Foldable light box with foldable spreader bar

Abstract

A foldable light box with a collapsible spreader bar, comprising a pair of horizontal side frames (1) and a pair of vertical side frames (2), wherein the two ends of one horizontal side frame (1) are connected to the upper ends of the two vertical side frames (2) by an upper corner connector (3), and the two ends of the other horizontal side frame (1) are connected to the lower ends of the two vertical side frames (2) by a lower corner connector (4), wherein the vertical side frames (2) comprise two vertical side segments (21) and a vertical connector (22) connected between the two vertical side segments (21), characterized in that it further comprises a central seat (5) arranged between the two vertical side frames (2),wherein a spreader bar (6) is mounted between a vertical connecting piece (22) in the middle of the vertical side frame (2) and the central seat (5), wherein the inner end of the spreader bar (6) corresponding to the vertical connecting piece (22) is connected to the central seat (5) by a collapsible structure, the collapsible structure allowing the movement of the spreader bar (6) between the folded and unfolded positions and capable of locking the spreader bar (6) in the unfolded position, wherein the vertical connecting piece (22) and the outer end of the spreader bar (6) are releasably and firmly connected in the unfolded position on the side on which it is located.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of exhibition frames, in particular to a foldable light box with a collapsible spreader bar. STATE OF THE ART

[0002] Foldable light boxes are widely used for product displays, brand promotions, and more. For foldable light boxes, foldability is a crucial aspect in their design and use. This foldability significantly reduces the volume of the light box and makes it easy to carry and transport, which is especially important for application scenarios that require frequent changes of display location or outdoor activities.

[0003] The structure of the existing foldable light box is mainly composed of a foldable frame and a support rod group inside the frame, and the on-site personnel can assemble and disassemble the frame quickly and without tools, and the support rod group adopts a plug-in connection structure between the support rods, so when assembling on site, it is necessary to connect the support rods in a certain order and step by step, and even screws may be used for fixing, resulting in a complicated assembly and disassembly process, and the support rods are also prone to structural instability due to poor plug-in connection. CONTENT OF THE PRESENT UTILITY MODELS

[0004] The technical problem to be solved by the present utility model is to provide a foldable light box with a collapsible spreader bar to solve the problem of the prior art of adopting a plug-in connection structure between the support bars of the support bar group, which results in a complicated assembly and disassembly process, and the support bars are also prone to structural instability due to poor plug-in connection.

[0005] The technical solution adopted by this utility model to solve its technical problems is a foldable light box with a collapsible spreader bar, comprising a pair of horizontal side frames and a pair of vertical side frames, the two ends of one horizontal side frame being connected to the upper ends of the two vertical side frames by an upper corner connector, the two ends of the other horizontal side frame being connected to the lower ends of the two vertical side frames by a lower corner connector, the vertical side frames comprising two vertical side segments and a vertical connector connected between the two vertical side segments, and further comprising a central seat arranged between the two vertical side frames.wherein a spreader bar is mounted accordingly between a vertical connecting piece in the middle of the vertical side frame and the central seat;,

[0006] Wherein the inner end of the spreader bar corresponding to the vertical connecting piece is connected to the central seat by a foldable structure, the foldable structure allows movement of the spreader bar between the folded and unfolded positions and can lock the spreader bar in the unfolded position, wherein the vertical connecting piece and the outer end of the spreader bar are detachably fixedly connected in the unfolded position on the side on which it is located.

[0007] Preferably, the horizontal side frame comprises two horizontal side segments and a horizontal connecting piece connected between the two horizontal side segments, wherein a spreader bar is provided between the horizontal connecting piece and the center seat in the middle of the horizontal side frame;

[0008] The inner end of the spreader bar corresponding to the horizontal connecting piece is connected to the central seat by a foldable structure, the horizontal connecting piece and the outer end of the spreader bar being detachably and firmly connected in the unfolded position on the side on which it is located.

[0009] Preferably, the spreader bar corresponds to the collapsible structure individually; Wherein the detachable structure comprises an inner terminal and an outer terminal arranged on one side of the center seat, the inner terminal is elastically connected to a locking projection, the inner end of the spreader bar is fixedly connected to the inner terminal, the outer terminal has a locking hole that mates with the locking projection;

[0010] Wherein the inner terminal is movably connected to the outer terminal to allow movement of the horizontal spreader bar between the folded and unfolded positions, the spreader bar being locked in the unfolded position when the locking projection is resiliently engaged in the locking hole.

[0011] Preferably, a bushing mated with the inner terminal is provided in the outer terminal, the inner terminal being slidably mounted in the bushing along the longitudinal direction of the spreader bar, a sliding slot being opened on one or both sides of the bushing along the sliding direction of the spreader bar, a sliding column mated with the sliding slot protruding from the outer wall of the inner terminal, the sliding column being slidably and rotatably mounted in the sliding slot; Wherein a notch is opened at an end of the outer terminal remote from the center seat, the notch being arranged on one side of the outer terminal to receive the inner terminal of the spreader bar in the folded position, the sliding slot extending to the outside of the socket and the outer end of the sliding slot being opposite the notch; The sliding column is located inside the socket when the locking projection is elastically engaged in the locking hole.

[0012] Preferably, a locking sleeve is provided on the outer terminal, wherein the locking sleeve is fixedly connected to the outer terminal and the locking hole on the locking sleeve is opened; Wherein an elongated slot is provided which is connected to the socket and extends through the part of the outer terminal which is directly opposite the locking hole of the locking sleeve, the elongated slot extending to the notch.

[0013] Preferably, the inner terminal is a hollow structure, wherein a window extends outwardly through the inner wall of the inner terminal, a resilient cantilever is fixedly connected to one side of the window, the locking projection being provided on the outside of the free end of the cantilever.

[0014] Preferably, the upper end of the vertical side frame is hingedly connected to one end of the horizontal side frame by means of an upper corner connector, wherein the lower end of the vertical side frame is hingedly connected to one end of the horizontal side frame by means of a lower corner connector.

[0015] Preferably, two horizontal side segments of the same horizontal side frame are hingedly connected by a horizontal connecting piece.

[0016] Preferably, the vertical connecting piece of one vertical side frame is a straight connecting piece and the vertical connecting piece of the other vertical side frame is an articulated connecting piece; Where the straight connector is used to firmly connect the two vertical side segments;

[0017] The articulated connector is used to connect the two vertical side segments in an articulated manner.

[0018] Preferably, the horizontal side segment and the vertical side segment are a hollow structure;

[0019] Wherein the horizontal connector and the articulated connector both comprise a connecting seat and two movable members each articulated to the two ends of the connecting seat;

[0020] Wherein the movable elements at the two ends of the connecting seat are each inserted into the corresponding two horizontal side segments, wherein the two ends of the straight connecting piece are each inserted into the corresponding two vertical side segments, the movable elements at the two ends of the articulated connecting piece are each inserted into the corresponding two vertical side segments.

[0021] A footplate is attached to the lower surface of the horizontal side frame below, and the footplate and the horizontal side frame intersect.

[0022] The advantageous effect of the utility model is that the spreader bars on both sides are connected by the center seat in this utility model, so that the two spreader bars can be folded relative to the center seat, thus occupying a smaller space during transportation and being easy to carry, furthermore, the foldable structure can lock the spreader bar in the unfolded position to ensure the stability of the light box during use and prevent the spreader bar from accidentally collapsing or falling due to the action of external forces, furthermore, the spreader bar is always connected to the center seat, so that it can be quickly moved from the folded position to the unfolded position, which is conducive to the rapid deployment of the light box in the field and reduces installation time and difficulty.

[0023] Further features of the present application and its advantages will be clearly described by the following detailed description of the exemplary embodiments of the present application with reference to the figures. SHORT DESCRIPTION OF THE DRAWING

[0024] The utility model is described in detail below in conjunction with the figures and embodiments. Fig. 1 is a three-dimensional schematic representation of a foldable light box with a collapsible spreader bar in the utility model; Fig. Figure 2 is a longitudinal section view of the spreader bar when in the unfolded position in cooperation with the central seat; Fig. 3 is a sectional view of AA in Fig. 2; Fig. 4 is a three-dimensional schematic representation of an internal terminal; Fig. 5 is a schematic representation of the inner connector fixedly connected to an inner end of the spreader bar; Fig. 6 is a three-dimensional schematic representation of the center seat; Fig. Figure 7 is a three-dimensional schematic representation of the center seat when the locking sleeve is concealed and then the center seat engages with the inner connector; Fig. 8 is a three-dimensional schematic diagram of the horizontal side frame and the vertical side frame when folding; Fig. Figure 9 is a three-dimensional schematic representation of the spreader bar in the folded position; Fig. 10 is a three-dimensional schematic diagram of the horizontal side frame and the vertical side frame after folding.

[0025] Where: 1. Horizontal side frame, 11. Horizontal side segment, 12. Horizontal connecting piece; 2. Vertical side frame, 21. Vertical side segment, 22. Vertical connector, 22a. Straight connector, 22b. Articulated connector; 3. Upper corner connector; 4. Lower corner connector; 5. Center seat, 51. Outer terminal, 511. Bushing, 512. Sliding slot, 513. Notch, 514. Long slot, 52. Locking sleeve, 521. Locking hole; 6. Spreader bar, 61. Inner connector, 611. Sliding column, 612. Boom, 613. Locking projection. 7. Footplate. DETAILED DESCRIPTION

[0026] The utility model will now be described in more detail with reference to the figures. The figures are simplified schematic representations that only schematically depict the basic structure of the utility model, and they only show the composition as it relates to the utility model. The orientation and references (e.g., top, bottom, left, right, etc.) can only be used as an aid in describing the features in the figures. Accordingly, the following specific embodiments are not to be construed in a limiting sense, and the scope of the subject matter is limited only by the claims and their equivalents.

[0027] As in the Fig. 1 to 10, a foldable light box with a foldable spreader bar comprises a pair of horizontal side frames 1, a pair of vertical side frames 2 and a central seat 5 arranged between the two vertical side frames 2;

[0028] The two horizontal side frames 1 are of equal length and parallel to each other, the two vertical side frames 2 are of equal length and parallel to each other, the two ends of one horizontal side frame 1 are connected to the upper ends of the two vertical side frames 2 by an upper corner connector 3, the two ends of the other horizontal side frame 1 are connected to the lower ends of the two vertical side frames 2 by a lower corner connector 4, and the light source can be arranged on the two horizontal side frames 1;

[0029] Wherein the vertical side frames 2 comprise two vertical side segments 21 and a vertical connecting piece 22 which is connected between the two vertical side segments 21, in particular the two vertical side segments 21 connected by the vertical connecting piece 22 are of equal length, the upper end of the upper vertical side segment 21 is connected by means of an upper corner connecting piece 3 to one end of the upper horizontal side frame 1, the lower end of the lower vertical side segment 21 is connected by means of a lower corner connecting piece 4 to one end of the lower horizontal side frame 1; A spreader bar 6 is accordingly mounted between the vertical connecting piece 22 and the central seat 5 in the middle of the vertical side frame 2;

[0030] Wherein the inner end of the spreader bar 6, which corresponds to the vertical connecting piece 22, is connected to the central seat 5 by a foldable structure, the foldable structure allows the movement of the spreader bar 6 between the folded and the unfolded position and can lock the spreader bar 6 in the unfolded position, wherein the vertical connecting piece 22 and the outer end of the spreader bar 6 are detachably fixedly connected in the unfolded position on the side on which it is located, and to achieve the detachably fixed connection, a locking, clamping or other structure can be used between the vertical connecting piece 22 and the outer end of the spreader bar 6.

[0031] The folded position of the spreader bar 6 in this embodiment refers to a state in which the total length between the spreader bars 6 on both sides of the center seat 5 becomes shorter, that is, when the spreader bar 6 is in the unfolded position, the distance between the outer ends of the spreader bars 6 on both sides of the center seat 5 is L1, and when the spreader bar 6 is in the folded position, the distance between the outer ends of the spreader bars 6 on both sides of the center seat 5 is L2, where L1 is greater than L2;

[0032] The spreader bars on both sides 6 are connected by the center seat 5 in this embodiment, so that the two spreader bars 6 can be folded relative to the center seat 5 and thus occupy a smaller space during transportation and are easy to carry. Further, the foldable structure can lock the spreader bar 6 in the unfolded position to ensure the stability of the light box during use and prevent the spreader bar 6 from accidentally collapsing or falling due to the action of external forces. Further, the spreader bar 6 is always connected to the center seat 5 so that it can be quickly moved from the folded position to the unfolded position, which is conducive to the rapid deployment of the light box in the field and reduces installation time and difficulty.

[0033] In some examples, such as Fig. 1, the horizontal side frame 1 comprises two horizontal side segments 11 and a horizontal connecting piece 12 connected between the two horizontal side segments 11, and a spreader bar 6 is provided correspondingly between the horizontal connecting piece 12 and the center seat 5 in the center of the horizontal side frame 1; specifically, the two horizontal side segments 11 connected by the horizontal connecting piece are of equal length, and the upper end of the upper vertical side segment 21 is connected by means of an upper corner connecting piece 3 to one end of the upper horizontal side segment 11 remote from the horizontal connecting piece 12, and the lower end of the lower vertical side segment 21 is connected by means of a lower corner connecting piece 4 to one end of the lower horizontal side segment 11 remote from the horizontal connecting piece 12; The inner end of the spreader bar 6, which corresponds to the horizontal connecting piece 12, is connected to the central seat 5 by a foldable structure, the horizontal connecting piece 12 and the outer end of the spreader bar 6 being detachably and firmly connected in the unfolded position on the side on which it is located; In this embodiment, the surrounding spreader bars 6 are arranged at a distance of 90° around the center seat 5 to form a cross structure connecting a pair of horizontal side frames 1 and a pair of vertical side frames 2 as a single unit with the inner cross structure, so that the spreader bars 6 are able to disperse and withstand the external wind or pressure, etc. to which the light box is subjected, thereby improving the stability of the light box; At the same time, the spreader bar 6, which corresponds to the horizontal connecting piece 12, always remains connected to the center seat 5, so that it can be quickly moved from the folded position to the locked position, which is conducive to the rapid deployment of the light box in the field and reduces the installation time and difficulty.

[0034] In some examples, such as the Fig. 2 to 7, the spreader bar 6 corresponds to the folding structure individually; The detachable structure includes an inner terminal 61 and an outer terminal 51 arranged on one side of the center seat 5, the inner terminal 61 is elastically connected to a locking projection 613, the inner end of the spreader bar 6 is fixedly connected to the inner terminal 61, the outer terminal 51 has a locking hole 521 that fits with the locking projection 613; The inner connector 61 is movably connected to the outer connector 51 to allow movement of the horizontal spreader bar 6 between the folded and unfolded positions, the spreader bar 6 being locked in the unfolded position when the locking projection 613 is elastically engaged in the locking hole 521.

[0035] Since the inner terminal 61 is movably connected to the outer terminal 51, the inner terminal 61 can move along a fixed distance when the locking projection 613 is not clamped in the locking hole 521, and until the locking projection 613 is elastically clamped in the locking hole 521, the inner terminal 61 is fixed; when folding is required, a personnel only needs to manually press the locking projection 613 to release the locking projection 613 from the locking hole 521, and the inner terminal 61 will move along the fixed distance again, that is, at this time, the inner terminal 61 is able to move between the folded position and the unfolded position.

[0036] In some examples, such as the Fig. 2, Fig. 3 and Fig. 6, a bushing 511 mating with the inner terminal 61 is provided in the outer terminal 51, the inner terminal 61 being slidably mounted in the bushing 511 along the longitudinal direction of the spreader bar 6, a sliding slot 512 being opened on one or both sides of the bushing 511 along the sliding direction of the spreader bar 6; as shown in the Fig. 4 and Fig. 5, a sliding column 611 mating with the sliding slot 512 protrudes from the outer wall of the inner terminal 61, the sliding column 611 being slidably and rotatably mounted in the sliding slot 512, respectively; As in the Fig. 2 and Fig. 6, for example, the two sides of the bushing 511 are provided with a sliding slot 512, and the sliding column 611 is arranged in the sliding slot 512 accordingly; Wherein a notch 513 is opened at an end of the outer terminal 51 remote from the center seat 5, the notch 513 being arranged on one side of the outer terminal 51 to receive the inner terminal 61 of the spreader bar 6 in the folded position through the notch 513, the sliding slot 512 extending to the outside of the socket 511 and the outer end of the sliding slot 512 being opposite to the notch 513; Wherein the sliding column 611 is located within the bushing 511 when the locking projection 613 is elastically engaged in the locking hole 521.

[0037] By using the construction that the inner terminal 61 is accurately inserted into the socket 511 when the spreader bar 6 is in the extended position, the spreader bar 6 can only be slid in the extended position, so that the spreader bar 6 can be prevented from deviating relative to the center seat 5 in the extended position and the stability of the structure can be improved, and the spreader bar 6 can be slid outward when the locking projection 613 is pressed until it is released from the locking hole 521 and the slide column 611 moves along the slide slot 512 to the outside of the socket 511, and then the spreader bar 6 is rotated so that the inner terminal 61 of the spreader bar 6 is rotated into the inside of the notch 513, and finally the spreader bar 6 reaches the folded position.

[0038] In some examples, such as Fig. As shown in Fig. 6, the outer terminal 51 is provided with a locking sleeve 52. The locking sleeve 52 is fixedly connected to the outer terminal 51, and the locking hole 521 is opened at the locking sleeve 52. The locking sleeve 52 can improve the structural strength of the outer terminal 51 and also facilitates the formation of the locking hole 521.

[0039] As in Fig. 7, an elongated slot 514 is provided, which is connected to the socket 511 and extends through the part of the outer terminal 51 directly opposite the locking hole 521 of the locking sleeve 52, the elongated slot 514 extending to the notch 513; the locking projection 613 can reach the notch 513 along the elongated slot 514 after being released from the locking hole 521 to improve the flexibility of sliding of the inner terminal 61 and prevent jamming.

[0040] In some examples, such as Fig. 4, the inner terminal 61 is a hollow structure, a window is formed through the inner wall of the inner terminal 61 to the outside, an elastic cantilever 612 is fixedly connected to one side of the window, and the locking projection 613 is provided on the outside of the free end of the cantilever 612, thereby realizing that the inner terminal 61 is elastically connected to the locking projection 613, and the inner terminal 61 can also be elastically connected to the locking projection 613 by installing the coil spring, metal spring plate, and other elastic members.

[0041] In some examples, the upper end of the vertical side frame 2 is hinged to one end of the horizontal side frame 1 by means of an upper corner connector 3, and the lower end of the vertical side frame 2 is hinged to one end of the horizontal side frame 1 by means of a lower corner connector 4, in order to realize that the vertical side frame 2 can be rotated with respect to the horizontal side frame 1 and then folded;

[0042] The two horizontal side segments 11 of the same horizontal side frame 1 are connected in an articulated manner by a horizontal connecting piece 12; ie the horizontal side frame 1 can also be rotated and folded itself.

[0043] The vertical connecting piece 22 of one vertical side frame 2 is a straight connecting piece 22a and the vertical connecting piece 22 of the other vertical side frame 2 is an articulated connecting piece 22b;

[0044] The straight connecting piece 22a is used to firmly connect the two vertical side segments 21 to which it is connected, so that the straight connecting piece 22a can first be disassembled and then the horizontal side frame 1 and the vertical side frame 2 can be folded together, as shown in Fig. 8 shown;

[0045] The articulated connecting piece 22b is used to connect the two vertical side segments 21 in an articulated manner; ie, the horizontal side frame 1 can also be rotated and folded itself.

[0046] The horizontal side segment 11 and the vertical side segment 21 are a hollow structure;

[0047] Wherein the horizontal connecting piece 12 and the articulated connecting piece 22b both comprise a connecting seat and two movable members each articulatedly connected to the two ends of the connecting seat, wherein the connection of the outer end of the spreader bar 6 to the horizontal connecting piece 12 can prevent the two movable members at the two ends of the connecting seat from rotating, and the connection of the outer end of the spreader bar 6 to the articulated connecting piece 22b can prevent the two movable members at the two ends of the connecting seat from rotating;

[0048] Wherein, the movable elements at the two ends of the connecting seat are respectively inserted into the corresponding two horizontal side segments 11; wherein the two ends of the straight connecting piece 22a are respectively inserted into the corresponding two vertical side segments 21, the movable elements at the two ends of the articulated connecting piece 22b are respectively inserted into the corresponding two vertical side segments 21; the movable elements can also be elastically locked to the vertical side segments 21 to facilitate a quick assembly and disassembly process between the movable elements and the vertical side segments 21 and to ensure a certain degree of connection stability.

[0049] A base plate 7 is fixed to the lower surface of the underlying horizontal side frame 1. For example, both ends of the lower surface of the underlying horizontal side frame 1 are each fixed to a base plate 7. The base plate 7 may be, but is not limited to, firmly connected to the horizontal side frame 1 by means of screws, insertion, snapping, etc. The base plate 7 and the horizontal side frame 1 intersect, and preferably, the base plate 7 and the horizontal side frame 1 are perpendicular to each other. The working principle of the above-mentioned foldable light box with collapsible Spreader bar is: Folding process: As in Fig. 9, the movable members at the two ends of the straight connecting piece 22a are respectively pulled out from the vertical side segment 21, and the outer end of each of the spreader bars 6 is removed from the corresponding horizontal side frame 1 or vertical side frame 2; As in Fig. 10, the respective horizontal side segments 11 and vertical side segments 21 are then rotated and folded one after the other; As in Fig.8, when folding the spreader bar 6, first, the locking projection 613 is pressed until it is released from the locking hole 521, and then the spreader bar 6 is pushed outward until the sliding column 611 on the spreader bar 6 is moved along the sliding slot 512 to the outside of the socket 511, and then the spreader bar 6 is rotated so that the inner terminal 61 of the spreader bar 6 is located in the notch 513, and finally the spreader bar 6 reaches the folded position; Unfolding process: Rotate the inner connector 61 and then insert the inner connector 61 into the socket 511 of the outer connector 51 until the locking projection 613 is engaged with the locking hole 521 so that the spreader bar 6 is locked in the unfolded position, and connect each spreader bar 6 to the corresponding horizontal connecting piece 12 and the vertical connecting piece 22 and insert the movable elements at the two ends of the straight connecting piece 22a into the respective vertical side segments 21 to finally unfold the light box.

[0050] Based on the above ideal embodiments of the utility model as disclosure, a person skilled in the art can make various changes and modifications through the above description without deviating from the scope of the technical ideas of the utility model. The technical scope of the utility model is not limited to the content of the description, but must be determined in accordance with the scope of the patent claims.

Claims

[1] A foldable light box with a collapsible spreader bar, comprising a pair of horizontal side frames (1) and a pair of vertical side frames (2), wherein the two ends of one horizontal side frame (1) are connected to the upper ends of the two vertical side frames (2) by an upper corner connector (3), the two ends of the other horizontal side frame (1) are connected to the lower ends of the two vertical side frames (2) by a lower corner connector (4), the vertical side frames (2) comprising two vertical side segments (21) and a vertical connector (22) connected between the two vertical side segments (21), characterized byin that it further comprises a central seat (5) arranged between the two vertical side frames (2), wherein a spreader bar (6) is correspondingly mounted between a vertical connecting piece (22) in the middle of the vertical side frame (2) and the central seat (5), wherein the inner end of the spreader bar (6) corresponding to the vertical connecting piece (22) is connected to the central seat (5) by a foldable structure, the foldable structure allowing the movement of the spreader bar (6) between the folded and the unfolded position and being able to lock the spreader bar (6) in the unfolded position, wherein the vertical connecting piece (22) and the outer end of the spreader bar (6) are releasably and firmly connected in the unfolded position on the side on which it is located. [2] Foldable light box with foldable spreader bar according to claim 1, characterized byin that the horizontal side frame (1) comprises two horizontal side segments (11) and a horizontal connecting piece (12) which is connected between the two horizontal side segments (11), wherein a spreader bar (6) is provided between the horizontal connecting piece (12) and the central seat (5) in the middle of the horizontal side frame (1), wherein the inner end of the spreader bar (6), which corresponds to the horizontal connecting piece (12), is connected to the central seat (5) by a foldable structure, wherein the horizontal connecting piece (12) and the outer end of the spreader bar (6) are detachably and firmly connected in the unfolded position on the side on which it is located. [3] Foldable light box with foldable spreader bar according to claim 1 or 2, characterized byin that the spreader bar (6) individually corresponds to the foldable structure, the detachable structure comprising an inner connector (61) and an outer connector (51) arranged on one side of the central seat (5), the inner connector (61) being elastically connected to a locking projection (613), the inner end of the spreader bar (6) being fixedly connected to the inner connector (61), the outer connector (51) having a locking hole (521) which mates with the locking projection (613), the inner connector (61) being movably connected to the outer connector (51) to enable movement of the horizontal spreader bar (6) between the folded and unfolded positions, the spreader bar (6) being locked in the unfolded position when the locking projection (613) is elastically engaged in the locking hole (521). [4] Foldable light box with foldable spreader bar according to claim 3, characterized bythat a bushing (511) mating with the inner terminal (61) is provided in the outer terminal (51), wherein the inner terminal (61) is slidably mounted in the bushing (511) along the longitudinal direction of the spreader bar (6), a sliding slot (512) is opened on one or both sides of the bushing (511) along the sliding direction of the spreader bar (6), wherein a sliding column (611) mating with the sliding slot (512) protrudes from the outer wall of the inner terminal (61), the sliding column (611) is slidably and rotatably mounted in the sliding slot (512), wherein a notch (513) is opened at an end of the outer terminal (51) remote from the central seat (5), wherein the notch (513) is arranged on one side of the outer terminal (51) to receive the inner terminal (61) of the spreader bar (6) in the folded position,wherein the sliding slot (512) extends to the outside of the socket (511) and the outer end of the sliding slot (512) is opposite the notch (513), wherein the sliding column (611) is located inside the socket (511) when the locking projection (613) is elastically engaged in the locking hole (521). [5] Foldable light box with foldable spreader bar according to claim 4, characterized by that a locking sleeve (52) is provided on the outer terminal (51), wherein the locking sleeve (52) is fixedly connected to the outer terminal (51) and the locking hole (521) is open on the locking sleeve (52), wherein an elongated slot (514) is provided which is connected to the socket (511) and runs through the part of the outer terminal (51) which is directly opposite the locking hole (521) of the locking sleeve (52), wherein the elongated slot (514) extends up to the notch (513). [6] Foldable light box with foldable spreader bar according to claim 3, characterized by that the inner terminal (61) is a hollow structure, with a window extending outwardly through the inner wall of the inner terminal (61), an elastic cantilever (612) being fixedly connected to one side of the window, the locking projection (613) being provided on the outside of the free end of the cantilever (612). [7] Foldable light box with foldable spreader bar according to claim 2, characterized by that the upper end of the vertical side frame (2) is hingedly connected to one end of the horizontal side frame (1) by means of an upper corner connecting piece (3), wherein the lower end of the vertical side frame (2) is hingedly connected to one end of the horizontal side frame (1) by means of a lower corner connecting piece (4). [8] Foldable light box with foldable spreader bar according to claim 7, characterized bythat two horizontal side segments (11) of the same horizontal side frame (1) are articulated by a horizontal connecting piece (12). [9] Foldable light box with foldable spreader bar according to claim 8, characterized by that the vertical connecting piece (22) of one vertical side frame (2) is a straight connecting piece (22a) and the vertical connecting piece (22) of the other vertical side frame (2) is an articulated connecting piece (22b), wherein the straight connecting piece (22a) is used to connect firmly to the two vertical side segments (21), wherein the articulated connecting piece (22b) is used to connect articulately to the two vertical side segments (21). [10] Foldable light box with foldable spreader bar according to claim 9, characterized byin that the horizontal side segment (11) and the vertical side segment (21) are a hollow structure, wherein the horizontal connecting piece (12) and the articulated connecting piece (22b) both comprise a connecting seat and two movable elements, each of which is articulated to the two ends of the connecting seat, wherein the movable elements at the two ends of the connecting seat are respectively inserted into the corresponding two horizontal side segments (11), wherein the two ends of the straight connecting piece (22a) are respectively inserted into the corresponding two vertical side segments (21), the movable elements at the two ends of the articulated connecting piece (22b) are respectively inserted into the corresponding two vertical side segments (21).

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