Pivot joint, seat frame, seat reversing mechanism and stroller

Abstract

A pivot joint, a seat frame (120), a seat reversing mechanism (130) and a stroller (1000). The seat reversing mechanism (130) is used for rotatably mounting the seat frame (120) to a lower frame (110). The seat reversing mechanism (130) comprises a push-handle frame (1400) and a seat locking member (1350), wherein the push-handle frame (1400) pivots between a first push-handle position and a second push-handle position; the seat locking member (1350) moves between a seat locking position and a seat unlocking position; when the seat locking member (1350) is located in the seat locking position, the seat locking member (1350) locks the relative rotation between the seat frame (120) and the lower frame (110); when the seat locking member (1350) is located in the seat unlocking position, the seat frame (120) can rotate relative to the lower frame (110); when the push-handle frame (1400) is located in the first push-handle position, the seat locking member (1350) is located in the seat locking position; when the push-handle frame (1400) is located in the second push-handle position, the seat locking member (1350) is located in the seat unlocking position; and when pivoting from the first push-handle position to the second push-handle position, the push-handle frame (1400) drives the seat locking member (1350) to move from the seat locking position to the seat unlocking position.

Description

Pivot joints, seat frame, seat reversing mechanism, and trolley Technical Field

[0001] This application relates to the field of mobile vehicles, and in particular to a pivot joint, a seat frame, a seat reversing mechanism, and a trolley. Background Technology

[0002] With the fast pace of modern life, consumer demand for strollers, such as baby strollers, is increasing, especially foldable strollers with reversible seats, which are widely popular due to their superior practicality and portability. However, the internal structure of the pivot joints of existing strollers that can achieve this function is usually quite complex, and the folding mode of the seat frame is limited. In addition, existing strollers that can achieve this function are relatively bulky when folded in forward-facing mode.

[0003] In addition, these strollers are complicated to operate when changing the seat position, making them inconvenient to use. Summary of the Invention

[0004] Therefore, it is necessary to provide a pivot joint, a seat frame, a seat reversing mechanism, and a trolley. The pivot joint has a simple structure, the seat frame has various folding modes, and the trolley has a small volume when folded in the forward-facing mode. The seat reversing mechanism can realize the forward and backward reversing function of the seat by pivoting the push handle, making it very convenient for consumers to use.

[0005] This application provides a seat reversing mechanism for rotatably mounting a seat frame to a subframe. The seat reversing mechanism includes a push arm and a seat locking member. The push arm pivots between a first push position and a second push position. The seat locking member moves between a seat locked position and a seat unlocked position. When the seat locking member is in the seat locked position, it locks relative rotation between the seat frame and the subframe; when the seat locking member is in the seat unlocked position, the seat frame is rotatable relative to the subframe. When the push arm is in the first push position, the seat locking member is in the seat locked position; when the push arm is in the second push position, the seat locking member is in the seat unlocked position; when the push arm pivots from the first push position to the second push position, it drives the seat locking member to move from the seat locked position to the seat unlocked position.

[0006] In some embodiments, the seat reversing mechanism further includes a connecting assembly, through which the pusher arm drives the seat locking member to move. The connecting assembly includes a slider. The slider slides between a first sliding position and a second sliding position. When the pusher arm is in the first pusher position, the slider is in the first sliding position; when the pusher arm is in the second pusher position, the slider is in the second sliding position. When the pusher arm pivots from the first pusher position to the second pusher position, it drives the slider to slide from the first sliding position to the second sliding position. When the slider slides from the first sliding position to the second sliding position, it drives the seat locking member to move from the seat locked position to the seat unlocked position.

[0007] In some embodiments, the pusher arm includes a seat drive portion that drives the slider to slide. The seat drive portion includes a first surface. The slider includes an abutment portion that is slidably connected to the first surface. When the pusher arm pivots from a first pusher position to a second pusher position, the extending direction of the first surface intersects with but is not perpendicular to the sliding direction of the slider. The seat drive portion drives the abutment portion to slide along the first surface.

[0008] In some embodiments, the pusher bracket rotates about an axial direction, and any direction perpendicular to the axial direction is radial, along which the slider slides. The contact point between the abutment portion and the first surface is the intersection of the sliding direction of the slider and the first surface.

[0009] In some embodiments, the abutment portion is cylindrical, and the first surface is tangent to the circumferential surface of the abutment portion.

[0010] In some embodiments, when the pusher frame is located in the first pusher position, the angle between the sliding direction of the slider and the extension direction of the first surface is greater than the angle between the sliding direction of the slider and the extension direction of the first surface when the pusher frame is located in the second pusher position.

[0011] In some embodiments, the seat drive unit further includes a second surface connected to the first surface. When the push arm is in the second push position, the second surface is perpendicular to the sliding direction of the slider, and the abutment portion abuts against the second surface.

[0012] In some embodiments, the pusher frame includes two push rods arranged opposite each other, the central axes of the two push rods defining the plane in which the pusher frame is located, and the centerline of the second surface is coplanar with the plane in which the pusher frame is located.

[0013] In some embodiments, the seat drive unit further includes a third surface connected to the second surface, the third surface and the first surface being symmetrically arranged with respect to the centerline of the second surface.

[0014] In some embodiments, the pusher frame rotates about an axis, with any direction perpendicular to the axis being radial, and the second surface is perpendicular to one of these radial directions. When the pusher frame is in the second pusher position, the sliding direction of the slider overlaps with the radial direction perpendicular to the second surface.

[0015] In some embodiments, the pusher frame rotates about an axis, and when the pusher frame pivots from the first pusher position to the second pusher position, the abutment portion moves in a direction away from the axis.

[0016] In some embodiments, the sliding direction of the slider is parallel to the moving direction of the seat locking member.

[0017] In some embodiments, the seat reversing mechanism further includes a connecting rod pivotally connected to the push arm. The connecting rod has a first pivot portion, and the push arm has a second pivot portion, the first and second pivot portions being pivotally connected about an axial direction. A sliding member is disposed at the first pivot portion and slides relative to the first pivot portion between a first sliding position and a second sliding position. The push arm has a seat drive portion, which is disposed at the second pivot portion and protrudes toward the first pivot portion to drive the sliding member to slide.

[0018] In some embodiments, the connecting assembly further includes a first connector passing through the connecting rod, one end of the first connector being connected to the slider, the seat lock being exposed on the connecting rod, and the other end of the first connector extending out of the connecting rod to be connected to the seat lock.

[0019] In some embodiments, the connecting rod is further provided with a steering member, and the first connecting member is transformed by the steering member to be parallel to the moving direction of the seat locking member, so as to connect with the seat locking member.

[0020] In some embodiments, the seat reversing mechanism further includes a push-hand lock. The first pivot and the second pivot together define a receiving space, and the push-hand lock is disposed in the receiving space and movable along the axial direction between a push-hand locked position and a push-hand unlocked position. The push-hand lock includes a locking portion that, when the push-hand lock is in the push-hand locked position, is simultaneously located at both the first and second pivots, preventing relative pivoting between the first and second pivots; when the push-hand lock is in the push-hand unlocked position, the locking portion is disengaged from the second pivot, allowing the second pivot to pivot relative to the first pivot.

[0021] In some embodiments, the pusher locking member is provided with a clearance hole through which the seat drive unit passes, and the seat drive unit can pivot within the clearance hole when it pivots with the pusher frame.

[0022] In some embodiments, the seat reversing mechanism further includes: a push-handle release member slidably disposed on the second pivot portion; and an operating member disposed on the push-handle frame and connected to the push-handle release member via a second connector. During operation, the operating member drives the push-handle release member to slide via the second connector, thereby driving the push-handle locking member from the push-handle locking position to the push-handle release position.

[0023] In some embodiments, the push-handle locking member further includes a release portion located on the side of the push-handle locking member facing the push-handle release member and protruding toward the push-handle locking member. The release portion has a first mating surface inclined relative to the axial direction. The push-handle release member has a second mating surface inclined relative to the axial direction. The first mating surface and the second mating surface engage with each other such that when the push-handle release member is moved under the operation of the operating member, it drives the push-handle locking member from the push-handle locking position to the push-handle releasing position.

[0024] In some embodiments, the seat reversing mechanism includes a connecting seat for rotatably connecting the seat frame to the underframe. The connecting seat includes a first seat for connecting to the underframe and a second seat for connecting to the seat frame, the second seat being rotatably connected to the first seat about an axis. The pusher frame includes two opposing push rods, the central axis of which defines a plane containing the pusher frame. When the pusher frame is in a first pusher position, there is an angle between the plane containing the pusher frame and the axis; when the pusher frame is in a second pusher position, the plane containing the pusher frame is coplanar with the axis, and the pusher frame is rotatable about the axis.

[0025] In some embodiments, the first seat body has a first locking hole, and the second seat body has a second locking hole that is opposite to and communicates with the first locking hole. The seat locking member is movably disposed within the second locking hole. When the seat locking member is in the seat locked position, a portion of the seat locking member extends into the first locking hole; when the seat locking member is in the seat unlocked position, the seat locking member retracts from the first locking hole. The direction of movement of the seat locking member is parallel to and spaced apart from the axis.

[0026] A first aspect of this application also provides a trolley, including a lower frame, a seat frame, and the aforementioned seat reversing mechanism. When the seat locking member is in the seat unlocked position, the seat frame can switch between a forward-facing mode and a rearward-facing mode relative to the lower frame.

[0027] In some embodiments, when the seat frame is in the forward mode or the rearward mode, the pusher frame can move from the second pusher position to the first pusher position.

[0028] A second aspect of this application provides a pivot joint comprising a first pivot seat, a second pivot seat, and a third pivot seat sequentially arranged along an axial direction, and a locking member movably disposed on the second pivot seat. The first, second, and third pivot seats pivot circumferentially about the axial direction. The locking member moves relative to the second pivot seat between a locked position and an unlocked position. When the locking member is in the locked position, the locking member disposed on the second pivot seat is simultaneously blocked in the circumferential direction by both the first and third pivot seats to lock the relative pivoting between the first, second, and third pivot seats, thereby locking the pivot joint. When the locking member is in the unlocked position, the first and third pivot seats simultaneously release their obstruction of the locking member in the circumferential direction to release the locking of the relative pivoting between the first, second, and third pivot seats, thereby unlocking the pivot joint.

[0029] In some embodiments, the locking member has a first locking portion on the side facing the first pivot seat, and the first pivot seat has a locking groove on the side facing the second pivot seat. The locking member has a second locking portion on the side facing the third pivot seat, and the third pivot seat has a locking groove and a second arc-shaped channel communicating with the locking groove on the side facing the second pivot seat. The locking groove and the locking groove both extend along the moving direction of the locking member, and the second arc-shaped channel extends along the circumferential direction. The moving direction of the locking member intersects with the circumferential direction. When the locking member is in the locked position, the first locking portion is located in the locking groove and is blocked by the groove wall of the locking groove in the circumferential direction, while the second locking portion is located in the locking groove and is blocked by the groove wall of the locking groove in the circumferential direction. When the locking member is in the unlocked position, the first locking portion disengages from the locking groove, and the second locking portion is located in the second arc-shaped channel.

[0030] In some embodiments, the third pivot seat has two locking grooves spaced apart circumferentially on the side facing the second pivot seat. When the locking member is in the locked position, the second locking part is located in one of the two locking grooves.

[0031] In some embodiments, the first pivot seat has two locking slots spaced apart circumferentially on the side facing the second pivot seat, and a first arcuate channel connecting the two locking slots. When the locking member is in the locked position, the first locking part is located in one of the two locking slots and the second locking part is located in one of the two locking slots, or the first locking part is located in the other of the two locking slots and the second locking part is located in the other of the two locking slots. When the locking member is in the unlocked position, the first locking part is located in the first arcuate channel.

[0032] In some embodiments, the locking member has a first locking portion on the side facing the first pivot seat, and the first pivot seat has a plurality of locking grooves spaced apart circumferentially and a first arc-shaped channel connecting the plurality of locking grooves on the side facing the second pivot seat. The locking member has a second locking portion on the side facing the third pivot seat, and the third pivot seat has a locking groove on the side facing the second pivot seat. Both the locking groove and the locking groove extend along the moving direction of the locking member, the first arc-shaped channel extends circumferentially, and the moving direction of the locking member intersects with the circumferential direction. The second pivot seat has a second abutment portion, and the third pivot seat has a third abutment portion opposite to the second abutment portion in the circumferential direction. When the second abutment portion and the third abutment portion abut against each other in the circumferential direction and the locking member is in the locked position, the first locking portion is located in one of the plurality of locking grooves and is blocked by the groove wall of the locking groove in the circumferential direction, while the second locking portion is located in the locking groove and is blocked by the groove wall of the locking groove in the circumferential direction. When the second abutting part and the third abutting part abut against each other in the circumferential direction and the locking member is in the unlocking position, the first locking part is located in the first arc-shaped channel, while the second locking part disengages from the locking groove and is opposite to the locking groove along the moving direction of the locking member.

[0033] In some embodiments, the pivot joint further includes a fourth pivot seat. The fourth pivot seat is disposed axially on the side of the third pivot seat away from the second pivot seat. The fourth pivot seat pivots circumferentially relative to the second and third pivot seats. The fourth pivot seat has a protrusion that passes through the third pivot seat and extends into the second pivot seat. When the locking member is in the locked position, the protrusion is held circumferentially by the second and third pivot seats to restrict the pivoting of the fourth pivot seat relative to the second and third pivot seats.

[0034] In some embodiments, when the locking member is in the unlocked position, the second pivot and the third pivot can pivot together relative to the first pivot, and the relative position between the second pivot and the third pivot remains unchanged during the pivoting process.

[0035] In some embodiments, when the locking member is in the unlocked position, the third pivot seat can pivot relative to the first pivot seat and the second pivot seat, and the relative position between the first pivot seat and the second pivot seat remains unchanged during the pivoting process.

[0036] In some embodiments, when the locking member is in the unlocked position, the second pivot seat and the third pivot seat can pivot relative to the first pivot seat, and the relative positions of the first pivot seat, the second pivot seat and the third pivot seat change during the pivoting process.

[0037] In some embodiments, the pivot joint further includes a fourth pivot seat. The fourth pivot seat is disposed axially on the side of the third pivot seat away from the second pivot seat. The fourth pivot seat pivots circumferentially relative to the first, second, and third pivot seats. When the locking member is in the locked position, it locks the relative pivoting between the first, second, third, and fourth pivot seats. When the locking member is in the unlocked position, it releases the locking of the relative pivoting between the second, third, and fourth pivot seats.

[0038] A second aspect of this application also provides a seat frame, the seat frame including a snap-fit ​​member, a seat body, and the aforementioned pivot joint. The snap-fit ​​member is connected to a first pivot seat for connection to a trolley frame. The seat body includes an upper frame connected to a second pivot seat and a lower frame connected to a third pivot seat, the seat body defining a seating space.

[0039] In some embodiments, the seat body includes an unfolded state and a first folded state. When the seat body is in the first folded state, the angle between the upper frame and the lower frame is smaller than the angle between the first frame and the second frame when the seat body is in the unfolded state. When the seat body is in the unfolded state and the locking member is in the locked position, the second locking part is located in one of the two locking slots. When the seat body is in the first folded state and the locking member is in the locked position, the second locking part is located in the other of the two locking slots. When the seat body is in the unfolded state or the first folded state and the locking member is in the locked position, the first locking part is located in the same locking slot.

[0040] In some embodiments, the seat body includes an unfolded state and a second folded state. When the seat body is in the second folded state, the angle between the first frame and the second frame is smaller than the angle between the first frame and the second frame when the seat body is in the unfolded state. When the seat body is in the unfolded state and the locking member is in the locked position, the first locking part is located in one of the two locking slots and the second locking part is located in one of the two locking slots. When the seat body is in the second folded state and the locking member is in the locked position, the first locking part is located in the other of the two locking slots and the second locking part is located in the other of the two locking slots.

[0041] In some embodiments, the seat body includes an unfolded state. When the seat body is in the unfolded state, the second abutment portion and the third abutment portion abut against each other in the circumferential direction. The seat body, while in the unfolded state, has multiple usage states by pivoting relative to the latching member. Each of the multiple usage states corresponds one-to-one with a plurality of locking slots. When the seat body is in one of the multiple usage states and the locking member is in the locked position, the first locking portion is located in a corresponding one of the multiple locking slots, and the second locking portion is located in the locking slot. When the seat body is in one of the multiple usage states and the locking member is in the unlocked position, the first locking portion is located in the first arcuate channel, and the second locking portion is opposite the locking slot along the movement direction of the locking member.

[0042] In some embodiments, the seat body further includes an armrest frame connected to the fourth pivot seat.

[0043] In some embodiments, the third pivot seat is provided with an arc-shaped through groove for the protrusion to move circumferentially, the arc-shaped through groove having a fifth limiting end and a sixth limiting end in the circumferential direction. The second pivot seat is provided with a third arc-shaped channel for the protrusion to move circumferentially, the third arc-shaped channel having a seventh limiting end and an eighth limiting end in the circumferential direction. The seat body includes an unfolded state and a folded state. When the seat body is in the folded state, the included angle between the first frame and the second frame is smaller than the included angle between the first frame and the second frame when the seat body is in the unfolded state. When the seat body is in the unfolded state and the locking member is in the locked position, the protrusion is clamped in the circumferential direction by the fifth limiting end and the seventh limiting end. When the seat body is in the folded state and the locking member is in the locked position, the protrusion is clamped in the circumferential direction by the sixth limiting end and the eighth limiting end.

[0044] A second aspect of this application also provides a trolley, including a frame and the aforementioned seat frame. The seat frame is mounted to the frame in a forward-facing configuration. The frame includes a push handle for a user to push the trolley. When the seat body is in the unfolded state, the upper frame and the push handle are located on the same side of the pivot joint, and the lower frame and the push handle are located on opposite sides of the pivot joint. When the seat body is in the first folded state, the upper frame, the lower frame, and the push handle are located on the same side of the pivot joint.

[0045] A second aspect of this application also provides a trolley, including a frame and the aforementioned seat frame. The seat frame is mounted to the frame in a rearward configuration. The frame includes a push handle for a user to push the trolley. When the seat body is in the unfolded state, the upper frame and the push handle are located on opposite sides of the pivot joint, and the lower frame and the push handle are located on the same side of the pivot joint. When the seat body is in the second folded state, the upper frame, the lower frame, and the push handle are located on the same side of the pivot joint.

[0046] A second aspect of this application also provides a vehicle frame, including a front stand, a rear stand, a connecting frame, a front wheel, and a rear wheel. The front stand includes an upper frame section and a lower frame section. The front stand is connected to the front wheel, and the rear stand is connected to the rear wheel. The size of the front wheel is smaller than the size of the rear wheel. The upper frame section is pivotally connected to the rear stand to form a first pivot point. One end of the connecting frame is pivotally connected to the rear stand to form a second pivot point. The other end of the connecting frame is pivotally connected to the lower frame section to form a third pivot point. The upper frame section and the lower frame section are pivotally connected to form a fourth pivot point. The upper frame section, the lower frame section, the connecting frame, and the rear stand form a four-bar linkage. Attached Figure Description

[0047] Figure 1 is a side view of the trolley when the pusher frame is in the first pusher position according to the first embodiment of this application;

[0048] Figure 2 is a side view of the trolley when the pusher frame is in the second pusher position according to the first embodiment of this application;

[0049] Figure 3 is a side view of a trolley with a seat frame positioned between a first seat position and a second seat position according to the first embodiment of this application;

[0050] Figure 4 is a perspective view of the seat frame of the trolley according to the first embodiment of this application;

[0051] Figure 5 is a perspective view of the trolley after the seat frame has been removed according to the first embodiment of this application;

[0052] Figure 6 is an exploded view of the trolley after removing the seat frame according to the first embodiment of this application;

[0053] Figure 7 is a perspective view of the second main body of the second seat of the trolley mounting base according to the first embodiment of this application;

[0054] Figure 8 is a perspective view of the first main body of the first seat of the trolley mounting base according to the first embodiment of the present application;

[0055] Figure 9 is a cross-sectional view of the trolley mounting base taken along line AA in Figure 1.

[0056] Figure 10 is an exploded view of a portion of the structure of the cart according to the first embodiment of this application;

[0057] Figure 11 is a perspective view of the internal structure of the second pivot joint of the pusher frame of the trolley according to the first embodiment of this application;

[0058] Figure 12 is a perspective view of the internal structure of the first pivot joint of the connecting rod of the trolley according to the first embodiment of this application;

[0059] Figure 13 is a front view of the internal structure of the second pivot joint of the trolley's handle frame according to the first embodiment of this application;

[0060] Figure 14 is a front view of the internal structure of the first pivot portion of the connecting rod of the trolley according to the first embodiment of this application;

[0061] Figure 15 is an exploded view of the first pivot portion of the connecting rod of the trolley according to the first embodiment of this application;

[0062] Figure 16 is a cross-sectional view of the first and second pivot joints of the trolley, taken along line AA in Figure 1.

[0063] Figure 17 is a schematic diagram of the cooperation relationship between the seat drive unit and the sliding member when the push handle of the trolley according to the first embodiment of this application is in the first push handle position;

[0064] Figure 18 is a schematic diagram of the cooperation relationship between the seat drive unit and the sliding member when the push handle of the trolley according to the first embodiment of this application is in the second push handle position;

[0065] Figure 19 is a schematic diagram of the cooperation relationship between the seat drive unit and the pusher release member when the pusher frame of the trolley according to the first embodiment of this application is in the first pusher position.

[0066] Figure 20 is a perspective view of the trolley frame provided according to the second embodiment of this application;

[0067] Figure 21A is a side view of the trolley provided according to the second embodiment of this application when the seat frame is installed in a forward-facing mode and the seat body is in an unfolded state;

[0068] Figure 21B is a side view of the trolley provided according to the second embodiment of this application when the seat frame is installed in a forward-facing mode and the seat body is in a folded state;

[0069] Figure 22A is a side view of the trolley provided according to the second embodiment of this application when the seat frame is installed in a rearward mode and the seat body is in an unfolded state;

[0070] Figure 22B is a side view of the trolley provided according to the second embodiment of this application when the seat frame is installed in a rearward mode and the seat body is in a folded state;

[0071] Figure 23 is a perspective view of the seat frame of the trolley provided according to the second embodiment of this application;

[0072] Figure 24 is a partial enlarged view of area A of the seat frame in Figure 23;

[0073] Figure 25 is an exploded view of a pivot joint provided according to the second embodiment of this application;

[0074] Figure 26 is an exploded view of the pivot joint provided according to the second embodiment of this application from another perspective;

[0075] Figure 27A is a partial enlarged view of area A of the seat frame in Figure 23 after the snap fastener is removed, where the locking element is in the locked position;

[0076] Figure 27B is a partial enlarged view of area A of the seat frame in Figure 23 after the snap fastener is removed, where the locking element is in the unlocked position;

[0077] Figure 28 is a partially enlarged side view of the seat frame according to the second embodiment of this application, in which the first pivot seat is partially removed but the reinforcing plate is retained when the frame is installed in the forward-facing mode;

[0078] Figure 29 is a partially enlarged side view of the seat frame according to the second embodiment of this application, in which the first pivot seat is partially removed but the reinforcing plate is retained when the frame is installed in the rearward mode;

[0079] Figure 30 is a structural schematic diagram of the snap-fit ​​component provided according to the second embodiment of this application;

[0080] Figure 31 is a structural schematic diagram of the locking member provided according to the second embodiment of this application;

[0081] Figure 32 is a schematic diagram of the structure of the third pivot seat provided according to some second embodiments of this application;

[0082] Figure 33 is a structural schematic diagram of the second pivot seat and locking member provided according to the second embodiment of this application;

[0083] Figure 34A is a partial side sectional view along the central axis of the backrest bar when the seat body provided according to the second embodiment of this application has the armrest frame hidden in the unfolded state and the locking member is in the locked position.

[0084] Figure 34B is a partial side sectional view along the central axis of the backrest bar when the seat body provided according to the second embodiment of this application has the armrest frame hidden in the unfolded state and the locking member is in the unlocked position.

[0085] Figure 34C is a partial side sectional view of the seat body provided according to the second embodiment of this application, with the armrest frame hidden in a semi-folded state, along the central axis of the backrest bar;

[0086] Figure 34D is a partial side sectional view along the central axis of the backrest bar when the seat body provided according to the second embodiment of this application has the armrest frame hidden in the folded state and the locking member is in the locked position.

[0087] Figure 35 is a structural schematic diagram of a fourth pivot seat provided according to some embodiments of this application;

[0088] Figure 36 is a perspective view of a vehicle frame provided according to some embodiments of this application in an unfolded state;

[0089] Figure 37 is a perspective view of the frame of Figure 36 with the seat frame removed in a semi-folded state;

[0090] Figure 38 is a side view of the trolley after it is fully folded according to some embodiments of this application. Detailed Implementation

[0091] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0092] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0093] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0094] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0095] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0096] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0097] Referring to Figures 1 to 3, which show side views of the stroller 1000 provided in the first embodiment of this application in different states, the stroller 1000 includes a lower frame 110, a seat frame 120, and a seat reversing mechanism 130. The seat frame 120 is rotatably mounted on the lower frame 110 via the seat reversing mechanism 130 and can rotate between a first seat position and a second seat position. When the seat frame 120 is in the first seat position, the occupant (e.g., a child or pet) sitting on the seat faces forward in the stroller's travel direction D1; this is defined as the forward-facing usage mode of the seat frame 120 (as shown in Figures 1 and 2). When the seat frame 120 is in the second seat position, the occupant (e.g., a child or pet) sitting on the seat faces backward in the stroller's travel direction D1; this is defined as the rearward-facing usage mode of the seat frame 120. That is, the seat frame 120 can be reversed. The seat frame 120 can be changed from the first seat position to the second seat position by rotating the seat frame 120 180° (as shown in Figure 3).

[0098] Referring to Figure 5, the lower frame 110 may include a front support 1110 and a rear support 1120, with the front support 1110 positioned in front of the rear support 1120 along the travel direction D1. The upper ends of the front support 1110 and the rear support 1120 are pivotally connected together. In the unfolded state, the front support 1110, the rear support 1120, and the support surface of the support trolley 1000 can form a generally triangular structure, thereby stably supporting the seat frame 120 and the seat reversing mechanism 130. Referring to Figures 5 and 6, in some embodiments, the front support 1110 may include two generally parallel and spaced-apart front legs 1111, and the rear support 1120 may include two generally parallel and spaced-apart rear legs 1121, with the upper ends of the two front legs 1111 and the upper ends of the two rear legs 1121 pivotally connected one-to-one.

[0099] Referring to Figure 5, two front wheels 1131 can be mounted on the bottom end of the front stand 1110, for example, the two front wheels 1131 can be respectively mounted on the bottom end of the two front legs 1111. Two rear wheels 1132 can be mounted on the bottom end of the rear stand 1120, for example, the two rear wheels 1132 can be respectively mounted on the bottom end of the two rear legs 1121. In some embodiments, the front wheels 1131 and the rear wheels 1132 can have different structures. For example, the diameter of the rear wheels 1132 can be larger than the diameter of the front wheels 1131, so that the user can better push the trolley 1000 from the side where the rear wheels 1132 are located to the side where the front wheels 1131 are located.

[0100] Referring to Figures 5 and 6, the seat reversing mechanism 130 may include a connector 1300 for rotatably connecting the seat frame 120 to the undercarriage frame 110. In some embodiments, the connector 1300 includes a first seat 1310 connected to the undercarriage frame 110 and a second seat 1320 connected to the seat frame 120, the second seat 1320 being rotatably connected to the first seat 1310, thereby allowing the seat frame 120 to be rotatably connected to the undercarriage frame 110.

[0101] Referring to Figures 5 and 6, in some embodiments, the first seat 1310 may be fixedly installed on the upper part of the lower frame 110, for example, fixedly installed on the upper part of the front support 1110. In some embodiments, the first seat 1310 may be fixedly installed between the two front support rods 1111. In some embodiments, the front support 1110 further includes a reinforcing rod 1112 (see Figure 9) fixedly connected between the two front support rods 1111, and the first seat 1310 may be fixedly installed on the reinforcing rod 1112. For example, the first seat 1310 may be sleeved on the reinforcing rod 1112 and fixedly connected to the reinforcing rod 1112 by fasteners such as screws.

[0102] Referring to Figures 7 to 10, in some embodiments, a pivot 1330 is provided in the connecting seat 1300, and the second seat 1320 is rotatably connected to the first seat 1310 via the pivot 1330. The second seat 1320 is rotatable relative to the pivot 1330 and the first seat 1310, and the pivot 1330 is relatively fixed to the first seat 1310. In some embodiments, the first seat 1310 may also rotate relative to the pivot 1330. In some embodiments, the first seat 1310 may be provided with a first rotating hole 1313, and the second seat 1320 may be provided with a second rotating hole 1323 opposite to and communicating with the first rotating hole 1313. The pivot 1330 can be simultaneously inserted into the first rotating hole 1313 and the second rotating hole 1323, so that the second seat 1320 can rotate relative to the first seat 1310. In some embodiments, a first limiting member 1331 and a second limiting member 1332 may be provided at opposite ends of the pivot 1330 to limit the relative movement of the first seat 1310 and the second seat 1320 in the direction of the axis of the pivot 1330. Specifically, the first seat 1310 and the second seat 1320 each have a first limiting surface 1314 and a second limiting surface 1324. The first end of the pivot 1330 protrudes from the first limiting surface 1314 of the first seat 1310, and a first limiting member 1331 is disposed at the first end of the pivot 1330 and abuts against the first limiting surface 1314 of the first seat 1310. The second end of the pivot 1330 protrudes from the first limiting surface 1324 of the second seat 1320, and a second limiting member 1332 is disposed at the second end of the pivot 1330 and abuts against the second end face 324 of the second seat 1330, thereby restricting the relative movement of the first seat 1310 and the second seat 1320 in the direction of the axis of the pivot 1330. The first limiting member 1331 and the second limiting member 1332 can be integrally formed with the pivot 1330 independently, or they can be components different from the pivot 1330. In the illustrated embodiment, the pivot 1330 is a bolt including a screw and a bolt head, the first limiting member 1331 is a nut threadedly connected to the end of the screw away from the bolt head, and the second limiting member 1332 is the bolt head. It should be understood that the implementation of the first limiting member 1331 and the second limiting member 1332 is not limited to this, as long as it can limit the relative movement of the first seat 1310 and the second seat 1320 in the direction of the axis of the pivot 1330. In some embodiments, a first bearing 1371, such as a tapered bearing, may also be provided in the first rotating hole 1313, and a second bearing may also be provided in the second rotating hole 1323 to facilitate the rotation of the pivot 1330.

[0103] In some embodiments, referring to Figures 8 and 9, the first seat 1310 includes an annular protrusion 1316 disposed around the axis of a pivot 1330, and the second seat 1320 includes an annular groove 1326 disposed around the axis of the pivot 1330. The annular protrusion 1316 is rotatably engaged in the annular groove 1326 about the axis of the pivot 1330 to ensure the stability of the second seat 1320 relative to the first seat 1310 about the axis of the pivot 1330. In some embodiments, a plurality of ball bearings 1340 are disposed between the annular protrusion 1316 and the annular groove 1326 to improve the smoothness of the rotation of the second seat 1320 relative to the first seat 1310. Specifically, the annular protrusion 1316 may be provided with a plurality of semi-circular recesses 1317, and the annular groove 1326 may be provided with annular slots 1327 with a semi-circular cross-section opposite to the plurality of semi-circular recesses 1317. A plurality of balls 1340 may be partially accommodated in the plurality of recesses 1317 and partially accommodated in the annular slots 1327, thereby improving the smoothness of rotation when the second seat 1320 rotates relative to the first seat 1310. The plurality of recesses 1317 and the plurality of balls 1340 may be evenly distributed around the axis of the pivot 1330. It should be understood that in other embodiments, the positions of the annular protrusion and the annular groove on the first seat 1310 and the second seat 1320 may be interchanged, and the positions of the plurality of recesses and the annular slots on the annular protrusion and the annular groove may also be interchanged.

[0104] The seat reversing mechanism 130 may further include a seat locking member 1350 disposed in the connecting seat 1300. The seat locking member 1350 is movable between a seat locked position and a seat unlocked position. When the seat locking member 1350 is in the seat locked position, the seat locking member 1350 locks the relative rotation between the seat frame 120 and the lower frame 110. When the seat locking member 1350 is in the seat unlocked position, the seat frame 120 is rotatable relative to the lower frame 110.

[0105] Referring to Figures 7 and 8, in some embodiments, the first seat 1310 is provided with a first locking hole 1315, which is spaced apart from the first rotating hole 1313 in a direction perpendicular to the axis of the pivot 1330. The second seat 1320 is provided with a second locking hole 1325, which is spaced apart from the second rotating hole 1323 in a direction perpendicular to the axis of the pivot 1330. The first locking hole 1315 and the second locking hole 1325 are arranged opposite to each other in a direction parallel to the axis of the pivot 1330 and communicate with each other. The seat locking member 1350 is disposed in the second locking hole 1325 and is movable relative to the second locking hole 1325 in a direction parallel to the axis of the pivot 1330. When the seat locking member 1350 is in the seat locked position, a portion of the seat locking member 1350 extends out of the second locking hole 1325 and enters into the first locking hole 1315, thereby restricting relative rotation between the first seat body 1310 and the second seat body 1320 about the pivot 330. When the seat locking member 1350 is in the seat unlocked position, the seat locking member 1350 disengages from the first locking hole 1315, thereby allowing relative rotation between the first seat body 1310 and the second seat body 1320.

[0106] Referring to FIG9, in some embodiments, the seat reversing mechanism 130 may further include a first elastic member 1360 disposed in a second locking hole 1325. The first elastic member 1360 biases the seat locking member 1350 toward the first locking hole 1315 such that, when no external force is applied, a portion of the seat locking member 1350 extends into and remains within the first locking hole 1315, thereby limiting the relative rotation between the first seat body 1310 and the second seat body 1320. In some embodiments, the first elastic member 1360 is a spring.

[0107] Referring to Figure 9, in some embodiments, there are two seat locking members 1350, which are symmetrically arranged about the axis of pivot 1330 (i.e., the axis of rotation of the second seat 1320). Correspondingly, there are also two first locking holes 1315, two second locking holes 1325, and two first elastic members 1360, all symmetrically arranged about the axis of rotation of the second seat 1320. It is understood that the number of seat locking members 1350, first locking holes 1315, second locking holes 1325, and first elastic members 1360 is not limited to this and can be set according to actual needs.

[0108] Referring to Figure 9, in some embodiments, the first seat 1310 includes a first body 1311 and a first cover 1312. A first locking hole 1315, an annular protrusion 1316, and a recess 1317 may be provided in the first body 1311. A first rotating hole 1313 is provided in the first body 1311 and the first cover 1312. The first cover 1312 may cover the end of the first body 1311 away from the second seat 1320. The surface of the first cover 1312 away from the second seat 1320 may be a first limiting surface 1314. Further, the first seat 1310 may also include a first outer cover 1301 for covering components such as the first limiting member 1331 and screws exposed on the outside of the first limiting surface 1314, to improve the aesthetics of the first seat 1310. Furthermore, a first reinforcing member 1381 may be provided at the end of the first main body 1311 facing the second base body 1320, as shown in Figure 8, to strengthen the strength of the first main body 1311.

[0109] Referring to Figure 9, in some embodiments, the second seat 1320 includes a second body 1321 and a second cover 1322. A second locking hole 1325, an annular groove 1326, and an annular slot 1327 may be disposed in the second body 1321. The second cover 1322 may cover the end of the second body 1321 away from the first seat 1310, and a second rotating hole 1323 is disposed on the second body 1321 and the second cover 1322. The surface of the second cover 1322 away from the first seat 1310 may be a second limiting surface 1324. Further, the second seat 1320 may also include a second outer cover 1302 for covering components such as the second limiting member 1332 and screws exposed on the outside of the second limiting surface 1324, thereby improving the aesthetics of the second seat 1320. In some embodiments, the second locking hole 1325 is a through hole disposed in the second body 1321, and the first elastic member 1360 located in the second locking hole 1325 may be disposed between the second cover 1322 and the seat locking member 1350. Further, a second reinforcing member 1382 may also be provided at the end of the second body 1321 facing the first seat 1310, as shown in FIG10, for strengthening the strength of the second body 1321.

[0110] Referring to Figures 1 to 3, the seat reversing mechanism 130 may further include a pusher bracket 1400, which is pivotable relative to the connecting seat 1300 between a first pusher position and a second pusher position, and drives the seat locking member 1350 from the seat locked position to the seat unlocked position when the pusher bracket 1400 pivots from the first pusher position to the second pusher position. In this way, the rotational locking between the seat frame 120 and the undercarriage frame 110 can be easily released. Referring to Figures 5 and 6, the pusher bracket 1400 may include two opposing pusher rods 1410 and a crossbar 1412 connecting the two pusher rods 1410, the central axes of the two pusher rods 1410 and the central axis of the crossbar 1412 defining the plane in which the pusher bracket 1400 is located. When the pusher 1400 is in the first pusher position (see Figure 1), the plane of the pusher 1400 can form an angle with the rotation axis of the second seat 1320. Specifically, the plane of the pusher 1400 can be tilted towards the rear wheel 1132 relative to the rotation axis of the second seat 1320. The consumer can stand behind the rear wheel 1132 to grasp and push the crossbar 1412 to push the trolley 1000. When the pusher 1400 is in the second pusher position (see Figure 2), the plane of the pusher 1400 can be coplanar with the rotation axis of the second seat 1320. The consumer can rotate the pusher 1400 in place (e.g., 180 degrees) around the rotation axis of the second seat 1320 to change the front and back orientation of the seat frame 20. After the seat frame 120 has changed its front and back orientation, the consumer can move the pusher 1400 back to the first pusher position so that the consumer can push the trolley 1000. Typically, the axis of rotation of the second seat 1320 (i.e., the axis of rotation of the seat frame 120) is perpendicular to the support surface (e.g., the ground) supporting the trolley 1000. Therefore, when in the first push position, the plane of the pusher frame 1400 can be tilted relative to the ground in the direction of the rear wheel 1132, and when in the second push position, the plane of the pusher frame 1400 can be perpendicular to the ground, i.e., the pusher frame 1400 can be in a vertical position. It should be understood that, in this document, the first push position and the second push position are positions relative to the undercarriage 110 (specifically the rear wheel 1132).

[0111] Referring to Figures 5 and 6, in some embodiments, the connecting seat 1300 is connected to the seat frame 120 and the push arm frame 1400 via a connecting rod 1500. Specifically, the connecting rod 1500 may be fixedly connected to the second seat body 1320, and opposite ends of the connecting rod 1500 may extend and protrude from opposite sides of the second seat body 1320 and connect to the seat frame 120 and the push arm frame 1400. The connecting rod 1500 may include a first connecting segment 1501 and a second connecting segment 1502. The first connecting segment 1501 may be fixedly connected to the second seat body 1320 and extend in a direction perpendicular to the rotation axis of the second seat body 1320. The two second connecting segments 1502 may extend from opposite ends of the first connecting segment 1501 toward the push arm frame 1400 in a direction parallel to the rotation axis of the second seat body 1320. The ends of the two second connecting segments 1502 away from the first connecting segment 1501 may form opposite ends of the connecting rod 1500. The two second connecting sections 1502 can be symmetrically arranged about the rotation axis of the second seat 1320.

[0112] Referring to Figures 9 and 10, in some embodiments, the second seat 1320 is provided with a through hole 1328, and the first connecting segment 1501 of the connecting rod 1500 passes through the through hole 1328 and is fixedly connected to the second seat 1320 by fasteners such as screws. The first connecting segment 1501 may be provided with a third rotating hole 1503, and the second end of the pivot 1330 protrudes from the second limiting surface 1324 after passing through the second rotating hole 1323 and the third rotating hole 1503. The first connecting segment 1501 may be located between the second body 1321 and the second cover 1322. Further, the first connecting segment 1501 may be located directly above the second locking hole 1325, and one end of the first elastic member 1360 may abut against the connecting rod 1500, and the other end may abut against the seat locking member 1350.

[0113] Referring to Figures 4 and 5, in some embodiments, the seat frame 120 is detachably fixed to opposite ends of the connecting rod 1500. For example, two second connecting segments 1502 may each be provided with a first engaging portion 1510, and opposite sides of the seat frame 120 may each be provided with a second engaging portion 1210. The second engaging portions 1210 detachably engage with the first engaging portions 1510, thereby detachably fixing the seat frame 120 to opposite ends of the connecting rod 1500.

[0114] Referring to Figures 5 and 6, in some embodiments, the pusher frame 1400 is pivotally connected to the opposite ends of the connecting rod 1500. For example, a first pivot portion 1520 may be provided at each of the opposite ends of the connecting rod 1500, and a second pivot portion 1420 may be provided at the ends of the two pusher rods 1410 away from the crossbar 1412. The two first pivot portions 1520 and the two second pivot portions 1420 are pivotally connected about the same axis in a one-to-one correspondence, thereby making the pusher frame 1400 pivotally connected to the connecting rod 1500. The direction of the rotation axis of the first pivot portion 1520 and the second pivot portion 1420 is defined as the axial direction, and any direction perpendicular to the axial direction is defined as the radial direction. In some embodiments, regardless of whether the pusher frame 1400 is in the first pusher position or the second pusher position, the plane on which the pusher frame 1400 is located is coplanar with one of the radial directions. The radial direction coplanar with the plane on which the pusher frame 1400 is located is defined as the first radial direction, which pivots with the pivoting of the pusher frame 1400. Since the plane on which the pusher frame 1400 is located is also coplanar with the rotation axis of the second seat 1520 in the second pusher position, it can be seen that the rotation axis of the second seat 1520 is still parallel to the first radial direction at this time. When the pusher frame 1400 is in the second pusher position, the structure of the pusher frame 1400 and the connecting rod 1500 can be symmetrical about the rotation axis of the seat frame 120 and can rotate around the rotation axis of the seat frame 120. The following description takes the pivoting structure of the pusher frame 1400 and the connecting rod 1500 on one side of the trolley 1000 as an example.

[0115] Referring to Figures 11 to 14, in some embodiments, a first pivot hole 1502 is provided in the first pivot portion 1520, and a second pivot hole 1402 is provided opposite to and communicating with the first pivot hole 1502. A pivot shaft 1430 extending axially (see Figure 16) can pass through the first pivot hole 1502 and the second pivot hole 1402 so that the first pivot portion 1520 and the second pivot portion 1420 are pivotally connected.

[0116] In some embodiments, the first pivot portion 1520 and the second pivot portion 1420 together define a receiving space. The first pivot portion 1520 is provided with a cylindrical protrusion 1521 located within the receiving space and protruding toward the second pivot portion 1420. The second pivot portion 1420 is provided with a protrusion 1421 located within the receiving space and protruding toward the first pivot portion 1520, the protrusion 1421 having a receiving hole 1403, the cylindrical protrusion 1521 being inserted into the receiving hole 1403. Furthermore, the first pivot hole 1502 can be disposed in the cylindrical protrusion 1521, and the second pivot hole 1402 can be disposed in the bottom wall of the receiving hole 1403. Thus, when the pivot shaft 1430 passes through the first pivot hole 1502 and the second pivot hole 1402, the cylindrical protrusion 1521 and the protrusion 1421 can surround the pivot shaft 1430, which makes the pivoting of the pusher frame 1400 relative to the connecting rod 1500 more stable.

[0117] Referring to Figure 15, in some embodiments, the seat reversing mechanism 130 may further include a connecting assembly 1530, which is disposed within the first pivot portion 1520 and the connecting rod 1500. The protrusion 1421 is driven to connect with the seat locking member 1350 within the connecting seat 1300 via the connecting assembly 1530. When the push arm 1400 pivots relative to the connecting rod 1500, the protrusion 1421 rotates with the push arm 1400 and drives the seat locking member 1350 to move between a seat locked position and a seat unlocked position via the connecting assembly 1530. This protrusion 1421 may also be referred to as the seat drive portion 1421; herein, the protrusion 1421 and the seat drive portion 1421 are used interchangeably.

[0118] In some embodiments, referring to FIG15, the connecting assembly 1530 may include a slider 1531 and a first connector 1532 (e.g., a steel wire). The slider 1531 is disposed within a receiving space and is slidable relative to a first pivot 1520. The first connector 1532 may be disposed within a cavity of the connecting rod 1530. One end of the first connector 1532 is connected to the slider 1531 (e.g., a fixed connection), and the other end is connected to the seat lock 1350 (e.g., a fixed connection). When the pusher arm 1400 pivots relative to the connecting rod 1500, the protrusion 1421 rotates with the pusher arm 1400 and drives the slider 1531 to slide, thereby moving the seat lock 1350 between a seat locked position and a seat unlocked position via the first connector 1532. The first connecting member 1532 can extend within the cavity of the connecting rod 1500 along the extension direction of the connecting rod 1500. Therefore, the first connecting member 1532 extends within the first connecting section 1501 in a direction perpendicular to the rotation axis of the second seat 1320. At this time, a steering member 1550 (e.g., a roller) can be provided within the first connecting section 1501 at a position above the second locking hole 1325 (see Figure 9). The steering member 1550 causes the first connecting member 1532 to change from an extension direction perpendicular to the rotation axis of the second seat 1320 to an extension direction parallel to the rotation axis of the second seat 1320, that is, to change to be consistent with the moving direction of the seat locking member 1350, so as to connect with the seat locking member 1350 and facilitate driving the seat locking member 1350 from the seat locking position to the seat unlocking position. Furthermore, a through hole 1505 (see Figure 9) extending along the rotation axis parallel to the second seat body 1320 may be provided on the first connecting section 1501, and the first connector 1532 may pass through the through hole 1505 to connect with the seat locking member 1350.

[0119] Referring to Figures 12 and 14, the sliding direction of the slider 1531 can be parallel to one of the radial directions. A first sliding groove 1506 can be provided in the first pivot portion 1520. The slider 1531 can be disposed in the first sliding groove 1506 and can slide between a first sliding position and a second sliding position within the first sliding groove 1506. When the slider 1531 slides from the first sliding position to the second sliding position, the seat locking member 1350 moves from the seat locking position to the seat unlocking position. A first clearance hole 15313 (refer to Figure 15) can also be provided in the middle of the slider 1531, through which the cylindrical protrusion 1521 can be inserted into the receiving hole 1403. The first clearance hole 15313 can prevent the cylindrical protrusion 1521 from affecting the sliding of the slider 1531. When the slider 1531 abuts against the cylindrical protrusion 1521 in its sliding direction, the slider 1531 is in the first sliding position. In the illustrated embodiment, the slider 1531 slides along a radial direction, and the direction of sliding of the slider 1531 is defined as the second radial direction. When the pusher 1400 is in the first pusher position, there is an angle between the first radial direction and the second radial direction.

[0120] Referring to Figures 15, 17, and 18, in some embodiments, the slider 1531 includes a main body portion 15311 slidably disposed in a first groove 1506 and an abutment portion 15312 protruding from the main body portion 15311 toward a second pivot portion 1420. The abutment portion 15312 contacts the side of the protrusion 1421 (also referred to as the seat drive portion 1421). When the push arm 400 pivots relative to the connecting rod 1500 from a first push arm position to a second push arm position, the protrusion 1421 pivots with the push arm 400, and the side of the protrusion 1421 applies a thrust to the abutment portion 15312, thereby driving the slider 1531 to slide. In the illustrated embodiment, the abutment portion 15312 is cylindrical.

[0121] Referring to Figures 17, 18, and 19, in some embodiments, the side of the protrusion 1421 includes a first surface 14211. During the pivoting of the protrusion 1421 with the pusher frame 1400 between the first pusher position and the second pusher position, the extending direction of the first surface 14211 always intersects with but is not perpendicular to the sliding direction of the slider 1531. Although the extending direction of the first surface 14211 always intersects with but is not perpendicular to the sliding direction of the slider 1531 during the pivoting of the pusher frame 1400 between the first pusher position and the second pusher position, the angle between the extending direction of the first surface 14211 and the sliding direction of the slider 1531 changes. This allows the pivoting of the first surface 14211 to drive the slider 1531 (specifically, the abutment portion 15312) to slide along the first surface 14211 while also driving the slider 1531 to slide along its sliding direction. In the embodiment shown in Figure 17, the extending direction of the first surface 14211 always intersects the second radial direction but is not perpendicular to it during the pivoting process of the push frame 1400 about the axial direction. The abutment portion 15312 is exactly opposite to the axial direction along the second radial direction, that is, the abutment portion 15312 is located on the second radial direction. Therefore, the contact point between the abutment portion 15312 and the first surface 14211 is the intersection point of the second radial direction and the first surface 14211. As the angle between the extending direction of the first surface 14211 and the second radial direction changes during the pivoting process of the first surface 14211, the intersection point between the first surface 14211 and the second radial direction also changes, which can push the abutment portion 15312 to slide along the second radial direction. At the same time, since the abutment portion 15312 is cylindrical, the first surface 14211 will be tangent to different positions on the circumferential surface of the abutment portion 15312, so as to better push the abutment portion 15312 to slide along the second radial direction. In the embodiment shown in FIG17, the extension direction of the first surface 14211 also intersects with the first radial direction but is not perpendicular to it.

[0122] When the pusher bracket 400 pivots relative to the connecting rod 1500 from the first pusher position to the second pusher position, it drives the slider 1531 to slide relative to the axial direction along its sliding direction (in the embodiment shown, the abutment portion 15312 slides away from the axial direction), and the angle between the sliding direction of the slider 1531 and the first surface 14211 becomes smaller and smaller. Referring to Figures 17, 18 and 19, in the illustrated embodiment, the abutment portion 15312 slides from the lower part of the first surface 14211 to the upper part of the first surface 14211. During this period, the protrusion 1421 applies an upward thrust to the abutment portion 15312, causing the slider 1531 to slide from the first sliding position to the second sliding position.

[0123] Referring to Figures 17, 18, and 19, the side of the protrusion 1421 further includes a second surface 14212 that contacts the first surface 14211. When the pusher arm 1400 pivots to the second pusher position, the abutment portion 15312 slides from the first surface 14212 onto the second surface 14212 and abuts against it. The extending direction of the second surface 14212 is perpendicular to the sliding direction of the slider, thus restricting the abutment portion 15312 from sliding from the second sliding position to the first sliding position along its sliding direction. At this time, without the action of external force, the second surface 14212 can support the abutment portion 15312, thereby keeping the slider 1531 in the second sliding position and keeping the seat locking member 1350 in the seat unlocked position. The first surface 14211 and the second surface 14212 can smoothly transition to ensure that the abutment portion 15312 slides smoothly on the side of the protrusion 1421. In the embodiments shown in Figures 17 and 18, the extending direction of the second surface 14212 is also perpendicular to the first radial direction. When the pusher frame 1400 pivots to the second pusher position, the first radial direction coincides with the second radial direction, indicating that the second radial direction is also parallel to the rotation axis of the second seat 1520. Furthermore, in the illustrated embodiment, the centerline of the second surface 14212 also coincides with the first radial direction.

[0124] Referring to Figures 17, 18, and 19, the side of the protrusion 1421 further includes a third surface 14213 that contacts the second surface 14212. The third surface 14213 and the first surface 14211 are arranged in a mirror image symmetrical about the center line of the second surface 14212. Thus, when the user rotates the push arm 1200 to change the front-back orientation of the seat frame 120, and then pivots the push arm 1400 from the second push arm position to the first push arm position, the abutment portion 15312 can maintain contact with the third surface 14213 and slide on the third surface 14213. It can be seen that the process of pivoting the push arm 1400 from the second push arm position to the first push arm position is similar to the process of pivoting the push arm 1400 from the first push arm position to the second push arm position, but in the opposite direction. The abutment portion 15312 moves closer to the axial direction along the sliding direction of the slider, and the angle between the sliding direction of the slider 1531 and the extending direction of the third surface 14213 increases. Specifically, in the embodiments shown in Figures 17 and 18, the abutment portion 15312 slides from the upper part to the lower part of the third surface 14213. In the embodiments shown in Figures 17 and 18, since the centerline of the second surface 14212 coincides with the first radial direction, the first surface 14211 and the third surface 14213 are also mirror-symmetrical about the first radial direction.

[0125] Referring to Figure 15, in some embodiments, a push-handle locking member 1450 is further provided between the first pivot portion 1520 and the second pivot portion 1420 for locking the relative pivoting of the first pivot portion 1520 and the second pivot portion 1420. Referring in conjunction with Figures 11 to 14 and Figure 19, in some embodiments, a first locking groove 1508 communicating with the receiving space is provided on the inner peripheral wall of the first pivot portion 1520, and a second locking groove 1408 communicating with the receiving space is provided on the inner peripheral wall of the second pivot portion 1420. When the push-handle locking member 1450 locks the relative pivoting of the first pivot portion 1520 and the second pivot portion 1420, the first locking groove 1508 and the second locking groove 1408 have openings facing each other in a direction parallel to the pivot axis (i.e., axial direction) of the push-handle frame 1400, thereby allowing the first locking groove 1508 and the second locking groove 1408 to communicate with each other in a direction parallel to the pivot axis of the push-handle frame 1400. The push handle locking member 1450 includes an annular portion 1451 extending about a pivot axis of the push handle frame 1400 and a locking portion 1452 projecting from the side of the annular portion 1451. The annular portion 1451 is received within a receiving space. When the push handle locking member 1450 is in the push handle locked position, a portion of the locking portion 1452 is located in a first locking groove 1508 and another portion is located in a second locking groove 1408 to restrict pivoting of the second pivot portion 1420 relative to the first pivot portion 1520. When the push handle locking member 1450 is in the push handle unlocked position, the locking portion 1452 is fully located in the first locking groove 1508 (i.e., disengaged from the second locking groove 1408), thereby allowing the second pivot portion 1420 to pivot relative to the first pivot portion 1520. Furthermore, a second elastic member 1480 may be provided between the push handle locking member 1450 and the first pivot portion 1510. The second elastic member 1480 biases the push handle locking member 1450 toward the push handle locking position, that is, biases the push handle locking member 1450 toward the second pivot portion 1420, so that the push handle locking member 1450 is held in the push handle locking position without external force. There may be multiple locking parts 1452, and correspondingly, there may be multiple first locking grooves 1508 and second locking grooves 1408. The multiple locking parts 1452, multiple first locking grooves 1508, and multiple second locking grooves 1408 may be evenly distributed around the pivot axis of the push handle frame 400.

[0126] Referring to Figures 11 and 13, in some embodiments, a push-handle release member 1440, which is driven and connected to the push-handle locking member 1450, is further provided between the first pivot portion 1520 and the second pivot portion 1420. An operating member 1460 (see Figure 6 or 7, specifically mounted on the crossbar 1412) may be provided on the push-handle frame 1400. The operating member 1460 can be connected to the push-handle release member 1440 via a second connecting member 1470 (e.g., a steel wire). During operation, the operating member 1460 can move the push-handle release member 1440 via the second connecting member 1470, thereby driving the push-handle locking member 1450 from the push-handle locked position to the push-handle released position.

[0127] In some embodiments, the push-to-release member 1440 is slidably disposed within the second pivot portion 1420. Specifically, the second pivot portion 1420 may be provided with a second groove 1406 extending parallel to the first radial direction. The push-to-release member 1440 may be disposed within the second groove 1406 and may slide along the second groove 1406. The top and bottom walls of the second groove 1406 may respectively define a third sliding position and a fourth sliding position of the push-to-release member 1440. When the push-to-release member 1440 slides from the third sliding position to the fourth sliding position, the push-to-lock member 1450 moves from the push-to-lock position to the push-to-release position. The push-to-release member 1440 may also be provided with a second clearance hole 14401 through which a protrusion 1421 can pass, and the protrusion 1421 may protrude toward the first pivot portion 1520 through the second clearance hole 14401. The second clearance hole 14401 prevents the protrusion 1421 from affecting the sliding of the push-to-release member 1440. Furthermore, a third elastic member 1490 (see Figure 11) can be provided between the protrusion 1421 and the push-to-release member 1440. The third elastic member 1490 biases the push-to-release member 1440 toward the third sliding position of the push-to-release member 1440, so that the push-to-release member 1440 is held in the third sliding position without external force.

[0128] Referring to Figures 13, 15, and 16, in some embodiments, the push-to-lock member 1450 further includes a release portion 1453 projecting from the inner edge of the annular portion 1451 toward the second pivot portion 1420, and the push-to-lock release member 1440 can be driven connected to the release portion 1453. For example, the release portion 1453 may have a first mating surface 14532 inclined relative to the pivot axis of the second pivot portion 1420, and the push-to-lock release member 1440 may have a second mating surface 14402 inclined relative to the pivot axis of the second pivot portion 1420. The push-to-lock release member 1440 can be driven connected to the release portion 1453 through contact engagement between the second mating surface 14402 and the first mating surface 14532. For example, the release portion 1453 may taper from the annular portion 1453 toward the pivot axis of the second pivot portion 1420, thereby defining an outer conical surface, which can serve as the first mating surface 14532. The push-to-release member 1440 may define an inner conical surface that matches the outer conical surface, which may serve as a second mating surface 14402. When the push-to-release member 1440 slides from the third sliding position to the fourth sliding position, the push-to-release member 1440 drives the push-to-lock member 1450 to move from the push-to-lock position to the push-to-release position via the release part 1453.

[0129] Referring to Figures 15 and 19, in some embodiments, the pusher locking member 1450 is provided with a third clearance hole 14501 extending axially through the pusher locking member 1450. The protrusion 1421 can protrude toward the first pivot portion 1520 by passing sequentially through the second clearance hole 14401 and the third clearance hole 14501. The shape of the third clearance hole 14501 does not prevent the protrusion 1421 from pivoting with the pusher frame 1400 between the first pusher position and the second pusher position. Specifically, the side of the protrusion 1421 may include a first arcuate surface 14214 disposed opposite to the second surface 14212. The inner wall of the third clearance hole 14501 opposite to the first arcuate surface 14214 of the protrusion 1421 may be formed with a second arcuate surface 14502. The radius of curvature of the second arcuate surface 14502 can be greater than the radius of curvature of the first arcuate surface 14214, so as to allow the protrusion 1421 to pivot within a certain range above the second arcuate surface 14502. Furthermore, the inner wall of the third clearance hole 14501 may also form a limiting portion to restrict the protrusion 1421 from pivoting away from the first pusher position beyond the second pusher position, that is, to hold the protrusion 1421 in the second pusher position. Specifically, the inner wall of the third clearance hole 14501 is formed with two limiting inclined surfaces 14503, respectively located on both sides of the second arcuate surface 14502 and symmetrical about the second arcuate surface 14502. When the pusher frame 1400 is in the first pusher position, one of the limiting inclined surfaces 14503 abuts against the first surface 14211 or the third surface 14213 of the protrusion 1421, thereby restricting the protrusion 1421 from pivoting away from the first pusher position beyond the second pusher position. That is, the two limiting inclined surfaces 14503 form the limiting part.

[0130] The following example illustrates the seat reversing process of the stroller 1000, with the push handle 1400 in the first push handle position and the seat frame 120 in the forward direction of the stroller 1000. The consumer first presses the operating component 1460, which, through the second connecting component 1470, pulls the push handle release component 1440 upwards to the fourth sliding position, and drives the push handle locking component 1450 from the push handle locking position to the push handle release position. At this point, the consumer can push the push handle 1400 from the first push handle position to the second push handle position. The seat drive unit 1421 pivots with the push handle 1410, forcing the abutment portion 15312 of the slider 1531 to slide along the first surface 14211 of the seat drive unit 1421 and move upward along the sliding direction of the slider 1531. This, in turn, drives the seat locking member 1350 to move upward along a direction parallel to the rotation axis of the seat frame 120 via the first connector 1532. Simultaneously, the second locking groove 1408 pivots with the push handle 1410 and is offset from the locking portion 1452 of the push handle locking member 1450. The consumer can then release the operating member 1460, allowing the push handle release member 1440 to reset to the third sliding position via the third elastic member 1490. Only when the abutment portion 15312 of the slider 1531 moves above the second surface 14212 does the seat locking member 1350 completely disengage from the first locking hole 1315. Then, by rotating the pusher frame 1400 by 180 degrees in place around the rotation axis of the seat frame 120, the pusher frame 1400 can drive the second seat body 1320, the connecting rod 1500 and the seat frame 120 to rotate, thereby causing the seat frame 120 to rotate from the forward mode to the rearward mode. After the seat frame 120 has been rotated forward and backward, the consumer can push the push arm 1400 from the second push arm position to the first push arm position, so that the abutting part 15312 of the sliding member 1531 moves from above the second surface 14212 to the third surface 14213, and slides along the third surface 14213 of the seat drive part 1421 away from the second surface 14212, until the second locking groove 1408 on the second pivot part 1420 is opposite to the locking part 1452 of the push arm locking member 1450. At this time, the push arm locking member 1450 is reset to the push arm locking position under the action of the second elastic member 1480. At the same time, the sliding member 1531 abuts downward along its sliding direction to the cylindrical protrusion 1521 and resets to the first sliding position. The seat locking member 1350 is reset to the seat locking position under the action of the first elastic member 1360, and the first surface 14211 abuts against the limiting inclined surface 14503 opposite to it.

[0131] The trolley provided in the first embodiment of this application can realize the forward and backward reversal function of the seat by pivoting the push handle, making it very convenient for consumers to use.

[0132] Referring to Figures 20, 23, and 36, a second embodiment of this application provides a trolley, which includes a frame 2000 and a seat frame 220 mounted to the frame 2000. The frame 2000 includes a lower frame 210, an upper frame 230, and a mounting base 2300. The upper frame 230 and the lower frame 210 are connected together via the mounting base 2300. The seat frame 220 is detachably mounted to the upper frame 230. Specifically, the upper frame 230 may be provided with a card holder 2540, and the seat frame 220 may be provided with a snap-fit ​​element 2210. The seat frame 220 can be detachably mounted to the upper frame 230 by snapping the snap-fit ​​element 2210 into the card holder 2540. In the embodiment shown in Figure 20, the upper frame 230 is provided with two spaced-apart card holders 2540, and the seat frame 220 includes two snap-fit ​​members 2210 located on both sides of the seat frame 220. The two card holders 2540 can be connected to the two snap-fit ​​members 2210 respectively. As shown in Figure 21A, the seat frame 220 can be installed forward-facing onto the upper frame 230, so that the passenger sitting on the seat faces away from the consumer standing behind the trolley. As shown in Figure 22A, the seat frame 220 can also be installed rearward-facing onto the upper frame 230, so that the passenger sitting on the seat faces the consumer standing behind the trolley. That is, the seat frame 220 can be installed on the upper frame 230 in two modes. The mode in which the seat frame 220 is installed in the front of the upper frame 230 is defined as the forward mode, and the mode in which the seat frame 220 is installed in the rear of the upper frame 230 is defined as the rear mode. Simply remove the seat frame 220 from the upper frame 230 and rotate it 180° so that the positions of the two clips 2210 are interchanged. Then insert the two clips 2210 into the two clip seats 2540 respectively to realize the conversion between the forward mode and the rear mode of the seat frame 220. It should be understood that the conversion method of the seat frame 220 between the forward and backward modes is not limited to this. For example, the conversion method of the first embodiment can also be adopted, that is, the mounting base 2300 can be the same as the connecting base 1300 of the first embodiment, and the pusher frame 2400 can be the pusher frame 1400 of the first embodiment. The conversion of the seat frame 220 between the forward and backward modes can be achieved by pivoting the pusher frame between the first pusher position and the second pusher position. For details, please refer to the first embodiment, which will not be repeated here.

[0133] Referring to Figure 20, the underframe 210 may include a front stand 2110, a rear stand 2120, a front wheel 2131, and a rear wheel 2132. The upper ends of the front stand 2110 and the rear stand 2120 are pivotally connected together. The front wheel 2131 is connected to the lower end of the front stand 2110, and the rear wheel 2132 is connected to the lower end of the rear stand 2110. The diameter of the front wheel 2131 is smaller than the diameter of the rear wheel 2132.

[0134] Referring to Figures 20 and 36, the upper frame 230 may include a push handle 2400 and a connecting rod 2500. The connecting rod 2500 can be mounted on the mounting base 2300 and protrudes from both sides of the mounting base 2300 to form two opposing connecting ends. The two ends of the push handle 2400 can be pivotally connected to the corresponding outer sides of the two connecting ends of the connecting rod 2500. The two pivot points of the two ends of the push handle 2400 and the connecting rod 2500 are both located between the front wheel 2131 and the rear wheel 2132. The push handle 2400 and the rear wheel 2132 are located on the same side of the pivot points of the push handle 2400 and the connecting rod 2500, specifically tilted upwards from front to back to facilitate the user pushing the cart. Two card holders 2540 are correspondingly arranged on the inner sides of the two connecting ends of the connecting rod 2500 so that the seat frame 220 can be mounted on the inner side of the connecting rod 2500. It should be understood that the specific structure of the upper frame 230 and its connection method with the lower frame 210 are not limited thereto, as long as they can satisfy the requirements for forward and rearward installation of the seat frame 220 on the upper frame 210. It should be understood that in this document, "upper" and "lower" are relative to the support surface supporting the trolley (e.g., the ground). For example, "upper frame" refers to the frame portion away from the support surface of the trolley, while "lower frame" refers to the frame portion close to the support surface of the trolley. "Forward" and "rearward" are relative to the direction of travel of the trolley. For example, "forward" refers to the direction of travel of the trolley, and "rearward" refers to the direction opposite to the direction of travel of the trolley.

[0135] Referring to Figures 20, 21A, 21B, 22A, 22B, and 24, the seat frame 220 may include a seat body for defining a seating space, the seat body including an upper frame 2220, a lower frame 2230, and an armrest frame 2600. The upper frame 2220, lower frame 2230, and armrest frame 2600 may each have a generally U-shaped structure. The upper frame 2220 may include two generally parallel and opposing first rods 2221 and a top rod 2222 connecting the two first rods 2221. The lower frame 2230 may include two generally parallel and opposing second rods 2231 and a bottom rod 2232 connecting the two second rods 2231. The two ends of the upper frame 2220 (the ends of the two first rods 2221 away from the top rod 2222) may be pivotally connected to two snap-fit ​​members 2210. The two ends of the upper frame 2220 (the ends of the two first rods 2221 away from the top rod 2222) can also be pivotally connected to the two ends of the lower frame 2230 (the ends of the two second rods 2231 away from the bottom rod 2232). The two ends of the lower frame 2230 can also be pivotally connected to the two ends of the armrest frame 2600. Through the relative pivoting between the upper frame 2220 and the lower frame 2230, the seat body can switch between an unfolded state and a folded state. When the seat body is in the unfolded state (as shown in Figures 21A and 22A), the upper frame 2220 and the lower frame 2230 can be basically located on the same plane, that is, the plane enclosed by the upper frame 2220 and the plane enclosed by the lower frame 2230 are coplanar, the included angle between the upper frame 2220 and the lower frame 2230 is approximately 180°, and the armrest frame 2600 is located between the upper frame 2220 and the lower frame 2230. When the seat body is in the folded state (as shown in Figures 21B and 22B), the angle between the upper frame 2220 and the lower frame 2230 is smaller than the angle between the upper frame 2220 and the lower frame 2230 when the seat body is in the unfolded state, and the upper frame 2220 and the lower frame 2230 can be substantially parallel to each other, with the angle between the upper frame 2220 and the lower frame 2230 being approximately 0°. The armrest frame 2600 partially overlaps with one of the upper frame 2220 and the lower frame 2230. Therefore, the seat body can be folded substantially 180 degrees. It should be understood that in other embodiments, the angle between the upper frame 2220 and the lower frame 2230 when the seat body is in the unfolded state is greater than the angle between the upper frame 2220 and the lower frame 2230 when the seat body is in the folded state.

[0136] Referring to Figures 21A, 21B, 22A and 22B, in the illustrated embodiment, the upper frame 2220 is used to support the back of the occupant, and the lower frame 2230 is used to support the lower legs of the occupant.

[0137] Referring to Figure 21A, when the seat frame 220 is installed on the upper frame 230 in a forward-facing mode and the seat body is in the unfolded state, the upper frame 2220 is located above the lower frame 2230. The upper frame 2220 and the rear wheel 2132 are located on the same side of the pivot position of the upper frame 2220 and the lower frame 2230. The lower frame 2230 and the front wheel 2131 are located on the same side of the pivot position of the upper frame 2220 and the lower frame 2230. The upper frame 2220, the lower frame 2230 and the pusher frame 2400 are all tilted upward from front to back, and the upper frame 2220 is set closer to the pusher frame 2400 than the lower frame 2230.

[0138] Referring to Figure 21B, when the seat frame 220 is installed on the upper frame 230 in a forward-facing mode and the seat body is in a folded state, this folded state is defined as the first folded state. Compared with the unfolded state shown in Figure 21A, the position of the upper frame 2220 remains unchanged, and the lower frame 2230 moves toward the upper frame 2220 to be above the upper frame 2220 so as to be approximately parallel to the upper frame 2220, so that the upper frame 2220, the lower frame 2220 and the pusher arm 2400 are all located on the same side of the pivot position of the upper frame 2220 and the lower frame 2230.

[0139] Referring to Figure 22A, when the seat frame 220 is installed on the upper frame 230 in a rearward configuration and the seat body is in the unfolded state, the upper frame 2220 is located above the lower frame 2230. The upper frame 2220 and the front wheel 2131 are located on the same side of the pivot position of the upper frame 2220 and the lower frame 2230. The lower frame 2230 and the rear wheel 2132 are located on the same side of the pivot position of the upper frame 2220 and the lower frame 2230. Both the upper frame 2220 and the lower frame 2230 are inclined downward from front to back, while the push handle 2400 is inclined upward from front to back and is located between the upper frame 2220 and the lower frame 2230.

[0140] Referring to Figure 22B, when the seat frame 220 is installed on the upper frame 230 in a rearward mode and the seat body is in a folded state, this folded state is defined as the second folded state. Compared with the unfolded state shown in Figure 22A, the upper frame 2220 and the lower frame 2230 are pivoted towards each other and are set roughly parallel to each other. The upper frame 2220 is still located above the lower frame 2230, and the upper frame 2220, the lower frame 2220 and the push handle 2400 are all located on the same side of the pivot position of the upper frame 2220 and the lower frame 2230, and all are tilted upward from front to back.

[0141] It is evident that whether the seat body in forward-facing mode switches from the unfolded state to the first folded state, or the seat body in rear-facing mode switches from the unfolded state to the second folded state, the upper frame 2220 and the lower frame 2230 will eventually be positioned close to the pusher frame 2400, so that the folded seat body will not occupy too much space.

[0142] Referring to Figures 21A and 22A, when the seat body is in the unfolded state, it can rotate relative to the latching member 2210 as a whole, allowing the seat body to have multiple usage states (both forward and rearward modes) in the unfolded state. In different usage states, the upper frame 2220 and lower frame 2230, which are arranged on the same plane, have different tilt angles relative to the horizontal plane. In this embodiment, the seat body has a flat usage state (tilt angle of 0°), a first seat usage state, and a second seat usage state, with the tilt angles of the three usage states increasing sequentially. Figure 21A shows a schematic diagram of the seat frame 220 being installed on the upper frame 230 in the forward mode and the seat body being in the second seat usage state. At this time, the angle between the upper frame 2220 and the push handle 2400 is the smallest. Therefore, when the seat body is in the first folded state (as shown in Figure 21B), it is only necessary to pivot the lower frame 2230 toward the upper frame 2220. Figure 22A shows a schematic diagram of the seat frame 220 installed in a rearward configuration onto the upper frame 230 with the seat body in the second seat usage state. However, in this state, the upper frame 2220 does not reach the position with the smallest angle with the push handle 2400. Therefore, to reduce the volume occupied by the seat body after folding, the upper frame 2220 can be moved towards the lower frame 2230 to the position with the smallest angle with the push handle 2400, and the lower frame 2230 can be folded towards the upper frame 2220 and positioned close to the push handle 2400 to achieve the second folded state (as shown in Figure 22B). Figure 22A is a schematic diagram of the seat frame 20 of Figure 21A after being rotated 180° and installed onto the upper frame 230. Therefore, both Figure 22A and Figure 21A are in the second seat usage state.

[0143] When the seat frame 220 is installed on the upper frame 230 in a forward-facing mode and the seat body is in the first seat use state or the flat use state, the upper frame 2220 and the lower frame 2230 are located on both sides of the pusher frame 2400. Specifically, the lower frame 2230 and the front wheel 2131 are located on the same side of the pusher frame 2400, while the upper frame 2220 and the rear wheel 2131 are located on the same side of the pusher frame 2400. In order to reduce the volume occupied by the seat body after folding, the lower frame 2230 and the upper frame 2220 can also be folded towards each other and set near the pusher frame 2400 so that the seat body is in the first folded state.

[0144] When the seat frame 220 is installed on the upper frame 230 in a rearward configuration and the seat body is in the first seat use state or the flat use state, the upper frame 2220 and the lower frame 2230 are located on both sides of the pusher frame 2400. Specifically, the upper frame 2220 and the front wheel 2131 are located on the same side of the pusher frame 2400, while the lower frame 2230 and the rear wheel 2131 are located on the same side of the pusher frame 2400. In order to reduce the volume occupied by the seat body after folding, the lower frame 2230 and the upper frame 2220 can also be folded towards each other and set near the pusher frame 2400 so that the seat body is in the second folded state.

[0145] Referring to Figures 23 and 24, to achieve the above functions, this application pivotally connects one of the snap-fit ​​pieces 2210 to one end of the upper frame 2220 and one end of the lower frame 2230 via a pivot joint. Similarly, the other snap-fit ​​piece 2210 is pivotally connected to the other end of the upper frame 2220 and the other end of the lower frame 2230 via another pivot joint. Both pivot joints are identical. In other embodiments, the other snap-fit ​​piece 2210 can be pivotally connected to the other end of the upper frame 2220 and the other end of the lower frame 2230 without the aforementioned pivot joint. The following only describes how one pivot joint is pivotally connected to the corresponding snap-fit ​​piece 2210, one end of the upper frame 2220, and one end of the lower frame 2230.

[0146] Referring to Figures 23 and 24, the pivot joint includes a first pivot seat 2240, a second pivot seat 2250, a third pivot seat 2260, and a fourth pivot seat 2280 that pivot about the same axis. The direction of this axis is defined as the axial direction, the direction around this axis is defined as the circumferential direction, and the direction perpendicular to this axis is defined as the radial direction. The first pivot 2240, the second pivot 2250, the third pivot 2260, and the fourth pivot 2280 are arranged sequentially along the axial direction. That is, the second pivot 2250 is located between the first pivot 2240 and the third pivot 2260 along the axial direction, the third pivot 2260 is located between the second pivot 2250 and the fourth pivot 2280 along the axial direction, and the second pivot 2250 and the third pivot 2260 are both located between the first pivot 2240 and the fourth pivot 2280 along the axial direction. The first pivot 2240 is pivotally connected to the second pivot 2250, the second pivot 2250 is pivotally connected to the third pivot 2260, and the third pivot 2260 is pivotally connected to the fourth pivot 2280. The first pivot 2240, the second pivot 2250, the third pivot 2260, and the fourth pivot 2280 pivot in the circumferential direction.

[0147] Referring to Figures 23 and 24, the first pivot 2240 is connected to the snap-fit ​​2210, the second pivot 2250 is connected to the upper frame 2220, the third pivot 2260 is connected to the lower frame 2230, and the fourth pivot 2280 is connected to the handrail 2600, so as to realize the pivotal connection between the snap-fit ​​2210 and the upper frame 2220, the pivotal connection between the upper frame 2220 and the lower frame 2230, and the pivotal connection between the lower frame 2230 and the handrail 2600.

[0148] Further, referring to Figures 34A and 34B, the second pivot seat 2250 is provided with a second abutment portion 2258, and the third pivot seat 2260 is provided with a third abutment portion 2268 that is circumferentially opposite to the second abutment portion 2258. When the seat body is in the unfolded state, the second abutment portion 2258 and the third abutment portion 2268 abut against each other in the circumferential direction to help the upper frame 2220 and the lower frame 2230 remain on the same plane. In the embodiment shown, the second abutment portion 2258 is provided on the outer peripheral wall of the second pivot seat 2250, and the third abutment portion 2268 is provided on the outer peripheral wall of the third pivot seat 2260. It should be understood that the second abutting part 2258 and the third abutting part 2268 can also be provided at other positions of the second pivot seat 2250 and the third pivot seat 2260, as long as the second abutting part 2258 and the third abutting part 2268 can abut against each other circumferentially during the relative pivoting of the second pivot seat 2250 and the third pivot seat 2260.

[0149] Referring to Figures 25 to 29, to limit the relative pivoting of the seat frame 220's latching member 2210, upper frame 2220, lower frame 2230, and armrest frame 2600 when the seat body is in an unfolded state (including a reclining state, a first seat use state, and a second seat use state), a first folded state, and a second folded state, the pivot joint may also include a locking member 2270. The locking member 2270 can move between a locked position and an unlocked position. When the locking member 2270 is in the locked position, the first pivot seat 2240 and the second pivot seat... 2250, the third pivot 2260 and the fourth pivot 2270 cannot pivot relative to each other, so that the latch 2210, the upper frame 2220, the lower frame 2230 and the handrail 2600 cannot pivot relative to each other. However, when the locking member 2270 is in the unlocked position, the first pivot 2240, the second pivot 2250, the third pivot 2260 and the fourth pivot 2270 can pivot relative to each other, so that the latch 2210, the upper frame 2220, the lower frame 2230 and the handrail 2600 can pivot relative to each other.

[0150] Referring to Figures 27A and 27B, the locking member 2270 is movably disposed in the second pivot 2250, that is, the locking member 2270 is located between the first pivot 2240 and the third pivot 2260, and the locking member 2270 can move relative to the second pivot 2250 between a locked position and an unlocked position. When the locking member 2270 is in the locked position (as shown in Figures 27A and 34A), the locking member 2270 provided on the second pivot seat 2250 is simultaneously blocked by the first pivot seat 2240 and the third pivot seat 2260 in the circumferential direction (in both the positive and negative directions of the circumferential direction) (as shown in Figures 28, 29, 34A and 34D), so as to restrict the rotation of the second pivot seat 2250 relative to the first pivot seat 2240 and the third pivot seat 2260. That is, it simultaneously locks the relative pivot between the first pivot seat 2240 and the second pivot seat 2250 and the relative pivot between the second pivot seat 2250 and the third pivot seat 2260, thereby locking the relative pivot between the latching member 2210 and the upper frame 2220 and the relative pivot between the upper frame 2220 and the lower frame 2230. When the locking member 2270 is in the unlocked position (as shown in Figures 25, 27B, 34C, and 34B), the first pivot 2240 and the third pivot 2260 simultaneously release their obstruction of the locking member 2270 in the circumferential direction (at least in one of the two directions of the circumferential direction), allowing the locking member 2270 to rotate relative to at least one of the first pivot 2240 and the third pivot 2260 along with the second pivot 2250. That is, the locking between the first pivot 2240 and the second pivot 2250 and the locking between the second pivot 2250 and the third pivot 2260 are released simultaneously, thereby releasing the locking between the latch 2210 and the upper frame 2220 and the upper frame 2220 and the lower frame 2230.

[0151] It should be understood that in other embodiments, the pivot joint may only have a first pivot seat 2240, a second pivot seat 2250, and a third pivot seat 2260 arranged sequentially along the axial direction. This pivot joint can lock or release the relative positions of the first pivot seat 2240, the second pivot seat 2250, and the third pivot seat 2260 by moving the locking member 2270 between a locked position and an unlocked position. This locks relative pivoting between the first pivot seat 2240, the second pivot seat 2250, and the third pivot seat 2260 or releases the lock on pivoting between the first pivot seat 2240, the second pivot seat 2250, and the third pivot seat 2260. In this case, the pivot joint can be connected to three components that require relative pivoting.

[0152] Referring again to Figures 27A and 27B, the locking member 2270 can be installed on the side of the second pivot 2250 facing the first pivot 2240. The movement direction of the locking member 2270 intersects with the circumferential direction. In the embodiment shown, the locking member 2270 can move radially between a locked position and an unlocked position, that is, the movement direction of the locking member 2270 is radial. A radially extending groove 2251 can be provided in the second pivot 2250. The locking member 2270 can be slidably disposed in the groove 2251 in the radial direction. The groove 2251 can restrict the circumferential movement of the locking member 2270 relative to the second pivot 2250. It should be understood that a first limiting portion 22512 and a second limiting portion 22513 can be provided at both ends of the groove 2251 in its extending direction. When the locking member 2270 is in the locked position, one end of the locking member 2270 abuts against the first limiting portion 22512. When the locking member 2270 is in the unlocked position, the other end of the locking member 2270 abuts against the second limiting portion 22513. For example, the inner wall of the second pivot seat 2250 may form the first limiting portion 22512 or the second limiting portion 22513.

[0153] Referring again to Figures 27A and 27B, the locking member 2270 may have a central hole 2276, and the pivot joint is provided with a pivot shaft (not shown) passing axially through each pivot seat, the pivot shaft passing axially through the central hole 2276. The shape of the central hole 2276 may be configured such that the pivot shaft passing through it does not impede the movement of the locking member 2270 between the locked position and the unlocked position.

[0154] Referring to Figure 23, an operating member 2224 may also be provided on the upper frame 2220. The operating member 2224 is operably connected to the locking member 2270, for example, via a traction member (not shown) such as a cable. When operated, the operating member 2224 can move the locking member 2270 from the locked position to the unlocked position. In the embodiment shown, the operating member 2224 is located outside the top rod 2222 of the upper frame 2220 for user convenience. A cable is provided inside the top rod 2222 and the first rod 2221. One end of the cable is connected to the operating member 2224, and the other end is connected to the locking member 2270. When operated, the operating member 2224 can pull the locking member 2270 upwards via the cable, thereby moving the locking member 2270 from the locked position to the unlocked position. The locking member 2270 may be provided with a connecting hole 2275 (as shown in Figure 27B) for connection with a traction member (e.g., a cable).

[0155] Referring again to Figures 27A and 27B, the pivot joint is further provided with a reset member 2257 (e.g., an elastic member, such as a spring) located in the second pivot seat 2250. The reset member 2257 can bias the locking member 2270 toward the locking position, thereby moving or holding the locking member 2270 in the locking position without the action of external force. In the embodiment shown, the locking member 2270 is provided with an elongated hole 2277 extending along the moving direction of the locking member 2270. The second pivot seat 2250 is provided with a protrusion 2255 protruding into the elongated hole 2272. The reset member 2257 is disposed between the protrusion 2255 and the inner wall of the elongated hole 2277 and biases the locking member 2270 toward the locking position.

[0156] Referring to Figures 25, 27A, 27B, and 30, the locking member 2270 may be provided with a first locking portion 2271 protruding toward the first pivot seat 2240. The first locking portion 2271 is located on the side of the locking member 2270 facing the first pivot seat 2240. The side of the first pivot seat 2240 facing the second pivot seat 2250 may be provided with a plurality of locking slots spaced circumferentially and a first arc-shaped channel 2243 connecting the plurality of locking slots together. The channel formed by connecting the plurality of locking slots and the first arc-shaped channel 2243 is defined as a moving channel for the first locking portion 2271 to move. In the illustrated embodiment, the number of locking slots is four. Each locking slot extends along the moving direction of the locking member 2270, and the first arc-shaped channel 2243 extends circumferentially. In the illustrated embodiment, each locking slot extends radially, and the plurality of locking slots are all located on the same side of the first arc-shaped channel 2243 radially. When the locking member 2270 is in the locked position, the first locking part 2271 can engage in one of the multiple locking slots (see Figures 28 and 29). The first locking part 2271 is blocked by the groove wall of the corresponding locking slot in the circumferential direction (specifically in the two directions of the circumferential direction), thereby restricting the locking member 2270 and the second pivot seat 2250 from rotating in the circumferential direction relative to the first pivot seat 2240, thereby restricting the upper frame 2220 from rotating in the circumferential direction relative to the locking member 2210. When the locking member 2270 moves from the locked position to the unlocked position, the first locking part 2271 can disengage from the corresponding locking groove and enter the first arc-shaped channel 2243, so that the first locking part 2271 is not blocked by the first pivot seat 2240 in the circumferential direction (at least in one of the two circumferential directions), and can move circumferentially in the first arc-shaped channel 2243. This allows the locking member 2270 to rotate relative to the first pivot seat 2240 together with the second pivot seat 2250, thereby allowing the upper frame 2220 to pivot relative to the latching member 2210. When the upper frame 2220 pivots relative to the latching member 2210, the first locking part 2271 of the locking member 2270 can slide along the first arc-shaped channel 2243. After the first locking member 2271 rotates relative to the first pivot seat 2240, it will engage with one of the remaining locking slots due to the action of the reset member 2257, so as to restrict the locking member 2270 and the second pivot seat 2250 from rotating circumferentially relative to the first pivot seat 2240 again.

[0157] Referring to Figure 30, the four locking slots in the same moving channel include three first locking slots 2241 and one second locking slot 2242. The three first locking slots 2241 are arranged adjacent to each other. Optionally, the three first locking slots 2241 are spaced apart by the same circumferential distance. The circumferential distance between the second locking slot 2242 and the adjacent first locking slot 2241 is greater than the circumferential distance between two adjacent first locking slots 2241, and the second locking slot 2242 and the first locking slot 2241 away from the second locking slot 2242 are radially opposite to the two ends of the first arc-shaped channel 2243 in the circumferential direction.

[0158] Referring to Figures 27A, 27B, 28, and 29, the locking member 2270 also has another first locking part 2271 spaced circumferentially from the first locking part 2271. Correspondingly, the first pivot seat 2240 has another moving channel for the other first locking part 2271 to move, which makes the locking between the locking member 2270 and the first pivot seat 2240 more stable. The two first locking parts 2271 are arranged radially opposite each other and are located on opposite sides of the locking member 2270 in the moving direction of the locking member 2270.

[0159] Referring to Figures 26 and 30, a reinforcing piece 2247 is provided on the side of the first pivot 2240 facing the second pivot 2250. The locking groove of the first pivot 2240 is also formed on the reinforcing piece 2247. The reinforcing piece 2247 can increase the engagement stability between the first locking part 2271 and the locking groove of the first pivot 2240. In the illustrated embodiment, the portion of the first pivot 2240 excluding the reinforcing piece 2247 is made of plastic, while the reinforcing piece 2247 is made of metal. The locking groove is formed on both the plastic and metal materials, thereby enhancing the strength of the first pivot 2240 and preventing damage to the first pivot 2240 when the first locking part 2271 engages with the locking groove of the first pivot 2240.

[0160] Referring to Figures 26, 32, and 33, the locking member 2270 may be provided with a second locking portion 2272 protruding toward the third pivot seat 2260. The second locking portion 2272 is disposed on the side of the locking member 2270 facing the third pivot seat 2260. The side of the third pivot seat 2260 facing the second pivot seat 2250 may be provided with a plurality of locking grooves spaced apart circumferentially and a second arc-shaped channel 2263 connecting the plurality of locking grooves together. Each locking groove extends along the moving direction of the locking member 2270, and the second arc-shaped channel 2263 extends circumferentially. In the illustrated embodiment, each locking groove extends radially, and all locking grooves are located radially outside the second arc-shaped channel 2263. When the locking member 2270 is in the locked position, the second locking part 2272 can engage in one of the multiple locking grooves (see Figure 34A). The second locking part 2272 is blocked by the groove wall of the corresponding locking groove in the circumferential direction (specifically in the positive and negative directions of the circumferential direction), thereby restricting the locking member 2270 and the second pivot seat 2250 from rotating in the circumferential direction relative to the third pivot seat 2260, thereby restricting the upper frame 2220 from rotating in the circumferential direction relative to the lower frame 2230. When the locking member 2270 moves from the locked position to the unlocked position, the second locking part 2272 can disengage from the corresponding locking groove and enter the second arc-shaped channel 2263 (see Figure 34B). This allows the second locking part 2272 to move circumferentially within the second arc-shaped channel 2263 (see Figure 34C) without being obstructed by the third pivot seat 2260 (at least in one of the two circumferential directions). This allows the locking member 2270 to rotate relative to the third pivot seat 2260 together with the second pivot seat 2250, thereby allowing the upper frame 2220 to pivot relative to the lower frame 2230. After the second locking part 2272 rotates a certain angle relative to the third pivot seat 2260, it will engage with one of the remaining locking grooves due to the action of the reset member 2257 (see Figure 34D), thus again restricting the circumferential rotation of the locking member 2270 and the second pivot seat 2250 relative to the third pivot seat 2260.

[0161] In the embodiments shown in Figures 32, 34A to 34D, there are two locking slots. The two locking slots and the two ends of the second arc-shaped channel 2263 are radially opposite each other in the circumferential direction. When the second locking part 2272 engages with one of the locking slots, the seat body is in an unfolded state, and the upper frame 2220 and the lower frame 2230 are located on the same plane. When the second locking part 2272 engages with the other locking slot, the seat body is in a folded state, and the upper frame 2220 and the lower frame 2230 are parallel to each other. The locking slot engaged by the second locking part 2272 when the seat body is in the unfolded state is defined as the first locking slot 2261, and the locking slot engaged by the second locking part 2272 when the seat body is in the folded state is defined as the second locking slot 2262.

[0162] Referring to Figure 33, a through hole 2254 may be provided in the second pivot seat 2250, and the second locking part 2272 may extend through the through hole 2254 into any locking groove or the second arc-shaped channel 2263.

[0163] Referring to Figures 25, 34A-D, and 35, in some embodiments, the fourth pivot 2280 has a protrusion 2281 protruding toward the third pivot 2260 on the side facing the third pivot 2260. The third pivot 2260 has an arcuate through groove 2264 extending circumferentially (as shown in Figure 32). The second pivot 2250 has a third arcuate channel 2252 extending circumferentially on the side facing the third pivot 2260 (as shown in Figure 33). The arcuate through groove 2264 and the third arcuate channel 2252 at least partially overlap in a direction parallel to the axial direction. The protrusion 2281 of the fourth pivot 2280 extends through the arcuate through groove 2264 into the third arcuate channel 2252. The arcuate through groove 2264 has a fifth limiting end 22641 and a sixth limiting end 22642 in the circumferential direction. The third arc-shaped channel 2252 has a seventh limiting end 22521 and an eighth limiting end 22522. As shown in Figure 34A, when the seat frame 220 is in the unfolded state, the protrusion 2281 is clamped between the fifth limiting end 22641 and the seventh limiting end 22521. As shown in Figure 34D, when the seat frame 220 is in the folded state (whether in the first folded state or the second folded state), the protrusion 2281 is clamped between the sixth limiting end 22642 and the eighth limiting end 22522.

[0164] Referring to Figures 21A and 22A, when the seat body is in the unfolded state, the first locking part 2271 can engage in either of the first locking slots 2241 to lock the relative pivoting between the first pivot seat 2240 and the second pivot seat 2250, and the first locking part 2271 can disengage from the corresponding first locking slot 2241 to unlock the relative pivoting between the first pivot seat 2240 and the second pivot seat 2250. The three first locking slots 2241 correspond to the reclining use state, the first seat use state, and the second seat use state when the seat body is in the unfolded state. As mentioned above, Figure 21A shows a schematic diagram of the second seat use state when the seat body is in the unfolded state in the forward use mode. Figure 22A shows a schematic diagram of the second seat use state when the seat body is in the unfolded state in the rearward use mode. Figure 28 is a schematic diagram corresponding to Figure 21A, in which the locking member 2270 is in the locked position. Figure 29 is a schematic diagram corresponding to Figure 22A, in which the locking member 2270 is also in the locked position. The first locking part 2271 in Figure 28 or Figure 29 is located in the first locking slot 2241 of the second locking slot 2242 adjacent to the same moving channel. Regardless of whether it is the forward use mode or the rear use mode, when the first locking part 2271 is located in the first locking slot 2241 furthest from the second locking slot 2242 in the same movement channel, the seat body is in the unfolded reclining use mode; when the first locking part 2271 is located in the first locking slot 2241 in the middle of the three first locking slots 2241 in the same movement channel, the seat body is in the unfolded first seat use mode; when the first locking part 2271 is located in the first locking slot 2241 closest to the second locking slot 2242 in the same movement channel, the seat body is in the unfolded second seat use mode.

[0165] Referring to Figures 34A and 34B, as long as the seat body is in the unfolded state, whether it is in the reclining use state, the first seat use state, or the second seat use state, the second abutment portion 2258 of the second pivot seat 2250 abuts against the third abutment portion 2268 of the third pivot seat 2260 in the circumferential direction. This ensures that the relative positional relationship between the second pivot seat 2240 and the third pivot seat 2250 remains unchanged (i.e., the relative positional relationship between the lower frame 2230 and the upper frame 2220 remains unchanged), thereby ensuring that the second locking portion 2272 is engaged with the seat body. When in the unfolded state, all three parts can be engaged in the same locking groove. Since the relative positional relationship between the second pivot seat 2240 and the third pivot seat 2250 does not change, the protrusion 2281 can always be clamped between the fifth limiting end 22641 and the seventh limiting end 22521 when the seat body is in the unfolded state. In other words, the relative positional relationship between the second pivot seat 2240, the third pivot seat 2250 and the fourth pivot seat 2260 does not change (that is, the relative positional relationship between the lower frame 2230, the upper frame 2220 and the armrest frame 2600 does not change).

[0166] When it is necessary to adjust the angle of the seat body relative to the locking member 2210 in the unfolded state, taking the adjustment of the seat body angle from any seat use state to the reclining use state as an example, firstly, the user operates the operating member 2224 to pull the locking member 2270 from the locked position to the unlocked position. At this time, the first locking part 2271 of the locking member 2270 disengages from the current first locking groove 2241 of the first pivot seat 2240 and enters the first arc-shaped channel 2243, and the second locking part 2272 disengages from the first locking groove 2261 of the third pivot seat 2260 and enters the second arc-shaped channel 2263. Then, the user pushes the upper frame 2220 towards the ground, so that the first locking part 2271 is radially offset from the current first locking groove 2241, and releases the operating member 2224. At this time, since the first locking part 2271 cannot engage with any first locking groove 2241, the locking member 2270 will not return to the locked position. As the user continues to push the upper frame 2220 toward the ground, when the first locking part 2271 and the target first locking groove 2241 are radially opposite, under the action of the reset member 2257, the first locking part 2271 engages in the target first locking groove 2241, and the second locking part 2272 engages in the first locking groove 2261 (the reason is explained later), thereby completing the angle adjustment of the seat body relative to the docking member 2210. During the above process, when the user pushes the upper frame 2220 toward the ground, due to the abutting action of the second abutting part 2258 of the second pivot seat 2250 and the third abutting part 2268 of the third pivot seat 2260, the third pivot seat 2260 and the second pivot seat 2250 will not pivot relative to each other. Therefore, the second locking part 2272 is always radially opposite to the first locking groove 2261, whether the locking member 2270 is in the locked position or the unlocked position, so that when the locking member 2270 moves to the locked position, the second locking part 2272 can enter the first locking groove 2261 along the moving direction of the locking member 2270. Furthermore, the protrusion 2281 of the fourth pivot seat 2280 is always held between the fifth limiting end 22641 of the arc-shaped through groove 2264 of the third pivot seat 2260 and the seventh limiting end 22521 of the third arc-shaped channel 2252 of the second pivot seat 2250. Therefore, the entire seat body pivots synchronously with the pivoting of the upper frame 2220 toward the ground.

[0167] The process of adjusting the angle of the seat body from a reclining position to any other seating position is basically the same as the process of adjusting the angle of the seat frame 220 from any other seating position to a reclining position. The difference is that the user needs to push the upper frame 2220 away from the ground. During this process, the lower frame 2230 pivots towards the ground under the action of gravity until the second abutment portion 2258 of the second pivot seat 2250 abuts against the third abutment portion 2268 of the third pivot seat 2260, so that the second locking portion 2272 and the first locking groove 261 are radially opposite each other. At this time, when the first locking portion 2271 engages in the target first locking groove 2241, the second locking portion 2272 can still engage in the first locking groove 2261 along the moving direction of the locking member 2270, thereby completing the angle adjustment of the seat body relative to the locking member 2210.

[0168] Referring to Figures 21A, 22B, and 28, when the seat frame 220 is mounted forward on the upper frame 230 and the seat body needs to be pivoted from the second seat use state to the first folded state, firstly, the user operates the operating element 2224 to pull the locking element 2270 from the locked position to the unlocked position. At this time, the first locking part 2271 of the locking element 2270 disengages from the current first locking groove 2241 of the first pivot seat 2240 and enters the first arc-shaped channel 2243, and the second locking part 2272 disengages from the first locking groove 2261 of the third pivot seat 2260 and enters the second arc-shaped channel 2263. Then, the user pushes the lower frame 2230 toward the upper frame 2220, so that the second locking part 2272 is radially offset from the current first locking groove 2261, and releases the operating element 2224. At this time, since the second locking part 2272 cannot engage with any locking groove, the locking element 2270 will not return to the locked position. During this period, there is no need to pivot the upper frame 2220 toward the lower frame 2230, that is, the upper frame 2220 will not pivot relative to the latching member 2210, and the relative positional relationship between the upper frame 2220 and the latching member 2210 remains unchanged. Therefore, the first locking part 2271 is always radially opposite to the first locking groove 2241 of the second locking groove 2242 in the adjacent same moving channel. As the user continues to push the lower frame 2230 toward the upper frame 2220, the second locking part 2272 slides toward the second locking groove 2262 in the second arc-shaped channel 2263 until the second locking part 2272 and the second locking groove 2262 are radially opposite. Under the action of the reset member 2257, the first locking part 2271 engages with the first locking groove 2241 of the second locking groove 2242 in the adjacent same moving channel, and the second locking part 2272 engages with the second locking groove 2262 to reach the first folded state.

[0169] Referring to Figure 32, the second arc-shaped channel 2263 may have a third limiting end 22631 and a fourth limiting end 22632 to limit the maximum rotation angle of the second frame 2230 when transitioning between the unfolded state and the first folded state. The curvature of the second arc-shaped channel 2263 may be substantially equal to the sum of the angle of rotation of the lower frame 2230 relative to the upper frame 2220 and the angle corresponding to the circumferential length of the second locking part 2272 when the seat body transitions between the unfolded state and the first folded state.

[0170] Referring to Figures 34A to 34D, when the seat frame 220 is mounted forward on the upper frame 230, and the seat body needs to pivot from the second seat use state to the first folded state, the positional relationship between the protrusion 2281, the arc-shaped groove 2264, and the third arc-shaped channel 2252 is approximately as follows: When the lower frame 2230 begins to pivot towards the upper frame 2220, the fifth limiting end 22641 of the arc-shaped groove 2264 moves away from the protrusion 2281, causing the sixth limiting end 22642 of the arc-shaped groove 2264 to move closer to the protrusion 2281. However, the relative position of the protrusion 2281 and the seventh limiting end 22521 of the third arc-shaped channel 2252 remains unchanged until the arc-shaped groove 2264... The sixth limiting end 22642 of 4 abuts against the seventh limiting end 22521 of the third arc-shaped channel 2252 on the same side as the protrusion 2281, and pushes the protrusion 2281 to pivot together from the seventh limiting end 22521 of the third arc-shaped channel 2252 towards the eighth limiting end 22522 of the third arc-shaped channel 2252. At this time, the armrest frame 2600 begins to retract towards the upper frame 2220. When the protrusion 2281 abuts against the eighth limiting end 22522 of the third arc-shaped channel 2252, the protrusion 2281 is clamped between the sixth limiting end 22642 of the arc-shaped through groove 2264 and the eighth limiting end 22522 of the third arc-shaped channel 2252, so that the seat body is in the first folded state, as shown in Figure 34D.

[0171] When the seat body is in the first folded state, the user operates the operating element 2224 to pull the locking element 2270 from the locked position to the unlocked position. The first locking part 2271 can disengage from the first locking groove 2241, and at the same time, the second locking part 2271 can also disengage from the second locking groove 2262, thereby releasing the locking between the first pivot seat 2240 and the second pivot seat 2250, and between the second pivot seat 2250 and the third pivot seat 2260 in the first folded state. This allows the lower frame 2230 to pivot away from the upper frame 2220, and the relative pivoting between the second pivot seat 2250 and the third pivot seat 2260 can also drive the armrest frame 2600 to pivot, so that the seat body changes from the first folded state to the unfolded state. The process of the seat body changing from the first folded state to the unfolded state is the reverse of the process of the seat body changing from the unfolded state to the first folded state, and will not be described in detail here.

[0172] Referring to Figures 22A, 22B, and 29, when the seat frame 220 is rearwardly mounted on the upper frame 230, and it is necessary to pivot the seat body from the second seat use state to the second folding state, firstly, the user operates the operating element 2224 to pull the locking element 2270 from the locked position to the unlocked position. At this time, the first locking part 2271 of the locking element 2270 disengages from the current first locking groove 2241 of the first pivot seat 2240 and enters the first arc-shaped channel 2243, and the second locking part 2272 disengages from the first locking groove 2261 of the third pivot seat 2260 and enters... In the second arc-shaped channel 2263, the user pushes the upper frame 2220 toward the lower frame 2230 and the lower frame 2230 toward the upper frame 2220, so that the first locking part 2271 is radially offset from the current first locking groove 2241, the second locking part 2272 is radially offset from the locking groove 2261, and the operating member 2224 is released. At this time, since the first locking part 2271 cannot engage in any first locking groove 2241 and the second locking part 2272 cannot engage in any locking groove, the locking member 2270 will not return to the locked position. As the user continues to push the lower frame 2230 toward the upper frame 2220 and the upper frame 2220 toward the lower frame 2230, the first locking part 2271 slides toward the second locking groove 2242 in the first arc-shaped channel 2243, and the second locking part 2272 slides toward the second locking groove 2262 in the second arc-shaped channel 2263. When the first locking part 2271 and the second locking groove 2242 are radially opposite and the second locking part 2272 and the second locking groove 2262 are radially opposite, under the action of the reset member 2257, the first locking part 2271 engages in the second locking groove 2242, and the second locking part 2272 engages in the second locking groove 2262, so as to reach the second folded state.

[0173] If the user needs to pivot the seat body directly from the reclining position to the second folding position, firstly, the user operates the operating component 2224 to pull the locking component 2270 from the locked position to the unlocked position. At this time, the first locking part 2271 of the locking component 2270 disengages from the current first locking groove 2241 of the first pivot seat 2240 and enters the first arc-shaped channel 2243, and the second locking part 2272 disengages from the first locking groove 2261 of the third pivot seat 2260 and enters the second arc-shaped channel 2263. Then, the user pushes the upper frame 2220 towards the push arm 2400, so that the first locking part 2271 enters the first arc-shaped channel 224 between the first locking groove 2241 and the second locking groove 2242. After step 3, release the operating component 2224, and then the user continues to push the lower frame 2230 towards the upper frame 2220 and the upper frame 2220 towards the lower frame 2230, so that the first locking part 2271 slides towards the second locking groove 2242 in the first arc-shaped channel 2243 and the second locking part 2272 slides towards the second locking groove 2262 in the second arc-shaped channel 2263 until the first locking part 2271 and the second locking groove 2242 are radially opposite and the second locking part 2272 and the second locking groove 2262 are radially opposite. Under the action of the reset component 2257, the first locking part 2271 engages in the second locking groove 2242 and the second locking part 2272 engages in the second locking groove 2262 to reach the second folded state.

[0174] Referring to Figure 29, the first arc-shaped channel 2243 has a first limiting end 22431 and a second limiting end 22432 along its circumference to limit the maximum rotation angle of the first frame 2220 when switching between a lying-down use state and a second folded state. The curvature of the first arc-shaped channel 2243 can be substantially equal to the sum of the angle of rotation of the upper frame 2220 relative to the latching member 2210 and the angle corresponding to the circumferential length of the first locking part 2271 when the seat body is switched between a lying-down use state and a second folded state after the seat frame 220 is rearwardly mounted to the upper frame 230.

[0175] Referring to Figures 34A to 34D, when the seat frame 220 is rearwardly mounted on the upper frame 230, and the seat body needs to be moved from the second seat use state to the second folded state, the positional relationship between the protrusion 2281, the arc-shaped groove 2264, and the third arc-shaped channel 2252 is approximately as follows: When the lower frame 2230 begins to pivot towards the upper frame 2220, the fifth limiting end 22641 of the arc-shaped groove 2264 moves away from the protrusion 2281, causing the sixth limiting end 22642 of the arc-shaped groove 2264 to move towards... As the upper frame 2220 pivots toward the lower frame 2230 while moving toward the protrusion 2281, the seventh limiting end 22521 of the third arc-shaped channel 2252 moves away from the protrusion 2281, and the eighth limiting end 22521 of the third arc-shaped channel 2252 moves toward the protrusion 2281. When the protrusion 2281 is clamped between the sixth limiting end 22642 and the eighth limiting end 22522 of the arc-shaped groove 2264, the seat body is in the second folded state, as shown in Figure 34D. It can be seen that the curvature of the arc-shaped groove 2264 is approximately equal to the sum of the angle between the armrest 2600 and the lower frame 2230 when the seat body is in the unfolded state and the curvature corresponding to the circumferential dimension of the protrusion 2281. The curvature of the third arc-shaped channel 2252 can be basically equal to the sum of the angle between the armrest 2600 and the upper frame 2220 when the seat body is in the unfolded state and the curvature corresponding to the circumferential dimension of the protrusion 2281.

[0176] When the seat body is in the second folded state, the user operates the operating element 2224 to pull the locking element 2270 from the locked position to the unlocked position. The first locking part 2271 can disengage from the second locking groove 2242, and at the same time, the second locking part 2271 can also disengage from the second locking groove 2262, thereby releasing the locking between the first pivot seat 2240 and the second pivot seat 2250, and between the second pivot seat 2250 and the third pivot seat 2260 in the second folded state. This allows the lower frame 2230 and the upper frame 2220 to pivot away from each other. The relative pivoting between the second pivot seat 2250 and the third pivot seat 2260 can also drive the armrest frame 2600 to pivot, so that the seat body changes from the second folded state to the unfolded state. The process of the seat body changing from the second folded state to the unfolded state is the reverse of the process of the seat body changing from the unfolded state to the second folded state, and will not be described in detail here.

[0177] In summary, the angle of the seat body can be adjusted between the reclining state, the first seat state, and the second seat state via the operating component 2224, and the seat body can also be folded and unfolded between the unfolded state and the folded state. Furthermore, the pivot joint of this application allows the seat body to be folded towards the adjacent push handle 2400 regardless of whether the seat frame 220 is mounted forward or rearward on the frame 2000.

[0178] Referring to Figures 36, 37, and 38, the upper ends of the front leg 2110 and the rear leg 2120 are pivotally connected to form a first pivot point 2101. In the unfolded state of the frame 2000, the front leg 2110, the rear leg 2120, and the supporting surface (e.g., the ground) of the frame 2000 can form a roughly triangular structure, thereby stably supporting the upper frame 230 and the seat frame 220 (see Figures 21A-B and 22A-B). Further, the lower frame 210 may include a connecting frame 2140, one end of which is pivotally connected to the lower end of the rear leg 2120 to form a second pivot point 2102, and the other end is pivotally connected to the front leg 2110 to form a third pivot point 2103. When the frame 2000 is in the unfolded state, the first pivot point 2101, the second pivot point 2102, and the third pivot point 2103 can be located at the three vertices of a virtual triangle, so that the front leg 2110, the rear leg 2120, and the connecting frame 2140 can form a roughly triangular shape, thereby making the frame 2000 more stably maintained in the unfolded state. Furthermore, the front leg 2110 itself is a foldable leg. Specifically, the front leg 2110 includes an upper frame section 21101 and a lower frame section 21102, which are pivotally connected to form a fourth pivot point 2104, allowing the front leg 2110 to be folded and unfolded around the fourth pivot point 2104. Thus, the upper frame section 21101, the lower frame section 21102, the connecting frame 2140, and the rear leg 2120 can form a four-bar linkage.

[0179] Specifically, the front stand 2110 may include two generally parallel and spaced-apart front legs 2111. Each front leg 2111 may include an upper segment 21111 and a lower segment 21112, with the lower end of the upper segment 21111 and the upper end of the lower segment 21112 pivotally connected to form a fourth pivot point 2104. The two upper segments 21111 form an upper frame segment 21101. The two lower segments 21112 form a lower frame segment 21102. The rear stand 2120 may include two generally parallel and spaced-apart rear legs 2121. The upper end of the upper segment 21111 and the upper end of the rear legs 2121 pivotally connected to form a first pivot point 2101. The connecting frame 2140 may include two generally parallel and spaced-apart support rods 2141. One end of the support rod 2141 is pivotally connected to the lower end of the rear foot rod 2121 to form a second pivot point 2102, and the other end is pivotally connected to the lower rod segment 21112 to form a third pivot point 2103. It can be understood that on the left and right sides of the trolley frame 2000, there are two first pivot points 2101, two second pivot points 2102, two third pivot points 2103, and two fourth pivot points 2104.

[0180] Furthermore, the frame 2000 also includes a pull rod 2150 fixedly mounted on the front leg 2111. The pull rod 2150 can be fixedly mounted between two fourth pivot points 2104. Thus, by pulling the pull rod 2150 upwards, the entire frame 2000 can be folded. Specifically, when the pull rod 2150 is pulled upwards, the upper frame section 21101 and the lower frame section 21102 will move closer to each other around the fourth pivot point 2104. While the upper frame section 21101 and the lower frame section 21102 move closer to each other, the upper frame section 21101 and the rear leg 2120 gradually move away from each other through the first pivot point 2101, and the connecting frame 2140 moves closer to the rear leg 2120 and the upper frame section 21101 through the first pivot point 2101, the third pivot point 2103 and the second pivot point 2102, thereby completing the overall folding of the frame 2000.

[0181] The trolley frame provided in this application adopts a four-bar linkage frame folding method, which is simple in structure and easy to operate.

[0182] The upper frame 230 can be installed on the upper frame section 21101. Specifically, the mounting seat 2300 can be installed on the upper frame section 21101. Thus, when the lower frame 210 is folded, the mounting seat 2300 can pivot synchronously with the upper frame section 21101, causing the upper frame 230 to fold together with the lower frame 210, thereby achieving the overall folding of the frame 2000. Referring to Figure 38, the seat body in the folded state folds together with the upper frame 230 and the lower frame 210, thereby achieving the overall folding of the stroller.

[0183] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0184] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A seat reversing mechanism for rotatably mounting a seat frame to a subframe, characterized in that, include: The pusher frame pivots between the first pusher position and the second pusher position; as well as The seat locking member moves between a seat locking position and a seat unlocking position. When the seat locking member is in the seat locking position, the seat locking member locks the relative rotation between the seat frame and the underframe. When the seat locking member is in the seat unlocking position, the seat frame is able to rotate relative to the underframe. Specifically, when the pusher arm is in the first pusher position, the seat locking member is in the seat locking position; when the pusher arm is in the second pusher position, the seat locking member is in the seat unlocking position; when the pusher arm pivots from the first pusher position to the second pusher position, it drives the seat locking member to move from the seat locking position to the seat unlocking position.

2. The seat reversing mechanism according to claim 1, characterized in that, It also includes a connecting assembly, through which the pusher arm drives the seat locking member to move, the connecting assembly comprising: The slider slides between a first sliding position and a second sliding position; When the pusher frame is in the first pusher position, the slider is in the first sliding position; when the pusher frame is in the second pusher position, the slider is in the second sliding position. When the pusher arm pivots from the first pusher position to the second pusher position, it drives the slider to slide from the first sliding position to the second sliding position. When the slider slides from the first sliding position to the second sliding position, it drives the seat lock to move from the seat lock position to the seat release position.

3. The seat reversing mechanism according to claim 2, characterized in that, The pusher frame includes a seat drive unit that drives the sliding member to slide. The seat drive unit includes a first surface. The sliding member includes an abutment portion that is slidably connected to the first surface. When the pusher frame pivots from the first pusher position to the second pusher position, the extending direction of the first surface intersects with and is not perpendicular to the sliding direction of the sliding member. The seat drive unit drives the abutment portion to slide along the first surface.

4. The seat reversing mechanism according to claim 3, characterized in that, The pusher frame rotates about an axis, and any direction perpendicular to the axis is radial. The slider slides along one of the radial directions, and the contact point between the abutment and the first surface is the intersection of the sliding direction of the slider and the first surface.

5. The seat reversing mechanism according to claim 3, characterized in that, The abutting part is cylindrical, and the first surface is tangent to the circumferential surface of the abutting part.

6. The seat reversing mechanism according to claim 3, characterized in that, When the pusher frame is in the first pusher position, the angle between the sliding direction of the slider and the extension direction of the first surface is greater than the angle between the sliding direction of the slider and the extension direction of the first surface when the pusher frame is in the second pusher position.

7. The seat reversing mechanism according to claim 3, characterized in that, The seat drive unit also includes a second surface connected to the first surface. When the pusher is in the second pusher position, the second surface is perpendicular to the sliding direction of the slider, and the abutting part abuts against the second surface.

8. The seat reversing mechanism according to claim 7, characterized in that, The pusher frame includes two pusher rods arranged opposite each other. The central axis of the two pusher rods defines the plane in which the pusher frame is located. The center line of the second surface is coplanar with the plane in which the pusher frame is located.

9. The seat reversing mechanism according to claim 7, characterized in that, The seat drive unit also includes a third surface connected to the second surface, and the third surface and the first surface are symmetrically arranged with respect to the center line of the second surface.

10. The seat reversing mechanism according to claim 7, characterized in that, The pusher frame rotates about an axis, and any direction perpendicular to the axis is radial. The second surface is perpendicular to one of the radial directions. When the pusher frame is in the second pusher position, the sliding direction of the slider overlaps with the radial direction perpendicular to the second surface.

11. The seat reversing mechanism according to claim 3, characterized in that, The pusher frame rotates about an axis, and when the pusher frame pivots from the first pusher position to the second pusher position, the abutment portion moves in a direction away from the axis.

12. The seat reversing mechanism according to claim 2, characterized in that, The sliding direction of the slider is parallel to the moving direction of the seat locking component.

13. The seat reversing mechanism according to claim 2, characterized in that, It also includes a connecting rod pivotally connected to the pusher frame, the connecting rod having a first pivot portion, the pusher frame having a second pivot portion, the first pivot portion and the second pivot portion being pivotally connected about an axis, the sliding member being disposed at the first pivot portion and sliding relative to the first pivot portion between a first sliding position and a second sliding position, the pusher frame having a seat drive portion, the seat drive portion being disposed at the second pivot portion and protruding toward the first pivot portion to drive the sliding member to slide.

14. The seat reversing mechanism according to claim 13, characterized in that, The connecting assembly further includes a first connector passing through the connecting rod, one end of the first connector being connected to the sliding member, the seat locking member being exposed on the connecting rod, and the other end of the first connector extending out of the connecting rod to be connected to the seat locking member.

15. The seat reversing mechanism according to claim 14, characterized in that, The connecting rod is also provided with a steering component, and the first connecting component is transformed by the steering component to be parallel to the moving direction of the seat locking component, so as to connect with the seat locking component.

16. The seat reversing mechanism according to claim 13, characterized in that, The seat reversing mechanism also includes a push-hand locking member, the first pivot portion and the second pivot portion together define a receiving space, the push-hand locking member is disposed in the receiving space and moves along the axial direction between a push-hand locking position and a push-hand releasing position; The push handle locking member includes a locking part. When the push handle locking member is in the push handle locking position, the locking part is simultaneously located at the first pivot part and the second pivot part, preventing relative pivoting between the first pivot part and the second pivot part. When the push handle locking member is in the push handle unlocking position, the locking part is separated from the second pivot part, and the second pivot part can pivot relative to the first pivot part.

17. The seat reversing mechanism according to claim 16, characterized in that, The pusher locking member is provided with a clearance hole for the seat drive unit to pass through. When the seat drive unit pivots with the pusher frame, the seat drive unit can pivot within the third clearance hole.

18. The seat reversing mechanism according to claim 16, characterized in that, The seat reversing mechanism further includes: The push-to-release mechanism is slidably disposed on the second pivot portion; and An operating component is mounted on the pusher frame and connected to the pusher release component via a second connector; When the operating component is in operation, it drives the push handle release component to slide through the second connecting component, thereby driving the push handle locking component to move from the push handle locking position to the push handle release position.

19. The seat reversing mechanism according to claim 18, characterized in that, The push-hand locking component further includes a release part, which is located on the side of the push-hand locking component facing the push-hand release part and protrudes toward the push-hand locking component. The release part has a first mating surface that is inclined relative to the axial direction. The push-to-release mechanism has a second mating surface that is inclined relative to the axial direction. The first mating surface contacts and engages with the second mating surface so that when the push-to-release mechanism moves under the operation of the operating member, it drives the push-to-lock mechanism to move from the push-to-lock position to the push-to-release position.

20. The seat reversing mechanism according to claim 1, characterized in that, The seat reversing mechanism includes a connecting seat for rotatably connecting the seat frame to the underframe, the connecting seat including a first seat body for connecting to the underframe and a second seat body for connecting to the seat frame, the second seat body being rotatably connected to the first seat body about an axis; The pusher frame includes two pusher rods arranged opposite each other, and the central axis of the two pusher rods defines the plane in which the pusher frame is located; When the pusher is in the first pusher position, there is an angle between the plane on which the pusher is located and the axis; when the pusher is in the second pusher position, the plane on which the pusher is located is coplanar with the axis, and the pusher can rotate around the axis.

21. The seat reversing mechanism according to claim 20, characterized in that, The first seat body is provided with a first locking hole, and the second seat body is provided with a second locking hole that is opposite to and communicates with the first locking hole. The seat locking member is movably disposed in the second locking hole. When the seat lock is in the seat locked position, a portion of the seat lock extends into the first locking hole; when the seat lock is in the seat unlocked position, the seat lock retracts from the first locking hole. The moving direction of the seat locking component is parallel to the axis and spaced apart from the axis.

22. A trolley comprising a lower frame, a seat frame, and a seat reversing mechanism as claimed in any one of claims 1 to 21, wherein the seat frame is capable of switching between a forward-facing mode and a rearward-facing mode relative to the lower frame when the seat locking member is in the seat unlocked position.

23. A pivot joint, comprising a first pivot seat, a second pivot seat, and a third pivot seat arranged sequentially along an axial direction, and a locking member movably disposed on the second pivot seat, characterized in that, The first pivot, the second pivot, and the third pivot pivot rotate circumferentially about the axial direction; The locking member moves relative to the second pivot between a locked position and an unlocked position; When the locking member is in the locked position, the locking member disposed on the second pivot seat is simultaneously blocked by the first pivot seat and the third pivot seat in the circumferential direction, thereby locking the relative pivoting between the first pivot seat, the second pivot seat, and the third pivot seat, and thus locking the pivot joint; and When the locking member is in the unlocked position, the first pivot and the third pivot simultaneously release their obstruction of the locking member in the circumferential direction, thereby releasing the lock on the relative pivoting between the first pivot, the second pivot and the third pivot, and thus unlocking the pivot joint.

24. The pivot joint according to claim 23, characterized in that, The locking member has a first locking part on the side facing the first pivot seat, and the first pivot seat has a locking groove on the side facing the second pivot seat. The locking member has a second locking part on the side facing the third pivot seat, and the third pivot seat has a locking groove and a second arc-shaped channel communicating with the locking groove on the side facing the second pivot seat. Both the locking groove and the locking slot extend along the moving direction of the locking member, and the second arc-shaped channel extends along the circumferential direction. The moving direction of the locking member intersects with the circumferential direction. as well as When the locking member is in the locked position, the first locking part is located in the locking groove and is blocked by the groove wall of the locking groove in the circumferential direction, while the second locking part is located in the locking groove and is blocked by the groove wall of the locking groove in the circumferential direction. When the locking member is in the unlocking position, the first locking part disengages from the locking groove, while the second locking part is located in the second arc-shaped channel.

25. The pivot joint according to claim 24, characterized in that, The third pivot seat has two locking grooves spaced apart along the circumferential direction on the side facing the second pivot seat. When the locking member is in the locked position, the second locking part is located in one of the two locking grooves.

26. The pivot joint according to claim 25, characterized in that, The first pivot seat has two locking slots spaced apart circumferentially on the side facing the second pivot seat, and a first arc-shaped channel connecting the two locking slots; when the locking member is in the locked position, the first locking part is located in one of the two locking slots and the second locking part is located in one of the two locking slots, or the first locking part is located in the other of the two locking slots and the second locking part is located in the other of the two locking slots; when the locking member is in the unlocked position, the first locking part is located in the first arc-shaped channel.

27. The pivot joint according to claim 23, characterized in that, The locking member has a first locking part on the side facing the first pivot seat, and the first pivot seat has a plurality of locking grooves spaced apart along the circumferential direction and a first arc-shaped channel connecting the plurality of locking grooves on the side facing the second pivot seat. The locking member has a second locking part on the side facing the third pivot seat, and the third pivot seat has a locking groove on the side facing the second pivot seat. Both the locking groove and the locking slot extend along the moving direction of the locking member, the first arc-shaped channel extends along the circumferential direction, and the moving direction of the locking member intersects with the circumferential direction. The second pivot seat is provided with a second abutment portion, and the third pivot seat is provided with a third abutment portion that is opposite to the second abutment portion in the circumferential direction; When the second abutting part and the third abutting part abut against each other in the circumferential direction and the locking member is in the locked position, the first locking part is located in one of the plurality of locking grooves and is blocked by the groove wall of the locking groove in the circumferential direction, while the second locking part is located in the locking groove and is blocked by the groove wall of the locking groove in the circumferential direction; when the second abutting part and the third abutting part abut against each other in the circumferential direction and the locking member is in the unlocked position, the first locking part is located in the first arc-shaped channel, while the second locking part disengages from the locking groove and is opposite to the locking groove along the moving direction of the locking member.

28. The pivot joint according to claim 23, characterized in that, The pivot joint further includes a fourth pivot seat, which is disposed along the axial direction on the side of the third pivot seat away from the second pivot seat, and the fourth pivot seat pivots relative to the second pivot seat and the third pivot seat along the circumferential direction; The fourth pivot seat is provided with a protrusion that passes through the third pivot seat and extends into the second pivot seat; When the locking member is in the locked position, the protrusion is held in the circumferential direction by the second pivot and the third pivot to restrict the fourth pivot from pivoting relative to the second pivot and the third pivot.

29. The pivot joint according to claim 23, characterized in that, When the locking element is in the unlocked position, the second pivot and the third pivot can pivot together relative to the first pivot, and the relative position between the second pivot and the third pivot remains unchanged during the pivoting process.

30. The pivot joint according to claim 23, characterized in that, When the locking member is in the unlocked position, the third pivot seat can pivot relative to the first pivot seat and the second pivot seat, and the relative position between the first pivot seat and the second pivot seat remains unchanged during the pivoting process.

31. The pivot joint according to claim 23, characterized in that, When the locking member is in the unlocked position, the second pivot seat and the third pivot seat can pivot relative to the first pivot seat respectively, and the relative positions of the first pivot seat, the second pivot seat and the third pivot seat change during the pivoting process.

32. The pivot joint according to claim 23, characterized in that, The pivot joint further includes a fourth pivot seat, which is disposed along the axial direction on the side of the third pivot seat away from the second pivot seat, and the fourth pivot seat pivots relative to the first pivot seat, the second pivot seat, and the third pivot seat along the circumferential direction; When the locking element is in the locked position, it locks the relative pivoting between the first pivot, the second pivot, the third pivot, and the fourth pivot; when the locking element is in the unlocked position, it releases the lock on the relative pivoting between the second pivot, the third pivot, and the fourth pivot.

33. A seat frame, characterized in that, Includes a snap-fit ​​connector, a seat body, and a pivot joint according to any one of claims 23 to 32, wherein, The snap-fit ​​connector is connected to the first pivot seat and is used to connect to the frame of the trolley; The seat body includes an upper frame connected to the second pivot seat and a lower frame connected to the third pivot seat, and the seat body is used to define a seating space.

34. The seat frame according to claim 33, characterized in that, Including the pivot joint according to claim 25, the seat body includes an unfolded state and a first folded state, wherein when the seat body is in the first folded state, the included angle between the upper frame and the lower frame is smaller than the included angle between the first frame and the second frame when the seat body is in the unfolded state; when the seat body is in the unfolded state and the locking member is in the locked position, the second locking part is located in one of the two locking grooves; when the seat body is in the first folded state and the locking member is in the locked position, the second locking part is located in the other of the two locking grooves; when the seat body is in the unfolded state or the first folded state and the locking member is in the locked position, the first locking part is located in the same locking groove.

35. The seat frame according to claim 34, characterized in that, Including the pivot joint according to claim 26, the seat body includes an unfolded state and a second folded state, wherein when the seat body is in the second folded state, the included angle between the first frame and the second frame is smaller than the included angle between the first frame and the second frame when the seat body is in the unfolded state; when the seat body is in the unfolded state and the locking member is in the locked position, the first locking part is located in one of the two locking slots and the second locking part is located in one of the two locking slots; when the seat body is in the second folded state and the locking member is in the locked position, the first locking part is located in the other of the two locking slots and the second locking part is located in the other of the two locking slots.

36. The seat frame according to claim 34, characterized in that, Including the pivot joint according to claim 27, the seat body includes an unfolded state, wherein when the seat body is in the unfolded state, the second abutting portion and the third abutting portion abut against each other in the circumferential direction, and the seat body has multiple usage states by pivoting relative to the latching member when in the unfolded state; the multiple usage states correspond one-to-one with the multiple locking slots; when the seat body is in one of the multiple usage states and the locking member is in the locked position, the first locking portion is located in the corresponding one of the multiple locking slots, and the second locking portion is located in the locking slot; When the seat body is in one of the multiple usage states and the locking member is in the unlocked position, the first locking part is located in the first arc-shaped channel, and the second locking part is opposite to the locking groove along the moving direction of the locking member.

37. The seat frame according to claim 33, characterized in that, Including the pivot joint according to claim 28, the seat body further includes an armrest frame, which is connected to the fourth pivot seat.

38. The seat frame according to claim 37, characterized in that, The third pivot seat is provided with an arc-shaped through groove for the protrusion to move along the circumferential direction, and the arc-shaped through groove has a fifth limiting end and a sixth limiting end in the circumferential direction; The second pivot seat is provided with a third arc-shaped channel for the protrusion to move along the circumferential direction, and the third arc-shaped channel has a seventh limiting end and an eighth limiting end in the circumferential direction; The seat body includes an unfolded state and a folded state. When the seat body is in the folded state, the angle between the first frame and the second frame is smaller than the angle between the first frame and the second frame when the seat body is in the unfolded state. When the seat body is in the unfolded state and the locking member is in the locked position, the protrusion is clamped in the circumferential direction by the fifth limiting end and the seventh limiting end; When the seat body is in the folded state and the locking member is in the locked position, the protrusion is clamped in the circumferential direction by the sixth limiting end and the eighth limiting end.

39. A trolley, characterized in that, The trolley includes a frame and a seat frame according to claim 34, the seat frame being mounted to the frame in a forward-facing configuration. The frame includes a push handle for a user to push the trolley. When the seat body is in the unfolded state, the upper frame and the push handle are located on the same side of the pivot joint, and the lower frame and the push handle are located on opposite sides of the pivot joint. When the seat body is in the first folded state, the upper frame, the lower frame, and the push handle are located on the same side of the pivot joint; or The trolley includes a frame and a seat frame according to claim 35, the seat frame being mounted to the frame in a rearward configuration, the frame including a push handle for a user to push the trolley, wherein when the seat body is in the unfolded state, the upper frame and the push handle are located on opposite sides of the pivot joint, and the lower frame and the push handle are located on the same side of the pivot joint; when the seat body is in the second folded state, the upper frame, the lower frame, and the push handle are located on the same side of the pivot joint.

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