A collapsible trolley

Abstract

The present invention discloses a foldable trolley, which includes a folding frame, a bottom plate and a roller assembly. The folding frame includes a left column, a right column, a force-applying cross beam, a front bottom frame, a rear bottom frame, a front surrounding frame, a rear surrounding frame, a front side link mechanism and a rear side link mechanism. When the force-applying cross beam slides downward, the force-applying cross beam drives the rear end of the front bottom frame and the front end of the rear bottom frame to descend, causing the front end of the front bottom frame and the rear end of the rear bottom frame to open, forming the bottom of the trolley. At the same time, the front side link mechanism and the rear side link mechanism are opened due to the force, forming a bracket for supporting the front surrounding frame and the rear surrounding frame, enabling the front surrounding frame and the rear surrounding frame to be stably opened. The foldable trolley provided by the present invention unfolds the front bottom frame, the rear bottom frame, the front surrounding frame, the rear surrounding frame, the front side link mechanism and the rear side link mechanism through the folding frame, so that the trolley has a large load-carrying space after unfolding, and is convenient to fold, occupies less space after folding, and is conducive to carrying for traveling.

Description

Technical Field

[0001] The present invention relates to the technical field of small carts, and in particular to a foldable small cart. Background Art

[0002] As people's quality of life continues to improve, they often need to go out for camping and vacation in their spare time after work. When doing outdoor activities, in order to more conveniently carry a large amount of activity materials, people usually choose to use a handcart for short-distance transportation. In order to facilitate storage and carrying, the existing foldable portable handcarts are generally designed to be more compact, so the portable handcart has limited space after being unfolded and has a weak carrying capacity. Summary of the invention

[0003] The purpose of the present invention is to provide a foldable trolley to solve the technical problems of the existing trolleys having limited unfolding space and weak carrying capacity.

[0004] In order to solve the above technical problems, the present invention discloses: a foldable cart, comprising a folding frame, a bottom plate and a roller assembly, wherein the folding frame comprises a left column, a right column, a force-applying crossbeam, a front bottom frame, a rear bottom frame, a front enclosure frame, a front connecting rod mechanism and a rear connecting rod mechanism; the bottom plate is laid on the front bottom frame and the rear bottom frame, and the roller assembly is arranged at the bottom of the front bottom frame and the bottom of the rear bottom frame; the left column and the right column are arranged symmetrically on the left and right; one end of the force-applying crossbeam can be slidably connected to the left column up and down, and the other end of the force-applying crossbeam can be slidably connected to the right column up and down; the front bottom frame and the rear bottom frame are symmetrically arranged front and back, The rear end of the front bottom frame is hinged to the force beam, and the front end of the rear bottom frame is hinged to the force beam; the front frame and the rear frame are symmetrically arranged front to back, the rear end of the front frame is hinged to the left pillar and the right pillar, and the front end of the rear frame is hinged to the left pillar and the right pillar; the front connecting rod mechanism is transmission-connected with the front bottom frame and the front frame, and the front connecting rod is used to open to support the front frame when the force beam slides down, and to close and fold when the force beam slides up; the rear connecting rod mechanism is transmission-connected with the rear bottom frame and the rear frame, and the rear connecting rod is used to open to support the rear frame when the force beam slides down, and to close and fold when the force beam slides up.

[0005] As an alternative embodiment, the front bottom frame and the rear bottom frame both include a bottom perimeter frame, a first connecting rod, and a second connecting rod; the first connecting rod is disposed on the left side of the bottom perimeter frame, the second connecting rod is disposed on the right side of the bottom perimeter frame, the first connecting rod and the second connecting rod are parallel to each other, one end of the first connecting rod and one end of the second connecting rod are both hinged to the force-applying cross beam, the other end of the first connecting rod and the other end of the second connecting rod are both hinged to the bottom perimeter frame, and a plurality of bottom plates are laid on the first connecting rod, the second connecting rod, and the bottom perimeter frame.

[0006] As an alternative embodiment, the front link mechanism and the rear link mechanism both include a first link assembly and a second link assembly, the first link assembly is disposed on the left side of the bottom perimeter frame, the second link assembly is disposed on the right side of the bottom perimeter frame, and the first link assembly and the second link assembly are symmetrically arranged left and right.

[0007] As an alternative embodiment, the first link assembly includes a first link, a second link, a third link, a fourth link, a fifth link, and a sixth link; one end of the first link is hinged to the middle of the left column, the other end of the first link is hinged to one end of the second link, and the other end of the second link is hinged to the bottom perimeter frame; one end of the third link is hinged to the bottom end of the left column, and the other end of the third link is hinged to the bottom perimeter frame; one end of the fourth link is hinged to the first link and the second link, and the other end of the fourth link is hinged to the rod body of the fifth link; the bottom end of the fifth link is hinged to the bottom perimeter frame, the top end of the fifth link is hinged to one end of the sixth link, and the other end of the sixth link is hinged to the front perimeter frame; the first link and the third link are parallel to each other; the left column, the second link, and the fifth link are parallel to each other; and the fourth link is parallel to the bottom perimeter frame.

[0008] As an alternative embodiment, the second link assembly includes a seventh link, an eighth link, a ninth link, a tenth link, an eleventh link and a twelfth link; one end of the seventh link is hinged to the middle of the right vertical column, the other end of the seventh link is hinged to one end of the eighth link, and the other end of the eighth link is hinged to the bottom perimeter frame; one end of the ninth link is hinged to the bottom end of the right vertical column, and the other end of the ninth link is hinged to the bottom perimeter frame; one end of the tenth link is hinged to the seventh link and the eighth link, and the other end of the tenth link is hinged to the rod body of the eleventh link; the bottom end of the eleventh link is hinged to the bottom perimeter frame, the top end of the eleventh link is hinged to one end of the twelfth link, and the other end of the twelfth link is hinged to the front perimeter frame; the seventh link is parallel to the ninth link; the right vertical column, the eighth link and the eleventh link are parallel; the tenth link is parallel to the bottom perimeter frame.

[0009] As an alternative embodiment, sliding grooves are provided on the inner sides of the left vertical column and the right vertical column, first connection pieces are provided on the inner sides of the bottoms of the left vertical column and the right vertical column, and second connection pieces are provided on the outer sides of the bottoms of the left vertical column and the right vertical column; connection parts are provided on the front and rear sides of the first connection piece and the second connection piece, and the connection parts are used for being hinged to the third link or the ninth link; the first connection piece is provided with a limiting groove communicating with the sliding groove, and sliding blocks slidably matched with the sliding groove are respectively provided at both ends of the force-applying cross beam.

[0010] As an alternative embodiment, connection frames are horizontally provided at the tops of the left vertical column and the right vertical column, and the notch of the connection frame faces downward; hinge parts extending downward are respectively provided at the connection ends of the front perimeter frame and the rear perimeter frame, and the hinge parts are hinged within the connection frame.

[0011] As an alternative embodiment, a cart-pulling mechanism is further included, and the cart-pulling mechanism includes a first optical rod, a second optical rod, a sliding seat, a pull rod and a fixed seat; the fixed seat is provided with a buckle part with an opening facing downward, and the buckle part is buckled and matched with the rod body of the pull rod; one end of the first optical rod and one end of the second optical rod are fixedly connected to the bottom of the force-applying cross beam; the other end of the first optical rod and the other end of the second optical rod are fixedly connected to the bottom of the bottom perimeter frame; the first optical rod is parallel to the second optical rod; the sliding seat is slidably matched with the first optical rod and the second optical rod; the fixed seat is fixedly connected to the first optical rod and the second optical rod, and the fixed seat is located at the bottom of the bottom perimeter frame; one end of the pull rod is rotatably hinged to the sliding seat in the vertical direction, and a cart-pulling handle is provided at the other end of the pull rod.

[0012] As an alternative embodiment, the roller assembly includes a caster and a pulley. Two of the casters are disposed at the bottom of the bottom perimeter frame of the front bottom frame; two of the pulleys are disposed at the bottom of the bottom perimeter frame of the rear bottom frame.

[0013] As an alternative embodiment, a lifting handle is provided at the top of the force application cross beam.

[0014] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0015] In the embodiments of the present invention, when the force application cross beam slides upward, the rear end of the front bottom frame and the front end of the rear bottom frame are driven by the force application cross beam to rise, causing the front end of the front bottom frame and the rear end of the rear bottom frame to approach each other, thereby realizing the bottom of the folding cart. At the same time, the front link mechanism and the rear link mechanism are closed due to the applied force and no longer support the front perimeter frame, enabling the front perimeter frame to rotate downward, thereby realizing the complete cart and reducing the occupied space of the cart. When the force application cross beam slides downward, the rear end of the front bottom frame and the front end of the rear bottom frame are driven by the force application cross beam to descend, causing the front end of the front bottom frame and the rear end of the rear bottom frame to open, forming the bottom of the cart. At the same time, the front link mechanism and the rear link mechanism are opened due to the applied force, forming a bracket for supporting the front perimeter frame and the rear perimeter frame, enabling the front perimeter frame and the rear perimeter frame to be stably opened to facilitate limiting the goods. A foldable cart provided by the present invention unfolds the front bottom frame, the rear bottom frame, the front perimeter frame, the rear perimeter frame, the front link mechanism and the rear link mechanism through a folding frame, so that the cart has a large load space after unfolding, is convenient to fold, occupies less space after folding, and is convenient to carry out for travel to carry luggage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic view of the usage state of an embodiment of the present invention;

[0017] Figure 2 is a schematic view of the folded state of an embodiment of the present invention;

[0018] Figure 3 is a schematic view of the structure of the second link assembly of an embodiment of the present invention;

[0019] Figure 4 is a schematic view of the structure of the first link assembly of an embodiment of the present invention;

[0020] Figure 5 is a schematic view of the structure of the bottom of the left column of an embodiment of the present invention;

[0021] Figure 6 is a schematic view of the connection between the right column and the front perimeter frame and the rear perimeter frame of an embodiment of the present invention;

[0022] Figure 7It is a schematic structural diagram of a cart-pulling mechanism according to an embodiment of the present invention;

[0023] In the drawings: 100 - folding frame, 110 - left vertical column, 120 - right vertical column, 121 - sliding groove, 122 - first connecting piece, 123 - second connecting piece, 124 - connecting portion, 125 - limiting groove, 126 - connecting frame, 130 - force-applying cross beam, 131 - lifting handle, 132 - slider, 140 - front bottom frame, 150 - rear bottom frame, 151 - bottom perimeter frame, 152 - first connecting rod, 153 - second connecting rod, 160 - front perimeter frame, 170 - rear perimeter frame, 171 - hinged portion, 180 - front side link mechanism, 190 - rear side link mechanism, 191 - first link assembly, 1911 - first link, 1912 - second link, 1913 - third link, 1914 - fourth link, 1915 - fifth link, 1916 - sixth link, 192 - second link assembly, 1921 - seventh link, 1922 - eighth link, 1923 - ninth link, 1924 - tenth link, 1925 - eleventh link, 1926 - twelfth link, 200 - bottom plate, 300 - roller assembly, 310 - universal wheel, 320 - pulley, 400 - cart-pulling mechanism, 410 - first optical rod, 420 - second optical rod, 430 - sliding seat, 440 - pull rod, 450 - cart-pulling handle, 460 - fixed seat. Detailed implementation mode

[0024] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features, used to distinguish and describe the features, without order or importance.

[0026] The following is combined with Figures 1 to 7, a foldable handcart according to an embodiment of the present invention is described, which includes a folding frame 100, a bottom plate 200, and a roller assembly 300. The folding frame 100 includes a left vertical column 110, a right vertical column 120, a force application cross beam 130, a front bottom frame 140, a rear bottom frame 150, a front enclosure frame 160, a rear enclosure frame 170, a front side link mechanism 180, and a rear side link mechanism 190; the bottom plate 200 is laid on the front bottom frame 140 and the rear bottom frame 150, and the roller assembly 300 is arranged at the bottom of the front bottom frame 140 and the bottom of the rear bottom frame 150; the left vertical column 110 and the right vertical column 120 are symmetrically arranged left and right; one end of the force application cross beam 130 is slidably connected to the left vertical column 110 in the up and down direction, and the other end of the force application cross beam 130 is slidably connected to the right vertical column 120 in the up and down direction; the front bottom frame 140 and the rear bottom frame 150 are symmetrically arranged front and rear, the rear end of the front bottom frame 140 is hinged to the force application cross beam 130, and the front end of the rear bottom frame 150 is hinged to the force application cross beam 130; the front enclosure frame 160 and the rear enclosure frame 170 are symmetrically arranged front and rear, the rear end of the front enclosure frame 160 is hinged to the left vertical column 110 and the right vertical column 120, and the front end of the rear enclosure frame 170 is hinged to the left vertical column 110 and the right vertical column 120; the front side link mechanism 180 is in transmission connection with the front bottom frame 140 and the front enclosure frame 160, and the front side link is used to open to support the front enclosure frame 160 when the force application cross beam 130 slides down, and to fold up when the force application cross beam 130 slides up; the rear side link mechanism 190 is in transmission connection with the rear bottom frame 150 and the rear enclosure frame 170, and the rear side link is used to open to support the rear enclosure frame 170 when the force application cross beam 130 slides down, and to fold up when the force application cross beam 130 slides up.

[0027] In an embodiment of the present invention, when the force - applying cross - beam 130 moves upward and slides, the force - applying cross - beam 130 drives the rear end of the front - side bottom frame 140 and the front end of the rear - side bottom frame 150 to rise, causing the front end of the front - side bottom frame 140 and the rear end of the rear - side bottom frame 150 to approach each other, thus realizing the folding of the bottom of the folding trolley. At the same time, the front - side link mechanism 180 and the rear - side link mechanism 190 are closed due to the applied force and no longer support the front enclosure frame 160, enabling the front enclosure frame 160 to rotate downward, thereby realizing the complete folding of the trolley and reducing the occupied space of the trolley. When the force - applying cross - beam 130 moves downward and slides, the force - applying cross - beam 130 drives the rear end of the front - side bottom frame 140 and the front end of the rear - side bottom frame 150 to descend, causing the front end of the front - side bottom frame 140 and the rear end of the rear - side bottom frame 150 to open, forming the bottom of the trolley. At the same time, the front - side link mechanism 180 and the rear - side link mechanism 190 open due to the applied force, forming a bracket for supporting the front enclosure frame 160 and the rear enclosure frame 170, enabling the front enclosure frame 160 and the rear enclosure frame 170 to be stably opened to facilitate the limiting of goods. A foldable trolley provided by the present invention unfolds the front - side bottom frame 140, the rear - side bottom frame 150, the front enclosure frame 160, the rear enclosure frame 170, the front - side link mechanism 180 and the rear - side link mechanism 190 through the folding frame 100, so that the trolley has a large loading space after unfolding, is convenient to fold, occupies less space after folding, and is conducive to carrying it out for traveling to carry luggage.

[0028] As a preferred embodiment, both the front - side bottom frame 140 and the rear - side bottom frame 150 include a bottom enclosure frame 151, a first connecting rod 152 and a second connecting rod 153; the first connecting rod 152 is arranged on the left side of the bottom enclosure frame 151, the second connecting rod 153 is arranged on the right side of the bottom enclosure frame 151, the first connecting rod 152 is parallel to the second connecting rod 153, one end of the first connecting rod 152 and one end of the second connecting rod 153 are both hinged to the force - applying cross - beam 130, the other end of the first connecting rod 152 and the other end of the second connecting rod 153 are both hinged to the bottom enclosure frame 151, and a plurality of bottom plates 200 are laid on the first connecting rod 152, the second connecting rod 153 and the bottom enclosure frame 151.

[0029] As a preferred embodiment, both the front - side link mechanism 180 and the rear - side link mechanism 190 include a first link assembly 191 and a second link assembly 192, the first link assembly 191 is arranged on the left side of the bottom enclosure frame 151, the second link assembly 192 is arranged on the right side of the bottom enclosure frame 151, and the first link assembly 191 and the second link assembly 192 are symmetrically arranged left and right.

[0030] In this embodiment, the first link assembly 191 and the second link assembly 192 are symmetrically arranged left and right, realizing the support of the front enclosure frame 160 and the rear enclosure frame 170 on both sides of the trolley, achieving force balance and improving the structural stability.

[0031] As a preferred embodiment, the first link assembly 191 includes a first link 1911, a second link 1912, a third link 1913, a fourth link 1914, a fifth link 1915 and a sixth link 1916; one end of the first link 1911 is hinged to the middle of the left column 110, the other end of the first link 1911 is hinged to one end of the second link 1912, and the other end of the second link 1912 is hinged to the bottom perimeter frame 151; one end of the third link 1913 is hinged to the bottom end of the left column 110, and the other end of the third link 1913 is hinged to the bottom perimeter frame 151; one end of the fourth link 1914 is hinged to the first link 1911 and the second link 1912, and the other end of the fourth link 1914 is hinged to the rod body of the fifth link 1915; the bottom end of the fifth link 1915 is hinged to the bottom perimeter frame 151, the top end of the fifth link 1915 is hinged to one end of the sixth link 1916, and the other end of the sixth link 1916 is hinged to the front perimeter frame 160; the first link 1911 is parallel to the third link 1913; the left column 110, the second link 1912 and the fifth link 1915 are parallel to each other; the fourth link 1914 is parallel to the bottom perimeter frame 151.

[0032] In this embodiment, the left column 110, the first link 1911, the second link 1912 and the third link 1913 form a parallelogram link mechanism, and the second link 1912, the fourth link 1914, the fifth link 1915 and the bottom perimeter frame 151 form another parallelogram link mechanism. Thus, when the force-applying cross beam 130 slides upward to drive the bottom perimeter frame 151 to close, the first link assembly 191 closes and folds, and when the force-applying cross beam 130 slides downward to open the bottom perimeter frame 151, the first link assembly 191 opens and forms multiple squares with the columns and the bottom perimeter frame 151 to support the front perimeter frame 160 and / or the rear perimeter frame 170, improving the structural stability.

[0033] As a preferred embodiment, the second link assembly 192 includes a seventh link 1921, an eighth link 1922, a ninth link 1923, a tenth link 1924, an eleventh link 1925, and a twelfth link 1926; one end of the seventh link 1921 is hinged to the middle of the right column 120, the other end of the seventh link 1921 is hinged to one end of the eighth link 1922, and the other end of the eighth link 1922 is hinged to the bottom perimeter frame 151; one end of the ninth link 1923 is hinged to the bottom end of the right column 120, and the other end of the ninth link 1923 is hinged to the bottom perimeter frame 151; one end of the tenth link 1924 is hinged to the seventh link 1921 and the eighth link 1922, and the other end of the tenth link 1924 is hinged to the rod body of the eleventh link 1925; the bottom end of the eleventh link 1925 is hinged to the bottom perimeter frame 151, the top end of the eleventh link 1925 is hinged to one end of the twelfth link 1926, and the other end of the twelfth link 1926 is hinged to the front perimeter frame 160; the seventh link 1921 is parallel to the ninth link 1923; the right column 120, the eighth link 1922, and the eleventh link 1925 are parallel; the tenth link 1924 is parallel to the bottom perimeter frame 151.

[0034] In this embodiment, the right column 120, the seventh link 1921, the eighth link 1922, and the ninth link 1923 form a parallelogram link mechanism, and the eighth link 1922, the tenth link 1924, the eleventh link 1925, and the bottom perimeter frame 151 form another parallelogram link mechanism. Thus, when the force-applying crossbeam 130 slides upward to drive the bottom perimeter frame 151 to close, the second link assembly 192 closes and folds. When the force-applying crossbeam 130 slides downward to open the bottom perimeter frame 151, the second link assembly 192 opens and forms multiple squares with the columns and the bottom perimeter frame 151 to support the front perimeter frame 160 and / or the rear perimeter frame 170, improving the structural stability.

[0035] As a preferred embodiment, sliding grooves 121 are provided on the inner sides of the left upright column 110 and the right upright column 120. First connecting pieces 122 are provided on the inner sides of the bottoms of the left upright column 110 and the right upright column 120. Second connecting pieces 123 are provided on the outer sides of the bottoms of the left upright column 110 and the right upright column 120. Connecting parts 124 are provided on the front and rear sides of the first connecting piece 122 and the second connecting piece 123. The connecting parts 124 are used for being hinged to the third connecting rod 1913 or the ninth connecting rod 1923. The first connecting piece 122 is provided with a limiting groove 125 communicating with the sliding groove 121. Sliders 132 slidably matched with the sliding groove 121 are respectively provided at both ends of the force-applying cross beam 130. In this way, the force-applying cross beam 130 can slide up and down relative to the left upright column 110 and the right upright column 120. Specifically, in the embodiment shown in Figure 5 When the slider 132 slides along the sliding groove 121 to the bottom of the left upright column 110 / right upright column 120, the slider 132 enters the limiting groove 125 until the slider 132 abuts against the bottom of the limiting groove 125, so as to limit the continuous downward sliding of the slider 132 and support the force-applying cross beam 130. In addition, when the force-applying cross beam 130 is loaded, the stress is dispersed to the left upright column 110, the right upright column 120, the front side link mechanism 180 and the rear side link mechanism 190 through multiple connection points of the first connecting piece 122 and the second connecting piece 123, effectively increasing the load-bearing capacity of the trolley. After experiments, the load-bearing capacity of the trolley in this embodiment reaches 200 kilograms, and it has good load-bearing capacity.

[0036] As a preferred embodiment, horizontally arranged connecting frames 126 are provided at the tops of the left upright column 110 and the right upright column 120. The notch of the connecting frame 126 is arranged downward. Hinge parts 171 extending downward are provided at the connecting ends of the front enclosure frame 160 and the rear enclosure frame 170. The hinge parts 171 are hinged in the connecting frame 126. Specifically, in the embodiment shown in Figure 6 By providing the hinge parts 171 extending downward on the front enclosure frame 160 / rear enclosure frame 170, the connecting ends of the front enclosure frame 160 / rear enclosure frame 170 are in an L shape. When the front enclosure frame 160 / rear enclosure frame 170 is opened, part of the top end surface of the front enclosure frame 160 / rear enclosure frame 170 abuts against the inner top surface of the connecting frame 126, increasing the force-bearing area between the front enclosure frame 160 / rear enclosure frame 170 and the connecting frame 126, which is beneficial to increasing the load-bearing capacity of the front enclosure frame 160 / rear enclosure frame 170. When it is necessary to close the front enclosure frame 160 / rear enclosure frame 170, the top end surface of the front enclosure frame 160 / rear enclosure frame 170 rotates downward around the hinge point of the hinge part 171, which can effectively ensure that the front enclosure frame 160 / rear enclosure frame 170 can be smoothly closed.

[0037] As a preferred embodiment, it further includes a cart pulling mechanism 400, and the cart pulling mechanism 400 includes a first optical rod 410, a second optical rod 420, a sliding seat 430, a pull rod 440 and a fixed seat 460; the fixed seat 460 is provided with a buckle portion with a downward opening, and the buckle portion is in buckle fit with the rod body of the pull rod 440; one end of the first optical rod 410 and one end of the second optical rod 420 are fixedly connected to the bottom of the force application cross beam; the other end of the first optical rod 410 and the other end of the second optical rod 420 are fixedly connected to the bottom of the bottom perimeter frame 151; the first optical rod 410 is parallel to the second optical rod 420; the sliding seat 430 is slidably matched with the first optical rod 410 and the second optical rod 420; the fixed seat 460 is fixedly connected to the first optical rod 410 and the second optical rod 420, and the fixed seat 460 is located at the bottom of the bottom perimeter frame 151; one end of the pull rod 440 is pivotally connected to the sliding seat 430 in a vertically rotatable manner, and the other end of the pull rod 440 is provided with a cart pulling handle 450. Specifically, in this embodiment, the front end of the cart pulling handle 450 protrudes from the bottom perimeter frame 151. When it is necessary to pull out the cart pulling handle 450, press down the cart pulling handle 450 to disengage the rod body of the pull rod 440 from the fixed seat 460, and then apply a pulling force to pull out the pull rod 440; then lift up the cart pulling handle 450 to re-engage the rod body of the pull rod 440 with the fixed seat 460, so as to pull out the cart pulling handle 450 from the bottom of the trolley and lock the pull rod 440. When it is necessary to retract the cart pulling handle 450, press down the cart pulling handle 450 to disengage the rod body of the pull rod 440 from the fixed seat 460, and then apply a pushing force to push back the pull rod 440; then lift up the cart pulling handle 450 to re-engage the rod body of the pull rod 440 with the fixed seat 460, so as to retract and store the cart pulling handle 450 from the bottom of the trolley and lock the pull rod 440. In this way, the trolley can be spliced with other trolleys, improving the usage scenarios of the trolley.

[0038] As a preferred embodiment, the roller assembly 300 includes universal wheels 310 and pulleys 320. Two of the universal wheels 310 are arranged at the bottom of the bottom perimeter frame 151 of the front bottom frame 140; two of the pulleys 320 are arranged at the bottom of the bottom perimeter frame 151 of the rear bottom frame 150. The two universal wheels 310 and the two pulleys 320 are used in cooperation, one in front and the other behind, to form the roller assembly 300, which facilitates the user to change the direction when pushing the trolley and improves the user experience.

[0039] As a preferred embodiment, a lifting handle 131 is provided at the top of the force application cross beam 130. In this way, it is convenient for the user to apply an upward lifting force to the lifting handle 131, further facilitating the user to fold the trolley.

[0040] Other components and operations of a foldable trolley according to an embodiment of the present invention are known to those of ordinary skill in the art and will not be described in detail here.

[0041] In the description of this specification, the descriptions referring to terms such as "embodiment", "example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0042] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A foldable trolley, comprising a folding frame, a bottom plate and a roller assembly, characterized in that ； The folding frame includes a left vertical column, a right vertical column, a force - applying cross beam, a front bottom frame, a rear bottom frame, a front enclosure frame, a rear enclosure frame, a front - side link mechanism, and a rear - side link mechanism; The bottom plate is laid on the front bottom frame and the rear bottom frame, and the roller assembly is arranged at the bottom of the front bottom frame and the bottom of the rear bottom frame; The left vertical column and the right vertical column are symmetrically arranged left and right; one end of the force - applying cross beam is slidably connected to the left vertical column, and the other end of the force - applying cross beam is slidably connected to the right vertical column; The front bottom frame and the rear bottom frame are symmetrically arranged front and rear. The rear end of the front bottom frame is hinged to the force - applying cross beam, and the front end of the rear bottom frame is hinged to the force - applying cross beam; The front enclosure frame and the rear enclosure frame are symmetrically arranged front and rear. The rear end of the front enclosure frame is hinged to the left vertical column and the right vertical column, and the front end of the rear enclosure frame is hinged to the left vertical column and the right vertical column; The front - side link mechanism is in transmission connection with the front bottom frame and the front enclosure frame. The front - side link is used to open to support the front enclosure frame when the force - applying cross beam slides down, and fold up when the force - applying cross beam slides up; the rear - side link mechanism is in transmission connection with the rear bottom frame and the rear enclosure frame. The rear - side link is used to open to support the rear enclosure frame when the force - applying cross beam slides down, and fold up when the force - applying cross beam slides up; Both the front bottom frame and the rear bottom frame include a bottom enclosure frame, a first connecting rod, and a second connecting rod; the first connecting rod is arranged on the left side of the bottom enclosure frame, the second connecting rod is arranged on the right side of the bottom enclosure frame, the first connecting rod and the second connecting rod are parallel to each other, one end of the first connecting rod and one end of the second connecting rod are both hinged to the force - applying cross beam, the other end of the first connecting rod and the other end of the second connecting rod are both hinged to the bottom enclosure frame, and several bottom plates are laid on the first connecting rod, the second connecting rod, and the bottom enclosure frame; Both the front - side link mechanism and the rear - side link mechanism include a first link assembly and a second link assembly. The first link assembly is arranged on the left side of the bottom enclosure frame, the second link assembly is arranged on the right side of the bottom enclosure frame, and the first link assembly and the second link assembly are symmetrically arranged left and right; The first link assembly includes a first link, a second link, a third link, a fourth link, a fifth link, and a sixth link; one end of the first link is hinged to the middle of the left vertical column, the other end of the first link is hinged to one end of the second link, and the other end of the second link is hinged to the bottom perimeter frame; one end of the third link is hinged to the bottom end of the left vertical column, and the other end of the third link is hinged to the bottom perimeter frame; one end of the fourth link is hinged to the first link and the second link, and the other end of the fourth link is hinged to the rod body of the fifth link; the bottom end of the fifth link is hinged to the bottom perimeter frame, the top end of the fifth link is hinged to one end of the sixth link, and the other end of the sixth link is hinged to the front perimeter frame; the first link is parallel to the third link; the left vertical column, the second link, and the fifth link are parallel; the fourth link is parallel to the bottom perimeter frame; The second link assembly includes a seventh link, an eighth link, a ninth link, a tenth link, an eleventh link, and a twelfth link; one end of the seventh link is hinged to the middle of the right vertical column, the other end of the seventh link is hinged to one end of the eighth link, and the other end of the eighth link is hinged to the bottom perimeter frame; one end of the ninth link is hinged to the bottom end of the right vertical column, and the other end of the ninth link is hinged to the bottom perimeter frame; one end of the tenth link is hinged to the seventh link and the eighth link, and the other end of the tenth link is hinged to the rod body of the eleventh link; the bottom end of the eleventh link is hinged to the bottom perimeter frame, the top end of the eleventh link is hinged to one end of the twelfth link, and the other end of the twelfth link is hinged to the front perimeter frame; the seventh link is parallel to the ninth link; the right vertical column, the eighth link, and the eleventh link are parallel; the tenth link is parallel to the bottom perimeter frame; Chute grooves are provided on the inner sides of both the left vertical column and the right vertical column. First connection pieces are provided on the inner sides of the bottoms of the left vertical column and the right vertical column, and second connection pieces are provided on the outer sides of the bottoms of the left vertical column and the right vertical column; connection parts are provided on both the front and rear sides of the first connection piece and the second connection piece, and the connection parts are used for being hinged to the third link or the ninth link; the first connection piece is provided with a limiting groove communicating with the chute groove, and sliding blocks slidably matched with the chute groove are respectively provided at both ends of the force-applying cross beam; Horizontal connection frames are provided at the tops of both the left vertical column and the right vertical column, and the notch of the connection frame faces downward; hinge parts extending downward are respectively provided at the connection ends of the front perimeter frame and the rear perimeter frame, and the hinge parts are hinged within the connection frame.

2. The foldable trolley according to claim 1, wherein: It further includes a cart-pulling mechanism, and the cart-pulling mechanism includes a first optical rod, a second optical rod, a sliding seat, a pull rod, and a fixed seat; the fixed seat is provided with a buckle part with an opening facing downward, and the buckle part is in buckle fit with the rod body of the pull rod; One end of the first polished rod and one end of the second polished rod are fixedly connected to the bottom of the force application cross beam; the other end of the first polished rod and the other end of the second polished rod are fixedly connected to the bottom of the bottom perimeter frame; the first polished rod is parallel to the second polished rod; The sliding seat is slidably matched with the first polished rod and the second polished rod; the fixed seat is fixedly connected to the first polished rod and the second polished rod, and the fixed seat is located at the bottom of the bottom perimeter frame; One end of the pull rod is pivotally connected to the sliding seat, and a cart handle is provided at the other end of the pull rod.

3. A foldable trolley according to claim 1, wherein: The roller assembly includes universal wheels and pulleys. Two of the universal wheels are provided at the bottom of the bottom perimeter frame of the front bottom frame; two of the pulleys are provided at the bottom of the bottom perimeter frame of the rear bottom frame.

4. A foldable trolley according to claim 1, wherein: A lifting handle is provided at the top of the force application cross beam.

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