Foldable joint and baby carriage with same

Abstract

The joint comprises a first pivot joint seat, a second pivot joint seat and a third pivot joint seat which are in pivot joint in sequence, one of the first pivot joint seat, the second pivot joint seat and the third pivot joint seat is internally provided with a rail which is communicated end to end, the other pivot joint seat and the third pivot joint seat are respectively provided with a pushing piece, and the pushing pieces are connected with the first pivot joint seat, the second pivot joint seat and the third pivot joint seat. The two pushing pieces extend into different positions of the track respectively, and a driving piece is arranged between the two pushing pieces; when any one of the three rotates, the driving pieces can move along the rails, and the two pushing pieces reversely rotate and move along the rails under the action of the driving pieces, so that the two pushing pieces which are provided with the pushing pieces reversely rotate relative to the one which is provided with the rails, and the joint is switched between the unfolding state and the folding state. In this way, due to the fact that linkage of all the assemblies of the joint is smooth in the unfolding and folding process, unfolding and folding operation of the joint and the baby carriage with the joint is smooth.

Description

Technical Field

[0001] The invention relates to the field of infant products, and in particular to a foldable joint and a baby carriage provided with the joint. Background Art

[0002] As a vehicle for children to ride in, baby strollers are widely used. In order to make it more convenient to use, baby strollers are generally configured to be switchable between an unfolded state and a folded state, so that when it is needed, the baby stroller is in the unfolded state, the child sits in the baby stroller, and the parents push the baby stroller to move; when it is not needed or needs to be carried, the baby stroller can be folded up, because the folded baby stroller is smaller than the unfolded baby stroller and occupies less space.

[0003] A baby stroller is generally made up of multiple components connected together, and the connected components form joints that can be expanded and folded. The linkage of the components during the expansion and folding process of the joints also determines the convenience of the expansion and operation of the baby stroller. If the linkage of the joint components is not good, not only will the linkage of the joints themselves during the expansion and folding process be very unsmooth, resulting in the unsmooth expansion and folding operation; but it will also make the expansion and folding operation of the baby stroller very unsmooth. Summary of the invention

[0004] The object of the present invention is to overcome the above-mentioned shortcomings and provide a foldable joint and a baby stroller provided with the joint, wherein the components of the joint are well linked during the unfolding and folding process, so that the unfolding and folding operations of the joint and the baby stroller provided with the joint are very smooth.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A foldable joint that can be converted between an expanded state and a folded state, the joint comprising a first pivot seat, a second pivot seat, and a third pivot seat that are pivotally connected in sequence, one of the first pivot seat, the second pivot seat, and the third pivot seat is provided with a track that is connected end to end, and the other two are respectively provided with pushing members, the two pushing members respectively extend into different positions of the track, and a driving member is provided between the two pushing members; when any one of the above three rotates, the driving member is driven to move along the track, and the two pushing members rotate and move in the opposite direction along the track under the action of the driving member, so that the two with the pushing members rotate in the opposite direction relative to the one with the track, thereby allowing the joint to be converted between an expanded state and a folded state.

[0007] The track includes a first arc-shaped groove that is not connected end to end and a second arc-shaped groove that is not connected end to end and is arranged outside the first arc-shaped groove, and the two ends of the first arc-shaped groove are respectively connected to the two ends of the second arc-shaped groove, so that the first arc-shaped groove with two connected ends and the second arc-shaped groove together form the track that is connected end to end, and the two pushing members extend into the first arc-shaped groove and the second arc-shaped groove respectively; preferably, one of the tracks is provided with a accommodating space that is not connected end to end, and an arc-shaped protrusion is protruding on the bottom wall of the accommodating space, and there are gaps between the two ends of the arc-shaped protrusion and the two corresponding ends of the accommodating space, so that the accommodating space is located on one side of the protrusion The first arc-shaped groove is located on the other side of the arc-shaped protrusion. The first arc-shaped groove and the second arc-shaped groove are connected through the gaps between the two ends of the arc-shaped protrusion and the corresponding sides of the accommodating space, thereby forming the above-mentioned track that is connected end to end.

[0008] The first pivot seat, the second pivot seat and the third pivot seat rotate through a pivot, and the two pushing members are eccentrically arranged relative to the pivot; preferably, a driving member is arranged between one side of the two pushing members, and a driving member is also arranged between the other sides of the two pushing members; preferably, the driving member is arranged to include a plurality of moving members arranged along a track and movable along the track, and one of the pushing members extends between two adjacent moving members, and the other pushing member extends between another two adjacent moving members.

[0009] One of the tracks is provided with two arc-shaped through holes communicating with the track, the positions of the two arc-shaped through holes respectively correspond to the two pushing members, and the extension directions of the two arc-shaped through holes are respectively the same as the extension directions of the corresponding positions of the track, and the two pushing members respectively extend into the track through the arc-shaped through holes at the corresponding positions; preferably, the two arc-shaped through holes are arranged at intervals, and the two arc-shaped through holes are arranged so that when the two pushing members are respectively located at one end of the two arc-shaped holes, the joint is in an expanded state, and when the two pushing members are respectively located at the other end of the two arc-shaped holes, the joint is in a retracted state.

[0010] The track is arranged in the third pivot seat, and pushing members are respectively arranged on the first pivot seat and the second pivot seat. The pushing member arranged on the first pivot seat is the first pushing member, and the pushing member arranged on the second pivot seat is the second pushing member; the first pushing member passes through the second pivot seat and then extends into the track; preferably, the joint also includes a locking mechanism for limiting the relative rotation of the first pivot seat, the second pivot seat, and the third pivot seat.

[0011] The locking mechanism includes a locking piece that can be relatively axially movably arranged in the joint, and a first elastic piece that is arranged between the locking piece and the first pivot seat; a locking portion is arranged on the locking piece, and the first pivot seat, the second pivot seat, and the third pivot seat are respectively provided with a first matching portion, a second matching portion, and a third matching portion that are matched with the locking portion; under the action of the first elastic piece, the locking portion on the locking piece matches with the first matching portion, the second matching portion, and the third matching portion, and the locking mechanism is in a locked state; the locking piece is moved toward the direction of the first pivot seat, the locking portion on the locking piece is disengaged from the second matching portion and the third matching portion, and the locking mechanism is unlocked; preferably, the locking piece includes a main body and the locking portion arranged on the main body; preferably, a third accommodating cavity is arranged on the side of the third pivot seat facing the second pivot seat, and one side of the main body is located in the third accommodating cavity.

[0012] The first unlocking member is connected to the locking member by a first driving portion and a second driving portion is connected to the locking member by a second driving portion. With the cooperation of a follower part, the locking member moves toward the first pivot seat to unlock the locking device; preferably, the unlocking device also includes a second elastic member arranged between the first unlocking member and the third pivot seat; preferably, the actuating part is located between the two arc-shaped through holes, and an arc-shaped avoidance gap is arranged between the actuating part and the driving part; when the joint is in the expanded state, the arc-shaped avoidance gap makes way for the position of any one of the two second arc-shaped through holes, and the first pushing member or the second pushing member can pass through the arc-shaped avoidance gap and the corresponding arc-shaped through hole in turn and then extend into the track.

[0013] The unlocking device also includes a second unlocking member connected to the third pivot seat and a third elastic member arranged between the second unlocking member and the third pivot seat; under the action of the third elastic member, one side of the second unlocking member extends out of the third pivot seat and the other side extends into the third accommodating cavity; an acting portion is extended toward the bottom wall of the third accommodating cavity on one side of the locking member body, and a second driven portion is arranged on the other side of the second unlocking member toward the direction of the acting portion, and a second active portion cooperating with the second driven portion is arranged toward the direction of the acting portion to move the second unlocking member into the third pivot seat. Through the cooperation of the second active portion and the second driven portion, the locking member is driven to move toward the direction of the first pivot seat to unlock the locking mechanism; preferably, the actuating portion of the first unlocking member is arranged in an annular shape and is relatively rotatably sleeved outside the actuating portion, and the second driven portion is exposed outside the main body; the part of the second unlocking member provided with the second active portion is located between the actuating portion and the bottom wall of the third accommodating cavity.

[0014] A baby carriage comprises a frame which can be switched between an unfolded state and a folded state, wherein the frame comprises the folding joint.

[0015] The frame also includes a rider, a front foot, and a rear foot. The lower end of the rider, the rear end of the front foot, and the front end of the rear foot are respectively connected to the first pivot seat, the second pivot seat, and the third pivot seat.

[0016] The frame includes left and right side brackets, and each side bracket includes the joint and the rider, front legs, and rear legs; the baby carriage also includes a seat, and the two sides of the seat are respectively connected to the two joints.

[0017] The seat is configured to be connected to the third pivot seats of the two side brackets so that both sides can rotate forward and backward relative to each other, and functional parts are provided on both sides of the seat, and the functional parts are configured so that when the seat rotates forward and backward relative to the frame, the functional parts can drive the first unlocking member to rotate or drive the second unlocking member to move downward to unlock the locking mechanism; preferably, when the frame is in the unfolded state, the functional part is located between the first unlocking member and the part of the second unlocking member extending out of the third pivot seat; preferably, the two sides of the seat are respectively connected to a connecting seat so that they can rotate forward and backward relative to each other, and the connecting seat is configured to be connectable to the third pivot seat; preferably, the connecting seat is configured to be detachably connected to the frame in a forward and backward switching manner.

[0018] The beneficial effects of the present invention are:

[0019] 1. Because the first pivot seat, the second pivot seat, and the third pivot seat of the joint of the present invention adopt the linkage rotation mode of the two pushers and the driving member, the linkage of the joint components is very smooth during the unfolding and folding process, so that the unfolding and folding operation of the joint and the baby carriage provided with the joint is very smooth;

[0020] 2. When the frame of the baby stroller of the present invention is to be folded, the locking mechanism can be unlocked directly by driving the first unlocking member or the second unlocking member, or by rotating the seat to drive the first unlocking member or the second unlocking member to move and unlock the locking mechanism; and rotating the seat back and forth relative to the frame can make the seat and the frame rotate relative to each other and fold, and can also unlock the locking mechanism in conjunction, thereby making the overall folding operation of the baby stroller of the present invention simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional schematic diagram of the baby carriage frame of the present invention in an unfolded state;

[0022] Figure 2 Based on Figure 1 A magnified schematic diagram of part A;

[0023] Figure 3 Based on Figure 1 An enlarged schematic diagram of another angle of part A;

[0024] Figure 4 Based on Figure 1 A magnified diagram of the explosion of part A;

[0025] Figure 5 Based on Figure 1 A magnified diagram of the explosion at another angle of part A;

[0026] Figure 6 is an enlarged schematic diagram of the track in the joint of the present invention;

[0027] Figure 7 It is an enlarged schematic diagram showing the track, the driving member and the two pushing members in the joint of the present invention in one state;

[0028] Figure 8 It is an exploded and enlarged schematic diagram of the third pivot seat of the joint of the present invention;

[0029] Fig. 9 It is an enlarged schematic diagram of the combination of the third pivot seat of the joint of the present invention and the first unlocking member and the second unlocking member;

[0030] Fig.10 It is an enlarged schematic diagram showing the track, the driving member and the two pushing members in the joint of the present invention when the frame is in the folded state;

[0031] Fig.11 It is a plan view of the baby carriage frame of the present invention in a folded state;

[0032] Fig.12 It is an enlarged schematic diagram of the combination of the third pivot seat of the joint of the present invention, the first unlocking member and the locking member;

[0033] Fig.13 is an enlarged schematic diagram of a joint locking member of the present invention;

[0034] Fig.14 It is an enlarged schematic diagram of the combination of the second pivot seat, the third pivot seat and the locking member of the joint of the present invention;

[0035] Fig.15 Based on Figure 3 A schematic diagram of the cross section enlarged along the BB direction;

[0036] Fig.16 It is an enlarged schematic diagram of the cooperation between the locking member, the first unlocking member, and the second unlocking member of the joint of the present invention;

[0037] Fig.17 It is a three-dimensional schematic diagram of a baby stroller frame of the present invention after being connected to a seat and the seat is arranged forward;

[0038] Fig.18 It is a three-dimensional schematic diagram of the baby stroller frame and the seat after being separated from each other according to the present invention. DETAILED DESCRIPTION

[0039] like Figures 1 to 11 As shown, the present invention discloses a foldable joint, which can be converted between an expanded state and a folded state. The joint includes a first pivot seat 1, a second pivot seat 2, and a third pivot seat 3 which are pivotally connected in sequence. Among the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3, one of the three is provided with a track 31 which is connected end to end, and the other two are respectively provided with pushing members 11 and 21, the two pushing members 11 and 21 are respectively extended into different positions of the track 31, and a driving member 4 is provided between the two pushing members 11 and 21; when any one of the above three rotates, the driving member 4 is driven to move along the track 31, and the two pushing members 11 and 21 rotate and move in the opposite direction along the track 31 under the action of the driving member 4, so that the two with the pushing members rotate in the opposite direction relative to the one with the track 31, thereby enabling the joint to be converted between the expanded state and the folded state.

[0040] Specifically, if one of the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 is provided with a pusher and rotates to one side relative to the one provided with the track 31, the corresponding pusher will rotate and move along the track 31 to one side, and the pusher rotating and moving along the track 31 will push the driving member 4 to move along the track 31, so that the other pusher will be pushed by the moving driving member 4 and rotate along the track 31 to the other side, that is, the two pushers 11 and 21 rotate and move in opposite directions along the track 31 (such as Figure 7 , 10The rotation direction indicated by the arrow in the middle) causes the one provided with the other pusher to rotate to the opposite side relative to the one provided with the track 31, so that the joint is switched between the expanded state and the folded state. If the one provided with the track 31 rotates relative to the other two, the driving member 4 will rotate along with the track 31, but because the two pushers extend into the track 31, the movement of the driving member 4 will inevitably interact with the two pushers 11 and 21, so that there will be relative movement between the driving member 4 and the track 31, that is, the driving member 4 will move along the track 31, and then the two pushers 11 and 21 will also rotate in the opposite direction due to the relative movement of the driving member 4 and the track 31, so that the two provided with the pushers will still rotate toward the one provided with the track 31, so that the joint is switched between the expanded state and the folded state.

[0041] The track 31 includes a first arc groove 311 that is not connected to the end and a second arc groove 312 that is not connected to the end and is arranged outside the first arc groove 311, and the two ends of the first arc groove 311 are respectively connected to the two ends of the second arc groove 312 (such as Figure 6 As shown), the first arc groove 311 and the second arc groove 312 connected at both ends together form the end-to-end track 31, and the two pushers 11 and 21 extend into the first arc groove 311 and the second arc groove 312 respectively (as shown in FIG. Figure 7 In this way, the two pushers 11 and 21 are both extended into the track 31 and are located at different positions.

[0042] In the present embodiment, it is equivalent to that one of the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 is provided with a track 31 and is provided with a accommodating space that is not connected at both ends. An arc-shaped protrusion 33 is protruded on the bottom wall of the accommodating space, and there are gaps 331 and 332 between the two ends of the arc-shaped protrusion 33 and the two corresponding ends of the accommodating space 32, so that the accommodating space 32 is located on one side of the protrusion with the first arc-shaped groove 311, and is located on the other side of the arc-shaped protrusion 33 with the second arc-shaped groove 312. The first arc-shaped groove 311 and the second arc-shaped groove 312 are connected through the gaps 331 and 332 at the two ends of the arc-shaped protrusion 33 and the corresponding sides of the accommodating space 32, thereby forming the above-mentioned track 31 that is connected at both ends.

[0043] The first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 rotate through a pivot 5, and the two pushers 11, 21 are eccentrically arranged relative to the pivot 5, that is, the two pushers 11, 21 are not on the same straight line as the pivot 5. The first arc groove 311 is arranged around the pivot 5, and the second arc groove 312 is also arranged around the pivot 5. Because the two pushers 11, 21 are eccentrically arranged relative to the pivot 5, the first arc groove 311 and the second arc groove 312 are not arc grooves centered on the pivot 5, but are arranged to be arcs that match the rotation trajectory of the two pushers 11, 21. In this way, when any one of the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 rotates with the pivot 5 as the rotation axis, the two with the pushers 11, 21 can rotate and move in the opposite direction relative to the other.

[0044] A driving member 4 is arranged between the two pushing members 11 and 21, that is, a driving member 4 is arranged between one side of the two pushing members 11 and 21, and a driving member 4 is also arranged between the other sides of the two pushing members 11 and 21, so that no matter in which direction one of the two pushing members 11 and 21 rotates along the track 31, the driving member 4 on the relevant side can push the other pushing member to rotate in the opposite direction along the track 31.

[0045] In this embodiment, the driving member 4 is configured to include a plurality of moving members 41 arranged along the track 31 and movable along the track 31, and one of the pushing members 11 extends between two adjacent moving members 41, and another pushing member 21 extends between another two adjacent moving members 41. That is, a plurality of moving members 41 are arranged between one side of the two pushing members 11, 21, and a plurality of moving members 41 are also arranged between the other sides of the two pushing members 11, 21, thereby achieving the purpose of providing a driving member 4 between one side of the two pushing members 11, 21 and providing a driving member 4 between the other sides.

[0046] Preferably, among the multiple moving members 41 between any one side of the two pushers 11, 21, two adjacent moving members 41 are in contact with each other. With such a configuration, when any pusher rotates and moves along the track 31 to one side, the moving members 41 on the side of the pusher can be synchronously pushed and moved along the track 31, thereby synchronously pushing the other pusher to rotate and move in the opposite direction along the track 31. In this way, the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 can rotate synchronously relative to each other, thereby realizing the linkage folding / expanding of the joint more quickly.

[0047] The moving member 41 can be configured as any known and feasible moving member 41 that can smoothly move along the track 31, such as a ball, a cylindrical moving member 41 or a circular moving member 41.

[0048] In other embodiments, the driving member 4 between any one side of the two pushing members 11, 21 can also be set to be any other suitable integral driving member 4 that can move along the track 31. It can also be a driving member 4 composed of the above-mentioned multiple moving members 41 set between one side of the two pushing members 11, 21, or it can be the above-mentioned integral driving member 4.

[0049] like Figure 5 As shown, one of the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3, which is provided with the track 31, is provided with two arc-shaped through holes 34, 35 communicating with the track 31. The positions of the two arc-shaped through holes 34, 35 correspond to the two pushers 11, 21, respectively, and the extension directions of the two arc-shaped through holes 34, 35 are respectively the same as the extension directions of the corresponding positions of the track 31. The two pushers 11, 21 extend into the track 31 through the arc-shaped through holes 34, 35 at the corresponding positions. That is, an arc-shaped through hole 33 is provided at the corresponding position of the first arc-shaped groove 311, and an arc-shaped through hole 34 is also provided at the corresponding position of the second arc-shaped groove 312. Therefore, when the two pushers 11, 21 rotate and move along the track 31, they also rotate and move along the arc-shaped through holes 34, 35 at the same time.

[0050] The two arc-shaped through holes 34 and 35 are arranged at intervals. Preferably, the two arc-shaped through holes 34 and 35 are arranged so that when the two pushers 11 and 21 are respectively located at one end of the two arc-shaped holes 34 and 35, the joint is in an extended state, and when the two pushers 11 and 21 are respectively located at the other end of the two arc-shaped holes 34 and 35, the joint is in a closed state. That is, when the joint is in an extended state, the two pushers 11 and 21 are respectively located at one end of the two arc-shaped holes 34 and 35 (such as Fig. 9 As shown); during the folding process, the two pushers 11, 21 rotate and move in opposite directions along the two arc-shaped through holes 34, 35 and the track 31 at the corresponding position respectively. When the two pushers 11, 21 rotate and move to the other end of the two arc-shaped through holes 34, 35 respectively, the two pushers 11, 21 can no longer continue to rotate and move in this direction, which means that the joint is already in the folded state and no longer needs to be rotated. The operation from the folding process to the unfolded state is the same. With such a setting, the operator can intuitively know that the joint has been folded / expanded, which makes the folding / expanding operation of the joint of the present invention more intuitive.

[0051] Among the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3, the second pivot seat 2 located in the middle may be provided with the track 31, and the pivot seats on both sides are respectively provided with pushing members toward the second pivot seat 2; or the first pivot seats 1 or the third pivot seats 3 on both sides are provided with the track 31, and the second pivot seat 2 and the third pivot seat 3 or the first pivot seat 1 are provided with the pushing members.

[0052] Combination Figure 8 , 9 As shown, one of the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3, which is provided with the track 31, includes a relatively fixedly connected base 36 and a fixing member 37, and the track 31 is formed between the base 36 and the fixing member 37. Such a configuration facilitates the installation of the driving member 4 and the third pivot seat 3.

[0053] In this embodiment, the track 31 is disposed in the third pivot seat 3, that is, the third pivot seat 3 includes a base 36 and a fixing member 37 that are relatively fixedly connected. Pushing members are respectively disposed on the first pivot seat 1 and the second pivot seat 2. The pushing member disposed on the first pivot seat 1 is the first pushing member 11, and the pushing member disposed on the second pivot seat 2 is the second pushing member 21; the first pushing member 11 passes through the second pivot seat and then extends into the track 31.

[0054] Combined with Figures 12 to 16 As shown, the joint further includes a locking mechanism for limiting the relative rotation of the first pivot seat 1 , the second pivot seat 2 , and the third pivot seat 3 .

[0055] In this embodiment, the locking mechanism includes a locking member 6 which is relatively axially movable in the joint, and a first elastic member 60 which is arranged between the locking member 6 and the first pivot seat 1; a locking portion is arranged on the locking member 6, and the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 are respectively provided with a first matching portion 12, a second matching portion 22, and a third matching portion 30 which are matched with the locking portion; under the action of the first elastic member 60, the locking portion on the locking member 6 matches with the first matching portion 12, the second matching portion 22, and the third matching portion 30, and the locking mechanism is in a locked state, the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 cannot rotate relative to each other, and the joint is locked in an expanded state. Move the locking member 6 toward the direction of the first pivot seat 1, and the locking portion on the locking member 6 disengages from the second matching portion 22 and the third matching portion 30 and only matches with the first matching portion 12, and the locking mechanism is unlocked, so that the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 can rotate relative to each other, the joint can be folded, and the first pivot seat 1 rotates together with the locking member 6.

[0056] In this embodiment, the second pivot seat 2 is provided with an axially penetrating through hole 20; the locking member 6 includes a body 61 and the locking portion provided on the body 61, the locking portion includes a first locking portion 62 extending outward from the periphery of the body 61, and a second locking portion 63 extending from the first locking portion 62 toward one side of the third pivot seat 3, so that the second locking portion 63 is spaced apart from the body 61, and the outer edge of the first locking portion 62 protrudes outside the outer edge of the second locking portion 63, and the body 61 and the second locking portion 63 can move axially along the through hole 20 of the second pivot seat 2 The first matching portion 12 and the second matching portion 22 are respectively the first locking groove 12 and the second locking groove 22 arranged on the opposite sides of the first pivot seat 1 and the second pivot seat 2; the third matching portion 30 is the third locking groove 30 arranged on the side of the third pivot seat 3 facing the second pivot seat 2; when the joint is in the unfolded state, under the action of the first elastic member 60, the part of the first locking portion 62 protruding outside the outer edge of the second locking portion 63 is simultaneously inserted into the first locking groove 12 and the second locking groove 22, and the side of the second locking portion 63 away from the first locking portion 62 is inserted into the third locking groove 30. In this way, the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 cannot rotate relative to each other, the locking mechanism is in the locked state, and the joint is locked in the unfolded state.

[0057] The outer periphery of the body 61 of the locking member 6 is provided with an avoidance recess 610 at a corresponding position, so that a channel for the first pusher to pass through is formed between the avoidance recess 610 and the wall of the through hole 20, and the first pusher 11 extends into the track 31 after passing through the channel. When the locking mechanism is unlocked, when the first pivot seat 1 rotates, the first pusher 11 and the locking member 6 can rotate together, that is, the avoidance recess 610 and the first pusher 11 maintain a relatively unchanged positional relationship, thereby avoiding interference during the folding and unfolding process.

[0058] The third pivot seat 3 is provided with a third accommodating cavity 38 on one side facing the second pivot seat 2, and one side of the body 61 is located in the third accommodating cavity 38. In this embodiment, the third matching portion, i.e., the third locking groove 30, is located on the cavity wall of the third accommodating cavity 38 and communicates with the third accommodating cavity 38. Such a configuration can make the matching between the locking member 6 and the third pivot seat 3 more stable.

[0059] Preferably, the first pivot seat 1 is provided with a first accommodating cavity 13 on one side facing the second pivot seat 2, the first locking groove 12 is located on the cavity wall of the first accommodating cavity 13 and communicates with the first accommodating cavity 13; the other side of the body 61 (i.e., the side facing the first pivot seat 1) extends into the first accommodating cavity 13. In this way, the cooperation between the locking member 6 and the first pivot seat 1 is more stable.

[0060] The arc-shaped through holes 34 , 35 are disposed on the bottom wall of the third accommodating cavity 38 , and the track 31 is disposed on a side of the bottom wall of the third accommodating cavity 38 that is away from the second pivot seat 2 .

[0061] In the present invention, an unlocking device is further provided between the joint and the locking member 6 for driving the locking member 6 to move and unlock the locking mechanism.

[0062] Combination Figure 3 , 4 As shown in Figures 5 and 13, the unlocking device includes a first unlocking member 7 which is rotatably connected to the third pivot seat 3. The first unlocking member 7 includes a driving portion 71 and an actuating portion 72 which is relatively fixedly connected to one side of the driving portion 71. The other side 710 of the driving portion 71 extends out of the third pivot seat 3. The actuating portion 72 is located in the third accommodating cavity 38 and is opposite to one side of the locking member body 61. The actuating portion 72 and the body 61 are respectively provided with a first active portion 721 and a first driven portion 611 which match each other on opposite sides. The first unlocking member 7 is rotated, and through the cooperation of the first active portion 721 and the first driven portion 611, the locking member 6 moves toward the first pivot seat 1 to unlock the locking device. Specifically, after the locking member 6 moves a certain distance in the direction of the first pivot seat 1, its first locking portion 62 disengages from the second locking groove 22 and completely enters the first locking groove 12, and the second locking portion 63 disengages from the third locking groove 30. The locking mechanism is unlocked, and the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 can rotate relative to each other.

[0063] In this embodiment, the first active part 721 can be set as a boss, the first driven part 611 can be set as a groove, and the sides of the boss and the groove can be set as inclined surfaces, so that when the first locking member 6 rotates, the boss and the inclined surface of the groove can be matched to push the locking member 6 to move in the direction of the first pivot seat 1. In other embodiments, the first active part 721 and the first driven part 611 can also be set as other structures that can match, such as two circles of teeth that can mesh with each other, or two circles of wavy surfaces that can match. The first active part 721 and the first driven part 611 can also be set as other known and feasible structures that can achieve the above purpose.

[0064] The third accommodating cavity 38 has a long arc-shaped through hole 381 (such as Figure 3 The driving portion 71 extends out of the third pivot seat 3 through the arc-shaped long through hole 381 and can rotate along the arc-shaped long through hole 381, so that the rotation of the first unlocking member 7 will not be interfered.

[0065] Combination Figure 4 , 5As shown in FIGS. 9 and 10 , the actuating portion 72 is located between the two arc-shaped through-holes 34 and 35, and an arc-shaped avoidance gap 73 is provided between the actuating portion 72 and the driving portion 71; when the joint is in the unfolded state, the arc-shaped avoidance gap 73 clears the position of any one of the two second arc-shaped through-holes 34 and 35, and the first pushing member 11 or the second pushing member 21 can sequentially pass through the arc-shaped avoidance gap 73 and the corresponding arc-shaped through-hole and then extend into the track 31. Because the actuating portion 72 is located between the two arc-shaped through-holes, only one of the arc-shaped through-holes will be covered when the driving portion 71 is connected to the actuating portion 72, so the arc-shaped avoidance gap 73 only needs to clear the covered arc-shaped through-hole.

[0066] With such arrangement, no matter the joint is in the expanded state or the folded state or in the folding / expanding process, the first unlocking member 7 will not interfere with the two pushing members 11 and 21 to affect the folding and expanding of the joint.

[0067] The unlocking device further includes a second elastic member 70 disposed between the first unlocking member 7 and the third pivot seat 3. When the first unlocking member 7 is rotated, the second elastic member 70 is subjected to pressure; after the first unlocking member 7 is released, the first unlocking member 7 is reset under the action of the restoring force of the second elastic member 70.

[0068] Preferably, the unlocking device also includes a second unlocking member 8 which is relatively movably connected to the third pivot seat, and a third elastic member 80 arranged between the second unlocking member 8 and the third pivot seat 3; an action portion 64 is provided on one side of the locking member body 61 extending toward the bottom wall of the third accommodating chamber 38, and a second follower portion 641 is provided on the side of the action portion 64 facing the bottom wall of the third accommodating chamber 38; under the action of the third elastic member 80, one side of the second unlocking member 8 extends out of the third pivot seat 3, and the other side extends into the third accommodating chamber 38, and the other side of the second unlocking member 8 is provided with a second active portion 81 cooperating with the second follower portion 641 in the direction of the action portion 64; the second unlocking member 8 is moved into the third pivot seat 3, and through the cooperation of the second active portion 81 and the second follower portion 641, the locking member 6 is driven to move in the direction toward the first pivot seat 1 to unlock the locking mechanism.

[0069] The side wall of the third accommodating cavity 38 is provided with a through hole 380, and one side of the second unlocking member 8 extends out of the third pivot seat 3 through the through hole 380. In this embodiment, a supporting portion 390 is convexly provided on the bottom wall of the third accommodating cavity 38, and a long slot is provided on the second unlocking member 8, and the supporting portion 390 penetrates into the long slot, and the second active portion 81 is provided on the part of the second unlocking member 8 located on the side of the supporting portion 390 away from the through hole 380; the third elastic member 80 is provided in the long slot, and the third elastic member 80 is configured as a compression spring, and one end of the third elastic member 80 is in contact with the supporting portion 390, and the other end is in contact with one end of the long slot away from the supporting portion 390. Therefore, under the action of the third elastic member 80, the second unlocking member 8 maintains a tendency to move out of the third pivot seat 3.

[0070] The second driven portion 641 and the second active portion 81 may be configured as a second driven inclined surface and a second driven inclined surface that match each other.

[0071] When it is necessary to fold the joint in the unfolded state, the first unlocking member 7 can be rotated, and the first unlocking member 7 cooperates with the first active portion 721 and the first driven portion 611 on the locking member body 61, so that the locking member 6 moves toward the first pivot seat 1 to unlock the locking mechanism; the second unlocking member 8 can also be moved into the third accommodating cavity 38, and the second unlocking member 8 cooperates with the second active portion 81 and the second driven portion 641 on the opposite side of the locking member 6, so that the locking member 6 is pushed toward the first pivot seat 1 to unlock the locking mechanism.

[0072] The actuating portion 72 of the first unlocking member 7 is annular and relatively rotatably sleeved outside the action portion 64, and the second driven portion 641 is exposed outside the main body; the second unlocking member 8 is provided with a second active portion 81, which is located between the actuating portion 72 and the bottom wall of the third accommodating chamber 38. In this way, the first unlocking member 7 and the second unlocking member 8 do not interfere with each other. When the first unlocking member 7 is rotated, the first unlocking member 7 does not move, and when the second unlocking member 8 is moved, the first unlocking member 7 does not move.

[0073] The first unlocking member 7 and the second unlocking member 8 are provided to make the unlocking operation more convenient. In other embodiments, only one of the first unlocking member 7 and the second unlocking member 8 may be provided.

[0074] The outer periphery of the body 61 of the locking member 6 may be provided with only one first locking portion 62 and one second locking portion 63, or multiple first locking portions 62 may be provided at intervals. When multiple first locking portions 62 are provided, at least one first locking portion 62 is provided with a second locking device; the number of the first locking grooves 12, the second locking grooves 22 and the third locking grooves 30 is provided correspondingly. In this embodiment, multiple first locking portions 62 are provided at intervals at the outer periphery of the body 61, and the second locking portion 63 is provided on one of the first locking portions 62. In this way, the third accommodating cavity 38 is more convenient for the arrangement of the first unlocking member 7 and the second unlocking member 8.

[0075] The present invention further discloses a baby carriage, which comprises a frame 400 that can be switched between an unfolded state and a folded state, and the frame 400 comprises the folding joint mentioned above.

[0076] The frame 400 also includes a rider 100, a front foot 200, and a rear foot 300. The lower end of the rider 100, the rear end of the front foot 200, and the front end of the rear foot 300 are respectively connected to the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3. Figure 1 When the baby stroller is folded, the locking mechanism is unlocked by driving the first unlocking member 7 to rotate or the second unlocking member 8 to move, so that the handle 100 can be rotated backward and downward toward the rear foot 300 (i.e., clockwise), driving the first pivot seat 1 to rotate synchronously, so that the first pusher 11 rotates and moves along the track 31, and pushes the driving member 4 to move along the track 31, and the moving driving member 4 pushes the second pusher to rotate in the opposite direction (i.e., rotate counterclockwise) along the track 31. The rotation and movement directions of the two pushers 11 and 21 are as shown in FIG. Figure 7 Thus, the front leg 200 connected to the second pivot seat 2 also rotates counterclockwise, that is, rotates and moves backward toward the direction of the rear leg 300. When the rider 100 can no longer rotate, the rider 100 and the front leg 200 are relatively close to the rear leg 300, and the baby stroller is folded (such as Fig.11 When the baby carriage is in the folded state, the positions of the first pushing member 11 and the second pushing member 21 are as shown in FIG. Fig.10 shown.

[0077] When the folded baby stroller is to be unfolded, the operation is reversed. That is, the handle 100 is rotated upward, thereby driving the first pusher 11 to rotate and move along the track 31, and pushing the driving member 4 to move along the track 31, and the moving driving member 4 pushes the second pusher to rotate in the opposite direction along the track 31. The rotational movement directions of the two pushers 11 and 21 are as follows: Fig.10As shown by the middle arrow; the front foot 200 connected to the second pivot seat 2 rotates forward. When the rider 100 and the front foot 200 rotate to a certain angle, under the action of the first elastic member 60, the locking member 6 is locked with the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3, so that the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 cannot rotate relative to each other, and the crib is locked in the unfolded state.

[0078] In this embodiment, when the joint / stroller is in the unfolded state, the first pusher 11 and the second pusher 12 are connected. Figure 7 In other embodiments, when the joint is in the expanded state, Figure 7 Reference numeral 12 in the figure refers to a first pusher disposed on the first pivot seat 1. Figure 7 The reference numeral 11 in the figure refers to a second pusher disposed on the second pivot seat 2, that is, Figure 7 The positions of the first pusher 11 and the second pusher 21 are interchanged, so that when the joint / stroller is folded, when the handle 100 / the first pivot seat 1, 21 is rotated clockwise, the first pusher 11 is rotated clockwise, thereby pushing the second pusher 11 to rotate counterclockwise through the driving member 4 (same as the present invention). Figure 7 In this way, the first pivot seat 1 and the second pivot seat 2 also rotate in the opposite direction relative to the third pivot seat 3, that is, the joint is folded, that is, the rider 100 and the front foot 200 are moved in the direction of the rear foot 300 to fold. In another embodiment, when the joint is in the unfolded state, the first pusher 11 and the second pusher 21 are in the Fig.10 In the position shown in FIG. 1 , when the joint / stroller is folded, when the handle 100 / first pivot seat 1 is rotated clockwise, the first pusher 11 rotates clockwise, thereby pushing the second pusher 21 to rotate counterclockwise (as shown in FIG. 1 ). Fig.10 The direction indicated by the arrow in the middle), that is, the joints are folded, that is, the rider 100 and the front leg 200 are moved in the direction of the rear leg 300 and the baby carriage is folded.

[0079] As described above, the first pushing member 11 and the second pushing member 21 can be respectively arranged at different positions of the first pivot seat 1 and the second pivot seat 2, so that when the joint is in the unfolded state, the positions where the first pushing member 11 and the second pushing member extend into the track 31 are also different, as long as the above-mentioned functions can be achieved.

[0080] In this embodiment, the frame 400 includes left and right side brackets 500, each side bracket 500 includes the joint and the rider 100, the front foot 200, and the rear foot 300; the baby carriage also includes a seat 600, and the two sides of the seat 600 are respectively connected to the two joints. Preferably, the seat 600 is configured to be connected to the third pivot seat 3 of the two side brackets 500 so that the two sides can rotate relative to each other forward and backward, and the two sides of the seat 600 are provided with a functional part 601, and the functional part is configured, and when the seat 600 rotates forward and backward relative to the frame 400, the functional part 601 can drive the first unlocking member 7 to rotate or drive the second unlocking member 8 to move downward to unlock the locking mechanism.

[0081] That is, when the frame 400 of the baby carriage of the present invention is to be folded, the locking mechanism can be unlocked directly by driving the first unlocking member 7 or the second unlocking member 8 to move, or by rotating the seat 600 to drive the first unlocking member 7 to rotate or the second unlocking member 8 to move.

[0082] Preferably, when the frame 400 is in the unfolded state, the functional portion 601 is located between the first unlocking member 7 and the second unlocking member 8 extending outside the joint (i.e., extending outside the third pivot seat 3), and when the seat 600 rotates forward and backward relative to the frame 400, the function can drive the first unlocking member 7 to rotate or drive the second unlocking member 8 to move downward to unlock the locking mechanism.

[0083] Preferably, both the front and rear sides of the functional part 601 are set as inclined surfaces, so that when the seat 600 rotates relative to the frame 400 toward the direction where the second unlocking member 8 is located, the inclined surface on the corresponding side of the functional part 601 can make it easier for the second unlocking member 8 to move downward.

[0084] In this embodiment, preferably, the seat 600 can be directly connected to the two third pivot seats 3 of the frame 400 so as to be rotatable relative to each other forward and backward, or the two sides of the seat 600 are respectively connected to a connecting seat 602 so as to be rotatable relative to each other forward and backward, and the connecting seat 602 is configured to be connectable to the third pivot seat 3, so that after the connecting seat 602 is connected to the frame 400, the seat 600 can rotate relative to the connecting seat 602 forward and backward, that is, it can also rotate relative to the frame 400 forward and backward.

[0085] In this embodiment, the connecting seat 602 is configured to be detachably connected to the frame 400 in a forward-backward reversible manner, that is, after the connecting seat 602 is connected to the seat 600, it can be removed from the frame 400 and then connected to the frame 400 after reversing the forward-backward direction relative to the frame 400. By such a configuration, the seat 600 that is rotatably connected to the connecting seat 602 relative to the forward-backward direction also realizes the function of reversing the forward-backward direction relative to the frame 400. Regardless of whether the seat 600 is set forward or backward, the driving part 71 is located between the first unlocking member 7 and the second unlocking member 8 that extend out of the joint (third pivot seat), that is, regardless of whether the seat 600 is set forward or backward, the rotation of the seat 600 can at least drive one of the first unlocking member 7 and the second unlocking member 8, that is, the rotation of the seat 600 relative to the frame 400 can unlock the locking mechanism.

[0086] The seat 600 rotates relative to the frame 400, and the angle between the seat 600 and the frame 400 also decreases, that is, the seat 600 and the frame 400 are relatively folded; and the rotation of the seat 600 relative to the frame 400 can also unlock the locking mechanism. In other words, the seat 600 can be rotated back and forth relative to the frame 400 so that the seat 600 and the frame 400 can be relatively rotated and folded, and the locking mechanism can also be unlocked in conjunction, thereby making the overall folding operation of the baby stroller of the present invention simpler.

[0087] A seat locking mechanism is provided between the seat 600 and the frame 400 to limit the relative rotation of the two. After unlocking the seat locking mechanism, the seat 600 can be rotated relative to the frame 400. The specific structure of the connection, locking, and unlocking of the seat 600 and the frame 400 is not the inventive point of the present invention, and can be any known and feasible structure, such as the relevant descriptions of the Chinese patent "A seat for a baby stroller and a baby stroller with the seat" (patent number 2018210926414, application date July 10, 2018) and the Chinese patent "A baby stroller with convenient seat disassembly and assembly" (patent number 2018210926151, application date July 10, 2018), so it will not be described in detail here.

[0088] In summary, because the first pivot seat 1, the second pivot seat 2, and the third pivot seat 3 of the joint of the present invention adopt the linkage rotation method of the two pushing members 11, 21 and the driving member 4, the joint and the components of the baby stroller provided with the joint are smoothly linked during the unfolding and folding process, so that the unfolding and folding operations are very simple and convenient.

[0089] The front lower portion of the front leg 200 is connected to the front wheel 201 , and the rear lower portion of the rear leg 300 is connected to the rear wheel 300 .

[0090] Those skilled in the art should understand that the directions or positional relationships indicated by terms such as "up, down, left, right, front, back, inside, outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

Claims

1. A foldable joint, which can be switched between an extended state and a folded state, characterized in that: The joint includes a first pivot seat, a second pivot seat, and a third pivot seat which are pivotally connected in sequence. Among the first pivot seat, the second pivot seat, and the third pivot seat, one of them is provided with a track which is connected end to end, and the other two are respectively provided with a pushing member, and the two pushing members respectively extend into different positions of the track, and a driving member is provided between the two pushing members; when any one of the above three rotates, the driving member is driven to move along the track, and the two pushing members rotate and move in the opposite direction along the track under the action of the driving member, so that the two with the pushing members rotate in the opposite direction relative to the one with the track, thereby making the joint switch between the expanded state and the folded state.

2. The foldable joint according to claim 1, characterized in that: The track includes a first arc-shaped groove that is not connected end to end and a second arc-shaped groove that is not connected end to end and is arranged outside the first arc-shaped groove, and the two ends of the first arc-shaped groove are respectively connected to the two ends of the second arc-shaped groove, so that the first arc-shaped groove with two connected ends and the second arc-shaped groove together form the track that is connected end to end, and the two pushing members extend into the first arc-shaped groove and the second arc-shaped groove respectively; preferably, one of the tracks is provided with a accommodating space that is not connected end to end, and an arc-shaped protrusion is protruding on the bottom wall of the accommodating space, and there are gaps between the two ends of the arc-shaped protrusion and the two corresponding ends of the accommodating space, so that the accommodating space is located on one side of the protrusion The first arc-shaped groove is located on the other side of the arc-shaped protrusion. The first arc-shaped groove and the second arc-shaped groove are connected through the gaps between the two ends of the arc-shaped protrusion and the corresponding sides of the accommodating space, thereby forming the above-mentioned track that is connected end to end.

3. The foldable joint according to claim 1 or 2, characterized in that: The first pivot seat, the second pivot seat and the third pivot seat rotate through a pivot, and the two pushing members are eccentrically arranged relative to the pivot; preferably, a driving member is arranged between one side of the two pushing members, and a driving member is also arranged between the other sides of the two pushing members; preferably, the driving member is arranged to include a plurality of moving members arranged along a track and movable along the track, and one of the pushing members extends between two adjacent moving members, and the other pushing member extends between another two adjacent moving members.

4. The foldable joint according to any one of claims 1 to 3, characterized in that: One of the tracks is provided with two arc-shaped through holes communicating with the track, the positions of the two arc-shaped through holes respectively correspond to the two pushing members, and the extension directions of the two arc-shaped through holes are respectively the same as the extension directions of the corresponding positions of the track, and the two pushing members respectively extend into the track through the arc-shaped through holes at the corresponding positions; preferably, the two arc-shaped through holes are arranged at intervals, and the two arc-shaped through holes are arranged so that when the two pushing members are respectively located at one end of the two arc-shaped holes, the joint is in an expanded state, and when the two pushing members are respectively located at the other end of the two arc-shaped holes, the joint is in a retracted state.

5. The foldable joint according to any one of claims 1 to 4, characterized in that: The track is arranged in the third pivot seat, and pushing members are respectively arranged on the first pivot seat and the second pivot seat. The pushing member arranged on the first pivot seat is the first pushing member, and the pushing member arranged on the second pivot seat is the second pushing member; the first pushing member passes through the second pivot seat and then extends into the track; preferably, the joint also includes a locking mechanism for limiting the relative rotation of the first pivot seat, the second pivot seat, and the third pivot seat.

6. The foldable joint according to claim 5, characterized in that: The locking mechanism includes a locking piece that can be relatively axially movably arranged in the joint, and a first elastic piece that is arranged between the locking piece and the first pivot seat; a locking portion is arranged on the locking piece, and the first pivot seat, the second pivot seat, and the third pivot seat are respectively provided with a first matching portion, a second matching portion, and a third matching portion that are matched with the locking portion; under the action of the first elastic piece, the locking portion on the locking piece matches with the first matching portion, the second matching portion, and the third matching portion, and the locking mechanism is in a locked state; the locking piece is moved toward the direction of the first pivot seat, the locking portion on the locking piece is disengaged from the second matching portion and the third matching portion, and the locking mechanism is unlocked; preferably, the locking piece includes a main body and the locking portion arranged on the main body; preferably, a third accommodating cavity is arranged on the side of the third pivot seat facing the second pivot seat, and one side of the main body is located in the third accommodating cavity.

7. The foldable joint according to claim 6, characterized in that: The first unlocking member is connected to the locking member by a first driving portion and a second driving portion is connected to the locking member by a second driving portion. With the cooperation of a follower part, the locking member moves toward the first pivot seat to unlock the locking device; preferably, the unlocking device also includes a second elastic member arranged between the first unlocking member and the third pivot seat; preferably, the actuating part is located between the two arc-shaped through holes, and an arc-shaped avoidance gap is arranged between the actuating part and the driving part; when the joint is in the expanded state, the arc-shaped avoidance gap makes way for the position of any one of the two second arc-shaped through holes, and the first pushing member or the second pushing member can pass through the arc-shaped avoidance gap and the corresponding arc-shaped through hole in turn and then extend into the track.

8. The foldable joint according to claim 7, characterized in that: The unlocking device also includes a second unlocking member connected to the third pivot seat and a third elastic member arranged between the second unlocking member and the third pivot seat, under the action of the third elastic member, one side of the second unlocking member extends out of the third pivot seat and the other side extends into the third accommodating cavity; an acting portion is extended toward the bottom wall of the third accommodating cavity on one side of the locking member body, and a second driven portion is arranged on the other side of the second unlocking member toward the direction of the acting portion, and a second active portion cooperating with the second driven portion is arranged toward the direction of the acting portion, so as to move the second unlocking member into the third pivot seat. Through the cooperation of the second active portion and the second driven portion, the locking member is driven to move toward the direction of the first pivot seat to unlock the locking mechanism; preferably, the actuating portion of the first unlocking member is arranged in an annular shape and is relatively rotatably sleeved outside the actuating portion, and the second driven portion is exposed outside the main body; the part of the second unlocking member provided with the second active portion is located between the actuating portion and the bottom wall of the third accommodating cavity.

9. A baby stroller comprising a frame that can be switched between an unfolded state and a folded state, characterized in that: The frame comprises a folding joint as claimed in any one of claims 1 to 8.

10. The baby carriage support according to claim 9, characterized in that: The frame also includes a rider, a front foot, and a rear foot, and the lower end of the rider, the rear end of the front foot, and the front end of the rear foot are respectively connected to the first pivot seat, the second pivot seat, and the third pivot seat; preferably, the frame includes left and right side brackets, and each side bracket includes the joints and the rider, the front foot, and the rear foot; the baby carriage also includes a seat, and the two sides of the seat are respectively connected to the two joints; preferably, the seat is configured to be connected to the third pivot seat of the two side brackets so that the two sides can rotate relative to each other forward and backward, and functional parts are provided on both sides of the seat, and the functional parts It is configured that, when the seat rotates forward and backward relative to the frame, the functional part can drive the first unlocking member to rotate or drive the second unlocking member to move downward to unlock the locking mechanism; preferably, when the frame is in the unfolded state, the functional part is located between the first unlocking member and the part of the second unlocking member extending outside the third pivot seat; preferably, the two sides of the seat are respectively connected to a connecting seat so as to be rotatable forward and backward relative to each other, and the connecting seat is configured to be connectable to the third pivot seat; preferably, the connecting seat is configured to be detachably connected to the frame in a forward and backward switching manner.

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