the push rod locking mechanism is in a locking state, the push rod lock core is simultaneously positioned in the first joint locking groove and the second joint locking groove; when the push rod locking mechanism is in an unlocking state: the push rod lock core moves towards the second joint lock groove and is separated from the first joint lock groove.

8. A stroller according to claim 7, wherein: the first joint locking groove is provided with a through hole, and the first end part of the transmission rod piece penetrates through the through hole to be abutted against one end part of the push rod lock core.

9. A stroller according to claim 7, wherein: the push rod locking mechanism further comprises a fourth elastic piece giving elastic resetting force to the push rod lock cylinder, and the fourth elastic piece is arranged between the push rod lock cylinder and the second joint lock groove.