CN106256650B

CN106256650B - Baby carriage frame

Info

Publication number: CN106256650B
Application number: CN201610904748.3A
Authority: CN
Inventors: 吴泽坚; 郑皇意
Original assignee: Shanghai Le Ruiying Ltd
Current assignee: Shanghai Le Ruiying Ltd
Priority date: 2016-10-18
Filing date: 2016-10-18
Publication date: 2022-05-31
Anticipated expiration: 2036-10-18
Also published as: CN106256650A

Abstract

The invention discloses a baby carriage framework, which at least comprises: a main beam, at least one front wheel set is arranged at the front section, and a pair of four connecting rod sets which face upwards and a pair of four connecting rod sets which extend obliquely downwards are symmetrically pivoted at the left and right sides of the rear section; a pair of handle connecting rods, one end of each handle connecting rod is connected with the pair of upward four-connecting-rod groups and rotates along with the pair of upward four-connecting-rod groups; a U-shaped handle, both ends of which are respectively connected with the pair of handle connecting rods; and the pair of rear wheel sets are symmetrically and respectively connected with the pair of downward and laterally obliquely extending four-connecting-rod sets from left to right. When the locking of the upward four-bar linkage is released, the upward four-bar linkage is overlapped by the self gravity to shorten the height and the length of the folded state, and when the upward four-bar linkage reaches the completely folded state, the locking of the downward obliquely extending four-bar linkage can be further released, so that the rear wheel set can rotate forwards and upwards along with the upward four-bar linkage, the width and the length of the baby carriage framework in the folded state are reduced, and the baby carriage framework is convenient to carry and store.

Description

Baby carriage frame

Technical Field

The present invention relates to a stroller frame, and more particularly, to a stroller frame that can be shortened in height, length, and width after unlocking.

Background

The frame of the baby carriage has various folding designs, for example, the frame of the umbrella carriage can be folded like an umbrella, but the length after folding is still quite long.

The framework of the baby carriage has an extremely large wheel set, so that the framework of the conventional or commercially available baby carriage cannot be folded to an ideal size, which causes troubles when a user carries and collects the baby carriage.

In view of the above, there is a need to provide a stroller frame that can be used in a stroller and has a reduced length, width and height after being folded, so as to solve the above-mentioned troubles of users.

Disclosure of Invention

In order to solve the above technical problems, an object of the present invention is to provide a stroller frame that can be shortened in height, length, and width after unlocking, thereby facilitating carrying and storage.

The invention is realized by the following modes:

a stroller frame comprising at least:

a main beam, at least one front wheel set is arranged at the front section, and a pair of four connecting rod sets which face upwards and a pair of four connecting rod sets which extend obliquely downwards are symmetrically pivoted at the left and right sides of the rear section;

a pair of handle links, each having one end connected to the pair of upward four-bar linkages and rotating with the pair of upward four-bar linkages, obliquely extending to the rear of the stroller frame when the pair of upward four-bar linkages are locked, and pivoting forward and stacking downward when the pair of upward four-bar linkages are unlocked;

a U-shaped handle, both ends of which are respectively connected with the pair of handle connecting rods; and

and the pair of rear wheel sets are symmetrically connected with the pair of downward laterally obliquely extending four-bar linkage respectively on the left and right.

As a further preferred embodiment of the present invention, the stroller frame further comprises a pair of carrier connection seats, the pair of carrier connection seats are symmetrically arranged on the pair of upward four-bar linkages from left to right, and each carrier connection seat has an insertable portion for detachably connecting a common child seat or a carrier.

As a further preferred embodiment of the present invention, the stroller frame of the present invention further comprises a pair of lockable handle joints, both ends of the U-shaped handle are connected to the pair of handle links by the pair of lockable handle joints to be suspended rearward, and each lockable handle joint is interlocked with each upward four-bar linkage to automatically unlock when each upward four-bar linkage is pivoted forward and folded downward.

As a further preferred embodiment of the present invention, a locking mechanism is respectively disposed in the pair of upward four-bar linkage.

As a further preferable embodiment of the present invention, the present invention further comprises a first release mechanism linked with the latch mechanism.

The clamping mechanism comprises an elastic component and a movable latch, the elastic component biases the movable latch towards the locking position, and the movable latch is enabled to clamp the corresponding upward four-bar linkage when in the opening state; the first release mechanism includes a flexible member and a movable member, the flexible member is connected between the movable latch and the movable member.

The first release mechanism further comprises a return spring connected to the movable assembly, and the movable assembly is automatically returned after being operated by the bias of the return spring.

The movable component is a pedal which is arranged at the rear lower part of the main beam, and a movable protective cover is arranged on the pedal and is biased by a spring to normally stay at a position which can prevent the pedal from being operated.

As a further preferred embodiment of the present invention, each of the four-bar linkages facing upward includes a rear section of the main beam, and:

an upper pivot seat having a front pivot point and a rear pivot point;

a front pivot arm, the upper end of which is pivoted with the front pivot point, and the lower section of which is pivoted with the main beam; and

a rear pivot arm, the upper end of which is pivoted to the rear pivot point and the lower end of which is pivoted to the main beam;

the main beam is provided with a middle pivot seat, and the lower end of the rear pivot arm is pivoted with the middle pivot seat.

And a damping rod is arranged below the main beam and is linked with the front pivot arm to slow down the speed of folding the upward four-link group forwards and downwards when the four-link group is unlocked.

The damping rod is pivoted at the lower ends of the main beam and the front pivot arm and used for slowing down the rotating speed of the front pivot arm.

As a further preferred embodiment of the present invention, the pair of downward laterally extending four-bar linkages includes:

a pair of left and right symmetrical pivot seats extending obliquely downwards and provided with a first pivot point and a second pivot point;

a pair of left and right symmetrical rear wheel seats, which is provided with a third pivot point and a fourth pivot point;

the sliding part is arranged on the rear section of the main beam in a sliding way;

the pair of first rear leg tubes are symmetrical left and right and comprise a telescopic sliding block and an outer tube, wherein the upper end of the telescopic sliding block is pivoted with the sliding piece, and the lower end of the telescopic sliding block is slidably sleeved in the outer tube; the upper end of the outer pipe is pivoted with the first pivot point, and the lower end of the outer pipe is pivoted with the third pivot point;

the upper ends of the second rear leg tubes are pivoted to the second pivot points, and the lower ends of the second rear leg tubes are pivoted to the fourth pivot points;

a pair of left and right symmetrical movable latches pressed by a spring, which are operatively disposed between the pivoting base extending obliquely downward and the second rear leg tube, and are biased by an elastic member to keep the second rear leg tube locked; and

a release device, which is arranged at the rear section of the main beam and is linked with the movable latch pressed by the spring.

The release device is a button or pull handle, one end of which is exposed for the operation of a user, and the other end of which is linked with a movable latch pressed by a spring.

The release device has a convex or concave part which is slidably abutted with the movable latch pressed by the spring

The release device has an inclined groove slidably engaging a movable latch biased by a spring.

The sliding part is provided with a pair of pivot holes which are symmetrical left and right, and the telescopic sliding blocks of the first rear leg pipes are symmetrically pivoted on the pair of pivot holes which are symmetrical left and right.

The sliding part is provided with a pair of hook parts which are symmetrical left and right, the lower side of the baby carriage framework is correspondingly provided with a pair of lugs which are symmetrical left and right, and the pair of hook parts which are symmetrical left and right are used for hooking the pair of lugs which are symmetrical left and right.

As a further preferred embodiment of the present invention, the present invention further comprises a pair of links and a pivot pin; the pair of connecting rods are respectively pivoted at the lower ends of the pair of upward four-connecting-rod groups; the sliding member has an elongated slot through which the pivot pin passes and the pair of links.

In a further preferred embodiment of the present invention, the pair of left and right symmetrical protrusions are disposed on a pair of connecting rods, and one end of each of the pair of connecting rods is pivotally connected to the lower side of the main beam, and the other end is pivotally connected to the lower end of the corresponding upward four-bar linkage.

As a further preferred embodiment of the present invention, the device further comprises a retractable latching component, which is biased by the elastic component to latch the releasing device.

The telescopic clamping components are linked with the upward four-connecting-rod groups.

The bottom end of each upward four-connecting-rod group is provided with a convex part which is in slidable press contact with the telescopic clamping component.

Compared with the prior art, the baby carriage framework has the following beneficial effects:

when the locking of the upward four-bar linkage is released, the upward four-bar linkage is overlapped by the self gravity to shorten the height and the length of the folded state, and when the upward four-bar linkage reaches the completely folded state, the locking of the downward four-bar linkage can be further released, so that the rear wheel set can rotate forwards and upwards along with the upward four-bar linkage, the width and the length of the baby carriage framework in the folded state are reduced, the baby carriage framework is convenient to carry and store, and the problem of trouble when a user carries and stores the baby carriage framework due to the overlarge folding size is solved.

Drawings

FIG. 1 is a perspective view of the stroller frame of the present invention in an open position;

FIG. 2 is a schematic view of the stroller frame in a folded state and an unfolded state;

FIG. 3 is a partial cross-sectional view of the stroller frame showing the four-bar linkage in an upward orientation;

FIG. 4 is a perspective view of the stroller frame illustrating a first release mechanism of the stroller frame according to the present invention;

FIG. 5 is a schematic plan view of the stroller frame illustrating the first release mechanism of the stroller frame according to the present invention;

FIG. 6 is a partial side view of the stroller frame shown in an open position in accordance with the present invention;

FIG. 7 is a schematic view of the stroller frame showing the release mechanism of the four-bar linkage extending obliquely downward and laterally;

FIG. 8 is a partial cross-sectional view of the stroller frame showing the four-bar linkage tilted downward and laterally;

FIG. 9 is a cross-sectional view of the stroller frame illustrating the operation of the release mechanism of the stroller frame;

FIG. 10 is a cross-sectional view of the stroller frame illustrating the operation of the four-bar linkage tilted downward and laterally;

FIGS. 11 (A) - (C) are schematic views of a stroller frame according to an alternative embodiment of the release mechanism of the stroller frame;

FIG. 12 is a perspective view of the stroller frame showing the sliding member thereof;

FIG. 13 is a partial perspective view of the stroller frame showing the bottom thereof according to the present invention;

FIG. 14 is a partial cross-sectional view of the stroller frame showing the release mechanism of the present invention;

fig. 15 is a rear perspective view of the stroller frame of the present invention in an open position.

[ description of main reference symbols ]

1	Main beam	2	Four-bar linkage with upward link
				3	Four-bar linkage extending obliquely towards lower side	4	Carrier connecting seat
5	Handle connecting rod	6	U-shaped handle
				7	Clamping mechanism	8	First release mechanism
9	Sliding member	11	Front wheel group
				12	Rear wheel group	13	Middle pivot seat
14	Damping rod	21	Upper pivot seat
				22	Front pivot arm	23	Rear pivot arm
31	Pivot base extending obliquely towards lower side	32	First pivot point
				33	Second pivot point	34	Rear wheel seat
35	Third pivot point	36	The fourth pivot point
				37	First rear leg tube	38	Second rear leg tube
39	Spring-biased latch	61	Lockable handle joint
				71	Elastic component	72	Movable bolt
81	Flexible assembly	82	Movable assembly
				83	Reset spring	84	Movable protective cover
91	Pivot hole	92	Hook part
				93	Bump	94	Connecting rod
95	Elongated slot	96	Pivot pin
				211	Front pivot point	212	Rear pivot point
371	Telescopic slide block	372	Outer tube
				100	In the open state	120	Position of use
200	In the folded state	391	Release device
				392	Convex part	393	Concave part
394	Inclined ditch	395	Raised part
				396	Telescopic clamping component	700	A locked position.

Detailed Description

As shown in fig. 1, an embodiment of a stroller frame according to the present invention at least comprises a main beam 1, a pair of upward four-bar linkages 2, a pair of downward-inclined four-bar linkages 3, a pair of vehicle connecting seats 4, a pair of handle links 5, a U-shaped handle 6 and a pair of rear wheel sets 12.

Wherein, the front section of the main beam 1 can be provided with at least one front wheel set 11, and the rear section of the main beam 1 is symmetrically pivoted with a pair of four connecting rod sets 2 which face upwards and a pair of four connecting rod sets 3 which extend obliquely towards the lower side. When locked, the four-bar linkages remain in an open position 100, and when unlocked, pivot forward to a collapsed position 200, as shown in fig. 2.

The carrier connecting seat 4 is symmetrically arranged on the upward four-bar linkage 2 from left to right, and has a pluggable part for detachably connecting a common baby seat or a carrier.

Each handle link 5 has one end connected to the upward four-link group 2 to rotate with the upward four-link group 2, and is obliquely extended toward the rear of the stroller frame when each upward four-link group 2 is locked, and is pivoted forward to be overlapped downward when each upward four-link group 2 is unlocked, so that the length and height of the stroller frame of the present invention are shortened.

Two ends of the U-shaped grip 6 are respectively provided with a lockable grip joint 61 which is connected with each grip connecting rod 5 and is suspended to the rear; each lockable handle joint 61 is interlocked with the corresponding upward four-bar linkage 2, and automatically unlocks when each upward four-bar linkage 2 pivots forward and is folded downward, so that the U-shaped handle 6 can freely rotate and droop by the gravity of the U-shaped handle, and the length and the height of the baby carriage framework are further shortened.

The rear wheel set 12 is connected to each of the four-bar linkages 3 extending obliquely downward in left and right symmetry, and is held in a rear wheel use position 120 when the four-bar linkages 3 extending obliquely downward are locked in the expanded state 100. When the downward and laterally extending four-bar linkage 3 is released from locking, the rear wheel set 12 is forwardly and upwardly displaced to the folded state 200 with the downward and laterally extending four-bar linkage 3, thereby shortening the width and height of the stroller frame of the present invention.

As shown in fig. 3, a detent mechanism 7 is disposed in each of the four-bar linkages 2. The detent mechanism 7 can move to a locking position 700, so that the corresponding upward four-bar linkage 2 cannot pivot to keep the stroller frame of the present invention in the open state 100.

As shown in fig. 4 and 5, the stroller frame of the present invention can further comprise a first release mechanism 8 linked with the latch mechanism 7; when the first release mechanism 8 is operated, the detent mechanism 7 can be moved away from the locking position 700, so that the corresponding upward four-bar linkage 2 is unlocked, and when unlocked, the four-bar linkage can be pivoted forward to a folded state 200, as shown in fig. 2.

The locking mechanism 7 of this embodiment includes an elastic component 71 and a movable latch 72. Wherein the resilient member 71 biases the movable latch 72 toward the locking position 700 of the movable latch 72, and the open state 100 allows the movable latch 72 to catch the corresponding four-bar linkage 2 facing upward.

The first release mechanism 8 includes a flexible member 81, a movable member 82 and a return spring 83. The flexible assembly 81 is connected between the movable latch 72 and the movable assembly 82; when the movable element 82 is operated, the movable latch 72 can be moved away from the locking position 700 by the flexible element 81. The return spring 83 allows automatic return after the movable assembly 82 is operated.

The movable element 82 may be implemented as a pedal disposed behind and below the main beam 1, and a movable protective cover 84 is disposed on the pedal. The movable protective cover 84 is spring biased to normally stay in a position that blocks the pedal from being operated. Therefore, before the operator operates the pedal, the movable protective cover 84 must be removed or lifted first to prevent the operator from accidentally touching the pedal and accidentally unlocking the corresponding upward four-bar linkage 2 by the detent mechanism 7.

As shown in fig. 6, each upward four-bar linkage 2 includes a rear section of the main beam 1, and an upper pivot base 21, a front pivot arm 22 and a rear pivot arm 23. Wherein, the upper pivot base 21 is provided with a front pivot point 211 and a rear pivot point 212, the upper end of the front pivot arm 22 is pivoted with the front pivot point 211, and the lower section of the front pivot arm 22 is pivoted with the main beam 1, and the tail end exceeds the main beam 1 and is suspended for a certain length; the upper end of the rear pivot arm 23 is pivoted to the rear pivot point 212, and the lower end is pivoted to the main beam 1.

As shown in fig. 6, a middle pivot base 13 is provided at the rear end of the main beam 1, and the lower ends of the two rear pivot arms 23 are pivotally connected to the middle pivot base 13. Preferably, a damping rod 14 is provided under the main beam 1 to link with the front pivot arm 22, so as to slow down the speed of the forward pivoting and downward stacking of the four-bar linkages when the four-bar linkages are unlocked. More specifically, the damping rod 14 may be pivoted to the lower ends of the main beam 1 and the front pivot arm 22 to slow down the rotation speed of the front pivot arm 22, so as to prevent the upper and lower rods from colliding with each other due to too fast folding of the stroller frame.

As shown in fig. 7 to 10, the pair of four-bar linkages 3 extending obliquely downward includes a pair of left and right symmetrical pivot seats 31 extending obliquely downward, a pair of left and right symmetrical rear wheel seats 34, a sliding member 9, a pair of left and right symmetrical first rear leg tubes 37, a pair of left and right symmetrical second rear leg tubes 38, a pair of left and right symmetrical movable latches 39 pressed by springs, and a releasing device 391. Wherein a first pivot point 32 and a second pivot point 33 are provided on the pivot seat 31 extending obliquely downward; a third pivot point 35 and a fourth pivot point 36 are disposed on the rear wheel seat 34.

The sliding part 9 can be arranged on the rear section of the main beam 1 in a sliding way; the first rear leg tube 37 includes a telescopic slider 371 and an outer tube 372. The upper end of the telescopic slider 371 is pivoted to the sliding member 9, and the lower end is slidably sleeved in the outer tube 372. The upper end of the outer tube 372 is pivoted to the first pivot point 32, and the lower end is pivoted to the third pivot point 35; when the lock of the corresponding four-bar linkage 3 which extends obliquely downward and laterally is released and rotates forward and upward, the telescopic slider 371 rotates along with the outer tube 372, so that the slider 9 is pulled in the direction of the rear end of the main beam 1.

The upper end of the second rear leg tube 38 is pivotally connected to the second pivot point 33, and the lower end is pivotally connected to the fourth pivot point 36. A spring biased movable latch 39, operatively disposed between the downwardly angled pivot mount 31 and the second rear leg tube 38, is biased by a resilient member to remain locked to the second rear leg tube 38, thereby locking the corresponding downwardly angled four-bar linkage 3 in the open position 100.

The releasing device 391 is arranged at the rear section of the main beam 1 and is linked with the movable latch 39 which is pressed by the spring. When the releasing device 391 is operated, the movable latch 39 pressed by the spring is linked to release the locking of the second rear leg tube 38, so that the corresponding four-bar linkage 3 extending obliquely downward can drive the corresponding rear wheel set 12 to move forward and upward, thereby shortening the width and height of the stroller frame.

The release device 391 implemented in accordance with the present invention may be a button or pull handle with one end exposed for user operation and the other end coupled to the movable latch 39 which is spring biased. When the releasing device 391 is operated, the movable latch 39 pressed by the spring can be driven to release the clamping of the second rear leg tube 38, so that the corresponding four-bar linkage 3 extending obliquely downward can drive the corresponding rear wheel set 12 to move forward and upward, thereby shortening the width and height of the stroller frame.

As illustrated in fig. 11 (a), the way of linking the releasing device 391 with the movable latch 39 pressed by the spring may include a protrusion 392 slidably abutting against the movable latch 39 pressed by the spring, and when operated, the protrusion 392 is used to drive the movable latch 39 pressed by the spring, thereby releasing the catch of the second rear leg tube 38.

As illustrated in fig. 11 (B), the way of linking the releasing device 391 with the movable latch 39 pressed by the spring may also include a concave portion 393 slidably abutting against the movable latch 39 pressed by the spring, and when operated, the concave portion 393 drives the movable latch 39 pressed by the spring, thereby releasing the clamping of the second rear leg tube 38.

As shown in fig. 11 (C), the releasing device 391 may be linked with the movable latch 39 pressed by the spring, and may further include a groove 394 slidably receiving the movable latch 39 pressed by the spring, and when operated, the groove 394 is used to drive the movable latch 39 pressed by the spring, thereby releasing the second rear leg tube 38.

As shown in fig. 12, the sliding member 9 is provided with a pair of left and right symmetrical pivot holes 91, and the telescopic sliding blocks 371 of the first rear leg tubes 37 are pivoted on the left and right symmetrical pivot holes 91 in a left-right symmetrical manner, so that the four-bar linkage 3 extending obliquely downward keeps left-right symmetrical and synchronous rotation during rotation.

In addition, in order to prevent the rear wheel set 12 from being suddenly released in the folded state 200, the sliding member 9 may be provided with a pair of left and right symmetrical hooks 92, and the lower side of the stroller frame is correspondingly provided with a pair of left and right symmetrical protrusions 93; when each of the four-bar linkages 3 extending obliquely downward moves forward and upward to the folded state 200, the telescopic slider 371 of the first rear leg tube 37 just pulls the sliding member 9 to the end of the stroke, and the left and right symmetrical hook portions 92 hook the left and right symmetrical protrusions 93, so that the four-bar linkages 3 extending obliquely downward cannot be separated from the folded state 200, and the rear wheel sets 12 are prevented from being opened arbitrarily.

As shown in fig. 13, more specifically, the left and right symmetrical protrusions 93 may be disposed on a pair of connecting rods 94, and one end of each of the two connecting rods 94 is pivotally connected to the lower side of the main beam 1, and the other end is pivotally connected to the lower end of the corresponding upward four-bar linkage 2; when the corresponding upward four-bar linkage 2 rotates from the folded state 200 to the opened state 100, the pair of left and right symmetrical protrusions 93 are taken away from the pair of left and right symmetrical hook portions 92, so that each downward-inclined four-bar linkage 3 is separated from the folded state 200.

For easier and more convenient operation of the vehicle, the user may wish to automatically return the rear wheel set 12 to its use position 120 when the four-bar linkage 2 is deployed in the open position 100. Referring to fig. 12 and 13, in the embodiment, the sliding member 9 is provided with a pair of long slots 95, a pivot pin 96 passes through the long slots 95 and the connecting rod 94, and the connecting rod 94 is pivoted at the lower end of the front pivot arm 22 of the upward four-link group 2, so that the upward four-link group 2 can be linked with the downward and laterally-extending four-link group 3 through the sliding member 9.

As shown in fig. 2 and 14, when the user pulls up the U-shaped handle 6 during the unfolding process, the user can lift the four-bar linkage 2 upward via the handle link 5, so that the front pivot arm 22 in fig. 14 rotates clockwise, and the link 94 pivoted to the lower end of the front pivot arm 22 pushes the pivot pin 96 toward the front end of the main beam 1 to pull the slider 9 in the left direction in the drawing. Since the sliding member 9 is pivotally connected to the telescopic slider 371 of each first rear leg tube 37, the sliding member 9 moving in the left direction in the figure will pull the first rear leg tube 37, so that the first rear leg tube 37 rotates counterclockwise, and thus the four-link group 3 extending obliquely downward is driven counterclockwise, and the rear wheel set 12 is moved back and down to the rear wheel use position 120.

In order to prevent the rear wheel set 12 from being separated from the rear wheel using position 120 due to the fact that a user accidentally touches the releasing device 391, a telescopic clamping component 396 is further arranged and is biased by a resilient component to clamp the releasing device 391, so that the releasing device 391 cannot be operated.

As shown in fig. 15, in order to meet the operation logic, the retractable latching assembly 396 is linked with each upward four-bar linkage 2, and the retractable latching assembly 396 is pressed when the upward four-bar linkage 2 pivots to the angle of the folded state 200, so as to automatically release the latching of the releasing device 391.

More specifically, in this embodiment, a protruding portion 395 may be disposed at the bottom end of the upward four-bar linkage 2 to slidably press against the retractable latching assembly 396, and when each upward four-bar linkage 2 pivots to the angle of the folded state 200, the protruding portion just presses against the retractable latching assembly 396 to release the latching of the releasing device 391. Therefore, the user can operate the releasing device 391 to release the catch of the second rear leg tube 38 only when each upward four-bar linkage 2 is completely in the folded state 200, so that the two rear wheel sets 12 can be moved forward and upward to the folded state 200, thereby shortening the width and height of the stroller frame.

Claims

1. A stroller frame, comprising at least:

the pair of rear wheel sets are symmetrically and respectively connected with the pair of downward and laterally obliquely extending four-connecting-rod sets left and right;

the pair of downward-side-obliquely-extending four-bar linkages comprises:

the upper ends of the second rear leg tubes are pivoted to the second pivot point, and the lower ends of the second rear leg tubes are pivoted to the fourth pivot point; a pair of left and right symmetrical movable latches pressed by a spring, operatively disposed between the pivot base extending obliquely downward and the second rear leg tube, and biased by an elastic member to keep locking the second rear leg tube; and

and the release device is arranged at the rear section of the main beam and is linked with the movable latch pressed by the spring, and when the release device is operated, the release device can be linked with the movable latch pressed by the spring to release the clamping of the second rear leg tube, so that the corresponding four-link group which extends downwards and laterally in an inclined way can drive the corresponding rear wheel set to move forwards and upwards, and the width and the height of the baby carriage framework are shortened.

2. The stroller frame according to claim 1, further comprising a pair of carrier connection seats, wherein the pair of carrier connection seats are symmetrically disposed on the pair of upward four-bar linkages at left and right sides, and have a portion capable of being inserted for detachably connecting the carrier.

3. The stroller frame of claim 1, further comprising a pair of lockable handle joints, wherein the two ends of the U-shaped handle are cantilevered rearward by the pair of lockable handle joints connecting the pair of handle links, and each lockable handle joint is linked to each of the upward four-bar linkages and automatically unlocked when each of the upward four-bar linkages is pivoted forward and folded downward.

4. The stroller frame according to claim 1, wherein a detent mechanism is provided in each of the pair of upward four-bar linkages.

5. The stroller frame of claim 4, further comprising a first release mechanism coupled to the latch mechanism.

6. The stroller frame according to claim 5, wherein the catch mechanism comprises a resilient member and a movable latch, the resilient member biasing the movable latch toward the locked position, the movable latch engaging the corresponding four-bar linkage in the open position; the first release mechanism includes a flexible member and a movable member, the flexible member is connected between the movable latch and the movable member.

7. The stroller frame of claim 6, wherein the first release mechanism further comprises a return spring coupled to the movable member, the return spring being biased to automatically return the movable member after the movable member is operated.

8. The stroller frame according to claim 6, wherein the movable member is a pedal disposed behind and below the main beam, and a movable protective cover is disposed on the pedal, the movable protective cover being biased by a spring to normally stay in a position to block the pedal from being operated.

9. The stroller frame of claim 1, wherein each of the four-bar linkages includes a rear section of the main rail, and:

an upper pivot seat having a front pivot point and a rear pivot point;

a back pivot arm, the upper end of which is pivoted to the back pivot point and the lower end of which is pivoted to the main beam.

10. The stroller frame of claim 9, wherein the main beam has a central pivot base, and the lower end of the rear pivot arm is pivotally connected to the central pivot base.

11. The stroller frame according to claim 9, wherein a damping bar is provided under the main beam to interlock with the front pivot arm for slowing the speed of the forward and downward folding when the four-bar linkage is unlocked.

12. The stroller frame of claim 11, wherein the damping lever is pivotally mounted to the lower ends of the main beam and the front pivot arm to slow the rotational speed of the front pivot arm.

13. The stroller frame of claim 1, wherein the release mechanism is a button or pull handle, one end of which is exposed for user operation and the other end of which is coupled to a spring biased latch.

14. The stroller frame of claim 1, wherein the release mechanism has a protrusion or recess that slidably abuts the spring biased latch.

15. The stroller frame of claim 1, wherein the release mechanism comprises a ramp slidably engaging a spring biased latch.

16. The stroller frame according to claim 1, wherein the sliding member has a pair of left and right symmetrical pivot holes, and the telescopic slider of each of the first rear leg tubes is pivoted to the pair of left and right symmetrical pivot holes.

17. The stroller frame according to claim 1, wherein the sliding member has a pair of left and right symmetrical hooks, and the lower side of the stroller frame has a pair of left and right symmetrical protrusions for hooking the pair of left and right symmetrical protrusions.

18. The stroller frame of claim 1, further comprising a pair of links and a pivot pin; the pair of connecting rods are respectively pivoted at the lower ends of the pair of upward four-connecting-rod groups; the sliding member has an elongated slot through which the pivot pin passes and the pair of links.

19. The stroller frame according to claim 17, wherein the pair of left and right symmetrical protrusions are provided on a pair of connecting rods, one end of each connecting rod is pivotally connected to the lower side of the main beam, and the other end of each connecting rod is pivotally connected to the lower end of the corresponding upward four-bar linkage.

20. The stroller frame of claim 1, further comprising a retractable catch assembly biased by a resilient member to catch the release mechanism.

21. The stroller frame of claim 20, wherein the retractable latch assembly is coupled to each of the four-bar linkages facing upward.

22. The stroller frame of claim 21, wherein a bottom end of each of the four upward linkages has a raised portion slidably contacting the retractable catch assembly.