CN115502016A

CN115502016A - PCB circuit board tri-proof lacquer painting equipment

Info

Publication number: CN115502016A
Application number: CN202211139810.6A
Authority: CN
Inventors: 欧阳永明
Original assignee: Shenzhen Hengxin Jietong Electronics Co ltd
Current assignee: Shenzhen Hengxin Jietong Electronics Co ltd
Priority date: 2022-09-19
Filing date: 2022-09-19
Publication date: 2022-12-23
Anticipated expiration: 2042-09-19
Also published as: CN115502016B

Abstract

The invention relates to a painting device, in particular to a three-proofing painting device for a PCB. Need design one kind can be convenient carry out even japanning to PCB board two sides, PCB circuit board three proofings lacquer painting equipment that work efficiency is high. The utility model provides a PCB circuit board three proofings lacquer painting equipment, includes shell, stand and spouts the glassware, and presss from both sides material mechanism, and the shell outer bottom interval rigid coupling has four stands, spouts the glassware and is used for lacquering to the PCB board. According to the invention, the PCB is placed on the material placing plate, the four clamping blocks clamp and limit the PCB, the double-shaft motor and the material sprayer are started to work, then the material sprayer sprays three-proofing paint to paint the PCB, meanwhile, the material placing plate rotates and also drives the PCB to rotate, and the PCB rotates to enable the three-proofing paint to be painted more uniformly, so that two sides of the PCB can be conveniently and uniformly painted, the spraying effect is good, and the working efficiency is high.

Description

PCB circuit board tri-proof lacquer painting equipment

Technical Field

The invention relates to a painting device, in particular to a three-proofing painting device for a PCB.

Background

The PCB, the name of which is printed circuit board, is also called printed circuit board, is an important electronic component, is a support body of electronic components, is a carrier for electrical interconnection of electronic components, and most of the prior PCBs can be sprayed with three-proofing paint.

The chinese patent that publication number is CN213907056U discloses a PCB board three proofings lacquer coating equipment, needs a plurality of motors to carry out the cooperation work to current PCB board three proofings lacquer coating equipment mostly to cause the lower problem of utilization efficiency of motor, now propose following scheme, it includes the base, the top fixed mounting of base has the storage tank body, and the spiral auger is installed in the internal rotation of the storage tank body, and the both ends of spiral auger all extend to the outside of the storage tank body, and the pivot is installed in the inboard top rotation of base, and the top of pivot extends to the outside and the fixed mounting of base has the runner, and the top fixed mounting of runner has the brush board, and the gear is installed in the internal rotation of base. Although above-mentioned patent can realize the spraying of PCB board three proofings lacquer, nevertheless because PCB board both sides all need spray paint, need with the PCB board upset to the another side spraying, relatively troublesome, lead to work efficiency low.

Based on the defects in the patent, the three-proofing paint painting equipment for the PCB, which can conveniently and uniformly paint two sides of the PCB and is high in working efficiency, is provided.

Disclosure of Invention

In order to overcome the defects that the two surfaces of the PCB need to be painted, the PCB needs to be turned over to be painted on the other surface, and the working efficiency is low due to the fact that the PCB is troublesome to spray, the invention provides the three-proofing paint coating equipment for the PCB, which can be used for conveniently and uniformly coating the two surfaces of the PCB and is high in working efficiency.

The technical scheme of the invention is as follows:

the utility model provides a PCB circuit board three proofings lacquer painting equipment, including shell, stand and sprayer, and double-layered material mechanism, the outer bottom interval rigid coupling of shell has four stands, and the sprayer is used for lacquering to the PCB board, still including tilting mechanism and spraying mechanism, is provided with on the shell to be used for providing power and drives PCB board pivoted tilting mechanism, is provided with spraying mechanism between shell and the tilting mechanism, spraying mechanism and sprayer fixed connection, spraying mechanism is used for driving the sprayer removes.

Furthermore, the PCB clamping mechanism is further included, and the turnover mechanism is provided with a clamping mechanism used for clamping and limiting the PCB.

Further, tilting mechanism is including double-shaft motor, dwang and blowing board, and the rigid coupling has double-shaft motor in the middle of the shell outsole portion, all the rotary type is equipped with the dwang in the middle of the shell left and right sides, double-shaft motor left and right sides output shaft respectively with the left and right sides between the dwang through synchronous belt drive, the rigid coupling has the blowing board between the left and right sides dwang.

Further, spraying mechanism is including first frid, first slider, the column rotates, the groovy ring, first guide bar and inlet pipe, upper portion all the rigid coupling has first frid in the left and right sides face in the shell, all slidingtype is equipped with first slider in the first frid of left and right sides, all the rotary type is equipped with the column rotates on the first slider of left and right sides, the left and right sides column rotates all with sprayer fixed connection, left and right sides column bottom portion all the rigid coupling has first guide bar, the first guide bar of left and right sides is located left and right sides inslot respectively, the first guide bar of left and right sides is left and right sides groovy ring sliding connection respectively, the sprayer left and right sides all is connected with the inlet pipe, the equal shell fixed connection of left and right sides, the inlet pipe material is rubber.

Further, the clamping mechanism comprises groove blocks, clamping blocks, screws and threaded tooth blocks, the top of the discharging plate is fixedly connected with the four groove blocks at intervals, the clamping blocks are arranged in the four groove blocks in a sliding mode, the upper portions of the four groove blocks are connected with the screws in a threaded mode, the bottom ends of the four screws are fixedly connected with the four clamping blocks respectively, and the lower portions of the four screws are connected with the threaded tooth blocks in a threaded mode.

Further, still including the locking mechanical system who is used for the synchronous operation clamp splice, locking mechanical system is including the deflector, the apparatus further comprises a rotating shaft, the carousel, column gear and rack, the blowing roof bilateral symmetry rigid coupling has the deflector, left and right sides deflector inboard all rotary type is equipped with the pivot, left and right sides pivot upper portion all rigid coupling has the carousel, left and right sides pivot lower part all rigid coupling has the column gear, four groove block upper portions all slidingtype are equipped with the rack, two racks in the left and left column gear engagement, two racks in the right-hand and right column gear engagement, four racks respectively with the meshing of screw thread tooth piece.

Further, still including being used for drying the stoving mechanism of solidification to three proofings lacquer, drying mechanism is including the second frid, the second slider, stoving ware and second guide bar, all the rigid coupling has the second frid in the lower part in the left and right sides face in the shell, all the slidingtype is equipped with the second slider in the left and right sides second frid, the rigid coupling has the stoving ware that is used for drying the solidification to three proofings lacquer between the left and right sides second slider, left and right sides second slider top all the rigid coupling has the second guide bar, left and right sides second guide bar is located left and right sides inslot respectively, left and right sides second guide bar left and right sides inslot ring sliding connection respectively.

Further, still including the protection machanism who is used for avoiding three proofings to splash, protection machanism is including the third frid, the guard plate, bow-shaped pole and stopper, the outside front and back both sides face of shell all bilateral symmetry rigid coupling has the third frid, slidingtype is equipped with the guard plate that is used for avoiding three proofings to splash between the third frid of the place ahead left and right sides, upper portion all rotary type is equipped with the bow-shaped pole in the guard plate of both sides around, upper portion all rigid coupling has the stopper in the outside front side face of shell, the left and right sides stopper contacts with left and right sides bow-shaped pole respectively.

The invention has the beneficial effects that:

1. according to the invention, the PCB is placed on the material placing plate, the four clamping blocks clamp and limit the PCB, the double-shaft motor and the material sprayer are started to work, then the material sprayer sprays three-proofing paint to paint the PCB, meanwhile, the material placing plate also drives the PCB to rotate, and the PCB rotates to enable the three-proofing paint to be painted more uniformly, so that two sides of the PCB can be painted uniformly conveniently, the spraying effect is good, and the working efficiency is high.

2. Under the effect of stoving mechanism, start the work of drying by fire the ware, the left and right sides second slider reciprocates and drives drying by fire the ware and reciprocate, and drying by fire the ware and reciprocate fast and evenly to the PCB board, so, can conveniently dry by fire the PCB board fast after the lacquer.

3. Under protection machanism's effect, the both sides guard plate can avoid the in-process three proofings lacquer of spraying paint to the operating personnel on one's body around, influences health safety, so, can avoid three proofings lacquer to sputter to the operating personnel on one's body, influence health safety.

Drawings

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

FIG. 2 is a schematic view of a first partial body structure according to the present invention.

Fig. 3 is a schematic perspective view of a second embodiment of the present invention.

Fig. 4 is a schematic perspective view of the turnover mechanism of the present invention.

Fig. 5 is a schematic perspective view of the spray mechanism of the present invention.

Fig. 6 is a schematic perspective view of a part of the spraying mechanism of the present invention.

Fig. 7 is a schematic perspective view of the material clamping mechanism of the present invention.

Fig. 8 is a third perspective view of the present invention.

Fig. 9 is a partial perspective view of the locking mechanism of the present invention.

Fig. 10 is a schematic perspective view of the drying mechanism of the present invention.

Fig. 11 is a schematic perspective view of the protection mechanism of the present invention.

Part names and serial numbers in the figure: 1_ shell, 2_ column, 3_ sprayer, 4_ turnover mechanism, 41_ double-shaft motor, 42_ rotating rod, 43_ discharge plate, 5_ spraying mechanism, 51_ first groove plate, 52_ first sliding block, 53_ rotating column, 54_ groove ring, 55_ first guide rod, 56_ feeding pipe, 6_ clamping mechanism, 61_ groove block, 62_ clamping block, 63_ screw rod, 64_ thread tooth block, 7_ locking mechanism, 71_ guide plate, 72_ rotating shaft, 73_ rotating disc, 74_ column gear, 75_ rack, 8_ drying mechanism, 81_ second groove plate, 82_ second sliding block, 83_ hot drier, 84_ second guide rod, 9_ protection mechanism, 91_ third groove plate, 92_ protection plate, 93_ rod and 94_ limiting block.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

Example 1

The utility model provides a PCB circuit board three proofings lacquer painting equipment, as shown in fig. 1-7, including shell 1, stand 2, spout glassware 3, tilting mechanism 4, spraying mechanism 5 and clamping mechanism 6, 1 outer bottom interval rigid coupling of shell has four stands 2, be provided with tilting mechanism 4 on the shell 1, tilting mechanism 4 can realize providing power and drive the PCB board and rotate, is provided with spraying mechanism 5 between shell 1 and the tilting mechanism 4, is provided with on the spraying mechanism 5 and spouts glassware 3, spouts glassware 3 can realize lacquering to the PCB board, spraying mechanism 5 can realize driving spout glassware 3 removes, is provided with clamping mechanism 6 on tilting mechanism 4, and clamping mechanism 6 can realize pressing from both sides tightly spacing to the PCB board.

As shown in fig. 1-4, the turnover mechanism 4 includes a dual-axis motor 41, a rotating rod 42 and a material placing plate 43, the dual-axis motor 41 is fixed in the middle of the outer bottom of the housing 1, the rotating rod 42 is rotatably disposed in the middle of the left and right sides of the housing 1, the output shafts of the left and right sides of the dual-axis motor 41 are respectively in synchronous belt transmission with the rotating rod 42 of the left and right sides, and the material placing plate 43 is fixed between the rotating rod 42 of the left and right sides.

As shown in fig. 1, 5 and 6, the spraying mechanism 5 includes a first slot plate 51, a first slider 52, a rotating column 53, a slot ring 54, a first guide rod 55 and a feeding pipe 56, the first slot plate 51 is fixedly connected to the upper middle portions of the left and right sides in the housing 1, the first slider 52 is slidably arranged in the left and right first slot plates 51, the rotating column 53 is rotatably arranged on the left and right first sliders 52, the left and right rotating columns 53 are fixedly connected to the sprayer 3, the first guide rod 55 is fixedly connected to the bottom of the left and right rotating column 53, the left and right first guide rods 55 are respectively located in the left and right slot rings 54, the left and right first guide rods 55 are respectively slidably connected to the left and right slot rings 54, the left and right sides of the sprayer 3 are respectively connected to the feeding pipe 56, the left and right feeding pipes 56 are both fixedly connected to the housing 1, and the feeding pipe 56 is made of rubber.

As shown in fig. 2, 3 and 7, the clamping mechanism 6 includes a groove block 61, a clamping block 62, a screw 63 and a thread tooth block 64, the top of the discharging plate 43 is fixedly connected with four groove blocks 61 at intervals, the clamping blocks 62 are slidably arranged in the four groove blocks 61, the upper parts of the four groove blocks 61 are all connected with the screw 63 in a threaded manner, the bottom ends of the four screw 63 are respectively fixedly connected with the four clamping blocks 62, and the lower parts of the four screw 63 are all connected with the thread tooth block 64 in a threaded manner.

Firstly, an operator connects the feeding plates 43 on the left and right sides with a feeding pipe, then places the PCB on the feeding plates 43, respectively twists four screw tooth blocks 64 to rotate forward, the four screw tooth blocks 64 rotate forward to respectively drive four screw rods 63 to move downward, the four screw rods 63 move downward to respectively drive four clamping blocks 62 to move downward, the four clamping blocks 62 move downward to clamp and limit the PCB, the double-shaft motor 41 and the material sprayer 3 are started to work, the double-shaft motor 41 respectively drives the rotating rods 42 on the left and right sides to rotate through synchronous belt transmission, the rotating rods 42 on the left and right sides drive the feeding plates 43 to rotate, the feeding plates 43 also drive the slotted rings 54 on the left and right sides to rotate, the slotted rings 54 on the left and right sides respectively drive the first guide rods 55 on the left and right sides to move upward and downward, the first guide bar 55 in the left and right sides reciprocates and drives the left and right sides respectively and rotates post 53 and reciprocates, the left and right sides rotates post 53 and reciprocates and drives and spouts glassware 3 and reciprocate, 3 blowout three proofings of glassware spout are painted the processing to the PCB board afterwards, and simultaneously, blowing board 43 rotates and still drives the PCB board and rotates, the PCB board rotates and makes the three proofings of lacquer more even by the japanning, so relapse, can constantly be to the even japanning of PCB board, work efficiency is high, after the completion of the painting of PCB board, close biax motor 41 and spout glassware 3, biax motor 41 stops to drive left and right sides dwang 42 respectively through synchronous belt drive and rotates, the PCB board just also stops rotating, and spout glassware 3 just stop reciprocating, twist four screw tooth pieces 64 reversal according to the above-mentioned operation again, four clamp splice 62 just also upwards move and stop spacing to the PCB board, take off the PCB board and carry out subsequent processing.

Example 2

On the basis of embodiment 1, as shown in fig. 2, 8 and 9, the device further includes a locking mechanism 7, the locking mechanism 7 includes a guide plate 71, a rotating shaft 72, a rotating disc 73, a column gear 74 and racks 75, the guide plate 71 is fixedly connected to the top of the material placing plate 43 in a left-right symmetrical manner, the rotating shafts 72 are rotatably arranged on the inner sides of the left and right guide plates 71, the rotating discs 73 are fixedly connected to the upper portions of the left and right rotating shafts 72, the column gears 74 are fixedly connected to the lower portions of the left and right rotating shafts 72, the racks 75 are slidably arranged on the upper portions of the four slot blocks 61, the left two racks 75 are engaged with the left column gear 74, the right two racks 75 are engaged with the right column gear 74, and the four racks 75 are respectively engaged with the threaded tooth blocks 64.

As shown in fig. 2 and 10, the drying device 8 further includes a drying mechanism 8, the drying mechanism 8 includes a second slot plate 81, a second slider 82, a thermal dryer 83 and a second guide rod 84, the second slot plate 81 is fixedly connected to the middle lower portion of the left and right side surfaces in the housing 1, the second slider 82 is slidably disposed in the left and right side second slot plates 81, the thermal dryer 83 is fixedly connected between the left and right side second sliders 82, the thermal dryer 83 can dry and cure the three-proofing paint, the second guide rods 84 are fixedly connected to the top portions of the left and right side second sliders 82, the left and right side second guide rods 84 are respectively located in the left and right side slot rings 54, and the left and right side second guide rods 84 are respectively slidably connected to the left and right side slot rings 54.

As shown in fig. 1 and 11, still including protection machanism 9, protection machanism 9 is including third frid 91, protection plate 92, bow-shaped pole 93 and stopper 94, the outer front and back both sides face of shell 1 all bilateral symmetry rigid coupling has third frid 91, the slidingtype is equipped with protection plate 92 between the third frid 91 of the place ahead left and right sides, three proofings of lacquer splashes when protection plate 92 can realize the japanning, upper portion all the rotary type is equipped with bow-shaped pole 93 in front and back both sides protection plate 92, upper portion all the rigid coupling has stopper 94 in the outer front side face of shell 1, left and right sides stopper 94 contacts with left and right sides bow-shaped pole 93 respectively.

When a PCB is placed on the placing plate 43, the left and right turntables 73 are respectively twisted to rotate forwards, the left and right turntables 73 rotate forwards to respectively drive the left and right rotary shafts 72 to rotate forwards, the left and right rotary shafts 72 rotate forwards to respectively drive the left and right column gears 74 to rotate forwards, the left and right column gears 74 rotate forwards to respectively drive the four racks 75 to move inwards, the four racks 75 move inwards to respectively drive the four threaded tooth blocks 64 to rotate forwards, the four threaded tooth blocks 64 rotate forwards to respectively drive the four screw rods 63 to move downwards, the four screw rods 63 move downwards to respectively drive the four clamping blocks 62 to move downwards, the four clamping blocks 62 move downwards to clamp and limit the PCB, after painting of the PCB is completed, the left and right turntables 73 are respectively twisted to rotate backwards according to the operation, the four clamping blocks 62 also move upwards to reset to stop clamping and limit the PCB, and thus the clamping blocks 62 can synchronously move.

When the PCB is painted, the heat dryer 83 is started to work, then the left and right groove rings 54 rotate to respectively drive the left and right second guide rods 84 to move up and down, the second guide rods 84 move up and down to respectively drive the left and right second sliding blocks 82 to move up and down, the left and right second sliding blocks 82 move up and down to drive the heat dryer 83 to move up and down, the heat dryer 83 moves up and down to dry the PCB quickly and uniformly, after the PCB is painted, the heat dryer 83 is closed to work, the left and right groove rings 54 respectively stop driving the left and right second sliding blocks 82 to move up and down through the left and right second guide rods 84, the heat dryer 83 stops moving up and down, and therefore the PCB after being painted can be dried quickly.

When painting on the PCB, both sides guard plate 92 can avoid the in-process three proofings of lacquer to sputter on the operating personnel, influence health safety around, after the completion of the painting on the PCB, both sides bow-shaped rod 93 rotates respectively and breaks away from with both sides stopper 94 around with around the pulling, because of the effect of gravity, both sides guard plate 92 downstream around, people can take out the PCB and carry out subsequent processing afterwards, the PCB takes out the back, both sides guard plate 92 rebound resets around the pulling, both sides bow-shaped rod 93 rotates respectively around with on both sides stopper 94 around, so, can avoid three proofings to sputter to the operating personnel on one's body, influence health safety.

The technical principles of the embodiments of the present invention have been described above with reference to specific embodiments. The description is only intended to explain the principles of embodiments of the invention and should not be taken in any way as limiting the scope of the embodiments of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive step, and these embodiments will fall within the scope of the present invention.

Claims

1. The utility model provides a PCB circuit board three proofings lacquer painting equipment, including shell (1), stand (2) and spout glassware (3), and double-layered material mechanism (6), shell (1) outer bottom interval rigid coupling has four stands (2), spouts glassware (3) and is used for lacquering to the PCB board, a serial communication port, still including tilting mechanism (4) and spraying mechanism (5), be provided with on shell (1) and be used for providing power to drive PCB board pivoted tilting mechanism (4), be provided with between shell (1) and tilting mechanism (4) spraying mechanism (5), spraying mechanism (5) and spout glassware (3) fixed connection, spraying mechanism (5) are used for driving spout glassware (3) and remove.

2. The three-proofing paint coating equipment for the PCB according to claim 1, further comprising a material clamping mechanism (6), wherein the turnover mechanism (4) is provided with the material clamping mechanism (6) for clamping and limiting the PCB.

3. The three-proofing paint coating equipment for the PCB circuit board according to claim 2, wherein the turnover mechanism (4) comprises a double-shaft motor (41), a rotating rod (42) and a material placing plate (43), the double-shaft motor (41) is fixedly connected to the middle of the outer bottom of the shell (1), the rotating rod (42) is rotatably arranged in the middle of the left side and the right side of the shell (1), output shafts of the left side and the right side of the double-shaft motor (41) are respectively in synchronous belt transmission with the rotating rod (42) of the left side and the right side, and the material placing plate (43) is fixedly connected between the rotating rod (42) of the left side and the right side.

4. The three-proofing paint coating device for the PCB circuit boards according to claim 3, wherein the spraying mechanism (5) comprises a first groove plate (51), a first sliding block (52), a rotating column (53), a groove ring (54), a first guide rod (55) and a feeding pipe (56), the first groove plate (51) is fixedly connected to the middle upper portion of the left side surface and the middle upper portion of the right side surface in the shell (1), the first sliding block (52) is slidably arranged in the first groove plate (51) on the left side and the right side, the rotating column (53) is rotatably arranged on the first sliding block (52) on the left side and the right side, the rotating column (53) on the left side and the right side is fixedly connected with the material sprayer (3), the first guide rod (55) on the left side and the right side is fixedly connected to the bottom of the rotating column (53) on the left side and the right side, the first guide rod (55) on the left side and the right side are respectively located in the groove ring (54) on the left side and the right side, the first guide rod (55) on the left side and the right side are respectively slidably connected to the groove ring (54), the feeding pipe (56) on the left side and the left side, and the shell (1) is fixedly connected with the feeding pipe (56).

5. The three-proofing paint coating equipment for the PCB circuit boards according to claim 4, wherein the clamping mechanism (6) comprises groove blocks (61), clamping blocks (62), screws (63) and thread tooth blocks (64), the top of the discharging plate (43) is fixedly connected with four groove blocks (61) at intervals, the clamping blocks (62) are arranged in the four groove blocks (61) in a sliding mode, the upper portions of the four groove blocks (61) are in threaded connection with the screws (63), the bottom ends of the four screws (63) are fixedly connected with the four clamping blocks (62) respectively, and the lower portions of the four screws (63) are in threaded connection with the thread tooth blocks (64).

6. The three-proofing paint coating device for the PCB according to claim 5, further comprising a locking mechanism (7) for synchronously operating the clamping blocks (62), wherein the locking mechanism (7) comprises a guide plate (71), a rotating shaft (72), a turntable (73), a column gear (74) and racks (75), the guide plate (71) is fixedly connected to the top of the discharging plate (43) in a bilateral symmetry manner, the rotating shaft (72) is rotatably arranged on the inner sides of the guide plates (71) on the left side and the right side, the turntable (73) is fixedly connected to the upper portions of the rotating shafts (72) on the left side and the right side, the column gear (74) is fixedly connected to the lower portions of the rotating shafts (72) on the left side and the right side, the racks (75) are slidably arranged on the upper portions of the four groove blocks (61), the left two racks (75) are meshed with the column gear (74), the right two racks (75) are meshed with the right column gear (74), and the four racks (75) are respectively meshed with the threaded tooth blocks (64).

7. The PCB three-proofing paint coating equipment according to claim 6, further comprising a drying mechanism (8) for drying and curing three-proofing paint, wherein the drying mechanism (8) comprises a second groove plate (81), a second sliding block (82), a heat dryer (83) and a second guide rod (84), the second groove plate (81) is fixedly connected to the middle lower portion of the left side surface and the middle lower portion of the right side surface in the shell (1), the second sliding blocks (82) are slidably arranged in the second groove plates (81) on the left side and the right side, the heat dryer (83) for drying and curing the three-proofing paint is fixedly connected between the second sliding blocks (82) on the left side and the right side, the second guide rods (84) on the left side and the right side are fixedly connected to the tops of the second sliding blocks (82) on the left side and the right side, the second guide rods (84) on the left side and the right side are respectively located in the groove rings (54) on the left side and the right side, and the second guide rods (84) on the left side are respectively slidably connected to the groove rings (54) on the left side and the right side.

8. The three-proofing paint coating equipment for the PCB circuit board according to claim 7, further comprising a protection mechanism (9) used for avoiding three-proofing paint splashing, wherein the protection mechanism (9) comprises a third groove plate (91), a protection plate (92), an arc-shaped rod (93) and a limiting block (94), the outer front side surface and the outer rear side surface of the shell (1) are fixedly connected with the third groove plate (91) in a bilateral symmetry mode, the protection plate (92) used for avoiding three-proofing paint splashing is arranged between the third groove plate (91) on the left side and the right side in the front direction in a sliding mode, the middle upper portions of the protection plates (92) on the front side and the rear side in a rotary mode are provided with the arc-shaped rod (93), the middle upper portions of the outer front side surface of the shell (1) are fixedly connected with the limiting block (94), and the limiting blocks (94) on the left side and the right side are respectively in contact with the arc-shaped rod (93) on the left side and the right side.