CN110294402B

CN110294402B - Electric hoist

Info

Publication number: CN110294402B
Application number: CN201910595181.XA
Authority: CN
Inventors: 王红华; 齐欢; 吴琪
Original assignee: Zhejiang Xiecheng Crane Machinery Co ltd
Current assignee: ZHEJIANG XIECHENG CRANE MACHINERY Co.,Ltd.
Priority date: 2019-07-03
Filing date: 2019-07-03
Publication date: 2020-11-24
Anticipated expiration: 2039-07-03
Also published as: CN110294402A

Abstract

The invention discloses an electric hoist which comprises a lifting hook shell, a lifting hook space, a hook assembly and a unhooking assembly, wherein the lifting hook space is arranged in the lifting hook shell and is provided with a downward opening, the hook assembly is arranged in the lifting hook space, the unhooking assembly is arranged on a telescopic assembly, the hook assembly comprises a first trapezoidal groove arranged on the rear end wall of the lifting hook space, a first trapezoidal block movably arranged in the first trapezoidal groove, a first rack fixedly arranged at the front end of the first trapezoidal block and a ratchet bar fixedly arranged at the right end of the first rack, and the electric hoist is simple in structure and capable of preventing heavy objects from falling due to overlarge left-right shaking when the heavy objects are lifted.

Description

Electric hoist

Technical Field

The invention belongs to the field of electric hoists, and particularly relates to an electric hoist.

Background

Electric block is a special hoisting equipment, install the overhead traveling crane, on the portal crane, electric block has smallly, the dead weight is light, and is easy for operation, characteristics such as convenient to use, be used for the industrial and mining enterprise, the storage, places such as pier, but traditional electric block makes the lifting hook rotatable on the lifting hook for the convenience of hanging the heavy object, rotatable lifting hook can control slightly rotatoryly when promoting the heavy object or descending, thereby can make the heavy object rock about going on, can make the heavy object drop from the lifting hook when rocking too big pound other equipment or artificial safety accident.

Disclosure of Invention

The invention provides an electric hoist which can avoid heavy objects from falling off due to overlarge shaking during lifting or descending in order to overcome the defects of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme: an electric hoist comprises a hook shell, a hook space, a hook assembly and a unhooking assembly, wherein the hook space is arranged in the hook shell and is provided with a downward opening, the hook assembly is arranged in the hook space, the unhooking assembly is arranged on the telescopic assembly, and the hook assembly comprises a first trapezoidal groove arranged on the rear end wall of the hook space, a first trapezoidal block movably arranged in the first trapezoidal groove, a first rack fixedly arranged at the front end of the first trapezoidal block, a ratchet rack fixedly arranged at the right end of the first rack, two first transmission holes respectively arranged between the front end wall and the rear end wall of the hook space, and a first transmission shaft rotatably arranged between the two first transmission holes.

Has the advantages that: this equipment structure is simple, can avoid the heavy object horizontal rocking too big and drop when mentioning the heavy object, can be convenient for mention the heavy object with first cooperation board and second cooperation board through the couple subassembly, can be convenient for the heavy object through the unhook subassembly and break away from first cooperation board and second cooperation board.

The hook component further comprises a first gear fixedly arranged on the outer surface of the first transmission shaft, two second transmission holes respectively arranged on the right sides of the two first transmission holes, a second transmission shaft rotatably arranged between the two second transmission holes, a second gear fixedly arranged on the outer surface of the second transmission shaft, two third transmission holes arranged on the right sides of the two second transmission holes, a third transmission shaft rotatably arranged in the third transmission holes, and a third gear fixedly arranged on the outer surface of the third transmission shaft.

The hook assembly further comprises a first trapezoidal stroke groove formed in the left end wall of the hook space, a first trapezoidal stroke block which can be vertically and movably arranged in the first trapezoidal stroke groove, a second rack fixedly arranged on the surface of the first trapezoidal stroke block, a fixed rack fixedly arranged on the rear end face of the second rack, and a first matching plate fixedly arranged at the lower end of the second rack.

The hook component further comprises a first telescopic groove arranged at the bottom of the first trapezoidal stroke groove, a first telescopic block arranged in the first telescopic groove, a first spring fixedly arranged at the bottom of the first telescopic block and the first telescopic groove, a second trapezoidal stroke groove arranged at the right end wall of the hook space, a second trapezoidal stroke block arranged in the second trapezoidal stroke groove and capable of moving up and down, a third rack fixedly arranged on the surface of the second trapezoidal stroke block, and a second matching plate fixedly arranged at the lower end of the third rack.

The hook component further comprises a clamping groove which is arranged on the rear end face of the second matching plate and is matched with the first matching plate, a second telescopic groove which is arranged at the bottom of the second trapezoidal stroke groove, a second telescopic block which is arranged in the second telescopic groove, a second spring which is fixedly arranged at the bottom of the second telescopic block and the second telescopic groove, a groove which is arranged on the front end wall of the second trapezoidal stroke groove, a supporting block which is arranged in the groove, and two third springs which are respectively fixedly arranged between the front end wall of the groove and the supporting block.

The couple subassembly is still including setting up two screw holes, two bolts of setting in two screw holes, the fixed rotatory handle that sets up at first transmission shaft front end, the fixed first torsional spring that sets up between first gear and lifting hook space rear end wall, the fixed second torsional spring that sets up between second gear and lifting hook space rear end wall that link up around the fluting front end wall respectively.

The unhooking assembly comprises two shrinkage pieces arranged on the left side and the right side of the rear end face of the lifting hook shell, a first connecting plate fixedly connected between the shrinkage piece on the left side and the trapezoidal stroke block of the second, a second connecting plate fixedly connected between the shrinkage piece on the right side and the trapezoidal stroke block of the first, a push plate fixedly arranged on the shrinkage piece on the left side, and two rotary ratchets fixedly arranged at the rear ends of the first transmission shaft and the second transmission shaft.

The left contraction part comprises a machine shell fixedly arranged on the rear end face of the lifting hook shell, a machine shell space arranged in the machine shell, moving grooves arranged on the left end wall and the right end wall of the machine shell space, a moving block arranged in the machine shell space, and a limiting block which is arranged in the moving grooves in a back-and-forth moving mode and connected with the moving block.

The left side shrink piece is still including the fixed spacing groove that sets up in the movable block rear end face, a plurality of spacing casings of fixed setting on spacing groove end wall, the spacing space of setting in spacing casing, the flexible sloping block of movably setting in spacing space, the fixed fourth spring that sets up between spacing space bottom and flexible sloping block, the cooperation groove of setting at casing space left end wall, the fixed first cooperation sloping block that sets up at the movable block left end face and lie in the cooperation inslot.

The left shrink piece is still including setting up at the left second cooperation sloping block of first cooperation sloping block, fixed straight board that sets up at second cooperation sloping block left end, push pedal fixed connection is at the preceding terminal surface of first cooperation sloping block, the rear end wall in lifting hook space is provided with around link up and with push pedal matched with rectangular channel.

In summary, the invention has the following advantages: the equipment is simple in structure, and the heavy object can be prevented from shaking leftwards and rightwards to be too large and falling off when being lifted.

Drawings

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a first top view of the present invention;

FIG. 3 is a second top view of the present invention;

FIG. 4 is a front view of the present invention;

FIG. 5 is a perspective view, cut away at A-A, of FIG. 2;

FIG. 6 is a partial enlarged view of FIG. 5 at B;

FIG. 7 is an oblique view taken at C-C of FIG. 4;

FIG. 8 is an enlarged view of a portion of FIG. 7 at D;

FIG. 9 is a perspective view, cut away at E-E, of FIG. 3;

FIG. 10 is an enlarged view of a portion of FIG. 9 at F;

FIG. 11 is a cross-sectional view taken at E-E of FIG. 3;

FIG. 12 is an enlarged view of a portion of FIG. 11 at G;

FIG. 13 is an enlarged view of a portion of FIG. 11 at H;

fig. 14 is a sectional perspective view taken at I-I in fig. 2.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

As shown in fig. 1 to 14, in order to achieve the above purpose, the present invention adopts the following technical solutions: an electric hoist 1 comprises a hook housing 2, a hook space which is arranged in the hook housing 2 and has a downward opening, a hook component which is arranged in the hook space, and a unhooking component which is arranged on a telescopic component; the hook component comprises a first trapezoid groove arranged on the rear end wall of the hook space, a first trapezoid block movably arranged in the first trapezoid groove, a first rack 3 fixedly arranged at the front end of the first trapezoid block, a ratchet rack 4 fixedly arranged at the right end of the first rack 3, two first transmission holes respectively arranged between the front end wall and the rear end wall of the hook space, a first transmission shaft 5 rotatably arranged between the two first transmission holes, a first gear 6 fixedly arranged on the outer surface of the first transmission shaft 5, two second transmission holes respectively arranged on the right sides of the two first transmission holes, a second transmission shaft 7 rotatably arranged between the two second transmission holes, a second gear 8 fixedly arranged on the outer surface of the second transmission shaft 7, two third transmission holes arranged on the right sides of the two second transmission holes, a third transmission shaft 9 rotatably arranged in the third transmission holes, a third gear 10 fixedly arranged on the outer surface of the third transmission shaft 9, a first trapezoid block, a second trapezoid block, a ratchet rack 4 fixedly arranged at the front end wall of the hook, A first trapezoidal stroke groove arranged on the left end wall of the lifting hook space, a first trapezoidal stroke block 499 vertically movably arranged in the first trapezoidal stroke groove, a second rack 12 fixedly arranged on the surface of the first trapezoidal stroke block 499, a fixed rack 500 fixedly arranged on the rear end surface of the second rack 12, a first matching plate 301 fixedly arranged at the lower end of the second rack 12, a first telescopic groove arranged at the bottom of the first trapezoidal stroke groove, a first telescopic block 13 arranged in the first telescopic groove, a first spring 14 fixedly arranged at the bottom of the first telescopic block 13 and the first telescopic groove, a second trapezoidal stroke groove arranged on the right end wall of the lifting hook space, a second trapezoidal stroke block vertically movably arranged in the second trapezoidal stroke groove, a third rack 17 fixedly arranged on the surface of the second trapezoidal stroke block, a second matching plate 302 fixedly arranged at the lower end of the third rack 17, A clamping groove which is arranged on the rear end face of the second matching plate 302 and is matched with the first matching plate 301, a second telescopic groove which is arranged at the bottom of the second trapezoidal stroke groove, a second telescopic block which is arranged in the second telescopic groove, a second spring which is fixedly arranged at the bottoms of the second telescopic block and the second telescopic groove, a groove which is arranged on the front end wall of the second trapezoidal stroke groove, a resisting block 21 which is arranged in the groove, two third springs 22 which are respectively and fixedly arranged between the front end wall of the groove and the resisting block 21, two threaded holes which are respectively arranged on the front end wall of the groove and are communicated with each other in the front and back direction, two bolts 23 which are arranged in the two threaded holes, a rotating handle 100 which is fixedly arranged at the front end of the first transmission shaft 5, a first torsion spring 101 which is fixedly arranged between the first gear 6 and the rear end wall of the hook space, and a second torsion spring 102 which is fixedly arranged between the second gear 8 and the rear end; the rotating handle 100 is rotated anticlockwise by a hand, the rotating handle 100 drives the first gear 6 to rotate, the first gear 6 drives the third rack to move downwards, the third rack drives the second matching plate to move downwards, the first gear drives the first rack to move leftwards, when the first rack and the second gear are separated, the second torsion spring which is tightened up clockwise drives the second gear to rotate, the second gear drives the third gear to rotate, the third gear drives the second rack to move downwards, and the second rack drives the first matching plate to move downwards to be inserted into the clamping groove; the first matching plate is inserted into the clamping groove of the second matching plate, so that when a heavy object is hooked, the first matching plate and the second matching plate bear the gravity mutually, and one of the first matching plate and the second matching plate is prevented from being bent due to overlarge stress, and the service life and the stability of equipment are prolonged; the arrangement of the first telescopic block and the second telescopic block can limit the second rack and the third rack when a heavy object is hoisted by the second rack and the third rack, so that the second rack and the third rack are prevented from sliding up and down to shake the heavy object when the heavy object is hoisted or falls, and safety accidents caused by falling off from equipment or colliding people or other equipment in the process of shaking the heavy object are avoided; when the heavy object is lifted upwards or moved downwards, the third rack is pushed forwards to overcome the resistance of the spring to push the abutting block due to the fact that the heavy object is inclined forwards, the bolt can be screwed down to abut against the abutting block before the object in front of the hook is lifted through the arrangement of the bolt, and therefore the situation that the heavy object cannot be supported by the first matching plate and the second matching plate and falls off the equipment due to the fact that the third rack slides forwards and backwards is avoided, safety accidents and damage to the heavy object are avoided, and stability of the equipment is improved; the arrangement of the first trapezoidal stroke block and the second trapezoidal stroke block can limit the second rack and the third rack through the first trapezoidal stroke groove and the second trapezoidal stroke groove, so that a heavy object supporting force can be given by the cooperation of the stroke groove and the stroke block, and the limitation is not required by using the gear and the rack, so that the heavy object is prevented from shaking due to the gap between the gear and the rack when the heavy object is lifted, and the bearing of the gravity of the heavy object through the stroke groove and the stroke block can prevent the gear and the rack from being collided and damaged due to the gap between the gear and the rack when the heavy object is lifted and put down; through all leaving the interval of a ratchet between every ratchet with the ratchet to when can the second gear with ratchet meshing, when every making the second gear anticlockwise rotate a ratchet distance through a ratchet, will utilize the second torsional spring to reset in the interval department of ratchet, thereby can make second gear and ratchet separate the time second cooperation board just can be in the clockwise effect of the second torsional spring that tightens up and move down, thereby can avoid the second cooperation board not reach the first cooperation board just with the lapse of time below the lifting hook casing completely and in the draw-in groove that can't make first cooperation board get into the second cooperation board.

The unhooking assembly comprises two shrinkage pieces, a first connecting plate, a second connecting plate, a push plate 30 and two rotating ratchets 105, wherein the two shrinkage pieces are arranged on the left side and the right side of the rear end face of the lifting hook shell 2; first connecting plate fixed connection is between left shrink piece and trapezoidal stroke piece 16 of second, second connecting plate fixed connection is between right shrink piece and trapezoidal stroke piece 11, push pedal 30 is fixed to be set up on the left shrink piece, two rotatory ratchet 105 are fixed to be set up in first transmission shaft 5 and second transmission shaft 7 rear end.

The left contraction part comprises a machine shell 24 fixedly arranged on the rear end face of the lifting hook shell 2, a machine shell space, a moving groove, a moving block 25, a limiting block, a limiting groove, a plurality of limiting shells 26, a limiting space, a telescopic oblique block 27, a fourth spring, a matching groove, a first matching oblique block 29, a second matching oblique block 31 and a straight plate 32, the machine shell space is arranged in the machine shell 24, the moving groove is arranged on the left end wall and the right end wall of the machine shell space, the moving block 25 is arranged in the machine shell space, the limiting block is arranged in the moving groove in a front-back moving mode and is connected with the moving block 25, the limiting groove is fixedly arranged in the rear end face of the moving block 25, the limiting shells 26 are fixedly arranged on the end walls of the limiting groove, the limiting space is arranged in the limiting shells 26, the telescopic oblique block 27 is movably arranged in the limiting space, the fourth spring is fixedly arranged between the bottom of the limiting space, the matching groove is formed in the left end wall of the space of the machine shell, the first matching inclined block 29 is fixedly arranged on the left end face of the moving block 25 and is located in the matching groove, the second matching inclined block 31 is arranged on the left side of the first matching inclined block 29, the straight plate 32 is fixedly arranged at the left end of the second matching inclined block 31, the push plate 30 is fixedly connected to the front end face of the first matching inclined block 29, the rear end wall of the hook space is provided with a rectangular groove which is penetrated in the front and back direction and is matched with the push plate 30, the first stroke trapezoidal groove is provided with a first sliding groove matched with the first connecting plate 130, the first connecting plate 130 is fixedly connected between the straight plate 32 and the first telescopic block 13, the second connecting plate 104 is fixedly connected between the straight plate and the second telescopic block 19, and the left side contraction part and the right side contraction part are symmetrically arranged; when the lifting hook needs to be unfastened from a heavy object, two moving blocks are pressed by hands, the moving blocks drive the limiting shell to move downwards, so that the first ratchet wheel and the second ratchet wheel are disengaged from the telescopic oblique block 27 on the limiting shell, meanwhile, the moving plates drive the first matching oblique block to move forwards, the push plate is driven to move forwards to push the third rack forwards, so that the first matching oblique block of the first matching plate drives the second matching oblique block to move towards two sides, the first trapezoidal stroke block and the second trapezoidal stroke block enter the first trapezoidal stroke groove and the second trapezoidal stroke groove, meanwhile, the first matching oblique block drives the push plate to move forwards to drive the first rack to move forwards, so that the second matching plate can move forwards to be loosened with the first matching plate, the anticlockwise tightened first torsion spring can be reset, the third rack is reset upwards, the third rack drives the first gear to rotate, the first gear drives the second rack to move rightwards, when the first rack moves to be meshed with the second gear, the second gear drives the third gear to rotate, and the third gear drives the second rack to move upwards, so that the first matching plate and the second matching plate can be separated, and a heavy object can be taken out of the equipment; the arrangement of the plurality of limiting shells can enable the first ratchet wheel and the second ratchet wheel to limit the rotation of the first gear and the second gear when a heavy object is lifted, and also can enable the first gear and the second gear to give a resisting force to the second rack and the third rack, so that the second rack and the third rack are not easy to loosen when the heavy object is lifted, and the equipment can run more stably; make first cooperation board and second cooperation board loosen when setting up through the push pedal can let second rack and third rack rebound to can avoid first cooperation board and second cooperation board to block and make the unable rebound of second rack and third rack reset, thereby improve the stability of equipment.

When the second rack and the third rack are both positioned in the lifting hook space, the first torsion spring is in a loosening state, and the second torsion spring is in a clockwise tightening state.

The torsion of the first torsion spring is larger than that of the second torsion spring.

The first rack is positioned at the rear side of the outer surface of the first gear, and the second gear and the third gear are positioned at the front side of the outer surface of the first gear, so that the three racks can be prevented from interfering with each other in movement.

When the heavy object needs to be removed from the equipment, the bolt needs to be unscrewed forwards until the first matching plate is completely moved out of the clamping groove on the second matching plate.

The rest parts have the same structure as the existing electric hoist.

The working principle is as follows: the rotating handle is rotated anticlockwise by a hand, the rotating handle drives the first gear to rotate, the first gear drives the third rack to move downwards, the third rack drives the second matching plate to move downwards, the first gear drives the first rack to move leftwards, when the first rack and the second gear are separated, the tightened second torsion spring clockwise drives the second gear to rotate, the second gear drives the third gear to rotate, the third gear drives the second rack to move downwards, the second rack drives the first matching plate to move downwards to be inserted into the clamping groove, when the lifting hook needs to be unfastened from a heavy object, the two moving blocks are pressed by the hand, the moving block drives the limiting shell to move downwards, so that the first ratchet wheel and the second ratchet wheel are separated from the telescopic oblique block on the limiting shell, meanwhile, the moving block drives the first matching oblique block to move forwards, the pushing plate is driven to move forwards to push the third rack forwards, and the first matching oblique block of the first matching plate drives the second matching oblique block to move towards two sides, first trapezoidal stroke piece and the trapezoidal stroke piece of second get into first trapezoidal stroke groove and the trapezoidal stroke inslot of second, first cooperation sloping block drives the push pedal and moves forward simultaneously and drives first rack and move forward, thereby can let the second cooperation board move forward and loosen with first cooperation board, thereby can let the first torsion spring that counter-clockwise tightens up reset, thereby let the third rack upwards reset, the third rack drives first gear revolve, first gear drives the second rack and moves right, when first rack move to with second gear engagement, the second gear drives the third gear revolve, the third gear drives the second rack and moves upwards, thereby can let first cooperation board and second cooperation board part and take out the heavy object from equipment.

It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. An electric block, its characterized in that: the hook assembly comprises a first trapezoidal groove arranged on the rear end wall of the hook space, a first trapezoidal block movably arranged in the first trapezoidal groove, a first rack (3) fixedly arranged at the front end of the first trapezoidal block, a ratchet rack (4) fixedly arranged at the right end of the first rack (3), two first transmission holes respectively arranged between the front end wall and the rear end wall of the hook space, and a first transmission shaft (5) rotatably arranged between the two first transmission holes;

the hook assembly further comprises a first gear (6) fixedly arranged on the outer surface of the first transmission shaft (5), two second transmission holes respectively arranged on the right sides of the two first transmission holes, a second transmission shaft (7) rotatably arranged between the two second transmission holes, a second gear (8) fixedly arranged on the outer surface of the second transmission shaft (7), two third transmission holes arranged on the right sides of the two second transmission holes, a third transmission shaft (9) rotatably arranged in the third transmission holes, and a third gear (10) fixedly arranged on the outer surface of the third transmission shaft (9);

the hook assembly further comprises a first trapezoidal stroke groove arranged on the left end wall of the hook space, a first trapezoidal stroke block (499) which can be arranged in the first trapezoidal stroke groove in a vertically moving mode, a second rack (12) fixedly arranged on the surface of the first trapezoidal stroke block (499), a fixed rack (500) fixedly arranged on the rear end face of the second rack (12), and a first matching plate (301) fixedly arranged at the lower end of the second rack (12);

the hook assembly further comprises a first telescopic groove arranged at the bottom of the first trapezoidal stroke groove, a first telescopic block (13) arranged in the first telescopic groove, a first spring (14) fixedly arranged at the bottom of the first telescopic block (13) and the first telescopic groove, a second trapezoidal stroke groove arranged at the right end wall of the hook space, a second trapezoidal stroke block which can be arranged in the second trapezoidal stroke groove in a vertically movable manner, a third rack (17) fixedly arranged on the surface of the second trapezoidal stroke block, and a second matching plate (302) fixedly arranged at the lower end of the third rack (17);

the hook assembly further comprises a clamping groove which is arranged on the rear end face of the second matching plate (302) and matched with the first matching plate (301), a second telescopic groove which is arranged at the bottom of the second trapezoidal stroke groove, a second telescopic block which is arranged in the second telescopic groove, a second spring which is fixedly arranged at the bottoms of the second telescopic block and the second telescopic groove, a groove which is arranged on the front end wall of the second trapezoidal stroke groove, a supporting block (21) which is arranged in the groove, and two third springs (22) which are respectively and fixedly arranged between the front end wall of the groove and the supporting block (21);

the hook assembly further comprises two threaded holes which are respectively arranged on the front end wall of the groove and run through from front to back, two bolts (23) arranged in the two threaded holes, a rotating handle (100) fixedly arranged at the front end of the first transmission shaft (5), a first torsion spring (101) fixedly arranged between the first gear (6) and the rear end wall of the hook space, and a second torsion spring (102) fixedly arranged between the second gear (8) and the rear end wall of the hook space;

the unhooking assembly comprises two shrinkage pieces arranged on the left side and the right side of the rear end face of the lifting hook shell (2), a first connecting plate fixedly connected between the shrinkage piece on the left side and a second trapezoidal stroke block (16), a second connecting plate fixedly connected between the shrinkage piece on the right side and a first trapezoidal stroke block (11), a push plate (30) fixedly arranged on the shrinkage piece on the left side, and two rotating ratchet wheels (105) fixedly arranged at the rear ends of a first transmission shaft (5) and a second transmission shaft (7);

the left contraction part comprises a machine shell (24) fixedly arranged on the rear end face of the lifting hook shell (2), a machine shell space arranged in the machine shell (24), moving grooves arranged on the left end wall and the right end wall of the machine shell space, a moving block (25) arranged in the machine shell space, and a limiting block which is arranged in the moving grooves in a back-and-forth moving mode and connected with the moving block (25);

the left side contraction part also comprises a limiting groove fixedly arranged in the rear end face of the moving block (25), a plurality of limiting shells (26) fixedly arranged on the end walls of the limiting groove, a limiting space arranged in the limiting shells (26), a telescopic inclined block (27) movably arranged in the limiting space, a fourth spring fixedly arranged between the bottom of the limiting space and the telescopic inclined block (27), a matching groove arranged on the left end wall of the space of the casing, and a first matching inclined block (29) fixedly arranged on the left end face of the moving block (25) and positioned in the matching groove;

the left shrink piece is still including setting up at left second cooperation sloping block (31) of first cooperation sloping block (29), fixed straight board (32) that set up in second cooperation sloping block (31) left end, push pedal (30) fixed connection is at the preceding terminal surface of first cooperation sloping block (29), the rear end wall in lifting hook space is provided with one and link up around and with push pedal (30) matched with rectangular channel.