CN216264268U

CN216264268U - Shield constructs machine knife case welding auxiliary positioning device

Info

Publication number: CN216264268U
Application number: CN202122396247.8U
Authority: CN
Inventors: 杜国正; 于普涟; 刘国威
Original assignee: Jinan Heavy Industry Group Co ltd
Current assignee: Jinan Heavy Industry Group Co ltd
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2022-04-12
Anticipated expiration: 2031-09-30

Abstract

The utility model discloses a shield machine tool box welding auxiliary positioning device, which mainly comprises two parts: the cutter head centering device and the cutter box welding auxiliary positioning device; the cutter head centering device comprises a double-hole positioning base, a single-hole supporting base, an L-shaped auxiliary circular tube and an auxiliary positioning rope; the auxiliary positioning device for the cutter box welding comprises a rack, a centering mechanism, a suspension arm support, a suspension arm rotating body, a suspension arm rod piece, a pull ring, a pull rope, a suspension arm connecting plate and a movable positioning device, wherein the rack is arranged on the plane of a cutter head panel. The utility model can realize the quick centering of the cutter head of the shield machine, realize the welding and positioning of the cutter boxes at different inclination angles, and improve the working efficiency on the premise of ensuring the positioning precision.

Description

Shield constructs machine knife case welding auxiliary positioning device

Technical Field

The utility model relates to an auxiliary positioning device for welding of a cutter box of a shield tunneling machine, and belongs to the technical field of shield tunneling machines.

Background

The cutter head of the shield machine is one of key components of the shield machine, wherein errors often exist between an actual movement track and a theoretical movement track of a cutter after welding of the shield machine cutter, and when the errors are large, the service life, the cutting effect, the tunneling speed and the construction efficiency of the cutter head of the shield machine can be seriously influenced. The main cutting knives such as the hobbing cutter, the tooth knife and the like are seriously worn in the tunneling process of the shield tunneling machine and need to be frequently changed, so that the main cutting knives such as the hobbing cutter, the tooth knife and the like cannot be assembled in a direct welding mode, but need to be assembled by means of the bolt connection with the aid of the knife box welded on the cutter head, and the main cutting knives which are seriously worn in the tunneling process are conveniently changed; therefore, the accuracy of the welding position of the tool box directly determines whether the motion track of the relevant tool is accurate. The cutter head structure of the large-diameter shield machine is large in size, is generally assembled and welded in a partitioning mode, is affected by factors such as manufacturing errors and welding deformation in the process, the actual position size of a welding opening of a cutter head reserved on the cutter head structure often deviates from a theoretical design position, and if the position of the welding opening of the welded cutter head is not inspected and error correction is not carried out, the overall tunneling effect of the cutter head is seriously affected. Therefore, the shield machine tool box auxiliary welding positioning device is provided, and the problems that the cutter head is rapidly centered and the welding precision of the tool box is improved are urgently needed to be solved by technical personnel in the field.

Disclosure of Invention

The utility model mainly aims at the problems of insufficient welding positioning precision and large welding error of the existing shield machine tool box, and provides an auxiliary positioning device for the shield machine tool box welding, so that the rapid centering of a shield cutter head and the high-precision welding of the shield machine tool box are realized.

In order to solve the technical problem, the utility model provides an auxiliary positioning device for welding a shield machine tool box, which mainly comprises two parts: the cutter head centering device and the cutter box welding auxiliary positioning device; the cutter centering device comprises a double-hole positioning base, a single-hole supporting base, an L-shaped auxiliary circular tube and a positioning auxiliary rope, wherein the single-hole supporting base and the double-hole positioning base are placed around the welded cutter, the L-shaped auxiliary circular tube sequentially penetrates through holes in the base, the L-shaped auxiliary circular tube is tangent to the outer diameter of the cutter, the positioning auxiliary rope is scribed along the positioning auxiliary rope for multiple times in a region of the cutter close to the center of a circle, and the center of a dense cross point region is used as a positioning reference of the center of the cutter; the auxiliary positioning device for the cutter box welding comprises a rack, a centering mechanism, a suspension arm support, a suspension arm rotating body, a suspension arm rod piece, a pull ring, a pull rope, a suspension arm connecting plate and a movable positioning device, wherein the rack is arranged on the plane of a cutter head panel.

Two double-hole positioning bases of the cutter head centering device are arranged on a diagonal line, the double-hole positioning bases are provided with two vertically crossed through holes, the top of each double-hole positioning base is provided with an outer extension rod, and the middle points of the central lines of the two staggered and crossed holes are collinear with the axis of the outer extension rod; the L-shaped auxiliary circular tube sequentially penetrates through the opening in the base and is tangent to the outer diameter of the cutter head; the top end of the outward extending rod is provided with a through hole, and the positioning auxiliary line passes through the through hole; the single-hole supporting base is provided with a single through hole, the height of the through hole is equal to the height of a certain hole in the double-hole positioning base, and the two same L-shaped auxiliary circular tubes penetrate through the through hole of the single-hole supporting base and are tangent to the outer circumference of the cutter head, so that the lines can be drawn along the positioning auxiliary ropes in the area of the cutter head close to the circle center.

A square positioning frame is reserved in the center of a rack of the auxiliary positioning device for welding the cutter box, and the circle center of an inscribed circle of the square positioning frame is superposed with the circle center of an inscribed circle of the rack; the centering mechanism is fixed on a square positioning frame of the rack through bolts; the suspension arm support is installed at the top end of the rack, four support legs which are ninety degrees mutually are arranged in the middle of the suspension arm support, a fixed platform is arranged below the suspension arm support, a first electromagnetic brake is fixed on the platform, a cylindrical stepped shaft is arranged above the first electromagnetic brake and provided with a counter bore, a bearing is installed in the counter bore, and a suspension arm rotating body is installed on the suspension arm support through an inner bearing of the counter bore; an external extending shaft is arranged below the suspension arm rotating body, a key groove is formed in the external extending shaft, a weight box is arranged on one side of the external extending shaft, a cantilever mounting fixed support is arranged on the other side of the external extending shaft, and a suspension arm rod piece is connected with the suspension arm rotating body through the cantilever mounting fixed support; the pull ring is arranged at the top end of the suspension arm rotating body and the upper side of the suspension arm and is connected with the suspension arm rotating body and the suspension arm rotating body through a pull rope, and the weight box and the pull ring jointly maintain the balance of the suspension arm rod piece; a size distance mark is arranged on the vertical plane of the suspension arm rod piece and is connected with the cantilever installation fixed support through a bolt; the suspension arm connecting plate is arranged at the joint of the two suspension arms and is connected with the suspension arms through bolts; the movable positioning device is fastened on the boom rod piece.

The aligning mechanism comprises a screw rod and a support piece, and the tail end of the screw rod is a conical tip and is coaxial with the suspension arm rotating body.

The movable positioning device comprises a fixing plate, a fixing bolt, a second electromagnetic brake, a rotatable scale, a vertical telescopic sleeve ruler and a transverse telescopic sleeve ruler, and the auxiliary positioning device for the knife box welding is fastened on the suspension arm rod piece through the fixing plate and the fixing bolt; the upper part and the lower part of the symmetrical center line are respectively provided with a sharp tooth so as to determine the size position of the movable positioning device relative to the positioning reference of the center of the cutter head circle; the second electromagnetic brake is arranged on the fixing plate on one side, and the upper surface of the second electromagnetic brake is attached with a circular angle scale; a rotating shaft is arranged in an inner hole of the second electromagnetic brake and is connected with a rotatable scale, a straight notch is formed in the upper portion of the rotatable scale, angle scales on the upper surface of the second electromagnetic brake can be observed through the notch, and the distance from the two outer surfaces of the rotatable scale to the two inner surfaces of the fixing plate is equal.

The vertical telescopic sleeve ruler and the horizontal telescopic sleeve ruler consist of a strip-shaped inner graduated scale and a U-shaped outer graduated scale, and a fastening groove is formed in the center of each of the two telescopic sleeve rulers and can be fastened by bolts; the tail end of the vertical telescopic sleeve ruler is provided with a U-shaped groove, the groove width is equal to the thickness of the transverse strip-shaped inner dividing ruler, and the two transverse telescopic inner dividing rulers are symmetrical about the center line of the inner groove of the vertical telescopic sleeve ruler during assembly.

Has the advantages that: the utility model provides the auxiliary positioning device for the welding of the shield machine tool box according to the welding process flow of the shield machine tool box, which can realize the quick centering of the cutter head of the shield machine and the welding positioning of the tool box at different inclination angles, and greatly improves the working efficiency on the premise of ensuring the positioning precision.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of a cutterhead centering device of the present invention;

FIG. 3 is a schematic view of a single-hole support base according to the present invention;

FIG. 4 is a schematic structural view of a dual-hole positioning base according to the present invention;

FIG. 5 is a schematic structural view of an auxiliary positioning device for welding a knife box according to the present invention;

FIG. 6 is a schematic view of the structure of the frame of the present invention;

FIG. 7 is a schematic structural diagram of a boom support of the present invention;

FIG. 8 is a schematic structural view of the boom rotator of the present invention;

FIG. 9 is a schematic structural view of a boom rotating mechanism of the present invention;

FIG. 10 is a schematic structural view of a boom coupling plate of the present invention;

FIG. 11 is a schematic view of the assembled boom of the present invention;

FIG. 12 is a schematic structural view of the centering mechanism of the present invention;

FIG. 13 is a schematic view of a movable positioning device according to the present invention;

FIG. 14 is a schematic structural view of the retractable set of rules of the present invention;

FIG. 15 is a schematic view of a positioning plate of the movable positioning device of the present invention;

FIG. 16 is a schematic view of the installation of the auxiliary positioning frame and the centering mechanism for the welding of the knife box of the present invention.

In the figure: 1. a cutter head centering device; 2. the auxiliary positioning device for the knife box welding; 11. a dual-hole positioning base; 12. a single-hole support base; 13. an L-shaped auxiliary circular tube; 14. positioning an auxiliary rope; 21. a frame; 22. a centering mechanism; 23. a boom support; 24. a boom rotator; 25. a boom bar; 26. a pull ring; 27. pulling a rope; 28. a boom coupling plate; 29. a movable positioning device; 111. an outward extending rod; 221. a support member; 222. a screw rod; 231. supporting legs; 232. a first electromagnetic brake; 241. a weight box; 242. a keyway; 243. a cantilever is installed and fixed with a support; 291. a fixing plate; 292. fixing the bolt; 293. a second electromagnetic brake; 294. a rotatable scale; 295. a vertical telescopic ruler set; 296. a transversely telescopic ruler set.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples.

As shown in fig. 1-16, the utility model provides a shield machine tool box welding auxiliary positioning device, which comprises a tool pan centering device 1 and a tool box welding auxiliary positioning device 2, wherein the tool pan centering device 1 is used for determining the rotation center of a tool pan and further determining the motion track center of the shield machine tool box and a tool, and comprises a double-hole positioning base 11, a single-hole supporting base 12, an L-shaped auxiliary circular tube 13 and a positioning auxiliary rope 14, the single-hole supporting base 12 and the double-hole positioning base 11 are placed around a welding tool pan, the L-shaped auxiliary circular tube 13 sequentially penetrates through holes in the bases, the L-shaped auxiliary circular tube 13 is tightened to be tangent to the outer diameter of the tool pan, a line is drawn along the positioning auxiliary rope 14 in a near-circle center area of the tool pan for multiple times, and the center of an intensive cross point area is used as a tool pan circle center positioning reference; the auxiliary positioning device 2 for the cutter box welding comprises a frame 21, an alignment mechanism 22, a boom support 23, a boom rotator 24, a boom rod 25, a pull ring 26, a pull rope 27, a boom connecting plate 28 and a movable positioning device 29, wherein the frame 21 is arranged on the plane of a cutter head panel.

The two double-hole positioning bases 11 of the cutter head centering device 1 are arranged on a diagonal line, the double-hole positioning bases 11 are provided with two vertically crossed through holes for placing L-shaped auxiliary circular tubes, the top parts of the double-hole positioning bases are provided with outer extension rods 111, and the middle points of the central lines of the two staggered and crossed holes are collinear with the axes of the outer extension rods 111; the L-shaped auxiliary circular tube 13 sequentially penetrates through the opening in the base and is tangent to the outer diameter of the cutter head; the top end of the external extension rod 111 is provided with a through hole through which the positioning auxiliary line 14 passes; the single-hole supporting base 12 is provided with a single through hole, the height of the through hole is equal to the height of a certain hole in the double-hole positioning base 11, and two identical L-shaped auxiliary circular tubes 13 penetrate through the through hole of the single-hole supporting base 12 and are tangent to the outer circumference of the cutter head, so that a line can be drawn along the positioning auxiliary rope 14 in the area of the cutter head close to the center of a circle.

A square positioning frame is reserved in the center of the rack 21 of the auxiliary positioning device 2 for welding the cutter box, and the circle center of an inscribed circle of the square positioning frame coincides with the circle center of the inscribed circle of the rack 21; the centering mechanism 22 is fixed on a square positioning frame of the rack 21 through bolts; the suspension arm support 23 is installed at the top end of the frame 21, four support legs which are ninety degrees with each other are arranged in the middle of the suspension arm support 23, a fixed platform is arranged below the suspension arm support 23, the electromagnetic brake I232 is fixed on the platform, a cylindrical stepped shaft is arranged above the electromagnetic brake I, a counter bore is formed in the cylindrical stepped shaft, a bearing is installed in the counter bore, and the suspension arm rotating body 24 is installed on the suspension arm support 23 through the counter bore inner bearing; an external extending shaft is arranged below the boom rotator 24, a key slot 242 is formed on the external extending shaft, one side of the external extending shaft is provided with a weight box 241, the other side of the external extending shaft is provided with a cantilever mounting fixed support 243, and the boom rod piece 25 is connected with the boom rotator 24 through the cantilever mounting fixed support 243; the pull ring 26 is arranged at the top end of the boom rotator 24 and the upper side of the boom, the two are connected through a pull rope 27, and the weight box 241 and the pull ring 26 jointly maintain the balance of the boom rod 25; a dimension distance mark is arranged on the vertical plane of the suspension arm rod piece 25 and is connected with the cantilever installation fixed support 243 through a bolt; the suspension arm connecting plate 28 is arranged at the joint of the two suspension arms and is connected with the suspension arms through bolts; a movable positioning device 29 is secured on the boom bar 25.

The centering mechanism 22 comprises a screw rod 222 and a support 221, wherein the tail end of the screw rod 222 is a conical tip and is coaxial with the boom rotator 24.

The movable positioning device 29 comprises a fixing plate 291, a fixing bolt 292, a second electromagnetic brake 293, a rotatable scale 294, a vertical telescopic sleeve 295 and a horizontal telescopic sleeve 296, and the movable positioning device 29 is fastened on the boom rod 25 through the fixing plate 291 and the fixing bolt 292; the upper part and the lower part of the symmetrical center line are respectively provided with a sharp tooth to determine the size position of the movable positioning device 29 relative to the positioning reference of the center of the cutter head, and the movable positioning device 29 is fixed by fastening a fixing bolt 292 after the expected position is reached; the second electromagnetic brake 293 is arranged on the fixing plate 291 on one side, and a semi-circular angle scale is engraved on the upper surface of the second electromagnetic brake; a rotating shaft is arranged in an inner hole of the second electromagnetic brake 293, a rotatable scale 294 is arranged at one end of the rotating shaft, a straight notch is formed in the upper part of the rotatable scale 294, angle scales on the upper surface of the second electromagnetic brake 293 can be observed through the notch, and the distances from the two outer surfaces of the rotatable scale 294 to the two inner surfaces of the fixing plate 291 are equal.

The vertical telescopic sleeve ruler 295 and the horizontal telescopic sleeve ruler 296 are composed of a strip-shaped inner graduated scale and a U-shaped outer graduated scale, and a fastening groove is formed in the center of each of the strip-shaped inner graduated scale and the U-shaped outer graduated scale, so that the strip-shaped inner graduated scale and the U-shaped outer graduated scale can be fastened by bolts; the end of the vertical telescopic sleeve ruler 295 is provided with a U-shaped groove, the groove width is equal to the thickness of the horizontal strip-shaped inner graduated scale, and the two horizontal telescopic inner graduated scales are symmetrical about the center line of the inner groove of the vertical telescopic sleeve ruler 295 during assembly.

The utility model provides an auxiliary positioning device for welding a shield machine tool box, and aims to provide a high-precision, low-cost and easy-to-operate welding auxiliary device for welding the shield machine tool box. The cutter head centering device of the shield machine mainly solves the problem of center positioning of a cutter head of the shield machine, and the working principle is as follows: when the opposite sides of the two L-shaped auxiliary circular tubes penetrating through the support base are parallel in pairs and tangent to the excircle of the large circular ring, the two L-shaped auxiliary circular tubes enclose a square with the side length being the diameter of the cutter head of the shield tunneling machine, and the intersection point of two diagonal lines of the square is the center of the cutter head of the shield tunneling machine; in the device, the pull rope fixed on the base is used for replacing the diagonal line of the square, so the intersection point of the two pull ropes is the center point of the cutter head; keeping the side length of the positive direction surrounded by the L-shaped auxiliary circular tube and the relation tangent to the periphery of the cutter head unchanged, moving the position of the supporting base for multiple times, and calculating the average value of the obtained mark points for multiple times to obtain the position of the center point of the cutter head; the utility model provides a hobbing cutter box auxiliary welding and positioning device of a shield tunneling machine cutter head, aiming at the problem that an inclination angle is often formed between the hobbing cutter box of the shield tunneling machine cutter head and a front panel of the cutter head in the outer circumference area of the cutter head, which brings difficulty to the welding and positioning of the cutter box: the device firstly uses a screw rod of a centering mechanism to perform centering, wherein a centering reference point is the center of a cutter head obtained by measurement of a cutter head centering device of the shield machine in the first step, a suspension arm is rotated after the fixation is finished, when a corner reaches a cutter box welding positioning angle, an electromagnetic brake under a cantilever support is started, the rotating suspension arm is locked, a balancing weight can be properly increased or decreased in a weight box for ensuring the level of the cantilever, and a level measuring ruler is used for detecting the levelness of the cantilever; the method comprises the steps of determining the position of a movable positioning device according to scales marked on a cantilever rod piece and the welding positioning size of a tool box, screwing a fixing bolt, locking the position of the movable positioning device, rotating a rotatable scale according to the positioning deflection angle of the tool box, comparing with the angle scale on the upper surface of an electromagnetic brake, starting the electromagnetic brake after reaching a specified angle, locking the rotatable scale, symmetrically extending and retracting the transverse telescopic sleeve ruler according to the two sides of the contour size of the tool box, and then screwing a screw to lock the transverse telescopic sleeve ruler, so that all auxiliary work of the welding positioning of the shield machine tool box is completed.

The above-described embodiments of the utility model are intended to be illustrative only and are not intended to be limiting, as all changes that come within the scope of or equivalence to the utility model are intended to be embraced therein.

Claims

1. The utility model provides a shield constructs quick-witted knife case welding auxiliary positioning device which characterized in that: the cutter head centering device (1) comprises a double-hole positioning base (11), a single-hole supporting base (12), an L-shaped auxiliary circular tube (13) and an auxiliary positioning rope (14), wherein the single-hole supporting base (12) and the double-hole positioning base (11) are placed around a welding cutter head, the L-shaped auxiliary circular tube (13) sequentially penetrates through holes in the base, the L-shaped auxiliary circular tube (13) is tangent to the outer diameter of the cutter head, the auxiliary positioning rope (14) is repeatedly scribed in a region of the cutter head close to the circle center, and the center of an intensive cross point region is a cutter head circle center positioning reference; the auxiliary positioning device (2) for the cutter box welding comprises a rack (21), a centering mechanism (22), a suspension arm support (23), a suspension arm rotating body (24), a suspension arm rod piece (25), a pull ring (26), a pull rope (27), a suspension arm connecting plate (28) and a movable positioning device (29), wherein the rack (21) is arranged on the plane of a cutter head panel.

2. The auxiliary positioning device for the shield tunneling machine tool box welding of claim 1, characterized in that: two double-hole positioning bases (11) of the cutter head centering device (1) are arranged on a diagonal line, the double-hole positioning bases (11) are provided with two vertically crossed through holes, the top of each double-hole positioning base is provided with an outer extension rod (111), and the middle points of the central lines of the two staggered and crossed holes are collinear with the axis of the outer extension rod (111); the L-shaped auxiliary circular tube (13) sequentially penetrates through the opening in the base and is tangent to the outer diameter of the cutter head; the top end of the external extension rod (111) is provided with a through hole, and the positioning auxiliary rope (14) passes through the through hole; the single-hole supporting base (12) is provided with a single through hole, the height of the through hole is equal to the height of a certain hole in the double-hole positioning base (11), two identical L-shaped auxiliary circular tubes (13) penetrate through the through hole of the single-hole supporting base (12) and are tangent to the outer circumference of the cutter head, and a line can be drawn in the area of the cutter head close to the center of a circle along the positioning auxiliary rope (14).

3. The auxiliary positioning device for the shield tunneling machine tool box welding of claim 1, characterized in that: a square positioning frame is reserved in the center of a rack (21) of the auxiliary positioning device (2) for welding the cutter box, and the circle center of an inscribed circle of the square positioning frame coincides with the circle center of the inscribed circle of the rack (21); the centering mechanism (22) is fixed on a square positioning frame of the rack (21) through bolts; the suspension arm support (23) is installed at the top end of the rack (21), four support legs (231) which are ninety degrees to each other are arranged in the middle of the suspension arm support (23), a fixed platform is arranged below the suspension arm support, the electromagnetic brake I (232) is fixed on the platform, a cylindrical stepped shaft is arranged above the electromagnetic brake I, a counter bore is formed in the cylindrical stepped shaft, a bearing is installed in the counter bore, and the suspension arm rotating body (24) is installed on the suspension arm support (23) through the counter bore inner bearing; an outward extending shaft is arranged below the suspension arm rotating body (24), a key slot (242) is formed in the outward extending shaft, a weight box (241) is arranged on one side of the outward extending shaft, a cantilever mounting fixed support (243) is arranged on the other side of the outward extending shaft, and the suspension arm rod piece (25) is connected with the suspension arm rotating body (24) through the cantilever mounting fixed support (243); the pull ring (26) is arranged at the top end of the suspension arm rotating body (24) and the upper side of the suspension arm, the suspension arm rotating body and the suspension arm rotating body are connected through a pull rope (27), and the weight box (241) and the pull ring (26) jointly maintain the balance of a suspension arm rod piece (25); a size distance mark is arranged on the vertical plane of the suspension arm rod piece (25), and the size distance mark is connected with the cantilever installation fixed support (243) through a bolt; the suspension arm connecting plate (28) is arranged at the joint of the two suspension arms and is connected with the suspension arms through bolts; a movable positioning device (29) is fastened to the boom stem (25).

4. The auxiliary positioning device for the shield tunneling machine tool box welding of claim 3, characterized in that: the aligning mechanism (22) comprises a screw rod (222) and a support (221), wherein the tail end of the screw rod (222) is a conical tip and is coaxial with the suspension arm rotating body (24).

5. The auxiliary positioning device for the shield tunneling machine tool box welding of claim 3, characterized in that: the movable positioning device (29) comprises a fixing plate (291), a fixing bolt (292), a second electromagnetic brake (293), a rotatable scale (294), a vertical telescopic sleeve ruler (295) and a transverse telescopic sleeve ruler (296), and the auxiliary positioning device (2) for welding the tool box is fastened on the suspension arm rod piece (25) through the fixing plate (291) and the fixing bolt (292); the upper part and the lower part of the symmetrical center line of the positioning device are respectively provided with a sharp tooth, and the radial size from the movable positioning device (29) to the center of the cutter head can be determined by reading the scale on the cantilever rod piece at the sharp tooth; the second electromagnetic brake (293) is arranged on the fixing plate (291), and a semicircular annular angle scale is arranged on the upper surface of the second electromagnetic brake; a rotating shaft is arranged in an inner hole of the second electromagnetic brake (293), a rotatable scale (294) is arranged at one end of the rotating shaft, a straight notch is formed in the upper portion of the rotatable scale (294), angle scales on the upper surface of the second electromagnetic brake (293) can be observed through the notch, and the distance between the two outer surfaces of the rotatable scale (294) and the two inner surfaces of the fixing plate (291) is equal.

6. The auxiliary positioning device for the shield tunneling machine tool box welding of claim 5, characterized in that: the vertical telescopic sleeve ruler (295) and the horizontal telescopic sleeve ruler (296) consist of a strip-shaped inner graduated scale and a U-shaped outer graduated scale, and a fastening groove is formed in the center of each of the vertical telescopic sleeve ruler and the horizontal telescopic sleeve ruler and can be fastened by bolts; the tail end of the vertical telescopic sleeve ruler (295) is provided with a U-shaped groove, the groove width is equal to the thickness of the horizontal strip-shaped inner graduated scale, and the two horizontal telescopic sleeve rulers are symmetrical about the center line of the inner groove of the vertical telescopic sleeve ruler (295) during assembly.