Window sealing test system

Abstract

The application provides a kind of car window tightness test system, and relates to the technical field of tightness detection.The car window tightness test system comprises: a box, the top of the box is provided as an opening, the end of the opening is in a plane and is provided with a sealing ring, the sealing ring protrudes from the end of the opening by a predetermined height; a pressing device, the pressing device is arranged above the box, for pressing the component to be tested on the sealing ring of the opening of the box, so that the component to be tested forms a sealed space with the box; a driving device, the driving device is arranged on the side wall of the box, the driving end of the driving device is connected with the pressing device, for driving the pressing device to press the component to be tested on the opening; a gas charging device, one end of the gas charging device is connected with a gas source and the other end communicates with the inside of the box, the gas charging device is provided with a pressure gauge, and the gas charging device is used to apply a gas with a predetermined pressure to the sealed space.The car window tightness test system can realize the detection of the tightness of the train window.

Description

Technical Field

[0001] The present invention relates to the technical field of sealing detection, and in particular to a vehicle window sealing test system. Background Art

[0002] With the development of rail vehicle technology, the speed of trains is constantly increasing. High-speed trains can now reach speeds of more than 300km / h, bringing great convenience to people's travel.

[0003] However, when a train enters a tunnel, a compression wave is generated in front of the train, propagating toward the exit at the speed of sound. Upon reaching the tunnel exit, the compression wave propagates in the opposite direction as an expansion wave. As the rear of the train enters the tunnel, another expansion wave is generated at the tunnel entrance, propagating along the tunnel toward the exit at the speed of sound. Upon reaching the tunnel exit, it propagates in the opposite direction as a compression wave. When the compression wave generated by the front of the train enters the tunnel, the expansion wave reflected back from the exit and the expansion wave generated by the rear of the train meet at the train's location, creating a superposition effect. This creates a maximum negative pressure in the annular space outside the train. When the reflected compression waves meet at the train's location, the annular space reaches maximum positive pressure. Pressure fluctuations within the tunnel are transmitted through gaps in the train body, impacting the driver and passengers' eardrums, causing symptoms such as tinnitus and ear pain, and impacting ride comfort. Therefore, as train speeds increase, the amplitude of these pressure fluctuations increases, exacerbating adverse reactions, including nausea and vomiting in severe cases.

[0004] Therefore, the sealing performance of the train windows has a great impact on the pressure changes inside the car, so it is necessary to design a system or device that can detect the sealing performance of the windows to ensure that the windows installed on the train have good sealing performance. Summary of the Invention

[0005] In view of this, an embodiment of the present invention provides a vehicle window sealing test system. To solve the above technical problems, the present invention mainly provides the following technical solutions:

[0006] An embodiment of the present invention provides a vehicle window sealing test system, comprising:

[0007] A box body, wherein the top of the box body is set to be an opening, the end of the opening is in a plane and is provided with a sealing ring, and the sealing ring protrudes from the end of the opening by a preset height;

[0008] A pressing device, which is arranged above the box body and is used to press the component to be tested onto the sealing ring of the box body opening so that the component to be tested and the box body form a sealed space;

[0009] A driving device, the driving device is arranged on the side wall of the box body, the driving end of the driving device is connected to the pressing device, and is used to drive the pressing device to press the component to be tested onto the opening;

[0010] An inflation device, one end of which is connected to a gas source and the other end of which is connected to the interior of the box, wherein the inflation device is provided with a pressure gauge and is used to apply gas of a preset pressure to the sealed space.

[0011] Specifically, the box body is a shell structure, an edge is provided around the opening of the box body, a receiving groove is provided on the top of the edge, and a portion of the sealing ring is received in the receiving groove.

[0012] Specifically, the pressing device is a frame, the shape of which corresponds to the opening shape of the box.

[0013] Specifically, connecting parts are provided on opposite sides of the pressing device;

[0014] The driving device is arranged on two opposite sides of the box body and is movably connected to the connecting parts on both sides of the pressing device respectively.

[0015] Specifically, the connecting portion is a shaft, and the shaft is arranged parallel to the side of the holding device through a support body;

[0016] The driving end of the driving device is connected to the shaft through a hook, or the driving end of the driving device arranged on one side of the box is connected to the shaft through a hook, and the driving end of the driving device on the other side is rotatably connected to the shaft.

[0017] Specifically, the two opposite sides of the pressing device where the connecting portion is provided are respectively a first side and a second side, the number of the connecting portions provided on the first side of the pressing device is 2 or 3, and they are provided at intervals on the first side of the pressing device, and the number and distribution of the connecting portions provided on the second side of the pressing device are the same as those on the first side;

[0018] The number of the driving devices is the same as the number of the connecting parts, and the driving devices are connected to the connecting parts one by one.

[0019] Specifically, two opposite side walls of the box body are respectively connected to one side plate of the L-shaped support plate, and the driving device is installed on the other side plate of the L-shaped support plate.

[0020] Specifically, the inflation device includes a tube body, a three-way valve and a pressure stabilizing device. One end of the tube body is connected to the air source and the other end is connected to the inside of the box body. The pressure gauge, the three-way valve and the pressure stabilizing device are connected in series in the tube body in sequence.

[0021] Specifically, the vehicle window sealing test system provided by the embodiment of the present invention further includes:

[0022] A control unit is connected to the driving device and the inflation device.

[0023] Specifically, the vehicle window sealing test system provided by the embodiment of the present invention further includes:

[0024] The top of the frame is connected to the bottom of the box, and the bottom of the frame is provided with rollers.

[0025] By means of the above technical solution, the vehicle window sealing test system provided by the embodiment of the present invention has at least the following advantages:

[0026] A vehicle window sealing test system provided by an embodiment of the present invention has an open box and a holding device located above the opening. When driven by a driving device, the holding device can press the component to be tested, i.e., the part of the vehicle body frame with the window, above the opening of the box, so that the component to be tested and the box form a sealed space, i.e., simulating the sealed environment of a train. The vehicle window sealing test system provided by an embodiment of the present invention is also provided with an inflation device connected to the interior of the box, so that the inflation device can apply gas of the pressure required for testing the sealing in the sealed space. After that, the change in the pressure value of the sealed space can be recorded according to the display of the pressure gauge. Finally, the time constant method or the equivalent leakage hole area method can be used to evaluate the sealing performance of the vehicle window based on the time and pressure data obtained above. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a vehicle window sealing test system provided by an embodiment of the present invention;

[0028] Figure 2 A front view of a vehicle window sealing test system provided by an embodiment of the present invention without an inflator connected;

[0029] Figure 3 A left side view of a vehicle window sealing test system provided by an embodiment of the present invention without an inflator connected;

[0030] Figure 4 A top view of a vehicle window sealing test system provided by an embodiment of the present invention without an inflator connected;

[0031] Figure 5 A schematic diagram of the box structure of a vehicle window sealing test system provided by an embodiment of the present invention;

[0032] Figure 6 A schematic structural diagram of a pressing device of a vehicle window sealing test system provided by an embodiment of the present invention;

[0033] Figure 7 A schematic structural diagram of a driving device of a vehicle window sealing test system provided by an embodiment of the present invention;

[0034] Figure 8 A schematic structural diagram of the connection between a box and a frame of a vehicle window sealing test system provided by an embodiment of the present invention.

[0035] Figures 1 to 8 Reference numerals in the figures include:

[0036] 1-box, 11-opening, 12-edge, 121-accommodating groove, 2-sealing ring, 3-holding device, 31-connecting part, 32-support body, 4-driving device, 5-inflating device, 51-pressure gauge, 52-tube, 53-three-way valve, 54-pressure stabilizing device, 6-hook, 7-L-shaped support plate, 8-frame, 9-roller, 10-part to be tested. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] like Figure 1-Figure 7 As shown, an embodiment of the present invention provides a vehicle window sealing test system, which includes: a box body 1, the top of the box body 1 is set as an opening 11, the end of the opening 11 is in a plane and is provided with a sealing ring 2, and the sealing ring 2 protrudes from the end of the opening 11 by a preset height;

[0039] A pressing device 3 is provided above the box body 1 and is used to press the component to be tested 10 onto the sealing ring 2 of the opening 11 of the box body 1 so that the component to be tested 10 and the box body 1 form a sealed space;

[0040] A driving device 4, wherein the driving device 4 is disposed on a side wall of the box body 1, and a driving end of the driving device 4 is connected to the pressing device 3, and is used to drive the pressing device 3 to press the component to be tested 10 onto the opening 11;

[0041] An inflating device 5 , one end of which is connected to a gas source and the other end of which is connected to the interior of the box 1 , is provided with a pressure gauge 51 , and is used to apply gas of a preset pressure into the sealed space.

[0042] Specifically, for the convenience of description, the embodiments of the present invention are as follows. Figure 1As shown, the top, bottom and side edges are described correspondingly based on the normal placement state of the vehicle window sealing test system.

[0043] like Figure 1 and Figure 5 As shown, the box 1 can be manufactured by welding metal plates, and its structural dimensions can be set according to the dimensions of the vehicle window to be tested and the portion of the vehicle body frame that supports the window. For example, the box 1 can be set as a rectangular box 1, the volume can be set to 0.3 cubic meters, and the length, width and height of the inner cavity can be 1600mm, 950mm, and 200mm respectively. The above dimensions are only preferred examples and are not specific limitations on the embodiments of the present invention. In addition, in order to ensure the sealing of the box 1, the various connection points, interfaces and welds when making the box 1 can be coated with vacuum resin.

[0044] Among them, it should be noted that the end of the opening 11 of the box body 1 needs to be set on a plane, and the sealing ring 2 needs to be higher than the preset height of the end face of the opening 11 (the appropriate sealing ring 2 and sealing tape can be selected according to the needs of the test) to ensure that the component 10 to be tested can be in full contact with the opening 11 of the box body 1 around the whole circle, and a good seal can be achieved under the pressure of the holding device 3.

[0045] like Figure 1 and Figure 6 As shown, the shape of the pressing device 3 needs to be compatible with the opening 11 of the box body 1 so that appropriate pressure can be applied to the component to be tested 10 under the drive of the driving device 4. The pressing device 3 is preferably manufactured by profile welding.

[0046] like Figure 1 and Figure 7 As shown, the driving device 4 can be a device such as a pneumatic cylinder, a hydraulic cylinder, or a motor that can drive the holding device 3 to press the component 10 to be tested downward. Regardless of whether it is a pneumatic cylinder, a hydraulic cylinder, or a motor, their installation, control, and operating principles are all technologies mastered by technicians. For example, the pneumatic cylinder and the hydraulic cylinder can be connected to the holding device 3 through a hook, a ring, or other structures, while the motor can be connected to the holding device 3 through a screw and a nut. The connection between the driving device 4 and the holding device 3 can be movable or fixed, as long as it can ensure that the holding device 3 can move above the opening 11 of the box body 1 under the drive of the driving device 4. For example, it can be a reciprocating motion in the vertical direction, or it can simply apply pressure to the holding device 3 to drive the holding device 3 to move downward.

[0047] like Figure 1As shown, the inflator 5 needs to be connected to an air source and communicate with the housing 1. The connection to the housing 1 must be sealed, for example, using a quick-connect connector. A pressure gauge 51 of the inflator 5 can detect the pressure of the sealed space formed by the inflator 5 between the housing 1 and the component to be tested 10, as well as detect changes in pressure over time. The inflator 5 needs to have a pressure stabilizing function, which can be achieved by providing a pressure stabilizing device or a valve.

[0048] The vehicle window sealing test system provided in the embodiment of the present invention is used as follows:

[0049] First, lift the holding device 3 away from the opening 11 of the box body 1, or use the driving device 4 to drive the holding device 3 to the opening 11 of the box body 1; then, the body frame with the window, that is, the component to be tested 10, is buckled on the opening 11 of the box body 1, and the holding device 3 is pressed on the component to be tested 10, and the driving device 4 is used to apply pressure to the holding device 3 so that the component to be tested 10 presses the sealing ring 2 and the opening 11 of the box body 1 to completely seal, forming a sealed space; then, use the inflation device 5 to apply the pressure gas required for the test to the sealed space, monitor the change of the value of the pressure gauge 51 over time and record it; finally, the sealing performance between the glass and the window frame of the window can be judged based on the obtained data using the existing evaluation method.

[0050] A vehicle window sealing test system provided by an embodiment of the present invention has a box body 1 with an opening 11 and a holding device 3 located above the opening 11. When driven by a driving device 4, the holding device 3 can press the component to be tested 10, i.e., the part of the vehicle body frame with the window, above the opening 11 of the box body 1, so that the component to be tested 10 and the box body 1 form a sealed space, i.e., simulate the sealed environment of a train. In addition, the vehicle window sealing test system provided by an embodiment of the present invention is also provided with an inflation device 5 connected to the interior of the box body 1, so that the inflation device 5 can apply gas of the pressure required for testing the sealing in the sealed space. Afterwards, the change in the pressure value of the sealed space can be recorded according to the display of the pressure gauge 51. Finally, the time constant method or the equivalent leakage hole area method can be used to evaluate the sealing performance of the vehicle window based on the time and pressure data obtained above.

[0051] like Figure 1-Figure 3 and Figure 5 As shown, in a specific implementation, the box body 1 is a shell structure, an edge 12 is provided around the opening 11 of the box body 1, a receiving groove 121 is provided on the top of the edge 12, and a portion of the sealing ring 2 is received in the receiving groove 121.

[0052] Specifically, the box body 1 can be formed by welding plates and can have a rectangular shape. The plate at the top of the box body 1 is omitted to form the opening 11 of the box body 1. This structure facilitates the manufacture of the box body 1 and is also suitable for accommodating the component to be tested 10. However, the edge 12 of the opening 11 of the box body 1 with this structure is relatively thin. Therefore, in order to accommodate the sealing ring 2, a edge 12 can be provided around the opening 11. This can be formed by flanging the plate or by welding support strips to form the edge 12 surrounding the opening 11. It should be noted that the top of the edge 12 needs to be flush with the end of the opening 11 and located in the same plane.

[0053] At this time, a receiving groove 121 can be set at the top of the edge 12. The receiving groove 121 can be set according to the cross-sectional shape of the sealing ring 2. For example, it can be a rectangular receiving groove 121 or an arc-shaped receiving groove 121.

[0054] like Figure 6 As shown, in a specific implementation, the holding device 3 is a frame, and its shape corresponds to the shape of the opening 11 of the box body 1.

[0055] Specifically, a frame having the same shape and size as the opening 11 of the box body 1 can be formed by welding profiles such as square steel. This structure can press the component to be tested 10 onto the opening 11 of the box body 1 accordingly. When the pressing device 3 receives the driving force of the driving device 4, the pressing device 3 of the frame structure can form a corresponding extrusion structure with the opening 11 of the box body 1, thereby tightly pressing and sealing the component to be tested 10 and the opening 11.

[0056] like Figure 1-Figure 4 and Figure 6 As shown, in a specific implementation, connecting parts 31 are provided on opposite sides of the pressing device 3; the driving device 4 is provided on opposite sides of the box body 1 and is movably connected to the connecting parts 31 on both sides of the pressing device 3 respectively.

[0057] Specifically, as described above, connecting portions 31 are provided on opposite sides of the pressing device 3, and the driving device 4 is provided on opposite sides of the box body 1. This can achieve the effect of applying pressure to the opposite sides of the pressing device 3, so that the pressing device 3 is subjected to more uniform force, the force exerted on the component to be tested 10 is more uniform, and the sealing effect between the component to be tested 10 and the box body 1 is improved. At this time, the movable connection between the driving device 4 and the pressing device 3 can be a detachable connection or a rotatable connection.

[0058] In addition, connecting parts 31 can be provided on the four sides of the pressing device 3 , and the four side walls of the box body 1 are connected to the driving device 4 , so that pressure is applied to the pressing device 3 in four directions through the driving device 4 .

[0059] Furthermore, the connecting portion 31 is a shaft, and the shaft is arranged parallel to the side of the holding device 3 through a support body 32; wherein, the driving end of the driving device 4 is connected to the shaft through a hook 6, or, the driving end of the driving device 4 arranged on one side of the box body 1 is connected to the shaft through a hook 6, and the driving end of the driving device 4 on the other side is rotatably connected to the shaft.

[0060] Specifically, if Figure 6 The support body 32 shown can be a connecting claw protruding from the side of the holding device 3, and the shaft body can be inserted into the through hole of the connecting claw. The shaft body can be an axis with the same length as the side of the holding device 3, or a plurality of segmented shaft bodies can be set according to the number of driving devices 4.

[0061] When the connecting portion 31 is set as a shaft, the connection method between the driving end of the driving device 4 and the shaft is preferably the two methods described above. When the structures connecting the driving ends of the driving devices 4 on both sides of the box body 1 and the shaft are set as hooks 6, the hooks 6 and the driving ends of the driving devices 4 can be set as a rotational connection. When it is necessary to apply a holding force to the holding device 3 through the driving device 4, the hooks 6 can be hung on the shaft of the holding device 3. Conversely, when it is necessary to release the pressure applied to the holding device 3, the driving end of the driving device 4 can be extended upward, and under the action of gravity, the hooks 6 can be flipped over and separated from the shaft. When the driving end of the driving device 4 on one side of the box body 1 is connected to the shaft by a hook 6, and the other side is rotatably connected, for example, the other side is a ring sleeve rotatably connected to the shaft body, then when it is necessary to apply a holding force to the holding device 3 through the driving device 4, the hook 6 can be hung on the shaft body of the holding device 3. Conversely, when it is necessary to release the pressure applied to the holding device 3, the driving end of the driving device 4 can be extended upward, and under the action of gravity, the hook 6 can be flipped and disengaged from the shaft body. At this time, the side of the rotatable connection can make the holding device 3 rotate relative to the opening 11 of the box body 1, and then the component 10 to be tested can be buckled on the opening 11 of the box body 1 or removed from the opening 11 without removing the holding device 3.

[0062] like Figure 1-Figure 4 and Figure 6 As shown, in a specific implementation, the pressing device 3 is provided with the connecting portion 31 on opposite sides thereof, namely a first side and a second side, the number of the connecting portions 31 provided on the first side of the pressing device 3 is 2 or 3, and are provided at intervals on the first side of the pressing device 3, and the number and distribution of the connecting portions 31 provided on the second side of the pressing device 3 are the same as those on the first side; the number of the driving devices 4 is the same as the number of the connecting portions 31, and are connected to the connecting portions 31 one by one.

[0063] Specifically, the number of connecting parts 31 needs to match the number of driving devices 4 , and the number of driving devices 4 can be appropriately selected according to the need for applying pressure.

[0064] In addition, since the embodiment of the present invention requires an air source, in order to save costs, the driving device 4 can be a cylinder.

[0065] like Figure 1 、 Figure 2 and Figure 8 As shown, in a specific implementation, the two opposite side walls of the box body 1 are respectively connected to one side plate of the L-shaped support plate 7, and the driving device 4 is installed on the other side plate of the L-shaped support plate 7.

[0066] Specifically, if Figure 8 The L-shaped support plate 7 shown can be provided with reinforcing ribs to increase strength. The L-shaped support plate 7 can be connected to the box body 1 by welding, and a through hole and a threaded hole can be provided on one side plate connected to the drive device 4 to fix the drive device 4 through the threaded hole and pass the driving end of the drive device 4 through.

[0067] In a specific implementation, the inflation device 5 also includes a tube body 52, a three-way valve 53 and a pressure stabilizing device 54. One end of the tube body 52 is connected to the air source and the other end is connected to the interior of the box body 1. The pressure gauge 51, the three-way valve 53 and the pressure stabilizing device 54 are connected in series in the tube body 52 in sequence.

[0068] Specifically, the three-way valve 53 is used to apply and exhaust pressurized gas in the box body 1. The three-way valve 53 can be an electric three-way valve 53 or a manual three-way valve 53. The pressure stabilizing device 54 is capable of adjusting the required pressure value of the sealed space. When performing a sealing test, after inflation is completed, the pressure stabilizing device 54 can be used to adjust the pressure to the required value, and then the three-way valve 53 is closed. The pressure change of the sealed space is then recorded through the display of the pressure gauge 51.

[0069] In a specific implementation, the vehicle window sealing test system provided in an embodiment of the present invention further includes: a control unit (not shown in the figure), which is connected to the driving device 4 and the inflation device 5.

[0070] Specifically, the control unit may be a single chip microcomputer or a computer, etc., and a program for controlling the driving device 4 and the inflation device 5 may be pre-stored in the control unit. The control program is known to technicians.

[0071] like Figure 1-Figure 3 and Figure 8As shown, in a specific implementation, the vehicle window sealing test system provided by the embodiment of the present invention further includes: a frame 8, the top of the frame 8 is connected to the bottom of the box 1, and a roller 9 is provided at the bottom of the frame 8.

[0072] Specifically, the roller 9 can be set as a universal wheel, and a universal wheel with a brake can be selected. In this way, the arrangement of the frame 8 and the roller 9 can facilitate the movement of the vehicle window sealing test system provided by the embodiment of the present invention.

[0073] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A vehicle window sealing test system, characterized in that: It includes: A box body, wherein the top of the box body is set to be an opening, the end of the opening is in a plane and is provided with a sealing ring, and the sealing ring protrudes from the end of the opening by a preset height; A pressing device, which is arranged above the box body and is used to press the component to be tested onto the sealing ring of the box body opening so that the component to be tested and the box body form a sealed space; A driving device, the driving device is arranged on the side wall of the box body, the driving end of the driving device is connected to the pressing device, and is used to drive the pressing device to press the component to be tested onto the opening; an inflating device, one end of which is connected to a gas source and the other end of which is connected to the interior of the box, the inflating device being provided with a pressure gauge and being used to apply gas of a preset pressure into the sealed space; The box body is a shell structure, an edge is provided around the opening of the box body, a receiving groove is provided on the top of the edge, and a portion of the sealing ring is received in the receiving groove; The holding device is a frame, the shape of which corresponds to the shape of the opening of the box; Connecting portions are provided on opposite sides of the pressing device; The driving device is arranged on two opposite sides of the box body and is movably connected to the connecting parts on both sides of the holding device, and the movably connected is a detachable connection or a rotating connection; The connecting portion is a shaft, and the shaft is arranged parallel to the side of the pressing device through a support body; The driving end of the driving device is connected to the shaft body through a hook. When the driving device applies a pressing force, the hook is hooked on the shaft body of the pressing device. When the driving device releases the pressure applied to the pressing device, the driving end of the driving device extends upward to flip the hook and thereby disengage from the shaft body. Alternatively, the driving end of the driving device provided on one side of the box is connected to the shaft via a hook, and the driving end on the other side is rotatably connected to the shaft via a sleeve; When the driving device applies a pressing force to the holding device, the hook is hung on the shaft. When the driving device releases the pressure applied to the holding device, the driving device extends the driving end upward to flip the hook and disengage it from the shaft. At this time, the rotating connected side causes the holding device to rotate relative to the opening of the box, so as to facilitate the buckling of the component to be tested on the opening of the box or to remove it from the opening.

2. The vehicle window sealing test system according to claim 1, characterized in that: The two opposite sides of the pressing device where the connecting parts are arranged are respectively a first side and a second side, the number of the connecting parts arranged on the first side of the pressing device is 2 or 3, and they are arranged at intervals on the first side of the pressing device, and the number and distribution of the connecting parts arranged on the second side of the pressing device are the same as those on the first side; The number of the driving devices is the same as the number of the connecting parts, and the driving devices are connected to the connecting parts one by one.

3. The vehicle window sealing test system according to claim 1, characterized in that: Two opposite side walls of the box body are respectively connected to one side plate of the L-shaped support plate, and the driving device is installed on the other side plate of the L-shaped support plate.

4. The vehicle window sealing test system according to claim 1, characterized in that: The inflation device also includes a tube body, a three-way valve and a pressure stabilizing device. One end of the tube body is connected to the air source and the other end is connected to the inside of the box body. The pressure gauge, the three-way valve and the pressure stabilizing device are connected in series in the tube body in sequence.

5. The vehicle window sealing test system according to claim 1, characterized in that: Also includes: A control unit is connected to the driving device and the inflation device.

6. The vehicle window sealing test system according to claim 1, characterized in that: Also includes: The top of the frame is connected to the bottom of the box, and the bottom of the frame is provided with rollers.

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