CN215825137U - Quick offset pipe wrench - Google Patents

Abstract

The utility model relates to a quick offset pipe wrench, which comprises a first tong arm and a second tong arm, wherein a first connecting rod is arranged at the end part of the first tong arm, a first movable tong head is arranged at the end part of the first connecting rod, a second connecting rod is arranged on the first movable tong head, a first connecting plate is arranged on the second connecting rod, a third tong arm is arranged outside the first tong arm, a fourth tong arm is arranged at the end part of the third tong arm, an offset second movable tong head is arranged on the fourth tong arm, a fifth tong arm is arranged in the second tong arm, a second connecting plate is arranged at the end part of the fifth tong arm, a third connecting plate is arranged at the end part of the second connecting plate, and an adjusting nut drives the second movable tong head and the fourth tong arm to move relatively The pipe tongs can meet the application requirements of different pipe diameters, and the construction efficiency and the construction quality can be improved.

Description

Quick offset pipe wrench

Technical Field

The utility model relates to a quick offset pipe wrench, and belongs to the technical field of manual pliers tools.

Background

The pipe wrench is used for clamping and rotating steel pipes, is widely used for mounting petroleum pipelines and civil pipelines, and increases torque by using the taper of a wrench head to bite tubular objects. The pipe tongs in the prior art generally comprise a tong body, a fixed tong head and a movable tong head, wherein the tong body moves independently or oppositely, the fixed tong head and the movable tong head are arranged on the tong body, the interior of a nut arranged on the tong body is in threaded fit with a tong arm of the movable tong head, the movable tong head moves up and down or back and forth along the tong body in the process of rotating the nut, the distance between the movable tong head and the fixed tong head is changed, but the tong head is adjusted by rotating the nut to adapt to longer pipe clamping construction time, and the influence of the rotating tightness of the nut on the clamping force of a pipe is larger, so that the pipe tongs are complex to use and are not beneficial to frequent operation; when the double-arm pliers body drives the movable pliers head to deflect and adjust through the pliers body handle rod and change the angle and the distance between the fixed pliers head and the movable pliers head, the moment is small, the required movement distance is large, the opening degree between the movable pliers head and the fixed pliers head is small, the pliers handle, the fixed pliers head and the movable pliers head are in the coaxial direction, and operation cannot be performed under the condition of working environment limitation, so that the construction efficiency and the operation quality are reduced.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provides a quick offset pipe wrench which is compact in structure, reduces construction acting force and operation space by offset, opposite synchronous deflection and movement linkage of a first movable wrench head and a second movable wrench head, enables an opening angle to be larger when the pipe wrench is opened and smaller when the pipe wrench is clamped, is reliable in support, meets the application requirements of the pipe wrench on different pipe diameters, and is beneficial to improvement of construction efficiency and quality.

The utility model is realized by the following technical scheme:

a quick offset pipe wrench comprises a first wrench arm and a second wrench arm, wherein a first connecting rod is arranged at the end part of the first wrench arm, a vertical first pin shaft is arranged between the first connecting rod and the first wrench arm, a first movable wrench head is arranged at the end part of the first connecting rod, a vertical second pin shaft is arranged between the first connecting rod and the first movable wrench head, a second connecting rod is arranged on the first movable wrench head, a vertical third pin shaft is arranged between the second connecting rod and the first movable wrench head, a first connecting plate vertically sleeved on the first pin shaft is arranged on the second connecting rod, and a vertical fourth pin shaft is arranged between the first connecting plate and the second connecting rod;

the first connecting rods are of V-shaped structures, the end parts of the first connecting rods are positioned in the first clamp arm and the first movable clamp head, the second connecting rods are of V-shaped structures, the end parts of the second connecting rods are positioned in the first movable clamp head, and the two first connecting plates are positioned on two sides of the second connecting rods;

a third clamp arm is arranged outside the first clamp arm, the third clamp arm and the second connecting rod are positioned on two sides of the first connecting rod, a vertical fifth pin shaft is arranged between the third clamp arm and the first clamp arm, a fourth clamp arm is arranged at the end part of the third clamp arm, a vertical sixth pin shaft is arranged between the fourth clamp arm and the third clamp arm, and a second movable clamp head which is offset and arranged opposite to the first movable clamp head is arranged on the fourth clamp arm;

the end part of the second clamp arm is vertically sleeved outside the sixth pin shaft, a fifth clamp arm is arranged in the second clamp arm, a vertical seventh pin shaft is arranged between the fifth clamp arm and the second clamp arm, a second connecting plate is arranged at the end part of the fifth clamp arm, a vertical eighth pin shaft is arranged between the second connecting plate and the fifth clamp arm, a third connecting plate is arranged at the end part of the second connecting plate, and a ninth pin shaft is arranged between the two ends of the third connecting plate and the second connecting plate as well as between the two ends of the third connecting plate and the fourth clamp arm respectively;

the bottom of the second clamp arm is opposite to the first clamp arm, the top of the second clamp arm is positioned outside the fifth clamp arm and the third clamp arm and is in a V-shaped structure, a third connecting rod and a fourth connecting rod which are vertical to each other are respectively arranged on the fifth pin shaft and the seventh pin shaft, and the end parts of the third connecting rod and the fourth connecting rod are hinged;

first tong arm and second tong arm tail end are equipped with the pincers handle of subtend setting, are equipped with the spring between first tong arm and the second tong arm, fourth tong arm distolateral wall is equipped with the limiting plate that is L shape structure, be equipped with adjusting nut between limiting plate and the fourth tong arm, second activity binding clip is 7 font structures and one end pass the limiting plate and be equipped with adjusting nut screw-thread fit's spiral shell groove, all be equipped with a plurality of teeth of subtend setting on second activity binding clip and the first activity binding clip.

The utility model has the beneficial effects that:

(1) the first tong arm pulls the first connecting rod through the first pin shaft in the process of moving opposite to the second tong arm, two ends of the first connecting rod correspondingly deflect around the first pin shaft and the second pin shaft respectively, the first connecting plate pushes the second connecting rod through the fourth pin shaft, and two ends of the second connecting rod correspondingly deflect around the fourth pin shaft and the third pin shaft respectively, so that the first movable tong head correspondingly deflects and moves under the action of the second pin shaft and the third pin shaft, and the opening angle and the distance between the first movable tong head and the second movable tong head are increased or reduced;

(2) in the process that the second clamp arm moves opposite to the first clamp arm, a sixth pin shaft pulls one end of a third clamp arm and one end of a fourth clamp arm, the two ends of the third clamp arm deflect around a fifth pin shaft and a sixth pin shaft correspondingly, the two ends of the fifth clamp arm deflect around a seventh pin shaft and an eighth pin shaft correspondingly, and the two ends of a second connecting plate deflect around an eighth pin shaft and a ninth pin shaft correspondingly, so that the fourth clamp arm deflects around the sixth pin shaft and the ninth pin shaft correspondingly under the action of the third clamp arm and the third connecting plate, and the opening angle and the distance between the second movable clamp head and the first movable clamp head are synchronously increased or reduced;

(3) before clamping, the adjusting nut between the L-shaped limiting plate and the fourth tong arm is rotated, so that the second movable tong head in a 7-shaped structure vertically moves along the limiting plate through the threaded fit of the screw groove and the adjusting nut under the limiting of the limiting plate, the initial distance between the first movable tong head and the second movable tong head is changed, and the application requirements of various pipe diameter ranges are met;

in conclusion, the first movable tong head and the second movable tong head are offset and linked, so that the clamp is convenient to adapt to a narrow pipe fitting clamping working environment; through the subtend action of first tong arm and second tong arm, drive first activity binding clip and second activity binding clip and deflect and remove under corresponding linkage, the opening angle is bigger when making to open, the opening angle is littleer when pressing from both sides tightly, it reduces the required space of work to support the linkage structure compactness, support reliably, the linkage reduces the construction effort, and the subtend synchronous motion through first activity binding clip and second activity binding clip, improve the centre gripping efficiency and the effort to different pipe fittings, only rely on the activity binding clip and the fixed binding clip drawback that the nut adjusted among the avoided traditional structure, thereby satisfy the application demand, efficiency of construction and quality are improved.

Drawings

Fig. 1 is a front perspective view of the present invention.

FIG. 2 is a front view structural diagram of the present invention.

Fig. 3 is a rear perspective view of the present invention.

Fig. 4 is a rear perspective view of the present invention.

FIG. 5 is a front view of the present invention.

The labels in the figure are: the clamp comprises a first clamp arm 1, a second clamp arm 2, a first connecting rod 3, a first pin shaft 4, a first movable clamp head 5, a second pin shaft 6, a second connecting rod 7, a third pin shaft 8, a first connecting plate 9, a fourth pin shaft 10, a third clamp arm 11, a fifth pin shaft 12, a fourth clamp arm 13, a sixth pin shaft 14, a second movable clamp head 15, a fifth clamp arm 16, a seventh pin shaft 17, a second connecting plate 18, an eighth pin shaft 19, a third connecting plate 20, a ninth pin shaft 21, a third connecting rod 22, a fourth connecting rod 23, a first abdicating groove 24, a first abdicating opening 25, a second abdicating groove 26, a second abdicating opening 27, a clamp handle 28, a spring 29, a limiting plate 30, an adjusting nut 31, a screw groove 32 and a clamp tooth 33.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

A quick offset pipe wrench comprises a first wrench arm 1 and a second wrench arm 2, wherein a first connecting rod 3 is arranged at the end part of the first wrench arm 1, a vertical first pin shaft 4 is arranged between the first connecting rod 3 and the first wrench arm 1, a first movable wrench head 5 is arranged at the end part of the first connecting rod 3, a vertical second pin shaft 6 is arranged between the first connecting rod 3 and the first movable wrench head 5, a second connecting rod 7 is arranged on the first movable wrench head 5, a vertical third pin shaft 8 is arranged between the second connecting rod 7 and the first movable wrench head 5, a first connecting plate 9 vertically sleeved on the first pin shaft 4 is arranged on the second connecting rod 7, and a vertical fourth pin shaft 10 is arranged between the first connecting plate 9 and the second connecting rod 7;

the first connecting rod 3 is of a V-shaped structure, the end part of the first connecting rod is positioned inside the first tong arm 1 and the first movable tong head 5, the second connecting rod 7 is of a V-shaped structure, the end part of the second connecting rod is positioned inside the first movable tong head 5, and two first connecting plates 9 are arranged and positioned on two sides of the second connecting rod 7;

a third clamp arm 11 is arranged outside the first clamp arm 1, the third clamp arm 11 and the second connecting rod 7 are positioned at two sides of the first connecting rod 3, a vertical fifth pin shaft 12 is arranged between the third clamp arm 11 and the first clamp arm 1, a fourth clamp arm 13 is arranged at the end part of the third clamp arm 11, a vertical sixth pin shaft 14 is arranged between the fourth clamp arm 13 and the third clamp arm 11, and a second movable clamp head 15 which is offset and arranged opposite to the first movable clamp head 5 is arranged on the fourth clamp arm 13;

the end part of the second clamp arm 2 is vertically sleeved outside the sixth pin shaft 14, a fifth clamp arm 16 is arranged in the second clamp arm 2, a vertical seventh pin shaft 17 is arranged between the fifth clamp arm 16 and the second clamp arm 2, a second connecting plate 18 is arranged at the end part of the fifth clamp arm 16, a vertical eighth pin shaft 19 is arranged between the second connecting plate 18 and the fifth clamp arm 16, a third connecting plate 20 is arranged at the end part of the second connecting plate 18, and a ninth pin shaft 21 is arranged between two ends of the third connecting plate 20 and the second connecting plate 18 and the fourth clamp arm 13 respectively;

the bottom of the second clamp arm 2 is opposite to the first clamp arm 1, the top of the second clamp arm 2 is positioned outside the fifth clamp arm 16 and the third clamp arm 11 and is in a V-shaped structure, a third connecting rod 22 and a fourth connecting rod 23 which are vertical to each other are respectively arranged on the fifth pin shaft 12 and the seventh pin shaft 17, and the end parts of the third connecting rod 22 and the fourth connecting rod 23 are hinged;

a first abdicating groove 24 positioned outside the first forceps arm 1 and the fourth forceps arm 13 is arranged in the third forceps arm 11, a first abdicating port 25 abdicating with the first connecting plate 9 is arranged on the third forceps arm 11, a second abdicating groove 26 positioned outside the first connecting rod 3 is arranged in the fourth forceps arm 13, the fourth forceps arm 13 is in a V-shaped structure, a second abdicating port 27 corresponding to the first connecting plate 9 is arranged on the fifth forceps arm 16, and the second connecting plate 18, the third connecting plate 20 and the fourth forceps arm 13 are obliquely and dislocated;

first tong arm 1 and the 2 tail ends of second tong arm are equipped with the pincers handle 28 of subtend setting, are equipped with spring 29 between first tong arm 1 and the second tong arm 2, the distolateral wall of fourth tong arm 13 is equipped with the limiting plate 30 that is L shape structure, be equipped with adjusting nut 31 between limiting plate 30 and the fourth tong arm 13, second activity binding clip 15 is 7 font structures and one end and passes limiting plate 30 and be equipped with and adjusting nut 31 screw-thread fit's thread groove 32, all is equipped with a plurality of teeth 33 of subtend setting on second activity binding clip 15 and the first activity binding clip 5.

The working principle of the utility model is as follows:

referring to the attached drawings, in a natural state, the first clamp arm 1 and the second clamp arm 2 are tensioned by elastic restoring force of a spring 29, so that the first movable clamp head 5 and the second movable clamp head 15 are in an initial state with a small distance, the end parts of the first clamp arm 1 and the fourth clamp arm 13 are arranged in a first abdicating groove 24, a first connecting plate 9 is correspondingly abdicating through a first abdicating port 25 and a second abdicating port 27, one side of a first connecting rod 3 is positioned in a second abdicating groove 26, the first connecting rod 3 is in a V-shaped structure, a second connecting rod 7 is in a V-shaped structure, the fourth clamp arm 13 is in a V-shaped structure, the top part of the second clamp arm 2 is in a V-shaped structure, so that the whole structure is compact, and the second movable clamp head 15 and the first movable clamp head 5 are respectively offset;

the moment and the holding hand feeling are increased by holding the forceps arms at the tail ends of the first forceps arm 1 and the second forceps arm 2 by hands, when the distance between the first forceps arm 1 and the second forceps arm 2 is pulled, the first forceps arm 1 pulls the first connecting rod 3 through the first pin shaft 4 in the opposite movement process, two ends of the first connecting rod 3 deflect correspondingly around the first pin shaft 4 of the first forceps arm 1 and the second pin shaft 6 of the first movable forceps head 5 respectively, the first connecting rod 3 pulls the first connecting plate 9 through the first pin shaft 4, the first connecting plate 9 pushes the second connecting rod 7 through the fourth pin shaft 10, two ends of the second connecting rod 7 deflect correspondingly around the fourth pin shaft 10 of the first connecting plate 9 and the third pin shaft 8 of the first movable forceps head 5 respectively, the first movable forceps head 5 deflects correspondingly under the action of the second pin shaft 6 and the third pin shaft 8, and the opening angle and the distance between the first movable forceps head 15 and the second movable forceps head are increased;

meanwhile, in the process of opposite movement of the second clamp arm 2, one end of the third clamp arm 11 and one end of the fourth clamp arm 13 are pulled through the sixth pin 14, so that the two ends of the third clamp arm 11 deflect around the fifth pin 12 of the first clamp arm 1 and the sixth pin 14 of the second clamp arm 2 respectively, the fifth clamp arm 16 in the second clamp arm 2 moves correspondingly under the action of the seventh pin 17, so that the two ends of the fifth clamp arm 16 deflect around the seventh pin 17 of the second clamp arm 2 and the eighth pin 19 of the second connecting plate 18 respectively, the fifth clamp arm 16 drives the second connecting plate 18 to move, the two ends of the second connecting plate 18 deflect around the eighth pin 19 of the fifth clamp arm 16 and the ninth pin 21 of the third connecting plate 20 respectively, so that the fourth clamp arm 13 deflects around the sixth pin 14 and the ninth pin 21 respectively under the action of the third clamp arm 11 and the third connecting plate 20, and the position and the angle of the second movable clamp head 15 are changed, the opening angle and the distance between the first movable binding clip 5 and the second movable binding clip 15 are increased, so that a pipe fitting is conveniently arranged between the first movable binding clip 5 and the second movable binding clip 15;

the fifth pin shaft 12 and the seventh pin shaft 17 drive one ends of a third connecting rod 22 and a fourth connecting rod 23 which move oppositely, and the other ends of the third connecting rod 22 and the fourth connecting rod 23 correspondingly deflect around the hinged position of the end part, so that the maximum expansion angle of the first clamp arm 1 and the second clamp arm 2 is stabilized and limited, and the collision of parts caused by excessive expansion is avoided;

similarly, when the first tong arm 1 and the second tong arm 2 are driven to clamp oppositely through the tong handle 28, the first tong arm 1 drives the first connecting rod 3 and the second connecting rod 7 to deflect reversely under the action of the first connecting plate 9, so that the first movable tong head 5 deflects and moves reversely, the first tong arm 1 drives one end of the third tong arm 11, the second tong arm 2 drives the other end of the third tong arm 11, one end of the fourth tong arm 13 and one end of the fifth tong arm 16, the fifth tong arm 16 drives the second connecting plate 18 and the third connecting plate 20 to deflect reversely, so that the fourth tong arm 13 deflects and moves reversely under the action of the third tong arm 11 and the third connecting plate 20, the distance and the end opening angle between the second movable tong head 15 and the first movable tong head 5 are reduced in the deflection and movement processes, so that the pipe clamping is stable and reliable, and the biting force is increased by the tong teeth 33;

according to different pipe diameters to be clamped, the adjusting nut 31 between the L-shaped limiting plate 30 and the fourth tong arm 13 is rotated in advance before clamping, so that the second movable tong head 15 in a 7-shaped structure vertically moves along the limiting plate 30 under the limiting of the limiting plate 30 through the threaded fit of the thread groove 32 and the adjusting nut 31, the initial distance between the first movable tong head 5 and the second movable tong head 15 is changed, and the application requirements of various pipe diameter ranges are met;

in conclusion, the overall structure is compact, the offset and linkage arrangement of the first movable binding clip 5 and the second movable binding clip 15 is convenient to adapt to the narrow pipe fitting clamping working environment, the first movable binding clip 5 is driven to deflect and move under the linkage action of the corresponding first connecting rod 3, the second connecting rod 7 and the first connecting plate 9 through the opposite action of the first binding clip 1 and the second binding clip 2, the second movable binding clip 15 is driven to deflect and move under the linkage action of the corresponding third binding clip 11, the fourth binding clip 13, the fifth binding clip 16, the second connecting plate 18 and the third connecting plate 20, the opening angle of the first movable binding clip 5 and the second movable binding clip 15 is larger when the binding clip is opened, the opening angle is smaller when the binding clip is closed, the supporting linkage structure is compact, the space required by work is reduced, the support is reliable, the construction acting force is reduced through linkage, and the opposite synchronous movement of the first movable binding clip 5 and the second movable binding clip 15 is realized, the clamping efficiency and the acting force of different pipe fittings are improved, the defects that a movable binding clip and a fixed binding clip which are adjusted only by nuts in a traditional structure are overcome, and therefore the application requirement is met, and the construction efficiency and the construction quality are improved.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A quick offset pipe wrench comprises a first tong arm (1) and a second tong arm (2), it is characterized in that the end part of the first clamp arm (1) is provided with a first connecting rod (3), a vertical first pin shaft (4) is arranged between the first connecting rod (3) and the first tong arm (1), a first movable tong head (5) is arranged at the end part of the first connecting rod (3), a vertical second pin shaft (6) is arranged between the first connecting rod (3) and the first movable tong head (5), a second connecting rod (7) is arranged on the first movable binding clip (5), a vertical third pin shaft (8) is arranged between the second connecting rod (7) and the first movable binding clip (5), a first connecting plate (9) which is vertically sleeved on the first pin shaft (4) is arranged on the second connecting rod (7), a vertical fourth pin shaft (10) is arranged between the first connecting plate (9) and the second connecting rod (7);

a third clamp arm (11) is arranged outside the first clamp arm (1), the third clamp arm (11) and the second connecting rod (7) are positioned at two sides of the first connecting rod (3), a vertical fifth pin shaft (12) is arranged between the third clamp arm (11) and the first clamp arm (1), a fourth clamp arm (13) is arranged at the end part of the third clamp arm (11), a vertical sixth pin shaft (14) is arranged between the fourth clamp arm (13) and the third clamp arm (11), and a second movable clamp head (15) which is offset and arranged opposite to the first movable clamp head (5) is arranged on the fourth clamp arm (13);

the end part of the second clamp arm (2) is vertically sleeved outside the sixth pin shaft (14), a fifth clamp arm (16) is arranged in the second clamp arm (2), a vertical seventh pin shaft (17) is arranged between the fifth clamp arm (16) and the second clamp arm (2), a second connecting plate (18) is arranged at the end part of the fifth clamp arm (16), a vertical eighth pin shaft (19) is arranged between the second connecting plate (18) and the fifth clamp arm (16), a third connecting plate (20) is arranged at the end part of the second connecting plate (18), and a ninth pin shaft (21) is arranged between the two ends of the third connecting plate (20) and the second connecting plate (18) and the fourth clamp arm (13).

2. A quick offset pipe wrench as claimed in claim 1, characterised in that the first linkage (3) is of V-shaped configuration and ends within the first tong arm (1) and the first movable tong head (5).

3. Quick offset pipe wrench according to claim 2, characterized in that the second connecting rod (7) is of a V-shaped configuration and ends inside the first movable wrench head (5), and the first connecting plate (9) has two ends on both sides of the second connecting rod (7).

4. The quick offset pipe wrench as claimed in claim 1, wherein a first abdicating groove (24) is formed in the third tong arm (11) and located outside the first tong arm (1) and the fourth tong arm (13), and a first abdicating opening (25) is formed in the third tong arm (11) and abdicating with the first connecting plate (9).

5. A quick offset pipe wrench according to claim 4, characterised in that the fourth tong arm (13) is provided with a second relief groove (26) at the outer part of the first connecting rod (3), and the fourth tong arm (13) is V-shaped.

6. The quick offset pipe wrench as claimed in claim 1, wherein the second tong arm (2) is disposed at a bottom opposite to the first tong arm (1), and the second tong arm (2) is disposed at a top outside the fifth tong arm (16) and the third tong arm (11) and has a V-shaped configuration.

7. The quick offset pipe wrench as claimed in claim 1, wherein the fifth tong arm (16) is provided with a second relief opening (27) corresponding to the first connecting plate (9), and the second connecting plate (18), the third connecting plate (20) and the fourth tong arm (13) are arranged in an inclined and staggered manner.

8. Quick offset pipe wrench according to claim 1, characterized in that the fifth pin (12) and the seventh pin (17) are provided with a vertical third link (22) and a vertical fourth link (23), respectively, and the ends of the third link (22) and the fourth link (23) are hinged.

9. A quick-offset pipe wrench as claimed in claim 1, characterised in that the first and second wrench arms (1, 2) are provided at their ends with opposing handles (28) and a spring (29) is provided between the first and second wrench arms (1, 2).

10. The quick offset pipe wrench as claimed in any one of claims 1 to 9, wherein a limiting plate (30) having an L-shaped structure is disposed on an end side wall of the fourth wrench arm (13), an adjusting nut (31) is disposed between the limiting plate (30) and the fourth wrench arm (13), the second movable wrench head (15) has a 7-shaped structure, one end of the second movable wrench head passes through the limiting plate (30) and is provided with a thread groove (32) in threaded engagement with the adjusting nut (31), and a plurality of wrench teeth (33) are disposed on the second movable wrench head (15) and the first movable wrench head (5) in an opposite direction.

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