CN108827244B

CN108827244B - Level ruler

Info

Publication number: CN108827244B
Application number: CN201810754111.XA
Authority: CN
Inventors: 吴东明
Original assignee: Zhejiang East Precision Measuring Tools Co ltd
Current assignee: Zhejiang East Precision Measuring Tools Co ltd
Priority date: 2018-07-11
Filing date: 2018-07-11
Publication date: 2023-05-30
Anticipated expiration: 2038-07-11
Also published as: CN108827244A

Abstract

The invention provides a level bar, which comprises a bar body and a horizontal level bubble component, wherein the bar body is a hollow square tube, the side surface of the bar body is provided with a mounting groove, and the horizontal level bubble component is mounted in the mounting groove. The horizontal level bubble subassembly includes horizontal level bubble, connecting seat and horizontal level bubble seat, horizontal level bubble fixed mounting is on horizontal level bubble seat, the connecting seat includes the bedplate, the both sides of bedplate are around being equipped with the lateral wall all around, one side border middle part indent of bedplate forms the installation notch, horizontal level bubble seat installs in the installation notch, the both sides of installation notch form the top brace arm, be equipped with the top brace structure on the bedplate, the top brace structure makes the lateral wall to the bedplate outside deformation to the lateral wall application of force of keeping away from installation notch one side, and then make lateral wall and top brace arm jack up the inner chamber both sides of the ruler body respectively. The level bar can complete connection of the level bubble seat and the bar body without gluing, reduces assembly procedures and improves assembly efficiency.

Description

Level ruler

Technical Field

The invention relates to the field of measuring tools, in particular to a level bar.

Background

The level bar is a common measuring tool which is not separated in daily life of people and is commonly used for occasions such as building construction, mechanical installation, woodworking and the like. The level bar generally comprises a bar body, a vertical level bubble seat and a horizontal level bubble seat, wherein the level bubble seat is fixedly provided with a level bubble, and the level bubble seat is fixedly connected with the bar body. In the general production process, the bubble level seat is fixedly connected with the ruler body in an adhesive mode, then the bubble level is arranged in the bubble level seat, the position of the bubble level is adjusted, and finally the bubble level is fixed in an adhesive mode, so that the assembly operation is completed. The following problems are mainly existed in the production mode: firstly, the assembly process requires two gluing processes, and the gluing process has a curing period, which is not beneficial to the realization of automatic production; secondly, through the fixed bubble of viscose, produce irregular deformation at glue solidification process, make the bubble precision change, and then influence product precision. Thirdly, because of the curing period of the glue, the production period is longer, and the process of the finished product on the assembly line on the ruler body can not be realized, thereby influencing the efficiency.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the level bar, which can complete the connection of the level bubble seat and the bar body without gluing, reduces the assembly process and improves the assembly efficiency.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a level bar comprises a bar body and a horizontal level bubble component, wherein the bar body is a hollow square tube, an installation groove is formed in the side face of the bar body, and the horizontal level bubble component is installed in the installation groove. The horizontal level bubble subassembly includes horizontal level bubble, connecting seat and horizontal level bubble seat, horizontal level bubble fixed mounting is on horizontal level bubble seat, the connecting seat includes the bedplate, the both sides of bedplate are around being equipped with the lateral wall all around, one side border middle part indent of bedplate forms the installation notch, horizontal level bubble seat installs in the installation notch, the both sides of installation notch form the top brace arm, be equipped with the top brace structure on the bedplate, the top brace structure makes the lateral wall to the bedplate outside deformation to the lateral wall application of force of keeping away from installation notch one side, and then make lateral wall and top brace arm jack up the inner chamber both sides of the ruler body respectively.

During assembly, the connecting seat is arranged in the mounting groove of the level bar, at the moment, the connecting seat and the level bar form loose fit, the supporting structure is utilized to apply force to the side wall to enable the side wall to deform towards the outer side of the seat board, the side wall outwards deforms to enable the size of the connecting seat to be enlarged, and the side wall of the connecting seat and the supporting arms are tightly supported on two side faces of the inner cavity of the level bar, so that fixed connection is completed.

Further, the propping structure comprises a propping piece and a propping bulge, the propping bulge is arranged on one side of the middle part of the seat plate, which is far away from the installation notch, and the propping piece is in telescopic connection with the propping bulge, and one end of the propping piece is propped against the side wall. The adoption of the jacking structure is low in cost and easy to realize.

Further, the horizontal level bubble seat comprises a bottom plate and two vertical plates, the two vertical plates are respectively arranged at two ends of the bottom plate to form a level bubble installation cavity, an adjusting lug is arranged on one side, opposite to the level bubble installation cavity, of at least one vertical plate, a fixed connection structure is arranged between one side, opposite to the level bubble installation cavity, of the bottom plate and the bottom of the installation notch, and a telescopic adjusting structure is arranged between the adjusting lug and the connection seat. The bottom of the horizontal bubble seat is fixedly connected with the connecting seat, and the position of the horizontal bubble seat relative to the connecting seat is adjusted by utilizing the adjusting lugs, so that the precision adjustment of the horizontal bubble can be realized.

Further, the fixed connection structure still includes fixed draw-in groove and first connection arch, and fixed draw-in groove sets up the tank bottom at the installation notch, and first connection arch sets up in the bottom plate one side middle part of bubble installation cavity dorsad, and first connection arch cartridge is in fixed draw-in groove, and the tank bottom of installation notch is equipped with elastic bulge, and the bottom plate still is equipped with the extrusion arch in the face of the one end of installation notch, extrudees protruding and elastic bulge and supports and lean on. The fixed connection structure is simple in structure and convenient to assemble, and the gap during adjustment can be eliminated due to the arrangement of the extrusion protrusions and the elastic protrusions.

Further, the telescopic adjusting structure comprises a horizontal adjusting protrusion and a horizontal adjusting piece, the horizontal adjusting protrusion is arranged on the connecting seat, and two ends of the horizontal adjusting piece are respectively connected with the adjusting lug and the horizontal adjusting protrusion in a telescopic manner. The adjusting structure is low in cost and easy to realize.

Further, the inner chamber both sides of the chi body are equipped with first cooperation draw-in groove and second cooperation draw-in groove respectively, and the side wall outside protruding one side of keeping away from the installation notch in bedplate middle part forms first cooperation boss, and the tip of top brace arm is equipped with the second cooperation boss, and first cooperation boss clamps in first cooperation draw-in groove, and the second cooperation boss clamps in the second cooperation draw-in groove. The setting of cooperation draw-in groove and cooperation boss can improve the installation accuracy and the installation strength of bubble seat connecting seat in the chi body.

Further, the level bar still includes the vertical level bubble subassembly, the tip of the chi body is equipped with the installing port, the vertical level bubble subassembly is installed in the installing port, the vertical level bubble subassembly includes the vertical level bubble, vertical level bubble seat and end plug, vertical level bubble fixed mounting is on the vertical level bubble seat, be equipped with the second between the one end of end plug and the vertical level bubble seat and connect the arch, the one end that the vertical level bubble seat was kept away from to the end plug is equipped with end plug backup plate and third cooperation boss, the end plug backup plate sets up the tip at the end plug, one side that the third cooperation boss was backed to the end plug backup plate is the inclined plane, the cooperation of third cooperation boss and the inner chamber of the chi body, the end plug backup plate is leaned on with the terminal surface subsides of the chi body. During assembly, the vertical level bubble seat is plugged into the mounting opening of the ruler body, and the end plug and the level bubble seat are determined through the limiting of the end plug backup plate and the matching boss.

Further, the level bar further comprises a locating pin, a first locating pin hole is formed in the bar body, a hanging hole is formed in the end plug, a second locating pin hole is formed in the middle of the hanging hole, and the locating pin is plugged into the first locating pin hole and the second locating pin hole. By adopting the structure, the mounting precision of the end plug, the vertical level bubble seat and the ruler body can be further improved.

Further, deformation protrusions and vertical adjusting parts are further arranged between the end plugs and the vertical level bubble seats, the second connection protrusions are arranged in the middle of the end plugs and the vertical level bubble seats, the deformation protrusions are arranged on one sides of the end plugs and the vertical level bubble seats, two ends of the vertical adjusting parts are respectively connected with the end plugs and the vertical level bubble seats in a telescopic mode, and the deformation protrusions are deformed or recovered to deform when the vertical adjusting parts are adjusted. After the end plug determines the position of the vertical level bubble seat in the ruler body, the level bubble is adjusted in place through the adjustment of the adjusting piece, the elastic action of the adjusting deformation bulge is adjusted to eliminate the adjusting gap, and the adjusting precision of the level bubble is ensured.

Further, the vertical level bubble assembly further comprises an end cover and a fixed cover, an adjusting hole is formed in the end plug, the vertical adjusting piece is installed in the adjusting hole, a containing groove is formed in one end of the end cover, an installation through hole is formed in the containing groove, a fixed column is arranged on one side of the fixed cover and penetrates through the installation through hole to be connected with the adjusting hole in an interference fit mode, the fixed cover is clamped in the containing groove, and the end cover and the end plug are tightly propped up by the fixed cover. The end cover and the fixed cover are in a split structure, so that the end cover can be made of soft materials to ensure the anti-falling performance of the level bar, meanwhile, the fixed cover is made of hard materials, and the end cover and the end plug are firmly fixed by the fixed cover to ensure the connection strength.

In summary, the level bar can complete connection of the level bubble seat and the bar body without gluing, reduces assembly procedures and improves assembly efficiency.

Drawings

FIG. 1 is a schematic view of the structure of the level bar of the present embodiment;

FIG. 2 is a schematic elevational view of the horizontal vial assembly of the level of the present embodiment;

FIG. 3 is a schematic elevational view of the horizontal bubble seat of the level of the present embodiment;

FIG. 4 is a schematic elevational view of the vertical vial assembly of the level of the present embodiment;

FIG. 5 is a schematic right side view of the vertical vial assembly of the level of the present embodiment;

FIG. 6 is a schematic view of the right side view of the vertical vial assembly of the level of the present embodiment without the fixed cover attached;

FIG. 7 is a schematic view of the structure of the stationary cover in the vertical vial assembly of the level of the present embodiment;

the ruler body-1, the first matching clamping groove-11, the second matching clamping groove-12, the first positioning pin hole-13, the horizontal level bubble component-2, the horizontal level bubble-21, the horizontal level bubble seat-22, the bottom plate-221, the vertical plate-222, the adjusting lug-223, the first connecting protrusion-224, the connecting seat-23, the seat plate-231, the side wall-232, the first matching lug-232 a, the second matching lug-232 b, the mounting notch-233, the top supporting arm-234, the top supporting protrusion-235, the fixing clamping groove-236, the horizontal adjusting protrusion-237, the horizontal adjusting piece-238, the top supporting piece-24, the vertical level bubble component-3, the vertical level bubble-31, the vertical level bubble seat-32, the vertical adjusting protrusion-321, the end plug-33, the end plug plate-331, the third matching lug-332, the hanging hole-333, the second positioning pin hole-334, the second connecting protrusion-34, the deformation protrusion-35, the vertical adjusting piece-36, the end cover-37, the containing groove-372, the through hole-372, the mounting hole-381, the fixing post-4 and the fixing post-381.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

As shown in fig. 1, the horizontal ruler comprises a ruler body 1 and a horizontal bubble assembly 2, wherein the ruler body 1 is a hollow square tube, an installation groove is formed in the side face of the ruler body 1, and the horizontal bubble assembly 2 is installed in the installation groove. The horizontal level bubble assembly 2 comprises a horizontal level bubble 21, a horizontal level bubble seat 22 and a connecting seat 23, wherein the horizontal level bubble 21 is fixedly installed on the horizontal level bubble seat 22, the connecting seat 23 comprises a seat plate 231, side walls 232 are arranged around two sides of the seat plate 231, an installation notch 233 is formed by inwards concave parts of the middle part of one side edge of the seat plate 231, the horizontal level bubble seat 22 is installed in the installation notch 233, supporting arms 234 are formed on two sides of the installation notch 233, a supporting structure is arranged on the seat plate 231, and the supporting structure exerts force on the side walls 232 far away from the side of the installation notch 233 to enable the side walls 232 to deform outwards of the seat plate 231, so that the side walls 232 and the supporting arms 234 respectively support two sides of an inner cavity of the ruler body 1.

During assembly, the connecting seat 23 is arranged in the mounting groove of the ruler body 1, at the moment, the connecting seat 23 and the ruler body 1 form loose fit, the supporting structure is utilized to apply force to the side wall 232 to enable the side wall 232 to deform towards the outer side of the seat plate 231, the side wall 232 deforms outwards to enable the size of the connecting seat 23 to be enlarged, and the side wall 232 and the supporting arms 234 of the connecting seat 23 are tightly supported against two side faces of the inner cavity of the ruler body 1, so that fixed connection is completed.

Specifically, the propping structure includes a propping member 24 and a propping protrusion 235, the propping protrusion 235 is disposed at one side of the middle part of the seat plate 231 far away from the installation notch 233, the propping member 24 is in telescopic connection with the propping protrusion 235, and one end of the propping member 24 is propped against the side wall 232. The adoption of the jacking structure is low in cost and easy to realize.

As shown in fig. 3, the horizontal vial seat 22 includes a bottom plate 221 and two vertical plates 222, the two vertical plates 222 are respectively disposed at two ends of the bottom plate 221 to form a vial installation cavity, an adjusting lug 223 is disposed on a side of at least one vertical plate 222 facing away from the vial installation cavity, a fixed connection structure is disposed between a side of the bottom plate 221 facing away from the vial installation cavity and a bottom of the installation slot 233, and a telescopic adjustment structure is disposed between the adjusting lug 223 and the connection seat 23. The bottom of the horizontal bubble seat 22 is fixedly connected with the connecting seat 23, and the position of the horizontal bubble 22 seat relative to the connecting seat 23 is adjusted by utilizing the adjusting lug 223, so that the precision adjustment of the horizontal bubble 21 can be realized.

Specifically, the fixed connection structure further includes a fixing clamping groove 236 and a first connection protrusion 224, the fixing clamping groove 236 is disposed at a groove bottom of the mounting groove 233, the first connection protrusion 224 is disposed at a middle portion of one side of the bottom plate 221 opposite to the vial mounting cavity, the first connection protrusion 224 is inserted into the fixing clamping groove 236, an elastic protrusion 233a is disposed at a groove bottom of the mounting groove 233, an extrusion protrusion 221a is disposed at one end of the bottom plate 221 opposite to the mounting groove 233, and the extrusion protrusion 221a abuts against the elastic protrusion 233 a. Such a fixed connection structure is simple in structure and easy to assemble, and the arrangement of the pressing protrusions 221a and the elastic protrusions 233a can eliminate the gap at the time of adjustment.

In addition, the telescopic adjusting structure comprises a horizontal adjusting protrusion 237 and a horizontal adjusting piece 238, wherein the horizontal adjusting protrusion 237 is arranged on the connecting seat 23, and two ends of the horizontal adjusting piece 238 are respectively connected with the adjusting lug 223 and the horizontal adjusting protrusion 237 in a telescopic manner. The adjusting structure is low in cost and easy to realize. In this embodiment, the horizontal adjustment member 238 is a screw that is in threaded engagement with the horizontal adjustment protrusion 237 and the adjustment lug 223 to achieve a telescopic connection.

Preferably, as shown in fig. 1, two sides of the inner cavity of the rule body 1 are respectively provided with a first matching clamping groove 11 and a second matching clamping groove 12, a side wall 232 of one side of the middle part of the seat plate 231 far away from the mounting notch 233 is outwards protruded to form a first matching boss 232a, the end part of the top supporting arm 234 is provided with a second matching boss 232b, the first matching boss 232a is arranged in the first matching clamping groove 11, and the second matching boss 232b is clamped in the second matching clamping groove 12. The arrangement of the matching clamping groove and the matching boss can improve the installation accuracy and the installation strength of the connecting seat 23 in the ruler body 1.

As shown in fig. 1 and 4, the level further includes a vertical level vial assembly 3, the end of the gauge body 1 is provided with a mounting opening, the vertical level vial assembly 3 is mounted in the mounting opening, the vertical level vial assembly 3 includes a vertical level vial 31, a vertical level vial seat 32 and an end plug 33, the vertical level vial 31 is fixedly mounted on the vertical level vial seat 32, a second connection protrusion 34 is disposed between one end of the end plug 33 and the vertical level vial seat 32, one end of the end plug 33, which is far away from the vertical level vial seat 32, is provided with an end plug backup plate 331 and a third fitting boss 332, the end plug backup plate 331 is disposed at the end of the end plug 33, one side of the third fitting boss 332 facing away from the end plug backup plate 331 is an inclined plane, the third fitting boss 332 is fitted with the inner cavity of the gauge body 1, and the end plug backup plate 331 is abutted against the end face of the gauge body 1. During assembly, the vertical level bubble seat 32 is plugged into the mounting hole of the ruler body 1, and the positions of the end plug 33 and the level bubble seat 32 are determined through the limit of the end plug backup plate 331 and the third matching boss 332.

As shown in fig. 1, the level ruler further comprises a positioning pin 4, a first positioning pin hole 13 is formed in the ruler body 1, a hanging hole 333 is formed in the end plug 33, a second positioning pin hole 334 is formed in the middle of the hanging hole 333, and the positioning pin 4 is plugged into the first positioning pin hole 13 and the second positioning pin hole 334. With this structure, the accuracy of mounting the end plug 33 and the vertical level vial holder 32 to the scale body 1 can be further improved.

As shown in fig. 1 and 4, a deformation protrusion 35 and a vertical adjustment member 36 are further disposed between the end plug 33 and the vertical bubble seat 32, the second connection protrusion 34 is disposed in the middle of the end plug 33 and the vertical bubble seat 32, the deformation protrusion 35 is disposed on one side of the end plug 33 and the vertical bubble seat 32, two ends of the vertical adjustment member 36 are respectively connected with the end plug 33 and the vertical bubble seat 32 in a telescopic manner, and the vertical adjustment member 36 adjusts the deformation protrusion 35 to deform or recover deformation. After the end plug 33 determines the position of the vertical vial seat 32 in the scale body 1, the horizontal vial 31 is adjusted in place by adjustment of the adjusting member 36, and the elastic action of the adjusting deformation protrusion 35 eliminates the adjustment gap, so as to ensure the adjustment accuracy of the vial. In this embodiment, the vertical adjustment member 36 is a screw, and the vertical bubble seat 32 is provided with a vertical adjustment protrusion 321, and the screw is screwed with the vertical adjustment protrusion 321 and the end plug 33 to achieve telescopic connection.

As shown in fig. 4, 5, 6 and 7, the vertical level bubble assembly 3 further includes an end cover 37 and a fixing cover 38, an adjusting hole is formed in the end cover 37, the vertical adjusting piece 36 is installed in the adjusting hole, a containing groove 371 is formed in one end of the end cover 37, an installation through hole 372 is formed in the containing groove 371, a fixing column 381 is formed on one side of the fixing cover 38, the fixing column 381 penetrates through the installation through hole 372 to be connected with the adjusting hole in an interference fit mode, the fixing cover 38 is clamped in the containing groove 371, and the fixing cover 38 tightly pushes the end cover 37 against the end plug 33. The end cover 37 and the fixed cover 38 are in a split structure, so that the end cover 37 can be made of soft materials to ensure the anti-falling performance of the level, meanwhile, the fixed cover is made of hard materials, and the end cover 37 and the end plug 33 are firmly fixed by the fixed cover 38 to ensure the connection strength.

In summary, the level bar can complete the connection between the level bubble seat and the bar body 1 without gluing, thereby reducing the assembly process and improving the assembly efficiency.

In summary, the foregoing description is only of the preferred embodiments of the invention, and is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims

1. A level bar, characterized in that: the square tube type leveling instrument comprises a square body and a horizontal level bubble assembly, wherein the square body is a hollow square tube, an installation groove is formed in the side face of the square body, and the horizontal level bubble assembly is installed in the installation groove;

the horizontal level bubble assembly comprises a horizontal level bubble, a connecting seat and a horizontal level bubble seat, wherein the horizontal level bubble is fixedly arranged on the horizontal level bubble seat, the connecting seat comprises a seat plate, side walls are arranged around two sides of the seat plate, the middle part of one side edge of the seat plate is concavely formed into an installation notch, the horizontal level bubble seat is arranged in the installation notch, top supporting arms are formed on two sides of the installation notch, a top supporting structure is arranged on the seat plate, and the top supporting structure applies force to the side wall far away from one side of the installation notch to deform the side wall outwards of the seat plate, so that the side wall and the top supporting arms respectively jack two sides of an inner cavity of the ruler body;

the horizontal level bubble seat comprises a bottom plate and two vertical plates, wherein the two vertical plates are respectively arranged at two ends of the bottom plate to form a level bubble installation cavity, one side of at least one vertical plate, which is opposite to the level bubble installation cavity, is provided with an adjusting lug, a fixed connection structure is arranged between one side of the bottom plate, which is opposite to the level bubble installation cavity, and the bottom of the installation notch, and a telescopic adjusting structure is arranged between the adjusting lug and the connection seat;

the fixed connection structure further comprises a fixed clamping groove and a first connection protrusion, the fixed clamping groove is arranged at the bottom of the installation notch, the first connection protrusion is arranged in the middle of one side of the bottom plate, which is opposite to the level bubble installation cavity, the first connection protrusion is inserted into the fixed clamping groove, an elastic protrusion is arranged at the bottom of the installation notch, an extrusion protrusion is further arranged at one end of the bottom plate, which is opposite to the installation notch, and the extrusion protrusion is abutted to the elastic protrusion;

the telescopic adjusting structure comprises a horizontal adjusting protrusion and a horizontal adjusting piece, the horizontal adjusting protrusion is arranged on the connecting seat, and two ends of the horizontal adjusting piece are respectively connected with the adjusting lug and the horizontal adjusting protrusion in a telescopic manner;

the end part of the ruler body is provided with a mounting opening, the vertical level bubble assembly is mounted in the mounting opening, the vertical level bubble assembly comprises a vertical level bubble, a vertical level bubble seat and an end plug, the vertical level bubble is fixedly mounted on the vertical level bubble seat, a second connecting protrusion is arranged between one end of the end plug and the vertical level bubble seat, one end of the end plug, which is far away from the vertical level bubble seat, is provided with an end plug backup plate and a third matching boss, the end plug backup plate is arranged at the end part of the end plug, one side, which is opposite to the end plug backup plate, of the third matching boss is an inclined plane, the third matching boss is matched with an inner cavity of the ruler body, and the end plug backup plate is abutted against the end face of the ruler body;

the vertical adjusting piece is characterized in that a deformation bulge and a vertical adjusting piece are further arranged between the end plug and the vertical level bubble seat, the second connection bulge is arranged in the middle of the end plug and the vertical level bubble seat, the deformation bulge is arranged on one side of the end plug and one side of the vertical level bubble seat, two ends of the vertical adjusting piece are respectively connected with the end plug and the vertical level bubble seat in a telescopic mode, and the deformation bulge is adjusted to deform or recover deformation by the vertical adjusting piece.

2. A level bar according to claim 1, wherein: the supporting structure comprises a supporting piece and supporting protrusions, the supporting protrusions are arranged on one side, far away from the installation notch, of the middle portion of the seat plate, the supporting piece is connected with the supporting protrusions in a telescopic mode, and one end of the supporting piece abuts against the side wall in a supporting mode.

3. A level bar according to claim 1, wherein: the inner chamber both sides of the chi body are equipped with first cooperation draw-in groove and second cooperation draw-in groove respectively, the side wall outside protruding one side of keeping away from the installation notch in bedplate middle part forms first cooperation boss, the tip of top support arm is equipped with the second cooperation boss, first cooperation boss clamps in first cooperation draw-in groove, the second cooperation boss clamps in the second cooperation draw-in groove.

4. A level bar according to claim 1, wherein: still include the locating pin, be equipped with first location pinhole on the chi body, be equipped with the hanging hole on the end plug, the middle part of hanging hole is equipped with the second location pinhole, the locating pin stopper dress is in first location pinhole and second location pinhole.

5. A level bar according to claim 1, wherein: the vertical level bubble assembly further comprises an end cover and a fixed cover, an adjusting hole is formed in the end plug, the vertical adjusting piece is installed in the adjusting hole, a containing groove is formed in one end of the end cover, an installation through hole is formed in the containing groove, one side of the fixed cover is provided with a fixed column, the fixed column penetrates through the installation through hole to be connected with the adjusting hole in an interference fit mode, the fixed cover is embedded in the containing groove in a clamping mode, and the end cover is tightly propped against the end plug by the fixed cover.