CN211588591U - Side drilling device for steel pipe - Google Patents

Abstract

The utility model discloses a side drilling device of steel pipe belongs to mechanical technical field. The device comprises a base, a first clamping external member, a second clamping external member, a connecting support external member and a workbench, wherein the base, the first clamping external member, the second clamping external member, the connecting support external member and the workbench are sequentially connected, a drill rod is arranged on the workbench and can be used for drilling the side face of the steel pipe, and the device can control the drilling direction by accurately locking the drilling position, so that the side face of the steel pipe can be drilled.

Description

Side drilling device for steel pipe

Technical Field

The utility model belongs to the technical field of machinery, a can carry out side drilling's device to the steel pipe is related to.

Background

The steel pipe has relatively high bending resistance and torsion resistance, so the steel pipe is widely applied to the fields of mechanical manufacturing and structural engineering, and in order to facilitate connection, holes are usually punched on the side surface of the steel pipe, so the punching precision and quality of the steel pipe are related to the installation quality of engineering; the general steel pipe side perforating device adopts two kinds of modes of punching a hole or drilling to design, and the production efficiency of punching a hole is higher relatively, and the quality and the precision of drilling are better relatively, but some devices can not pinpoint the steel pipe, lead to the position of punching to appear certain degree skew, and this will seriously weaken the joint strength of steel pipe, and then reduce the extreme use strength of steel pipe, lead to the steel pipe to break off at the position of punching under higher working strength, produce disastrous accident.

Disclosure of Invention

To one or more of the problem that exists among the prior art, the utility model provides a side drilling device of steel pipe, include:

the base comprises a bottom plate (1a) and a first side plate (1b) and a second side plate (1c) which are respectively arranged at two ends of the bottom plate (1 a);

the first clamping external member comprises two first clamping blocks (2) which are movably arranged on the bottom plate (1 a);

the second clamping external member comprises two second clamping blocks (4) which are movably arranged on the first clamping block (2);

the connecting bracket kit comprises two connecting brackets (3), wherein the two connecting brackets (3) and the two second clamping blocks (4) are alternately arranged, and the connecting brackets (3) are movably connected with the second clamping blocks (4);

and the two ends of the workbench (8) are connected with the two connecting supports (3), and a drill rod (9) is arranged on the workbench (8).

The upper surface of the bottom plate (1a) is provided with two first grooves (101) which are parallel to each other, and wheels (a10) matched with the first grooves (101) are arranged on the first clamping block (2); preferably, the first clamping block (2) is provided with a first through groove (202) matched with the first wheel (a10), first through holes (203) are arranged on two sides of the first through groove (202), and the first wheel (a10) is arranged in the first through groove (202) through a first hinge (a 7); further preferably, the first wheels (a10) are four.

The first side plate (1b) is further provided with two first screw holes (102), a first screw rod (a5) matched with the first screw holes (102) is arranged in the first screw holes (102), and the first screw rod (a5) can be in contact with the first clamping block (2).

Two second grooves (201) which are parallel to each other are formed in the upper surface of the first clamping block (2), and second wheels (b10) which are matched with the second grooves (201) are arranged on the second clamping block (4); preferably, the second clamping block (4) is provided with a third groove (403) matched with the second wheel (b10), and both sides of the third groove (403) are provided with fourth through holes (404); the second wheel (b10) is disposed within the third groove (403) by a second hinge (b 7); further preferably, the number of the second wheels (b10) is four.

The two connecting supports (3) are connected with the two second clamping blocks (4) through four connecting rods (6);

the two ends of the second clamping block (4) are respectively provided with a third through groove (401), the upper side and the lower side of the third through groove (401) are respectively provided with a third through hole (402), correspondingly, the two ends of the connecting bracket (3) are respectively provided with a second through groove (302), and the upper side and the lower side of the second through groove (302) are respectively provided with a second through hole (303).

The connecting bracket (3) is of a cuboid structure, a second screw hole (301) is formed in the center of the connecting bracket (3), and a second screw (b5) matched with the second screw hole (301) is arranged in the second screw hole (301); and third screw holes (803) are correspondingly formed at two ends of the workbench (8), wherein the second screw (b5) penetrates through the second screw holes (301) to be connected with the third screw holes (803).

A third wheel (c10) which is matched with the workbench (8) is further arranged on the workbench (8), a fourth through groove (802) which is matched with the third wheel (c10) is further arranged on the workbench (8), seventh through holes (804) are formed in two sides of the fourth through groove (802), and the third wheel (c10) is arranged in the fourth through groove (802) through a third hinge (c 7); preferably, the number of the third wheels (c10) is two.

The workbench (8) is of a cuboid structure, and the drill rod (9) is arranged in a sixth through hole (801) of the workbench (8).

The device also comprises a cushion block (12) arranged between the first clamping block (2) and the second clamping block (4); further preferably, the number of the pad blocks (12) is two.

The upper surface of the padding block (12) is provided with a fourth groove (1201) matched with the second wheel (b10), and the lower surface of the padding block (12) is provided with a boss (1202) matched with the second groove (201).

The utility model provides a drilling rod, screw rod, wheel and hinge are the standard component, screw rod, wheel and hinge under the prerequisite that does not influence its use efficiency, can change the proportional relation of structure or adjust the size of structure.

The side drilling device of steel pipe based on above technical scheme provides can carry out accurate locking to the drilling position of steel pipe, can improve the ultimate service strength of steel pipe, guarantees that the steel pipe can not break under higher working strength to the production of suppression accident. Compared with the prior art, the utility model discloses following beneficial effect has:

1) the device of the utility model uses common materials, has simple structure and is easy to process, therefore, the manufacturing cost of the device is relatively low;

2) the first clamping external member can move directionally on the bottom plate, the second clamping external member can move directionally on the first clamping external member or the cushion block, and the screw can fix the steel pipe, so that the device is relatively good in use safety;

3) the device adopts a symmetrical structural design, the screwing depth of the screw rod in the screw hole of the connecting support is selected according to different outer diameter specifications of the steel pipe, and the steel pipe can be divided into halves vertically by the frame in the shape of eight sides consisting of the second clamping block, the connecting rod and the connecting support, so that the drill rod can be ensured to drill along the radial line direction of the steel pipe, and the drilling precision of the device is relatively high;

to sum up, through the utility model discloses the device can realize carrying out the purpose of side drilling to the steel pipe, has low in manufacturing cost, uses the characteristics that the security is good, drilling accuracy is high.

Drawings

FIG. 1 is a schematic structural view of a side drilling device for a steel pipe in a plan view when drilling a small-caliber steel pipe;

FIG. 2 is a schematic structural view of a side drilling device for a steel pipe in a process of drilling a small-caliber steel pipe;

FIG. 3 is a left side view structural schematic diagram of the steel pipe side drilling device during drilling of a small-caliber steel pipe;

FIG. 4 is a schematic top view of the side drilling device for steel pipes for drilling large-diameter steel pipes;

FIG. 5 is a schematic structural view of a side drilling device for steel pipes in a large-diameter steel pipe drilling process;

FIG. 6 is a left side view structural diagram of the steel pipe side drilling device during drilling of a large-diameter steel pipe;

FIG. 7 is a schematic front view of the assembled first block and the pad block of the steel pipe side drilling device;

FIG. 8 is a left side view structural schematic diagram of the assembled first clamping block and the pad block of the steel pipe side drilling device;

FIG. 9 is a schematic bottom view of the second detent block and the wheels of the steel pipe side drilling apparatus after assembly;

FIG. 10 is a left side view of the second detent block and the wheel of the steel pipe side drilling apparatus after assembly;

FIG. 11 is a schematic top view of the table and wheels of the steel pipe side drilling apparatus after assembly;

FIG. 12 is a left side elevational schematic view of the table, wheels and drill stem of the steel pipe side drilling apparatus after assembly;

FIG. 13 is a front view of the table and wheels of the steel pipe side drilling apparatus after assembly;

FIG. 14 is a front view schematically showing the construction of the connecting bracket of the steel pipe side drilling apparatus;

FIG. 15 is a schematic top view showing the structure of a connecting bracket of the steel pipe side drilling apparatus;

FIG. 16 is a left side view schematically showing the structure of a screw of the steel pipe side drilling apparatus;

FIG. 17 is a schematic top view showing a connecting rod of the steel pipe side drilling apparatus;

FIG. 18 is a schematic view of the working principle of the steel pipe side drilling apparatus;

the reference numerals are represented as:

1 a: a base plate; 1 b: a first side plate; 1 c: a second side plate; 101: a first groove; 102: a first screw hole; 2: a first bit block; 201: a second groove; 202: a first through groove; 203: a first through hole; 3: connecting a bracket; 301: a second screw hole; 302: a second through groove; 303: a second through hole; 4: a second bit block; 401: a third through groove; 402: a third through hole; 403: a third groove; 404: a fourth via hole; a 5: a first screw; b 5: a second screw; 501: a club head; 502: a rod body; 6 connecting rods; 601: a fifth through hole; a 7: a first hinge; b 7: a second hinge; c 7: a third hinge; d 7: a fourth hinge; 8: a work table; 801: a sixth through hole; 802: a fourth through groove; 803: a third screw hole; 804: a seventh via hole; 9: a drill stem; a 10: a first wheel; b 10: a second wheel; c 10: a third wheel; 11: a steel pipe; 12: a cushion block; 1201: a fourth groove; 1202: and (4) a boss.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The embodiments are implemented on the premise of the technical solution of the present invention, and given detailed implementation and specific operation processes, the embodiments will help understanding the present invention, but the scope of the present invention is not limited to the following embodiments.

Example 1:

fig. 1 to 3 show a steel pipe side drilling device provided in this embodiment, which includes a base including a bottom plate 1a and a first side plate 1b and a second side plate 1c respectively disposed at two ends of the bottom plate 1 a; the first clamping external member comprises two first clamping blocks 2 which are movably arranged on the bottom plate 1 a; the second clamping external member comprises two second clamping blocks 4, wherein the second clamping blocks 4 are movably arranged on the first clamping block 2; the connecting bracket assembly comprises two connecting brackets 3, wherein the two connecting brackets 3 and the two second clamping blocks 4 are alternately arranged, and the connecting brackets 3 are movably connected with the second clamping blocks 4; and two ends of the workbench 8 are connected with the two connecting supports 3, and a drill rod 9 is arranged on the workbench 8.

As shown in fig. 1 to 3, the base is made of a metal material and is formed by sequentially and vertically connecting a first side plate 1b, a bottom plate 1a and a second side plate 1c which are equal in length; the upper surface of the bottom plate 1a arranged in the horizontal direction is symmetrically provided with two first grooves 101, the first side plate 1b and the second side plate 1c arranged in the vertical direction are respectively arranged at the left end and the right end of the bottom plate 1a, and the first side plate 1b is symmetrically provided with two first screw holes 102 with axes arranged in the horizontal direction for screwing a first screw rod a 5.

As shown in fig. 1, 7 and 8, the first clamping block 2 is made of a metal material and has a symmetrical structure like a rectangular parallelepiped, two second grooves 201 arranged along the horizontal direction are symmetrically formed on the upper surface of the first clamping block 2, two first through grooves 202 parallel to each other are formed on the lower surface of the first clamping block, and two first through holes 203 are formed on two sides of the first through grooves 202; the first through groove 202 is internally provided with a first wheel a10 which is matched with the first through groove 202, the number of the first wheels a10 is four, and the first wheels a10 are assembled through a first hinge a7 arranged in the first through hole 203, so that the first clamping block 2 can roll in the first groove 101 of the bottom plate 1a through the first wheels a 10; meanwhile, the first screw a5 screwed into the first screw hole 102 of the first side plate 1b pushes the first locking block 2 to move towards the center direction by screwing the first screw a5, so that the distance between the two first locking blocks 2 can be adjusted according to the outer diameter specification of the steel tube 11.

As shown in fig. 9 and 10, the second position-locking block 4 is made of a metal material and has a symmetrical structure like a rectangular parallelepiped, four third grooves 403 arranged in two rows and two columns are formed in the lower surface of the second position-locking block 4, and fourth through holes 404 are formed on two sides of each third groove 403; a second wheel b10 is disposed in the third groove 403, the number of the second wheels b10 is four, and the second wheel b10 is assembled by a second hinge b7 disposed in the fourth through hole 404, so that the second capture block 4 can roll in the second groove 201 of the first capture block 2 via the second wheel b 10; and third through grooves 401 are respectively formed at two ends of the second clamping block 4, and third through holes 402 are formed in the upper side and the lower side of each third through groove 401 and are used for being movably connected with the connecting rod 6.

As shown in fig. 1 and 17, the connecting rod 6 is made of a metal material and has a symmetrical structure like a rectangular parallelepiped, the two ends of the connecting rod 6 are provided with fifth through holes 601, fourth hinges d7 are arranged in the fifth through holes 601, and the second blocking block 4 and the connecting bracket 3 are movably connected in a hinged manner through four connecting rods 6.

As shown in fig. 1, 14, 15, and 16, the connecting bracket 3 is made of a metal material and has a rectangular symmetrical structure, two ends of the connecting bracket 3 are respectively provided with a second through groove 302, upper and lower sides of the second through groove 302 are respectively provided with a second through hole 303, a fourth hinge d7 is arranged in the second through hole 303, a second screw hole 301 is arranged at a center position of the connecting bracket 3, a second screw b5 is arranged in the second screw hole 301, the second screw b5 includes a rod head 501 and a rod body 502, the rod head 501 has a cylindrical symmetrical structure, and the rod body 502 has a cylindrical symmetrical structure with threads on an outer surface thereof and is used for positioning and screwing the workbench 8.

As shown in fig. 11 to 13, the table 8 is made of a metal material and has a rectangular parallelepiped symmetrical structure; the two ends of the workbench 8 are provided with third screw holes 803 for positioning and screwing the second screw rods b 5; the workbench 8 is further symmetrically provided with two fourth through grooves 802, seventh through holes 804 are arranged on two sides of the fourth through grooves 802, adapted third wheels c10 are installed in the fourth through grooves 802, the number of the third wheels c10 is two, and the third wheels c10 are assembled through third hinges c7 arranged in the seventh through holes 804, so that the workbench 8 can roll on the side surface of the steel tube 11 through the third wheels c 10;

example 2:

the steel pipe side drilling device provided by the embodiment is different from the device provided by the embodiment 1 in that the device further comprises the pad block 12, as shown in fig. 4 to 8, the pad block 12 is arranged between the first clamping block 2 and the second clamping block 4, the upper surface of the pad block 12 is provided with a fourth groove 1201 matched with the second wheel b10 for rolling of the second wheel b10, and the lower surface of the pad block 12 is provided with a boss 1202 matched with the second groove 201 for clamping and fixing the pad block 12; thus, when the diameter of the steel pipe 11 to be side-drilled is large, the second locking kit and the working table 8 can be raised correspondingly by arranging the spacer 12, and the distance between the two first locking blocks 2 can be increased correspondingly by simultaneously screwing out the two first screws a5 arranged in the first screw holes 102 of the first side plate 1b, so that the steel pipe 11 can be placed in the device to be drilled.

Taking the steel pipe side drilling device provided in embodiment 1 as an example, as shown in fig. 1 to 17, first, a first wheel a10 is installed at two corresponding positions in each first through slot 202 of each first block 2, so as to ensure that the axle hole of each first wheel a10 is aligned with the first through hole 203 of the corresponding first block 2, and then a first hinge a7 is installed in each aligned through hole, so that the first wheel a10 can be assembled with the first block 2.

Then, a second wheel b10 is mounted in the third groove 403 of each second block 4, so as to ensure that the axle hole of each second wheel b10 is aligned with the corresponding fourth through hole 404 of the second block 4, and then a second hinge b7 is mounted in the through hole of each pair, so that the second wheel b10 can be assembled with the second block 4.

Then, the fifth through holes 601 at one end of the four connecting rods 6 are respectively aligned with the four third through holes 402 of the two second clamping blocks 4, and then a fourth hinge d7 is respectively installed in each aligned through hole, so that the four connecting rods 6 can be assembled with the two second clamping blocks 4.

Then, the fifth through holes 601 at the other ends of the four connecting rods 6 are respectively aligned with the four second through holes 303 of the two connecting brackets 3, and then a corresponding fourth hinge d7 is respectively installed in each aligned through hole, so that the second clamping kit, the four connecting rods 6 and the connecting bracket kit can be assembled.

Then, a third wheel c10 is mounted inside each of the two fourth through slots 802 of the workbench 8, so as to ensure that the axle center hole of each third wheel c10 is aligned with the corresponding seventh through hole 804 of the workbench 8, then a third hinge c7 is mounted inside each aligned through hole, and then a drill rod 9 is mounted inside the sixth through hole 801 of the workbench 8, so that the third wheel c10, the drill rod 9 and the workbench 8 can be assembled.

Then the base is placed on the ground, then two first clamping blocks 2 provided with first wheels a10 are placed on the bottom plate 1a, the first wheels a10 are ensured to be positioned in the first grooves 101 of the bottom plate 1a, then two second clamping blocks 4 provided with second wheels b10 are respectively placed on the two first clamping blocks 2, the second wheels b10 are ensured to be positioned in the second grooves 201 of the first clamping blocks 2, then the third screw holes 803 at both ends of the worktable 8 are respectively aligned with the second screw holes 301 of the two connecting brackets 3, then an adaptive second screw rod b5 is screwed in each screw hole of the alignment, finally an adaptive first screw rod a5 is screwed in each first screw hole 102 of the first side plate 1b, and the whole set of the device is assembled, can be put into use.

The utility model provides a working principle of device does: as shown in fig. 18, each of the point a, the point B, the point C, the point D, the point E, the point F, the point G, and the point H is an axis of a through hole at two ends of the second capture block 4 or the two connecting brackets 3, the point M and the point N are midpoints of the line segment AH and the line segment DE, respectively, and the point X is a midpoint of the line segment MN.

Due to the fact that the device is designed to be of a symmetrical structure, the octagonal frame ABCDEFGH can be guaranteed to be of a symmetrical structure, the hexagon ABCDEFGH and the hexagon HGFENM can be deduced to be identical, the line segment MN is a symmetrical axis of the octagonal frame ABCDEFGH, namely a vertical plane where the line segment MN is located can pass through the axis of the steel pipe 11, and therefore the axis of the drill rod 9 can be guaranteed to be always along the radial direction of the steel pipe 11 in each drilling process.

The use method of the side drilling of the small-caliber steel pipe comprises the following steps: as shown in fig. 1 to 3, the whole of the second locking kit, the four connecting rods 6, the connecting bracket kit and the workbench 8 is lifted from the upper surface of the first locking kit, the steel pipe 11 is stably placed on the bottom plate 1a and between the two first locking blocks 2, and then synchronously screwed into the two first screws a5 in the first screw holes 102 of the first side plate 1b at a constant speed, and when the two first locking blocks 2 can simultaneously contact the steel pipe 11, the screwing of the first screws a5 is stopped.

Then, the whole body formed by the second clamping sleeve member, the four connecting rods 6, the connecting bracket sleeve member and the workbench 8 is stably placed on the first clamping sleeve member again, then the two second screws b5 positioned on the two connecting brackets 3 are synchronously screwed in at a constant speed, when the second wheel b10 installed on the second clamping sleeve member can enter the second groove 201 of the first clamping sleeve member, the two second screws b5 are stopped to be screwed in, then the drill rod 9 positioned in the sixth through hole 801 of the workbench 8 is rotated at a constant speed until a through hole is completely drilled on the side surface of the steel pipe 11, at the moment, the drill rod 9 is stopped to be rotated, and the drilling task is completed.

The use method of the side drilling of the large-diameter steel pipe comprises the following steps: as shown in fig. 4 to 6, the whole body composed of the second locking kit, the four connecting rods 6, the connecting bracket kit and the worktable 8 is lifted from the upper surface of the first locking kit, the steel pipe 11 is stably placed on the bottom plate 1a and between the two first locking blocks 2, and then synchronously screwed into the two first screws a5 in the first screw holes 102 of the first side plate 1b at a constant speed, and when the two first locking blocks 2 can simultaneously contact the steel pipe 11, the screwing of the first screws a5 is stopped.

Then, the two pad blocks 12 are respectively placed on the two first clamping blocks 2, so that the bosses 1202 of the pad blocks 12 can enter the second grooves 201 of the first clamping sleeve members, then the second clamping sleeve members, the four connecting rods 6, the connecting bracket sleeve members and the workbench 8 are stably placed on the pad blocks 12, then the two second screws b5 positioned on the two connecting brackets 3 are synchronously screwed into the whole at a constant speed, when the second wheels b10 arranged on the second clamping sleeve members can enter the fourth grooves 1201 of the pad blocks 12, the screwing of the two second screws b5 is stopped, then the drill rod 9 positioned in the sixth through hole 801 of the workbench 8 is rotated at a constant speed until a through hole is completely drilled on the side surface of the steel pipe 11, and at the moment, the drill rod 9 is stopped to be rotated, and finishing the drilling task operation.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (17)

1. A steel pipe side drilling device, comprising:

the base comprises a bottom plate (1a) and a first side plate (1b) and a second side plate (1c) which are respectively arranged at two ends of the bottom plate (1 a);

the first clamping external member comprises two first clamping blocks (2) which are movably arranged on the bottom plate (1 a);

the second clamping external member comprises two second clamping blocks (4) which are movably arranged on the first clamping block (2);

the connecting bracket kit comprises two connecting brackets (3), wherein the two connecting brackets (3) and the two second clamping blocks (4) are alternately arranged, and the connecting brackets (3) are movably connected with the second clamping blocks (4);

and the two ends of the workbench (8) are connected with the two connecting supports (3), and a drill rod (9) is arranged on the workbench (8).

2. The device according to claim 1, characterized in that the upper surface of the bottom plate (1a) is provided with two first grooves (101) which are parallel to each other, and the first wheel (a10) which is matched with the first grooves (101) is arranged on the first clamping block (2).

3. The device according to claim 2, characterized in that the first block (2) is provided with a first through slot (202) adapted to the first wheel (a10), the first through slot (202) being provided on both sides with a first through hole (203), the first wheel (a10) being provided inside the first through slot (202) by a first hinge (a 7).

4. The device according to claim 2, characterized in that said first wheels (a10) are four.

5. The device according to claim 1, characterized in that said first side plate (1b) is further provided with two first threaded holes (102), said first threaded holes (102) being internally provided with a first screw (a5) adapted thereto, said first screw (a5) being contactable with said first catch block (2).

6. The device according to claim 5, characterized in that the upper surface of the first block (2) is provided with two second grooves (201) parallel to each other, and the second block (4) is provided with a second wheel (b10) matching with the second grooves (201).

7. The device according to claim 6, characterized in that the second block (4) is provided with a third groove (403) adapted to the second wheel (b10), and the third groove (403) is provided with fourth through holes (404) on both sides; the second wheel (b10) is disposed within the third groove (403) via a second hinge (b 7).

8. The device according to claim 6, characterized in that said second wheels (b10) are four.

9. The device according to claim 6, characterized in that the two connecting brackets (3) are connected with the two second detent blocks (4) by four connecting rods (6).

10. The device according to claim 9, wherein both ends of the second clamping block (4) are respectively provided with a third through groove (401), the upper and lower sides of the third through groove (401) are provided with third through holes (402), correspondingly, both ends of the connecting bracket (3) are respectively provided with a second through groove (302), and the upper and lower sides of the second through groove (302) are provided with second through holes (303).

11. The device according to any one of claims 6 to 9, wherein the connecting bracket (3) is a rectangular parallelepiped structure, a second screw hole (301) is formed in the center of the connecting bracket (3), and a second screw (b5) is arranged in the second screw hole (301); and third screw holes (803) are correspondingly formed at two ends of the workbench (8), wherein the second screw (b5) penetrates through the second screw holes (301) to be connected with the third screw holes (803).

12. The device according to claim 11, characterized in that a third wheel (c10) is disposed on the workbench (8), the workbench (8) is further provided with a fourth through slot (802) adapted to the third wheel (c10), a seventh through hole (804) is disposed on two sides of the fourth through slot (802), and the third wheel (c10) is disposed in the fourth through slot (802) through a third hinge (c 7).

13. The device according to claim 12, characterized in that said third wheels (c10) are two.

14. Device according to claim 12, characterized in that the table (8) is of rectangular parallelepiped configuration, the drill rod (9) being arranged inside a sixth through hole (801) of the table (8).

15. The device according to claim 12, further comprising a spacer block (12) arranged between the first capture block (2) and the second capture block (4).

16. The device according to claim 15, characterized in that there are two pad blocks (12).

17. The device according to claim 15, characterized in that the upper surface of the pad block (12) is provided with a fourth groove (1201) adapted to the second wheel (b10), and the lower surface of the pad block (12) is provided with a boss (1202) adapted to the second groove (201).

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