Ventilation cabinet with window safety anti-falling function

Abstract

The utility model discloses a fume hood with a window safety anti-falling function, which relates to the technical field of fume hoods and comprises a fume hood body, a window is movably arranged on the fume hood body and connected with a synchronous traction belt driving mechanism, and safety anti-falling locking mechanisms are arranged on two sides of the window. The safety anti-falling locking mechanism comprises a limiting piece, a limiting lock head is arranged on the limiting piece in a telescopic mode, a lock groove hole matched with the limiting lock head is formed in the ventilation cabinet body, and when the synchronous traction belt driving mechanism is in a normal state, the limiting lock head retracts into the limiting piece, and the window can ascend and descend normally. When the synchronous traction belt driving mechanism loses efficacy, the limiting lock head extends out of the limiting piece and is clamped into the lock groove hole, the window stops falling and is locked, and when equipment failure occurs, the window can be rapidly locked, and the safety of personnel and articles is protected.

Description

TECHNICAL FIELD

[0001] The utility model relates to a ventilation cabinet technical field, concretely relates to a ventilation cabinet with safety anti-falling function of window. BACKGROUND

[0002] In the ventilation cabinet technical field, the ventilation cabinet is widely used in laboratories and other places, and is used for providing a safe ventilation environment for experimental operation to prevent harmful gases, dust and the like from causing harm to operating personnel.

[0003] However, the existing ventilation cabinet has obvious deficiencies in the safety protection of the window. The conventional ventilation cabinet window is usually lifted by a synchronous traction belt driving mechanism, but once the driving mechanism fails, such as the breaking of the traction belt or the failure of the driving motor, the window will suddenly fall due to the loss of effective support. The unexpected falling of the window not only may damage the ventilation cabinet itself and the experimental equipment placed therein, but more seriously, may cause physical injury to the experimental personnel operating in front of the ventilation cabinet, such as bruising the hands, feet or even the head, and poses a great threat to the safety of personnel and articles.

[0004] Therefore, it is an urgent problem in the field to develop a ventilation cabinet capable of quickly locking the window when the synchronous traction belt driving mechanism fails to avoid the falling of the window and effectively protect the safety of personnel and articles. SUMMARY

[0005] The utility model discloses a ventilation cabinet with safety anti-falling function of window, to solve the existing ventilation cabinet when synchronous traction belt driving mechanism fails, the window is easy to fall and causes a series of safety hidden troubles and equipment damage problems, through setting up safety anti-falling locking mechanism on both sides of the window, the mechanism contains the limiting piece that can retractable setting limiting lock head, cooperate the lock slot hole on the ventilation cabinet body, realize when synchronous traction belt driving mechanism normal work, the limiting lock head retracts, the window can normally lift, and when the driving mechanism fails, the limiting lock head quickly extends and clamps into the lock slot hole, and the window is locked immediately, avoiding falling. To this end, the personal safety of the experimental personnel is ensured, the experimental articles and equipment are protected from damage, the good running state of the ventilation cabinet is maintained, various risks caused by the falling of the window are reduced, and the safety, reliability and stability of the ventilation cabinet in actual use are improved.

[0006] In order to achieve the above object, the utility model discloses the following technical scheme: A fume hood with window safety anti-falling function, including fume hood cabinet, the movable window is provided with on the fume hood cabinet, the window is connected with synchronous traction belt drive mechanism, the both sides of window are provided with safety anti-falling locking mechanism, the safety anti-falling locking mechanism includes spacing piece, the telescopic locking head of spacing piece is set up, the fume hood cabinet is provided with the lock groove hole that cooperates with locking head, when synchronous traction belt drive mechanism normal state, the telescopic locking head is retracted to spacing piece, and the window can normally lift and fall, when synchronous traction belt drive mechanism fails, the telescopic locking head is stretched out and is clamped into the lock groove hole outside spacing piece, and the window stops falling and locks.

[0007] In order to further optimize the utility model, the following technical schemes can be preferred:

[0008] Preferably, the synchronous traction belt drive mechanism includes synchronous traction belt, synchronous belt pulley, counterweight box, the counterweight box is set up at the back of fume hood, the both ends of synchronous traction belt are connected spacing piece, counterweight box respectively, the synchronous belt pulley rotation is set up on the fume hood cabinet, and the synchronous traction belt is engaged with synchronous belt pulley.

[0009] Preferably, the spacing piece includes shell, the locking head rotation is set up in the shell, the locking portion of locking head is provided with the open slide groove on the shell, the synchronous belt connecting piece is liftable and is set up in the shell, one end of synchronous belt connecting piece extends out the shell and connects synchronous traction belt, the other end of synchronous belt connecting piece is provided with the pin shaft for installing locking head, the synchronous belt connecting piece is still coaxially sleeved with elastic element,

[0010] Preferably, the elastic element is spring, one end of spring is held on the shell, the other end of spring is held on synchronous belt connecting piece, when spring is in compression state, the telescopic locking head is retracted to the shell, when spring is completely released, the telescopic locking head stretches out open slide groove.

[0011] Preferably, the both sides of locking head are arc-shaped, the locking portion is the tooth structure, and the open slide groove is the ladder groove.

[0012] Preferably, the shell includes bottom plate and cover plate that are buckled to each other, the synchronous belt connecting piece is provided with the positioning head at one end of synchronous traction belt, and the fume hood cabinet is provided with the anti-falling clamping groove that cooperates with the positioning head.

[0013] Preferably, the fume hood cabinet is provided with the window spacing groove at the position corresponding to the both sides of window, and the lock groove hole is arrayed in the window spacing groove from top to bottom.

[0014] Preferably, the bottom of spacing piece is set up on the fume hood cabinet through the balance adjusting screw rod, and the connecting screw hole that cooperates with the balance adjusting screw rod is formed in the bottom of spacing piece.

[0015] The utility model discloses through a series of preferred technical scheme, greatly promoted the overall performance and security of fume hood, bring many remarkable beneficial effects.

[0016] The utility model discloses a fume hood through a series of optimization technical scheme, produced following beneficial effect:

[0017] (1) synchronous traction belt drive mechanism: synchronous pulley and synchronous traction band meshing, ensure that the window lifting transmission is accurate and stable, avoid jam, offset, guarantee smooth operation. Counterweight box balances the gravity of the window, reduces the load of traction belt and motor, reduces the wear and failure probability, prolongs the service life of the mechanism, reduces the maintenance frequency and cost.

[0018] (2) safety anti-falling locking mechanism: the unique limiting piece structure, the limiting lock head rotation is arranged in the shell, cooperates the opening slide groove, prevents accidental escape. Synchronous belt connecting piece and spring form efficient trigger mechanism, spring compression when the drive mechanism is normal, limiting lock head retracts;When failure, spring release, push the limiting lock head to extend and lock into the lock slot hole, lock the window quickly, guarantee the safety of personnel and goods.

[0019] (3) detail design: the arc design on both sides of the limiting lock head reduces the friction resistance when extending and retracting, improves the action agility. The contact area and friction force of the tooth structure locking part and the lock slot hole are increased, so that the locking is more firm. The stepped groove provides accurate guidance and positioning for the limiting lock head, ensures that the action is stable and accurate.

[0020] (4) installation and maintenance: the shell is composed of the bottom plate and the cover plate buckle, which is convenient for installation and maintenance. The positioning head of the synchronous belt connecting piece cooperates with the anti-falling locking groove of the cabinet body, preventing the limiting piece and the window from falling when the traction belt breaks, and adding safety protection.

[0021] (5) window limiting: the window limiting groove provides accurate guidance for the window lifting, ensures vertical stability, avoids shaking and offset, at the same time, makes the locking function of the safety anti-falling locking mechanism more reliable, and the window can be accurately locked when the drive mechanism fails at any height.

[0022] (6) balance adjustment: the limiting piece bottom is arranged on the cabinet body through the balance adjustment lead screw, which can conveniently adjust the height and horizontal position of the limiting piece, so that the mechanisms work better, and the overall performance stability and reliability of the fume hood are improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the three-dimensional structure schematic diagram of fume hood;

[0024] Figure 2 It is the internal mechanism schematic diagram of fume hood;

[0025] Figure 3It is a three-dimensional structure schematic diagram of the safety anti-falling locking mechanism;

[0026] Figure 4 It is a structure schematic diagram of the safety anti-falling locking mechanism in the retracted state of the limiting member;

[0027] Figure 5 It is a structure schematic diagram of the safety anti-falling locking mechanism in the extended state of the limiting member;

[0028] Figure 6 It is a locking structure schematic diagram of the safety anti-falling locking mechanism;

[0029] Figure 7 It is an explosion structure schematic diagram of the limiting member;

[0030] Figure 8 It is a three-dimensional structure schematic diagram of the base;

[0031] Figure 9 It is an internal structure schematic diagram of the limiting member in the retracted state of the limiting lock head;

[0032] Figure 10 It is an internal structure schematic diagram of the limiting member in the extended state of the limiting lock head;

[0033] 1, limiting member; 2, window; 3, synchronous traction belt; 4, synchronous pulley; 5, counterweight box; 6, fume hood cabinet; 7, lock slot hole; 8, anti-falling clamping groove.

[0034] 101, cover plate; 102, bottom plate; 103, open sliding groove; 104, limiting lock head; 105, locking part; 106, synchronous belt connecting piece; 107, balance adjusting screw; 108, positioning head; 109, pin shaft; 110, spring; 111, connecting threaded hole. DETAILED DESCRIPTION

[0035] In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0037] Embodiment 1:

[0038] As Figures 1-10 shown, a fume hood with a window safety anti-falling function, comprising a fume hood cabinet 6, a window 2 movably installed on the fume hood cabinet 6, a synchronous traction belt driving mechanism connected to the window 2, a safety anti-falling locking mechanism installed on both sides of the window, the safety anti-falling locking mechanism comprising a limiting piece 1, a limiting lock head telescopically installed on the limiting piece 1, a lock groove hole 7 designed on the fume hood cabinet to cooperate with the limiting lock head, when the synchronous traction belt driving mechanism is in a normal state, the limiting lock head is retracted into the limiting piece, and the window can be normally lifted and lowered; when the synchronous traction belt driving mechanism fails, the limiting lock head is extended out of the limiting piece and clamped into the lock groove hole 7, and the window is stopped from falling and locked.

[0039] The synchronous traction belt driving mechanism comprises a synchronous traction belt 3, a synchronous belt pulley 4, and a counterweight box 5, the counterweight box 5 is installed on the back of the fume hood, the synchronous traction belt 3 is connected to the limiting piece and the counterweight box at both ends respectively, the synchronous belt pulley is rotatably installed on the fume hood cabinet, and the synchronous traction belt is engaged with the synchronous belt pulley. In terms of the synchronous traction belt driving mechanism, the synchronous traction belt, the synchronous belt pulley, and the counterweight box arranged on the back of the fume hood are adopted, which has multiple advantages. The synchronous belt pulley is engaged with the synchronous traction belt, which ensures the transmission accuracy and stability during the lifting and lowering of the window, effectively avoids the phenomena of jamming and deviation of the window during lifting and lowering, and guarantees the smoothness of the operation of the experimental personnel. The counterweight box is arranged to balance the gravity of the window, reduce the load of the synchronous traction belt and the driving motor, reduce the probability of traction belt wear and motor failure caused by long-term uneven stress, significantly prolong the service life of the synchronous traction belt driving mechanism, and reduce the equipment maintenance frequency and cost.

[0040] As a preferred embodiment, the limiting member includes a housing, the limiting lock head 104 is rotatably installed in the housing, an opening slide groove 103 is formed on the housing corresponding to the locking part of the limiting lock head 104, a synchronous belt connecting piece 106 is liftably installed in the housing, one end of the synchronous belt connecting piece 106 extends out of the housing to connect a synchronous traction belt, the other end of the synchronous belt connecting piece is installed with a pin shaft 109 for installing the limiting lock head, a spring is coaxially sleeved on the synchronous belt connecting piece, one end of the spring 110 is supported on the housing, the other end of the spring 110 is supported on the synchronous belt connecting piece, when the spring is in a compressed state, the limiting lock head is retracted into the housing, when the spring is completely released, the limiting lock head extends out of the opening slide groove. The limiting member adopts a unique structure, the limiting lock head is rotatably arranged in the housing, cooperates with the opening slide groove, and ensures the flexible extension and retraction of the limiting lock head while preventing it from accidentally coming out. The synchronous belt connecting piece is liftably arranged, one end of which is connected with the synchronous traction belt, the other end of which is installed with the limiting lock head through the pin shaft, and a spring is coaxially sleeved thereon, forming an efficient triggering mechanism. When the synchronous traction belt driving mechanism works normally, the spring is in a compressed state, the limiting lock head is retracted into the housing, and the window is not affected during normal lifting; once the driving mechanism fails, the synchronous traction belt relaxes, the spring loses external compression, and is quickly and completely released, pushing the limiting lock head to extend out of the opening slide groove and accurately clamping into the locking slot hole, realizing the rapid locking of the window and effectively avoiding the falling of the window. This design greatly improves the response speed and reliability of the safety anti-falling locking mechanism, and provides a solid guarantee for the safety of personnel and goods.

[0041] As a preferred embodiment, the limiting lock head is arc-shaped on both sides, the locking part 105 is a tooth structure, and the opening slide groove includes an internal stepped groove; the limiting lock head is arc-shaped on both sides, the locking part adopts a tooth structure, and the opening slide groove is a stepped groove, which optimizes the locking effect. The arc-shaped sides facilitate the flexible rotation of the limiting lock head in the housing, and reduce the frictional resistance during extension and retraction, improving the agility of the action. When the tooth structure locking part cooperates with the locking slot hole, the contact area and friction force are increased, making the locking more firm and preventing the window from shaking or shifting in the locked state. The stepped groove design provides precise guidance and positioning for the limiting lock head, ensuring its stability and accuracy during extension and retraction.

[0042] As a preferred embodiment, the shell comprises a bottom plate 102 and a cover plate 101 which are buckled to each other, a positioning head 108 is installed at one end of the synchronous traction belt connected by a synchronous belt connector, and a falling prevention slot 8 which cooperates with the positioning head is installed on the fume hood cabinet. The shell is composed of the buckled bottom plate and cover plate, which is convenient for installation and maintenance. The positioning head is arranged at one end of the synchronous traction belt connected by the synchronous belt connector, and cooperates with the falling prevention slot on the fume hood cabinet, which further enhances the safety of the whole mechanism. Even in the extreme case of accidental breakage of the synchronous traction belt, the cooperation of the positioning head and the falling prevention slot can prevent the falling of the limiting piece and the window, and adds an additional guarantee for personnel and equipment safety.

[0043] As a preferred embodiment, a window limiting slot is installed on the fume hood cabinet corresponding to the position of the two sides of the window, and the lock slot holes are arrayed from top to bottom in the window limiting slot. The window limiting slot is arranged on the fume hood cabinet corresponding to the position of the two sides of the window, and the lock slot holes 7 are arrayed from top to bottom in the window limiting slot. This design not only provides precise guidance for the lifting of the window, ensures that the window always remains vertical and stable during lifting, and avoids shaking and deviation, but also makes the locking function of the safety anti-falling locking mechanism more reliable. No matter what height the window is at, once the synchronous traction belt driving mechanism fails, the limiting lock head can accurately enter the lock slot hole of the corresponding height to realize the locking of the window.

[0044] As a preferred embodiment, the limiting piece 1 is installed on the fume hood cabinet through a balance adjusting screw rod 107, and a connecting thread hole 111 which cooperates with the balance adjusting screw rod is arranged at the bottom of the limiting piece. The suspension level of the window can be adjusted by the balance adjusting screw rod. The limiting piece is arranged on the fume hood cabinet through the balance adjusting screw rod, and the connecting thread hole is arranged at the bottom of the limiting piece. This design facilitates the fine adjustment of the height and horizontal position of the limiting piece. During installation or use, the position of the limiting piece can be easily adjusted by rotating the balance adjusting screw rod according to actual needs, so that the safety anti-falling locking mechanism, the window and the synchronous traction belt driving mechanism work better together, and the stability and reliability of the overall performance of the fume hood are further improved.

[0045] In summary, the synergistic effect of a series of preferred technical solutions has achieved remarkable results in ensuring personnel safety, protecting experimental objects and equipment, improving equipment operation stability and reducing maintenance costs, and has high practical value and market prospect.

[0046] Based on the above embodiment, the specific debugging process of the device is as follows:

[0047] I. Component installation

[0048] ① Synchronous traction belt driving mechanism installation:

[0049] First, install the synchronous pulley at a suitable position on the fume hood cabinet, ensuring that it rotates smoothly and that the shaft is securely connected to the cabinet structure. Generally, choose the top of the cabinet or other convenient transmission positions, and fix the synchronous pulley mounting seat by bolts or welding.

[0050] Install the counterweight box at the pre-designed mounting point on the back of the fume hood. Usually, use screws to fix the counterweight box to the cabinet frame to ensure its stability and prevent it from shaking during use.

[0051] Connect one end of the synchronous traction belt to the limiting piece, which can be connected by bolts or special connecting clips to ensure firm connection. Then, wrap the synchronous traction belt around the synchronous pulley to ensure full engagement. Finally, connect the other end of the synchronous traction belt to the counterweight box, adjust the tension of the synchronous traction belt to ensure that it does not become loose or too tight during transmission.

[0052] ②: Safety anti-falling locking mechanism installation

[0053] Assemble the limiting piece and install the limiting lock head in the shell through the pin shaft to ensure that the limiting lock head can rotate freely in the shell. Then, install the synchronous belt connecting piece in the shell so that it can freely ascend and descend in the shell. Coaxially install the spring on the synchronous belt connecting piece, with one end of the spring held at the bottom of the shell and the other end held on the synchronous belt connecting piece. At this time, the spring is in a compressed state, and the limiting lock head is retracted into the shell.

[0054] Install the shell of the limiting piece on both sides of the window, which can be fixed by screws or buckles to ensure that the limiting piece is tightly connected to the window and the position is accurate. At the same time, connect the end of the synchronous belt connecting piece extending out of the shell to the synchronous traction belt to ensure reliable connection.

[0055] Install the window limiting slot on the fume hood cabinet corresponding to the position of the window on both sides. The window limiting slot and the window slide together to provide guidance for the window's ascent and descent. In the window limiting slot, array the lock slot holes from top to bottom according to the design requirements to ensure that the lock slot holes accurately correspond to the position of the limiting lock head.

[0056] Duck the bottom plate and cover plate of the shell together and tighten them with screws to complete the assembly of the limiting piece. Install the positioning head on one end of the synchronous belt connecting piece connected to the synchronous traction belt, and process the anti-falling card slot on the fume hood cabinet corresponding to the position of the positioning head to further enhance safety.

[0057] ③: Balance adjustment screw installation

[0058] A connecting threaded hole matched with the balance adjusting screw rod is formed in the bottom of the limiting member, the balance adjusting screw rod is screwed into the threaded hole in the bottom of the limiting member, and then the other end of the balance adjusting screw rod is installed in the mounting seat previously arranged on the fume hood cabinet and fastened through a nut or other fixing device to ensure that the balance adjusting screw rod can work stably and realize fine adjustment of the height and horizontal position of the limiting member.

[0059] II. Debugging process

[0060] ① Debugging of synchronous traction belt driving mechanism

[0061] Start the motor of the synchronous traction belt driving mechanism, observe the rotation of the synchronous pulley, and ensure that the synchronous pulley rotates smoothly without jamming or abnormal noise. Check the meshing condition of the synchronous traction belt and the synchronous pulley, and if necessary, adjust the position of the synchronous pulley or the tension of the synchronous traction belt to ensure that the synchronous traction belt and the synchronous pulley always maintain good meshing state.

[0062] Observe whether the window rises and falls smoothly and whether there is any shaking or deviation phenomenon by controlling the lifting of the window through the motor. If the window does not rise and fall smoothly, check whether the connection of the synchronous traction belt is loose and whether the weight of the counterweight box is appropriate, and make corresponding adjustments.

[0063] ② Debugging of safety anti-falling locking mechanism

[0064] Under the condition that the synchronous traction belt driving mechanism is working normally, lift the window several times and observe whether the limiting lock head is always retracted inside the limiting member shell without affecting the normal lifting of the window.

[0065] Simulate the failure of the synchronous traction belt driving mechanism, such as manually loosening the synchronous traction belt or cutting off the power supply of the motor, and observe whether the limiting lock head can quickly extend outside the limiting member and accurately lock into the lock slot hole to stop the window from falling. If the limiting lock head does not work normally, check whether the elasticity of the spring is normal and whether the cooperation between the limiting lock head and the open sliding groove and the lock slot hole is smooth, and make corresponding adjustments or replace the parts.

[0066] ③ Debugging of balance adjustment

[0067] Use a level tool to measure the hanging levelness of the window, and adjust the height and horizontal position of the limiting member by rotating the balance adjusting screw rod to make the window reach the horizontal state. During the debugging process, repeatedly check the levelness of the window to ensure that the adjustment effect meets the requirements.

[0068] III. Usage scenarios and operation

[0069] ① Normal usage scenario

[0070] In a laboratory or the like, an experimentalist controls the lifting and lowering of the window according to the experimental requirements through a synchronous traction belt driving mechanism. When the driving mechanism is working normally, the limit lock head is retracted in the limiting part, and the window can be smoothly moved up and down, providing the experimentalist with a suitable operating space.

[0071] ②Fault response scenario

[0072] Once the synchronous traction belt driving mechanism fails, such as the synchronous traction belt breaks or the motor is damaged, the window loses normal support force. At this time, the safety anti-falling locking mechanism immediately comes into play, the spring is quickly released, the limit lock head is pushed out of the limiting part, and is clamped into the locking groove hole on the fume hood cabinet body, the window is immediately stopped from falling and locked, effectively protecting the safety of the experimentalist and the articles in the fume hood.

[0073] ③Maintenance scenario

[0074] When the fume hood is regularly maintained, the wear of the limit lock head, spring, synchronous belt connecting piece and other components can be checked by disassembling the bottom plate and cover plate of the limiting part. If a component is damaged, it can be replaced in time. At the same time, the synchronous belt, synchronous belt wheel, counterweight box and other components of the synchronous traction belt driving mechanism are checked to ensure their normal operation. In addition, according to the use of the window, the suspension level of the window is fine-tuned through the balance adjusting screw rod, to ensure the normal use performance of the fume hood.

[0075] Finally, it should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacements of some technical features, as long as they are within the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made within the scope of the present application should be included in the protection scope of the present application.

Claims

1. A fume hood with a window safety anti-falling function, comprising a fume hood cabinet body, a window movably arranged on the fume hood cabinet body, and a synchronous traction belt driving mechanism connected with the window, characterized in that: The safety anti-falling locking mechanism is provided with a limiting piece, and a limiting lock head is telescopically arranged on the limiting piece; a lock slot hole is arranged on the fume chamber cabinet body and matched with the limiting lock head; when the synchronous traction belt driving mechanism is in normal state, the limiting lock head is retracted into the limiting piece, and the window can be normally lifted; when the synchronous traction belt driving mechanism is invalid, the limiting lock head is extended out of the limiting piece and clamped into the lock slot hole, and the window is stopped from falling and locked.

2. The chemical fume hood with the window safety anti-falling function according to claim 1, characterized in that: The synchronous traction belt driving mechanism comprises a synchronous traction belt, a synchronous belt wheel and a counterweight box; the counterweight box is arranged on the back of the fume chamber; the two ends of the synchronous traction belt are respectively connected with the limiting piece and the counterweight box; the synchronous belt wheel is rotatably arranged on the fume chamber cabinet body; and the synchronous traction belt is engaged with the synchronous belt wheel.

3. The chemical fume hood with the window safety anti-falling function according to claim 1, characterized in that: The limiting piece comprises a shell, and the limiting lock head is rotatably arranged in the shell; an open sliding groove is arranged on the shell corresponding to the locking part of the limiting lock head; a synchronous belt connecting piece is telescopically arranged in the shell; one end of the synchronous belt connecting piece extends out of the shell and is connected with the synchronous traction belt; the other end of the synchronous belt connecting piece is provided with a pin shaft for mounting the limiting lock head; and a spring is coaxially sleeved on the synchronous belt connecting piece.

4. The chemical fume hood with the window safety anti-falling function according to claim 3, characterized in that: The spring is arranged on the shell at one end and on the synchronous belt connecting piece at the other end; when the spring is in compressed state, the limiting lock head is retracted into the shell; and when the spring is completely released, the limiting lock head is extended out of the open sliding groove.

5. The chemical fume hood with the visual window safety anti-falling function according to claim 3, characterized in that: The two sides of the limiting lock head are arc-shaped, the locking part is a tooth structure, and the open sliding groove is a stepped groove.

6. The chemical fume hood with the window safety anti-falling function according to claim 3, characterized in that: The shell comprises a bottom plate and a cover plate which are buckled with each other; the synchronous belt connecting piece connected with one end of the synchronous traction belt is provided with a positioning head; and the fume chamber cabinet body is provided with a falling prevention clamping groove matched with the positioning head.

7. The chemical fume hood with the window safety anti-falling function according to claim 1, characterized in that: The fume chamber cabinet body is provided with a window limiting slot corresponding to the positions of the two sides of the window; and the lock slot hole is arrayed in the window limiting slot from top to bottom.

8. The chemical fume hood with the window safety anti-falling function according to claim 3, characterized in that: The limiting piece is arranged on the fume chamber cabinet body through a balance adjusting screw rod; and a connecting screw hole matched with the balance adjusting screw rod is formed in the bottom of the limiting piece.

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