CN107802090B

CN107802090B - Universal folding rack for furniture

Info

Publication number: CN107802090B
Application number: CN201711273278.6A
Authority: CN
Inventors: 林烈志
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-12-06
Filing date: 2017-12-06
Publication date: 2020-10-20
Anticipated expiration: 2037-12-06
Also published as: CN107802090A

Abstract

The invention discloses a universal folding rack for furniture, which comprises a left folding component and a right folding component which are in parallelogram structures, an inner fixing rack which is arranged on the furniture and used for hinging the right folding component, an outer supporting piece which is arranged at the outer end of the left folding component and used for supporting, an outer fixing rack which is arranged at the upper part of the outer supporting piece and used for hinging the left folding component, a linkage rack which is arranged between the left folding component and the right folding component and used for linking the left folding component and the right folding component, and a reinforcing component which is arranged below the left folding component and the right folding component and respectively hinged with the left folding component and the right folding component, wherein the reinforcing component forms a movable diamond structure after being hinged with the left folding component and the right folding component. The universal folding rack for furniture has the advantages of simple structure, firmness, stability, high folding speed, convenience, high stability and the like, can be widely installed on various furniture for use, and effectively saves the use and placement space of the furniture.

Description

Universal folding rack for furniture

Technical Field

The invention relates to the technical field of furniture accessories, in particular to a universal folding frame for furniture.

Background

The folding furniture is folded in a folding mode when not in use, and can compress articles with larger volume as much as possible to reduce the occupied space of the folding furniture. At present, the style of folding furniture is various in modeling, but most of the folding furniture is independent folding furniture, such as folding chairs, folding tables, folding sofas, folding beds and the like, the folding principles adopted by the folding furniture are basically the same, but different folding furniture cannot be used universally, only can be processed and designed independently, and the folding furniture has a common characteristic and can be independent furniture articles capable of moving freely.

Disclosure of Invention

The universal folding frame for the furniture has the advantages of simple structure, firmness, stability, high folding speed, convenience, high stability and the like, can be widely installed on various furniture for use, and effectively saves the use and placement space of the furniture.

The invention can be realized by the following technical scheme:

the utility model provides a general folding leg of furniture, is including the left folding assembly and the right folding assembly that are parallelogram structure, install the interior mount that is used for articulated right folding assembly on furniture, be located the outer support piece that left folding assembly outer end is used for supporting, and install the exterior mount that is used for articulated left folding assembly on outer support piece upper portion, be located the link joint that is used for making left folding assembly and right folding assembly linkage to be connected between left folding assembly and the right folding assembly, be located the below of left folding assembly and right folding assembly and with left folding assembly and right folding assembly articulated reinforcement assembly respectively, form the rhombus structure of activity after reinforcement assembly articulates with left folding assembly and right folding assembly. The outer supporting piece is a supporting frame with or without casters, an outer fixing frame used for hinging the left folding assembly is installed at the upper part of the supporting frame, and when the left folding assembly and the right folding assembly are unfolded to be in a horizontal state, the outer fixing frame and the inner fixing frame used for hinging the left folding assembly and the right folding assembly are distributed relatively.

The universal folding rack for furniture mainly comprises a left folding component and a right folding component which are in a parallelogram structure, an inner fixing rack, an outer fixing rack, a supporting rack and a linkage rack, and has few integral parts and simple structure; the left folding assembly and the right folding assembly are in linkage movement with the right folding assembly in the unfolding and folding processes, and the left folding assembly and the right folding assembly in a parallelogram structure are in linkage connection through the middle linkage frame, the upper linkage shaft and the lower linkage shaft in the movement process, so that the structure is firm, the movement is stable, and the stability of the unfolding and folding processes of the folding frames is effectively ensured; the folding frame can be widely applied to various furniture, such as a computer desktop which can be arranged on a vertical computer desk, an entrance shoe cabinet movable chair, an independent folding chair, a hidden dining table, a file cabinet hidden office table and the like, and has good universality and wide application; the use method after the computer desktop is installed on furniture is specifically described by taking the installation on a vertical computer desk as an example of the use of the computer desktop, at the moment, the computer desktop is a working table top, when the computer desktop is used, the computer desktop is driven by an upper folding component and a lower folding component to extend and expand from the inside to the outside together from the top to the bottom, when the computer desktop is not used, an outer supporting piece is pushed inwards, the computer desktop can be folded from the bottom to the top under the drive of the upper folding component and the lower folding component and from the outside to the inside, and the computer desktop is completely folded when being in a vertical state.

Further, folding subassembly in a left side includes folding arm under a left side and is located the workstation of folding arm top under a left side, the left end of folding arm is articulated with the upper portion and the lower part of external fixation frame respectively under workstation and the left side, the right-hand member of folding arm is articulated with the link gear lower part through lower link gear under a left side, the middle bottom of workstation is articulated with the upper portion of link gear through last link gear, the right-hand member of workstation stretches out the top of link gear to folding subassembly in the right side.

Furthermore, the right folding assembly comprises an upper right folding arm and a lower right folding arm, the left ends of the upper right folding arm and the lower right folding arm are hinged to the upper portion and the lower portion of the linkage frame through an upper linkage shaft and a lower linkage shaft respectively, and the right ends of the upper right folding arm and the lower right folding arm are hinged to the upper portion and the lower portion of the inner fixing frame respectively.

Furthermore, the reinforcing component comprises two reinforcing arms hinged to each other, the outer end portions of the two reinforcing arms are hinged to the left lower folding arm and the right lower folding arm respectively, and the reinforcing component after the hinging is completed forms a movable diamond structure together with the left lower folding arm, the right lower folding arm and the lower linkage shaft. The arrangement of the reinforcing component and the lower folding arm are combined together to form a diamond structure, so that the problem that the working table is shaken or deviated in the unfolding or folding process is effectively avoided, and the stability of the working table in the unfolding or folding process is further ensured.

Furthermore, the outer fixing frame, the inner fixing frame and the linkage frame are all formed by bending and stamping metal plates. The sheet metal part is bent and stamped to form the outer fixing frame, the inner fixing frame and the linkage frame, the rigidity and the strength of the sheet metal part are guaranteed, the sheet metal part is not prone to being damaged or broken, and the service life and the use stability of the furniture are effectively guaranteed.

Further, the external fixation frame comprises an external fixation plate, two ends of the external fixation plate are respectively provided with a bending fixation part, the bending fixation part is provided with a fixation hole which is fixedly connected with the external support piece, the middle part of the external fixation plate is provided with two external pressing blocks which are distributed side by side and extend inwards, and the external pressing blocks are provided with hinge holes.

Further, the internal fixation frame comprises an internal fixation plate, upper and lower layers of internal punching blocks extending outwards are arranged on the internal fixation plate, each layer of internal punching blocks at least comprises two internal punching blocks distributed side by side, and hinge holes are formed in the internal punching blocks.

Furthermore, the linkage frame comprises a linkage plate, two ends of the linkage plate are respectively provided with a bending linkage block, an upper linkage hinge hole and a lower linkage hinge hole are formed in the bending linkage block, a lower linkage shaft is rotatably connected in the lower linkage hinge hole, and an upper linkage shaft is rotatably connected in the upper linkage hinge hole.

Furthermore, two ends of the upper linkage shaft are respectively welded on a side plate of the upper right folding arm, a second linkage gear is welded in the middle of the upper linkage shaft, and the second linkage gear and the upper right folding arm rotate along the linkage frame along with the upper linkage shaft; the bottom welding has the first linkage gear who is connected with the meshing of second linkage gear in the middle of the workstation, two and workstation vertically punching press boards are stamped downwards in the middle of the workstation, have first linkage gear through the fixed axle welding between two punching press boards. When opening or closing and receive and fold the workstation, the motion that is fixed in the workstation bottom produces the circular arc change along with the workstation, and then drives the second linkage gear rather than the meshing connection and carries out the rotation that the radian is the same but opposite direction, effectively increases the frictional force of left side folding assembly and right folding assembly operation process, and then effectively ensures the workstation and expandes or receive the stability of folding in-process, simultaneously, effectively prevent because of the gliding or expansion of workstation self overweight arouse and open, ensure that the workstation is received and is folded the back reliable and stable.

Furthermore, the upper linkage shaft is sleeved with two speed reducing springs, the two speed reducing springs are respectively positioned between the second linkage gears on the two sides of the second linkage gears and the side plates of the upper right folding arm, and adjusting nuts are further arranged between the speed reducing springs and the side plates of the upper right folding arm. The setting of speed reduction spring releases the power of opposite direction to the second linkage gear respectively in the both sides of second linkage gear, further increases the frictional force of second linkage gear, ensures that the workstation expandes and folds the process steadily, and the setting of adjusting nut is used for tightening or relaxing speed reduction spring's pressure intensity.

The universal furniture folding rack has the following beneficial effects:

the universal folding rack for the furniture is mainly composed of a left folding component and a right folding component which are in a parallelogram structure, an inner fixing rack, an outer fixing rack, a supporting rack and a linkage rack, and is few in integral part composition and simple in structure;

secondly, the structure is firm, the stability is good, the left folding assembly, the right folding assembly and the linkage frame which enables the left folding assembly and the right folding assembly to form a linkage connection structure are arranged, so that the left folding assembly and the right folding assembly move in a linkage manner along with the right folding assembly in the unfolding and folding processes of the folding frame, the left folding assembly and the right folding assembly which are in a parallelogram structure are connected in a linkage manner through the linkage frame positioned in the middle and the upper linkage shaft and the lower linkage shaft, and the left folding assembly and the right folding assembly form linkage movement in the movement process, so that the structure is firm, the movement is stable, and the stability of the unfolding and folding processes of the folding frame is effectively ensured;

the folding rack can be widely applied to various furniture, such as a vertical computer desk for use as a computer desktop, an entrance shoe cabinet movable chair, an independent folding chair, a hidden dining table, a file cabinet hidden office table and the like, and has good universality and wide application;

fourthly, the use is simple and convenient, the use method after the computer desktop is arranged on the furniture is specifically described by taking the use of the computer desktop as an example, at the moment, the computer desktop is a working table, when the computer desktop is used, the computer desktop is driven by the upper folding component and the lower folding component to extend and expand from inside to outside together from top to bottom, when the computer desktop is not used, the outer supporting piece is pushed inwards, the computer desktop is driven by the upper folding component and the lower folding component to fold from bottom to top and from outside to inside, and the computer desktop is completely folded when in a vertical state;

fifth, the space usage is small, the folding leg of the invention is mounted on various furniture for use, can be used from top to bottom, from inside to outside, and from bottom to bottom, from outside to inside, and the folding leg is folded, it can be expanded when using, it can be folded to reduce the space usage when not using, effective use space saving.

Drawings

FIG. 1 is a schematic view of a horizontal use state of a workbench in a universal folding rack for furniture, wherein the workbench is in a 0-degree angle state;

FIG. 2 is a front view of the unfolding or folding process of the general folding rack for furniture, wherein the workbench is at an angle of 45 degrees;

FIG. 3 is a back schematic view of the unfolding process or the folding process of the workbench in the universal folding rack for furniture in the state of 45 degrees;

FIG. 4 is a front view of the general folding rack for furniture in a vertical folding state when the working table is at an angle of 90 degrees;

FIG. 5 is a rear view of a general folding rack for furniture, showing a vertical folding state when a table is at an angle of 90 degrees;

FIG. 6 is a schematic diagram showing a half-cut state of a workbench in the universal folding leg for furniture according to the present invention;

FIG. 7 is a partial schematic view of a universal folding stand for furniture in accordance with the present invention;

FIG. 8 is an exploded view of the universal folding stand for furniture in accordance with the present invention;

FIG. 9 is a schematic structural view of a reinforcing member of the universal folding leg for furniture according to the present invention;

FIG. 10 is a schematic structural view of an internal fixing frame in the universal folding leg for furniture according to the present invention;

FIG. 11 is a schematic structural view of an external fixing frame in the universal folding frame for furniture according to the present invention;

fig. 12 is a schematic structural view of a linkage frame in the universal folding frame for furniture.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the following detailed description of the present invention is provided with reference to the accompanying drawings.

As shown in fig. 1 to 6, a universal folding leg for furniture comprises a left folding assembly 30 and a right folding assembly 40 which are in a parallelogram structure, an inner fixing frame 50 which is arranged on the furniture and used for hinging the right folding assembly 40, an outer supporting member 10 which is arranged at the outer end of the left folding assembly 30 and used for supporting, an outer fixing frame 20 which is arranged at the upper part of the outer supporting member 10 and used for hinging the left folding assembly 30, a linkage frame 70 which is arranged between the left folding assembly 30 and the right folding assembly 40 and used for linking the left folding assembly 30 and the right folding assembly 40, and a reinforcing assembly 60 which is arranged below the left folding assembly 30 and the right folding assembly 40 and respectively hinged with the left folding assembly 30 and the right folding assembly 40, wherein the reinforcing assembly 60 forms a movable diamond structure after being hinged with the left folding assembly 30 and the right folding assembly 40. The outer support 10 is a support frame with or without casters, an outer fixing frame 20 for hinging the left folding assembly 30 is mounted on the upper portion of the support frame, and when the left folding assembly 30 and the right folding assembly 40 are unfolded to be in a horizontal state, the outer fixing frame 20 and the inner fixing frame 50 for hinging the left folding assembly 30 and the right folding assembly 40 are distributed oppositely. The universal folding rack for furniture mainly comprises a left folding component 30 and a right folding component 40 which are in a parallelogram structure, an inner fixing rack 50, an outer fixing rack 20, a supporting rack and a linkage rack 70, and has few integral parts and simple structure; the left folding assembly 30, the right folding assembly 40 and the linkage frame 70 which enables the left folding assembly 30 and the right folding assembly 40 to form a linkage connection structure are arranged, so that the left folding assembly 30 and the right folding assembly 40 move in a linkage manner along with the right folding assembly 40 in the unfolding and folding processes of the folding frame, and the left folding assembly 30 and the right folding assembly 40 which are in a parallelogram structure form linkage movement through the linkage connection of the middle linkage frame 70, the upper linkage shaft 412 and the lower linkage shaft 80, and the left folding assembly 40 and the right folding assembly 40 form linkage movement in the movement process, so that the structure is firm, the movement is stable, and the stability of the unfolding and folding processes of the folding frame is effectively ensured; the arrangement of the outer supporting piece 10 is used for supporting the outer part of the workbench 31 after being unfolded, the arrangement of the inner fixing frame 50 is used for integrally installing and fixing the folding frame on a furniture fixing plate or a fixing arm, and the arrangement of the folding frame can be widely applied to various furniture, such as a computer desktop installed on a vertical computer desk, an entrance shoe cabinet movable chair, an independent folding chair, a hidden dining table, a file cabinet hidden office desk and the like, and has good universality and wide application; the use method after the computer desktop is installed on furniture is specifically described by taking the installation on a vertical computer desk as an example of the use of the computer desktop, at the moment, the computer desktop is a workbench 31 surface, when the computer desktop is used, the computer desktop is driven by an upper folding component and a lower folding component to extend and expand from inside to outside together from top to bottom, when the computer desktop is not used, the outer supporting piece 10 is pushed inwards, the computer desktop can be folded from bottom to top under the drive of the upper folding component and the lower folding component from outside to inside, and the computer desktop is completely folded when in a vertical state.

As shown in fig. 9 to 12, the external fixing frame 20, the internal fixing frame 50 and the linking frame 70 are all formed by bending and stamping a sheet metal. The rigidity and the strength of the outer fixing frame 20, the inner fixing frame 50 and the linkage frame 70 which are made by bending and stamping the sheet metal parts are ensured, the furniture is not easy to damage or break, and the service life and the use stability of the furniture are further effectively ensured. The external fixation frame 20 comprises an external fixation plate 21, two ends of the external fixation plate 21 are respectively provided with a bending fixation part 22, the bending fixation part 22 is provided with a fixation hole 23 connected and fixed with the external support 10, the middle part of the external fixation plate 21 is provided with two external punching blocks 24 which are distributed side by side and extend inwards, and the external punching blocks 24 are provided with hinge holes 25. The inner fixing frame 50 comprises an inner fixing plate 51, upper and lower

inner punching blocks

52 and 53 extending outwards are arranged on the inner fixing plate 51, each inner punching block at least comprises two inner punching blocks distributed side by side, and a hinge hole 54 is formed in each inner punching block. The linkage frame 70 comprises a linkage plate 71, two ends of the linkage plate 71 are respectively provided with a bending linkage block 72, an upper linkage hinge hole 73 and a lower linkage hinge hole 73 are arranged on the bending linkage block 72, a lower linkage shaft 80 is rotatably connected in the lower linkage hinge hole 73, and an upper linkage shaft 412 is rotatably connected in the upper linkage hinge hole 73.

As shown in fig. 3 to 8, the left folding assembly 30 includes a left lower folding arm 32 and a working platform 31 located above the left lower folding arm 32, the left ends of the working platform 31 and the left lower folding arm 32 are respectively hinged to the upper portion and the lower portion of the external fixing frame 20, the right end of the left lower folding arm 32 is hinged to the lower portion of the linkage frame 70 through a lower linkage shaft 80, the middle bottom of the working platform 31 is hinged to the upper portion of the linkage frame 70 through an upper linkage shaft 412, and the right end of the working platform 31 extends out of the linkage frame 70 to above the right folding assembly 40. The right folding assembly 40 includes an upper right folding arm 41 and a lower right folding arm 42, left ends of the upper right folding arm 41 and the lower right folding arm 42 are respectively hinged to upper and lower portions of the linkage frame 70 through an upper linkage shaft 412 and a lower linkage shaft 80, and right ends of the upper right folding arm 41 and the lower right folding arm 42 are respectively hinged to upper and lower portions of the internal fixing frame 50. The reinforcing component 60 comprises two reinforcing arms 61 which are hinged with each other, the outer end portions of the two reinforcing arms 61 are hinged with the left lower folding arm 32 and the right lower folding arm 42 respectively, the reinforcing component 60 formed by the mutual hinging of the two reinforcing arms 61 is arranged below the end portion, hinged with each other, of the left lower folding arm 32 and the right lower folding arm 42, the two reinforcing arms 61 are hinged through a first reinforcing hinge shaft 62, the outer end portions of the two reinforcing arms 61 are hinged through second reinforcing

hinge shafts

63 and 64 respectively, and the hinged reinforcing component 60, the left lower folding arm 32, the right lower folding arm 42 and the lower linkage shaft 80 form a movable diamond structure together. The arrangement of the reinforcing component 60 and the lower folding arm are combined together to form a diamond structure, so that the problem that the worktable 31 surface shakes or deviates in the unfolding or folding process is effectively avoided, and the stability of the worktable 31 surface in the unfolding or folding process is further ensured. Two ends of the upper linkage shaft 412 are respectively welded on the side plates of the right upper folding arm 41, a second linkage gear 411 is welded in the middle of the upper linkage shaft 412, and the second linkage gear 411 and the right upper folding arm 41 rotate along the linkage frame 70 along with the upper linkage shaft 412; the bottom welding has the first linkage gear 311 who is connected with the meshing of second linkage gear 411 in the middle of workstation 31, two and workstation 31 vertically punching press boards are stamped downwards in the middle of workstation 31, have first linkage gear 311 through the fixed axle welding between two punching press boards. When the folding workbench 31 is opened or closed, the first linkage gear 311 fixed at the bottom of the workbench 31 generates circular arc change along with the movement of the workbench 31, and then drives the second linkage gear 411 connected with the same in meshing to rotate in the same radian but opposite direction, so that the friction force of the left folding component 30 and the right folding component 40 in the operation process is effectively increased, the stability of the workbench 31 in the unfolding or folding process is effectively ensured, meanwhile, the sliding or unfolding opening caused by the overweight of the workbench 31 is effectively prevented, and the stability and reliability of the workbench 31 after folding are ensured. The upper linkage shaft 412 is sleeved with two speed reducing springs 413, the two speed reducing springs 413 are respectively positioned between the second linkage gears 411 on the two sides of the second linkage gears 411 and the side plates of the upper right folding arm 41, adjusting nuts 414 are further arranged between the speed reducing springs 413 and the side plates of the upper right folding arm 41, and threads corresponding to the adjusting nuts 414 are respectively arranged at the two ends of the upper linkage shaft 412. The arrangement of the speed reducing spring 413 releases forces in opposite directions to the second linkage gear 411 at two sides of the second linkage gear 411 respectively, so that the friction force of the second linkage gear 411 is further increased, the unfolding and folding processes of the workbench 31 are ensured to be stable, and the arrangement of the adjusting nut 414 is used for tightening or loosening the pressure intensity of the speed reducing spring 413.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner; the present invention may be readily implemented by those of ordinary skill in the art as illustrated in the accompanying drawings and described above; however, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention; meanwhile, any changes, modifications, and evolutions of the equivalent changes of the above embodiments according to the actual techniques of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. The utility model provides a general folding leg of furniture which characterized in that: the foldable furniture comprises a left folding component and a right folding component which are of parallelogram structures, an inner fixing frame which is arranged on the furniture and used for hinging the right folding component, an outer supporting piece which is positioned at the outer end of the left folding component and used for supporting, an outer fixing frame which is arranged at the upper part of the outer supporting piece and used for hinging the left folding component, a linkage frame which is positioned between the left folding component and the right folding component and used for linking and connecting the left folding component and the right folding component, and a reinforcing component which is positioned below the left folding component and the right folding component and respectively hinged with the left folding component and the right folding component, wherein the reinforcing component is hinged with the left folding component and the right folding component to form a movable diamond structure; the upper linkage shaft is sleeved with two speed reducing springs, the two speed reducing springs are respectively positioned between the second linkage gears on the two sides of the second linkage gears and the side plates of the upper right folding arm, and adjusting nuts are further arranged between the speed reducing springs and the side plates of the upper right folding arm.

2. The universal furniture folding leg according to claim 1, characterized in that: folding assembly includes folding arm under a left side and is located the workstation of folding arm top under the left side, the left end of folding arm is articulated with the upper portion and the lower part of outer mount respectively under workstation and the left side, the right-hand member of folding arm is articulated with the link frame lower part through linkage shaft down under a left side, the middle bottom of workstation is articulated through the upper portion of last linkage shaft with the link frame, the right-hand member of workstation stretches out the top of link frame to folding assembly on the right side.

3. The universal furniture folding leg according to claim 1, characterized in that: the right folding assembly comprises an upper right folding arm and a lower right folding arm, the left ends of the upper right folding arm and the lower right folding arm are hinged to the upper portion and the lower portion of the linkage frame through an upper linkage shaft and a lower linkage shaft respectively, and the right ends of the upper right folding arm and the lower right folding arm are hinged to the upper portion and the lower portion of the inner fixing frame respectively.

4. The universal furniture folding leg according to claim 1, characterized in that: the reinforcing component comprises two reinforcing arms which are hinged with each other, the outer end parts of the two reinforcing arms are hinged with the left lower folding arm and the right lower folding arm respectively, and the reinforcing component after the hinging is completed forms a movable diamond structure together with the left lower folding arm, the right lower folding arm and the lower linkage shaft.

5. The furniture utility folding leg according to any one of claims 1 to 4, characterized in that: the outer fixing frame, the inner fixing frame and the linkage frame are formed by bending and stamping metal plates.

6. The furniture universal folding leg according to claim 5, characterized in that: the outer fixing frame comprises an outer fixing plate, bending fixing parts are arranged at two ends of the outer fixing plate respectively, fixing holes fixedly connected with an outer supporting piece are formed in the bending fixing parts, two outer punching blocks which are distributed side by side and extend inwards are arranged in the middle of the outer fixing plate, and hinge holes are formed in the outer punching blocks.

7. The furniture universal folding leg according to claim 6, characterized in that: the internal fixation frame comprises an internal fixation plate, upper and lower layers of internal punching blocks extending outwards are arranged on the internal fixation plate, each layer of internal punching blocks at least comprises two internal punching blocks distributed side by side, and hinge holes are formed in the internal punching blocks.

8. The furniture universal folding leg according to claim 7, characterized in that: the linkage frame comprises a linkage plate, two ends of the linkage plate are respectively provided with a bending linkage block, an upper linkage hinge hole and a lower linkage hinge hole are arranged on the bending linkage block, a lower linkage shaft is rotationally connected in the lower linkage hinge hole, and an upper linkage shaft is rotationally connected in the upper linkage hinge hole.

9. The universal furniture folding leg according to claim 2, characterized in that: two ends of the upper linkage shaft are respectively welded on a side plate of the upper right folding arm, a second linkage gear is welded in the middle of the upper linkage shaft, and the second linkage gear and the upper right folding arm rotate along the linkage frame along with the upper linkage shaft; and a first linkage gear in meshed connection with the second linkage gear is welded at the bottom of the middle of the workbench.