CN209990866U

CN209990866U - Lifting platform

Info

Publication number: CN209990866U
Application number: CN201920449566.0U
Authority: CN
Inventors: 区赞勋
Original assignee: Guangzhou Jinxin Furniture Co Ltd
Current assignee: Guangzhou Jinxin Furniture Co Ltd
Priority date: 2019-04-03
Filing date: 2019-04-03
Publication date: 2020-01-24
Anticipated expiration: 2029-04-03

Abstract

The utility model provides a lifting platform. The lifting table comprises a table top, an energy conversion device (30) and a leg assembly, wherein the energy conversion device (30) is connected below the table top and used for converting elastic potential energy into auxiliary energy for lifting the table top, the energy conversion device comprises a torsion spring (31), a middle shaft (33) and a transmission (32), the first end of the torsion spring (31) is connected to an input part of the transmission (32), the middle shaft (33) is connected to an output part of the transmission (32), the rotating speed of the input part is smaller than that of the output part, the leg assembly is connected with the middle shaft (33), and in the process of forward rotation or reverse rotation of the middle shaft (33), the leg assembly is shortened or lengthened to enable the table top to descend or ascend. According to the utility model discloses a lifting platform, at the overall process that the mesa ascended, the elastic potential energy of torsional spring storage was not totally released to the required external force that comes from the operator of mesa is less.

Description

Lifting platform

Technical Field

The utility model relates to a field of furniture or production operation equipment field, concretely relates to can change elevating platform of height, this elevating platform can show for desk, chair, operation panel or show stand etc. is applicable to family's furniture, office furniture, teaching table chair and production and uses operation panel etc..

Background

In order to reduce the difficulty of the operator in working, the elevator platform in the prior art may include an energy storage device (hereinafter also referred to as an energy storage device). For example, in the lifting platform using the torsion spring as the energy storage device, the torsion spring can be rotated around its axis by rotating the torsion spring to accumulate elastic potential energy, and then when the table top needs to be lifted, the torsion spring releases the elastic potential energy to provide auxiliary energy for assisting the lifting of the table top. Along with the lifting of the table top, the elastic potential energy of the torsion spring and the gravitational potential energy of the table top are mutually converted.

Assuming that the maximum stroke of the table top of the lifting platform from the lowest position (e.g. 700mm from the ground) to the highest position (e.g. 1200mm from the ground) is 500mm, the torsion spring needs to rotate 5 turns during the whole lifting process of the table top, i.e. the table top is lifted 100mm for each turn of the torsion spring.

Assuming that the torsion arm length of the torsion spring is 0.025m, the torsion spring needs 0.75 N.m of torque every time the torsion spring rotates, namely the elastic potential energy is stored at 0.75 N.m. When the torsion spring rotates for one circle, the generated torsion is 0.75 N.m/0.025 m-30N; when the torsion spring rotates for two circles, the generated torsion force is 60N.

Assuming a total table load of 150N, the table is now to be raised from the lowest position to the highest position. The torsion spring is rotated for 5 circles in advance, the elastic potential energy stored by the torsion spring is 5 multiplied by 0.75 N.m to 3.75 N.m, the torsion force generated by the torsion spring outwards is 150N, and the torsion force is balanced with the total load of the table board. At this point, the table top can be raised with an initial upward momentum.

When the table top rises by 100mm, the torsion spring rotates (rotates in the direction opposite to the preset direction) for one circle, potential energy of 0.75 N.m is released, the potential energy stored by the torsion spring is reduced to 3.75 N.m-0.75 N.m-3 N.m, and the corresponding external torque force is 3 N.m/0.025 m-120N. In order to keep the table top rising at a constant speed, an operator needs to apply an additional 30N upward force to the table top.

By analogy, in order to ensure the stable rising of the table top, the upward force (hereinafter referred to as external force) applied to the table top by an operator needs to be increased continuously in the process of the continuous rising of the table top. When the table top rises by 200mm, the required external force is 60N; when the table top rises by 400mm, the required external force is 120N. The ever-increasing external force requirements place a greater burden on the operator.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome or alleviate at least the not enough of above-mentioned prior art existence, provide a can provide the elevating platform of lasting stable auxiliary force.

The utility model provides a lifting platform, which comprises a platform surface, an energy conversion device and a leg component, wherein the energy conversion device and the leg component are connected below the platform surface,

the energy conversion device is used for converting elastic potential energy into auxiliary energy for lifting the table top and comprises a torsion spring, a middle shaft and a speed changer, wherein the first end of the torsion spring is connected to an input part of the speed changer, the middle shaft is connected to an output part of the speed changer, the rotating speed of the input part is less than that of the output part,

the leg assembly is connected with the middle shaft, and in the process of forward rotation or reverse rotation of the middle shaft, the leg assembly is shortened or lengthened to enable the table top to descend or ascend.

In at least one embodiment, the transmission is a planetary transmission comprising a ring gear, a sun gear, a number of planet gears, and a planet carrier;

the gear ring is fixed, the planet carrier is used as the input component and connected with the torsion spring, and the sun gear is used as the output component and connected with the middle shaft;

the torsion spring is sleeved on the periphery of the middle shaft and is arranged coaxially with the middle shaft.

In at least one embodiment, the transmission includes a large gear as the input member and a small gear as the output member, and axes of rotation of the large gear and the small gear are not collinear.

In at least one embodiment, the lift table further comprises a cross beam secured to the table top, and the energy conversion device further comprises a clutch, a brake fork, and a transmission assembly;

the clutch is fixed on the cross beam, and the middle shaft can penetrate through the clutch around the axis of the middle shaft in a rotating manner;

the brake fork is fixed on the middle shaft and can be selectively locked or released by the clutch; when the brake fork is locked by the clutch, the middle shaft cannot rotate; when the brake fork is released by the clutch, the middle shaft can rotate around the axis of the middle shaft;

the transmission assembly is connected to the second end of the torsion spring, and the second end of the torsion spring can rotate relative to the first end by operating the transmission assembly so as to accumulate elastic potential energy in the torsion spring.

In at least one embodiment, the leg assembly includes a first leg portion, a second leg portion, and a synchronous lifting device, the first leg portion being capable of moving toward or away from the second leg portion in an axial direction of the second leg portion,

the synchronous lifting device comprises:

the supporting frame is in a strip shape;

the two driving wheels are arranged at two end parts of the supporting frame;

the annular transmission part is tightly sleeved on the two transmission wheels by the two transmission wheels; and

the synchronous connector is fixed on the annular transmission part; wherein the content of the first and second substances,

the middle shaft is connected with the annular transmission piece, the supporting frame is fixedly connected to the first leg portion, and the synchronous connector is fixedly connected to the second leg portion.

In at least one embodiment, the first leg portion is disposed about the periphery of the second leg portion.

In at least one embodiment, there are two of the leg assemblies, each disposed on either axial side of the energy conversion device.

In at least one embodiment, the energy conversion device further comprises an outer stub shaft, which is movably nested with the central shaft in the axial direction of each other at the end of the central shaft.

In at least one embodiment, a spring is provided at the junction of the outer stub shaft and the central shaft, and the outer stub shaft can be brought close to the central shaft by pressing the spring.

In at least one embodiment, the leg assembly further includes a pressure cylinder, a cylinder body of the pressure cylinder is fixedly connected with the support frame, and a piston rod of the pressure cylinder is fixedly connected with the second leg portion.

In at least one embodiment, a piston of the pressure cylinder divides the cylinder into a first chamber and a second chamber, the first chamber and the second chamber being in fluid communication, the piston rod extending out of the cylinder from the second chamber,

the cylinder body is divided into a first region and a second region in the axial direction, the second region is closer to the protruding end of the piston rod than the first region,

in the first region, the inner diameter of the cylinder is gradually larger in a direction from the first chamber to the second chamber, and in the second region, the inner diameter of the cylinder is kept constant in a direction from the first chamber to the second chamber.

According to the utility model discloses a lifting platform, at the overall process that the mesa ascended, the elastic potential energy of torsional spring storage was not totally released to the required external force that comes from the operator of mesa is less.

Drawings

Fig. 1 is a schematic structural view of a main body part of an elevating table according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of an energy conversion device according to an embodiment of the present invention.

Fig. 3 and 4 are schematic structural views of a transmission according to an embodiment of the present invention.

Fig. 5 is a schematic structural view of a synchronous lifting device according to an embodiment of the present invention.

Fig. 6 is a schematic structural view of a leg assembly according to an embodiment of the present invention.

Fig. 7 is a schematic view of a partial structure of an assembly of a leg assembly and a beam assembly according to an embodiment of the present invention.

Fig. 8 is a schematic structural view of a pressure cylinder according to an embodiment of the present invention.

Description of the reference numerals

10 a cross beam;

20 legs; 21 a first leg portion; 22 a second leg;

30 an energy conversion device; 31 a torsion spring;

a 32 transmission; 321 a planet carrier; 322 sun gear; 323 a planet wheel; 324 a ring gear; 325 shell;

33 a central axis; 34 an outer stub shaft; 341 a spring; 35 a clutch; 351 a clutch switch; 36 brake forks; 37 a drive assembly; 371 a handle; 372, a scale;

40 synchronous lifting device; 41 a support frame; 42 a drive chain; 43 a synchronous connector; a 44 phase connector; 441 connecting rings;

50 pressure cylinders; a 51 cylinder body; 52 a piston rod; 53 pistons.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the detailed description is only intended to teach one skilled in the art how to practice the invention, and is not intended to exhaust all possible ways of practicing the invention, nor is it intended to limit the scope of the invention.

The specific structure and the use method of the lifting platform according to the present invention are described below with reference to fig. 1 to 8.

The lifting platform of the present embodiment comprises a table top (not shown in the figure), a hollow beam 10 fixed below the table top, an energy conversion device 30 accommodated in an inner cavity of the beam 10, two hollow legs 20 fixed on both sides of the beam 10, a synchronous lifting device 40 accommodated in inner cavities of the legs 20, and a pressure cylinder 50.

The energy conversion device 30 is used for providing first auxiliary energy (first auxiliary power) during the lifting process of a lifting part (the lifting part mainly comprises a table top, and the lifting part is only replaced by the table top when the lifting part is mentioned for convenience in description), and the elastic potential energy accumulated by the energy storage device in the energy conversion device 30 can be converted into the gravitational potential energy of the table top, so that the burden of an operator is reduced.

Referring to fig. 2, the power conversion apparatus 30 includes a torsion spring 31, a transmission 32, a center shaft 33, an outer stub shaft 34, a clutch 35, a brake fork 36, and a transmission assembly 37.

The clutch 35 is fixed to the cross member 10, and the central shaft 33 passes through the clutch 35 and can rotate around its own axis relative to the clutch 35. The brake fork 36 is fixed to the bottom bracket 33, and the brake fork 36 can be selectively locked or released by the clutch 35 via the clutch switch 351. When the brake fork 36 is released by the clutch 35, the middle shaft 33 can rotate forwards or reversely; when the brake fork 36 is locked by the clutch 35, the bottom bracket 33 cannot rotate.

Torsion spring 31 is established in the periphery of axis 33, and the first end of torsion spring 31 links to each other with axis 33 through derailleur 32, and transmission assembly 37 is connected to the second end of torsion spring 31. Transmission assembly 37 is configured to transmit an external force to the second end of torsion spring 31 to rotate torsion spring 31 about its axis. In this embodiment, the transmission unit 37 is a worm gear unit, the transmission unit 37 is connected to a handle 371, the rotation axis of the handle 371 is perpendicular to the rotation axis of the torsion spring 31, and an operator can transmit an external force to the torsion spring 31 by rotating the handle 371. The wall of the beam 10 is further provided with an indicating device 372, and the rotation amplitude of the handle 371 can be displayed through the indicating device 372. The indicating device 372 may be a mechanical pointer, and is linked with the handle 371 through a transmission member such as a rack and pinion; or a digital dial, and the rotation amplitude of the handle 371 is measured by a photoelectric sensor or the like. The operator may know the relative amount of energy stored by torsion spring 31 via indicating device 372.

Implementation of the torsion spring 31 accumulating elastic potential energy: the clutch switch 351 is controlled to lock the brake fork 36 by the clutch 35, and at this time, the handle 371 is rotated, so that the first end of the torsion spring 31 is fixed and the second end thereof is rotated.

Implementation manner of releasing elastic potential energy of torsion spring 31: handle 371 is locked, and the second end of torsion spring 31 is fixed, and control clutch switch 351 this moment makes brake fork 36 released by clutch 35, and the first end of torsion spring 31 rotates for the second end, and drives axis 33 to rotate.

The transmission 32 connects the torsion spring 31 and the center shaft 33 such that the rotation of the torsion spring 31 is transmitted to the center shaft 33 in an enlarged manner. As will be understood by the reader below, the table top is lifted a certain distance, the number of rotation turns corresponding to the central shaft 33 is fixed, and if the central shaft 33 rotates several turns, the torsion spring 31 rotates only a small angle, and the elastic potential energy of the torsion spring 31 is not completely released during the lifting process of the table top. For the same lifting distance, the change of the assisting force provided by the torsion spring 31 is small compared to the adjusting process of completely releasing the elastic potential energy of the torsion spring 31, so that the lifting of the table top is more smooth and the external force required to be dynamically supplemented by the operator is smaller.

Referring to fig. 3 and 4, the specific structure and action of the transmission 32 according to the present embodiment are described below. In order to save the space of the inner cavity of the cross beam 10 and facilitate the position arrangement of the middle shaft 33 and the torsion spring 31, the transmission 32 used in the embodiment is a planetary gear transmission. The transmission 32 includes a planet carrier 321, a sun gear 322, three planet gears 323, a ring gear 324, and a housing 325. The planet carrier 321 is fixed to the first end of the torsion spring 31, and the planet gear 323 is fixed to the planet carrier 321 to rotate around the axis thereof. The central shaft 33 passes axially through the sun gear 322 and is connected in a rotationally fixed manner to the sun gear 322. The outer periphery of the ring gear 324 has notches that mate with protrusions in the housing 325 so that the ring gear 324 is held by the housing.

The operation of transmission 32 corresponds to the release of the elastic potential energy of torsion spring 31. In the process, the gear ring 324 is not moved, the planet carrier 321 is in driving, and the sun gear 322 is in driven, so that the transmission effect of acceleration from the planet carrier 321 to the sun gear 322 is realized.

The advantage of the present invention with the additional transmission 32 will be described with the transmission ratio (i.e., the ratio of rotational speed (angular velocity)) between the carrier 321 and the sun gear 322 as 1: 10. The additional support of the table top discussed herein temporarily does not take into account the effects of the cylinder assembly described below.

Assuming that the torsion arm length of torsion spring 31 is 0.025m, torsion spring 31 requires 7.5N · m of torque for each rotation, i.e. potential energy is stored at 7.5N · m. Therefore, the force transmitted to the bottom bracket 33 through the transmission 32 is 7.5N · m/0.025m/10 — 30N per rotation of the torsion spring 31.

For a table top with a load of 150N that needs to be raised by 500mm, the table top is assumed to be raised by 100mm for each rotation of the central axis 33. Defining the initial state, torsion spring 31 is preset to rotate forward 5 turns, so that torsion spring 31 stores elastic potential energy of 5 × 7.5N · m-37.5N · m, and the force transmitted to middle shaft 33 through transmission 32 is 37.5N · m/0.025 m/10-150N. The support force provided to the table top by the torsion spring 31 at this time is balanced with the load on the table top, and the table top can be raised by giving a slight upward initial momentum to the table top.

After the table top rises 100mm, the central shaft 33 rotates 1 turn, the torsion spring 31 rotates 1/10 turns (36 °) in the opposite direction opposite to the preset rotation direction, and the torsion spring 31 releases the elastic potential energy of 7.5N · m × 1/10, which is 0.75N · m. At this time, the elastic potential energy stored in torsion spring 31 is reduced to 37.5N · m-0.75N · m to 36.75N · m, and the force transmitted by torsion spring 31 through transmission 32 to bottom bracket 33 is reduced to 36.75N · m/0.025m/10 to 147N. The support force provided to the table top by the torsion spring 31 is reduced by 3N compared to the initial state. At the moment, the operator only needs to additionally provide 3N upward external force for the table top, and the table top can still rise at a constant speed.

By analogy, when the table top rises by 200mm, the required external force is 6N; when the table top rises by 400mm, the required external force is 12N. When the table top rises 500mm, the torsion spring 31 rotates 5/10 circles (180 degrees) in the same reverse direction, the elastic potential energy is released to be 3.75 N.m, the stored elastic potential energy of the torsion spring 31 is reduced to 37.5 N.m-3.75 N.m-33.75 N.m, and the force transmitted to the middle shaft 33 by the torsion spring 31 through the transmission 32 is reduced to 33.75 N.m/0.025 m/10-135N. The support force provided to the table top by torsion spring 31 is reduced by only 15N compared to the initial state.

Thus, the external force provided by the operator during the 500mm rise of the table top is greatly reduced compared to prior art solutions that do not use the transmission 32.

Next, referring to fig. 5 to 7, how the table top is lifted and lowered by the rotation of the central shaft 33 will be described.

The synchronous lifting device 40 is connected with the central shaft 33 and the legs 20, and the synchronous lifting device 40 can not only realize the conversion between the rotation of the central shaft 33 and the telescopic motion of the legs 20, but also ensure that the two legs 20 can be synchronously stretched.

Referring to fig. 5, the synchronous lifting device 40 includes a support bracket 41, a driving chain 42, a synchronous connector 43, and a phase connector 44. The supporting frame 41 is in a long strip shape, two ends of the supporting frame 41 are respectively connected with a phase connector 44, and each phase connector 44 comprises a driving wheel. An endless drive chain 42 is mounted on the drive wheels of the two phase connections 44 and is tensioned. The synchronization connector 43 is fixed to the transmission chain 42, and forward and reverse rotation of the transmission chain 42 causes the synchronization connector 43 to reciprocate between the two phase connectors 44. The rotation of the transmission chain 42 is synchronous with the rotation of the transmission wheel, the rotation of the transmission wheel drives the connection ring 441 to rotate, and the connection ring 441 can be connected with the middle shaft 33 in a non-rotatable manner; thus, rotation of central shaft 33 and reciprocation of synchronization connector 43 are mutually constrained.

Referring to fig. 6, the connection relationship between the synchronous lifting device 40 and the leg 20 will be described. The leg 20 comprises a first leg 21 and a second leg 22 nested within each other, the first leg 21 and the second leg 22 being able to move towards or away from each other to effect shortening or lengthening of the leg 20. The support bracket 41 of the synchronous lifting device 40 is fixedly connected to the first leg 21 and the synchronous connector 43 is fixedly connected to the second leg 22. Thus, when the relative positions of the first leg portion 21 and the second leg portion 22 are changed, the position of the synchronization connector 43 on the support frame 41 is changed accordingly, while accompanying the rotation of the connection ring 441. In the present embodiment, since the first leg portion 21 and the second leg portion 22 are nested with each other, the first leg portion 21 is fitted around the outer periphery of the second leg portion 22 so that the first leg portion 21 and the second leg portion 22 do not interfere with the position of the synchronization connector 43 when they move relatively.

Next, how the center shaft 33 is connected to the phase connector 44 will be described with reference to fig. 7. The beam assembly (including the beam 10 and the energy conversion device 30) of the present embodiment can be conveniently disassembled and assembled with the leg assembly (including the legs 20, the synchronous lifting device 40 and the pressure cylinder 50 described further below), so that the lifting platform can be independently packaged and transported in the process of being transported to a customer from a manufacturer, and the logistics cost is saved. The flexible attachment and detachment of the cross beam assembly to the leg assembly is achieved by the outer stub shaft 34 and the spring 341. The middle shaft 33 (not shown in fig. 6) is provided with a hollow structure at both ends, and the outer short shaft 34 can be embedded in the inner cavity at the end part of the middle shaft 33 and is connected with the middle shaft 33 in a non-rotatable way, for example, the cross section of the inner cavity at the end part of the middle shaft 33 and the cross section of the outer short shaft 34 are both hexagonal. The spring 341 is provided at the joint of the outer stub shaft 34 and the middle shaft 33, and in a natural state, the spring 341 keeps the original length, and the outer stub shaft 34 is in an extended state. Outer stub shaft 34 can extend further into the lumen of central shaft 33 upon application of pressure to outer stub shaft 34 in an axial direction toward central shaft 33. The cross-sectional shape of the outer stub shaft 34 is adapted to the cross-sectional shape of the annular hole of the phase connection ring 441, so that the outer stub shaft 34 can just extend into the phase connection ring 441, and the rotation of one of the outer stub shaft 34 or the phase connection ring 441 can drive the other to rotate in the same phase, and the phases of the rotation of the two are restricted, i.e., the two cannot be connected with each other in a relative rotation manner.

Preferably, the distance between the two legs 20 of the completely assembled lifting platform (approximately equal to the distance between the two connection rings 441) is smaller than the distance between the protruding ends of the two outer short shafts 34 of the energy conversion device 30 in a natural state. Thus, when the beam assembly and the leg assembly are mounted, the outer stub shafts 34 are pressed at least partially into the central shaft 33 until both outer stub shafts 34 extend into the corresponding phase connection rings 441. The outer stub shaft 34 will then partially spring back out of the central shaft 33 under the force of the spring 341, making the beam assembly and leg assembly more securely assembled.

It should be understood that the telescoping assembly of outer stub shaft 34 with central shaft 33 is not limited to the above-described manner of nesting outer stub shaft 34 within central shaft 33. For example, the end of the outer stub shaft 34 connected to the central shaft 33 may be configured as a hollow structure so that the central shaft 33 can partially protrude into the inner portion of the outer stub shaft 34.

The cylinder 50 (see fig. 8) in the present embodiment supplies the second assist energy (second assist power) to the table top. In the present embodiment, the pressure cylinder 50 is a pneumatic cylinder, and the cylinder 51 is filled with high-pressure nitrogen gas. The cylinder 51 is fixedly connected to the support frame 41 or the first leg 21, and the piston rod 52 is fixedly connected to the second leg 22. During the raising of the table top, the piston rod 52 continues to extend out of the cylinder 51 to provide auxiliary power.

Preferably, the inner diameter of pressure tube 50 is specially designed to smooth out the output force of piston rod 52 during extension. This is because, since the piston rod 52 occupies a certain space inside the cylinder 51, the volume of the gas inside the cylinder 51 gradually becomes larger and the pressure of the gas inside the cylinder 51 gradually decreases during the outward extension of the piston rod 52. If the surface areas of the upper and lower surfaces of the piston 53 remain unchanged, the outward output force of the piston rod 52 will decrease continuously throughout the outward extension of the piston rod 52. In the preferred embodiment described below, the inner diameter of the cylinder 51 is varied in the axial direction, so that the surface areas of the upper and lower surfaces of the piston 53 are varied during the movement.

The construction of this preferred pressure tube 50 is described below with reference to fig. 8.

The interior of the cylinder 51 is axially divided by the piston 53 into a first chamber C1 and a second chamber C2, the first chamber C1 being in fluid communication with the second chamber C2.

The cylinder 51 is divided into two regions in the axial direction according to the inner diameter of the cylinder 51, defining the extending direction of the piston rod 52 as "up", and the second region is located above the first region. In a direction from the first region to the second region in the axial direction of the cylinder 51, the cylinder inner diameter of the first region gradually becomes larger, and the cylinder inner diameter of the second region remains unchanged.

The piston 53 has a certain elasticity, can be in close contact with the inner wall of the cylinder 51 and can be deformed adaptively according to the change of the inner diameter of the cylinder, during the movement of the piston rod 52 outwardly extending out of the cylinder 51, the difference △ S between the upper and lower surfaces of the piston 53 (the surface of the piston 53 facing the first chamber C1 is the lower surface thereof, and the surface of the piston 53 facing the second chamber C2 is the upper surface thereof) is gradually reduced when the piston 53 moves in the first region, while the difference △ S' between the upper and lower surfaces of the piston 53 is maintained when the piston 53 moves in the second region, the dotted line portions in fig. 8 are schematic positions in the movement track of the piston 53, and table 1 shows the difference between the surface areas of the upper and lower surfaces of the piston 53 at the positions.

TABLE 1

The whole process of extending the piston rod 52 has △ S < △ S', the surface area difference adaptively compensates the air pressure difference in the cylinder body 51 in the process, so that the change of the output force of the piston rod 52 is small, and the auxiliary power provided by the pressure cylinder 50 is smooth.

The following describes the lifting operation process of the lifting platform according to the embodiment with reference to fig. 1 and 2:

(1) lifting platform

In the initial state, the clutch switch 351 is in the connected state, and the brake fork 36 is locked by the clutch 35.

Rotating handle 371 makes torsion spring 31 follow-up positive rotation and accumulate energy, and combines the reading of indicating device 372, makes torsion spring 31 accumulate the elasticity potential energy that suits the total weight of the table top.

The clutch switch 351 is put in an off state. The brake fork 36 is separated from the clutch 35, the torsion spring 31 rotates reversely to release elastic potential energy, and the transmission 32 drives the middle shaft 33 and the outer short shafts 34 at the two ends to rotate, so that the first auxiliary power is transmitted to the synchronous lifting device.

The table top is close to a suspended state by the second auxiliary power provided by the pressure cylinder 50 and the support of the above-mentioned first auxiliary power. The table top can now be lifted slightly giving the table top an initial upward momentum and the piston rod 52 of the pressure cylinder 50 is extended. The legs 20 are extended (the first leg portions 21 rise at a nearly constant speed), and the rising of the first leg portions 21 on both sides is kept synchronized.

In the process of the table-board rising, an operator can give certain artificial external force to the table-board according to the motion state of the table-board.

After the table has reached the desired height, the clutch switch 351 is engaged and the brake fork 36 is locked by the clutch 35. The elongation process of the legs 20, i.e. the raising process of the table top, is terminated and the height of the table top is determined and the gravitational potential energy of the table top is increased.

(2) The lifting platform descends

The clutch switch 351 is in an off state, the brake fork 36 is unlocked from the clutch 35, and the middle shaft 33 and the outer stub shafts 34 at both ends are in a rotatable state.

Lightly pressing the table top gives a downward initial momentum to the table top, and the table top descends under the action of the gravity of the table top. During the descending process of the table top, the central shaft 33 rotates in the forward direction (relative to the reverse rotation of the central shaft 33 and the torsion spring 31 during the ascending process of the lifting table), the brake fork 36 and the torsion spring 31 are driven to rotate in the forward direction, and the torsion spring 31 stores energy.

After the table top reaches the desired height, the clutch switch 351 is connected, the brake fork 36 is locked by the clutch 35, the descending process is terminated, the height of the lifting table is determined, and the gravitational potential energy of the table top is converted into the elastic potential energy of the torsion spring 31.

The utility model discloses at least, one of following advantage has:

(i) the utility model discloses use torsional spring 31 to provide first auxiliary power for the rising of elevating platform, and this auxiliary power transmits for axis 33 and further transmits for synchronous elevating gear 40 via derailleur 32. The transmission 32 performs a lever-like adjustment function in the transmission process of force and motion, and transmits the amplified rotation angle of the torsion spring 31 to the middle shaft 33, so that the elastic potential energy accumulated in the torsion spring 31 is not completely released in the whole process of the table top lifting.

(ii) The transmission 32 adopts a planetary gear transmission structure, the torsion spring 31 is connected to the planet carrier 321 which is an input part of the transmission 32, the middle shaft 33 is connected to the sun gear 322 which is an output part of the transmission 32, so that the torsion spring 31 can be sleeved on the periphery of the middle shaft 33 and is arranged coaxially with the middle shaft 33, the middle shaft 33 can axially penetrate through the transmission 32, and the space of the inner cavity of the beam 10 is saved.

(iii) The synchronous lifting device 40 is connected with the energy conversion device 30, so that the transmission between the rotation of the central shaft 33 and the telescopic motion of the legs 20 is realized, and the synchronous telescopic motion of the legs 20 arranged in pairs can be ensured.

(iv) The outer short shaft 34 and the middle shaft 33 can move a certain distance in the axial direction, so that the synchronous lifting device 40 and the energy conversion device 30 can be conveniently disassembled and assembled. The manufacturer can separately produce and package the leg assemblies, the beam assemblies and the top of the lifting platform for storage, logistics cost and the like, and then leave the overall assembly process of the lifting platform to the consumer for completion.

Of course, the present invention is not limited to the above embodiments, and those skilled in the art can make various modifications to the above embodiments of the present invention without departing from the scope of the present invention. For example:

(i) according to the utility model discloses a lifting platform can not use pressure cylinder 50 to provide second auxiliary power, can be in order to omit the setting of pressure cylinder 50. When the pressure cylinder 50 is used to provide the second auxiliary power, a general pressure cylinder having a cylinder bore that is equal in the axial direction may also be used.

(ii) According to the present invention, the lifting platform can have only one (but not two) legs 20, and at this time, the synchronous lifting device 40 connected to the legs 20 plays a role of transferring the rotation of the middle shaft 33.

(iii) Instead of a planetary gear transmission, the transmission 32 may be a conventional gear transmission, for example, a transmission in which a large gear meshes with a small gear in the transmission 32, and the axes of rotation of the large gear and the small gear are not collinear, in which case the torsion spring 31 is connected to the large gear as an input member, and the middle shaft 33 is connected to the small gear as an output member. Although the common transmission may occupy more space than a planetary transmission, the common transmission has low precision requirement on parts, more flexible transmission ratio setting and convenient maintenance.

(iv) The drive chain 42 may also be a belt, a rope, or other form of endless drive.

Claims

1. A lifting platform comprising a platform surface, an energy conversion device (30) connected below the platform surface and a leg assembly, characterized in that,

the energy conversion device (30) is used for converting elastic potential energy into auxiliary energy for lifting the table top and comprises a torsion spring (31), a middle shaft (33) and a transmission (32), wherein the first end of the torsion spring (31) is connected to an input part of the transmission (32), the middle shaft (33) is connected to an output part of the transmission (32), and the rotating speed of the input part is less than that of the output part,

the leg assembly is connected with the middle shaft (33), and the leg assembly is shortened or lengthened to enable the table top to descend or ascend in the process of forward rotation or reverse rotation of the middle shaft (33).

2. The lift table of claim 1, wherein the transmission (32) is a planetary gear transmission comprising a ring gear (324), a sun gear (322), a number of planet gears (323) and a planet carrier (321);

the ring gear (324) is fixed, the planet carrier (321) is used as the input component to be connected with the torsion spring (31), and the sun gear (322) is used as the output component to be connected with the middle shaft (33);

the torsion spring (31) is sleeved on the periphery of the middle shaft (33) and is arranged coaxially with the middle shaft (33).

3. The lift table of claim 1, wherein the transmission (32) includes a bull gear as the input member and a pinion gear as the output member, the axes of rotation of the bull gear and the pinion gear being non-collinear.

4. The lift table of claim 1, further comprising a cross beam (10) secured to the table top, the energy conversion device (30) further comprising a clutch (35), a brake fork (36), and a transmission assembly (37);

the clutch (35) is fixed on the cross beam (10), and the middle shaft (33) can penetrate through the clutch (35) in a rotating mode around the axis of the middle shaft;

the brake fork (36) is fixed on the middle shaft (33), and the brake fork (36) can be selectively locked or released by the clutch (35); when the brake fork (36) is locked by the clutch (35), the middle shaft (33) cannot rotate; when the brake fork (36) is released by the clutch (35), the middle shaft (33) can rotate around the axis thereof;

the transmission component (37) is connected to a second end of the torsion spring (31), and the second end of the torsion spring (31) can rotate relative to the first end by operating the transmission component (37) so as to enable the torsion spring (31) to accumulate elastic potential energy.

5. The lifting table according to claim 1, characterized in that the leg assembly comprises a first leg (21), a second leg (22) and a synchronous lifting device (40), the first leg (21) being able to approach or move away from the second leg (22) in the axial direction of the second leg (22),

the synchronous lifting device (40) comprises:

a support frame (41) in a strip shape;

the two driving wheels are arranged at two end parts of the supporting frame (41);

a synchronizing connector (43) fixed to the annular transmission member; wherein the content of the first and second substances,

the central shaft (33) is connected with the annular transmission piece, the supporting frame (41) is fixedly connected to the first leg portion (21), and the synchronous connector (43) is fixedly connected to the second leg portion (22).

6. The lifting platform as claimed in claim 5, characterized in that the first leg (21) is fitted around the outer circumference of the second leg (22).

7. The lift table of claim 1, wherein the energy conversion device (30) further comprises an outer stub shaft (34), the outer stub shaft (34) being movably nested with the central shaft (33) in the axial direction of each other at the end of the central shaft (33).

8. The lift table according to claim 7, characterized in that a spring (341) is provided at the connection of the outer stub shaft (34) to the central shaft (33), the outer stub shaft (34) being able to be brought closer to the central shaft (33) by pressing the spring (341).

9. The lift table of claim 5, wherein the leg assembly further comprises a pressure cylinder (50), a cylinder body (51) of the pressure cylinder (50) being fixedly connected to the support frame (41), and a piston rod (52) of the pressure cylinder (50) being fixedly connected to the second leg (22).

10. The lift table of claim 9, wherein a piston (53) of the pressure cylinder (50) divides the cylinder (51) into a first chamber (C1) and a second chamber (C2), the first chamber (C1) and the second chamber (C2) being in fluid communication, the piston rod (52) extending out of the cylinder (51) from the second chamber (C2),

the cylinder (51) is divided into a first region and a second region in the axial direction, the second region being closer to the protruding end of the piston rod (52) than the first region,

in the first region, the inner diameter of the cylinder (51) becomes gradually larger in a direction from the first chamber (C1) to the second chamber (C2), and in the second region, the inner diameter of the cylinder (51) is kept constant in a direction from the first chamber to the second chamber.