Trolley with main frame and auxiliary frame convenient to unlock

Abstract

A trolley with a main frame and an auxiliary frame convenient to unlock comprises the main frame and the auxiliary frame, the main frame and the auxiliary frame have an unfolded working state and a folded working state, in the unfolded state, the main frame and the auxiliary frame are oppositely unfolded, and the trolley is in a plate trailer state; in the folding state, the auxiliary frame is folded on the main frame, and the cart is in a linear state; the cart further comprises a locking device which is arranged between the main frame and the auxiliary frame and used for locking the folded state. The locking device comprises an elastic locking piece and an auxiliary unlocking piece; the elastic locking piece comprises a limiting piece for limiting the cross rod in the positioning groove, and the auxiliary unlocking piece comprises an elastic piece acting on the cross rod, so that the cross rod keeps a movement trend of backwards popping out of the positioning groove. According to the technical scheme, when the cart is unlocked, automatic unlocking of the folded state of the cart can be achieved only by pushing the unlocking rod upwards, the step that a transverse rod is pulled away manually in the prior art is omitted, and the danger that an operator is injured in the manual pulling-away process in the prior art is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of cargo handling, and in particular to a trolley with a main frame and a sub-frame that are easy to unlock. Background Art

[0002] As a convenient and labor-saving cargo handling tool, trolleys are widely used in supermarkets, construction sites, factories, stations, airports and other occasions, which can effectively reduce the workload of porters.

[0003] At present, a multifunctional trolley is available on the market, comprising a main frame, a sub-frame and a locking device for combining the sub-frame with the main frame; when locked, the sub-frame is folded on the main frame, and when the trolley is in use, only the wheels of the main frame are in working condition; when unlocked, the main and sub-frames can be relatively unfolded, and when the trolley is in use, the wheels of the main and sub-frames are all in working condition, and the trolley can be in the form of a four-wheeled cart.

[0004] The locking device includes an elastic unlocking rod, a limiting plate, a positioning slot and a connecting rod fixedly connected to the auxiliary frame, which are positioned on the main frame. In the locked state, the connecting rod is first positioned in the positioning slot, and the positioning slot is blocked by the limiting plate to limit the connecting rod in the positioning slot. When unlocking, the unlocking rod is operated to move the limiting plate and release the blocking of the positioning slot. Then, the connecting rod is manually pulled outward to disengage the positioning slot, and then the specific deployment angle of the main and auxiliary frames is adjusted. In the process of pulling the connecting rod outward, the operator needs to hold the main frame steady with one hand and pull the connecting rod with the other hand. Because both frames are large, the operation is performed while supporting the weight of the frames, which increases the difficulty of operation. In addition, the main frame is prone to sliding back and forth during operation, and the state is unstable, which may bump against the operator.

[0005] Therefore, how to solve the above-mentioned deficiencies in the prior art has become a subject to be studied and solved by the present invention. Summary of the invention

[0006] The object of the present invention is to provide a trolley with a main frame and a sub-frame which are easy to unlock.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a handcart with a main and auxiliary frames that are easy to unlock, comprising a main frame and an auxiliary frame that are arranged in the front-to-back direction and are hinged, and the main and auxiliary frames have two working states: unfolded and folded. In the unfolded state, the two are relatively unfolded, and the main and auxiliary frames are both in working state, and the handcart is in a flatbed state; in the folded state, the auxiliary frame is folded on the main frame, the handcart is in a straight line state, and only the main frame is in working state; The cart further comprises a locking device disposed between the main and auxiliary frames for locking the closed state; The main frame comprises a main column, a sleeve hinged to the upper side of the main column, and a positioning groove provided at the lower part of the main frame and opening toward the rear; The auxiliary frame includes an auxiliary column and a crossbar fixed between the two auxiliary columns and arranged corresponding to the positioning groove; wherein the sleeve is slidably sleeved on the outer side of the auxiliary column; The locking device comprises an elastic locking member and an auxiliary unlocking member; The elastic locking member includes a limiting member for limiting the cross bar in the positioning groove, and the limiting member is connected to the main frame; The auxiliary unlocking member includes an elastic member, which acts on the cross bar to keep the cross bar in a movement tendency of popping out of the positioning groove backwards.

[0008] In the above scheme, when the cart is in the folded state, the auxiliary frame is closed on the main frame by a locking device. At this time, the cart is in a straight line state. When in use, the cart can be pushed or pulled by tilting. The cart in this state is suitable for transporting objects such as oxygen cylinders that cannot be placed horizontally but must maintain stability, or objects that are light in weight and have a short transportation distance; when the cart is in the unfolded state, the main and auxiliary frames can form a desired unfolding angle, including a four-wheel flatbed cart state. In this state, it is suitable for transporting objects with heavy weight and a short transportation distance, which can greatly reduce the labor burden of the user.

[0009] In the above scheme, when adjusting to the closed state, the sub-frame is pushed forward to make the cross bar stuck in the positioning groove, and then the cross bar is limited in the positioning groove by the limiter of the elastic locking member, so as to realize the combination of the sub-frame with the main frame. When it is necessary to adjust to the unfolded state, the unlocking rod is pushed upward, and then the limiter is driven to rotate, so that the limiter releases the limit on the cross bar, and then the cross bar pops out of the positioning groove backward under the action of the elastic member in the auxiliary unlocking member, at this time, the sub-frame is separated from the main frame, and then rotated backward and pulled upward, on the one hand, the main and sub-frames are unfolded to the corresponding angle state, and on the other hand, the height of the main frame relative to the sub-frame is adjusted, so that the cart presents a flatbed cart state or a tilted flatbed cart state, wherein the angle between the main and sub-frames is not limited to 90°, and can also be one or more other unfolding angles. Through the action of the auxiliary unlocking member, the unlocked cross bar can be ejected automatically, without manually pulling the cross bar away from the positioning groove, making the adjustment process of the unfolded state of the cart more simple and easy to operate.

[0010] In the above scheme, the cart state includes a flatbed state with a horizontal loading surface and an inclined flatbed state with an inclined loading surface. In the flatbed state, both the main and auxiliary frames are in working condition, and the gravity of the cargo and the cart is completely borne by the wheels of the main and auxiliary frames.

[0011] According to a further technical solution, the elastic locking member includes an unlocking rod and a lock seat fixedly arranged at the rear of the main frame; the limiting member is a thin limiting plate, the first end of which is fixedly connected to the unlocking rod and the second end is hinged to the lock seat; the elastic locking member also includes a first torsion spring, one end of which is positioned and connected to the lock seat and the other end is positioned and connected to the limiting plate, so that the limiting plate maintains a movement tendency toward the positioning groove. When unlocking, the unlocking rod is pushed to overcome the force of the first torsion spring, so that the unlocking rod drives the limiting plate to rotate away from the positioning groove, thereby releasing the limit on the crossbar, and the unlocking rod is released. The limiting plate rotates toward the positioning groove under the action of the first torsion spring, and the crossbar is limited in the positioning groove under the extrusion of the limiting plate, so that the auxiliary frame is locked on the main frame.

[0012] According to a further technical solution, the auxiliary unlocking member further comprises a positioning seat fixedly connected to the main frame; the elastic member comprises a thin sheet and a second torsion spring, the first end of the thin sheet is rotatably assembled in the positioning seat, the second end extends out of the positioning seat and extends into the positioning groove, when locked, the second end of the thin sheet is located at the front side of the cross bar and abuts against the cross bar; the second torsion spring is assembled in the positioning seat, and one end of the second torsion spring is positioned and connected with the positioning seat, and the other end is positioned and connected with the first end of the thin sheet, so that the second end of the thin sheet maintains a backward rotation trend. When locked, the cross bar is stuck in the positioning groove, overcomes the force of the second torsion spring and presses the thin sheet forward, when unlocked, when the limiting piece releases the limit on the cross bar, the cross bar is ejected backward from the positioning groove under the action of the second torsion spring, compared with the prior art, the cross bar is automatically ejected and separated from the positioning groove, eliminating the operator's manual pulling process of the cross bar, making the adjustment process of the unfolded state of the cart more simple and easy to operate, and also avoiding the danger of manual pulling process.

[0013] A further technical solution is that a limiting groove is provided on the limiting plate, and the limiting groove is arranged corresponding to the cross bar. Because the circumferential surface of the cross bar is a circular surface, in order to enable the limiting plate to reliably contact with the cross bar when the cross bar is squeezed forward, a limiting groove matching the outer circumference of the cross bar is opened.

[0014] According to a further technical solution, the thin sheet is S-shaped, and the surface against the cross bar is a curved surface, thereby increasing the contact surface between the thin sheet and the cross bar, so that the cross bar can be better pushed out during the backward rotation of the thin sheet.

[0015] According to a further technical solution, the lock seat is vertically fixed above the positioning seat, and the two are in an L shape, wherein the rear surface of the lock seat and the upper surface of the positioning seat together constitute the positioning groove.

[0016] A further technical solution is that the positioning groove is provided in a pair, and the two positioning grooves are respectively provided on the left and right main vehicle pillars of the main vehicle frame, and the two positioning grooves are symmetrically arranged on the left and right sides; the elastic locking member and the auxiliary unlocking member are each provided in a pair, wherein the two elastic locking members are respectively provided corresponding to the lower parts of the left and right main vehicle pillars, and the two elastic locking members are symmetrically arranged on the left and right sides; the two auxiliary unlocking members are respectively provided corresponding to the lower parts of the left and right main vehicle pillars, and the two auxiliary unlocking members are symmetrically arranged on the left and right sides. The positioning grooves, elastic locking members and auxiliary unlocking members are each provided in a pair, so that the sub-frame is more firmly locked on the main vehicle frame.

[0017] According to a further technical solution, the two unlocking rods in the two elastic locking rods extend toward each other and merge into an unlocking rod with a length in the left-right direction, and the left and right limit plates are respectively fixed at the left and right ends of the merged unlocking rod, and the merged unlocking rod is pushed upward to release the limit on both ends of the crossbar at the same time. Only one unlocking rod can drive the synchronous rotation of the two limit plates, and in the case of one-button unlocking, the synchronous unlocking of the left and right elastic locking parts is also achieved, which is simple to operate and easy to implement.

[0018] According to a further technical solution, the elastic member may also be a compression spring or a spring sheet.

[0019] The working principle and advantages of the present invention are as follows: The present invention simultaneously provides an elastic locking member and an auxiliary unlocking member on the cart. When unlocking, it is only necessary to push an unlocking rod upward to automatically unlock the closed state of the cart, thereby getting rid of the step of manually pulling away the cross bar in the prior art, and also avoiding the risk of bumping or hitting the operator in the manual pulling process in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 It is a schematic structural diagram of the main and auxiliary frames in a folded state according to an embodiment of the present invention; Attached Figure 2 For attachment Figure 1 A magnified image of point A; Attached Figure 3 It is a structural schematic diagram of the main and auxiliary frames of the embodiment of the present invention at the moment when they are unlocked from the folded state; Attached Figure 4 For attachment Figure 3 A magnified view of point B; Attached Figure 5 For attachment Figure 3 Enlarged view of point C; Attached Figure 6 An exploded view of a cart according to an embodiment of the present invention; Attached Figure 7 It is a schematic cross-sectional structure diagram of a locking device in an embodiment of the present invention combined with a vehicle pillar; Attached Figure 8It is a structural schematic diagram of the embodiment of the present invention from a rear side perspective, with the main and auxiliary frames in a folded state; Attached Fig. 9 It is a schematic structural diagram of the embodiment of the present invention from a side view, at the moment when the main and auxiliary frames are unlocked from a closed state; Attached Fig.10 It is a structural schematic diagram of the cart being unfolded into a flatbed cart from a side view of an embodiment of the present invention.

[0021] In the above drawings: 1. Main frame; 1a. Main column; 2. Sub-frame; 2a. Sub-column; 3. Sleeve; 4. Positioning groove; 5. Crossbar; 6. Limiting plate; 7. Unlocking lever; 8. Lock seat; 9. First torsion spring; 10. Positioning seat; 11. Thin plate; 12. Second torsion spring; 13. Limiting groove. Implementation

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Embodiment: The present invention will be clearly described below with diagrams and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0023] The terms used herein are only for describing specific embodiments and are not intended to be limiting of the present invention. Singular forms such as "a", "this", "here", "this" and "the" as used herein also include plural forms.

[0024] The terms “first”, “second”, etc. used in this document do not specifically refer to an order or sequence, nor are they used to limit the present case. They are only used to distinguish components or operations described with the same technical terms.

[0025] As used herein, “connected” or “positioned” may refer to two or more components or devices being in direct physical contact with each other, or being in indirect physical contact with each other, or may refer to two or more components or devices operating or moving with each other.

[0026] The words “include,” “including,” and “have” used in this document are open-ended terms, meaning including but not limited to.

[0027] The terms used in this document generally have the ordinary meaning of each term used in this field, in the context of the case and in the specific context, unless otherwise noted. Certain terms used to describe the present invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present invention.

[0028] The terms "front", "back", "up", "down", "left", "right", etc. used in this article are all directional terms. In this case, they are only used to illustrate the positional relationship between the various structures, and are not used to limit the protection plan of this case and the specific direction during actual implementation.

[0029] See attached Figure 1-10 As shown, a trolley with a main and sub-frame 2 that is easy to unlock comprises a main frame 1 and a sub-frame 2 that are arranged in the front-to-back direction and are hinged, and the main frame 1 and the sub-frame 2 have two working states, namely, unfolded and folded. In the unfolded state, the two are relatively unfolded, and the main frame 1 and the sub-frame 2 are both in working state, and the trolley is in a flatbed state or an inclined flatbed state, depending on the unfolding angles of the main frame 1 and the sub-frame 2. The figure of this case shows a flatbed state; in the folded state, the sub-frame 2 is folded on the main frame 1, the trolley is in a straight line state, and only the main frame 1 is in working state.

[0030] The main frame 1 includes a main column 1a, a sleeve 3 hinged to the upper side of the main column 1a, and a positioning groove 4 provided at the lower part of the main frame 1 and opening toward the rear; the positioning groove can be provided on the main column 1a or at other places of the main frame 1, and in this case, it is provided on the main column 1a. Preferably, a pair of positioning grooves 4 are provided, and the two positioning grooves 4 are respectively provided at the lower part of the left and right main columns 1a of the main frame 1, and the two positioning grooves 4 are provided symmetrically on the left and right.

[0031] The sub-frame 2 includes a sub-pillar 2a and a cross bar 5 fixed between the two sub-pillars 2a and arranged corresponding to the positioning groove 4; wherein the sleeve 3 is slidably sleeved on the outer side of the sub-pillar 2a; thereby realizing the rotational cooperation and sliding cooperation between the sub-frame 2 and the main frame 1.

[0032] The cart further comprises a locking device disposed between the main frame and the auxiliary frame for locking the folded state; the locking device comprises an elastic locking member and an auxiliary unlocking member.

[0033] The elastic locking member includes a limiting member that limits the cross bar 5 in the positioning groove 4, and the limiting member is connected to the main frame 1; the auxiliary unlocking member includes an elastic member that acts on the cross bar 5 to keep the cross bar 5 in a movement tendency to pop out of the positioning groove 4 backward.

[0034] The elastic locking member includes an unlocking rod 7 and a lock seat 8 fixed to the rear of the main frame 1; the limiting member is a thin limiting plate 6, the first end of which is fixedly connected to the unlocking rod 7, and the second end is hinged to the lock seat 8; the limiting plate 6 is provided with a limiting groove 13, and the limiting groove 13 is arranged corresponding to the cross bar 5. The elastic locking member also includes a first torsion spring 9, one end of which is positioned and connected to the lock seat 8, and the other end is positioned and connected to the limiting plate 6, so that the limiting plate 6 maintains a movement tendency toward the positioning groove 4.

[0035] The auxiliary unlocking member also includes a positioning seat 10 fixedly connected to the main frame 1, and the lock seat 8 is vertically fixed above the positioning seat 10, and the two are L-shaped, wherein the rear surface of the lock seat 8 and the upper surface of the positioning seat 10 together constitute the positioning groove 4. . The elastic member includes a thin sheet 11 and a second torsion spring 12, the first end of the thin sheet 11 is rotatably assembled in the positioning seat 10, and the second end extends out of the positioning seat 10 and extends into the positioning groove 4. When locked, the second end of the thin sheet 11 is located at the front side of the cross bar 5 and abuts against the cross bar 5. The thin sheet 11 is S-shaped, and the abutting surface with the cross bar 5 is a curved surface. The second torsion spring 12 is assembled in the positioning seat 10, and one end of the second torsion spring 12 is positioned and connected with the positioning seat 10, and the other end is positioned and connected with the first end of the thin sheet 11, so that the second end of the thin sheet 11 maintains a movement tendency of rotating backward. The elastic member can also be a compression spring or a spring.

[0036] In order to make the sub-frame 2 more firmly locked on the main frame 1, a pair of positioning grooves 4 are provided, and the two positioning grooves 4 are respectively provided on the left and right main pillars 1a of the main frame 1, and the two positioning grooves 4 are symmetrically arranged on the left and right sides; at the same time, a pair of elastic locking parts and auxiliary unlocking parts are provided, wherein the two elastic locking parts are respectively provided corresponding to the lower parts of the left and right main pillars 1a, and the two elastic locking parts are symmetrically arranged on the left and right sides; the two auxiliary unlocking parts are respectively provided corresponding to the lower parts of the left and right main pillars 1a, and the two auxiliary unlocking parts are symmetrically arranged on the left and right sides. For the convenience of operation, the two unlocking rods 7 in the two elastic locking rods extend toward each other and merge into an unlocking rod 7 with a length in the left and right directions, and the left and right limiting plates 6 are respectively fixed on the left and right ends of the merged unlocking rod 7, and the merged unlocking rod 7 is pushed upward to realize the simultaneous release of the limit on both ends of the cross bar 5.

[0037] According to the above structural composition, the specific working principle of the present invention is described as follows: To change the cart from the expanded state to the folded state: First, overcome the force of the first torsion spring 9 and push the unlocking lever 7 upward, so that the unlocking lever 7 drives the two left and right limiting plates 6 to rotate upward, exposing the complete positioning groove 4, and then push the sub-frame 2 toward the main frame 1, so that the cross bar 5 on the sub-frame 2 is stuck forward into the positioning groove 4, and then release the unlocking lever 7, so that the limiting plate 6 rotates downward and toward the positioning groove 4 under the action of the first torsion spring 9. During the rotation process, the limiting plate 6 squeezes the cross bar 5 and moves toward the positioning groove 4. During the displacement process, the cross bar 5 squeezes the thin plate 11 located in the positioning groove 4 forward (inward), so that the thin plate 11 overcomes the force of the second torsion spring 12 and rotates forward, thereby limiting the cross bar 5 in the positioning groove 4, and finally locking the sub-frame 2 on the main frame 1.

[0038] To change the cart from the folded state to the unfolded state: First, overcome the force of the first torsion spring 9 and push the unlocking rod 7 upward, so that the unlocking rod 7 drives the two left and right limiting plates 6 to rotate upward, exposing the complete positioning groove 4, and releasing the limit on the cross bar 5. Then the thin plate 11 rotates backward (outward) under the action of the second torsion spring 12. During the rotation, the cross bar 5 located in the positioning groove 4 is forced to be ejected backward (outward) and disengaged from the positioning groove 4, thereby unlocking the closed state. Then, the sub-frame 2 is rotated backward and then pulled upward to adjust the sub-frame 2 to the required position, and the adjusted sub-frame 2 is locked to the main frame 1 by screws, thereby finally realizing the adjustment of the unfolded state of the main and sub-frames.

[0039] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A trolley with a main frame and a sub-frame that are easy to unlock, characterized in that: The vehicle comprises a main frame (1) and a sub-frame (2) which are arranged in the front-to-back direction and are hingedly connected, and the main and sub-frames have two working states: an unfolded state and a folded state. In the unfolded state, the two are unfolded relative to each other, and the main and sub-frames are both in a working state, and the cart is in a flatbed state; in the folded state, the sub-frame (2) is folded on the main frame (1), the cart is in a straight line state, and only the main frame (1) is in a working state. The cart further comprises a locking device disposed between the main and auxiliary frames for locking the closed state; The main frame (1) comprises a main column (1a), a sleeve (3) hinged to the upper side of the main column (1a), and a positioning groove (4) provided at the lower part of the main frame (1) and opening toward the rear; The auxiliary vehicle frame (2) comprises an auxiliary vehicle column (2a) and a crossbar (5) fixedly arranged between the two auxiliary vehicle columns (2a) and arranged corresponding to the positioning groove (4); wherein the sleeve (3) is slidably sleeved on the outer side of the auxiliary vehicle column (2a); The locking device comprises an elastic locking member and an auxiliary unlocking member; The elastic locking member comprises a limiting member for limiting the crossbar (5) in the positioning groove (4), and the limiting member is connected to the main frame (1); The auxiliary unlocking member comprises an elastic member, which acts on the cross bar (5) so that the cross bar (5) maintains a movement tendency to pop out of the positioning groove (4) backwards.

2. The trolley with main and auxiliary frames that are easy to unlock according to claim 1, characterized in that: The elastic locking member comprises an unlocking rod (7) and a lock seat (8) fixed to the rear part of the main frame (1); The limiting member is a thin limiting plate (6), the first end of the limiting plate (6) is fixedly connected to the unlocking rod (7), and the second end is hinged to the lock seat (8); The elastic locking member further comprises a first torsion spring (9), one end of the first torsion spring (9) being connected to the lock seat (8) in a positioning manner, and the other end of the first torsion spring (9) being connected to the limiting plate (6) in a positioning manner, thereby enabling the limiting plate (6) to maintain a movement tendency towards the positioning groove (4).

3. The trolley with main and auxiliary frames that are easy to unlock according to claim 1 or 2, characterized in that: The auxiliary unlocking member also includes a positioning seat (10) fixedly connected to the main frame (1); The elastic member comprises a thin sheet (11) and a second torsion spring (12); the first end of the thin sheet (11) is rotatably mounted in the positioning seat (10), and the second end extends out of the positioning seat (10) and into the positioning groove (4); when locked, the second end of the thin sheet (11) is located at the front side of the cross bar (5) and abuts against the cross bar (5); The second torsion spring (12) is assembled in the positioning seat (10), and one end of the second torsion spring (12) is positioned and connected to the positioning seat (10), and the other end is positioned and connected to the first end of the thin sheet (11), thereby enabling the second end of the thin sheet (11) to maintain a backward rotating movement tendency.

4. The trolley with easily unlockable main and auxiliary frames according to claim 3, characterized in that: The limiting plate (6) is provided with a limiting groove (13), and the limiting groove (13) is arranged corresponding to the cross bar (5).

5. The trolley with easily unlockable main and auxiliary frames according to claim 3, characterized in that: The thin sheet (11) is S-shaped, and the surface that abuts against the cross bar (5) is a curved surface.

6. The trolley with main and auxiliary frames that are easy to unlock according to claim 3, characterized in that: The lock seat (8) is vertically fixed above the positioning seat (10), and the two are in an L shape, wherein the rear surface of the lock seat and the upper surface of the positioning seat together form the positioning groove (4).

7. The trolley with easily unlockable main and auxiliary frames according to claim 6, characterized in that: A pair of positioning grooves (4) are provided, the two positioning grooves (4) are respectively provided on the left and right main vehicle pillars (1a) of the main vehicle frame (1), and the two positioning grooves (4) are symmetrically arranged on the left and right sides; The elastic locking member and the auxiliary unlocking member are each provided in pair, wherein the two elastic locking members are respectively arranged corresponding to the lower parts of the left and right main vehicle pillars (1a), and the two elastic locking members are arranged symmetrically on the left and right sides; The two auxiliary unlocking components are respectively arranged corresponding to the lower parts of the left and right main vehicle pillars (1a), and the two auxiliary unlocking components are symmetrically arranged on the left and right sides.

8. The trolley with easily unlockable main and auxiliary frames according to claim 7, characterized in that: The two unlocking rods (7) in the two elastic locking rods extend toward each other and merge into an unlocking rod (7) having a length in the left-right direction. The left and right limiting plates (6) are respectively fixed to the left and right ends of the merged unlocking rod (7). The merged unlocking rod (7) is pushed upwards to simultaneously release the limits on the two ends of the cross bar (5).

9. The trolley with easily unlockable main and auxiliary frames according to claim 8, characterized in that: The elastic member may also be a compression spring or a spring sheet.

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