Patent Description:
A carrier frame often adopts a foldable design for easily portable for a user. As such, the carrier frame can be expanded completely in a use state or be folded to a compact size in a non-use state for storage or portable.

Conventional carrier frames can be operated so that a front leg, a rear leg, and a handle of the carrier frame are folded. Therefore, there are foldable mechanisms between the front leg and the rear leg, between the front leg and the handle, or between the rear leg and the handle, respectively. As such, when the user wants to fold the carrier frame, the user must bend over to fold the front leg and the rear leg first and then fold the handle to complete the folding of the carrier frame. As a result, the aforesaid foldable design not only causes complicated folding processes since the user needs to use his hands to perform multiple folding operations, but also causes the user much inconvenience since it requires the user to bend over to fold the carrier frame.

For solving the aforesaid problems, it is necessary to develop a carrier frame having a simple folding process.

<CIT> discloses a stroller comprising a front frame, a rear frame, a pusher handle frame and a seat frame, the front and rear frames and the handle frame being pivoted together at their respective end portions, the seat frame being pivoted intermediate the ends of its side members to the front frame below said respective end portions and having a portion thereof extending toward the rear frame, the stroller further comprising links pivoted intermediate the ends of the rear frame and also being pivoted with relation to the rearwardly extending portion of the seat frame, and a second link pivoted at one end to the pusher handle frame above said respective end portions and at the other end to the seat frame at the rearwardly extending portion thereof, the second link comprising a past dead center connection when the stroller is erect and holding the frames against folding.

One purpose of the present invention is to provide a carrier frame that can be released and folded synchronously and has advantages that the carrier frame is easy to fold, has a simple structure, and is convenient to operate.

Another purpose of the present invention is to provide a carrier frame that can improve the operational stability of the carrier frame and has advantages that the carrier frame is easy to fold, has a simple structure, and is convenient to operate.

This is achieved by a carrier frame according to claim <NUM>. The dependent claims pertain to corresponding further developments and improvements. As will be seen more clearly from the detailed description following below, the claimed carrier frame provided by the present invention includes a first tubular member, a second tubular member and a third tubular member. The second tubular member is pivoted to the first tubular member. The third tubular member is pivoted to the second tubular member to form a pivot portion cooperatively with the first tubular member and the second tubular member. The carrier frame further includes a folding unit. The folding unit includes a pivot frame, a first rod, a linkage rod and a second rod. The pivot frame is hinged to the pivot portion and the second tubular member respectively. An end of the first rod is pivoted to the pivot frame at a first pivot point. Another end of the first rod is pivoted to the pivot frame at a second pivot point. An end of the linkage rod is pivoted to the first tubular member. Another end of the linkage rod is pivoted to the pivot frame at a third pivot point. An end of the second rod is pivoted to the third tubular member. Another end of the second rod is pivoted to the linkage rod at a fourth pivot point. The second pivot point, the third pivot point and the fourth pivot point are located at the same pivot axis. A folding of the first tubular member relative to the third tubular member drives the second rod via the linkage rod to be folded relative to the pivot frame, so as to fold the third tubular member relative to the second tubular member.

Compared with the prior art, the carrier frame of the present invention has the folding unit disposed thereon. The folding unit includes the pivot frame, the first rod, the linkage rod and the second rod. The pivot frame is pivoted to the pivot portion and the second tubular member. The end of the first rod is pivoted to the pivot frame at the first pivot point, and another end of the first rod is pivoted to the pivot frame at the second pivot point, so that the pivot frame and the first rod can cooperatively form a quadrilateral structure. The end of the linkage rod is pivoted to the first tubular member, and another end of the linkage rod is pivoted to the pivot frame at the third pivot point. The end of the second rod is pivoted to the third tubular member, and another end of the second rod is pivoted to the linkage rod at the fourth pivot point. The second pivot point, the third pivot point and the fourth pivot point are located at the same pivot axis, so as to make the pivot frame, the first rod and the second rod cooperatively form a linkage structure. Via the design in which the linkage rod drives the second rod to be folded relative to the pivot frame by the folding of the first tubular member relative to the third tubular member, the third tubular member can be folded relative to the second tubular member simultaneously, so as to achieve the purpose that the folding of the first folding tubular member relative to the third tubular member can drive the third tubular member to be folded relative to the second tubular member. In such a manner, the carrier frame of the present invention can be released and folded synchronously and have advantages that the carrier frame is easy to fold, has a simple structure, and is convenient to operate.

Preferably, the pivot frame includes a third rod connected to a fourth rod, the fourth rod connected to a fifth rod, and the fifth rod. The first rod is pivoted to the third rod at the first pivot point. The first rod is pivoted to the fifth rod at the second pivot point. The third rod is pivoted to the pivot portion.

Preferably, the second tubular member is connected to a joint where the fourth rod is connected to the fifth rod.

Preferably, the pivot frame and the first rod cooperatively form a trapezoid structure.

Preferably, the linkage rod has a recess for accommodating a location whereby the pivot frame is hinged to the pivot portion.

Preferably, the carrier frame further includes a guiderail. The guiderail is connected to the linkage rod, and the guiderail forms an upward handle structure when the first tubular member, the second tubular member and the third tubular member are folded relative to each other.

Preferably, the carrier frame further includes a first locking device for locking a rotation of the first tubular member relative to the third tubular member, and the first locking device is disposed on the pivot portion.

Specifically, the carrier frame further includes a fourth tubular member pivoted to the first tubular member, and a folding of the fourth tubular member relative to the first tubular member releases the first locking device.

Specifically, the first locking device includes a first pulling member, a pushing member, a first mounting base, a second mounting base and a locking member. The first tubular member is connected to the first mounting base. The third tubular member is connected to the second mounting base. The first mounting base is pivoted to the second mounting base. The locking member is movably disposed between the first mounting base and the second mounting base. The pushing member is located between the first mounting base and the locking member. The pushing member and the locking member abut against each other. An end of the first pulling member is connected to the pushing member, and when the first pulling member pulls the pushing member, the pushing member pushes the locking member to release the first mounting base from the second mounting base.

Specifically, a protrusion extends from the first mounting base toward the pushing member, and a ramped surface is formed on the pushing member corresponding to the protrusion. The end of the first pulling member is wound on the pushing member. The first pulling member pulls the pushing member to rotate for making the protrusion abut against the ramped surface, and the protrusion abuts against the ramped surface to make the pushing member push the locking member to move.

Specifically, the ramped surface is a spiral surface structure formed on the pushing member.

Specifically, a first winding slot is formed on the pushing member corresponding to the first pulling member, and the first pulling member is wound on the first winding slot.

Specifically, the first locking device further includes a first elastic member disposed between the second mounting base and the locking member.

Specifically, the locking member has an engaging tooth structure, a first tooth structure is formed on the first mounting base, and a second tooth structure is formed on the second mounting base. The first elastic member pushes the engaging tooth structure thereby for the engaging tooth structure to be engaged with the first tooth structure and the second tooth structure to lock the first mounting base and the second mounting base.

Specifically, the pushing member pushes the engaging tooth structure to overcome an elastic force of the first elastic member to be disengaged from the first tooth structure, to release the first mounting base from the second mounting base.

Specifically, the locking member is movable along a pivot shaft between the first mounting base and the second mounting base.

Specifically, the pushing member is movable along a pivot shaft between the first mounting base and the second mounting base.

Specifically, the first locking device further includes a driving member disposed through the first tubular member and the fourth tubular member and engaged with the fourth tubular member. Another end of the first pulling member is wound on the driving member, and a folding of the fourth tubular member relative to the first tubular member allows the driving member to rotate and pull the first pulling member.

Specifically, a second winding slot is formed on the driving member, and the first pulling member is wound on the second winding slot.

Specifically, the carrier frame further includes a locking structure locking the first tubular member and the fourth tubular member in a folded state.

Specifically, the locking structure includes a torsional spring. An end of the torsional spring is mounted on the driving member. Another end of the torsional spring has an engaging hook. A fixing pillar extends outward from the first tubular member. When the fourth tubular member is folded on the first tubular member, the driving member drives the engaging hook for the engaging hook to be engaged with the fixing pillar.

Specifically, an insertion slot corresponding to the torsional spring is formed on the driving member.

Specifically, the carrier frame further includes a second locking device disposed between the first tubular member and the fourth tubular member for locking a rotation of the fourth tubular member relative to the first tubular member.

Specifically, the second locking device includes a second pulling member, an engaging member, a mating member, a first fixing member, a second fixing member and an operating member. The first tubular member is connected to the first fixing member. The fourth tubular member is connected to the second fixing member. The first fixing member is connected to the second fixing member, the mating member is connected to the first fixing member. The engaging member is slidably disposed on the second fixing member. The engaging member is engaged with the mating member to lock the first tubular member and the fourth tubular member in an expanded state. An end of the second pulling member is connected to the operating member. Another end of the second pulling member is connected to the engaging member. The operating member is operated to disengage the engaging member from the mating member via the second pulling member.

Specifically, the first fixing member and the second fixing member are fitted with and pivoted to each other.

Specifically, the second locking device further includes a second elastic member. The second elastic member provides an elastic force for making the engaging member engaged with the mating member.

Specifically, a pillar extends from the engaging member toward the mating member. An engaging hole structure is formed on the mating member corresponding to the pillar.

Specifically, when the fourth tubular member is folded on the first tubular member, the first tubular member and the fourth tubular member cooperatively form a support foot structure.

Specifically, the fourth tubular member is pivoted to the first tubular member. The fourth tubular member is foldable relative to the first tubular member. The carrier frame further includes a locking structure locking the first tubular member and the fourth tubular member in a folded state.

Preferably, the locking structure includes a torsional spring. An end of the torsional spring is mounted on a driving member located at the fourth tubular member. Another end of the torsional spring has an engaging hook, and a fixing pillar extends outward from the first tubular member. When the fourth tubular member is folded on the first tubular member, the driving member drives the engaging hook to be engaged with the fixing pillar.

Specifically, an insertion slot is formed on the driving member for placing the torsional spring.

Specifically, after the fourth tubular member is folded on the first tubular member, the first tubular member and the fourth tubular member cooperatively form a support foot structure.

Compared with the prior art, since the carrier frame of the present invention includes the locking structure disposed between the first tubular member and the fourth tubular member for locking the first tubular member and the fourth tubular member in a folded state, the present invention can prevent accidental expanding of the carrier frame during the transportation process, improves folding stability of the carrier frame, and has advantages that the carrier frame has a simple structure and is convenient to use.

The embodiments of the present invention will now be described with reference to the accompanying drawings.

Please refer to <FIG>. A carrier frame <NUM> provided by the present invention includes a first tubular member <NUM>, a second tubular member <NUM>, and a third tubular member <NUM>. The first tubular member <NUM> is pivoted to the second tubular member <NUM> to be foldable relative to the second tubular member <NUM>. The second tubular member <NUM> is pivoted to the third tubular member <NUM> to make the third tubular member foldable relative to the second tubular member <NUM>. The first tubular member <NUM>, the second tubular member <NUM> and the third tubular member <NUM> are pivoted at the same point to cooperatively form a pivot portion <NUM>. The carrier frame <NUM> further includes a folding unit <NUM>. The folding unit <NUM> includes a pivot frame <NUM>, a first rod <NUM>, a linkage rod <NUM>, and a second rod <NUM>. The pivot frame <NUM> is hinged to the pivot portion <NUM> and the second tubular member <NUM>. A pivot point between the pivot frame <NUM> and the pivot portion <NUM> and a pivot point between the pivot frame <NUM> and the second tubular member <NUM> are spaced away from each other. An end of the first rod <NUM> is pivoted to the pivot frame <NUM> at a first pivot point a, and another end of the first rod <NUM> is pivoted to the pivot frame <NUM> at a second pivot point b. The first pivot point a and the second pivot point b are spaced away from each other to make the pivot frame <NUM> and the first rod <NUM> cooperatively form a quadrilateral structure. An end of the linkage rod <NUM> is pivoted to the first tubular member <NUM>, and another end of the linkage rod <NUM> is pivoted to the pivot frame <NUM> at the third pivot point. The linkage rod <NUM> is a sheet-like structure and has a recess <NUM> for accommodating a location where the pivot frame <NUM> is hinged to the pivot portion <NUM>, so as to prevent interference between the linkage rod <NUM> and the pivot frame <NUM> to make each component of the carrier frame <NUM> more compact. An end of the second rod <NUM> is pivoted to the third tubular member <NUM>, and another end of the second rod <NUM> is pivoted to the linkage rod <NUM> at a fourth pivot point. The second pivot point b, the third pivot point and the fourth pivot point are located at the same pivot axis, so as to make the pivot frame <NUM>, the first rod <NUM> and the second rod <NUM> cooperatively form a linkage structure. Via a folding of the first tubular member <NUM> relative to the third tubular member <NUM>, the linkage rod <NUM> can fold the second rod <NUM> relative to the pivot frame <NUM>, so as to fold the third tubular member <NUM> relative to the second tubular member <NUM>. As such, the purpose that the folding of the first tubular member <NUM> relative to the third tubular member <NUM> can synchronously drive the third tubular member <NUM> to be folded relative to the second tubular member <NUM> is achieved. When the carrier frame <NUM> is folded, a rotation of the first tubular member <NUM> relative to the third tubular member <NUM> can simultaneously drive the second tubular member <NUM> and the third tubular member <NUM> to approach each other for completing the folding operation of the carrier frame <NUM>. Thus, since a user just needs to rotate the first tubular member <NUM> and then the third tubular member <NUM> can be folded relative to the second tubular member <NUM> synchronously, there is no need to further perform a folding of the second tubular member <NUM> and the third tubular member <NUM>, so as to improve the use convenience of the carrier frame <NUM>. The carrier frame <NUM> of the present invention is suitable for a foldable device, such as a scaffold, a folding ladder, a folding wheelchair and a stroller, but not limited thereto. More detailed description for an embodiment that the carrier frame <NUM> is applied to a stroller as shown in <FIG> is provided as follows. In this embodiment, the first tubular member <NUM> of the carrier frame <NUM> is a handle of the stroller, the second tubular member <NUM> is a front leg of the stroller, and the third tubular member <NUM> is a rear leg of the stroller. As such, the user can rotate the handle to move the front leg and the rear leg close to or away from each other for folding or expanding the carrier frame <NUM>. That is to say, the user can just operate the handle to complete the folding or expanding operation of the carrier frame <NUM>, so as to solve the prior art problem that the user must bend over to fold the front leg and the rear leg of the stroller. Thus, the operational convenience of the stroller is improved.

To be more specific, please refer to <FIG>. The pivot frame <NUM> includes a third rod <NUM>, a fourth rod <NUM>, and a fifth rod <NUM>. The first rod <NUM> is pivoted to the third rod <NUM> at the first pivot point a, the first rod <NUM> is pivoted to the fifth rod <NUM> at the second pivot point b, the third rod <NUM> is pivoted to the pivot portion <NUM>, and the second tubular member <NUM> is pivoted to a joint where the fourth rod <NUM> is connected to the fifth rod <NUM>. In such a manner, the first rod <NUM>, the second rod <NUM>, the third rod <NUM>, the fourth rod <NUM>, and the fifth rod <NUM> can cooperatively form a linkage mechanism. As such, the folding of the first tubular member <NUM> relative to the third tubular member <NUM> can drive the third tubular member <NUM> to be folded relative to the second tubular member <NUM> synchronously. Preferably, the pivot frame <NUM> could form a trapezoid structure cooperatively with the first rod <NUM>. In this embodiment, the pivot frame <NUM> and the first rod <NUM> cooperatively form a right-trapezoid-like structure.

Please refer to <FIG>, the carrier frame <NUM> provided by the present invention further includes a guardrail <NUM>. The guardrail <NUM> is connected to the linkage rod <NUM>. When the first tubular member <NUM>, the second tubular member <NUM>, and the third tubular member <NUM> are folded together relative to each other, the guardrail <NUM> forms an upward handle structure (as shown in <FIG>) for convenient transportation of the carrier frame <NUM>, so as to improve the use convenience of the carrier frame <NUM>.

Please refer to <FIG>. The carrier frame <NUM> further includes a first locking device <NUM> and a fourth tubular member <NUM>. The first locking device <NUM> is used to lock the rotation of the first tubular member <NUM> relative to the third tubular member <NUM>. The first locking device <NUM> is disposed on the pivot portion <NUM>. The fourth tubular member <NUM> is pivoted to the first tubular member <NUM>. The first locking device <NUM> can be released via a folding of the fourth tubular member <NUM> relative to the first tubular member <NUM>. In other words, there is no need to additionally dispose an operating member <NUM> on the first locking device <NUM>, which means that the user just needs to rotate the first tubular member <NUM> and the fourth tubular member <NUM> for releasing the first locking device <NUM>. For example, the first locking device <NUM> includes a first pulling member <NUM>, a pushing member <NUM>, a first mounting base <NUM>, a second mounting base <NUM>, a locking member <NUM>, and a first elastic member <NUM>. The first tubular member <NUM> is connected to the first mounting base <NUM>, the third tubular member <NUM> is connected to the second mounting base <NUM>, and the first mounting base <NUM> is pivoted to the second mounting base <NUM>. In such a manner, a rotation of the first mounting base <NUM> relative to the second mounting base <NUM> can drive the first tubular member <NUM> to rotate relative to the third tubular member <NUM>, and locking the first mounting base <NUM> and the second mounting base <NUM> can lock the rotation of the first tubular member <NUM> relative to the third tubular member <NUM>. The locking member <NUM> is movably disposed between the first mounting base <NUM> and the second mounting base <NUM>. The pushing member <NUM> is located between the first mounting base <NUM> and the locking member <NUM>. The pushing member <NUM> and the locking member <NUM> abut against each other. The first elastic member <NUM> is disposed between the second mounting base <NUM> and the locking member <NUM> and has a tendency to bias the locking member <NUM> against the first mounting base <NUM>, so as to make the pushing member <NUM> and the locking member <NUM> abut against each other. An end of the first pulling member <NUM> is connected to the pushing member <NUM>. When the fourth tubular member <NUM> is folded relative to the first tubular member <NUM>, the first pulling member <NUM> pulls the pushing member <NUM> to move the locking member <NUM> along a pivot shaft between the first pivot base <NUM> and the second pivot base <NUM>. The pushing member <NUM> moves along the pivot shaft between the first mounting base <NUM> and the second mounting base <NUM> for releasing the first mounting base <NUM> from the second mounting base <NUM>.

Please refer to <FIG> and <FIG>. A protrusion <NUM> extends from the first mounting base <NUM> toward the pushing member <NUM>, and a ramped surface <NUM> is formed on the pushing member <NUM> corresponding to the protrusion <NUM>. An end of the first pulling member <NUM> is wound on the pushing member <NUM>. The first pulling member <NUM> pulls the pushing member <NUM> to rotate, so as to make the protrusion <NUM> abut against the ramped surface <NUM>. As such, by abutting of the protrusion <NUM> against the ramped surface <NUM>, the pushing member <NUM> can push the locking member <NUM> to move. In other words, with a rotation of the pushing member <NUM>, abutting of the protrusion <NUM> against the ramped surface <NUM> can make the pushing member <NUM> move along the pivot shaft between the first mounting base <NUM> and the second mounting base <NUM>. Accordingly, the pushing member <NUM> can push the locking member <NUM> to move along the pivot shaft between the first mounting base <NUM> and the second mounting base <NUM> for locking or releasing the first mounting base <NUM> and the second mounting base <NUM>. The ramped surface <NUM> is a spiral surface structure formed on the pushing member <NUM>. In this embodiment, three protrusions <NUM> are formed on the first mounting base <NUM> and are symmetrically disposed relative to the pivot shaft between the first mounting base <NUM> and the second mounting base <NUM>. The three protrusions <NUM> are equally spaced on the first mounting base <NUM>. Correspondingly, three ramped surfaces <NUM> are formed on the pushing member <NUM> and are symmetrically disposed relative to the pivot shaft between the first mounting base <NUM> and the second mounting base <NUM>. The three ramped surfaces <NUM> are equally spaced on the pushing member <NUM>. Furthermore, a first winding slot <NUM> is formed on the pushing member <NUM> corresponding to the first pulling member <NUM>, and the first pulling member <NUM> is wound on the first winding slot <NUM> for preventing interference between each component of the carrier frame <NUM>, so as to make each component of the carrier frame <NUM> more compact. Preferably, the first pulling member <NUM> is a steel wire rope, but not limited thereto.

Please refer to <FIG>. The locking member <NUM> has an engaging tooth structure <NUM>, a first tooth structure <NUM> is formed in the first mounting base <NUM> corresponding to the engaging tooth structure <NUM>, and a second tooth structure <NUM> is formed in the second mounting base <NUM> corresponding to the engaging tooth structure <NUM>. The first elastic member <NUM> can push the engaging tooth structure <NUM> to be simultaneously engaged with the first tooth structure <NUM> and the second tooth structure <NUM> for locking the first mounting base <NUM> and the second mounting base <NUM>. On the other hand, the pushing member <NUM> can push the engaging tooth structure <NUM> to overcome an elastic force of the first elastic member <NUM>, so that the engaging tooth structure <NUM> can be disengaged from the first tooth structure <NUM> for releasing the first mounting base <NUM>. That is to say, when the engaging tooth structure <NUM> is simultaneously engaged with the first tooth structure <NUM> and the second tooth structure <NUM>, the engaging tooth structure <NUM> can lock a position of the first tooth structure <NUM> relative to the second tooth structure <NUM> for preventing the first mounting base <NUM> from rotating relative to the second mounting base <NUM>, so as to fix a pivot angle of the first tubular member <NUM> relative to the third tubular member <NUM>. When the engaging tooth structure <NUM> is pushed by the pushing member <NUM> to overcome the elastic force to be disengaged from the first tooth structure <NUM> and then completely engaged with the second tooth structure <NUM>, the engaging tooth structure <NUM> no longer constrains a position of the first tooth structure <NUM> relative to the second tooth structure <NUM>. As a result, the first mounting base <NUM> can be rotatable relative to the second mounting base <NUM> to achieve free rotation of the first tubular member <NUM> relative to the third tubular member <NUM>. In summary, the carrier frame <NUM> has a simple locking design and is easy to operate. Preferably, the engaging tooth structure <NUM> is formed in a circumferential distribution. Correspondingly, the first tooth structure <NUM> and the second tooth structure <NUM> are formed in a circumferential distribution, to make locking of the engaging tooth structure <NUM> more stable.

Please refer to <FIG> and <FIG>. The first locking device <NUM> further includes a driving member <NUM>. A first fixing member <NUM> is connected to the first tubular member <NUM>, and a second fixing member <NUM> is connected to the fourth tubular member <NUM>. The driving member <NUM> is disposed through the first fixing member <NUM> and the second fixing member <NUM>. The driving member <NUM> is engaged with the fourth tubular member <NUM>. Another end of the first pulling member <NUM> is wound on the driving member <NUM>. Via the folding of the fourth tubular member <NUM> relative to the first tubular member <NUM>, the driving member <NUM> can rotate accordingly to pull the first pulling member <NUM>, such that the first pulling member <NUM> can pull the pushing member <NUM> to rotate. Specifically, a second winding slot <NUM> is formed on the driving member <NUM> corresponding to the first pulling member <NUM>, and the first pulling member <NUM> is wound on the second winding slot <NUM> for preventing interference between each component of the carrier frame <NUM>, so as to make each component of the carrier frame <NUM> more compact.

Please refer to <FIG>, the carrier frame <NUM> provided by the present invention further includes a locking structure <NUM> to lock the first tubular member <NUM> and the fourth tubular member <NUM> in a folded state. For example, the locking structure <NUM> includes a torsional spring <NUM>. The driving member <NUM> is fixedly engaged with the fourth tubular member <NUM>. A rotation of the fourth tubular member <NUM> relative to the first tubular member <NUM> can drive the driving member <NUM> to rotate. An end of the torsional spring <NUM> is connected to the driving member <NUM> on the fourth tubular member <NUM>, and another end of the torsional spring <NUM> has an engaging hook <NUM>. A fixing pillar <NUM> extends outward from the first tubular member <NUM> corresponding to the engaging hook <NUM> and is formed on the first fixing member <NUM>. When the fourth tubular member <NUM> is folded relative to the first tubular member <NUM>, the driving member <NUM> drives the engaging hook <NUM> to be engaged with the fixing pillar <NUM>, so as to lock the first tubular member <NUM> and the fourth tubular member <NUM>. The first tubular member <NUM> and the fourth tubular member <NUM> can cooperatively form an anti-tip support foot structure after the fourth tubular member <NUM> is folded relative to the first tubular member <NUM>, so as to efficiently prevent the carrier frame <NUM> from tipping over after being folded. Specifically, an insertion slot <NUM> corresponding to the torsional spring <NUM> is formed on the driving member <NUM>. The torsional spring <NUM> can be mounted on the driving member <NUM> through the insertion slot <NUM> for preventing interference between the first pulling member <NUM> and the torsional spring <NUM>.

Please refer to <FIG> and <FIG>. The carrier frame <NUM> provided by the present invention further includes a second locking device <NUM>. The second locking device <NUM> is used to lock the rotation of the fourth tubular member <NUM> relative to the first tubular member <NUM>. The second locking device <NUM> is disposed between the first tubular member <NUM> and the fourth tubular member <NUM>. For example, the second locking device <NUM> includes a second pulling member <NUM>, an engaging member <NUM>, a mating member <NUM>, the first fixing member <NUM>, the second fixing member <NUM>, the operating member <NUM>, and a second elastic member <NUM>. The first tubular member <NUM> is connected to the first fixing member <NUM>. The fourth tubular member <NUM> is connected to the second fixing member <NUM>. The first fixing member <NUM> is fitted with and pivoted to the second fixing member <NUM>. The mating member <NUM> is fitted within the first fixing member <NUM> and is connected to the second fixing member <NUM>. The second elastic member <NUM> is disposed in the fourth tubular member <NUM>. An end of the second elastic member <NUM> is connected to the fourth tubular member <NUM>, and another end of the second elastic member <NUM> is disposed in and connected to the engaging member <NUM>. The engaging member <NUM> is slidably disposed on the second fixing member <NUM>. The second elastic member <NUM> provides an elastic force to make the engaging member <NUM> engaged with the mating member <NUM> for locking the first tubular member <NUM> and the fourth tubular member <NUM> in an expanded state. An end of the second pulling member <NUM> is connected to the operating member <NUM>, and another end of the second pulling member <NUM> is connected to the engaging member <NUM>. The second pulling member <NUM> is movable along an axial direction of the fourth tubular member <NUM>. The operating member <NUM> can be operated to pull the second pulling member <NUM>. Accordingly, the second pulling member <NUM> can pull the engaging member <NUM> to overcome the elastic force of the second elastic member <NUM> and then be disengaged from the mating member <NUM>. As a result, the second fixing member <NUM> is freely-rotatable relative to the first fixing member <NUM>, such that the fourth tubular member <NUM> can rotate freely relative to the first tubular member <NUM>. For example, a pillar extends from the engaging member <NUM> toward the mating member <NUM>, and an engaging hole structure is formed on the mating member <NUM> corresponding to the pillar. The pillar and the engaging hole structure can be engaged with each other, and a transverse cross-section of the engaging hole structure is in a rectangular shape.

In summary, please refer to <FIG>. The detailed description for the operations of the carrier frame <NUM> of the present invention is provided as follows.

When the user wants to fold the stroller in an expanded state as shown in <FIG>, the user can press the operating member <NUM> to drive the engaging member <NUM> via the second pulling member <NUM> to overcome the elastic force of the second elastic member <NUM>. Accordingly, the engaging member <NUM> can be disengaged from the mating member <NUM> to make the second fixing member <NUM> freely-rotatable relative to the first fixing member <NUM>, such that the fourth tubular member <NUM> can rotate freely relative to the first tubular member <NUM>. In such a manner, the fourth tubular member <NUM> can be folded relative to the first tubular member <NUM> to form an anti-tip support foot structure as shown in <FIG>. During the folding of the fourth tubular member <NUM> relative to the first tubular member <NUM>, the driving member <NUM> rotates accordingly to drive the engaging hook <NUM> to be engaged with the fixing pillar <NUM>, so as to lock the first tubular member <NUM> and the fourth tubular member <NUM> in a folded state. At the same time, a rotation of the driving member <NUM> can drive the first pulling member <NUM> to pull the pushing member <NUM>, such that the pushing member <NUM> can push the locking member <NUM> to move along the pivot shaft between the first mounting base <NUM> and the second mounting base <NUM>. When the engaging tooth structure <NUM> is pushed by the pushing member <NUM> to overcome the elastic force to be disengaged from the first tooth structure <NUM> and then completely engaged with the second tooth structure <NUM>, the engaging tooth structure <NUM> no longer constrains a position of the first tooth structure <NUM> relative to the second tooth structure <NUM> to make the first mounting base <NUM> rotatable relative to the second mounting base <NUM>, so as to achieve free rotation of the first tubular member <NUM> relative to the third tubular member <NUM>. The folding of the first tubular member <NUM> relative to the third tubular member <NUM> can drive the second rod <NUM> to be folded relative to the pivot frame <NUM> via the linkage rod <NUM>, so as to fold the third tubular member <NUM> relative to the second tubular member <NUM>. In such a manner, the purpose that the folding of the first tubular member <NUM> relative to the third tubular member <NUM> can synchronously drive the third tubular member <NUM> to be folded relative to the second tubular member <NUM> is achieved.

In summary, the carrier frame <NUM> of the present invention has the folding unit <NUM> disposed thereon. The folding unit <NUM> includes the pivot frame <NUM>, the first rod <NUM>, the linkage rod <NUM> and the second rod <NUM>. The pivot frame <NUM> is pivoted to the pivot portion <NUM> and the second tubular member <NUM>. The end of the first rod <NUM> is pivoted to the pivot frame <NUM> at the first pivot point a, and another end of the first rod <NUM> is pivoted to the pivot frame <NUM> at the second pivot point b, so that the pivot frame <NUM> and the first rod <NUM> can cooperatively form the quadrilateral structure. The end of the linkage rod <NUM> is pivoted to the first tubular member <NUM>, and another end of the linkage rod <NUM> is pivoted to the pivot frame <NUM> at the third pivot point. The end of the second rod <NUM> is pivoted to the third tubular member <NUM>, and another end of the second rod <NUM> is pivoted to the linkage rod <NUM> at the fourth pivot point. The second pivot point b, the third pivot point and the fourth pivot point are located at the same pivot axis, so as to make the pivot frame <NUM>, the first rod <NUM> and the second rod <NUM> cooperatively form the linkage structure. Via the design in which the linkage rod <NUM> drives the second rod <NUM> to be folded relative to the pivot frame <NUM> by the folding of the first tubular member <NUM> relative to the third tubular member <NUM>, the third tubular member <NUM> can be folded relative to the second tubular member <NUM> simultaneously, so as to achieve the purpose that the folding of the first folding tubular member <NUM> relative to the third tubular member <NUM> can drive the third tubular member <NUM> to be folded relative to the second tubular member <NUM>. In such a manner, the carrier frame <NUM> of the present invention can be released and folded synchronously and have advantages that the carrier frame <NUM> is easy to fold, has a simple structure, and is convenient to operate.

Claim 1:
A carrier frame (<NUM>) comprising:
a first tubular member (<NUM>);
a second tubular member (<NUM>) pivoted to the first tubular member (<NUM>);
a third tubular member (<NUM>) pivoted to the second tubular member (<NUM>) to form a pivot portion (<NUM>) cooperatively with the first tubular member (<NUM>) and the second tubular member (<NUM>); and
a folding unit (<NUM>) comprising:
a pivot frame (<NUM>) hinged to the pivot portion (<NUM>) and the second tubular member (<NUM>) respectively;
a first rod (<NUM>), an end of the first rod (<NUM>) being pivoted to the pivot frame (<NUM>) at a first pivot point, another end of the first rod (<NUM>) being pivoted to the pivot frame (<NUM>) at a second pivot point;
a linkage rod (<NUM>), an end of the linkage rod (<NUM>) being pivoted to the first tubular member (<NUM>), another end of the linkage rod (<NUM>) being pivoted to the pivot frame (<NUM>) at a third pivot point; and
a second rod (<NUM>), an end of the second rod (<NUM>) being pivoted to the third tubular member (<NUM>), another end of the second rod (<NUM>) being pivoted to the linkage rod (<NUM>) at a fourth pivot point, the second pivot point, the third pivot point and the fourth pivot point being located at the same pivot axis;
wherein a folding of the first tubular member (<NUM>) relative to the third tubular member (<NUM>) drives the second rod (<NUM>) via the linkage rod (<NUM>) to be folded relative to the pivot frame (<NUM>), so as to fold the third tubular member (<NUM>) relative to the second tubular member (<NUM>).