CN111870025B

CN111870025B - Manual lifting table

Info

Publication number: CN111870025B
Application number: CN202010928026.8A
Authority: CN
Inventors: 赵锡锋; 李涛; 纪华; 刘浩; 孙振阳; 纪鑫鑫; 凤春城; 任旭峰
Original assignee: Zhejiang Industry and Trade Vocational College
Current assignee: Zhejiang Industry and Trade Vocational College
Priority date: 2020-09-07
Filing date: 2020-09-07
Publication date: 2022-02-08
Anticipated expiration: 2040-09-07
Also published as: CN111870025A

Abstract

The utility model provides a manual lift table, includes the manual elevating system who sets up on base and the base, and the manual elevating system top is equipped with the table body, manual elevating system includes the flexible branch of air spring, assembly pulley, stay cord and is fixed in the hand spooler of table body bottom, the upper and lower both ends difference fixed connection table body and the base of the flexible branch of air spring, set up between the table body and the base the assembly pulley, the winding has on the assembly pulley the stay cord, stay cord one end fixed connection table body, the hand spooler is connected to the stay cord other end. The hand-operated wire-rewinding device is internally provided with the gear speed reduction transmission mechanism, so that the torque can be amplified, and the pulley block and the pull rope are arranged between the table body and the base, so that the lifting table has a two-stage labor-saving structure, the lifting is very easy, the hand-operated wire-rewinding device also has two-gear functions, and the maneuverability is better.

Description

Manual lifting table

Technical Field

The invention relates to a table, in particular to a manual lifting table.

Background

According to life experience and investigation, the height requirements of the table and the chair under different age stages or different working conditions are different. The height difference easily causes the desk not to match with the user, which hinders the body development of teenagers, and then the desk can easily suffer from spinal diseases due to long-time bending waist and bending back and lowering head. However, the general table basically has no height adjusting function, and the requirements of learning and working cannot be met. Therefore, it is necessary to design a table capable of being lifted, so that the study and the work are more convenient.

In chinese patent No. CN201410532841.7, a multifunctional desk is disclosed, which comprises a desk body lifting mechanism, a drawable storage plate, universal wheels, a pen container, a support frame, and ribs. Table body elevating system link to each other with support frame and floor, it is more firm to make the table body support, it drives the lead screw to rotate the rocking handle through the turbine worm, make screw-nut on the lead screw axial displacement drive the flexible tubule axial displacement of lead screw one end, thereby reach the lift of table body, prior art adopts the cooperation of turbine worm mechanism and screw-nut mechanism to realize going up and down, the gravity of the table body is concentrated in the threaded connection position of lead screw and nut, when putting the heavy object on the table, the lift is more labourious, and the screw thread is crushed easily, the screw thread friction produces the noise easily when going up and down to use in addition, the screw thread also is worn and torn very easily.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a manual lifting table which is simple in structure and labor-saving in lifting.

The invention adopts the technical scheme for solving the technical problems that: a manual lifting table comprises a base and a table body, wherein a manual lifting mechanism is arranged between the base and the table body, the manual lifting mechanism comprises an air spring telescopic supporting rod and a hand-operated wire take-up device, the air spring telescopic supporting rod comprises a cylinder body, a telescopic rod and a valve switch for self-locking, the cylinder body and the telescopic rod are respectively connected with the base and the table body, a pulley block and a pull rope are arranged between the table body and the base, the air spring telescopic supporting rod can jack up the table body after the valve switch is opened, and the hand-operated wire take-up device can press down the table body by tightening the pull rope on the pulley block;

the hand-operated wire winding device comprises a box body, a gear shifting control mechanism and a gear transmission mechanism, wherein the gear transmission mechanism comprises a driving shaft and a driven shaft which are arranged in the box body, and a driving gear and a driven gear which are respectively arranged on the driving shaft and the driven shaft and are meshed with each other;

the gear shifting control mechanism further comprises a lifting control gear wheel and an on-off control gear wheel which are rotatably installed at two ends of the driving shaft, a circumferential fixed connection is formed between the driving gear and the lifting control gear wheel, a circumferential fixed connection is formed between the control wheel and the on-off control gear wheel, a plurality of first clamping grooves and second clamping grooves are circumferentially distributed in inner holes of the lifting control gear wheel and the on-off control gear wheel respectively, the driving shaft is provided with first convex pins and second convex pins at intervals in the axis direction, and the driving shaft is axially movable left and right to realize the clutch of the first convex pins and the first clamping grooves, the second convex pins and the second clamping grooves respectively.

For further perfection, be equipped with first notch on the wheel face of lift control gear wheel, the driving gear lateral part is equipped with the first inserted block with first notch cooperation joint, lift control gear wheel overcoat is equipped with the end cover, and the end cover passes through screw fixed connection box, be equipped with first torsional spring between end cover and the lift control gear wheel, first torsional spring both ends are located respectively between two terminal surfaces of first notch and first inserted block, be equipped with the second notch on the wheel face of on-off control gear wheel, it is equipped with the second inserted block with second notch cooperation joint to control line wheel lateral part, on-off control gear wheel overcoat is equipped with the barrel, and barrel one end and box inner wall integration are connected, be equipped with the second torsional spring between barrel and the on-off control gear wheel, second torsional spring both ends are located respectively between two terminal surfaces of second notch and second inserted block.

Further perfecting, still be equipped with first heavy vestibule and second heavy vestibule respectively on the hole of lift control gear wheel and switch control gear wheel.

Further perfect, it is provided with three fixed column to encircle driving shaft circumference interval on the box inner wall, the end cover lateral part corresponds the interval and is equipped with three fixed plate, and the fixed plate passes through screw fixed connection fixed column terminal surface, be equipped with annular division board between on-off control gear wheel and the gear drive, annular division board's marginal interval is equipped with three bellied fixed part, and the fixed part middle part is equipped with concave position, and concave position and fixed column cooperation carry out circumference fixedly to annular division board.

Further perfected, the transmission ratio of the driving gear to the driven gear is 3/1.

Further perfecting, the assembly pulley includes first loose pulley assembly and second loose pulley assembly, first loose pulley assembly includes the first pulley of installation on first rotation support and the first rotation support, first rotation support is fixed in table body bottom through first fixed component, second loose pulley assembly includes the second and rotates the second pulley of installation on support and the second rotation support, and the second rotates the support and is fixed in the cylinder body lateral part through second fixed component.

The table body comprises a table top plate, a drawer and a supporting frame, wherein the drawer and the supporting frame are arranged on the bottom surface of the table top plate, the first fixing element is of an L-shaped sheet metal part structure and is fixedly connected with the supporting frame through screws, the first fixing element is fixedly connected with one end of a pull rope, the second fixing element is of a hoop part structure, and a boss used for fixing the second rotating support is arranged on the second fixing element.

Further perfection, the left side and the right side of the bottom of the table body are respectively provided with a group of gas spring telescopic supporting rods and pulley blocks.

Compared with the prior art, the invention has the beneficial effects that: 1. the lifting is more labor-saving. The hand-operated wire-rewinding device is internally provided with a speed reduction transmission mechanism of a driving gear and a driven gear, the torque can be amplified, a turbine of a turbine worm mechanism in the prior art is horizontally arranged, the transmission ratio is limited, the gear in the hand-operated wire-rewinding device is vertically arranged, the gear can be made larger, the transmission ratio is larger, the torque amplification effect is better, a pulley block and a pull rope are arranged between the table body and the base, the pulley block can further save labor, so that the lifting table has a two-stage labor-saving structure, if the transmission ratio of the driving gear and the driven gear in the hand-operated wire-rewinding device is 3/1, and the number of the pull rope on the pulley block is 2, the force required during lifting is only 1/6; 2. the bearing capacity is stronger. The weight on the table body is borne by the gas spring telescopic supporting rod, the load-carrying property and the buffering property of the gas spring telescopic supporting rod are good, and if too many heavy objects are suddenly placed on the table body, the lead screw nut mechanism can impact threads, so that the threads are damaged; 3. the installation and the maintenance are convenient. The pull rope is wound on the pulley block and then connected to the hand-operated wire winding device, and the pull rope is easy to replace and has lower cost than a screw rod; 4. the hand-operated wire rewinding device is good in maneuverability. The hand-operated wire-rewinding device has a two-gear switching function, one gear is used for controlling the gear to lift the table body, the other gear is used for opening and closing a valve switch on the telescopic strut of the air spring to form self-locking, before the valve switch on the telescopic strut of the air spring is opened, the hand crank cannot rotate to adjust the lifting height of the table body, and children can be prevented from mistakenly touching the hand crank to change the height of the table body; 5. the sound is little when going up and down, can not produce big screw thread friction noise like feed screw nut mechanism.

Drawings

FIG. 1 is a schematic structural diagram of the present embodiment;

FIG. 2 is a side view of the present embodiment;

FIG. 3 is a cross-sectional view of the hand-operated wire rewinding device;

FIG. 4 is an enlarged schematic view of the structure of the elevation control gear wheel in FIG. 3;

FIG. 5 is an enlarged view of the structure of the shift control wheel of FIG. 3;

FIG. 6 is an exploded view of the hand winding device (omitting the torsion spring);

FIG. 7 is a side perspective view of a hand take-up;

FIG. 8 is a schematic structural diagram of a shift wheel controlled by a switch;

FIG. 9 is a schematic structural view of a shift wheel for elevation control;

fig. 10 is a schematic view of a second sheave assembly;

fig. 11 is a schematic view of a first sheave assembly;

description of reference numerals: 1. a base, 2, a table body, 21, a table top, 22, a drawer, 23, a support frame, 3, a gas spring telescopic support rod, 31, a cylinder body, 32, a telescopic rod, 33, a valve switch, 4, a pulley block, 41, a first pulley component, 411, a first rotating support, 412, a first pulley, 413, a first fixing component, 42, a second pulley component, 421, a second rotating support, 422, a second pulley, 423, a second fixing component, 5, a pull rope, 6, a hand-operated wire-rewinding device, 61, a box body, 611, a cylinder body, 612, a fixing column, 62, a driving shaft, 621, a hand-operated handle, 622, a first convex pin, 623, a second convex pin, 63, a driven shaft, 64, a driving gear, 641, a first insert block, 65, a driven gear, 66, a wire-rewinding wheel, 67, a control wire wheel, 671, a second insert block, 68, a lifting control gear wheel, 681, a first notch, 682, an end cover, 683 and a first torsion spring, 684. the brake device comprises a first sunken cavity, 685, a first clamping groove, 69, a switch control gear wheel, 691, a second notch, 692, a second torsion spring, 693, a second sunken cavity, 694, a second clamping groove, 695, an annular partition plate, 696, a fixing part, 697, a concave part, 7 and a brake line device.

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

with reference to the accompanying drawings: the manual lifting table in the embodiment comprises a base 1 and a table body 2, wherein a manual lifting mechanism is arranged between the base 1 and the table body 2 and comprises a gas spring telescopic supporting rod 3 and a hand-operated wire rewinding device 6, the gas spring telescopic supporting rod 3 comprises a cylinder body 31, a telescopic rod 32 and a valve switch 33 for self-locking, the cylinder body 31 and the telescopic rod 32 are respectively connected with the base 1 and the table body 2, a pulley block 4 and a pull rope 5 are arranged between the table body 2 and the base 1, the gas spring telescopic supporting rod 3 can jack up the table body 2 after the valve switch 33 is opened, and the hand-operated wire rewinding device 6 can press down the table body 2 by tightening the pull rope 5 on the pulley block 4; hand spooler 6 is the self-locking type, through tightening up stay cord 5, cooperates assembly pulley 4, can make the table body 2 push down, reduces the desktop height, and when hand spooler 6 loosened stay cord 5, gas spring telescopic strut 3 was with table body 2 jack-up under the effect of inside atmospheric pressure and spring, improved the desktop height.

The air springs are parts capable of achieving functions of supporting, buffering, braking, height and angle adjusting and the like, and include free air springs, self-locking air springs, traction air springs, free air stopping springs, swivel chair air springs, air pressure rods, dampers and the like. The free gas stopping spring (friction type gas spring, balance type gas spring) is mainly applied to the fields of kitchen furniture, medical appliances and the like. Its characteristics lie in between free type air spring and self-locking type air spring: it can be stopped at any position in the stroke without any external structure, but without additional locking force. The effect is achieved mainly by a controller (a handle or a pull wire). It can also be realized by the extension and contraction of the piston rod. When the desired position is adjusted by the controller, the valve is closed independently and the piston rod is locked in the desired position.

The hand-operated wire winding device 6 comprises a box body 61, a gear shifting control mechanism and a gear transmission mechanism, wherein the gear transmission mechanism comprises a driving shaft 62 and a driven shaft 63 which are arranged in the box body 61, and a driving gear 64 and a driven gear 65 which are respectively arranged on the driving shaft 62 and the driven shaft 63 and are meshed with each other, the gear shifting control mechanism comprises a hand crank 621 fixedly connected to the end part of the driving shaft 62, a wire winding wheel 66 fixedly arranged on the driven shaft 63 and a control wire wheel 67 arranged on the driving shaft 62, the control wire wheel 67 controls the valve switch 33 to be switched on and switched off through a brake wire device 7, and the wire winding wheel 66 is used for tightening and loosening the pull rope 5;

the gear shifting control mechanism further comprises a lifting control gear wheel 68 and a switch control gear wheel 69 which are rotatably installed at two ends of the driving shaft 62, the driving gear 64 and the lifting control gear wheel 68 are circumferentially and fixedly connected, the control wire wheel 67 and the switch control gear wheel 69 are circumferentially and fixedly connected, a plurality of first clamping grooves 685 and second clamping grooves 694 are circumferentially distributed on inner holes of the lifting control gear wheel 68 and the switch control gear wheel 69 respectively, the driving shaft 62 is provided with a first convex pin 622 and a second convex pin 623 at intervals in the axial direction, and the driving shaft 62 respectively realizes the clutch of the first convex pin 622 and the first clamping groove 685 and the clutch of the second convex pin 623 and the second clamping groove 694 in the left-right axial movement process. When first boss pin 622 and first clamping groove 685 are clamped, second boss pin 623 and second clamping groove 694 are separated; when first boss pin 622 and first notch 685 are separated, second boss pin 623 and second notch 694 are clamped.

The wheel face of the lifting control gear wheel 68 in this embodiment is provided with a first notch 681, the side of the driving gear 64 is provided with a first insert 641 engaged with the first notch 681, an end cover 682 is sleeved outside the lifting control gear wheel 68, the end cover 682 is fixedly connected with the box body 61 through a screw, a first torsion spring 683 is arranged between the end cap 682 and the elevation control gear wheel 68, two ends of the first torsion spring 683 are respectively located between the first notch 681 and two end faces of the first insertion block 641, a second notch 691 is arranged on the wheel surface of the switch control gear wheel 69, a second insert 671 matched and clamped with the second notch 691 is arranged on the side part of the steering wheel 67, a cylinder 611 is sleeved outside the switch control gear wheel 69, one end of the cylinder 611 is integrally connected with the inner wall of the box body 61, a second torsion spring 692 is arranged between the cylinder 611 and the switch control gear wheel 69, and two ends of the second torsion spring 692 are respectively located between the second notch 691 and two end faces of the second insert block 671. The inner holes of the lifting control gear wheel 68 and the switch control gear wheel 69 are also respectively provided with a first counter bore hole 684 and a second counter bore hole 693 which can respectively accommodate the first convex pin 622 and the second convex pin 623 after being disengaged, so that the internal structure is more compact.

The pulley block 4 comprises a first pulley component 41 and a second pulley component 42, the first pulley component 41 is fixedly installed on the table body 2, the second pulley component 42 is fixedly installed on the cylinder body 31, and the first pulley component 41 is located right above the second pulley component 42; one end of the pull rope 5 is fixed at the bottom of the table body 2, and then the other end firstly bypasses the lower second pulley component 42 and then is guided to the hand-operated wire-rewinding device 6 through the first pulley component 41, so that two ropes are arranged on the pulley block, and half of labor can be saved.

In this embodiment, the first pulley assembly 41 includes a first rotating support 411 and a first pulley 412 mounted on the first rotating support 411, the first rotating support 411 is fixed at the bottom of the table body 2 through a first fixing element 413, the second pulley assembly 42 includes a second rotating support 421 and a second pulley 422 mounted on the second rotating support 421, and the second rotating support 421 is fixed at the side of the cylinder body 31 through a second fixing element 423, so that the distance between the first pulley assembly 41 and the second pulley assembly 42 is shortened, and the length of the pull rope 5 on the pulley block is short and is not easy to hook.

In this embodiment, the table body 2 includes a table top 21, a drawer 22 disposed on a bottom surface of the table top 21, and a supporting frame 23, the first fixing element 413 is an L-shaped sheet metal component structure, the first fixing element 413 is fixedly connected to the supporting frame 23 through a screw, the first fixing element 413 is fixedly connected to one end of the pull rope 5, the second fixing element 423 is a hoop structure, the pulley is conveniently mounted, and the second fixing element 423 is provided with a boss for fixing the second rotating support 421.

In this embodiment, three fixing posts 612 are circumferentially arranged on the inner wall of the box 61 at intervals around the driving shaft 62, three fixing plates are correspondingly arranged on the side portion of the end cover 682 at intervals, the fixing plates are fixedly connected to the end faces of the fixing posts 612 through screws, an annular partition plate 695 is arranged between the switch control gear wheel 69 and the gear transmission mechanism, three raised fixing portions 696 are arranged at intervals on the edge of the annular partition plate 695, a concave portion 697 is arranged in the middle of the fixing portion 696, and the concave portion 697 is matched with the fixing posts 612 to circumferentially fix the annular partition plate 695. The annular partition plate 695 can function as a mechanism for separating the switch control gear wheel 69 from the gear transmission mechanism, and can prevent the switch control gear wheel 69 and the driving gear 64 from being affected by each other. The transmission ratio of the driving gear 64 to the driven gear 65 is 3/1, which can save 2/3 of effort. A group of gas spring telescopic supporting rods 3 and pulley blocks 4 are respectively arranged on the left side and the right side of the bottom of the table body 2, so that the bearing is more balanced, and pull ropes on the pulley blocks 4 on one side far away from the hand-operated wire winding device 6 can be collected on the hand-operated wire winding device 6 through leather hoses.

The working process is as follows: as shown in fig. 1-11, at the beginning, the valve switch 33 of the gas spring telescopic strut 3 is closed, the gas spring telescopic strut 3 is self-locked, the driving shaft 62 is pressed into a distance through the hand crank 621, so that the first protruding pin 622 is separated from the first blocking slot 685 on the lifting control gear wheel 68 to reach the first counterbore hole 684, the circumferential fixation between the driving shaft 62 and the lifting control gear wheel 68 is released, meanwhile, the second protruding pin 623 is blocked into the second blocking slot 694 from the second counterbore hole 693 on the switching control gear wheel 69, the circumferential fixation between the driving shaft 62 and the switching control gear wheel 69 is realized, then the hand crank 621 is rotated to drive the switching control gear wheel 69 on the driving shaft 62 to rotate, the switching control gear wheel 69 drives the operating reel 67 to rotate forwardly, the operating reel 67 opens the valve switch 33 through tightening the brake wire of the brake wire device 7, so that the gas spring telescopic strut 3 is ventilated inside and outside, then the driving shaft 62 is pulled out a distance by the hand crank 621, so that the first convex pin 622 is clamped into the first clamping groove 685 again, the circumferential fixation of the driving shaft 62 and the lifting control gear wheel 68 is realized, the second convex pin 623 is separated from the second clamping groove 694, the circumferential fixation of the driving shaft 62 and the switch control gear wheel 69 is released, the second torsion spring 692 has a one-way transmission function, the position of the switch control gear wheel 69 can be maintained, the state of the valve switch 33 is kept, then, the hand crank 621 is rotated again, the lifting control gear wheel 68 on the driving shaft 62 is driven to rotate through the hand crank 621, the lifting control gear wheel 68 drives the driving gear 64 to rotate, the driving gear 64 is meshed with the driven gear 65, the take-up pulley 66 on the driven shaft 63 is driven to rotate forwards or backwards, the pull rope 5 is tightened or loosened, the length of the telescopic support rod 3 of the gas spring is adjusted by matching with the pulley block 4, the table body 2 is lifted, and the height of the table top is adjusted; after the height of the tabletop is adjusted, the driving shaft 62 is pressed in again, at this time, the driving shaft 62 is separated from the lifting control gear wheel 68, the first torsion spring 683 maintains the position of the lifting control gear wheel 68, the driving gear 64 is temporarily kept still, then the driving shaft 62 controls the switch to control the gear wheel 69 to rotate reversely, the switch 33 of the valve is closed, the telescopic gas spring supporting rod 3 is locked, the height of the tabletop is fixed, and finally the driving shaft 62 is pulled out again, so that the height adjustment of the tabletop is completed. The first torsion spring 683 and the second torsion spring 692 are clutch torsion springs and have a one-way damping effect, so that the lifting control gear wheel 68 and the switch control gear wheel 69 are smooth in one rotation direction, and are damped in the reverse rotation, so that the valve switch 33 cannot be automatically closed under the action of the spring of the brake cable device 7 when the switch control gear wheel 69 opens the valve switch 33, and meanwhile, the telescopic rod 32 of the gas spring telescopic strut 3 cannot be suddenly lifted under the action of internal high-pressure air pressure or the spring, and the first convex pin 622 can be conveniently clamped into the first clamping groove 685 to control the driving gear 64 to adjust the height of the table top.

While the invention has been shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

Claims

1. The utility model provides a manual lift table, includes base (1) and the table body (2), is equipped with manual elevating system, characterized by between base (1) and the table body (2): the manual lifting mechanism comprises an air spring telescopic supporting rod (3) and a hand-operated take-up device (6), the air spring telescopic supporting rod (3) comprises a cylinder body (31), a telescopic rod (32) and a valve switch (33) for self-locking, the cylinder body (31) and the telescopic rod (32) are respectively connected with a base (1) and a table body (2), a pulley block (4) and a pull rope (5) are arranged between the table body (2) and the base (1), the air spring telescopic supporting rod (3) can jack the table body (2) after the valve switch (33) is opened, and the hand-operated take-up device (6) can press the table body (2) downwards by tightening the pull rope (5) on the pulley block (4);

the hand-operated wire winding device (6) comprises a box body (61), a gear shifting control mechanism and a gear transmission mechanism, wherein the gear transmission mechanism comprises a driving shaft (62) and a driven shaft (63) which are installed in the box body (61), and a driving gear (64) and a driven gear (65) which are respectively installed on the driving shaft (62) and the driven shaft (63) and are meshed with each other, the gear shifting control mechanism comprises a hand crank (621) fixedly connected to the end part of the driving shaft (62), a wire winding wheel (66) fixedly installed on the driven shaft (63) and an operating wire wheel (67) installed on the driving shaft (62), the operating wire wheel (67) controls a valve switch (33) to be switched through a brake wire device (7), and the wire winding wheel (66) is used for tightening and loosening a pull rope (5);

the gear shifting control mechanism further comprises a lifting control gear wheel (68) and a switch control gear wheel (69) which are rotatably installed at two ends of the driving shaft (62), the driving gear (64) and the lifting control gear wheel (68) are circumferentially and fixedly connected, the control wire wheel (67) and the switch control gear wheel (69) are circumferentially and fixedly connected, a plurality of first clamping grooves (685) and second clamping grooves (694) are respectively and circumferentially distributed on inner holes of the lifting control gear wheel (68) and the switch control gear wheel (69), the driving shaft (62) is provided with a first convex pin (622) and a second convex pin (623) at intervals in the axis direction, and the driving shaft (62) respectively realizes the clutch of the first convex pin (622) and the first clamping grooves (685) and the clutch of the second convex pin (623) and the second clamping grooves (694) in the left-right axial movement process.

2. A manually liftable table according to claim 1, wherein: the wheel surface of the lifting control gear wheel (68) is provided with a first notch (681), the side part of the driving gear (64) is provided with a first plug block (641) which is matched and clamped with the first notch (681), the lifting control gear wheel (68) is sleeved with an end cover (682), the end cover (682) is fixedly connected with the box body (61) through a screw, a first torsion spring (683) is arranged between the end cover (682) and the lifting control gear wheel (68), two ends of the first torsion spring (683) are respectively arranged between two end surfaces of the first notch (681) and the first plug block (641), the wheel surface of the switch control gear wheel (69) is provided with a second notch (691), the side part of the control wheel (67) is provided with a second plug block (671) which is matched and clamped with the second notch (691), the switch control gear wheel (69) is sleeved with a cylinder body (611), one end of the cylinder body (611) is integrally connected with the inner wall of the box body (61), a second torsion spring (692) is arranged between the cylinder (611) and the switch control gear wheel (69), and two ends of the second torsion spring (692) are respectively positioned between the second notch (691) and two end faces of the second insertion block (671).

3. A manually liftable table according to claim 2, wherein: and the inner holes of the lifting control gear wheel (68) and the switch control gear wheel (69) are respectively provided with a first sunk hole cavity (684) and a second sunk hole cavity (693).

4. A manually liftable table according to claim 3, wherein: three fixed columns (612) are arranged on the inner wall of the box body (61) in a surrounding mode at intervals in the circumferential direction of the driving shaft (62), three fixing plates are arranged on the side portion of the end cover (682) in a corresponding interval mode, the fixing plates are fixedly connected with the end faces of the fixed columns (612) through screws, an annular partition plate (695) is arranged between the switch control gear wheel (69) and the gear transmission mechanism, three protruding fixing portions (696) are arranged at the edge of the annular partition plate (695) in an interval mode, a concave portion (697) is arranged in the middle of each fixing portion (696), and the annular partition plate (695) is circumferentially fixed through the matching of the concave portion (697) and the fixed columns (612).

5. A manually liftable table according to claim 1, wherein: the transmission ratio of the driving gear (64) and the driven gear (65) is 3/1.

6. A manually liftable table according to claim 1, wherein: the pulley block (4) comprises a first pulley assembly (41) and a second pulley assembly (42), the first pulley assembly (41) comprises a first rotating support (411) and a first pulley (412) installed on the first rotating support (411), the first rotating support (411) is fixed to the bottom of the table body (2) through a first fixing element (413), the second pulley assembly (42) comprises a second rotating support (421) and a second pulley (422) installed on the second rotating support (421), and the second rotating support (421) is fixed to the side of the cylinder body (31) through a second fixing element (423).

7. A manually liftable table according to claim 6, wherein: the table body (2) comprises a table top plate (21), a drawer (22) and a supporting frame (23) which are arranged on the bottom surface of the table top plate (21), a first fixing element (413) is of an L-shaped sheet metal part structure, the first fixing element (413) is fixedly connected with the supporting frame (23) through screws, the first fixing element (413) is fixedly connected with one end of a pull rope (5), a second fixing element (423) is of a hoop part structure, and a boss used for fixing a second rotating support (421) is arranged on the second fixing element (423).

8. A manually liftable table according to claim 1, wherein: the left side and the right side under the table body (2) are respectively provided with a group of gas spring telescopic supporting rods (3) and pulley blocks (4).