阅读说明：本技术 一种物料提升机防护门联动装置 (Protective door linkage device of material hoister ) 是由 邱凤夏 任涛 盛文斌 俞黎明 邱梁 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种物料提升机防护门联动装置,涉及建筑施工楼层临边防护装置技术领域。技术方案为一种物料提升机防护门联动装置,包括若干楼层下料平台,楼层下料平台一侧搭设有安装架,安装架上安装有物料提升机,楼层下料平台的边缘处设置有围栏,围栏处设置有缺口,且围栏上安装有用于启闭缺口的防护门,围栏上设置有安置孔,防护门部分设置在安置孔内,且防护门的下侧安装有滚轮,安置孔的下侧内壁靠近缺口的一端向下倾斜,缺口处对应设置有凹槽,且凹槽的底面与安置孔的下侧内壁相接并保持平滑,防护门与物料提升机上还对应设置有于防护门打开时对其进行定位的定位机构。本发明结构合理,设置的防护门能够在物料提升机移走时自动关闭。(The invention discloses a protective door linkage device of a material elevator, and relates to the technical field of building construction floor edge protective devices. Technical scheme is a material lifting machine guard gate aggregate unit, including a plurality of floors unloading platform, floor unloading platform one side has been set up the mounting bracket, install material lifting machine on the mounting bracket, the edge of floor unloading platform is provided with the rail, rail department is provided with the breach, and install the guard gate that is used for opening and close the breach on the rail, be provided with the resettlement hole on the rail, the guard gate divides to set up in the resettlement hole, and the downside of guard gate installs the gyro wheel, the downside inner wall of resettlement hole is close to the one end downward sloping of breach, breach department correspondence is provided with the recess, and the bottom surface of recess meets and keeps the level and smooth with the downside inner wall of resettlement hole, still correspond on guard gate and the material lifting machine to be provided with the positioning mechanism. The invention has reasonable structure, and the arranged protective door can be automatically closed when the material lifter moves away.)

1. The utility model provides a material lifting machine guard gate aggregate unit, includes a plurality of floors unloading platform (1), floor unloading platform (1) one side is provided with mounting bracket (2), install material lifting machine (3), its characterized in that on mounting bracket (2): the edge of floor unloading platform (1) is provided with rail (4), rail (4) department is provided with and is used for aiming at breach (5) of material lifting machine (3) in order to supply the unloading, just install on rail (4) and be used for opening and close guard gate (6) of breach (5), be provided with the confession on rail (4) guard gate (6) set hole (7) of retraction when opening, guard gate (6) part sets up in set hole (7), just gyro wheel (8) are installed to the downside of guard gate (6), the downside inner wall of set hole (7) is close to the one end downward sloping of breach (5), breach (5) department corresponds and is provided with recess (9), just the bottom surface of recess (9) with the downside inner wall of set hole (7) meets and keeps level and smooth, guard gate (6) with still correspond on material lifting machine (3) and be provided with when guard gate (6) are opened to guard gate (6) when opening A positioning mechanism (10) for positioning.

2. The protective door linkage device of the material hoister as claimed in claim 1, wherein: the positioning mechanism (10) comprises a positioning part (11) hinged on the protective door (6), the positioning part (11) is connected with a reset torsion spring (12) and horizontally swings, a butt part (13) for abutting against the positioning part (11) is correspondingly arranged on the material lifting machine (3), a slot (14) is arranged on the fence (4), the positioning part (11) extends out from the slot (14), a limit block (15) for limiting the positioning part (11) to swing back to one side of the notch (5) is fixedly connected on the protective door (6), the limit block (15) abuts against one side of the positioning part (11) back to the notch (5), an installation interval (16) is arranged between the material lifting machine (3) and the fence (4), the positioning part (11) and the butt part (13) are arranged in the installation interval (16), the positioning piece (11) is connected with one side, back to the notch (5), of the abutting piece (13) when the protective door (6) is opened and the material lifting machine (3) stops.

3. The protective door linkage device of the material hoister as claimed in claim 1, wherein: the protective door (6) and the material lifting machine (3) are further provided with a limiting mechanism (17) which limits the opening of the protective door (6) when the material lifting machine (3) is not stopped.

4. The material hoist guard door linkage of claim 3, characterized in that: limiting mechanism (17) including articulate rail (4) towards lever (18) of mounting bracket (2) one side, the middle part of lever (18) is articulated and the horizontal hunting, the one end that lever (18) deviates from breach (5) is provided with buckles (19), it is provided with trompil (20) to correspond on rail (4), buckle (19) in when guard gate (6) are closed certainly trompil (20) stretch into and buckle its deviate from breach (5) one side, lever (18) deviate from the one end of buckling (19) with still be provided with spring (21) between rail (4), the both ends of spring (21) are fixed connection respectively in lever (18) with on rail (4), correspond on material lifting machine (3) and be provided with and be used for pushing down lever (18) connect clamp plate (22) of spring (21) one end, the pressing plate (22) is vertically arranged, and two ends of the pressing plate (22) are in a wedge shape which facilitates the sliding of the end part of the lever (18).

5. The material hoist guard door linkage of claim 4, characterized in that: one side of the bend (19) departing from the lever (18) is rotatably connected with a rolling strip (23) which is connected with the protective door (6) in a rolling way.

6. The material hoist guard door linkage of claim 3, characterized in that: limiting mechanisms (17) are arranged up and down and are respectively arranged at the upper side position and the lower side position of the fence (4) facing to one surface of the mounting rack (2).

7. The material hoist guard door linkage of claim 2, characterized in that: guard gate (6) towards fixedly connected with slanted bar (24) are still gone back to the one side of mounting bracket (2), slanted bar (24) are close to breach (5) one end downward sloping, slanted bar (24) certainly fluting (14) department stretches out, fixedly connected with kicking block (25) on material lifting machine (3), be provided with on kicking block (25) with the inclined plane that slanted bar (24) match, inclined plane on kicking block (25) in guard gate (6) are opened just material lifting machine (3) when rising laminate in slanted bar (24), slanted bar (24) in stagger when guard gate (6) are closed the upper and lower position of kicking block (25).

8. The protective door linkage device of the material hoister as claimed in claim 1, wherein: one side of the protective door (6) close to the notch (5) and one side of the fence (4) close to the protective door (6) are both provided with protective pads (26).

9. The protective door linkage device of the material hoister as claimed in claim 1, wherein: one side, back to the mounting frame (2), of the protective door (6) is fixedly connected with a handle (27).

Technical Field

The invention relates to the technical field of building construction floor edge protection devices, in particular to a protective door linkage device of a material elevator.

Background

In the process of building construction, a material elevator is generally used for transporting building materials to more than one floor. The material hoister comprises a steel derrick and an intermediate hanging basket, and materials can be hoisted to each floor of a building by the hanging basket. The material lifting machine is provided with the guard gate at every layer platform of unloading, and the guard gate of material lifting machine's effect is when preventing not stopping at the floor when the hanging flower basket, and operating personnel falls from the opening part carelessly and the major accident appears. The opening and closing of the protective door of the existing material hoister are very troublesome. Because the material lifting machine generally does not allow the electric wire to be attached, the opening of the protective door mostly adopts manual opening and closing, when the hanging flower basket rises to the floor of carrying the material, the protective door needs to be opened by workers, and the protective door is closed after the material is unloaded. Because the manual opening and closing is very troublesome, the situation that workers forget to close the protective door and even open the protective door for a long time to make the protective door become a nominal one often occurs in actual operation, and the hidden trouble of accidents is increased.

In order to solve the problems, a novel protective door linkage device of the material hoister is provided.

Disclosure of Invention

The invention aims to provide a protective door linkage device of a material hoister, which enables a protective door to be automatically closed after the material hoister moves away.

The technical purpose of the invention is realized by the following technical scheme: a protective door linkage device of a material hoister comprises a plurality of floor blanking platforms, wherein one side of each floor blanking platform is provided with a mounting frame, the mounting frame is provided with a material lifter, the edge of the floor blanking platform is provided with a fence, the fence is provided with a notch aligned with the material lifter for blanking, and the fence is provided with a protective door for opening and closing the gap, the fence is provided with a placing hole for the protective door to retract when the protective door is opened, the protective door is partially arranged in the placing hole, and the lower side of the protective door is provided with a roller, one end of the inner wall of the lower side of the placing hole, which is close to the gap, is inclined downwards, the gap is correspondingly provided with a groove, and the bottom surface of the groove is connected with the inner wall of the lower side of the placing hole and keeps smooth, and the protective door and the material lifting machine are correspondingly provided with a positioning mechanism for positioning the protective door when the protective door is opened.

Through adopting above-mentioned scheme, when material lifting machine did not stop at corresponding floor unloading platform, because the downside inner wall in placement hole is close to breach one end downward sloping, and correspond the recess that sets up, the tank bottom also keeps the level and smooth with the downside inner wall in placement hole, and the gyro wheel is installed to the downside of guard gate, so under the natural state, the guard gate can move in order to block the breach to breach one side naturally, avoid the workman to forget the condition of closing the door, when material lifting machine stops at floor unloading platform one side after, the workman moves the guard gate in order to open the breach, fix a position the guard gate of opening through the positioning mechanism on guard gate and the material lifting machine this moment, make the guard gate keep the state of opening, thereby reached the guard gate and kept opening when material lifting machine unloading, the automatic effect of keeping closing after the material lifting machine moves away.

The invention is further configured to: positioning mechanism is including articulating the setting element on the guard gate, be connected with reset torsion spring and horizontal swing on the setting element, the last correspondence of material hoist sets up the confession the butt piece of setting element butt, be provided with the fluting on the rail, the setting element certainly fluting department stretches out, just go back fixedly connected with on the guard gate and be used for the restriction the setting element is to deviating from breach one side wobbling stopper, the stopper butt in the setting element dorsad one side of breach, material hoist with be provided with the installation interval between the rail, the setting element with the butt piece sets up in the installation interval, the setting element in the guard gate is opened just butt when material hoist is berthhed in the butt piece dorsad one side of breach.

By adopting the scheme, after the material hoister stops at one side of the corresponding floor blanking platform, the protective door is opened, the positioning piece on the protective door is abutted against the abutting piece and swings to one side of the notch along with the opening of the protective door, then the positioning piece swings back again under the action of the return spring to abut against the limiting block, the protective door is opened, the protective door moves back for a certain distance, and the positioning piece abuts against the abutting piece, because the positioning piece cannot swing away from one side of the notch due to the limiting of the limiting block, the protective door is limited, the protective door cannot move back continuously to close the notch, and therefore when the material hoister stops, when unloading promptly, the guard gate can keep opening the state and avoid influencing the unloading after opening, and after the material lifting machine removed, there was not the spacing of butt piece, and the guard gate can move back in order to close the breach automatically again.

The invention is further configured to: the protective door and the material hoister are also provided with a limiting mechanism for limiting the opening of the protective door when the material hoister is not stopped.

The invention is further configured to: limiting mechanism is including articulating the rail towards the lever of mounting bracket one side, the articulated and horizontal swing in middle part of lever, the lever deviates from the one end of breach is provided with buckles, correspond on the rail and be provided with the trompil, buckle in when the protection door is closed certainly the trompil stretches into and withholds it and deviates from breach one side, the lever deviates from the one end of buckling with still be provided with the spring between the rail, the both ends of spring fixed connection respectively the lever with on the rail, it is used for pushing down to correspond to be provided with on the material lifting machine the lever is connected the clamp plate of spring one end, the vertical setting of clamp plate, just the both ends of clamp plate are convenient the wedge that the lever tip slideed into.

Through adopting above-mentioned scheme, when material lifting machine does not stop in floor unloading platform one side, after the guard gate is closed naturally, because the effect of spring, the lever is provided with the one end of buckling and can keeps stretching into from the trompil, then buckle and be located guard gate breach one side dorsad, when the guard gate is expected to open, buckle and can buckle guard gate breach one side dorsad, thereby restrict its and open, when material lifting machine removes to floor unloading platform one side and stops, the wedge tip of clamp plate leads the one end that the lever is connected with the spring, make the lever slide to the clamp plate on, thereby by the clamp plate depression, then the lever is equipped with the one end perk of buckling, thereby buckle and break away from on the guard gate, make the guard gate can normally open, so can prevent the potential safety hazard that can open the guard gate when material lifting machine does not stop.

The invention is further configured to: one side of the bent lever, which deviates from the lever, is rotatably connected with a rolling strip which is connected with the protective door in a rolling way.

Through adopting above-mentioned scheme, connect the strip rolling in buckling, remove the back at the material lifting machine, the strip rolling butt is on the guard gate, and when guard gate self-closing breach, the strip rolling on the guard gate to avoid buckling and the too big and unable normal closing of protective gate that leads to of frictional force between the guard gate.

The invention is further configured to: the limiting mechanisms are arranged on the upper portion and the lower portion and are respectively arranged at the upper side position and the lower side position of the fence facing to one face of the mounting rack.

Through adopting above-mentioned scheme, set up two limiting mechanism respectively in the upper and lower side position of rail, then the guard gate just can be opened when the material lifting machine blocks the breach position, prevents that the material lifting machine from not stopping when stable just opening the guard gate and the potential safety hazard that exists.

The invention is further configured to: the protective door faces fixedly connected with slanted bar is still gone to the one side of mounting bracket, the slanted bar is close to breach one end downward sloping, the slanted bar certainly fluting department stretches out, fixedly connected with kicking block on the material lifting machine, be provided with on the kicking block with the inclined plane that the slanted bar matches, inclined plane on the kicking block in the protective door is opened just when the material lifting machine rises laminate in the slanted bar, the slanted bar in stagger when the protective door is closed the top and bottom position of kicking block.

Through adopting above-mentioned scheme, when the guard gate is closed, the upper and lower position of kicking block is staggered to the slanted bar on the guard gate, so can not lead to the fact the influence to reciprocating of material lifting machine, after the guard gate is opened again in material lifting machine berth floor unloading platform one side, the kicking block and the slanted bar of material lifting machine decline are kept away from, then can not lead to the fact the influence to the normal closing of guard gate, if the material lifting machine continues to rise, then slanted bar and kicking block interact, the inclined plane of kicking block can promote the slanted bar and guard gate to breach one side removal, thereby supplementary guard gate is slowly closed, avoid guard gate to be blocked by impurity and unable normal closing.

The invention is further configured to: one side that the guard gate is close to the breach with the rail is close to guard gate one side all is provided with the protection and fills up.

Through adopting above-mentioned scheme, be close to breach one side and rail and be close to guard gate one side at the guard gate and set up the protection pad, can avoid the guard gate accidental clamp to hinder the workman when closing, when the guard gate still has to leave less interval and just closes completely, kicking block and slanted bar just break away from.

The invention is further configured to: the protective door is back to one side of the mounting frame and is fixedly connected with a handle.

Through adopting above-mentioned scheme, set up the handle on the guard gate, conveniently remove the guard gate through the handle.

In conclusion, the invention has the following beneficial effects: one is that the protective door can be automatically closed after the material lifter moves away; and the second protection door can not be opened when the material hoister is not stopped, so that potential safety hazards are eliminated.

Drawings

FIG. 1 is a schematic view of the overall structure of the embodiment;

FIG. 2 is a top view of the embodiment with the mounting bracket removed;

FIG. 3 is a schematic diagram of the embodiment with the mounting bracket and the material elevator removed.

Reference numerals: 1. a floor blanking platform; 2. a mounting frame; 3. a material elevator; 4. a fence; 5. a notch; 6. a protective door; 7. placing the hole; 8. a roller; 9. a groove; 10. a positioning mechanism; 11. a positioning member; 12. a return torsion spring; 13. an abutting member; 14. grooving; 15. a limiting block; 16. installing intervals; 17. a limiting mechanism; 18. a lever; 19. bending; 20. opening a hole; 21. a spring; 22. pressing a plate; 23. rolling; 24. oblique strips; 25. a top block; 26. a protective pad; 27. a handle.

Detailed Description

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

As shown in fig. 1, a material lifting machine guard gate aggregate unit, including a plurality of floors unloading platform 1, one side of floor unloading platform 1 is provided with mounting bracket 2, installs material lifting machine 3 on mounting bracket 2, if mounting bracket 2 directly leans on the building setting, then floor unloading platform 1 is the floor of building, if still set up the scaffold frame between mounting bracket 2 and the building, then floor unloading platform 1 is the scaffold frame, and floor unloading platform 1 specifically sets up according to actual conditions.

The edge of the floor blanking platform 1 is provided with a fence 4 for protection, workers are prevented from falling accidentally, the fence 4 is provided with a gap 5 for aligning a material lifter 3 to feed in and out, the gap 5 is provided with an openable protective door 6, the fence 4 on one side of the gap 5 is provided with a placement hole 7 for the protective door 6 to retract when being opened, part of the protective door 6 is arranged in the placement hole 7, the lower side of the protective door 6 is provided with a roller 8, so that the protective door 6 can be conveniently moved when being opened and closed, one end of the lower inner wall of the installation hole, which is close to the gap 5, is downwards inclined, the gap 5 is correspondingly provided with a groove 9 for clamping the protective door 6, the bottom surface of the groove 9 is connected with and keeps smooth with the lower inner wall of the placement hole 7, so that the protective door 6 is guided by an inclined surface and under the action of self gravity when being opened, the roller 8 can roll along the lower inner wall of the placement hole 7 and the bottom surface of the, thereby make guard gate 6 can self-closing, effectively solved the workman and forgot the condition of closing guard gate 6.

As shown in fig. 2 and 3, although the protective door 6 is configured to be automatically closed when opened, this may cause inconvenience when the material elevator 3 unloads, so a positioning mechanism 10 for positioning the protective door 6 when opened is further correspondingly provided on the protective door 6 and the material elevator 3.

The positioning mechanism 10 comprises a positioning part 11 hinged on the protection door 6, a reset torsion spring 12 is fixedly connected on the protection door 6, the positioning part 11 is enabled to be kept to point to one side of the mounting frame 2 through the action of the reset torsion spring 12, and, in a normal state, the positioning part 11 horizontally swings, an abutting part 13 for abutting and positioning the positioning part 11 is correspondingly arranged on the material lifting machine 3, a slot 14 is arranged on the fence 4, the positioning part 11 extends out from the slot 14, and still fixedly connected with is used for restricting setting element 11 to keeping away from breach 5 one side wobbling stopper 15 on the guard gate 6, stopper 15 butt in the setting element 11 one side of keeping away from breach 5, is provided with installation interval 16 between material lifting machine 3 and the rail 4, and setting element 11 and butt 13 set up in installation interval 16, and setting element 11 butt in the one side of butt 13 back to breach 5 when guard gate 6 is opened and material lifting machine 3 stops in floor unloading platform 1 one side.

After the material hoister 3 stops at one side of the corresponding floor blanking platform 1, the protective door 6 is opened, along with the opening of the protective door 6, the positioning piece 11 on the protective door 6 abuts against the abutting piece 13 and swings to one side of the gap 5, then the positioning piece 11 swings back again through the action of the reset spring 21 and abuts against the limiting piece 15, the protective door 6 is opened again, the protective door 6 moves back for a certain distance, the positioning piece 11 abuts against the abutting piece 13, due to the limiting of the limiting piece 15, the positioning piece 11 cannot swing to one side away from the gap 5, so that the protective door 6 is limited, the protective door 6 cannot move back to close the gap 5, therefore, when the material hoister 3 stops, namely when unloading, the protective door 6 can be kept in an open state after being opened to avoid influencing the unloading, and when the material hoister 3 moves away, the limiting of the abutting piece 13 is avoided, the guard door 6 can automatically move back to close the gap 5.

The structure of the protective door 6 is further improved, the protective door 6 is prevented from being opened when the material hoister 3 is not stopped, potential safety hazards are eliminated, and a limiting mechanism 17 for limiting the opening of the protective door 6 when the material hoister 3 is not stopped is arranged on the protective door 6 and the material hoister 3.

Limiting mechanism 17 is including articulating the lever 18 that faces mounting bracket 2 one side at rail 4, the middle part of lever 18 articulates on a articulated seat of fixed connection on rail 4, make lever 18 can the horizontal hunting, the one end that lever 18 deviates from breach 5 is provided with the trompil 19, it is provided with trompil 20 to correspond on rail 4, 19 buckle stretch into and buckle its one side that deviates from breach 5 from trompil 20 when guard gate 6 closes, lever 18 deviates from still is provided with spring 21 between the one end of 19 and the rail 4 of buckling, the both ends of spring 21 are fixed connection respectively on lever 18 and rail 4, it is used for depressing the clamp plate 22 of lever 18 connecting spring 21 one end to correspond on the material lifting machine 3, the vertical setting of clamp plate 22, and the both ends of clamp plate 22 are the wedge that makes things convenient for lever 18 tip to slide.

Two restricting mechanisms 17 are provided vertically and are provided at upper and lower positions of one surface of the rail 4 facing the mounting frame 2.

When the material hoister 3 is not stopped at one side of the floor blanking platform 1 and the protective door 6 is naturally closed, due to the action of the spring 21, the end of the lever 18 provided with the bend 19 can remain extended from the opening 20, then the bending part 19 is positioned at one side of the protective door 6, which is back to the gap 5, when the protective door 6 is to be opened, the bending part 19 can buckle one side of the protective door 6, which is back to the gap 5, thereby limiting the opening of the material lifting machine, when the material lifting machine 3 moves to one side of the floor blanking platform 1 to stop, the wedge-shaped end of the pressure plate 22 guides the end of the lever 18, to which the spring 21 is connected, so that the lever 18 slides onto the pressure plate 22, and is thus pressed by the pressure plate 22, the end of the lever 18 provided with the bend 19 is tilted, so that the bend 19 is disengaged from the guard door 6, make guard gate 6 can normally open, so can prevent that material lifting machine 3 from opening the potential safety hazard of guard gate 6 when not berthhing. And set up two limiting mechanism 17 respectively in the upper and lower side position of rail 4, then just can open in order to make material lifting machine 3 block 5 positions in the time guard gate 6, prevent that material lifting machine 3 from not stopping when stable just opening guard gate 6 and the potential safety hazard that exists, as long as one of them limiting mechanism 17 withstands guard gate 6, guard gate 6 just can't be opened, indicate when two limiting mechanism 17 all remove that material lifting machine 3 has moved to the position that covers two limiting mechanism, blocked breach 5 promptly.

When the material lifter 3 moves away, the bend 19 is pressed on the protective door 6 due to the action of the spring 21, in order to avoid that the friction force between the bend 19 and the protective door 6 influences the normal closing of the protective door 6, the side of the bend 19, which is far away from the lever 18, is rotatably connected with the roller 23, and the roller 23 is supported on the protective door 6 to roll, so that the sliding friction between the bend 19 and the protective door 6 is changed into rolling friction, and the obstruction to the closing of the protective door 6 is reduced.

Because there are some sweeps during normal construction and material lifting machine 3 are unloaded, fall into easily and cause the hindrance to the natural closing of guard gate 6 on the lower side inner wall of recess 9 and resettlement hole 7, in order to reduce these influences, set up auxiliary device on guard gate 6 and material lifting machine 3 and closed when the material lifting machine 3 moves away with the supplementary guard gate 6. The concrete structure does, 6 at the guard gate to one side fixed connection slanted bar 24 of mounting bracket 2, the slanted bar 24 is close to the one end slope of breach 5 downwards, slanted bar 24 stretches out from fluting 14 department, fixedly connected with kicking block 25 on the material lifting machine 3, be provided with the inclined plane that matches with slanted bar 24 on the kicking block 25, the inclined plane on the kicking block 25 is opened in guard gate 6 and is laminated in slanted bar 24 when material lifting machine 3 rises, and the slanted bar 24 just staggers the upper and lower side position of kicking block 25 when the guard gate 6 is about to close, when kicking block 25 is along with material lifting machine 3 rises, setting element 11 breaks away from with butt piece 13 earlier, then kicking block 25 butt is on slanted bar 24 again. It is noted here that the thickness of both the pressure plate 22 and the slanted bar 24 prevents the slanted bar 24 from abutting against the pressure plate 22 during the movement of the guard door 6.

When the guard gate 6 is closed, the upper and lower position of the liftout block 25 is staggered to the slanted bar 24 on the guard gate 6, so can not lead to the fact the influence to reciprocating of material lifting machine 3, after the guard gate 6 is opened again in 3 stops floor unloading platforms of material lifting machine 1 one side, the liftout block 25 and the slanted bar 24 that the material lifting machine 3 descends are kept away from, then can not lead to the fact the influence to the normal closing of guard gate 6, if continue to rise after 3 stops of material lifting machine, then slanted bar 24 and kicking block 25 interact, the inclined plane of kicking block 25 can promote slanted bar 24 and guard gate 6 and move to 5 one sides of breach, thereby supplementary guard gate 6 is slowly closed, avoid guard gate 6 to be blocked by impurity and can't normally close. In order to reduce the friction between the top block 25 and the slanted bar 24, a roller may be rotatably connected to the surface where the two abut against each other, or a ball may be provided so that the rolling friction is generated between the two.

In order to prevent the protective door 6 from clamping workers when being closed, so when the top block 25 is arranged, the top block 25 is separated from the inclined strip 24 along with the rising of the material lifter 3, a certain interval is left between the protective door 6 and the fence 4, namely the gap 5 is not completely closed, but the width of the interval is not large, the gap cannot be passed by workers, the protective door 6 is left to be naturally closed, a certain space is also left to facilitate the cleaning of impurities falling into the groove 9 and blocking the closing of the protective door 6, and the bending part 19 of the limiting mechanism 17 can be abutted to one side, back to the gap 5, of the protective door 6 for limiting. Furthermore, a protection pad 26 is arranged on one side of the protection door 6 close to the notch 5 and one side of the fence 4 close to the protection door 6, and the protection pad 26 is a soft pad.

One side of the protective door 6, which is back to the mounting frame 2, is fixedly connected with a handle 27, so that the protective door 6 can be controlled to open and close conveniently and actively.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.