Lift gate for cargo truck

Abstract

The present invention discloses a lift gate for a cargo truck comprising: a pair of vertical masts installed on both sides of the rear end of the cargo box of the cargo truck; a pair of elevation sliders installed to be vertically movable along the pair of vertical masts and having a clevis fixed at the bottom; and a platform attached to the clevis of the pair of elevation sliders by a hinge joint, which moves cargo up and down along the pair of vertical masts to load and unload cargo into the cargo box and opens and closes outwardly downward of the cargo box around the hinge.

Description

Technology Field

[0001] The present invention relates to an electric lift gate installed at the rear of a cargo bed of a truck to easily load and unload heavy cargo in a location without a loading dock. More specifically, it relates to a lift gate for a truck designed to improve the convenience of loading and unloading operations by eliminating the inconvenience caused by contact interference during loading and unloading, and to create a quiet and comfortable working environment by minimizing operating noise and impact generated during the loading and unloading process. Background Technology

[0002] Generally, the floor of a truck's cargo bed is located about 80 to 145 cm above the ground, so the large height difference from the ground makes loading and unloading bulky and heavy cargo very difficult and inconvenient. To resolve this, a lift gate is installed and used at the bottom of the tailgate of the truck's cargo bed.

[0003] These lift gates are designed to move up and down by the operation of a lift or actuator, and are structured to be unfolded and folded parallel to the ground to push cargo transport carts (carriers), etc., backward or forward for loading and unloading.

[0004] That is, the lift gate comprises a lift body installed at the rear of the cargo compartment of a truck and a gate panel that is movable relative to the lift body and folds up or unfolds vertically around an axle pin, and normally functions as a door to open and close the rear of the cargo compartment, and performs the function of a lift when loading and unloading cargo into the cargo compartment.

[0005] For example, Patent Document 1 discloses a lift power gate for a truck, comprising a pair of lift covers (7) installed in an upright position on both sides of the rear end of a truck cargo box as illustrated in FIG. 1, a pair of lift guides (9) that move up and down along the pair of lift covers (7), a power gate (14) that can be folded and unfolded and connected to the lower part of the lift guides (9) by a hinge joint, and a cylinder (2) that pulls or releases a rope wound on a composite pulley having both a fixed pulley and a movable pulley while connected to the pair of lift guides (9), wherein the direction of pulling and releasing the rope is switched by the forward and backward movement of the cylinder (2), thereby causing the lift guides (9) and the power gate (14) to slide up and down simultaneously along the pair of lift covers (7).

[0006] However, when the power gate (14) of such a conventional lift gate is closed, a large wall surface is formed in the direction of travel of the cargo truck, so there is a problem of driving resistance that hinders the driving and driving noise such as unpleasant wind noise, as the cargo truck receives a lot of air resistance when it collides with the air while driving.

[0007] In addition, when the lift guide (9) rises along the lift cover (7) and reaches the top, it collides with the lift cover (7), causing a dull metallic noise and impact. As a result, the painted surfaces of the lift guide (9) and the lift cover (7) are easily damaged or worn out, and in severe cases, rust forms, resulting in an unsightly appearance.

[0008] Meanwhile, Patent Document 2 discloses a lift gate for a special vehicle having a structure that can be folded and unfolded by connecting the first and second lift panels with a hinge member.

[0009] This prevents collisions when the first and second lift panels of the lift gate are folded and closed in alignment with the columns installed on both rear sides of the cargo compartment, and prevents the second lift panel, which is located inside the cargo compartment and has a width narrower than the gap between the left and right columns, from moving freely in the forward direction when the vehicle is driven in that state, by installing a stopper protruding from the inner surface of the column.

[0010] However, due to the nature of this type of two-stage folding lift gate, where the stopper protrudes from the column into the inside of the cargo box and is fixed, it causes contact interference during the loading and unloading of cargo. This affects the loading and unloading of cargo, causing significant inconvenience, and also reduces the loading and working space of the cargo box, resulting in very poor loading and unloading convenience.

[0011] In addition, there is a problem that cargo, such as expensive products and equipment, may be damaged if it hits the stopper due to carelessness during the process of loading and unloading cargo in the cargo compartment.

[0012] It is stated that the background technology or prior art described above is information possessed by the inventor of the present invention or acquired during the process of deriving and completing the present invention, and is specified merely to aid in understanding the technical significance of the present invention and to be useful for prior art search and examination; furthermore, drawing symbols in the prior art are mutually unrelated to the drawing symbols in the present invention. Prior art literature

[0013] KR 10-1639550 B1 2016. 07. 07.KR 10-2043131 B1 2019. 11. 05.KR 10-1804446 B1 2017. 11. 28.KR 10-2318944 B1 2021. 10. 22.KR 10-2300106 B1 2021. 09. 02.KR 10-2221485 B1 2021. 02. 23. The problem to be solved

[0014] Accordingly, the inventor, while comprehensively considering the aforementioned matters and aiming to resolve the technical limitations and problems of existing truck lift gates, devoted great effort to continuous research to develop a truck lift gate with a new structure capable of improving loading and unloading convenience by eliminating the inconvenience caused by contact interference during loading and unloading operations, and furthermore, creating a quiet and comfortable working environment by minimizing operating noise and impact generated during the loading and unloading process, thereby conceived this invention as a result.

[0015] Therefore, the technical problem and objective that the present invention aims to solve is to provide a lift gate for a cargo truck that prevents contact interference during the loading and unloading of cargo.

[0016] Another technical problem and objective that the present invention aims to solve is to provide a lift gate for a cargo truck that can minimize operating noise and impact generated during the loading and unloading of cargo.

[0017] The technical problems and objectives that the present invention aims to solve are not limited to those mentioned above, and other technical problems and objectives not mentioned will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0018] A specific means according to an aspect of the present invention for effectively achieving a specific technical purpose while embodying a new concept to solve the technical problem of the present invention as described above, presents a lift gate for a cargo truck comprising: a pair of vertical masts installed on both sides of the rear end of a cargo truck cargo box; a pair of elevation sliders installed to be vertically movable along the pair of vertical masts and having a clevis fixed at the bottom; and a platform attached to the clevis of the pair of elevation sliders by a hinge joint, which moves cargo up and down along the pair of vertical masts to load and unload cargo into the cargo box and opens and closes outwardly downward of the cargo box around the hinge.

[0019] In particular, the present invention provides a lift gate for a cargo truck characterized by comprising: a first platform attached to the clevis by a hinge joint; a second platform formed to be narrower than the first platform and foldably connected to the free end of the first platform; and further comprising, in order to limit the angle at which the platform turns in the closing direction to within a certain range when the first and second platforms are folded and stacked and rotated around the first pintle to close the rear of the cargo box, a first swivel stopper formed protruding from the surface of the first platform opposite to the elevation slider and in contact with the surface of the elevation slider; an elevation stopper formed protruding from one side of the elevation slider so as not to protrude into the inner surface of the vertical mast; and a second swivel stopper formed protruding from both sides of the second platform and in contact with the elevation stopper.

[0020] Thus, the present invention prevents collisions when the elevation stopper and the swivel stopper come into contact when the platform is folded and raised to close the rear of the cargo box, and additionally, when the platform is locked with a locking device while closed, the elevation stopper and the swivel stopper maintain a stable contact state, thereby preventing the second platform located inside the cargo box from moving freely forward or shaking due to its own weight while the vehicle is driving.

[0021] In addition, as a preferred aspect of the present invention, a pair of elevation sliders may be supported by a rope wound around a composite pulley combining several fixed pulleys and movable pulleys, and may be applied by adopting a structure that changes the direction of the force acting on the rope by changing the position of the movable pulley axis, which moves according to the extension and contraction of the actuator, to pull up or lower.

[0022] Additionally, in a preferred aspect of the present invention, the platform comprises: an arm fixed to both sides of the first platform and connected to the clevis by a first pintle; a knuckle mounted between the free end of the first platform and the second platform so that the second platform is folded and overlapped or unfolded horizontally with respect to the first platform, having a first pin hole formed on one side for connecting the free end of the first platform with a second pintle and a second pin hole formed on the opposite side for connecting the end of the second platform with a third pintle; a first knuckle stopper mounted on the lower surface of the first platform; and a knuckle mounted on the upper surface of the second platform, wherein the knuckle rotates 90 degrees in the unfolding direction of the second platform around the second pintle, and contacts the first knuckle stopper when the second platform rotates 90 degrees in the unfolding direction around the third pintle. It may be configured to include a second knuckle stopper that maintains the first platform and the second platform in a state where they are spread horizontally apart from each other.

[0023] Thus, the present invention can stably maintain the first platform and the second platform in a horizontally unfolded state, thereby increasing work safety during cargo loading and unloading, and can minimize volume by folding them flat and stacked when the vehicle is in motion.

[0024] In addition, a preferred aspect of the present invention is configured to further include a buffer stopper that is mounted at the position where the elevation slider is raised to its highest point among the upper parts of the pair of vertical masts and absorbs and disperses the impact generated when the elevation slider is raised and collides, thereby minimizing the operating noise and impact force of the elevation slider during the loading and unloading process, and creating a quiet and comfortable working environment. Effects of the invention

[0025] According to an embodiment that implements the technical concept on which a unique solution means is based to solve the technical problem of the present invention, when the platform is folded and raised to close the rear of the cargo box, the elevation stopper and the second swivel stopper come into contact simultaneously to prevent a strong collision, and additionally, when the platform is locked with a locking device while closed, the state in which the elevation stopper and the second swivel stopper come into contact is stably maintained, so that the second platform located inside the cargo box can be prevented from moving freely or shaking in the forward direction due to its own weight when the vehicle is driven.

[0026] Therefore, unlike conventional methods, there is no need to mount a stopper to prevent movement of the second platform by protruding it into the inside of the cargo box, thereby eliminating the inconvenience caused by contact interference during loading and unloading operations of cargo, and thus improving loading and unloading convenience and transportation efficiency. In addition, by stably fixing the platform to the vertical mast, the vehicle can move without unstable movement or noise during driving, thereby increasing the driving safety of the vehicle.

[0027] In addition, when the elevation slider rises to the top, the buffer stopper absorbs and disperses the impact, minimizing operating noise and shock during cargo loading and unloading, thereby creating a quiet and comfortable working environment. Furthermore, it prevents rust from forming as the paint on the surfaces of the elevation slider and buffer stopper peels off or is damaged due to frequent impacts between the elevation slider and the buffer stopper.

[0028] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0029] FIG. 1 is an exploded perspective view illustrating an exemplary conventional lift gate for a cargo truck. FIG. 2 is a perspective view showing a state in which a platform is laid down to open the rear of a cargo box while a lift gate for a cargo truck according to an embodiment of the present invention is installed in the cargo box of a cargo truck. FIG. 3 is a perspective view showing some of the main elements constituting a lift gate for a cargo truck according to an embodiment of the present invention. FIG. 4 is a perspective view showing the elevation slider and platform among the main elements constituting a lift gate for a cargo truck according to an embodiment of the present invention. FIG. 5 is a perspective view showing the platform in an unfolded state, which is one of the main elements constituting a lift gate for a cargo truck according to an embodiment of the present invention. Figure 6 is a cross-sectional view of Figure 5. FIG. 7 is a perspective view showing the platform folded and set up to close the rear of the cargo box while the lift gate for a cargo truck according to an embodiment of the present invention is installed in the cargo box of the cargo truck. FIG. 8 is a plan cross-sectional view of a key part showing the state in which a platform is folded and erected to close the rear of a cargo box while a lift gate for a cargo truck according to an embodiment of the present invention is installed in the cargo box of a cargo truck. FIG. 9 is a perspective view of the main parts showing the state in which the platform is folded and erected to close the rear of the cargo box while the lift gate for a cargo truck according to an embodiment of the present invention is installed in the cargo box of the cargo truck. FIG. 10 is a perspective view showing a buffer stopper disassembled from the main elements constituting a lift gate for a cargo truck according to an embodiment of the present invention. FIG. 11 is a cross-sectional view showing a buffer stopper, which is one of the main elements constituting a lift gate for a cargo truck according to an embodiment of the present invention. Specific details for implementing the invention

[0030] Hereinafter, an embodiment according to the present invention will be described in more detail with reference to the attached drawings.

[0031] Prior to this, it is specified that the terms described below are defined in consideration of their functions in the present invention, and that they should be interpreted in accordance with the concept consistent with the technical concept of the present invention and the meaning commonly accepted or recognized in the relevant technical field.

[0032] In addition, if it is determined that a detailed description of known functions or configurations related to the present invention could obscure the essence of the present invention, such detailed description is omitted.

[0033] It is stated that the drawings attached herein may be partially exaggerated or simplified for the purpose of explaining the configuration and operation of the technology, as well as for ease of understanding and clarity, and that each component in the drawings does not exactly correspond to the actual size and shape.

[0034] In addition, the term "and / or" in this specification means a combination of multiple related described items or includes any of the multiple related described items, and when a part is said to include a certain component, it means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0035] In other words, terms such as "comprising" or "having" as set forth in this specification mean that there is an existence of a feature, number, step, operation, component, part, or combination thereof, and should be understood as not excluding the existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0036] In addition, the terms "part" and "unit" refer to a unit or module form that performs a role in processing at least one intended function or a certain operation within the system, and this can be implemented through means such as hardware, software, or a combination of hardware and software, or as a device or assembly capable of performing independent operations.

[0037] Furthermore, terms such as top, bottom, upper surface, lower surface, or upper, lower, upper side, lower side, front / rear, left / right, etc. used in this invention are used for convenience to distinguish relative positions or explain directions of movement for each component. For example, the upper part on the drawing may be named or referred to as the upper part and the lower part as the lower part, and the length direction may be named or referred to as the front / rear direction and the width direction as the left / right direction.

[0038] In addition, the terms "first," "second," etc. used in this invention may be used to describe various components. That is, the terms "first," "second," etc. may be used solely for the purpose of distinguishing one component from another.

[0039] [Best form for implementing the invention]

[0040] As illustrated in FIGS. 2 to 9, the lift gate for a cargo truck according to an embodiment of the present invention is installed at the rear of the cargo box (B) to operate in lifting and tilting by the action of a hydraulic or pneumatic system for loading and unloading cargo on the cargo box (B) of the cargo truck, and the main elements constituting the above mainly include a vertical mast (10), an elevation slider (20), and a platform (30).

[0041] vertical mast (10) It is constructed with a two-stage extendable structure to vertically raise or lower cargo in the cargo compartment (B) and is installed on both sides of the rear end of the cargo compartment (B).

[0042] And the vertical mast (10) is made up of a left and right pair, and each has a guide rail (11) formed thereon to guide the smooth lifting of the elevation slider (20).

[0043] That is, the vertical mast (10) is formed in the shape of a vertically elongated rectangular tube made of a hollow metal material, and a pull-out rail frame (12) is inserted therein to guide and stably support the lifting of the elevation slider (20) and to perform lifting operations using a guide roller (13).

[0044] And the rail frame (12) is formed in the shape of a vertically elongated rectangular tube made of metal material with a hollow interior, similar to the vertical mast (10), and a guide rail (11) is formed to guide the smooth lifting of the elevation slider (20).

[0045] Here, the rail frame (12) is in contact with the top of the elevation slider (20) so that it can move up and down according to the elevation of the elevation slider (20), and also moves smoothly and seamlessly along the inner surface of the vertical mast (10) by the guide roller (13), thereby inducing stable and accurate elevation operation of the elevation slider (20).

[0046] Elevation slider (20) It is installed to be able to move up and down along the vertical mast (10) using power.

[0047] That is, the elevation sliders (20) are formed as a pair on the left and right sides and are symmetrically installed on both the left and right sides of the platform (30) to apply a uniform load to the platform (30).

[0048] And the elevation slider (20) is formed in a shape resembling the letter T, with a cross-sectional shape viewed from above having a horizontal section and a vertical section, and on both the upper and lower sides of the vertical section that is inserted into the rail frame (12) through the guide rail (11) of the vertical mast (10), a lifting roller (23) is installed to allow it to move smoothly and seamlessly along the rail frame (12) while inserted into the rail frame (12) of the vertical mast (10).

[0049] In addition, a hanger (24) is installed in the center of the vertical section of the elevation slider (20) to hang and connect a wire for raising and lowering the elevation slider (20).

[0050] And the horizontal portion of the elevation slider (20) is installed so as to be exposed to the outside of the surface of the vertical mast (10), and a clevis (21) for attaching a platform (30) by a hinge joint is fixed to the lower part of the horizontal portion.

[0051] In addition, an elevation stopper (22) is formed protruding from one side of the horizontal portion of the elevation slider (20) so as not to protrude into the inner surface of the vertical mast (10).

[0052] Here, the lifting device for raising and lowering the elevation slider (20) in the vertical direction can be applied by adopting a conventional hydraulic structure that is supported by a wire wound around a composite pulley combining several fixed pulleys and movable pulleys, and by changing the direction of the force acting on the wire by the positional movement of the movable pulley axis that moves according to the extension and contraction of an actuator operated by fluid pressure, thereby raising or lowering it.

[0053] In addition, to distribute the tension applied to the wire, reduce the load burden, extend the service life, and maintain stable balance during the lifting and lowering of the platform (30), it is preferable to have the wire formed as a pair at the front and back or installed in double.

[0054] Platform (30) It is formed in the shape of a plate having a certain width and width to place cargo on.

[0055] And the platform (30) is attached to the clevis (21) of a pair of elevation sliders (20) by a hinge joint, and is designed to open and close to the outside and below of the cargo box (B) around the hinge.

[0056] In addition, the platform (30) is installed to allow cargo to be moved up and down along a pair of vertical masts (10) for loading and unloading cargo into the cargo box (B).

[0057] And a specific example of the platform (30) is configured to include the first platform (31) and the second platform (32).

[0058] 1st platform (31)It is formed with a width wider than the gap between a pair of left and right vertical masts (10) and is attached to the clevis (21) of the elevation slider (20) by a hinge joint.

[0059] That is, the first platform (31) is installed to rotate around the first pintle (33) so as to be folded vertically with respect to the vertical mast (10) or laid flat horizontally.

[0060] And on the side of the two edge surfaces of the first platform (31) that faces the elevation slider (20), a first swivel stopper (34) is formed protrudingly so as to come into contact with the surface of the elevation slider (20) when the platform (30) is folded and set up to close the rear of the cargo box (B), as shown in FIGS. 8 and 9.

[0061] In addition, load-supporting arms (36) are fixed to both sides of the first platform (31).

[0062] And at the end of the arm (36), a clevis eye (not shown) is formed to connect with the clevis (21) of the elevation slider (20) via a pin joint.

[0063] In addition, an angle adjustment pin (36a) is mounted on the surface facing the lower surface of the elevation slider (20) of the arm (36) to freely adjust the unfolding angle of the first platform (31) by adjusting the protrusion height using a screw tightening method to change the contact angle.

[0064] Here, the first swivel stopper (34) is preferably formed from an elastic material such as synthetic rubber, silicone, or synthetic resin, which has excellent weather resistance, flexibility, wear resistance, and impact resistance, and is flexible and elastically deformed when subjected to external force, thereby absorbing and mitigating shock.

[0065] 2nd platform (32)The spacing between the left and right pair of vertical masts (10) and the width of the left and right sides are formed to be relatively narrower than that of the first platform (31), and are connected and installed to the free end of the first platform (31) in a foldable manner.

[0066] That is, the second platform (32) is mounted so as to be folded and stacked or unfolded horizontally at the free end of the first platform (31).

[0067] And on both sides of the second platform (32), as shown in FIGS. 8 and 9, a second swivel stopper (35) is formed protruding and comes into contact with the elevation stopper (22) when the platform (30) is folded and erected to close the rear of the cargo box (B).

[0068] That is, when the first and second platforms (31)(32) are folded and stacked and rotated around the first pintle (33) to close the rear of the cargo box (B), the first swivel stopper (34) and the second swivel stopper (35) come into contact with the surface of the elevation slider (20) or the elevation stopper (22), thereby limiting the angle at which the platform (30) turns in the closing direction to within a certain range.

[0069] And a knuckle (37) is mounted between the free end of the first platform (31) and the second platform (32) so that the second platform (32) can be folded and stacked or spread out horizontally with respect to the first platform (31).

[0070] Additionally, on one side of the knuckle (37), a first pin hole (37a) is formed to connect the free end of the first platform (31) to the second pintle (38a) and to allow relative rotation with the second pintle (38a) as an axis, and on the opposite side, a second pin hole (37b) is formed to connect the end of the second platform (32) to the third pintle (38b) and to allow relative rotation with the third pintle (38b) as an axis.

[0071] And a first knuckle stopper (41) is mounted on the lower surface of the free end of the first platform (31), and a second knuckle stopper (42) is mounted on the upper surface of the second platform (32).

[0072] That is, when the knuckle (37) rotates 90 degrees in the unfolding direction of the second platform (32) around the second pintle (38a) and the second platform (32) rotates 90 degrees in the unfolding direction around the third pintle (38b), the first knuckle stopper (41) and the second knuckle stopper (42) come into contact, so that the first platform (31) and the second platform (32) can maintain a state in which they are spread horizontally relative to each other.

[0073] And at the front of the second platform (32), a loading ramp (39) is attached at an angle to maintain a stable contact state without a step difference with the ground and to guide the wheels of a cargo transport cart to roll smoothly.

[0074] Here, the platform (30) may be formed by connecting several hollow plates or panels formed by extruding aluminum alloy or the like into a predetermined cross-sectional shape having a thickness that ensures bending rigidity and strength.

[0075] In addition, it is preferable that the upper surface of the platform (30) has a number of anti-slip protrusions formed at regular intervals in the width direction to prevent cargo or cargo transport carts from sliding.

[0076] [Operating Principle and Function]

[0077] The main operation, operating principle, and function of the lift gate for a cargo truck according to the embodiment of the present invention configured as described above are as follows.

[0078] First, as shown in FIGS. 8 and 9, when the platform (10) is folded and erected to close the rear of the cargo box (B), the first and second swivel stoppers (34) (35) come into contact with the exposed surface of the elevation slider (20) or the elevation stopper (22) at the same time, preventing a strong collision from occurring.

[0079] In addition, when the platform (30) is closed and locked with the locking device (L), the elevation stopper (22) and the second swivel stopper (35) are stably maintained in contact, so the second platform (32) located inside the cargo box (B) can be prevented from moving freely forward or shaking due to its own weight while the vehicle is driving.

[0080] Therefore, there is no need to install a separate structure that protrudes into the inside of the cargo box (B), which can improve loading and unloading convenience and transportation efficiency by eliminating the inconvenience caused by contact interference during loading and unloading operations of cargo.

[0081] In addition, the platform (30) is stably fixed to the vertical mast (10) so that it can move without unstable movement or noise while the vehicle is driving, thereby increasing the driving safety of the vehicle.

[0082] [Other forms for implementing the invention]

[0083] Meanwhile, as illustrated in FIG. 2, the lift gate for a cargo truck according to an embodiment of the present invention includes a buff stopper (50) to absorb and disperse the impact generated when the elevation slider (20) rises and collides.

[0084] That is, the buff stopper (50) is mounted so that its lower surface is positioned at the location where the elevation slider (20) rises to its highest point among the upper parts of a pair of vertical masts (10).

[0085] Here, the buff stopper (50) can be formed by covering or attaching an elastic material such as synthetic rubber, silicone, or synthetic resin, which has excellent weather resistance, flexibility, wear resistance, and impact resistance, while being flexible and elastically deformed by external force only on the lower part that contacts the upper surface of the elevation slider (20).

[0086] For example, the buff stopper (50) is configured to include a metal support plate (51) fixedly installed on the rear of the vertical mast (10) as shown in FIGS. 10 and 11, and a protective cap (54) made of an elastic material that is detachably attached to the bottom of the support plate (51) and has a cushioning effect.

[0087] And at the lower part of the support plate (51), a press-fit part (52) is formed integrally and protrudes to be joined to the protective cap (54) in a press-fit manner to prevent the protective cap (54) from easily moving or coming off by external force.

[0088] Additionally, an insertion part (53) is formed protruding from the rear surface of the support plate (51) to be inserted into the guide rail (11) of the vertical mast (10) to maintain a secure fixed state.

[0089] That is, the support plate (51) is fixed to the rear of the vertical mast (10) to stably support the mounting state of the protective cap (54).

[0090] Here, the support plate (51) can be fixed to the rear of the vertical mast (10) by joining methods such as welding, bolting, or riveting.

[0091] In addition, the protective cap (54) can be joined to the press-fit part (52) by an over-fit method or securely joined using a male and female groove and a hook to prevent it from easily coming off when subjected to external force.

[0092] These buff stoppers (50) can create a quiet and comfortable working environment by minimizing the operating noise and impact force of the elevation slider (20) that occurs during the process of loading and unloading cargo into the cargo box (B).

[0093] In addition, it is possible to prevent rust from forming as the paint on the surface peels off or is damaged due to frequent impact between the elevation slider (20) and the buff stopper (50).

[0094] Meanwhile, it is obvious to those skilled in the art that the present invention is not limited by the embodiments described above and the attached drawings, and that it can be modified and applied in various ways not exemplified within the scope of the technical concept of the present invention, as well as widely applied by substituting each component and changing to equivalent alternative embodiments.

[0095] Therefore, content related to modifying and applying the technical features of the present invention should be interpreted as being included within the technical concept and scope of the present invention. Explanation of the symbols

[0096] 10: Vertical mast 11: Guide rail 12: Rail frame 13: Guide roller 20: Elevation Slider 21: Clevis 22: Elevation Stopper 23: Lifting Roller 30: Platform 31: First Platform 32: Platform 2 33: Pintle 1 34: 1st swivel stopper 35: 2nd swivel stopper 36: Arm 37: Knuckle 37a: 1st pin hole 37b: 2nd pin hole 38a: Second pintle 38b: Third pintle 39: Loading ramp 41: 1st knuckle stopper 42: 2nd knuckle stopper 50: Buffer stopper

Claims

Claim 1 A pair of vertical masts installed on both sides of the rear end of a cargo bed and extending in multiple stages; a pair of elevation sliders installed to be vertically movable along the pair of vertical masts and having a clevis fixed at the bottom; a platform attached by a hinge joint to the clevis of the pair of elevation sliders, which moves cargo up and down along the pair of vertical masts to load and unload cargo into the cargo bed and opens and closes outwardly downward around the hinge; wherein the platform comprises a first platform attached by a hinge joint to the clevis; A lift gate for a cargo truck, comprising: a second platform formed to be narrower than the first platform and foldably connected to the free end of the first platform; wherein, in order to limit the angle at which the platform rotates in the closing direction to within a certain range when the first and second platforms are folded and stacked and rotate around the first pintle to close the rear of the cargo box, a first swivel stopper formed protruding from the surface of the first platform opposite to the elevation slider and in contact with the surface of the elevation slider; an elevation stopper formed on the elevation slider so as not to protrude into the inner surface of the vertical mast; and a second swivel stopper formed protruding from both sides of the second platform and in contact with the elevation stopper. Claim 2 In claim 1, the pair of elevation sliders are supported by a rope wound around a composite pulley combining several fixed pulleys and movable pulleys, and are pulled up or down by changing the direction of the force acting on the rope through the positional movement of the movable pulley axis, which moves according to the extension and contraction of the actuator; the elevation stopper is formed protruding from one side of the elevation slider; the platform is fixed to both sides of the first platform and is connected to the clevis and the first pintle; the arm is mounted between the free end of the first platform and the second platform so that the second platform is folded and overlapped with respect to the first platform or unfolded horizontally with respect to the ground, and the knuckle has a first pin hole formed on one side for connecting the free end of the first platform to the second pintle and a second pin hole formed on the opposite side for connecting the end of the second platform to the third pintle; and on the lower surface of the first platform A lift gate for a cargo truck, comprising: a first knuckle stopper mounted thereon; and a second knuckle stopper mounted on the upper surface of the second platform, wherein the knuckle rotates 90 degrees in the unfolding direction of the second platform around the second pintle, and contacts the first knuckle stopper when the second platform rotates 90 degrees in the unfolding direction around the third pintle, thereby maintaining the first platform and the second platform in a state of being spread horizontally apart from each other.

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