Manual lifting student desk and chair for classroom teaching

Abstract

The utility model discloses a manual lifting student desk and chair for classroom teaching. The manual lifting student desk and chair comprises a hollow desk leg sleeve, a transmission mechanism, a hand-cranking locking mechanism and a lifting mechanism. The lifting mechanism comprises lifting movable table legs and pulley assemblies; the transmission mechanism comprises a driving wheel, a driving arm with a notch, a transmission shaft and a take-up wheel, and a torsional spring bolt is arranged on the take-up wheel; the hand-cranking locking mechanism comprises a locking disc, a hand-cranking arm, a handle and a torsional spring arranged in a torsional spring cavity of the locking disc. The two ends of the driving arm are matched with torsional spring hooks at the two ends of the torsional spring, and the torsional spring bolt is located at the notch of the driving arm. The lifting mechanism is driven by the torsion spring bolt during lifting, self-locking can be achieved by means of limitation of the torsion spring on the torsion spring bolt when rotation is stopped, lifting and locking can be achieved only by shaking and locking the hand-cranking device on the basis that an additional self-locking mechanism is not added, the difficulty of operating the lifting mechanism is greatly reduced, and the lifting and locking efficiency is improved. In addition, the lifting is more stable, and meanwhile, the fault occurrence probability is also reduced.

Description

Technical Field

[0001] The present invention relates to a desk and chair, and in particular to a manually liftable student desk and chair for classroom teaching in schools. Background Art

[0002] The statements in this section only provide background information related to the present disclosure, and these statements may constitute prior art. In the process of implementing the present utility model, the inventor found that there are at least the following problems in the prior art.

[0003] In school learning and teaching activities, we found that: from kindergarten to high school, children's physical development is generally faster; and the physical development speed of different children in the same age group is also very different. Therefore, the height requirements of desks and chairs for the same students in different stages and different students in the same stage are different. However, the desks and chairs currently used in schools do not have any lifting and adjustment functions, which are completely unable to meet the needs of children's classroom learning, resulting in incorrect sitting postures for children, which has a great impact on their physical development. Many children have been bending over for a long time, resulting in hunchbacks (commonly known as shovel backs), and their vision has generally declined. Therefore, it is necessary to design a liftable desk and chair so that students always have a set of desks and chairs that suit them throughout the entire learning process in school, which is beneficial to their physical and mental health development, and convenient for them to sit in a comfortable state when studying.

[0004] Because the electric solution requires laying wires on the classroom floor, or installing batteries, there are great safety hazards, and the electric lift is expensive, so it is not suitable for classroom teaching in schools. Only manual lift chairs are suitable.

[0005] At present, there are three ways to manually lift tables and chairs:

[0006] The first is the lifting of worm gears. A multifunctional desk is disclosed in the Chinese patent document with patent number CN201410532841.7, in which the lifting mechanism of the table body is connected to the support frame and the rib plate, so that the table body support is more stable, and the crank is turned to drive the screw through the worm gear, so that the screw nut moves axially on the screw and drives the telescopic small tube at one end of the screw to move axially, thereby achieving the lifting of the table body. Since this structure requires the use of a turbine, a worm, a nut, (some are nut screws, bevel gears), the cost of the turbine worm and bevel gear is relatively high, and the turbine, worm, nut, bevel gear, etc. need to be precisely meshed, otherwise it is easy to be misaligned during use and cannot be lifted normally. In addition, because the gravity of the table body is concentrated on the threaded connection position of the screw and the nut, when heavy objects are placed on the table, lifting is more difficult, and the thread is easily crushed.

[0007] The second is the lifting by gas spring (or hydraulic spring). A manual lifting table is disclosed in a Chinese patent document with the patent number CN111870025B. The manual lifting table includes a base and a manual lifting mechanism provided on the base, and a table body is provided at the top of the manual lifting mechanism. The manual lifting mechanism includes a gas spring telescopic rod, a pulley group, a pulling rope, and a manual wire winder fixed to the bottom of the table body. The upper and lower ends of the gas spring telescopic rod are respectively fixedly connected to the table body and the base. The pulley group is arranged between the table body and the base, and the pulling rope is wound around the pulley group. One end of the pulling rope is fixedly connected to the table body, and the other end of the pulling rope is connected to the manual wire winder. The gas spring is controlled by the manual wire winder through the pulling rope and the pulley group to realize the lifting of the table body.

[0008] In the above solution, the hand-crank locking device controls the gas spring through the pulling rope and the pulley group to realize the lifting of the table body, and the structure is complex. The gas spring structure has strict requirements on the strength of the cylinder and the quality of the gas filled into the cylinder. Otherwise, the cylinder seal is not good, or inferior gas is filled, which is very easy to malfunction and even cause an explosion accident. Therefore, the cost is higher and the potential safety hazard is greater.

[0009] In these first and second solutions, there is also a common drawback: the hand crank is exposed. When such desks and chairs are placed in the classroom, it will interfere with students' activities during breaks, easily catch and pull students' clothes and trousers, resulting in students falling, which has a relatively large potential safety hazard. Some make the handle a detachable device and remove it when not in use, but it is easy for students to play with it and it may hit people at any time, presenting a great potential safety hazard.

[0010] In view of the defects of the above two lifting mechanisms, the applicant applied for the following third type of patent.

[0011] The third is the lifting by gear and rack. The applicant's previously applied patent with the patent number ZL202222515483.1 and the patent name "A Lifting Locking Device and Desks and Chairs Based on the Device" is like this. The manual lifting desks and chairs include table legs, two lifting locking devices on the two side table legs, which are connected by a transmission shaft. The rack is arranged on the table leg columns. The lifting locking device includes a rack, a gear meshing with the rack, and a transmission shaft fixedly arranged at the center of the gear; the inner ring of the bearing is fixed on the transmission shaft, the driving wheel is placed outside the locking disc and fixedly connected to the transmission shaft. A hand crank arm is arranged on the driving wheel, and one end of the hand crank arm is connected to one end of the transmission shaft through a hand crank arm folding device, and a handle is arranged at the other end of the hand crank arm; a driving wheel groove and a locking disc groove for accommodating the hand crank arm are respectively arranged on the driving wheel and the locking disc; a handle lock hole is arranged on the locking disc groove. When the desks and chairs are lifted to the appropriate position, the hand crank arm is embedded in the groove, and the handle is buckled into the lock hole.

[0012] The above patent can well fold up the hand crank, and has a simple structure, which is convenient for lifting and locking operations.

[0013] However, the applicant found that when the product is actually used, when the rack and pinion are lifted or lowered to a certain position, once the force applied to the hand-crank device stops, since it cannot be locked synchronously immediately, the entire lifting device will slide down rapidly, resulting in the failure of the lifting operation.

[0014] In fact, there are similar defects in the worm and worm gear lifting or the gas spring (or hydraulic spring). Since the entire table body and its load are borne by the lifting mechanism below, and there are usually a lot of books piled on student desks, during the period from when the hand crank of the lifting mechanism stops rotating to when it is locked, once the force applied to the hand crank is released, due to gravity, the lifting mechanism is very likely to slide down in the reverse direction, further resulting in the failure of the lifting operation and even possibly damaging the components of the lifting mechanism.

[0015] Taking the multi-functional desk with worm and worm gear as an example, when the lifting stops and the hand crank is released, the gravity of the desktop will inevitably cause the desktop to drive the worm to slide down. And since the transmission ratio of its lifting mechanism is limited, it can only be achieved by lengthening or shortening the hand crank to change the torque. Moreover, the rotation directions of the hand crank and the transmission shaft are perpendicular to the rotation direction of the worm and worm gear, and bevel gears are needed to change the rotation direction, increasing the failure rate. In addition, since the nut and screw bear the weight and lock, if the material strength of the nut and screw is not enough, the thread is easily damaged, resulting in the entire mechanism being unable to operate normally.

[0016] For a manually adjustable desk using a gas spring for lifting, although it has a strong bearing capacity, it has high requirements for manufacturing processes and materials. Otherwise, the sealing is not good, resulting in the failure of lifting. And its control system is complex, with many accessories used, including gear sets, pulley sets, ropes, and gas springs. During the operation process, the hand crank needs to be pushed and pulled multiple times to shift gears, and the process is cumbersome, which will also increase the failure rate. Although the patent applicant of the manually adjustable desk uses torsion springs (including the first torsion spring and the second torsion spring) to maintain the position of the switch control gear wheel, so that when the switch control gear wheel opens the valve switch, the valve switch will not automatically close under the action of the spring of the brake wire device, and at the same time, the telescopic rod of the telescopic support rod of the gas spring will not suddenly bounce up under the action of the internal high-pressure air pressure or spring, hoping to prevent the reverse downward slide in this way to facilitate the subsequent locking operation. However, due to the use of the gas spring for lifting, the above-mentioned torsion spring can only indirectly prevent the lower lifting mechanism through the valve switch and cannot directly perform self-locking control on the lifting mechanism. Once the gas spring has poor sealing, it is impossible to achieve self-locking operation on the lifting mechanism through the torsion spring and the valve switch, and it will also cause the failure of the lifting operation. In addition, since it is a student desk, its relatively large gravity will also bring a large load to the gas spring, easily causing it to be damaged (similar to the damage caused by excessive load on the nut and screw), further resulting in the failure of the lifting operation.

[0017] In summary, because the student desks and chairs bear a large load, in order to improve the success rate of manually adjustable desks and chairs, after rocking to the required height of the desks and chairs, not only the force applied to the rocking device needs to be maintained, but also the locking mechanism needs to be controlled to lock it. When lifting or lowering is required, before unlocking the locking mechanism, it is necessary to apply force to the rocking device in advance, otherwise the lifting mechanism will slide downward prematurely due to the weight of the desks, which is likely to cause injury to the operator. Due to the above reasons, the lifting operation is difficult, the error rate is high, and the components of the lifting mechanism are easily damaged due to the failure of the lifting operation, and even personnel injuries may be caused.

[0018] Of course, an additional self-locking mechanism (such as a one-way rotating gear, a pawl, etc.) can be added for self-locking to avoid sliding. However, on the one hand, it will make the structure of the adjustable desk complex and costly; on the other hand, it is still necessary to separately unlock this mechanism before the lifting operation can be carried out, and the operation is also rather troublesome.

[0019] In addition, the existing turbines, worm gears, long screw rods, nuts, bevel gears, gas springs, and gear sets are costly and not very convenient to repair. This is also a problem to be solved. Summary of the Invention

[0020] Aiming at the above problems, the purpose of the present utility model is to solve a part of the problems in the prior art, or at least alleviate these problems.

[0021] A manually adjustable student desk for classroom teaching, comprising:

[0022] Table legs, including hollow table leg sleeves;

[0023] A transmission mechanism, including a driving wheel, a driving arm, a transmission shaft, and wire winding wheels having the same number as the table leg sleeves; the driving arm includes a first driving arm and a second driving arm, forming a cylindrical body with a notch, and one side surface thereof is connected to the first side surface of the driving wheel; the wire winding wheels are sleeved on the transmission shaft and fixedly connected thereto; a torsion spring locking tongue extending into the notch of the driving arm is provided on the wire winding wheel close to the driving wheel;

[0024] A hand-crank locking mechanism, including a locking disc, a hand-crank, and a two-way torsion spring damping self-locking device; the locking disc is provided with a cavity for the driving wheel and the driving arm to be inserted; one end of the hand-crank is hinged to the second side surface of the driving wheel to drive the driving wheel to rotate; the other end of the hand-crank can be detachably connected to the locking disc to lock the driving wheel; the two-way torsion spring damping self-locking device is a torsion spring disposed in a torsion spring cavity between the locking disc and the driving arm; both ends of the torsion spring are respectively provided with a first torsion spring hook and a second torsion spring hook, corresponding to the positions of the first driving arm and the second driving arm of the driving arm;

[0025] Lifting mechanism, including lifting movable table legs and pulley assemblies that are equal in number to the table leg sleeves; the lifting movable table legs are sleeved inside the hollow table leg sleeves, and a circular hole C for the transmission shaft and torsion spring tongue to pass through is provided at the upper end thereof, and is fixedly connected to the locking disc at a corresponding position on the outer side of the upper end; the top end of the lifting movable table leg is used for connecting with the tabletop; the pulling rope of the pulley assembly is wound around the wire reel, and can drive the lifting movable table leg to move up and down relative to the table leg sleeve through the rotation of the wire reel.

[0026] Optionally, a fixed cross beam B is provided at the bottom end of the lifting movable table leg, and a long slot is provided in the middle; the pulley assembly includes a movable pulley sleeved on the fixed cross beam B; the first end of the pulling rope is fixedly provided at the top end of the table leg sleeve, and the second end is connected to the wire reel after passing around the movable pulley.

[0027] Furthermore, the pulley assembly further includes a fixed pulley and an auxiliary pulley; a fixed cross beam A is provided at the upper end of the table leg sleeve located inside the long slot, and the fixed pulley is sleeved on the fixed cross beam A; the auxiliary pulley is sleeved on the fixed cross beam B; the second end of the pulling rope is connected to the wire reel after passing around the movable pulley, the fixed pulley and the auxiliary pulley in sequence.

[0028] Furthermore, the movable pulley and the auxiliary pulley are connected to the fixed cross beam B through bearings; the fixed pulley is connected to the fixed cross beam A through bearings.

[0029] Optionally, the hand crank includes a hand crank arm and a handle; one end of the hand crank arm is hinged to the second side surface of the driving wheel, and the other end is connected to the handle; the locking disc is provided with a plurality of locking disc grooves and handle lock holes located inside the locking disc grooves, and the driving wheel is provided with an active wheel groove adapted to the width of the locking disc groove, and the direction is the same as the hinging direction of the hand crank arm; the hand crank arm can be folded and embedded into the active wheel groove and the locking disc groove, and the handle is buckled into the handle lock hole.

[0030] Furthermore, the locking disc is a cylindrical disc, and the cavity for the driving wheel and the driving arm to be inserted is a T-shaped cylindrical cavity; the part with a smaller diameter of the T-shaped cylindrical cavity is used to accommodate the driving arm and the torsion spring, and the part with a larger diameter is used to accommodate the driving wheel; the diameter of the torsion spring is equivalent to the diameter of the torsion spring cavity; the surface of the locking disc is provided with locking disc grooves radially and evenly distributed in eight directions from the center of the circle.

[0031] Furthermore, the handle can deflect inward by a certain angle.

[0032] Optionally, the transmission shaft is connected to the lifting movable table leg through a first bearing; a through hole is provided at the center of the driving arm, and the transmission shaft passes through the through hole and is connected to the inner wall of the driving wheel through a second bearing.

[0033] Furthermore, the driving arm formed by the first driving arm and the second driving arm is integrally formed with the driving wheel; the notch of the driving arm accounts for one-fourth of the size of the driving arm.

[0034] Preferably, the pulling rope is a steel wire rope; the table leg further includes a table base provided at the lower end of the table leg sleeve; the tabletop further includes a drawer provided below it.

[0035] A manual lifting student chair for classroom teaching includes the structure of the manual lifting student desk for classroom teaching; the top of the lifting movable table leg is used to connect to the chair surface of the chair.

[0036] The utility model has the following beneficial effects:

[0037] 1. In this application, the driving wheel, the driving arm, the wire winding wheel, the torsion spring are combined with the lifting mechanism. The two ends of the driving arm and the two torsion spring hooks of the torsion spring are used to cooperate with the torsion spring locking tongue on the wire winding wheel. The frictional resistance of the torsion spring is used to control the torsion spring locking tongue, and the self-locking and unlocking of the lifting mechanism are realized through the wire winding wheel and the transmission shaft; at the same time, the rotation of the driving wheel and the driving arm is used to drive the lifting mechanism to realize the lifting of the desks and chairs, greatly simplifying the lifting operation process; and the lifting mechanism is correspondingly improved, greatly reducing the force required for lifting and the load borne by the torsion spring self-locking, greatly reducing the probability of failure and further improving the success rate of the lifting operation. This application does not require adding an additional self-locking mechanism. Only by shaking and locking (or unlocking) the hand crank can the lifting and locking be realized, which not only greatly reduces the difficulty of operating the lifting mechanism, but also makes the lifting more stable, smooth and labor-saving, and at the same time reduces the probability of failure.

[0038] 2. This application can achieve the purpose of labor saving in two ways according to the needs of the table body load. One is to increase or decrease the number of fixed and movable pulleys, thereby increasing or decreasing the number of strands of the steel wire rope; the other is to increase or decrease the diameter of the locking disc, thereby lengthening or shortening the hand crank arm and changing the torque. Both of these methods can directly apply the force to the transmission shaft and the wire winding wheel, thereby realizing the up and down operation of the steel wire rope pulley block without any conversion device. When lifted to the appropriate position, just fold the hand crank arm and buckle the handle into the lock hole, which is extremely unlikely to cause failure.

[0039] 3. Strong load-bearing capacity and firm locking. The entire table body and its load of this application are directly borne by the table base, the table leg sleeves and the cross beam at their tops, the steel wire ropes, the transmission shafts, etc. The torsion spring two-way damping self-locking device and the hand crank arm locking disc fixing device both directly act on the wire reel transmission shaft, with a scientific and reasonable structure, firm locking, and not prone to problems such as the lifting malfunction or even damage that existing equipment is prone to.

[0040] 4. The lifting and locking structure is concealed without any protrusions, and the overall appearance of the set of desks and chairs is clean, tidy, and extremely safe. In this application, the wire reel and the steel wire rope pulley group are all arranged inside the lifting movable table legs. The torsion spring self-locking device and the hand crank arm locking disc fixing device are arranged inside a hollow disc with a diameter of 80 mm to 120 mm and a thickness of 20 mm. Moreover, this disc can be completely embedded in the rib plate on one side of the desks and chairs. Compared with existing hand-cranked lifting desks, the potential safety hazards are greatly reduced.

[0041] 5. Low cost and strong practicability. The pulley group, steel wire ropes, transmission shafts, torsion springs, etc. used in this application are inexpensive. The wire reel, locking disc, hand crank arm, and handle can be formed in one piece by die-casting process for mass production, with extremely low cost.

[0042] 6. Easy to repair and replace, reducing waste and saving resources. The products of this application have a long service life, are simple to disassemble and assemble, and the special components can also be produced into standard spare parts for sale, facilitating repair and replacement and repeated use. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is the overall structure schematic diagram of this application;

[0044] Figure 2 is the perspective view of the front of this application;

[0045] Figure 3 is the schematic diagram of the structure and lifting operation process of the lifting mechanism;

[0046] Among them, Figure 3-1 is the structure diagram of the table leg sleeve; Figure 3-2 is the structure diagram of the lifting movable table leg; Figure 3-3 is the connection schematic diagram of the steel wire rope pulley group; Figure 3-4 is the state diagram when the lifting movable table leg descends to the lowest point; Figure 3-5 is the state diagram when the lifting movable table leg rises to the highest point;

[0047] Figure 4 is the perspective view of the structure of the transmission mechanism;

[0048] Figure 5 is the enlarged structure diagram of the hand-cranked locking device;

[0049] Figure 6Cross-sectional view of the transmission mechanism;

[0050] Figure 7 Partial assembly schematic diagram of the drive arm and the torsion spring;

[0051] Figure 8 Front view of the two-way damping self-locking device;

[0052] Figure 9 Stereogram of the hand-crank locking mechanism;

[0053] Figure 10 Front view of the hand-crank locking mechanism;

[0054] Figure 11 Schematic diagram of the structure with rib plates and enlarged view of the rib plates.

[0055] Wherein: 1 - base; 2 - table leg sleeve; 3 - lifting movable table leg; 4 - long slot; 5 - pull rope; A - fixed cross beam; 6 - fixed pulley; B - fixed cross beam; 7 - movable pulley; 8 - first bearing; 9 - transmission shaft; 10 - wire reel; 10-1 - torsion spring tongue; 11 - locking disc; 12 - torsion spring cavity; 13 - torsion spring; 13-1 - first torsion spring hook; 13-2 - second torsion spring hook; 14 - second bearing; 15 - driving wheel; 15-1. First drive arm; 15-2 - second drive arm; 16 - hand-crank arm; 17 - handle; 18 - driving wheel groove; 19 - locking disc groove; 20 - handle lock hole; 21 - drawer; 22 - tabletop; 23 - rib plate. Detailed implementation manner

[0056] The following further describes the present utility model in conjunction with the accompanying drawings. The embodiments of the present utility model are only used to illustrate the present utility model and do not limit the present utility model. Without departing from the technical idea of the present utility model, various substitutions and changes made according to the common general knowledge and customary means in the art shall all be included within the scope of the present utility model.

[0057] In view of the defect that the existing lifting desks are prone to reverse sliding or even damage to components during the lifting operation, the applicant has designed the following solutions.

[0058] As Figure 1-10 shown, a manual lifting student desk for classroom teaching includes:

[0059] Table legs, including a hollow table leg sleeve 2;

[0060] The transmission mechanism includes a driving wheel 15, a driving arm, a transmission shaft 9, and a wire reel 10 having the same number as the table leg sleeves 2; the driving arm includes a first driving arm 15-1 and a second driving arm 15-2, forming a cylindrical body with a notch, and one side surface thereof is connected to the first side surface of the driving wheel 15; the wire reel 10 is sleeved on the transmission shaft 9 and fixedly connected thereto; a torsion spring locking tongue 10-1 extending into the notch of the driving arm is provided on the wire reel 10 close to the driving wheel 15;

[0061] The hand-cranking locking mechanism includes a locking disc 11, a hand-crank, and a bi-directional torsion spring damping self-locking device; the locking disc 11 is provided with a cavity for the driving wheel 15 and the driving arm to be inserted; one end of the hand-crank is hinged to the second side surface of the driving wheel 15 to drive the driving wheel 15 to rotate; the other end of the hand-crank can be detachably connected to the locking disc 11 to lock the driving wheel 15; the bi-directional torsion spring damping self-locking device is a torsion spring 13 provided in a torsion spring cavity 12 between the locking disc 11 and the driving arm; the two ends of the torsion spring 13 are respectively provided with a first torsion spring hook 13-1 and a second torsion spring hook 13-2, corresponding to the positions of the first driving arm 15-1 and the second driving arm 15-2 of the driving arm;

[0062] The lifting mechanism includes lifting movable table legs 3 having the same number as the table leg sleeves 2 and a pulley assembly; the lifting movable table legs 3 are sleeved in the hollow table leg sleeves 2, and a circular hole C for the transmission shaft 9 and the torsion spring locking tongue 10-1 to pass through is provided at the upper end thereof, and is fixedly connected to the locking disc 11 at a corresponding position on the outer side of the upper end; the top end of the lifting movable table legs 3 is used for connecting with the tabletop 22; the pulling rope 5 of the pulley assembly is wound on the wire reel 10, and can drive the lifting movable table legs 3 to move up and down relative to the table leg sleeves 2 through the rotation of the wire reel 10.

[0063] When using the lifting desk of the present application, after unlocking the hand crank from the locking plate 11, due to the torsion spring tongue 10-1 touching the torsion spring hook of the torsion spring 13, self-locking is formed, and the entire lifting mechanism will not slide down and cause injury. When the hand crank rotates, it will drive the rotation of the driving wheel 15 and the driving arm. While the driving arm touches the torsion spring hook of the torsion spring 13 to release the self-locking, it will also apply a force to the torsion spring tongue 10-1 to make the wire reel 10 and the transmission shaft 9 rotate, thereby driving the lifting mechanism to lift or lower the desktop 22. After the desktop 22 reaches the required height, even if no force is applied to the hand crank anymore, the torsion spring tongue 10-1 will touch the torsion spring hook of the torsion spring 13 again to self-lock automatically. Then lock the hand crank with the locking plate 11, and the entire lifting operation is completed. The lifting operation of the present application is simple and has a low difficulty. It almost only requires two steps: turning the hand crank and locking the hand crank, without the need to keep applying force to the hand crank when unlocking it, nor the need to additionally add a self-locking mechanism. And because the torsion spring 13 directly acts on the lifting mechanism through the torsion spring tongue 10-1 and the wire reel 10 to control the lifting operation, compared with the gas spring lifting mechanism, the situation of damaging the lifting mechanism due to operation failure is greatly reduced, making the lifting operation simpler, more stable, and with a higher success rate.

[0064] In the present application, the transmission shaft 9 does not rotate directly with the rotation of the driving wheel 15, but drives the torsion spring tongue 10-1 of the wire reel 10 to rotate through the driving wheel 15 and the driving arm, thereby driving the transmission shaft 9 fixedly connected to the wire reel 10 to rotate, thus greatly simplifying the self-locking, unlocking, and lifting operations.

[0065] The lifting mechanism of the present application can be implemented in the manner as Figure 2 shown in FIG. 3.

[0066] As Figure 3-2 shown, a fixed cross beam B is provided at the bottom end of the lifting movable table leg 3 for installing the movable pulley 7; a long hole 4 is provided in the middle; as Figure 3-2 shown, the pulley assembly includes a movable pulley 7 sleeved on the fixed cross beam B; the first end of the pulling rope 5 is fixedly provided at the top end of the table leg sleeve 2, and the second end is connected to the wire reel 10 after passing around the movable pulley 7. With the above structure, when the wire reel 10 rotates, the lifting movable table leg 3 can be driven to move relative to the table leg sleeve 2 through the pulling rope 5 and the movable pulley 7, thereby realizing the lifting.

[0067] Of course, other existing lifting mechanisms can also be used, in cooperation with the wire reel 10, the transmission shaft 9, and the driving wheel 15, to realize the lifting operation, such as a rack and pinion.

[0068] The pulling rope 5 is preferably a steel wire rope.

[0069] Although this application uses a torsion spring 13 to prevent sliding and achieve self-locking, due to the large gravity of the student desk, there is still a possibility of lifting failure due to gravity. Although the entire table body and its load in this application are directly borne by the table leg sleeves 2, cross beams, steel wire ropes, transmission shafts 9, etc., and the locking of the two-way torsion spring damping self-locking device and the hand crank and the locking disc 11 all act directly on the wire winding wheel 10 and the transmission shaft 9, with a scientific and reasonable structure and firm locking, if the gravity exceeds the limit, there is still a certain probability that the lifting operation will fail, and it may even damage the components of the lifting mechanism. To avoid the above situation, the applicant selects a pulley assembly and makes the following improvements to the pulley assembly, the lifting movable table legs 3, and the table leg sleeves 2.

[0070] As Figure 2 As shown in Fig. 3-2 or 3-3, the pulley assembly further includes a fixed pulley 6 and an auxiliary pulley; at the upper end of the table leg sleeve 2 located in the long hole 4, there is a fixed cross beam A, and the fixed pulley 6 is sleeved on the fixed cross beam A; the auxiliary pulley is sleeved on the fixed cross beam B; the second end of the pull rope 5 sequentially bypasses the movable pulley 7, the fixed pulley 6, and the auxiliary pulley and then is connected to the wire winding wheel 10. With the above improvements, this application can, according to the load-bearing requirement of the table body, reduce the load on the torsion spring 13 during self-locking by increasing the number of fixed pulleys 6 and auxiliary pulleys, so as to ensure that the torsion spring 13 can self-lock by itself, improving the success rate of the lifting operation. In addition, since the number of fixed pulleys 6 and auxiliary pulleys is increased, the number of strands of the steel wire rope is correspondingly increased, thereby reducing the bearing capacity of each strand of the steel wire rope, avoiding the problem of the steel wire rope of the lifting mechanism breaking, greatly reducing the probability of failure, and further improving the success rate of the lifting operation.

[0071] The number of pulley assemblies and lifting movable table legs 3 in the lifting mechanism is determined according to the number of table leg sleeves 2. As Figure 1 As shown in Fig. 2, a table has two table leg sleeves 2, and there are two sets of pulley groups in total for adaptation, which are respectively arranged in the lifting movable table legs 3 on both sides of the table. There are also two steel wire ropes with equal lengths. One end of each steel wire rope is fixed on the fixed cross beam A of the table leg sleeve 2. Using the fixed cross beam A to install the fixed pulley 6 and fix one end of the steel wire rope can avoid the friction between the steel wire rope and the lifting movable table leg 3, making the lifting smoother. The other end bypasses the movable pulley 7 located inside the lifting movable table leg 3 and then is respectively fixed on the corresponding wire winding wheels 10 at both ends of the transmission shaft 9.

[0072] The movable pulley 7 can be installed at the lower end of the lifting movable table leg 3 by a short-axis crossbeam (i.e., the fixed crossbeam B). The movable pulley 7 and the auxiliary pulley are connected to the fixed crossbeam B through bearings; the fixed pulley 6 is connected to the fixed crossbeam A through a bearing. Among them, the pulley can come with its own bearing and U-shaped groove. Although the movable pulley 7 is fixed relative to the lifting movable table leg 3, it is movable relative to the table leg sleeve 2, and one end of the steel wire rope is fixed to the table leg sleeve 2, so the movable pulley 7 can essentially perform the function of a movable pulley.

[0073] To save effort, a fixed pulley 6 can be installed on the fixed crossbeam A, and a movable pulley 7 and an auxiliary pulley can be installed on the fixed crossbeam B. In this way, the steel wire rope 5 can be wound around four strands, and the lifting operation is very labor-saving.

[0074] The auxiliary pulley is essentially a second movable pulley 7, which cooperates with the fixed pulley 6 to reduce the bearing capacity of each strand of the steel wire rope, as well as the force borne when the torsion spring 13 is self-locked and the hand crank is locked with the locking disc 11. Multiple fixed pulleys 6 and the matching auxiliary pulleys can be added according to the actual situation, so as to better cooperate with structures such as the wire reel 10, the torsion spring 13, the driving arm, the driving wheel 15, and the locking disc 11 to achieve better self-locking and locking, thereby greatly reducing the possibility of failure of the lifting operation and the difficulty of the lifting operation, and extending the service life of the components.

[0075] The lifting movable table leg 3 is a metal pipe that can be sleeved inside the table leg sleeve 2 and should be slightly longer than the table leg sleeve 2. Its top is fixedly connected to the tabletop 22. As Figure 1 shown in Fig. 2, there are also two lifting movable table legs, which are made of metal pipes and are sized to match the table leg sleeve 2. Each lifting movable table leg 3 has an equal long hole 4 on both sides.

[0076] The above-mentioned long hole 4 can be a gap of various shapes, such as a rectangular hole. On both side walls of the part of the lifting movable table leg 3 sleeved inside the table leg sleeve 2, there is a long hole 4 each, so that when the lifting movable table leg 3 is sleeved into the table leg sleeve 2 for lifting operation, the fixed crossbeam A can be located inside the long hole 4, so that the lifting operation will not be affected by the fixed crossbeam A. That is to say, the length of the long hole 4 is the maximum stroke of the lifting of the lifting movable table leg 3.

[0077] A circular hole C of appropriate size is opened at an appropriate position below the tabletop 22 at the upper part of the lifting movable table leg 3, and the transmission shaft 9 and the torsion spring locking tongue 10-1 pass through the circular hole C. The through holes on the inner sides of the two lifting movable table legs 3 can be slightly smaller and only allow the transmission shaft 9 to pass through. Alternatively, the transmission shaft 9 is connected to the lifting movable table leg 3 through a first bearing 8 at the through hole, as Figure 1 or Figure 6 shown.

[0078] To achieve rapid locking after self-locking, reduce the pressure on the torsion spring 13, and reduce the exposure of the accessories of the entire desk, thereby reducing potential safety hazards. For example Figure 9 As shown in Fig. 10, the hand crank includes a hand crank arm 16 and a handle 17; one end of the hand crank arm 16 is hinged to the second side surface of the driving wheel 15, and the other end is connected to the handle 17; the locking disc 11 is provided with a plurality of locking disc grooves 19 and handle lock holes 20 located in the locking disc grooves 19, and the driving wheel 15 is provided with a driving wheel groove 18 adapted to the width of the locking disc groove 19, and the direction is the same as the hinging direction of the hand crank arm 16; the hand crank arm 16 can be folded and embedded into the driving wheel groove 18 and the locking disc groove 19, and the handle 17 is buckled into the handle lock hole 20. Just slightly rotate the hand crank arm 16 first to align the driving wheel groove 18 with the locking disc groove 19 in a straight line; then fold the hand crank arm 16 so that the hand crank arm 16 is embedded into the driving wheel groove 18 and the locking disc groove 19, and buckle the handle 17 into the handle lock hole 20, then the entire lifting desk can be firmly locked, and at the same time, the entire hand crank device can be firmly stored.

[0079] In addition, the upper part of the lifting movable table leg 3 that is longer than the table leg sleeve 2 can be fixedly connected to the rib plate 23 with screws, and the locking disc 11 is embedded in the rib plate 23, as Figure 11 shown.

[0080] With the above structure combined with the concealed design of the lifting mechanism, when locked, except for the locking disc 11 being fixedly attached to the outside of the lifting movable table leg 3 and the transmission shaft 9 being located between the two lifting movable table legs 3, other structures such as the wire reel and the lifting mechanism are all located inside the lifting movable table leg 3, the hand crank is located inside the locking disc 11, and the locking disc 11 can be embedded in the rib plate 23 on the side of the table and chair, making the appearance of the entire set of desks and chairs neat, clean, improving safety, and greatly reducing potential safety hazards. (As Figure 11 shown)

[0081] The locking disc 11 can be fixedly connected to the lifting movable table leg 3 with countersunk head screws.

[0082] For example Figure 6 As shown, the locking disc 11 is a cylindrical disc, and the cavity for the driving wheel 15 and the driving arm to be installed is a T-shaped cylindrical cavity; the part with a smaller diameter of the T-shaped cylindrical cavity is used to accommodate the driving arm and the torsion spring 13, that is, the torsion spring cavity 12, and the part with a larger diameter is used to accommodate the driving wheel 15; the diameter of the torsion spring 13 is equivalent to the diameter of the torsion spring cavity 12.

[0083] For example Figure 9As shown in Fig. 10, the surface of the locking disc 11 is provided with locking disc grooves 19 that are evenly distributed radially in eight directions from the center of the circle and can accommodate the hand crank arm 16. Each locking disc groove 19 is provided with a handle lock hole 20 at one end near the circumference that can accommodate the handle 17, and the size of the lock hole is adapted to the handle 17.

[0084] The handle 17 can deflect inward by a certain angle to facilitate smoothly buckling into and pulling out of the handle lock hole 20, as Figure 6 and Figure 9 shown.

[0085] The torsion spring cavity 12 is actually a cylindrical cavity located inside the locking disc 11, and its diameter is equal to the outer diameter of the torsion spring 13. The torsion spring 13 is placed inside the torsion spring cavity 12 and can rotate freely inside the torsion spring cavity 12.

[0086] The torsion spring locking tongue 10-1 on the outer wall of the wire reel 19 near the locking device 11 passes through the torsion spring 13. Each end of the torsion spring 13 has a hook-shaped end towards the center of the circle, namely the first torsion spring hook 13-1 and the second torsion spring hook 13-2, which are respectively placed on both sides of the torsion spring locking tongue 10-1. The first driving arm 15-1 and the second driving arm 15-2 of the driving arm correspond to the positions of the first torsion spring hook 13-1 and the second torsion spring hook 13-2, so that when the driving wheel 15 rotates, power is applied to the torsion spring through the driving arm and the torsion spring hook. (As Figure 6 and Figure 8 shown)

[0087] At the connection between the lifting movable table leg 3 and the torsion spring cavity 12, a round hole is opened, and its diameter is equal to the inner diameter of the torsion spring.

[0088] As Figure 9 shown in Fig. 10, the hand crank arm 16 and the driving wheel 15 are connected at one end of the driving wheel groove 18 through an existing folding technology device (such as a rotating shaft), and a handle 17 is provided at the other end. The handle 17 is connected at the other end of the hand crank arm 16 through an existing folding technology device (such as a rotating shaft).

[0089] The transmission mechanism mainly consists of a driving arm, a driving wheel 15, a transmission shaft 9, and a wire reel 10.

[0090] As Figure 5 shown, a through hole is provided at the center of the driving arm, and the transmission shaft 9 passes through the through hole and is connected to the inner wall of the driving wheel 15 through the second bearing 14. The second bearing 14 plays a role in connecting the transmission shaft 9 and the driving wheel 15 and makes the driving wheel 15 rotate more smoothly.

[0091] Of course, since the driving wheel 15 drives the transmission shaft 9 to rotate through the driving arm, the torsion spring locking tongue, and the wire reel 10, the transmission shaft 9 may not need to pass through the driving arm, and only the torsion spring locking tongue 10-1 needs to penetrate.

[0092] The driving arms formed by the first driving arm 15-1 and the second driving arm 15-2 are integrally formed with the driving wheel 15; the notch of the driving arm accounts for one-fourth of the size of the driving arm, as Figure 5 shown. The driving arm can be a cylinder with one-fourth cut off, extending into the interior of the torsion spring 13, and integrally formed with the driving wheel 15 in a "T" shape, so as to be accommodated by the locking disc 11 which also has a T-shaped cylinder cavity.

[0093] The driving wheel 15 is embedded in the cavity of the locking disc 11, and there is a driving wheel groove 18 passing through the center of the circle on its surface, which can accommodate the hand crank arm 16.

[0094] As Figure 4 shown, at both ends of the transmission shaft 9 near the inner side walls of the lifting movable table legs 3, they are respectively connected to the lifting movable table legs 3 through first bearings 8 with appropriate sizes. The first bearings 8 play a role in connecting the lifting movable table legs 3 and the transmission shaft 9, and make the transmission shaft 9 rotate more smoothly.

[0095] As Figure 6 shown, the wire reel 10 can be fixed at appropriate positions at both ends of the transmission shaft 9 with countersunk head screws. As Figure 2 shown, there are two wire reels, which are equal in size and inner and outer diameters, and are respectively fixed at corresponding positions at both ends of the transmission shaft 9, and are placed at the upper ends inside the lifting movable table legs 3. On the wire reel 10 near the hand crank locking device, there is a torsion spring locking tongue 10-1 perpendicular to the outer wall of the wire reel 10 on the side facing the torsion spring 13, extending into the torsion spring chamber 12, and placed between the hook-shaped ends at both ends of the torsion spring 13, as Figure 7 or shown in 8.

[0096] As Figure 1 shown, the table leg further includes a table base 1 provided at the lower end of the table leg sleeve 2; the tabletop 22 further includes a drawer 21 provided below it. The lifting movable table legs 3 are respectively sleeved in the table leg sleeves 2 at both ends of the table base 1. The table base 1 and the table leg sleeves 2 can be welded from metal pipes. The two ends of the table base 1 are respectively vertically and fixedly connected to a table leg sleeve 2.

[0097] The fixed pulleys 6 and movable pulleys 7 of the two groups of pulley assemblies have exactly the same models and sizes, the two wire ropes 5 have exactly the same models, thicknesses and lengths, and the two wire reels 10 have exactly the same models and sizes, so as to ensure that the two lifting movable table legs 3 run completely synchronously.

[0098] A manually lifted student chair for classroom teaching includes the structure of the manually lifted student desk for classroom teaching. The top ends of the lifting movable table legs 3 are connected to the chair surface of the chair.

[0099] The structure and function of the lifted chair are basically the same as those of the lifted desk.

[0100] The working principles of the components of this application are as follows.

[0101] Lifting principle:

[0102] When the lifting desks and chairs are in the locked state, as Figure 9 shown, pull out the handle 17 from the handle lock hole 20, hold the handle 17 and make a circular motion with the center of the driving wheel 15, that is, the end of the transmission shaft 9, as the center of the circle and the length of the hand crank arm 16 (plus the radius of the driving wheel 15, as Figure 10 shown) as the radius, driving the driving wheel 15, the first driving arm 15-1 and the second driving arm 15-2 to rotate. As Figure 6 , 7 , and 8 shown, when holding the handle 17 and rotating it clockwise, the hand crank arm 16 and the driving wheel 15 rotate clockwise, the first driving arm 15-1 applies power to the first torsion spring hook 13-1 clockwise, the torsion spring 13 contracts inward, the coils of the torsion spring 13 produce a shrinking deformation, causing the torsion spring 13 to lose the frictional resistance with the torsion spring cavity 12 and release the self-locking, and the torsion spring 13 will rotate clockwise under the drive of the first driving arm 15-1. In this way, when holding the handle 17 and rotating it clockwise, the first driving arm 15-1, the second driving arm 15-2, the driving wheel 15, the hand crank arm 16 and the handle 17 as a whole in the hand crank system and the torsion spring 13 will all rotate clockwise. When the first driving arm 15-1 and the first torsion spring hook 13-1 rotate clockwise together, power will be applied to the torsion spring lock tongue 10-1, so that the torsion spring lock tongue 10-1 drives the wire reel 10 to rotate clockwise, as Figure 8 shown. When the wire reel 10 rotates clockwise, as Figure 3-3 , 3-4, and 3-5 shown, the steel wire rope is tightened and shortened due to the applied power F; because the movable pulley 7 (rotating through its own bearing) and the transmission shaft 9 (rotating through the bearing 8) are both fixedly installed on the lifting movable table leg 3, the length of the BC section of the steel wire rope will not change. Therefore, when the wire reel 10 rotates clockwise and tightens, under the action of the power F, the steel wire rope can only shorten the AB section of the steel wire rope, forcing the lifting movable table leg 3 to rise, thereby driving the table main body system (the lifting movable table leg 3, the drawer 21, the rib plate 23 and the table top 22) and the entire lifting mechanism to rise. On the contrary, when holding the handle 17 and rotating it counterclockwise, the hand crank arm 16 and the driving wheel 15 rotate counterclockwise, the second driving arm 15-2 applies power to the second torsion spring hook 13-2 counterclockwise, the torsion spring 13 still contracts inward, the coils of the torsion spring 13 produce a shrinking deformation, causing the torsion spring 13 to lose the frictional resistance with the torsion spring cavity 12 and release the self-locking, and the torsion spring 13 will rotate counterclockwise under the drive of the second driving arm 15-2, as Figure 8As shown. In this way, when the handle 17 is held and rotated counterclockwise, the second drive arm 15-2, the first drive arm 15-1, the driving wheel 15, the hand crank arm 16 and the handle 17 as a whole in the hand crank system and the torsion spring 13 will all rotate counterclockwise. When the second drive arm 15-2 and the second torsion spring hook 13-2 rotate counterclockwise together, power will be applied to the torsion spring locking tongue 10-1, so that the torsion spring locking tongue 10-1 drives the wire reel 10 to rotate counterclockwise, as Figure 8 shown. When the wire reel 10 rotates counterclockwise, as Figure 3-3 , 3-4, 3-5 shown, the steel wire rope is relaxed due to the applied power F and straightened and lengthened under the action of gravity G; because the movable pulley 7 (rotating through its own bearing) and the transmission shaft 9 (rotating through the bearing 8) are both fixedly installed on the lifting movable table leg 3, the length of the BC section of the steel wire rope will not change. Therefore, when the wire reel 10 rotates counterclockwise and lengthens, under the action of the power F and gravity G of the steel wire rope, only the AB section of the steel wire rope can be lengthened, forcing the lifting movable table leg 3 to descend, thereby driving the table body system (lifting movable table leg 3, drawer 21, rib plate 23 and table top 22) and the lifting mechanism as a whole to descend. Because the transmission shaft 9 and the wire reels 10 at both ends thereof are fixedly connected by countersunk head screws, no matter which direction the torsion spring locking tongue 10-1 rotates, the wire reels 10 at both ends of the transmission shaft 9 will rotate synchronously, as Figure 1 or 2 or 4 shown, realizing the smooth lifting and lowering of the entire table body.

[0103] It should be noted specifically that:

[0104] 1. The first bearing 8 serves to connect the lifting movable table leg 3 and the transmission shaft 9 and makes the transmission shaft 9 rotate more smoothly; the second bearing 14 serves to connect the transmission shaft 9 and the driving wheel 15 of the hand crank and makes the driving wheel 15 rotate more smoothly.

[0105] 2. When the lifting movable table leg 3 is at the lowest position, the steel wire rope on the wire reel 10 is released completely. At this time, no matter whether the hand crank arm 16 rotates clockwise or counterclockwise, the wire reel 10 will tighten the steel wire rope, causing the lifting movable table leg 3 and the table top 22 to rise, and then rotating in the opposite direction, the lifting movable table leg 3 and the table top 22 will descend.

[0106] Two-way damping self-locking working principle:

[0107] As Figure 6As shown in Figures 7 or 8, the wire take-up wheel 10 is fixedly connected to the transmission shaft 9. One end of the transmission shaft 9 together with the torsion spring lock tongue 10-1 on the wire take-up wheel 10 extends into the torsion spring cavity 12, and the torsion spring 13 is placed in the torsion spring cavity 12 with a proper size. When no force is applied to the handle 17 to rotate the hand crank arm 16, the whole device is in a self-locking state. Since the locking disc 11 is fixedly connected to the lifting movable table leg 3, the transmission shaft 9 is connected to the lifting movable table leg 3 through the bearing 8, and the driving wheel 15 is connected to the transmission shaft 9 through the bearing 14; therefore, when the hand crank arm 16 of the hand crank is rotated to drive the driving wheel 15 and the first driving arm 15-1 and the second driving arm 15-2 to rotate, the power applied by the first driving arm 15-1 and the second driving arm 15-2 is not directly applied to the torsion spring lock tongue 10-1, but is applied to the first torsion spring hook 13-1 and the second torsion spring hook 13-2. Whether the first driving arm 15-1 applies force to the first torsion spring hook 13-1 to rotate clockwise or the second driving arm 15-2 applies force to the second torsion spring hook 13-2 to rotate counterclockwise, it will cause the torsion spring coil of the torsion spring 13 to shrink and deform, losing the frictional resistance with the torsion spring cavity 12, thus automatically releasing the self-locking. At the same time of automatic unlocking, the first driving arm 15-1 or the second driving arm 15-2 applies force to the torsion spring lock tongue 10-1 to rotate the wire take-up wheel 10, realizing the lifting of the table and chair. When the force is stopped to rotate the hand crank arm 16, the wire take-up wheel 10 and the torsion spring lock tongue 10-1 will rotate in the opposite direction to the rotation of the hand crank arm 16 before under the action of gravity G. However, no matter which direction the wire take-up wheel 10 and the torsion spring lock tongue 10-1 rotate, they will apply force to the first torsion spring hook 13-1 or the second torsion spring hook 13-2. And no matter whether the torsion spring lock tongue 10-1 applies force to the torsion spring hook 13-1 or the torsion spring hook 13-2, it will cause the torsion spring coil of the torsion spring 13 to expand and deform, thus increasing the frictional resistance between the torsion spring 13 and the torsion spring cavity 12, and the torsion spring cavity 12 exerts circumferential control on the torsion spring 13 to realize self-locking. In short: no matter which direction the hand crank arm 16 is rotated, the torsion spring 13 will automatically release the circumferential control of the torsion spring cavity 12 and automatically unlock; after stopping the hand cranking, under the action of gravity G, no matter which direction the wire take-up wheel 10 and the torsion spring lock tongue 10-1 rotate, it will cause the torsion spring coil of the torsion spring 13 to expand and deform, so that the torsion spring cavity 12 exerts circumferential control on the torsion spring 13 to realize self-locking.

[0108] Working principle of the locking disc for fixing and locking:

[0109] After the lifting desks and chairs stop lifting and achieve self-locking, since the two-way self-locking is maintained by the friction damping between the torsion spring 13 and the torsion spring cavity 12, the bearing capacity of its self-locking device is limited. Therefore, it is necessary to strengthen the locking to avoid the problem of the damping self-locking device malfunctioning due to the excessive load on the tabletop 22 and the drawer 21 (such as a naughty student sitting on the table). When the hand crank arm 16 stops being shaken, the two-way damping self-locking device locks immediately. At this time, just slightly rotate the hand crank arm 16 to align the active wheel groove 18 with the locking disc groove 19 in a straight line, fold the hand crank arm 16 so that the hand crank arm 16 is embedded in the active wheel groove 18 and the locking disc groove 19, and buckle the handle 17 into the handle lock hole 20, then the entire lifting desk can be firmly locked, and at the same time, the entire hand crank device can be firmly stored.

[0110] The above-mentioned fixed connections not specifically specified can be connection methods such as riveting, welding, and bolt connection, and the movable connection can be a connection method such as hinge connection.

[0111] The lifting range of the present utility model: Different models can be produced according to different needs. Different models have different lifting strokes. By the same principle, the chair can also be lifted arbitrarily and reasonably in proportion.

[0112] Although the above has described the specific embodiments of the present utility model in detail, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the spirit and principles of the present utility model, and the modifications or deformations that do not involve creative labor should be included within the protection scope of the present utility model.

Claims

1. A manually adjustable student desk for classroom teaching, characterized in that, Comprising: Table legs, including hollow table leg sleeves (2); A transmission mechanism, including a driving wheel (15), a driving arm, a transmission shaft (9), and take-up wheels (10) having the same number as the table leg sleeves (2); the driving arm includes a first driving arm (15-1) and a second driving arm (15-2), forming a cylindrical body with a notch, and one side thereof is connected to the first side of the driving wheel (15); the take-up wheels (10) are sleeved on the transmission shaft (9) and fixedly connected thereto; a torsion spring locking tongue (10-1) extending into the notch of the driving arm is provided on the take-up wheel (10) close to the driving wheel (15); A manual locking mechanism, including a locking disc (11), a hand crank, and a bi-directional torsion spring damping self-locking device; the locking disc (11) is provided with a cavity for loading the driving wheel (15) and the driving arm; one end of the hand crank is hinged to the second side of the driving wheel (15) to drive the driving wheel (15) to rotate; the other end of the hand crank can be detachably connected to the locking disc (11) to lock the driving wheel (15); the bi-directional torsion spring damping self-locking device is a torsion spring (13) disposed in a torsion spring cavity (12) between the locking disc (11) and the driving arm; the two ends of the torsion spring (13) are respectively provided with a first torsion spring hook (13-1) and a second torsion spring hook (13-2), corresponding to the positions of the first driving arm (15-1) and the second driving arm (15-2) of the driving arm; A lifting mechanism, including lifting movable table legs (3) having the same number as the table leg sleeves (2) and a pulley assembly; the lifting movable table legs (3) are sleeved in the hollow table leg sleeves (2), and a circular hole C for the transmission shaft (9) and the torsion spring locking tongue (10-1) to pass through is provided at the upper end thereof, and is fixedly connected to the locking disc (11) at a corresponding position on the outer side of the upper end; a pulling rope (5) of the pulley assembly is wound around the take-up wheel (10), and can drive the lifting movable table legs (3) to move up and down relative to the table leg sleeves (2) through the rotation of the take-up wheel (10).

2. The manually liftable student desk for classroom teaching according to claim 1, wherein A fixed cross beam B is provided at the bottom end of the lifting movable table leg (3), and a long slot (4) is provided in the middle; the pulley assembly includes a movable pulley (7) sleeved on the fixed cross beam B; a first end of the pulling rope (5) is fixedly provided at the top end of the table leg sleeve (2), and the second end thereof is connected to the take-up wheel (10) after passing around the movable pulley (7); the top end of the lifting movable table leg (3) is used for connecting to a table top (22).

3. The manually adjustable student desk for classroom teaching according to claim 2, wherein, The pulley assembly further includes a fixed pulley (6) and an auxiliary pulley; a fixed cross beam A is provided at the upper end of the table leg sleeve (2) located in the long slot (4), and the fixed pulley (6) is sleeved on the fixed cross beam A; the auxiliary pulley is sleeved on the fixed cross beam B; the second end of the pulling rope (5) is connected to the take-up wheel (10) after sequentially passing around the movable pulley (7), the fixed pulley (6), and the auxiliary pulley.

4. The manually liftable student desk for classroom teaching according to claim 3, characterized in that, The movable pulley (7) and the auxiliary pulley are connected to the fixed cross beam B through bearings; the fixed pulley (6) is connected to the fixed cross beam A through bearings.

5. The manually liftable student desk for classroom teaching according to claim 1, characterized in that, The hand cranker includes a hand crank arm (16) and a handle (17); one end of the hand crank arm (16) is hinged to the second side surface of the driving wheel (15), and the other end is connected to the handle (17); the locking disc (11) is provided with a plurality of locking disc grooves (19) and a handle locking hole (20) located in the locking disc groove (19), and the driving wheel (15) is provided with a driving wheel groove (18) adapted to the width of the locking disc groove (19), and the direction is the same as the hinging direction of the hand crank arm (16); the hand crank arm (16) can be folded and embedded into the driving wheel groove (18) and the locking disc groove (19), and the handle (17) is buckled into the handle locking hole (20).

6. The manually adjustable student desk for classroom teaching according to claim 1 or 5, characterized in that, The locking disc (11) is a cylindrical disc, and the cavity for the driving wheel (15) and the driving arm to be loaded is a T-shaped cylindrical cavity; the part with a smaller diameter of the T-shaped cylindrical cavity is used to accommodate the driving arm and the torsion spring (13), and the part with a larger diameter is used to accommodate the driving wheel (15); the diameter of the torsion spring (13) is equivalent to the diameter of the torsion spring cavity (12); the surface of the locking disc (11) is provided with locking disc grooves (19) evenly distributed radially in eight directions from the center of the circle.

7. The manually liftable student desk for classroom teaching according to claim 5, characterized in that, The handle (17) can deflect inward by a certain angle.

8. The manually adjustable student desk for classroom teaching according to claim 1, wherein The transmission shaft (9) is connected to the lifting movable table leg (3) through a first bearing (8); a through hole is provided in the center of the driving arm, and the transmission shaft (9) passes through the through hole and is connected to the inner wall of the driving wheel (15) through a second bearing (14).

9. The manually liftable student desk for classroom teaching according to claim 1, characterized in that, The driving arm formed by the first driving arm (15-1) and the second driving arm (15-2) is integrally formed with the driving wheel (15); the notch of the driving arm accounts for one-fourth of the size of the driving arm.

10. A manually adjustable student chair for classroom teaching, characterized in that, It includes the structure of the manually liftable student desk for classroom teaching according to any one of claims 1 to 9; the top end of the lifting movable table leg (3) is used to be connected to the seat surface of the chair.

Images