阅读说明：本技术 一种工程造价用招标指示装置 (Engineering cost is with inviting mark indicating device ) 是由 不公告发明人 于 2021-01-13 设计创作，主要内容包括：本发明涉及工程招标辅助设备技术领域,具体公开了一种工程造价用招标指示装置；包括底部U型架和展示框架,底部U型架的左右两端上表面均固定设置有导轨条,底部U型架的后端设置有第一电机,第一电机的输出轴上连接有转轴,转轴上前后设置有第一主动带轮和第二主动带轮,两个滑动空腔中分别设置有第一丝杠和第二丝杠,展示框架左右两端均连接有竖条,展示框架的内部开设有切换内腔,切换内腔中设置有第一滑轨和第二滑轨；本发明通过万向轮的设置能够便于整个装置的挪动,其使用方便,通过第一电机的驱动作用实现整个展示框架的平躺和立起,其能够在不使用时能够快速将整个展示框架收纳在底部U型架上,其体积小、收纳方便、实用性强。(The invention relates to the technical field of engineering bid inviting auxiliary equipment, and particularly discloses a bid inviting indicating device for engineering cost; the display frame comprises a bottom U-shaped frame and a display frame, wherein guide rail strips are fixedly arranged on the upper surfaces of the left end and the right end of the bottom U-shaped frame, a first motor is arranged at the rear end of the bottom U-shaped frame, an output shaft of the first motor is connected with a rotating shaft, a first driving belt wheel and a second driving belt wheel are arranged on the rotating shaft in a front-back mode, a first lead screw and a second lead screw are respectively arranged in two sliding cavities, vertical strips are connected to the left end and the right end of the display frame, a switching inner cavity is formed in the display frame, and a first slide rail and a second slide rail are arranged in; the display frame can be conveniently moved by the arrangement of the universal wheels, is convenient to use, can be horizontally laid and vertically erected by the driving action of the first motor, can be quickly stored on the U-shaped frame at the bottom when not used, and is small in size, convenient to store and high in practicability.)

1. The utility model provides a construction cost is with inviting mark indicating device which characterized in that, includes bottom U type frame (1) and display frame (2), the lower surface of bottom U type frame (1) evenly is provided with a plurality of universal wheels (101).

2. The bidding indicating device for construction cost according to claim 1, wherein the upper surfaces of the left and right ends of the bottom U-shaped frame (1) are fixedly provided with guide rail bars (102), the guide rail bars (102) are provided with sliding cavities, the upper surface of the guide rail bars (102) is provided with strip-shaped sliding openings (103) of the sliding cavities, each sliding cavity is provided with a sliding block (104), the front and back side surfaces of the sliding block (104) are provided with threaded holes, and the upper surface of the sliding block (104) is connected with a triangular hinged plate (105) extending out of the strip-shaped sliding openings (103); a first motor (106) is fixedly arranged in the middle of the upper surface of the rear end of the bottom U-shaped frame (1), an output shaft of the first motor (106) is connected with a rotating shaft, a first driving pulley (107) and a second driving pulley (108) are arranged on the rotating shaft in the front and at the back, a first lead screw (109) and a second lead screw (110) are respectively arranged in the two sliding cavities, the front ends of the first lead screw (109) and the second lead screw (110) are respectively and rotatably connected with a bearing (111) on the front side wall of the sliding cavity, a bearing seat (112) is respectively arranged on the bottom U-shaped frame (1) at the rear side of each guide rail bar (102), the rear side surfaces of the guide rail bars (102) where the rear ends of the first lead screw (109) and the second lead screw (110) extend are rotatably connected with the bearing seats (112), and the rear ends of the first lead screw (109) and the second lead screw (110) are respectively connected with a first driven pulley (113) and a second driven pulley (114), the first driven pulley (113) and the second driven pulley (114) are arranged at intervals in the front-back direction, a first transmission belt (115) is arranged between the first driving pulley (107) and the first driven pulley (113), and a second transmission belt (116) is arranged between the second driving pulley (108) and the second driven pulley (114); the left end and the right end of the lower surface of the display frame (2) are connected with vertical bars (201), the lower ends of the vertical bars (201) are provided with rotating grooves capable of being inserted into the triangular hinged plates (105), a rotating pin shaft (117) is connected between the lower ends of the vertical bars (201) and the triangular hinged plates (105), transverse bars (118) are arranged on the upper surface of the bottom U-shaped frame (1) on the rear side of the first motor (106), the left end surface and the right end surface of each transverse bar (118) are rotatably connected with an L-shaped rotating bar (119), and a convex shaft (120) is rotatably connected between the upper end of each L-shaped rotating bar (119) and the middle of the left side surface and the right side surface of the display; a switching inner cavity (202) is formed in the display frame (2), a rectangular opening (203) is formed in the front side face of the left end of the display frame (2), a first sliding rail (204) and a second sliding rail (205) are fixedly arranged at the front end and the rear end of the bottom wall of the switching inner cavity (202) respectively, a first writing board (206) is arranged in the first sliding rail (204), a second writing board (207) is arranged in the second sliding rail (205), balls are movably arranged on the lower surfaces of the first writing board (206) and the second sliding rail (205), a first rack (208) is arranged on the rear side face of the upper end of the first writing board (206), a second rack (209) is arranged on the front side face of the upper end of the second writing board (207), a vertical shaft (210) is rotatably connected to the middle section of the top wall of the switching inner cavity (202), and a gear (211) is connected to the lower end of the vertical shaft (210), the front tooth surface and the rear tooth surface of the gear (211) are respectively meshed with the first rack (208) and the second rack (209); the blackboard-writing automatic cleaning device comprises a display screen (212) arranged at the upper end of the front side face of a display frame (2) on the right side of a rectangular opening (203), a control host (213) fixedly arranged on the front side face of the display frame (2) below the display screen (212), an operation knob (214) and a plurality of operation buttons (215) arranged on the front side face of the control host (213), a data transmission interface (216) arranged at the upper end of the right side face of the control host (213), loudspeakers (217) arranged at the lower ends of the left side face and the right side face of the control host (213), an blackboard-writing automatic cleaning device (3) arranged in a switching inner cavity (202) on the right side of the rectangular opening (203), wherein the blackboard-writing automatic cleaning device (3) comprises a second motor (301), a U-shaped moving strip (302) and a vertical lead screw (303), and the second motor (301) is fixedly arranged at the right end, vertical lead screw (303) rotate and set up the right-hand member in switching inner chamber (202), second motor (301) are stretched into and are switched in inner chamber (202) and are connected with the upper end of vertical lead screw (303), the interlude of U type removal strip (302) is provided with screw nut (304) with vertical lead screw (303) matched with, the trailing flank at the front and back both ends of U type removal strip (302) all is provided with brush hair (305) that contact respectively with first clipboard (206), second clipboard (207) leading flank.

3. The bidding indicating device for construction cost according to claim 2, wherein the left end of the front side of the U-shaped moving strip (302) is provided with a limit dovetail slider (306), and the inner wall of the front side of the middle section of the switching inner cavity (202) is provided with a vertical limit sliding groove (307) matched with the limit dovetail slider (306).

4. A bid indicator for construction costs according to claim 3, wherein a dust discharge port (308) is formed in a lower surface of the display frame (2) directly below the U-shaped moving bar (302).

5. The bidding indicator for construction cost according to claim 2, wherein the number of the universal wheels (101) provided on the lower surface of the bottom U-shaped frame (1) is four, and the universal wheels are respectively provided on four corners of the lower surface of the bottom U-shaped frame (1).

Technical Field

The invention relates to the technical field of engineering bid inviting auxiliary equipment, and particularly discloses a bid inviting indicating device for engineering cost.

Background

The project cost refers to the construction price of the project, and refers to the total sum of the expected or actual costs of bai to complete the construction of one project. The project cost, defined from the perspective of the owner (investor), refers to the construction cost of the project, i.e., the total capital investment cost expected or actually paid for constructing a project. On the site of the project cost bidding, various auxiliary devices are required to be used for the bidding process.

The invention with the application number of CN110060613A discloses a building engineering bidding device, which comprises a device base, wherein the left side of the top of the device base is fixedly connected with a supporting shell, the top of the supporting shell is fixedly connected with a bidding plate body, the front end of the left side of the bidding plate body is fixedly connected with a first door spindle, the front side of the first door spindle is movably connected with a baffle, the right end of the front side of the baffle is welded with a first handle, the rear side of the baffle is provided with a first groove, and the top of the right side of the first groove is fixedly connected with a first motor. According to the invention, through the cleaning shell in the first groove, the threaded rod in the cleaning shell, the second motor and the blowing fan blade in the fixed shell, after the signboard moving device is used and the baffle is closed, the writing board, the display screen and the board surface on the signboard moving board body can be cleaned by using the cleaning bristles on the cleaning shell, and the dust in the second groove can be blown up in the cleaning process, and then the cleaning bristles are used for cleaning the dust, so that the manual and manual cleaning of the signboard moving device is omitted. Although its function of this building engineering device of tendering is various, can clean clipboard and display screen automatically, but it is because alone going on when different units in the process cost tendering process, consequently need keep secret to relevant information on the clipboard, and whole scene of tendering is tender the unit more, just can carry out next unit and tenders the tender process after the information on the clipboard is erased at every turn, and it has delayed going on of whole tender process. In addition, the overall structure of the building engineering bidding device is large, subsequent storage and storage are not convenient, and the whole device is inconvenient to move. Therefore, aiming at the defects of the existing mark-drawing device for construction engineering, the mark-drawing indicating device for construction cost is designed, which can keep secret and automatically clear information on a writing board and is convenient for storage and movement of the whole device.

Disclosure of Invention

The invention aims to design a bidding indicating device for engineering cost, which can keep secret and automatically clear information on a writing board and is convenient to store and move the whole device, aiming at the defects of the existing bidding device for the construction engineering.

The invention is realized by the following technical scheme:

a bid indicator for engineering cost comprises a bottom U-shaped frame and a display frame, wherein a plurality of universal wheels are uniformly arranged on the lower surface of the bottom U-shaped frame, guide rail strips are fixedly arranged on the upper surfaces of the left end and the right end of the bottom U-shaped frame, sliding cavities are formed in the guide rail strips, strip-shaped sliding openings of the sliding cavities are formed in the upper surfaces of the guide rail strips, sliding blocks are arranged in the sliding cavities, penetrating threaded holes are formed in the front side surface and the rear side surface of each sliding block, and the upper surfaces of the sliding blocks are connected with triangular hinged plates extending out of the strip-shaped sliding openings;

a first motor is fixedly arranged in the middle of the upper surface of the rear end of the bottom U-shaped frame, a rotating shaft is connected to an output shaft of the first motor, a first driving belt wheel and a second driving belt wheel are arranged on the front portion and the rear portion of the rotating shaft, a first lead screw and a second lead screw are respectively arranged in the two sliding cavities, the front ends of the first lead screw and the second lead screw are respectively and rotatably connected with a bearing on the front side wall of the sliding cavity, a bearing seat is respectively arranged on the bottom U-shaped frame on the rear side of each guide rail bar, the rear ends of the first lead screw and the second lead screw are respectively extended to the rear side surface of the guide rail bar and rotatably connected with the bearing seat, a first driven belt wheel and a second driven belt wheel are respectively connected to the rear ends of the first lead screw and the second lead screw, the first driven belt wheel and the second driven belt wheel are arranged at intervals in the front portion and the rear portion, and a first transmission, a second transmission belt is arranged between the second driving belt wheel and the second driven belt wheel;

the left end and the right end of the lower surface of the display frame are both connected with vertical bars, the lower ends of the vertical bars are provided with rotating grooves capable of being inserted into the triangular hinged plates, rotating hinge pins are connected between the lower ends of the vertical bars and the triangular hinged plates, transverse bars are arranged on the upper surface of the U-shaped frame at the bottom of the rear side of the first motor, the left end surface and the right end surface of each transverse bar are rotatably connected with L-shaped rotating bars, and the upper ends of the L-shaped rotating bars and the middle parts of the left side surface and the right side surface of the display frame are rotatably;

a switching inner cavity is formed in the display frame, a rectangular opening is formed in the front side face of the left end of the display frame, a first slide rail and a second slide rail are fixedly arranged at the front end and the rear end of the bottom wall of the switching inner cavity respectively, a first writing board is arranged in the first slide rail, a second writing board is arranged in the second slide rail, balls are movably arranged on the lower surfaces of the first writing board and the second slide rail respectively, a first rack is arranged on the rear side face of the upper end of the first writing board, a second rack is arranged on the front side face of the upper end of the second writing board, a vertical shaft is rotatably connected to the middle section of the top wall of the switching inner cavity, the lower end of the vertical shaft is connected with a gear, and the front tooth face and the rear tooth face of the gear are meshed with the;

the display device comprises a rectangular opening, a display screen is arranged at the upper end of the front side face of a display frame on the right side of the rectangular opening, a control host is fixedly arranged on the front side face of the display frame below the display screen, an operation knob and a plurality of operation buttons are arranged on the front side face of the control host, a data transmission interface is arranged at the upper end of the right side face of the control host, and loudspeakers are arranged at the lower ends of the left side face and the right side face of the control host.

As a further arrangement of the scheme, an automatic blackboard-writing cleaning device is arranged in the switching inner cavity on the right side of the rectangular opening.

As a further arrangement of the above scheme, the blackboard-writing automatic cleaning device comprises a second motor, a U-shaped moving strip and a vertical screw rod, the second motor is fixedly arranged at the right end of the upper surface of the display frame, the vertical screw rod is rotatably arranged at the right end of the switching inner cavity, the second motor extends into the switching inner cavity and is connected with the upper end of the vertical screw rod, a screw nut matched with the vertical screw rod is arranged at the middle section of the U-shaped moving strip, and the rear side faces of the front end and the rear end of the U-shaped moving strip are respectively provided with brush hair which is respectively contacted with the front side faces of the first writing plate and the second writing plate.

As a further arrangement of the scheme, the left end of the front side face of the U-shaped moving strip is provided with a limiting dovetail slide block, and a vertical limiting sliding groove matched with the limiting dovetail slide block is formed in the inner wall of the front side of the middle section of the switching inner cavity.

As a further arrangement of the above scheme, a dust discharge port is formed in the lower surface of the display frame located right below the U-shaped moving strip.

As the further arrangement of the scheme, the number of the universal wheels arranged on the lower surface of the bottom U-shaped frame is four, and the universal wheels are respectively arranged at four corners of the lower surface of the bottom U-shaped frame.

As a further arrangement of the scheme, the universal wheel is further provided with a foot brake.

As a further arrangement of the above scheme, a data reading module and a data storage module are arranged inside the control host.

As a further arrangement of the scheme, a dustproof roller shutter is arranged on the front side surface of the display frame above the display screen.

As a further arrangement of the scheme, the length of the display frame is 2-2.4 m, and the height of the display frame is 1.2-1.6 m.

Has the advantages that:

1) the bid-calling indicating device for the construction cost can be convenient for moving the whole device through the arrangement of the universal wheels, and is convenient to use; in addition, through starting the first motor, the flat lying and the standing of the whole display frame can be realized through the cooperation of the first lead screw, the second lead screw and the sliding block, the whole display frame can be rapidly stored on the U-shaped frame at the bottom when the display frame is not used, and the display frame is small in size, convenient to store and high in practicability.

2) According to the bid inviting indicating device for engineering cost, the left end and the right end of the front side surface of the display frame are respectively provided with the writing board and the display screen, the display screen can play electronic documents, meanwhile, the writing board can be used for writing bid inviting related information during engineering cost bidding, and the bid inviting indicating device for engineering cost has various functions; in addition, its clipboard divide into first clipboard and second clipboard, and its first clipboard and second clipboard can realize the fast switch-over through promoting, can the fast switch-over clipboard at the bidding scene, prevent that last bidder's relevant information from revealing, and its privacy security is strong.

3) The display frame is also provided with the blackboard writing automatic cleaning device, and the U-shaped moving strip is driven by the second motor to move up and down, so that the contents stored in the switching inner cavity on the writing board can be cleaned, and the blackboard writing automatic cleaning device is convenient to use and high in functionality.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of a first angular perspective structure of the present invention;

FIG. 2 is a schematic view of a second angular perspective structure according to the present invention;

FIG. 3 is a schematic perspective view of the present invention during storage;

FIG. 4 is a schematic perspective view of the bottom U-shaped frame, guide rail bar, etc. of the present invention;

FIG. 5 is a schematic perspective view of a first motor, a sliding block, a first lead screw, and the like according to the present invention;

FIG. 6 is a perspective view of a display frame according to the present invention;

FIG. 7 is a schematic perspective view of the first writing board, the second writing board, etc. of the present invention;

FIG. 8 is an enlarged perspective view of FIG. 7 in accordance with the present invention;

FIG. 9 is an interior plan view of the display frame of the present invention;

fig. 10 is a schematic perspective view of an automatic blackboard-writing cleaning device according to the present invention.

Wherein, 1-bottom U-shaped frame, 101-a plurality of universal wheels, 102-guide rail bars, 103-bar-shaped sliding openings, 104-sliding blocks, 105-triangular hinged plates, 106-first motors, 107-first driving pulleys, 108-second driving pulleys, 109-first lead screws, 110-second lead screws, 111-bearings, 112-bearing seats, 113-first driven pulleys, 114-second driven pulleys, 115-first transmission belts, 116-second transmission belts, 117-rotating pin shafts, 118-transverse bars, 119-L-shaped rotating bars and 120-convex shafts;

2-display frame, 201-vertical bar, 202-switching inner cavity, 203-rectangular port, 204-first sliding rail, 205-second sliding rail, 206-first writing board, 207-second writing board, 208-first rack, 209-second rack, 210-vertical shaft, 211-gear, 212-display screen, 213-control host, 214-operation knob, 215-operation button, 216-data transmission interface, 217-loudspeaker;

3-blackboard-writing automatic cleaning device, 301-second motor, 302-U-shaped moving strip, 303-vertical screw rod, 304-screw rod nut, 305-brush hair, 306-limiting dovetail slide block, 307-vertical limiting sliding groove and 308-dust discharging port

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but 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 application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail with reference to the accompanying drawings 1 to 10, in conjunction with the embodiments.

Example 1

Embodiment 1 introduces a tender indicating device for construction cost, refer to fig. 1, fig. 2 and fig. 3, and its major structure includes bottom U-shaped frame 1 and display frame 2, evenly is provided with a plurality of universal wheels 101 at the lower surface of bottom U-shaped frame 1, and its universal wheels 101 that set up at bottom U-shaped frame 1 lower surface are four when specifically setting up, and set up respectively in four corners of bottom U-shaped frame 1 lower surface to in order to have the fixed action to universal wheel 101, still be provided with the service brake (not drawn in the figure) on every universal wheel 101.

Referring to fig. 4 and 5, guide rail strips 102 are fixedly arranged on the upper surfaces of the left end and the right end of the bottom U-shaped frame 1, a sliding cavity is arranged in each guide rail strip 102, a strip-shaped sliding opening 103 of the sliding cavity is formed in the upper surface of each guide rail strip 102, a sliding block 104 matched with each sliding cavity is arranged in each sliding cavity, threaded holes penetrating through the sliding blocks 104 are formed in the front side and the rear side of each sliding cavity, and a triangular hinged plate 105 extending out of the strip-shaped sliding opening 103 is connected to the upper surface of each sliding block 104.

A first motor 106 is fixedly arranged at the middle position of the upper surface of the rear end of the bottom U-shaped frame 1, an output shaft of the first motor 106 is connected with a rotating shaft (not labeled in the figure), a first driving pulley 107 and a second driving pulley 108 are arranged on the rotating shaft in the front and at the back, a first lead screw 109 and a second lead screw 110 are respectively arranged in the two sliding cavities, the front ends of the first lead screw 109 and the second lead screw 110 are rotatably connected with a bearing 111 on the front side wall of the sliding cavity, a bearing seat 112 is arranged on the bottom U-shaped frame 1 at the rear side of each guide rail bar 102, and the rear side surfaces of the guide rail bars 102, where the rear ends of the first lead screw 109 and the second lead screw 110 extend, are rotatably connected with the bearing seats 112. A first driven pulley 113 and a second driven pulley 114 are connected to the rear ends of the first lead screw 109 and the second lead screw 110, respectively, and the first driven pulley 113 and the second driven pulley 114 are spaced forward and backward. A first transmission belt 115 is provided between the first driving pulley 107 and the first driven pulley 113, and a second transmission belt 116 is provided between the second driving pulley 108 and the second driven pulley 114.

Referring to fig. 1, fig. 3 and fig. 5, vertical bars 201 are connected to both ends about the lower surface of the display frame 2, a rotation groove capable of being inserted into the triangular hinged plate 105 is formed in the lower end of each vertical bar 201, a rotation pin shaft 117 is connected between the lower end of each vertical bar 201 and the triangular hinged plate 105, a transverse bar 118 is arranged on the upper surface of the bottom U-shaped frame 1 behind the first motor 106, L-shaped rotation bars 119 are rotatably connected to both ends of the transverse bar 118, and a protruding shaft 120 is rotatably connected between the upper end of each L-shaped rotation bar 119 and the middle of each of the left and right sides of the display frame 2. The two lead screws are driven by the first motor 106 to rotate, then the lead screws are matched with the threaded holes on the sliding block 104, so that the sliding block 104 moves back and forth along the sliding cavity, and then the display frame 2 can be accommodated and erected through the left and right sides of the L-shaped rotating strip 119.

Referring to fig. 6, 7, 8 and 9, the length of the display frame 2 in the present embodiment is 2 to 2.4m, and the height of the display frame 2 is 1.2 to 1.6 m. A switching cavity 202 is formed inside the display frame 2, and a rectangular opening 203 is formed in the front side surface of the left end of the display frame 2. A first slide rail 204 and a second slide rail 205 are respectively and fixedly arranged at the front end and the rear end of the bottom wall of the switching inner cavity 202, a first writing board 206 is arranged in the first slide rail 204, a second writing board 207 is arranged in the second slide rail 205, and balls (not shown in the figure) are movably arranged on the lower surfaces of the first writing board 206 and the second slide rail 205, and the arrangement of the balls can reduce the resistance of the first writing board 206 and the second slide rail 205 when sliding in the first slide rail 204 and the second slide rail 205. A first rack 208 is provided on the upper rear side of the first writing board 206, and a second rack 209 is provided on the upper front side of the second writing board 207. A vertical shaft 210 is rotatably connected to the middle section of the top wall of the switching chamber 202, a gear 211 is connected to the lower end of the vertical shaft 210, and the front and rear tooth surfaces of the gear 211 are respectively engaged with the first rack 208 and the second rack 209. When one of the writing boards is moved, the gear 211 is driven to rotate, and then the gear 211 can drive the other writing board to move reversely, so that the two writing boards are switched rapidly.

The upper end of the front side of the display frame 2 at the right side of the rectangular opening 203 is provided with a display screen 212, and in order to protect the display screen 212 from dust, a dust-proof rolling curtain (not shown in the figure) is further arranged at the front side of the display frame 2 above the display screen 212. The front side of the display frame 2 under the display screen 212 is fixedly provided with a control host 213, and a data reading module and a data storage module (the data reading module and the data storage module are prior art and not described in detail herein) are provided inside the control host 213, and the data reading module and the data storage module can read and store bidding documents of bidders. An operation knob 214 and a plurality of operation buttons 215 are arranged on the front side of the control host 213, a data transmission interface 216 is arranged on the upper end of the right side of the control host 213, the data transmission interface 216 can be connected with a notebook computer or a USB flash disk, and speakers 217 are arranged on the lower ends of the left side and the right side of the control host 213.

Example 2

Embodiment 2 describes a construction cost bid indicator modified based on embodiment 1, and the same points as embodiment 1 are not described again, except that fig. 9, 10 and 3 are referred to.

In the embodiment 2, the blackboard-writing automatic cleaning device 3 is arranged in the switching inner cavity 202 positioned at the right side of the rectangular opening 203. Specifically, the blackboard writing automatic cleaning device 3 comprises a second motor 301, a U-shaped moving strip 302 and a vertical screw 303, the second motor 301 is fixedly arranged at the right end of the upper surface of the display frame 2, the vertical screw 303 is rotatably arranged at the right end of the switching inner cavity 202, the second motor 301 extends into the switching inner cavity 202 and is connected with the upper end of the vertical screw 303, a screw nut 304 matched with the vertical screw 303 is arranged in the middle section of the U-shaped moving strip 302, and the rear side surfaces of the front end and the rear end of the U-shaped moving strip 302 are respectively provided with bristles 305 contacted with the front side surfaces of the first writing board 206 and the second writing board 207. The vertical lead screw 303 is driven by the second motor 301 to rotate in the forward direction or in the reverse direction, so that the U-shaped moving strip 302 can move up and down in the switching inner cavity 202, and then the chalk fonts on the first blackboard writing 206 or the second blackboard writing 207 are automatically cleaned through the brush bristles 305.

In addition, this embodiment 2 still is provided with spacing dovetail slider 306 at the leading flank left end of U type removal strip 302, has seted up spacing dovetail slider 306 matched with vertical spacing spout 307 on the interlude front side inner wall of switching inner chamber 202, and the stability when U type removal strip 302 reciprocated can be guaranteed in the setting of its spacing dovetail slider 306 and vertical spacing spout 307 to guarantee its clean effect.

Finally, a dust discharge outlet 308 is formed in the lower surface of the display frame 2 located right below the U-shaped moving bar 302, and the dust discharge outlet 308 can automatically discharge the cleaned chalk dust.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.