Abstract:
The invention relates to the field of machinery, and in particular relates to a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads, which is applicable to the digging field or the field of engineering machinery. The apparatus comprises an impact power box and impact heads, wherein the impact heads are arranged at one end or two ends of the impact power box, more than two impact heads are arranged at each end of the impact power box, and the more than two impact heads are arranged vertically and/or bilaterally to increase the digging height and/or digging width. The apparatus is reliable in performance, strong in manufacturability, simple to machine and manufacture and long in service life.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of machinery, and in particular relates to a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads, which is applicable to the digging field or the field of engineering machinery. 
       BACKGROUND OF THE INVENTION 
       [0002]    At present, most of the coal mining machines and heading machines adopt drum-type rotary milling blanking, and most of the excavators dig and break materials with single buckets or single-tooth impact heads. With the development of technology, reciprocating impact type coal mining machines, reciprocating impact type heading machines and reciprocating impact type excavators are invented, which are collectively named as reciprocating impact digging machines. The impact heads of the reciprocating impact digging machines have the advantages of high lump material digging rate, less dust and low energy consumption, but the digging height and/or width of the impact heads may not meet the requirement for digging thick coal seams, high coal seams, thick rock strata, high rock strata, thick cement concrete, wide cement concrete, thick asphalt concrete, wide asphalt concrete, thick hardened mudstones or wide hardened mudstones, and to meet this requirement, the present invention provides a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention is realized through the following technical scheme: a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads includes an impact power device and impact heads, and is characterized in that the impact heads are arranged at one end or two ends of the impact power device, more than two impact heads are arranged at each end of the impact power device, and the more than two impact heads are arranged vertically and/or bilaterally, so as to increase the digging height and/or digging width. 
         [0004]    The small-resistance and high-efficiency digging apparatus with multiple layers of impact heads includes an impact power device, wherein the impact power device includes an impact power box or an impact power support; the impact power box includes an impact mechanism, a guide mechanism and a box body; the impact mechanism is a hydraulic impact mechanism or a pneumatic impact mechanism or an electric impact mechanism; the electric impact mechanism includes a central shaft, a driving gear, a transmission gear, a crankshaft and a connecting rod; the connecting rod includes a power impact member, the connecting rod is separately connected with or integrated with the power impact member, the box body supports the central shaft, and the driving gear is arranged on the central shaft or integrated with the central shaft; the box body supports the crankshaft, the transmission gear is arranged on the crankshaft and separately connected with or integrated with the crankshaft, the driving gear is engaged with the transmission gear, one end of the connecting rod is connected with the crankshaft, and the other end of the connecting rod is connected with an impact head; the box body supports the guide mechanism which includes an impact guide member, impact heads are arranged at one end or two ends of the impact guide member, and the impact guide member is separated from or separately connected or integrated with the impact heads; and the central shaft drives the driving gear to rotate, the driving gear drives the transmission gear to rotate, the transmission gear drives the crankshaft to rotate, the crankshaft drives the connecting rod to reciprocate, the connecting rod drives the impact heads to reciprocate, and the impact heads are guided by the impact guide member to reciprocate. The impact guide member is separated from or separately connected or integrated with the power impact member. 
         [0005]    The impact power device includes a box body, plug hammers and a control valve, wherein the box body includes more than two cavities, more than two plug hammers are arranged in the more than two cavities, the control valve controls liquid or gas, the liquid or the gas drives the more than two plug hammers to reciprocate, the more than two plug hammers drive more than two impact heads to reciprocate, and the more than two cavities are arranged vertically and/or bilaterally to increase the digging height or width. 
         [0006]    Each plug hammer includes a plug rod, and damage-proof power impact member mechanisms are arranged at one end or two ends of the plug rod. 
         [0007]    The driving gear drives more than one transmission gear. 
         [0008]    The crankshaft and/or the central shaft include two or more eccentric shafts. 
         [0009]    The driving gear drives the transmission gears to rotate, each transmission gear drives the crankshaft to rotate, and more than one eccentric shaft is at least arranged on the crankshaft. 
         [0010]    The more than one crankshaft is arranged symmetrically or asymmetrically relative to the central shaft. 
         [0011]    More than one eccentric shaft is arranged on the central shaft, and the eccentric shaft is hinged with a connecting rod. 
         [0012]    The eccentric shaft is arranged on more than one side of the transmission gear and/or the driving gear. 
         [0013]    The impact power device includes a guide mechanism, the guide mechanism is a suspended friction guide mechanism or a rolling friction guide mechanism or a sliding friction guide mechanism, and the guide mechanism includes impact guide members, a guide supporting member and a guide body, wherein the guide supporting member is separated from or separately connected or integrated with the box body, and the guide body is arranged between the guide supporting member and the impact guide members. 
         [0014]    Two impact heads move in a front-and-back staggered manner. 
         [0015]    The impact guide members which are adjacent to the two impact heads and move in a front-and-back staggered manner share one guide body to save space. 
         [0016]    A connecting rod drives one or more impact heads. 
         [0017]    Damage-proof power impact member mechanisms are arranged at one end or two ends of the connecting rod, each damage-proof power impact member mechanism includes a rotary or split or buffering damage-proof power impact member mechanism, the counterforce produced when the impact heads impact a material layer is applied to the damage-proof power impact member mechanism, and the rotary damage-proof power impact member mechanism rotates to decompose the impact counterforce or the split damage-proof power impact member mechanism is split to isolate the impact counterforce or the buffering damage-proof power impact member mechanism absorbs and decomposes the impact counterforce by buffering, so as to prevent the impact counterforce from damaging the impact power device. 
         [0018]    The rotary damage-proof power impact member mechanism is a joint bearing or a steering connector or a ball cage type universal joint or a cross universal joint or a bulb catching groove type universal joint or an arc-shaped catching groove type universal joint. 
         [0019]    The guide body is a suspended guide body or a rolling guide body. 
         [0020]    The rolling guide body is a spherical, elliptical, dumbbell-shaped, cylindrical, conical, circular, roller type, table column type, table ball type, table drum type, groove-shaped drum type, groove-shaped column type, groove-shaped ball type, groove-shaped roller type, groove-shaped elliptical, shaft-carrying, perforated, multi-edge key type, multi-edge sleeve type, rolling drum type, ball type, rolling needle type, drum type, linear bearing type, waist drum wheel type or combined rolling guide body. 
         [0021]    The suspended guide body is a suspended liquid guide body or a suspended gas guide body or a suspended magnetic guide body. 
         [0022]    The plurality of impact heads alternately impact a material, so as to reduce the damage of the counterforce produced by simultaneous impact of the plurality of impact heads to the impact power device. 
         [0023]    A lubricating liquid passage is formed in the central shaft and/or the crankshaft and/or the connecting rod. 
         [0024]    Each impact head includes impact teeth and a rack. 
         [0025]    The impact teeth are arranged in a step shape on the rack to form a step-type or conical impact head, so as to impact the material layer into a step shape and break the structural strength of a material layer; the step-type impact head continuously impacts the step-shaped material layer, so as to reduce the impact resistance and increase the digging depth; and the step-shaped material layer is dug to lump granularity suitable for transport and use during the next impact. 
         [0026]    A water spray mechanism and/or a mist spray mechanism are arranged on the rack. 
         [0027]    The impact teeth include surface cleaning teeth and/or blanking teeth, wherein the surface cleaning teeth clean the material layer into a required shape, so as to facilitate supporting and passing of the machine body. 
         [0028]    The small-resistance and high-efficiency digging apparatus with multiple layers of impact heads includes a machine body and a traveling part, wherein the impact power device is arranged on the machine body, the traveling part drives the machine body to travel, and the machine body drives the impact power device to travel. 
         [0029]    The small-resistance and high-efficiency digging apparatus with multiple layers of impact heads includes a lifting mechanism which includes a vertical lifting mechanism or a rocker arm or a translation lifting mechanism. 
         [0030]    The small-resistance and high-efficiency digging apparatus with multiple layers of impact heads includes a rocker arm, wherein one end of the rocker arm is arranged on the machine body, and the other end of the rocker arm is connected with the impact power device. 
         [0031]    The machine body or the traveling part includes a rotary disk which is arranged at the front end of the upper part of the machine body or the upper part of the traveling part at the lower part of the machine body. 
         [0032]    The vertical lifting mechanism or the rocker arm or the impact power device is arranged on the rotary disk, the rotary disk rotates to drive the vertical lifting mechanism or the rocker arm to rotate, and the vertical lifting mechanism or the rocker arm drives the impact power device to rotate. 
         [0033]    The vertical lifting mechanism or the rocker arm or the impact power device is arranged on the machine body, the rotary disk drives the machine body to rotate, and the machine body drives the impact power device to rotate. 
         [0034]    The rocker arm includes a four-link rocker arm mechanism or a single rocker arm mechanism. The single rocker arm mechanism is a rotary, telescopic, telescopic rotary or bent single rocker arm mechanism. 
         [0035]    Each impact head is supported and guided by one or more impact guide members to form a multi-point supporting structure so as to centralize the impact direction of the impact head. Each impact head includes an outer-layer material impact mechanism and an inner-layer material impact mechanism, the outer-layer material impact mechanism is arranged close to the inner-layer material impact mechanism, the outer-layer material impact mechanism includes outer-material impacting teeth, the inner-layer material impact mechanism includes inner-material impacting teeth, the shape and/or arrangement of the outer-material impacting teeth are favorable for impacting the outer material of a material layer to be dug, gaps between the outer-material impacting teeth are favorable for the flowing of the material fallen because of impaction of the inner-layer material impact mechanism thereto or the outer-layer material impact mechanism is provided with a discharging hole for discharging the material fallen because of impaction of the inner-layer material impact mechanism, and the inner-layer material impact mechanism is matched with the outer-layer material impact mechanism to realize impact blanking and discharging, so that the continuously dug material may smoothly pass through the machine body. 
         [0036]    The outer-layer material impact mechanism includes outer-material impacting teeth, an outer-material impacting tooth holder and an outer-material impacting protective member, wherein the outer-material impacting tooth holder is separately connected or integrated with the outer-material impacting teeth; the inner-layer material impact mechanism includes inner-material impacting teeth, an inner-material impacting tooth holder and an inner-material impacting protective member, wherein the inner-material impacting tooth holder is separately connected or integrated with the inner-material impacting teeth; the outer-material impacting protective member is separately connected or integrated with the outer-material impacting tooth holder, and the inner-material impacting protective member is separately connected or integrated with the inner-material impacting tooth holder; the impact power box drives the outer-layer material impact mechanism and the inner-layer material impact mechanism to reciprocate; and the outer-material impacting protective member and the impact power box as well as the inner-material impacting protective member and the impact power box are partially superposed all the time, so as to prevent the material from entering the outer-material impacting protective member and the impact power box and/or prevent the material from entering the inner-material impacting protective member and the impact power box. 
         [0037]    The outer-material impacting protective member includes an outer-material impacting protective plate which is arranged around the outer-material impacting tooth holder, and the inner-material impacting protective member includes an inner-material impacting protective plate which is arranged around the inner-material impacting tooth holder. 
         [0038]    The inner-material impacting protective member reciprocates along with the inner-material impacting tooth holder, the outer-material impacting protective member reciprocates along with the outer-material impacting tooth holder, the inner-material impacting protective plate and the outer-material impacting protective plate are attached to the impact power box to reciprocate, and each attached part is provided with an anti-wear gap. 
         [0039]    The inner-material impacting protective plate includes an inner-material impacting protective plate sealing member, the outer-material impacting protective plate includes an outer-material impacting protective plate sealing member, the inner-material impacting protective plate sealing member and/or the outer-material impacting protective plate sealing member are arranged at the ends superposed with the impact power box all the time, and the impact power box includes an impact power box sealing member which is arranged at the end superposed with the inner-material impacting protective plate and the outer-material impacting protective plate all the time. 
         [0040]    A sealing member is arranged at the joint part of the inner-material impacting protective plate and the inner-material impacting tooth holder, and a sealing member is arranged at the joint part of the outer-material impacting protective plate and the outer-material impacting tooth holder. 
         [0041]    The impact power box includes a protective plate travel groove, the outer-material impacting protective member includes an outer-material impacting protective plate, the inner-material impacting protective member includes an inner-material impacting protective plate, and the adjacent parts of the inner-material impacting protective plate and the outer-material impacting protective plate reciprocate in the protective plate travel groove. 
         [0042]    An elastomer is arranged in the protective plate travel groove. 
         [0043]    An elastomer is arranged at the free end of the outer-material impacting protective plate and/or an elastomer is arranged at the free end of the inner-material impacting protective plate. 
         [0044]    The elastomer shakes off and ejects the material brought by the outer-material impacting protective plate and/or the inner-material impacting protective plate and/or the material falling into the protective plate travel groove through elastic deformation. 
         [0045]    The elastomer absorbs the impact counterforce of the outer-layer material impact mechanism and/or the inner-layer material impact mechanism through elastic deformation. 
         [0046]    The present invention has the following beneficial effects: 
         [0000]    (1) according to the small-resistance and high-efficiency digging apparatus with multiple layers of impact heads, the impact heads are arranged at one end or two ends of the impact power device, more than two impact heads are arranged at each end of the impact power device, and the more than two impact heads are arranged vertically and/or bilaterally, so as to increase the digging height and/or digging width;
 
(2) according to the small-resistance and high-efficiency digging apparatus with multiple layers of impact heads, the driving gear drives the transmission gears to rotate, and the transmission gears drive the crankshaft to rotate, thus a plurality of impact heads are added for impact blanking, and the defects that an impact head bears over-high impact resistance, is low in efficiency and the like because the impact head is made to be over high and over wide in order to increase the digging height when a crankshaft drives a layer of impact heads to impact are overcome;
 
(3) the driving gear drives more than two transmission gears to rotate, so that an impact structure of multiple layers of vertical and/or bilateral impact heads may be formed, and the plurality of impact heads increase the digging height and the digging width; when each impact head carries out impacting, as the width and height of the impact head are moderate and reasonable, the impact resistance is greatly reduced, and break-off of single impact shovels on the impact counterforce of the impact power box is reduced; a plurality of impact shovels alternately carry out impacting, so that the impact power is utilized reasonably, and the efficiency is high;
 
(4) the gears are movably connected with each other, so that certain break-off resistance and buffering effect are achieved;
 
(5) more than one crankshaft is arranged symmetrically relative to the central shaft, so that the structure is stable, and the stress is balanced;
 
(6) more than one eccentric shaft is arranged on the central shaft, and the central shaft drives more than one impact head to carry out impacting, so that the central shaft has a transmission function and an impact blanking function, the space utilization rate is high and the structure is compact;
 
(7) the eccentric shafts are arranged on the two sides of the transmission gear and/or the driving wheel and are supported by the box body or the bracket, so that the structure is reasonable and stable;
 
(8) the plurality of impact heads move in the front-and-back staggered manner, so that the power is concentrated on an impact head, the instantaneous impact bursting force is large and the impact strength is high; the plurality of impact heads alternately carry out impacting, so that the digging height is large, the amplitude is wide and the efficiency is high;
 
(9) two adjacent impact heads move in the front-and-back staggered manner, and the impact guide members of the impact heads share one guide body, so that the space and components are saved;
 
(10) more than two eccentric shafts are arranged on the side of each gear, so that the digging height and/or width are further increased;
 
(11) the damage-proof power impact member mechanism is arranged between each connecting rod and each impact head, the counterforce produced when the impact head impacts the material layer is applied to the damage-proof power impact member mechanism, the rotary damage-proof power impact member mechanism rotates to decompose the impact counterforce or the split damage-proof power impact member mechanism is split to isolate the impact counterforce or the buffering damage-proof power impact member mechanism absorbs and decomposes the impact counterforce by buffering, so as to prevent the impact counterforce from damaging the impact power device;
 
(12) the rolling guide body and/or the suspended guide body greatly reduce the reciprocating impact friction resistance, reduce the noise and improve the efficiency;
 
(13) through the lubricating liquid passages arranged in the central shaft and/or the crankshaft and/or the connecting rod, the lubricating and cooling effect on the central shaft, the crankshaft and the connecting rod is improved, and the operating reliability of the system is ensured;
 
(14) the water spray mechanism or the mist spray mechanism arranged on the rack reduces sparks and achieves a good cooling effect on the impact teeth;
 
(15) the surface cleaning teeth and/or the blanking teeth are used together, so that blanking and surface cleaning are realized, smooth passing of the machine body is ensured, and the blanking efficiency is improved;
 
(16) the rotary disk is arranged at the front end of the upper part of the machine body, the vertical lifting mechanism or the rocker arm is arranged on the rotary disk, the rotary disk rotates to drive the rocker arm to rotate, and the rocker arm drives the impact power device to rotate, so that multi-directional impact blanking and digging are realized;
 
(17) the rotary disk is arranged at the upper part of the traveling part at the lower part of the machine body, the vertical lifting mechanism or the rocker arm or the power impact device is arranged on the machine body, the rotary disk drives the machine body to rotate, and the machine body drives the impact power device to rotate, so that multi-directional impact blanking and digging are realized;
 
(18) the four-link rocker arm mechanism ensures that the impact guide members are parallel to the machine body all the time, and ensures that the impact heads are vertical to the impact material layer;
 
(19) the rotary, telescopic, telescopic rotary or bent single rocker arm mechanism increases the impact digging flexibility of the impact heads, and increases the impact digging width and/or height of the impact heads;
 
(20) each impact head is supported and guided by more than two impact guide members to form a multi-point supporting structure, so as to centralize the impact direction of the impact head and reduce the pressure and damage when the single impact guide member supports the impact head;
 
(21) the shape and/or arrangement of the outer-material impacting teeth are favorable for impacting the outer material of the material layer to be dug, the gaps between the outer-material impacting teeth are favorable for the flowing of the material fallen because of impaction of the inner-layer material impact mechanism thereto or the outer-layer material impact mechanism is provided with the discharging hole for discharging the material fallen because of impaction of the inner-layer material impact mechanism, and the inner-layer material impact mechanism is matched with the outer-layer material impact mechanism to realize impact blanking and discharging, so that the continuously dug material may smoothly pass through the machine body;
 
(22) the impact power box drives the outer-layer material impact mechanism and the inner-layer material impact mechanism to reciprocate, and the outer-material impacting protective member and the impact power box as well as the inner-material impacting protective member and the impact power box are partially superposed all the time, so as to prevent the material from entering the outer-material impacting protective member and the impact power box and/or prevent the material from entering the inner-material impacting protective member and the impact power box, prevent the obstruction to the impact travel because the material enters the space between the impact power box and the outer-layer material impact mechanism and/or between the impact power box and the inner-layer material impact mechanism, and improve the cleanliness of working components of the impact power device;
 
(23) the inner-material impacting protective plate sealing member and/or the outer-material impacting protective plate sealing member are arranged at the ends superposed with the impact power box all the time, and the impact power box sealing member is arranged at the end superposed with the inner-material impacting protective plate and the outer-material impacting protective plate all the time, so that the cleanliness of the working components of the impact power device is further improved, and the operating safety and reliability of the apparatus are ensured;
 
(24) the elastomer is arranged in the protective plate travel groove, the elastomer is arranged at the free end of the outer-material impacting protective plate and/or the free end of the inner-material impacting protective plate, the elastomer shakes off and ejects the material brought by the outer-material impacting protective plate and/or the inner-material impacting protective plate and/or the other material falling into the protective plate travel groove through elastic deformation, and the elastomer absorbs the impact counterforce of the outer-layer material impact mechanism and/or the inner-layer material impact mechanism through elastic deformation, so that safe operation of the whole apparatus is ensured.
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0047]      FIG. 1  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 1; 
           [0048]      FIG. 2  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 2; 
           [0049]      FIG. 3  is a top view of the small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 2; 
           [0050]      FIG. 4  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 3; 
           [0051]      FIG. 5  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 4; 
           [0052]      FIG. 6  is a profile view of the small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 4 in the A-A direction; 
           [0053]      FIG. 7  is a front view of a connecting rod of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 5; 
           [0054]      FIG. 8  is a front view of a connecting rod of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 6; 
           [0055]      FIG. 9  is a front view of a connecting rod of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 7; 
           [0056]      FIG. 10  is a front view of an impact head of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 8; 
           [0057]      FIG. 11  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 9; 
           [0058]      FIG. 12  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 10; 
           [0059]      FIG. 13  is a front view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 11; 
           [0060]      FIG. 14  is a top view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 12; 
           [0061]      FIG. 15  is a front view of an outer-layer material impact mechanism of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 13; 
           [0062]      FIG. 16  is a top view of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 14; 
       
    
    
       [0063]    In which:  1 , impact power device;  2 , impact head;  3 , impact power box;  4 , impact mechanism;  5 , guide mechanism;  6 , box body;  7 , central shaft;  8 , driving gear;  9 , transmission gear;  10 , crankshaft  11 , connecting rod;  12 , impact guide member,  13 , plug hammer;  14 , plug rod;  15 , damage-proof power impact member mechanism;  16 , guide supporting member;  17 , guide body;  18 , lubricating liquid passage;  19 , impact teeth;  20 , rack;  21 , water spray mechanism;  22 , machine body;  23 , traveling part;  24 , lifting mechanism;  25 , rotary disk;  26 , telescopic rotary single rocker arm mechanism;  27 , bent single rocker arm mechanism;  28 , outer-layer material impact mechanism;  29 , inner-layer material impact mechanism;  30 , outer-material impacting teeth;  31 , outer-material impacting tooth holder;  32 , outer-material impacting protective member;  33 , inner-material impacting teeth;  34 , inner-material impacting tooth holder,  35 , inner-material impacting protective member;  36 , protective plate travel groove; and  37 , elastomer. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0064]    The present invention will be further described below in combination with the accompanying drawings. 
       Embodiment 1 
       [0065]      FIG. 1  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads in embodiment 1. The small-resistance and high-efficiency digging apparatus with multiple layers of impact heads includes an impact power device  1  and impact heads  2 , wherein the impact heads  2  are arranged at two ends of the impact power device  1 , two impact heads  2  are arranged at each end of the impact power device  1 , and the two impact heads  2  are arranged vertically, so as to increase the digging height. 
         [0066]    The impact heads  2  may be arranged at one end of the impact power device  1 . 
         [0067]    More than two impact heads may be arranged at each end of the impact power device  1 . 
         [0068]    The impact heads  2  may be arranged bilaterally, so as to increase the digging width. 
       Embodiment 2 
       [0069]      FIG. 2  and  FIG. 3  show a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 2, which includes an impact power device  1 , wherein the impact power device  1  is an impact power box  3 ; the impact power box  3  includes an impact mechanism  4 , a guide mechanism  5  and a box body  6 ; the impact mechanism  4  is an electric impact mechanism, and the electric impact mechanism includes a central shaft  7 , a driving gear  8 , a transmission gear  9 , a crankshaft  10  and a connecting rod  11 ; the box body  6  supports the central shaft  7 , the driving gear  8  is arranged on the central shaft  7 , the box body  6  supports the crankshaft  10 , the transmission gear  9  is arranged on the crankshaft  10  and separately connected with the crankshaft  10 , the driving gear  8  is engaged with the transmission gear  9 , one end of the connecting rod  11  is connected with the crankshaft  10 , and the other end of the connecting rod  11  is connected with an impact head  2 , and the box body  6  supports the guide mechanism  5  which includes an impact guide member  12 ; impact heads  2  are arranged at two ends of the impact guide member  12 , and the impact guide member  12  is separately connected with the impact heads  2 ; and the central shaft  7  drives the driving gear  8  to rotate, the driving gear  8  drives the transmission gear  9  to rotate, the transmission gear  9  drives the crankshaft  10  to rotate, the crankshaft  10  drives the connecting rod  11  to reciprocate, the connecting rod  11  drives the impact heads  2  to reciprocate, and the impact heads  2  are guided by the impact guide member  12  to reciprocate. The impact power device  1  may be an impact power support. 
         [0070]    The impact mechanism  4  may be a hydraulic impact mechanism or a pneumatic impact mechanism. 
         [0071]    The driving wheel  8  may be integrated with the central shaft  7 . 
         [0072]    The transmission gear  9  may be integrated with the crankshaft  10 . 
         [0073]    The impact guide member  12  may be separated from or integrated with the impact heads  2 . 
         [0074]    The crankshaft  10  includes two eccentric shafts. 
         [0075]    Others are the same as those in embodiment 1. 
       Embodiment 3 
       [0076]      FIG. 4  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 3. The impact power device  1  includes a box body  6 , plug hammers  13  and a control valve, wherein the box body  6  includes two cavities, two plug hammers  13  are arranged in the two cavities, each plug hammer  13  includes a plug rod  14 , a damage-proof power impact member mechanism  15  is arranged at one end of the plug rod  14 , the control valve controls liquid, the liquid drives the two plug hammers  13  to reciprocate, the two plug hammers  13  drive two impact heads  2  to reciprocate, and the two cavities are arranged vertically, so as to increase the digging height. 
         [0077]    The control valve may also control gas, and the gas drives the plug hammers  13  to reciprocate. 
         [0078]    The two cavities may also be arranged bilaterally, so as to increase the digging width. 
         [0079]    Others are the same as those in embodiment 1. 
       Embodiment 4 
       [0080]      FIG. 5  and  FIG. 6  show a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 4. The impact power device  1  includes a guide mechanism  5 , wherein the guide mechanism  5  is a rolling friction guide mechanism and includes impact guide members  12 , a guide supporting member  16  and a guide body  17 ; the guide supporting member is integrated with the box body  6 , the guide body  17  is arranged between the guide supporting member  16  and the impact guide members  12 , two impact heads  2  move in a front-and-back staggered manner, the impact guide members  12  which are adjacent to the two impact heads  2  and move in a front-and-back staggered manner share one guide body  17  so as to save the space, and the guide body is a waist drum wheel type rolling guide body. 
         [0081]    The guide mechanism  5  may also be a suspended friction guide mechanism. 
         [0082]    The guide body  17  may also be a suspended guide body or a rolling guide body. 
         [0083]    The rolling guide body may also be a spherical, elliptical, dumbbell-shaped, cylindrical, conical, circular, roller type, table column type, table ball type, table drum type, groove-shaped drum type, groove-shaped column type, groove-shaped ball type, groove-shaped roller type, groove-shaped elliptical, shaft-carrying, perforated, multi-edge key type, multi-edge sleeve type, rolling drum type, ball type, rolling needle type, drum type, linear bearing type rolling guide body or the like. 
         [0084]    The suspended guide body may be a suspended liquid guide body or a suspended gas guide body or a suspended magnetic guide body. 
         [0085]    Others are the same as those in embodiment 1. 
       Embodiment 5 
       [0086]      FIG. 7  shows a connecting rod  11  of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 5. A damage-proof power impact member mechanism  15  is arranged at one end of the connecting rod  11 , the damage-proof power impact member mechanism  15  is a buffering damage-proof power impact member mechanism which is a disk spring, and the disk spring absorbs and decomposes the impact counterforce by buffering, so as to prevent the impact counterforce from damaging the impact power device. 
         [0087]    The damage-proof power impact member mechanism  15  may also be a rotary or split damage-proof power impact member mechanism. 
         [0088]    The rotary damage-proof power impact member mechanism may be a joint bearing or a steering connector or a ball cage type universal joint or a cross universal joint or a bulb catching groove type universal joint or an arc-shaped catching groove type universal joint. 
         [0089]    Others are the same as those in embodiment 1. 
       Embodiment 6 
       [0090]      FIG. 8  shows a connecting rod  11  of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 6. A damage-proof power impact member mechanism  15  is arranged at one end of the connecting rod  11 , the damage-proof power impact member mechanism  15  is a buffering damage-proof power impact member mechanism which is a polyurethane spacer, the polyurethane spacer absorbs and decomposes the impact counterforce by buffering so as to prevent the impact counterforce from damaging the impact power device, and a lubricating liquid passage  18  is formed in the connecting rod  11 . 
         [0091]    Others are the same as those in embodiment 1. 
       Embodiment 7 
       [0092]      FIG. 9  shows a connecting rod  11  of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 7. A damage-proof power impact member mechanism  15  is arranged at one end of the connecting rod  11 , the damage-proof power impact member mechanism  15  is a buffering damage-proof power impact member mechanism which is a spring, and the spring absorbs and decomposes the impact counterforce by buffering, so as to prevent the impact counterforce from damaging the impact power device. 
         [0093]    Others are the same as those in embodiment 1. 
       Embodiment 8 
       [0094]      FIG. 10  shows an impact head of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 8. The impact head includes impact teeth  19  and a rack  20 , wherein the impact teeth  19  are arranged in a step shape on the rack  20  to form a step-type impact head, so as to impact the material layer into a step shape and break the pressure stress of a material layer, the step-type impact head continuously impacts the step-shaped material layer, so as to reduce the impact resistance and increase the digging depth; the step-shaped material layer is dug to lump granularity suitable for transport and use during the next impact; and a water spray mechanism  21  is arranged on the rack. 
         [0095]    Others are the same as those in embodiment 1. 
       Embodiment 9 
       [0096]      FIG. 11  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 9, which includes an impact power device  1 , impact heads  2 , a machine body  22 , a traveling part  23  and a lifting mechanism  24 , wherein the lifting mechanism  24  is a rocker arm which is a four-link rocker arm mechanism, one end of the rocker arm is arranged on the machine body  22 , the other end of the rocker arm is connected with the impact power device  1 , the traveling part  23  drives the machine body  22  to travel, and the machine body  22  drives the impact power device  1  to travel. 
         [0097]    The lifting mechanism  24  may be a vertical lifting mechanism, or a rocker arm or translation lifting mechanism. 
         [0098]    Others are the same as those in embodiment 1. 
       Embodiment 10 
       [0099]      FIG. 12  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 10. The machine body  22  includes a rotary disk  25  which is arranged at the front end of the upper part of the machine body  22 , the rocker arm is arranged on the rotary disk  25 , the rotary disk  25  drives the rocker arm to rotate, the rocker arm drives the impact power device  1  to rotate, the rocker arm is a single rocker arm mechanism, and the single rocker arm mechanism is a telescopic rotary single rocker arm mechanism  26 . 
         [0100]    The single rocker arm mechanism may also be a rotary or telescopic or bent single rocker arm mechanism. 
         [0101]    Others are the same as those in embodiment 1. 
       Embodiment 11 
       [0102]      FIG. 13  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 11. The traveling part  23  includes a rotary disk  25  which is arranged at the upper part of the traveling part  23  at the lower part of the machine body  22 , one end of the rocker arm is arranged on the machine body  22 , the other end of the rocker arm is connected with the impact power device  1 , the rocker arm is a bent single rocker arm mechanism  27 , the rotary disk  25  drives the machine body  22  to rotate, the machine body  22  drives the impact power device  1  to rotate, and each impact head  2  is supported and guided by more than two impact guide members  12  to form a multi-point supporting structure so as to centralize the impact direction of the impact head  2 . 
         [0103]    Others are the same as those in embodiment 1. 
       Embodiment 12 
       [0104]      FIG. 14  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 12. Each impact head  2  includes an outer-layer material impact mechanism  28  and an inner-layer material impact mechanism  29 , and the outer-layer material impact mechanism  28  is arranged close to the inner-layer material impact mechanism  29 ; the outer-layer material impact mechanism  28  includes outer-material impacting teeth  30 , an outer-material impacting tooth holder  31  and an outer-material impacting protective member  32 ; the outer-material impacting tooth holder  31  is separately connected with the outer-material impacting teeth  30 ; the inner-layer material impact mechanism  29  includes inner-material impacting teeth  33 , an inner-material impacting tooth holder  34  and an inner-material impacting protective member  35 ; the inner-material impacting tooth holder  34  is separately connected with the inner-material impacting teeth  33 ; the outer-material impacting protective member  32  is separately connected with the outer-material impacting tooth holder  31 , and the inner-material impacting protective member  35  is separately connected with the inner-material impacting tooth holder  34 ; the impact power box  3  drives the outer-layer material impact mechanism  28  and the inner-layer material impact mechanism  29  to reciprocate; and the outer-material impacting protective member  32  and the impact power box  3  as well as the inner-material impacting protective member  35  and the impact power box  3  are partially superposed all the time, so as to prevent a material from entering the outer-material impacting protective member  32  and the impact power box  3  and/or prevent a material from entering the inner-material impacting protective member  35  and the impact power box  3 ; the shape and/or arrangement of the outer-material impacting teeth  30  are favorable for impacting the outer material of a material layer to be dug, gaps between the outer-material impacting teeth  30  are favorable for the flowing of the material fallen because of impaction of the inner-layer material impact mechanism  29  thereto or the outer-layer material impact mechanism  28  is provided with a discharging hole for discharging the material fallen because of impaction of the inner-layer material impact mechanism  29 , and the inner-layer material impact mechanism  29  is matched with the outer-layer material impact mechanism  28  to realize impact blanking and discharging, so that the continuously dug material may smoothly pass through the machine body  22 . 
         [0105]    Others are the same as those in embodiment 1. 
       Embodiment 13 
       [0106]      FIG. 15  shows an outer-layer material impact mechanism of a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 13. The outer-layer material impact mechanism  28  includes outer-material impacting teeth  30 , an outer-material impacting tooth holder  31  and an outer-material impacting protective member  32 , wherein the outer-material impacting teeth  30  are integrated with the outer-material impacting tooth holder  31 , the outer-material impacting protective member  32  is an outer-material impacting protective plate which is arranged around the outer-material impacting tooth holder, and the outer-material impacting protective plate reciprocates along with the outer-material impacting tooth holder  31 . 
         [0107]    Others are the same as those in embodiment 1. 
       Embodiment 14 
       [0108]      FIG. 16  shows a small-resistance and high-efficiency digging apparatus with multiple layers of impact heads described in embodiment 14. The impact power box  3  includes a protective plate travel groove  36 , the outer-material impacting protective member  32  is an outer-material impacting protective plate, the inner-material impacting protective member  35  is an inner-material impacting protective plate, and the adjacent parts of the inner-material impacting protective plate and the outer-material impacting protective plate reciprocate in the protective plate travel groove  36 ; an elastomer  37  is arranged in the protective plate travel groove  36 ; the elastomer  37  shakes off and ejects the material brought by the outer-material impacting protective plate and/or the inner-material impacting protective plate and/or the material falling into the protective plate travel groove  36  through elastic deformation; and the elastomer  37  absorbs the impact counterforce of the outer-layer material impact mechanism  28  and/or the inner-layer material impact mechanism  29  through elastic deformation. 
         [0109]    The elastomer  37  may be arranged at the free end of the outer-material impacting protective plate and/or the free end of the inner-material impacting protective plate. 
         [0110]    Others are the same as those in embodiment 1.