High-stability crane hook

Abstract

The invention relates to the technical field of hoisting equipment, in particular to a high-stability crane hook. Comprising a lifting hook, a first adjusting seat moving along the outer wall of the lifting hook is arranged on the upper side of the lifting hook, the outer wall of the lifting hook is provided with a first sliding groove allowing the first adjusting seat to slide in a limited mode, and the outer wall of the first adjusting seat is slidably sleeved with a sliding sleeve used for being connected with a crane. Through the design of the first adjusting seat, when an angle exists between the length direction of the steel wire rope of the crane and the sliding sleeve when the steel wire rope is tightened, the sliding sleeve is pulled through the steel wire rope, the sliding sleeve can drive the first adjusting seat to move along the first sliding groove, and when the pulling force applied by the steel wire rope to the sliding sleeve is larger than the elastic force of a first tension spring, the first adjusting seat is adjusted. The top surface of the sliding sleeve is kept vertical to the length direction of the steel wire rope, and the lifting hook is vertically stressed, so that the situation that the neck part of the lifting hook is directly rubbed with the inner wall of the lifting ring to cause the abrasion of the lifting hook can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of lifting equipment, and particularly relates to a crane hook with high stability. Background Art

[0002] The hook is a commonly used tool in lifting and handling operations, and is widely used in multiple fields such as construction sites, port terminals, and logistics warehouses. With the progress of lifting machinery technology and the improvement of safety production requirements, the design and manufacturing process of hook lifting appliances are also constantly improving.

[0003] When the sizes of the lifting ring and the hook do not match, or when the hook is not vertically aligned with the center of the lifting ring during installation, friction will occur between the hook neck and the inner wall of the lifting ring, resulting in wear and even deformation of the hook and the lifting ring. When the hook hoists a long steel pipe, the rotation of the long steel pipe affected by swinging will drive the hook to rub against the lifting ring or the lifting rope, which will also cause wear of the lifting ring and the steel wire rope. Moreover, the contact positions between the lifting rope and the long steel pipe cannot be fixed. When the two contact positions between the lifting rope and the long steel pipe are different, the long steel pipe will tilt, and the long steel pipe is prone to falling and damage, and it will also damage public facilities and injure workers. Summary of the Invention

[0004] In order to overcome the shortcomings in the prior art, the present invention provides a crane hook with high stability.

[0005] The technical solution is as follows: A crane hook with high stability includes a hook. A first adjusting seat that moves along the outer wall of the hook is arranged on the upper side of the hook. The outer wall of the hook has a first sliding groove for the first adjusting seat to be limited and slide. A sliding sleeve for connecting with a crane is slidably sleeved on the outer wall of the first adjusting seat. A first cavity storing hydraulic oil is provided inside the first adjusting seat. A first piston rod located in the first cavity is fixedly connected to the bottom of the sliding sleeve. A second cavity is provided inside the first adjusting seat and is located below the first cavity and is connected through an oil delivery channel. A first tooth block is slidably arranged in the second cavity. A first tension spring is arranged between the first tooth block and the second cavity. A first arc-shaped tooth plate that cooperates with the first tooth block is fixedly connected in the first sliding groove.

[0006] As a further preference, the radian of the first sliding groove is equal to the radian of the outer wall of the hook.

[0007] As a further preference, a positioning frame is arranged on the hook. The inner wall of the positioning frame has a second sliding groove for the positioning frame to be slidably limited. A first oil cavity storing hydraulic oil is opened at the top of the positioning frame. A second piston rod is slidably connected in the first oil cavity. A second tension spring is arranged between the second piston rod and the first oil cavity. An anti-deviation block is fixedly connected to the second piston rod.

[0008] As a further preference, the curvature of the second chute is equal to the curvature of the inner wall of the hook.

[0009] As a further preference, a pair of cylindrical holes are opened on the top of the positioning frame, and T-shaped columns fixed to the bottom of the anti-deflection block are slidably installed in the cylindrical holes.

[0010] As a further preference, a second oil chamber connected to the first oil chamber and storing hydraulic oil is symmetrically opened in the positioning frame, a second toothed block is slidably installed in the second oil chamber, a third tension spring is arranged between the second toothed block and the second oil chamber, and a second arc-shaped tooth plate cooperating with the second toothed block is fixed in the second slide groove.

[0011] As a further preference, a second adjustment seat is provided on the lower side of the second arc-shaped tooth plate, the outer wall of the hook has a third sliding groove for the second adjustment seat to slide and limit, a connecting seat is provided on the lower side of the second adjustment seat, the top of the connecting seat is fixedly connected to the first cone through a column, the bottom of the second adjustment seat has a cylindrical groove for the first cone to slide and limit, and a pair of elastic blocks that cooperate with the first cone are slidably connected in the cylindrical groove.

[0012] As a further preference, the curvature of the third sliding groove is equal to the curvature of the outer wall of the hook.

[0013] As a further preference, a second frustum is slidably provided on the outer wall of the column to cooperate with a pair of elastic blocks.

[0014] As a further preference, two groups of pins of different lengths are fixed to the top of the connecting seat, and both groups of pins slide through the second adjustment seat. The outer wall of the hook has two groups of slots for inserting the pins. Rotating rods with wire wheels are provided on both sides of the connecting seat, and limit pins are slidably provided on the top of the rotating rod. A limit hole is opened on the top of the rotating rod to match the limit pin.

[0015] The present invention has the following advantages: 1. Through the design of the first adjusting seat of the present invention, when there is an angle between the length direction of the crane wire rope when it is taut and the sliding sleeve, the sliding sleeve can be pulled by the wire rope, so that the sliding sleeve can drive the first adjusting seat to move along the first sliding groove. When the tension applied by the wire rope to the sliding sleeve is greater than the elastic force of the first tension spring, the first tooth block can be engaged with the first arc-shaped tooth plate, so that the tension applied to the sliding sleeve is perpendicular to the top surface of the sliding sleeve. The top surface of the sliding sleeve remains perpendicular to the length direction of the wire rope. The hook is subjected to vertical force, which can prevent the hook neck from directly rubbing against the inner wall of the lifting ring and causing wear of the hook.

[0016] 2. Through the design of the positioning frame in the present invention, when the hook is inclined relative to the hanging ring, the positioning frame can adaptively slide along the second chute under the action of its own weight, so that the positioning frame and the anti-deviation block are always perpendicular. After the first tooth block meshes with the first arc-shaped tooth plate, hydraulic oil can enter the first oil chamber and the second oil chamber, and then the anti-deviation block limits the hanging ring or the lifting rope, preventing the hanging ring or the lifting rope from being worn due to movement within the hook. At the same time, the second tooth-shaped block meshes with the second arc-shaped tooth plate, thereby limiting the anti-deviation block through the positioning frame, and making the hanging ring or the lifting rope more stable under the action of the anti-deviation block. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is an installation schematic diagram of the first arc-shaped tooth plate of the present invention; Figure 3 is an installation schematic diagram of the first piston rod of the present invention; Figure 4 is an installation schematic diagram of the anti-deviation block of the present invention; Figure 5 is an installation schematic diagram of the second arc-shaped tooth plate of the present invention; Figure 6 is an installation schematic diagram of the second piston rod of the present invention; Figure 7 is an installation schematic diagram of the second adjusting seat of the present invention; Figure 8 is an installation schematic diagram of the first frustum of the present invention; Figure 9 is an installation schematic diagram of the rotating rod of the present invention.

[0018] Wherein: 1 - hook, 201 - first adjusting seat, 2011 - first chute, 202 - sliding sleeve, 203 - first piston rod, 204 - oil delivery channel, 205 - first tooth block, 206 - first arc-shaped tooth plate, 301 - positioning frame, 3011 - second chute, 302 - first oil chamber, 303 - second piston rod, 304 - anti-deviation block, 401 - T-shaped column, 501 - second oil chamber, 502 - second tooth-shaped block, 503 - second arc-shaped tooth plate, 601 - second adjusting seat, 602 - third chute, 603 - connecting seat, 604 - column, 605 - first frustum, 606 - elastic clamping block, 701 - second frustum, 801 - pin, 802 - rotating rod, 803 - limit pin. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present invention will be further described below in conjunction with specific embodiments. It should also be noted that, unless otherwise clearly specified and defined, terms such as "set", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] Embodiment 1 A crane hook with high stability, as Figures 1 - 3 shown, includes a hook 1. A first adjusting seat 201 is provided on the upper side of the hook 1. The outer wall of the hook 1 has a first sliding groove 2011 for the first adjusting seat 201 to slide and be limited. The radian of the first sliding groove 2011 is equal to the radian of the outer wall of the hook 1. A sliding sleeve 202 for connecting with the crane is slidably sleeved on the outer wall of the first adjusting seat 201. A first cavity storing hydraulic oil is provided inside the first adjusting seat 201. A first piston rod 203 is fixedly connected to the bottom of the sliding sleeve 202. The bottom end of the first piston rod 203 is slidably clamped into the first cavity. A second cavity communicated through an oil delivery channel 204 is provided inside the first adjusting seat 201. The oil delivery channel 204 is in an L shape. The second cavity is located below the first cavity. A first tooth block 205 is slidably connected inside the second cavity. A first tension spring is provided between the top of the first tooth block 205 and the top of the inner wall of the second cavity. A first arc-shaped tooth plate 206 cooperating with the first tooth block 205 is fixedly connected inside the first sliding groove 2011.

[0021] Initially, the bottom end of the first piston rod 203 abuts against the bottom of the first cavity of the first adjusting seat 201, and there is a gap between the first tooth block 205 and the first arc-shaped tooth plate 206. First, hang the lifting ring into the hook 1. When the size of the lifting ring is larger than that of the hook 1 or the space around the lifting ring is narrow, the lifting ring cannot be perpendicular to the hook 1, resulting in an angle between the length direction of the crane steel wire rope when it is tightened and the sliding sleeve 202. At this time, start the crane. The steel wire rope of the crane exerts a pulling force on the sliding sleeve 202 that is inclined to the top surface of the sliding sleeve 202. The sliding sleeve 202 is stressed and exerts a pulling force on the first piston rod 203. It should be noted that the elastic force of the first tension spring is relatively large. Before the steel wire rope is fully tightened, the pulling force exerted by the steel wire rope on the sliding sleeve 202 is less than the elastic force of the first tension spring. The first tooth block 205 remains stable in the second cavity and exerts a pressure on the first piston rod 203 through the hydraulic oil. The first piston rod 203 is stressed to keep the sliding sleeve 202 stationary relative to the first adjusting seat 201, while the sliding sleeve 202 drives the first adjusting seat 201 to slide along the first chute 2011 under the action of the steel wire rope until the pulling force direction of the steel wire rope is perpendicular to the top surface of the sliding sleeve 202. At this time, the pulling force exerted by the steel wire rope on the sliding sleeve 202 is greater than the elastic force of the first tension spring, causing the sliding sleeve 202 to drive the first piston rod 203 to move along the first cavity of the first adjusting seat 201. The first piston rod 203 pushes the hydraulic oil in the first cavity into the second cavity through the oil delivery channel 204. The hydraulic oil pushes the first tooth block 205 to slide downward, and then the first tooth block 205 meshes with the first arc-shaped tooth plate 206. The first arc-shaped tooth plate 206 limits the position of the first adjusting seat 201 through the first tooth block 205, and the first adjusting seat 201 stops moving, showing the state as Figure 4 shown, and the top surface of the sliding sleeve 202 is perpendicular to the length direction of the steel wire rope.

[0022] Only by exerting a pulling force on the sliding sleeve 202 through the steel wire rope can the above effects be achieved. By making the top surface of the sliding sleeve 202 consistent with the length direction of the steel wire rope, the hook 1 can be vertically stressed, preventing the hook 1 from being worn due to direct friction between the neck of the hook 1 and the inner wall of the lifting ring.

[0023] As Figures 4 - 6 shown, a positioning frame 301 is provided on the hook 1. The inner wall of the hook 1 has a second chute 3011 for sliding and limiting the positioning frame 301. The radian of the second chute 3011 is equal to the radian of the inner wall of the hook 1. A first oil cavity 302 for storing hydraulic oil is centrally opened at the top of the positioning frame 301. The first cavity of the first adjusting seat 201 is connected to the first oil cavity 302 through a hose. A vertical groove is opened on the left side of the sliding sleeve 202. One end of the hose is located in the vertical groove, and the other end is located in the second chute 3011. A second piston rod 303 is vertically slidably connected in the first oil cavity 302. A second tension spring is provided between the bottom end of the second piston rod 303 and the bottom of the inner wall of the first oil cavity 302. A deviation prevention block 304 is fixedly connected to the top of the second piston rod 303.

[0024] As Figure 6 shown, cylindrical holes are symmetrically formed at the top of the positioning frame 301. The two cylindrical holes are distributed on the left and right sides of the second piston rod 303. A T-shaped column 401 fixedly connected to the bottom of the anti-deviation block 304 is slidably installed in the cylindrical holes.

[0025] As Figure 5 with Figure 6 shown, second oil cavities 501 communicating with the first oil cavity 302 and storing hydraulic oil are symmetrically formed in the positioning frame 301. The two second oil cavities 501 are distributed on the left and right sides of the first oil cavity 302. A second toothed block 502 is vertically slidably installed in the second oil cavity 501. A third tension spring is arranged between the top of the second toothed block 502 and the inner top of the second oil cavity 501. A second arc-shaped toothed plate 503 cooperating with the second toothed block 502 is fixedly connected in the second chute 3011.

[0026] When the lifting hook 1 is inclined to the hanging ring, the positioning frame 301 adaptively slides along the second chute 3011 under the action of its own weight, and drives the anti-deviation block 304 to move through the second piston rod 303, so that the positioning frame 301 and the anti-deviation block 304 are always perpendicular, and the anti-deviation block 304 is always located below the contact point between the lifting hook 1 and the hanging ring. When the first toothed block 205 meshes with the first arc-shaped toothed plate 206, the hydraulic oil can no longer enter the second cavity of the first adjusting seat 201. The first piston rod 203 continues to move, and pushes the hydraulic oil into the first oil cavity 302 through the hose. The hydraulic oil exerts a thrust on the second piston rod 303, so that the second piston rod 303 drives the anti-deviation block 304 to move upward. The anti-deviation block 304 drives the two T-shaped columns 401 to slide upward along a pair of cylindrical holes of the positioning frame 301. After the anti-deviation block 304 moves, it contacts the hanging ring or the suspension rope. Through the V-shaped surface at the top of the anti-deviation block 304, the hanging ring or the suspension rope can be limited, preventing the hanging ring or the suspension rope from being worn due to movement in the lifting hook 1. Subsequently, the T-shaped column 401 abuts against the top of the cylindrical hole, and the second piston rod 303 passes over the communication part between the first oil cavity 302 and the second oil cavity 501. The hydraulic oil enters the two second oil cavities 501 and pushes the second toothed block 502 to slide downward. After the second toothed block 502 moves, it meshes with the second arc-shaped toothed plate 503, so as to limit the anti-deviation block 304 through the positioning frame 301, making the hanging ring or the suspension rope more stable under the action of the anti-deviation block 304.

[0027] After the lifting is completed, the wire rope is released by the crane, and the wire rope no longer applies tension to the sleeve 202. Since the elastic force of the third tension spring is greater than the elastic force of the second tension spring, and the elastic force of the second tension spring is greater than the elastic force of the first tension spring, the third tension spring first contracts to drive the second toothed block 502 to reset. The hydraulic oil in the second oil chamber 501 flows back to the first cavity of the first adjusting seat 201 through the first oil chamber 302 and the hose under the action of the second toothed block 502. Then, the second tension spring contracts and drives the anti-deflection block 304 to reset through the second piston rod 303. The hydraulic oil in the first oil chamber 302 flows back to the first cavity of the first adjusting seat 201 through the first oil chamber 302 and the hose under the action of the second piston rod 303. Then, the first tension spring contracts to drive the first toothed block 205 to reset. The hydraulic oil in the second cavity flows back to the first cavity through the oil transfer channel 204 under the action of the first toothed block 205. The first piston rod 203 drives the sleeve 202 to reset under the action of the hydraulic oil.

[0028] like Figures 7 - 9 As shown, a second adjusting seat 601 is provided on the lower side of the second arc-shaped tooth plate 503, and the outer wall of the hook 1 has a third slide groove 602 for the second adjusting seat 601 to slide and limit. The curvature of the third slide groove 602 is equal to the curvature of the outer wall of the hook 1, and a connecting seat 603 is provided on the lower side of the second adjusting seat 601. The connecting seat 603 is fixedly connected to the column 604, and the top of the column 604 is fixedly connected to the first cone 605. A cylindrical groove is provided in the center of the bottom of the second adjusting seat 601, and the first cone 605 slides into the cylindrical groove. The cylindrical groove is symmetrically slidably connected with an elastic block 606 that cooperates with the first cone 605. The outer wall of the column 604 is vertically slidably provided with a second cone 701 that cooperates with a pair of elastic blocks 606.

[0029] like Figure 8 and Figure 9 As shown, two groups of pins 801 of different lengths are fixed to the top of the connecting seat 603, and the front and rear opposite pins 801 form a pair. Both groups of pins 801 slide through the second adjustment seat 601. Two groups of slots for inserting the pins 801 are provided at the bottom and left side of the outer wall of the hook 1, with four in each group. Rotating rods 802 are hinged on both sides of the connecting seat 603, and one end of the rotating rod 802 is rotatably connected to the wire wheel. A limit pin 803 is slidingly provided on the top of the connecting seat 603, and a limit hole matching the limit pin 803 is provided on the top of the rotating rod 802.

[0030] Initially, the second adjustment seat 601 is located directly below the hook 1. Two groups of pins 801 are inserted into a group of slots at the bottom of the hook 1. The bottom end of the first frustum 605 abuts against the tops of the two elastic blocks 606. When it is necessary to hoist a long steel pipe or other hoisting objects whose hoisting points cannot be fixed through a hoisting rope, the hoisting ropes are respectively placed on the wire wheels of the two rotating rods 802. During the hoisting process, if the hoisting points of the hoisting ropes and the hoisted objects slip, the bending points of the hoisting ropes can be restricted by the two wire wheels, preventing the hoisting points of the hoisting ropes from slipping to the center of the hoisted objects, which may cause the hoisted objects to be easily balanced.

[0031] When it is necessary to hoist through a lifting ring, push the connection seat 603 upward. The connection seat 603 drives the first frustum 605 and the second frustum 701 to slide upward through the column 604. After the second frustum 701 slides, it contacts the inclined surfaces of the two elastic blocks 606 and pushes the two elastic blocks 606 away from each other until the top end of the second frustum 701 crosses the inclined surfaces of the two elastic blocks 606. The elastic blocks 606 slide back to their original positions and apply a thrust to the conical surface of the second frustum 701, causing the second frustum 701 to slide upward along the column 604. After the second frustum 701 slides, it abuts against the bottom end of the first frustum 605. Then quickly pull the connection seat 603 downward. The connection seat 603 drives the first frustum 605 to quickly move downward through the column 604. The first frustum 605 drives the second frustum 701 to quickly move downward. When the second frustum 701 quickly moves downward, it pushes the two elastic blocks 606 to move away from each other. Since the first frustum 605 and the second frustum 701 are in contact at this time, the two elastic blocks 606 cannot contact the bottom end of the first frustum 605, so that the first frustum 605 can continue to move downward. At this time, the second frustum 701 slides downward along the column 604 under the influence of its own weight and generates a gap with the first frustum 605. At the same time, the connection seat 603 drives the two groups of pins 801 to disengage from the slots on the lower side of the hook 1. Then push the second adjustment seat 601 upward along the third chute 602 until the second adjustment seat 601 contacts the end of the third chute 602. Then push the connection seat 603 again. The connection seat 603 drives the first frustum 605 to push the two elastic blocks 606 to move away from each other through the column 604 until the bottom end of the first frustum 605 crosses the two elastic blocks 606. The two elastic blocks 606 slide back to their original positions and abut against the bottom end of the first frustum 605, so that the gap between the connection seat 603 and the second adjustment seat 601 no longer changes. At the same time, the two groups of pins 801 are inserted into the slots on the left side of the hook 1. Then lift the limit pin 803 upward so that the limit pin 803 disengages from the limit hole of the rotating rod 802. Rotate the two rotating rods 802 ninety degrees to the left, and then insert the limit pin 803 into the limit hole of the rotating rod 802, thus completing the storage of the rotating rod 802, which is convenient for the hook 1 to be hoisted through the lifting ring.

[0032] Although the present disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Accordingly, the scope of the present disclosure should not be limited to the above-described embodiments, but should be determined not only by the appended claims but also by the equivalents of the appended claims.

Claims

1. A crane hook with high stability, comprising a hook (1), characterized in that: On the upper side of the hook (1), a first adjusting seat (201) is provided which moves along the outer wall of the hook (1). The outer wall of the hook (1) has a first sliding groove (2011) for limiting the sliding of the first adjusting seat (201). A sliding sleeve (202) for connecting with a crane is slidably sleeved on the outer wall of the first adjusting seat (201). A first cavity storing hydraulic oil is provided inside the first adjusting seat (201). A first piston rod (203) located inside the first cavity is fixedly connected to the bottom of the sliding sleeve (202). A second cavity is provided inside the first adjusting seat (201) and is located below the first cavity and communicated through an oil delivery channel (204). A first tooth block (205) is slidably arranged inside the second cavity. A first tension spring is arranged between the first tooth block (205) and the second cavity. A first arc-shaped tooth plate (206) cooperating with the first tooth block (205) is fixedly connected inside the first sliding groove (2011).

2. A highly stable crane hook according to claim 1, characterized in that: The radian of the first sliding groove (2011) is equal to the radian of the outer wall of the hook (1).

3. The high-stability crane hook according to claim 2, characterized in that: A positioning frame (301) is provided on the hook (1). Its inner wall has a second sliding groove (3011) for limiting the sliding of the positioning frame (301). A first oil cavity (302) storing hydraulic oil is opened at the top of the positioning frame (301). A second piston rod (303) is slidably connected inside the first oil cavity (302). A second tension spring is arranged between the second piston rod (303) and the first oil cavity (302). An anti-deviation block (304) is fixedly connected to the second piston rod (303).

4. The high - stability crane hook according to claim 3, wherein: The radian of the second sliding groove (3011) is equal to the radian of the inner wall of the hook (1).

5. The high-stability crane hook according to claim 3, wherein: A pair of cylindrical holes are opened at the top of the positioning frame (301). A T-shaped column (401) fixedly connected to the bottom of the anti-deviation block (304) is slidably installed inside the cylindrical holes.

6. The high-stability crane hook according to claim 3, characterized in that: Second oil cavities (501) communicating with the first oil cavity (302) and storing hydraulic oil are symmetrically opened inside the positioning frame (301). A second tooth-shaped block (502) is slidably installed inside the second oil cavity (501). A third tension spring is arranged between the second tooth-shaped block (502) and the second oil cavity (501). A second arc-shaped tooth plate (503) cooperating with the second tooth-shaped block (502) is fixedly connected inside the second sliding groove (3011).

7. The high-stability crane hook according to claim 6, characterized in that: A second adjusting seat (601) is provided below the second arc-shaped tooth plate (503). The outer wall of the hook (1) has a third sliding groove (602) for limiting the sliding of the second adjusting seat (601). An adapter seat (603) is provided below the second adjusting seat (601). A first frustum (605) is fixedly connected to the top of the adapter seat (603) through a column (604). The bottom of the second adjusting seat (601) has a cylindrical groove for limiting the sliding of the first frustum (605). A pair of elastic clamping blocks (606) cooperating with the first frustum (605) are slidably connected inside the cylindrical groove.

8. The high-stability crane hook according to claim 7, characterized in that: The radian of the third sliding groove (602) is equal to the radian of the outer wall of the hook (1).

9. A highly stable crane hook according to claim 7, characterized in that: A second frustum (701) that cooperates with the pair of elastic clamping blocks (606) is slidably arranged on the outer wall of the upright column (604).

10. A highly stable crane hook according to claim 7, characterized in that: Two groups of pins (801) with different lengths are fixedly connected to the top of the connecting seat (603). Both groups of pins (801) slidably penetrate through the second adjusting seat (601). Two slots for inserting the pins (801) are provided on the outer wall of the hook (1). Rotating rods (802) with wire wheels are arranged on both sides of the connecting seat (603). A limiting pin (803) is slidably arranged through the top thereof. A limiting hole that cooperates with the limiting pin (803) is formed at the top of the rotating rod (802).

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