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CLAIM OF PRIORITY  
       [0001]     This application claims priority under 35 U.S.C. §119 to PCT Application No. PCT/CN03/00918 filed Dec. 30, 2003, which is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention is related to a polisher for constructional fitting, in particular a polisher that may be used to polish walls and roofs and has self-leveling function.  
         [0004]     2. Description of the Related Art  
         [0005]     People usually do as follows during room fitting work: prepare plaster with emulsion and powder (e.g., calcium carbonate powder) and apply the plaster on the all; or polish the wall with a soft blade to form smooth wall; or polish the wall with sandpaper and then paint emulsion paint on the wall. Above polishing approaches have two characteristics: first, it achieves smooth wall face through polishing; second, it is carried out manually.  
         [0006]     The wall polisher described in a prior patent application (application No.: 00114111.2) of the inventor utilizes a rotary sandstone sliding along a rail to polish walls; though that wall polisher overcomes inconvenience of manual operation, it has to be refined further in actual application, for example, how to eliminate position difference between rails of different sizes, how to collect dust created during polishing work, and how to achieve self-leveling on surface being polishes to reduce job difficulty, etc.  
       SUMMARY OF THE INVENTION  
       [0007]     The purpose of this invention is to overcome defects in the existing apparatus and provide a polisher that has features including high stability, low vibration, self-leveling, and dust-absorption, and always sticks to the wall (roof) seamlessly during the polishing work to reduce job difficulty.  
         [0008]     To attain above purpose, this invention employs the following technical solution:  
         [0009]     The wall polisher provided in this invention mainly comprises a movable seat, an external motor on the seat, a plurality of rails mounted vertically on the seat and in parallel to each other, a built-in motor that can sliding along the rail, a sandstone cylinder driven by the built-in motor, and a suspension beam on the top of the rails.  
         [0010]     Said seat has an upright post; said rails are mounted on sliding plates, which are fitted over said upright post.  
         [0011]     Said sandstone cylinder has a protection hood, which has a positioning pulley at the side near the wall and an air outlet and a dust absorption mouth at bottom; said dust absorption mouth has a flat and long air inlet, a chamber connected to that air inlet, and hose outlets at both sides of the chamber; said hose outlets are connected to hoses of a dust collector; said dust absorption mouth is made of a soft rubber material; said protection hood of the sandstone cylinder has a baffle plate at bottom; a annular soft rubber dust pipe is fixed in said baffle plate.  
         [0012]     Said rails are made of unsaturated reinforced resin glass and comprise big, medium, and small rails connected to each other; the cross sections of the rails are rectangular with a notch at one side to enable the main shaft to slide up and down; the rails are connected to each other at front and rear sides against the wall.  
         [0013]     The rails on sliding plates are made of unsaturated reinforced resin glass and comprise big and small rails connected to each other; the cross section of said rails are in “□” shape with a notch on one side to enable the main shaft to sliding up and down; the rails are fixed to each other at front and rear sides against the wall. A position difference correction rail is devised among those rails to correct position difference between those rails; the inner diameter and outer diameter of said position difference correction rail are equal to those of the small rails, thus it can sliding freely in the medium rails.  
         [0014]     Said built-in motor is an electric roller, the casing of which is connected with through fixing flange. There is a positioning threaded rod at front side of said rails near the wall or in the rails. There are a pulley and steel ropes at each side of said suspension beam; said steel ropes are used to suspend both ends of said built-in motor. A main shaft control device is mounted in said small rails.  
         [0015]     The invention provides a mini wall polisher comprising two parts: motor part and polishing sandstone cylinder part fixed on the motor and protected with a protection hood; said protection hood has two positioning plates, adjusting grooves, and nuts at the bottom.  
         [0016]     There are dust pipes at said sandstone cylinders; the protrusion length of said dust pipes is equal to the diameter of said sandstone cylinder; said dust pipes run into said motor part and are connected to a hose to an external fan at their rear ends. Said dust pipes are converged to a main pipe at the motor part and the main pipe is connected to the external fan. There are grooves on the inner walls of said dust pipes.  
         [0017]     The technical solution in this invention has the following advantages: 
        (1) It achieves wall polishing automation effectively and decreases labor intensity and improves work efficiency;     (2) It expands the applicability of the machine and may be used to polish inner walls, external walls of rooms of different heights and roofs;     (3) The polisher utilizes the built-in spring in the sliding plate to achieve self-leveling, thus the sandstone cylinder always stick to the wall seamlessly;     The guide sleeve can prevent excessive friction during sliding action and avoid excessive tilting of the support plate during the polishing work.        
 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]      FIG. 1  shows the entire polisher in this invention;  
         [0023]      FIG. 1B  shows the entire polisher in another assembling mode;  
         [0024]      FIG. 1C  shows the entire polisher that utilizes a lifting platform;  
         [0025]      FIG. 2  shows the structure of the guide sleeve in the polisher;  
         [0026]      FIG. 2B  shows the structure of another guide device applicable to the polisher in this invention;  
         [0027]      FIG. 3A  shows the structure of another sandstone disk frame applicable to the polisher in this invention;  
         [0028]      FIG. 4A  shows the structure of the sliding part in  FIG. 3A ;  
         [0029]      FIG. 3B  shows the structure of another sandstone disk frame applicable to the polisher in this invention;  
         [0030]      FIG. 4B  shows the structure of the sliding part in  FIG. 3B ;  
         [0031]      FIG. 3C  shows the structure of another sandstone disk frame applicable to the polisher of this invention.  
         [0032]      FIG. 4C  shows the structure of the sliding part in  FIG. 3C ;  
         [0033]      FIG. 4C   1  shows another structure of the sliding part in  FIG. 3C ;  
         [0034]      FIG. 5A  shows the three-dimensional structure of the sandstone disk frame of the polisher in this invention;  
         [0035]      FIG. 5B  is a structural and installation diagram of the sandstone disk frame of the polisher in this invention for roof polishing work;  
         [0036]      FIG. 6  shows the structure of the sandstone disk protection hood of the polisher in this invention;  
         [0037]      FIG. 6B  shows another structure of the polishing cylinder of the polisher in this invention;  
         [0038]      FIG. 6C  shows another structure of the polishing cylinder of the polisher in this invention;  
         [0039]      FIG. 7A  shows the positions of the pulleys that enable the sliding part and the sandstone disk frame of the polisher to move;  
         [0040]      FIG. 7B  is another view of the positions of the pulleys that enable the sliding part and the sandstone disk frame of the polisher to move;  
         [0041]      FIG. 8  is an assembly drawing of the sliding rails of the polisher as well as a schematic diagram of the position difference correction rail of the polisher in this invention;  
         [0042]      FIG. 9A  shows the structure of the main shaft control device in  FIG. 8 ;  
         [0043]      FIG. 9   b  is another view of the structure of the main shaft control device in  FIG. 8 ;  
         [0044]      FIG. 10  shows the structure of the dust absorption mouth of the polisher in this invention;  
         [0045]      FIG. 11  is a sectional view of the assembly of sandstone disk protection hood and dust absorption mouth of the polisher in this invention;  
         [0046]      FIG. 12  is a circuit control diagram of the motor in this invention;  
         [0047]      FIG. 12B  is a circuit control diagram of the other motor in this invention;  
         [0048]      FIG. 13  is a 3D effect diagram of the mini polisher (without protection hood) in this invention;  
         [0049]      FIG. 14  is a schematic diagram of the mini polisher in this invention;  
         [0050]      FIG. 15  is a 3D effect diagram of the mini polisher in this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0000]     Entire Machine and its Working Principle  
         [0051]     Please see  FIG. 1C , the assembly drawing of the entire machine in this invention. The entire machine in this invention comprises a lifting platform  401  and a polishing unit  402 ; wherein said lifting platform  401  can lift up or drop down the polishing unit  402  to polish a working surface at specific altitude.  
         [0052]     The structure of the lifting platform  401  may be diverse.  FIG. 1C  shows a structure, which comprises a underplate  4011 , rails  4012  fixed on the underplate  4011 , and a motor  4013  fixed on the rails  4012 ; wherein said rails  4012  may be a plurality of rails fitted to each other, and at least one of them is fixed on the underplate  4011 ; the topmost rail is connected to the polishing unit  402 , and the transmission may be screw rod transmission or chain transmission.  
         [0053]     The structure of the polishing unit  402  may be diverse.  FIG. 1C  shows a structure, which comprises a sliding rack  4021  and a polishing cylinder  4022  mounted on the sliding rack  4021 ; said sliding rack  4021  is fixed on the rails  4012  of the lifting platform  401 . Another type of polishing unit  402  (not shown) may be a polishing cylinder that utilizes a built-in motor; said polishing cylinder is directly fitted to the rails  4012 .  
         [0054]     Another assembling method for the wall/roof polisher in this invention is shown in  FIG. 1 ,  FIG. 1B , and  FIG. 5B ; wherein the lifting platform is a fixed part  1 , and the polishing unit is a sliding part  2 ; said fixed part  1  comprises a seat  11 , a top plate  12 , and several upright posts ( 13 ,  13 ′) mounted in parallel between the seat  11  and the top plate  12  (in the embodiment in  FIG. 1 , there are 4 upright posts: 2 front upright posts ( 13 ) are mounted in the middle of the seat  11  at bottom and on front edge of the top plate  12  at top; 2 rear upright posts  13 ′ are mounted on the rear edge of the seat  11  at bottom and on rear edge of the top plate  12  at top; in the embodiment in  FIG. 1B , the 4 upright posts ( 13 ,  13 ′) are mounted in the middle of the seat  11  and the top plate  12 , separately), moving pulleys (not shown) mounted under said seat  11  to adjust the altitude of seat  11  and control the rotation direction in order to enable the fixed part  1  to move in whole; said sliding part  2  comprises an upper support plate  22 , a lower support plate  21 , and two support posts  23  and two sliding rails  24  between the support plates  21  and  22 ; said support posts  23  pass through the top plate  12  of the fixed part  1  (in  FIG. 1 , they pass through between front upright posts  13  and rear upright posts  13 ′; in  FIG. 1B , they pass through behind the four upright posts); in another installation method, an I-beam may be used as the sliding rail  24 , and the front upright posts  13  of the fixed part  1  may be placed in the I-beam, and then the pulleys may be mounted.  
         [0055]     There is a motor  3  mounted on the seat  11  of said fixed part  1 , said motor  3  drives said sliding part  2  to slide along the front upright post  13  of said fixed part  1 ; a sandstone disk frame  25  is fixed on the support plate of said sliding part  2  (during wall polishing work, said sandstone disk frame  25  is fixed on the lower support plate  21 , as shown in  FIG. 1 ; during roof polishing work, said sandstone disk frame  25  is fixed on the upper support plate  22 , as shown in  FIG. 5B ); the sandstone disk  251  in said sandstone disk frame  25  is used to polish wall or roof.  
         [0056]     See  FIG. 7A  and  FIG. 7B , wherein several pulleys are mounted on the polisher in this invention so that the sliding part  2  can be lifted and the sandstone disk frame  25  can slide. There are 5 pulleys on the upper support plate  22  of the sliding part  2 : 2 lifting pulleys  901  at both sides, 2 deflecting pulleys  902  in the middle, and another lifting pulley  903  between the deflecting pulleys  902 ; there are two steel ropes (not shown) suspended at both ends of the sandstone disk frame  25  and they pass through the lifting pulleys  901 , the deflecting pulleys  902 , the lifting pulley  903 , and then run downwards; one or two lifting pulleys  904  are mounted on the lower support plate  21  of the sliding part  2 ; the steel rope running down from the lifting pulley  903  passes through the lifting pulley  904  and then run upwards; there is a lifting pulley  905  and a deflecting pulley  906  below the top plate  12  of the fixed part  1 ; the steel rope passes through the lifting pulley  905  and the deflecting pulley  906  and run downwards into the rope rollers at both ends of the motor  3  on the seat  11 , so that the motor  3  drives the sandstone disk frame  25  to slide in the slide rails  24  and drives the sliding part  2  to slide along the front upright posts  13  of the fixed part  1 .  
         [0057]     In this invention, all components on the upper and lower support plates ( 21 ,  22 ) and the top plate  12  may be mounted separately; however, to simplify the mounting work, the support plate ( 21 ,  22 ), top plate  12 , sleeves and small posts mounted on the rails  24  on those plates, and the hoisting pulleys and the steering pulleys  901 ˜ 904  may be molded on the plates together through fiberglass reinforced plastic molding process.  
         [0000]     Polishing Part  
         [0058]     In this invention, the polishing part  402  accomplishes polishing work with the polishing cylinder. Said polishing cylinder may be a sandstone disk, a sandpaper cylinder, or a metal roller with smooth surface: a sandstone disk may be used to polish coating on worn wall; a sandpaper cylinder may be used to polish new wall to facilitate painting new paint; a metal roller may be used to polish hard coating on wall; in actual application, the polishing cylinder may be selected according to the actual situation of the wall.  
         [0059]     Above polishing cylinder may be mounted in a frame  25  (the structure of it is shown in  FIG. 5A  and  FIG. 5B ); said frame  25  comprises a bottom plate  252 , a sandstone disk  251  fixed on said bottom plate  252 , a sandstone disk protection hood  253  that may turn 90°, and a motor  254  that is fixed on the bottom plate  252  and is used to drive the sandstone disk  251 . The entire sandstone disk frame is fixed on the support plate via the fixing hole (piece)  259  on the bottom plate  252 .  
         [0060]     There are a bearing  255  at each end of the sandstone disk  251 , wherein a pulley  256  is mounted on one bearing  255 , which is connected to the motor  254 . There is a baffle plate  257  at outer side of each bearing  255  and the baffle plate  257  is fixed on the bottom plate  252 .  
         [0061]     Either the sandpaper cylinder or the metal roller may be mounted in the frame  25  in the same way.  
         [0062]     The structure of the sandpaper cylinder is shown in  FIG. 6B . An elastic gum layer  25322  is coated on a bushing  25311 , sandpaper  25333  is fixed to that elastic gum layer  25322  and the bushing  25311 .  
         [0063]     Another structure of the sandpaper cylinder is shown in  FIG. 6C : a disk is fixed at each end of a cylinder; there are several springs  2533 ′ pulled between the disks to form a cylinder; there are several iron rings in the cylinder and they are fixed on the springs; the sandpaper  2533 ′ is fixed on the surface of the cylinder; round rods can be fitted on the springs to fix the springs on the disks  2532 .  
         [0064]     To ensure normal operation of the polishing cylinder during the polishing work, the polishing cylinder is protected with a protection hood  253  (see  FIG. 6 );  4  limiting/positioning pulleys  258  (springs may be added to them) are fixed at the notch of the protection hood  253  to limit the clearance between the polishing cylinder  251  and the working surface. There is a slide channel  2539  at each side of the protection hood  253  so that the protection hood  253  can turn 90° along the slide channels.  
         [0065]     A dust collecting device may be added on the protection hood  253 , as shown in  FIG. 10 .  
         [0066]     A frame  25  is mounted on the upper support plate  21 , as shown in  FIG. 5B ; the protection hood  253  can turn 90°; another fixing part  2591  is mounted on the bottom plate  252  to fix the bottom plate  252  to the corner bracket  221  on the upper support plate  21 .  
         [0067]     A frame  25  is fixed on the lower support plate  21 , as shown in  FIG. 5A ; in addition, a sliding block  250  is mounted at outer side of the bearing baffle plate  257 . The sliding block  250  has 4 small pulleys  2501 , as shown in  FIG. 4A ,  FIG. 4B , and  FIG. 4C ; said sliding block  250  is in the two slide rails  24  of the sliding part  2  and can slide in them.  
         [0068]     The structure of the sliding block  250  may be diverse. As shown in  FIG. 4A , there is a naked shaft  2502  vertical to the sliding direction (Direction A) at each end of the sliding block  250 ; said naked shafts  2502  are mounted between the baffle plate  2503  of the sliding block and are fitted with a spring  2504  respectively; said naked shafts  2502  are detachable; in the sandstone disk frame  25  (see  FIG. 3A ) corresponding to the naked shaft structure, two linear bearings  2571  are fixed at top/bottom of the bearing baffle plate  257 , respectively; the naked shafts  2502  of said sliding block  250  pass through said linear bearings  2571  respectively, and said springs  2504  prop the fixing frames of said linear bearings  2571 , respectively.  
         [0069]      FIG. 4B  shows another structure of said sliding block  250 , wherein the small pulleys  2501  of said sliding block  250  are connected to a naked shaft  2502 ′ respectively; said naked shafts  2502  are fitted with a spring  250  respectively, and the other end of each naked shaft  2502  is fixed at the other side of said sliding block  250  in a detachable manner (e.g., fixed with nuts (not shown)) so that it can stretch freely. The sliding block  250  of that structure is fixed to the bearing baffle plates  257  of the sandstone disk frame  25  through the fixing holes  2505 , as shown in  FIG. 3B .  
         [0070]      FIG. 4C  shows another structure of the sliding block  250 , wherein there are 4 eccentric pulleys  2501  (may be substituted with common grooved pulleys, as  2501 ′ shown in  FIG. 4C   1 ) on the sliding block  250 ; there is a naked shaft  2502  vertical to the sliding direction (Direction A) at each end of said sliding block  250 ; said naked shafts  2502  are mounted between the baffle plates  2503  of the sliding block and are fitted with a spring  2504  respectively; said naked shafts  2502  pass through a small slab fixed to the bearing baffle plate  257  at one end and are fixed to the baffle plate  2503  of the sliding block in a detachable manner at the other end; a set of pulleys  2506  are fixed on the sliding block  250  to reduce friction between the baffle plate  2503  of the sliding block and the bearing baffle plates  257 ; there are another 2 sets of pulleys  2507  on the sliding block  250 , and another baffle plate (not shown) may be inserted into the gap between the 2 sets of pulleys  2507  and fixed to the baffle plate  2503  to drive the sliding block  250  to slide up and down; the difference between  FIG. 4C   1  and  FIG. 4C  is: there is only one spring  2504  in  FIG. 4C   1 , and the eccentric pulley  2501  in  FIG. 4C  is substituted with a common grooved pulley  2510  in  FIG. 4C   1 .  
         [0071]     The spring  2504  in any of above structures of the sliding block  250  may create counter force under the pushing force of the operator during the polishing work, so that the sandstone cylinder always stick to uneven wall face. The polishing accuracy may be adjusted through adjusting the contracting range of the spring  2504 .  
         [0072]     In this invention, all of the components mounted on the bearing baffle plates  257  may be mounted separately or molded together during the bearing baffle plates  257  are molded.  
         [0000]     Guiding Device  
         [0073]     Please see  FIG. 1 , wherein two guide sleeves  26  are mounted on the lower support plate  21  of said sliding part  2 , corresponding to the two front upright posts  13  of the fixing part  1 ; whereas two identical guide sleeves  26  are mounted on the bottom of top plate  12  of the fixing part  1 , corresponding to the two support posts  23  of the sliding part  2 . The structure of the guide sleeves  26  is shown in  FIG. 2 ; the two pulleys  261  of said guide sleeves  26  will prop the side faces of said upright posts  13  and support posts  23  and roll along said side faces when the sliding part  2  slides along the fixing part  1 . The action of guide sleeves  26  can reduce friction between the top plate  12  and the upright posts  13  and tilt of the sliding part  2 , and prevent the upright posts  13  from bearing excessive pressure through the limiting action of the holes.  
         [0074]      FIG. 2B  shows another guiding device, which is a spring device mounted directly on the support plate  21  and the top plate  12 .  
         [0000]     Slide Rail and Main Shaft Control Device  
         [0075]     The following issues are considered in the design of this invention:  
         [0076]     (1) Presently, rails in mechanical equipment usually employ U-steel cross section; however, rails of U-steel cross section will increase shock and degrade accuracy in this invention. Therefore, “□” shape cross section is used in this invention, and the corners are designed in circular arc shape or even circular shape.  
         [0077]     (2) The lower the gravity center is, the higher the stability is. The “Synthetic Resin and Plastics—Synthetic Fiber” issued by Chemical Industry Press describes: “unsaturated polyester fiberglass reinforced plastics is excellent in mechanical properties. Fiberglass reinforced plastics reinforced with non-alkali glass cloth or fiber glass is similar to steel in some properties but the density of it is only ¼˜⅕ of Fe or ½ of Al; it is easy to shape and possesses superior chemical properties. This invention employs unsaturated polyester fiberglass reinforced plastics for the frame and slide rails  24  to reduce the weight of the upper portion; so that the gravity center of the machine is lowered and the stability is enhanced. In addition, it also facilities installation and handling of the equipment; in view that resin plastic products are easy to distort and low in wear-ability, sheet iron, tin foil, or other wear resistant materials may be used to protect the slide rails; both the top plate and the bottom plate can be made of fiberglass reinforced plastics.  
         [0078]     (3) When the wall polisher is used to polish inner walls, small rails of 1.5 m length can be fitted into big rails of 2.5 m length to meet the altitude requirement in view that the inner walls usually don&#39;t exceed 4 m in height. The shorter the rails are, the higher the stability is.  
         [0079]     The slide rails  24  on the sliding part  2  are assembled through fitting bigger rails over smaller ones, as shown in  FIG. 8 ; the dimensions of external walls of smaller rails are almost the same as those of inner walls of bigger rails. There are fixing holes  243  on rails  241  and  242 . Therefore, the rails  241  and  242  may be fixed to each other at the fixing holes  243 .  
         [0080]     As shown in  FIG. 8 , smaller rails  241  are mounted in bigger rails  242 , and the main shaft control device  244  and the position difference correction rail  245  are mounted in those rails; when the main shaft control device  244  moves in the bigger rails  242 , the position difference correction rail  245  will move along with the main shaft control device  244  under magnetic force; when the main shaft control device  244  moves upwards and enters into the smaller rails  241 , the top of the position difference correction rail  245  will touch the bottom of the smaller rails  241  and will be linked to the smaller rails  241  under magnetic force; when the main shaft control device  244  moves downwards, the case is reverse; the main shaft control device  244  and the position difference correction rail  245  are equipped with a magnetic material.  
         [0081]     In this invention, if the motor  254  that drives the sandstone disk  251  is a built-in one, the main shaft of the motor will serve as the stator and should not rotate. To attain this purpose, a main shaft control device  244  should be added.  
         [0082]      FIG. 9A  shows above main shaft control device  244 , which comprises small bearings  2442 , vertical shaft  2443 , small spring  2444 , screw  2445 , and main shaft hole  2446 ; the small bearings  2442  are mounted on a vertical shaft  2443 , and the main shaft control device  244  is adjusted with screw  2445  and spring  2444  to adapt to the rail  241 .  
         [0083]     The main shaft control device  244  may also employ any other structure.  FIG. 9B  shows an adjustable main shaft control device  244 ′. Different to  FIG. 9A , the sides of the main shaft control device  244 ′ are smooth iron sheets  2447 , which are adjustable to adapt to the rails.  
         [0084]     In this invention, the main shaft control device  244  is designed as a sliding block, the outer diameter of which is identical to the inner diameter of the small rails  241 ; thus the main shaft control device  244  can slide in the small rails  241  and keep the main shaft of the motor  245  stationary.  
         [0000]     Dust Absorption and Safety Protection  
         [0085]     A great deal of dust will occur when you polish wall with the polisher. A large part of the dust flies in the original direction and then spread quickly under air resistance; some of the dust clings to sandstone disk  251  and flies out along with the rotation of the sandstone disk  251 , and then hits the polishing surface and flies about; some of the dust will stick to the polished wall face and should be cleared, otherwise it will degrade the viscous force of the paint and result in peeling-off.  
         [0086]     In view of above issue, the protection hood  253  is accompanied with a dust collecting device, i.e., a dust absorption mouth  2534  is mounted on the protection hood  253 , as shown in  FIG. 10 ; said dust absorption mouth  2534  comprises an air inlet  2531 , a chamber  2532 , and hose outlets  2533 ; said dust absorption mouth is a flat mouth, and it length is equal to the length of the sandstone disk  251 ; the chamber  2532  is relatively larger and may be connected to several flat mouths simultaneously. The dust created during polishing work enters into the chamber  2532  via the air inlet  2531  and rotate in the chamber  2532 ; under the wind power at both sides in the chamber, the dust is driven into the hoses at both sides via the hose outlets  2533 , and then enter into the dust bag of the dust collecting device.  
         [0087]     The following factors shall be taken into consideration when the dust absorption mouth  2534  is mounted: first, the dust absorption mouth shall be near the position where the dust is created. (under the sandstone cylinder) as much as possible; second, the dust absorption direction shall be in the dust flying path; third, the area of the dust inlet under the sandstone cylinder should be small so that air flow can occur there to suck in the dust, the space above the sandstone cylinder should be big enough and covered with a wind shield to reduce flying speed of dust and facilitate dust absorption. The three important dust absorption positions are (in order): under the sandstone disk, dust flying point above the sandstone disk; above the sandstone disk.  
         [0088]     According to the actual situation of dust out-fly, the sandstone disk protection hood  253  is designed as a safety protection hood that can collect dust in several grades, as shown in  FIG. 11 . In detail, the bottom of the safety protection hood  253  is a baffle plate  37  that may be adjusted with  38 ; a soft gum annular dust pipe  300  is fixed in the baffle plate  37  and it is connected to the air intake mouth  2531  through a communication pipe  36 ; the baffle plate  37  may be adjusted so that the annular dust pipe  300  is near the polish surface as much as possible to reduce the distance between the sandstone cylinder and the working surface, in order to form strong air flow to suck in dust; the baffle plate  37  may be adjusted as required so that sand will drop onto the ground but dust will enter into the safety protection hood; a small brush  39  may be mounted on the baffle plate of the safety protection hood to brush off dust sticking to the wall; when dust falls off, lighter dust is taken into the safety protection hood, but heavier dust fall onto the ground; in addition, another mouth  2531  may be mounted on top of the safety protection hood and it is connected to the air intake mouth  2534 ; said mouth  2531  may suck in dust flying from the sandstone disk; furthermore, the mouth  2531  may be near the sandstone cylinder as much as possible to take dust in the sandstone disk; a baffle plate  301  may be mounted in the safety protection hood to reduce flying speed of dust and enhance the dust absorption effect at the air intake mouth  2531 . Dust sucked into above 3 air intake mouths  2531  will enter into a chamber and then into the hoses  300 . To enhance dust absorption effect, the safety protection hood may be wrapped with a gum cover to increase air tightness.  
         [0089]     See  FIG. 1C , wherein an air outlet may be mounted at rear-end of the protection hood  253  (according to air tunnel principle, a small motor may also be added to enhance dust absorption effect); said air outlet is connected to a flexible rubber hose, which is connected to the dust collector  405 .  
         [0090]     See  FIG. 6 , wherein there are small positioning pulleys  258  fixed on the protection hood  253  and bearings mounted on both sides of the protection hood  253 ; said bearings are fitted on the shafts so that the safety protection hood can turn along the uneven wall face and the positioning effect of the positioning pulleys are maximized.  
         [0000]     Positioning/Limiting Device  
         [0091]     In this invention, the clearance between the sandstone disk and the polishing surface may be limited with the small pulleys mounted on the protection hood  253  or the bearing baffle plate  257 . The polishing depth of the sandstone disk  251  may be adjusted to attain positioned polishing effect; in addition, the positioning area is relatively small through that positioning method, thus both the workload and work difficulty will be reduced.  
         [0092]     The clearance between the fixing part  1  and the polish surface may be limited through mounting  2  positioning/limiting rods  19  (see  FIG. 1 ) at the edge of top plate  12  of the fixing plate  1  or top of front upright post  13 . Such a positioning method is ideal for positioning larger area.  
         [0093]     In case the gradient of the polishing surface is high, positioning threaded rods  28  may be mounted on top of slide rails  24  (see  FIG. 1 ); the polishing accuracy may be adjusted through adjusting the positioning threaded rods; though that method is ideal for positioned polishing, the workload is huge.  
         [0094]     Above positioning/limiting methods may be used in combination to achieve self-leveling function of the polisher.  
         [0000]     Circuit Control Part  
         [0095]     To simplify the operation, a travel switch may be used when the travel switch is triggered, the lifting motor will rotate and the polisher will rise up; when the polisher reaches to the top of the wall, the lifting motor will rotate in the reversed direction, thus the polisher will go down; when the polisher reaches to the bottom, the lifting motor will stop; when the motor is started again, the polisher will rise up again; in case a certain position on the wall face is to be repaired, the polisher may be moved to that position manually; the operation part may utilize safety voltage.  FIG. 12  and  FIG. 12B  show the circuit control diagram.  
         [0096]     Instruction to the symbols in  FIG. 12B :  
                                           1SB   Master stop button   LA1       2SB   Polishing head rising control button   LA1       3SB   Polishing head dropping control button   LA1       4SB   “Dust collector on” button   LA1       5SB   “Dust collector off” button   LA1       6SB   “polishing head on” button   LA1       7SB   “polishing head off” button   LA1       1QA, 2QA   Top travel switch   JLXK1       3QA   Bottom travel switch   JLXK1       KM1, KM4   AC contactor   CJX2-123                (with auxiliary               contact)       KM2, KM3   AC contactor   CJ10-5 or               CJ20-10       M1   Climbing control motor   YcJT-90-1/4               (with decelerator)       M2   Motor of dust collector       M3   Motor of polishing head                  
 
         [0097]     The circuit can control the polishing head to ascend and descend as well as ascending/descending switching action with the travel switch; it can control the polishing head and the dust collector to start/stop.  
         [0098]     Implementation:  
         [0099]     (1) Under normal condition (power on), when the “6SB” button is pressed down, the polishing head will start working; when the “2SB” button is pressed down, the polishing head will climb up under the drive of the lifting motor.  
         [0100]     (2) When the entire support rises to the top position or the top of the support touches the ceiling, under the action of 1QA and 2QA, the lifting motor rotates in reverse direction, thus the polishing head will descend.  
         [0101]     (3) When the polishing head reaches to the bottom, the lifting motor will stop under the action of 3QA. Then the polishing head stops at the bottom position.  
         [0102]     (4) When the “5SB” button is pressed down, the dust collector will be started to absorb dust created during polishing work.  
         [0103]     (5) When the “1SB” button is pressed down, the machine will stop.  
         [0104]     (6) When “2SB” or “3SB” is pressed down during the polishing head moves, the moving direction of the polishing head will be reversed to meet special requirements during the polishing work.  
         [0105]     (7) “5SB” and “7SB” control the polishing head and the dust collector independently. In case the dust is not severe, the dust collector may be stopped.  
         [0106]     (8) The entire circuit is installed in a electric control cabinet and the machine is controlled with a contactor; thus it can ensure personnel safety and prevent electric shock effectively.  
         [0000]     Mini Polisher  
         [0107]     Above polisher in this invention is relatively huge and inconvenient to polish wall corners. For this reason, this invention provides another handheld mini polisher, as shown in  FIG. 13 ˜ 15 ; said mini polisher comprises 2 parts: polishing sandstone cylinder  100 , and motor  101  and safety protection hood  107 ; said safety protection hood  107  has a positioning surface  109  at the bottom, adjusting channels  110 , and nuts  111 ; the sandstone cylinder  100  is protected with the safety protection hood  107  and is fixed on the motor  101 ; there is a hole under the safety protection hood  107 ; the sandstone cylinder may protrude a little through adjusting the channels  110  and nuts  111 ; there are 2 positioning surfaces  109  at sides under the sandstone cylinder; the machine can detect a plane to proceed polishing work with those positioning surfaces  109 ; the safety protection hood  107  also wraps the motor  101  to form a handheld polishing bar; the surfaces  109  under the safety protection hood  107  achieve positioning effect; through adjusting the safety protection hood  107  with the channels  110  and the nuts  111 , the sandstone cylinder  100  may protrude a little to polish walls, so that the polishing depth may be adjusted.  
         [0108]     The dust absorption part of the mini polisher is designed as follows: a small iron tube is fixed on the motor  101  and comprises two portions: the portion extruding from the sandstone cylinder  100  is called “dust pipe”  102 , and the portion fixed onto the motor is called “air feeder”  103 ; there is an air flow control switch at the back end of the air feeder  103 ; the air feeders are combined into an air outlet  105 , which is connected to a hose, a force fan, and the bag of the force fan to achieve dust collection; the dust pipe  102  is outside of the safety protection hood; there is a groove  106  (or a hole) in the safety protection hood (dust pipe  102 ) to facilitate dust and sand to enter into the dust pipe  102 .  
         [0109]     The mini polisher is small and can be held by hand; it is ideal for wall corner polishing work.  
       Industrial Applicability  
       [0110]     This invention has the following benefits:  
         [0111]     1. Due to the utilization of rail assembly and the position difference correction rail, the polisher in this invention is applicable to different rooms and external walls; due to the design of cross section of the rails and the application of the slide plates, equipment shock is reduced significantly and the stability is enhanced.  
         [0112]     2. The guide sleeve can prevent excessive friction during sliding action and avoid excessive tilting of the support plate during the polishing work.  
         [0113]     3. The polisher in this invention achieves self-leveling function with the built-in spring in the sliding block.  
         [0114]     4. High dust absorption efficiency grants application feasibility of the machine.  
         [0115]     5. Combined utilization of the threaded rod positioning system and the pulley positioning system on sandstone disk protection hood increase the application value of the machine.  
         [0116]     6. The handheld mini polisher is a complement to the big machine.  
         [0117]     In view of above benefits, the wall polisher in this invention can be used widely in wall polishing work and has high industrial applicability.

Summary:
This invention discloses a large-scale wall polisher that is operated by a single operator and applicable to polish different rooms, external walls, and ceilings and with dust absorption and positioning functions; in addition, as a complement to the large-scale machine, this invention also provides a handheld mini wall polisher that has dust absorption and positioning functions. This invention is convenient and practical, and is applicable to chisel worn walls and polish new walls; It achieves polishing automation reduces labor intensity, and enhances work efficiency; moreover, it can also enhance the esthetic appearance of polished walls.