Patent Publication Number: US-10315902-B2

Title: Vehicle with a low gravity center and aerial work platform

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from Chinese Patent Application No. 201610778675.8 filed Aug. 31, 2016, all of which are hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to field of engineering mechanics and more particularly, relates to an engineering work vehicle, and most particularly, relates to a vehicle with a low gravity center and aerial work platform. 
     BACKGROUND OF THE INVENTION 
     Aerial work platform is an advanced aerial working mechanical device, and is capable of significantly improving efficiency, safety, and comfort of operators at height, and is also capable of reducing labor. Accordingly, it is widely employed in developed countries. This aerial work platform is also extensively used in China in many fields such as urban street lamp maintenance, tree trimming or the like. With rapid development of Chinese economy, aerial work platform is increasingly required in many situations such as engineering construction, industry installation, equipment repair, workshop maintenance, ship manufacture, electric power, municipal construction, airport, communications, city park, and transportation. 
     In a conventional aerial work platform, an engine, fuel tank and hydraulic tank are all laterally mounted on a turret. However, as the turret is disposed on a vehicle frame of the vehicle, a relatively high gravity center is resulted for the vehicle. This restricts off-road ability and grade-ability of the aerial work platform. In addition, this also restricts horizontal reach of the aerial work platform. In other words, the horizontal reach of an operation platform is limited. 
     However, the aerial work platform often runs in a complicated environment and accordingly, it is required to make some improvement upon structure and/or installation manner of relevant components of the vehicle. Therefore, there is need for providing an aerial work platform to overcome drawbacks of above prior art aerial work platform. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to address above problems and provide a vehicle with a low gravity center and aerial work platform. In current invention, power system, fuel tank and hydraulic tank are mounted at a side of a vehicle frame of a vehicle to lower gravity center of the vehicle and entire aerial work platform, enhance off-road capability and grade-ability of the aerial work platform, and increase horizontal reach of the aerial work platform, thereby enlarging working range of the aerial work platform. 
     To realize this object, the present invention proposes a vehicle with a low gravity center for an aerial work platform. The vehicle includes a vehicle frame, a power system, a fuel tank, and a hydraulic tank all of which are mounted at a side of the frame. 
     Specifically, the power system, fuel tank, and hydraulic tank are all disposed at a side of the vehicle frame along a length direction. 
     Furthermore, a first box and a second box are installed on two sides of the frame along the length direction of the frame respectively. The power system is contained in the first box, whereas the fuel tank and hydraulic tank are contained in the second box. 
     Specifically, the power system includes an engine located in the first box and secured onto the vehicle frame through a bracket. 
     Preferably, a damping device is disposed at a location where the engine and bracket are connected together. 
     Preferably, the fuel tank, hydraulic tank, and second box are integrally formed. 
     Furthermore, a control box is disposed on the second box and is foldable into and out of the second box. 
     Furthermore, the power system further includes a cooling component, a fuel delivery component, and an intake-exhaust component. 
     Correspondingly, the present invention further provides an aerial work platform including a vehicle with lower gravity center as mentioned above, a telescopic transmission component pivotablly mounted on the vehicle, and an operation platform disposed on a distal end of the telescopic transmission component. 
     Furthermore, a turret is disposed on the vehicle frame of the vehicle. One end, away from the operation platform, of the telescopic transmission component, is pivotablly connected with the turret through a supporting arm. The operation platform is connected with the telescopic transmission component via a telescopic connection component. A supporting member is disposed between the supporting arm and telescopic transmission component, and similarly, another supporting member is placed between the telescopic transmission component and telescopic connection component. 
     Compared with prior art techniques, the present invention brings the following good effects: 
     In present invention, as the power system, fuel tank, and hydraulic tank are all located at one side of the vehicle frame, and the total weight of these and other related components amounts to 1000 Kg-1500 Kg after injection of related materials, the gravity center of the aerial work platform is able to be lowered by 0.4 m-0.6 m, thus strongly improving off-road performance and grade-ability of the entire platform. Accordingly, the aerial work platform is able to run under various complex environments. In addition, the horizontal reach of the aerial work platform is also increased, and work range of the same is also extended. 
     Correspondingly, the power system is disposed in the first box, while the fuel tank and hydraulic tank is disposed in the second box. The first and second boxes are able to protect relevant components therein effectively, avoiding collision of these components with external objects and thereby avoiding damages to the same. This also decreases dust and aging of the components and therefore, further reduces cost of maintenance and repair, and extends life of the components. Moreover, as a damping device is provided between the engine and bracket, damage to the engine due to vehicle shake during running of the aerial work platform is effectively prevented, thus further reducing cost of maintenance and repair, and extending life of the components. Moreover, as the fuel tank, hydraulic tank, and second box are integrally formed, manufacture and installation is convenient, the entire construction is simple and compact, and appearance is good. 
     In a summary, the inventive aerial work platform has better off-road performance and grade-ability, can work in complicated environment, and owns a longer horizontal reach and larger working range. Moreover, maintenance and repair cost is decreased, lifetime is extended, integrity is higher and appearance looks better. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic view of an aerial work platform in accordance with a typical embodiment of the invention; 
         FIG. 2  shows a view of a vehicle of  FIG. 1 ; 
         FIG. 3  illustrates another view of the vehicle of  FIG. 1  showing internal construction of a second box; 
         FIG. 4  illustrates another view of the vehicle of  FIG. 1  showing internal construction of a first box; 
         FIG. 5  illustrates another view of the vehicle of  FIG. 1  showing internal construction of an engine and second box; 
         FIG. 6  shows a partially enlarged view of portion M of  FIG. 1 ; 
         FIG. 7  illustrates another view of a front component of the aerial work platform of  FIG. 1 , the front component including a telescopic connection component, an operation platform, and relevant connection components; 
         FIG. 8  shows a schematic view of a telescopic transmission component of the aerial work platform of  FIG. 1 ; 
         FIG. 9  shows a partially enlarged view of portion A of  FIG. 8 ; 
         FIG. 10  shows a partially enlarged view of portion B of  FIG. 8 ; 
         FIG. 11  shows a view of the telescopic transmission component of  FIG. 8  in an expanded configuration; 
         FIG. 12  denotes a structural view of internal major transmission members of the telescopic transmission component of  FIG. 8 , the major transmission members including a first sprocket wheel, a second sprocket wheel, a rope-expanding chain, a rope-retracting chain, and a retractable cylinder; 
         FIG. 13  shows a schematic view of internal major transmission members of the telescopic transmission component of  FIG. 8 ; 
         FIG. 14  shows a schematic view of internal major transmission members of the telescopic transmission component of  FIG. 8 ; 
         FIG. 15  denotes a structural view of the retractable cylinder of the telescopic transmission component of  FIG. 8 ; 
         FIG. 16  shows a partially enlarged view of portion C of  FIG. 15 ; and 
         FIG. 17  illustrates a view of a front component of an aerial work platform according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be further described below with reference to accompanied drawings and exemplary embodiments. Here, identical numerals represent the identical components. In addition, detailed description of prior art will be omitted if it is unnecessary for illustration of the features of the present invention. 
       FIGS. 1-16  show a typical embodiment of an aerial work platform of the present invention. The aerial work platform includes a vehicle  1 , a telescopic transmission component  2  pivotablly installed on the vehicle  1 , and an operation platform  3  connected to a distal end of the telescopic transmission component  2  via a telescopic connection component  5 . 
     It is noted that the vehicle  1  includes a vehicle frame  102 , a driving system, a fuel tank  121 , and a hydraulic tank  122 . The driving system includes a power system, a transmission mechanism, a control system, a driving mechanism, and a wheel assembly. The power system, fuel tank  121  and hydraulic tank  122  are all installed at a side of the frame  102  along a length direction of the frame  102 . A turret  101  is provided on an upper end of the frame  102  of the vehicle  1 . One end, away from the operation platform  3 , of the telescopic transmission component  2 , is pivotablly connected with the turret  101  through a supporting arm  4 . The operation platform  3  is coupled with the telescopic transmission component  2  by means of a telescopic connection component  5 . A supporting member (for example a cylinder with kinds of functions) is disposed between the supporting arm  4  and telescopic transmission component  2 , and similarly, another supporting member is placed between the telescopic transmission component  2  and telescopic connection component  5 . 
     Reference is made to  FIGS. 1-5 . Fixed to two lateral sides of the vehicle frame  102  respectively along its length direction are a first box  11  and a second box  12 . The power system is contained in the first box  11 , whereas the fuel tank  121  and hydraulic tank  122  are located in the second box  12 . The power system includes an engine  112 , a cooling component, a fuel delivery component, and an intake-exhaust component. The engine  112  is positioned in the first box  11  and is mounted onto the frame  102  by a bracket  114 . A damping device (not shown) is disposed at a location where the engine  112  and bracket  114  are connected together. The fuel tank  121 , hydraulic tank  122 , and second box  12  are integrally formed. In addition, a control box  123  is disposed on the second box  12  and is foldable into and out of the second box  12 . The control box  123  is electrically connected with the control system. Specifically a turning opening is defined at a side of the second box  12  for turning the control box  123  into and out of the second box  12 . An upper edge (See orientation of the control box in  FIG. 3  of control box  123 ) is hinged to an upper edge of the turning opening. The height of the control box  123  relative to the ground is such designed that, when the control box  123  is rotated out of the second box  12  through the turning opening, an operator standing on the ground will be able to comfortably get access to the control box  123 . In addition, relevant control devices may be provided on the operation platform  3  and be coupled with the control system electrically. 
     In a summary, as the power system, fuel tank  121 , and hydraulic tank  122  are all located at a side of the vehicle frame  102  of the vehicle  1 , and the total weight of these and other related components amounts to 1000 Kg-1500 Kg after injection of related materials, the gravity center of the aerial work platform is able to be lowered by 0.4 m-0.6 m, thus strongly improving off-road performance and grade-ability of the entire platform. Accordingly, the aerial work platform is able to run under various complex environments. In addition, the horizontal reach of the aerial work platform is also increased, and work range of the same is also extended. 
     The telescopic connection component  5  includes an outer arm  51 , an inner arm  52  slidably disposed inside the outer arm  51  and capable of being moved out from one end of the outer arm  51 , and a forearm telescopic cylinder  53  disposed between the outer arm  51  and inner arm  52 . 
     It is noted that the forearm telescopic cylinder  53  includes a cylinder body (not shown) and a piston rod (not shown) slidably disposed into the cylinder body. Preferably, the cylinder body is secured onto an outer wall of the outer arm  51 , and an extension end of the piston rod is secured onto an outer wall of the inner arm  52 . 
     A first levelling cylinder  55  is disposed between the telescopic transmission component  2  and telescopic connection component  5 . A forearm head  54  is hinged to one end, which is connected to the telescopic transmission component  2 , of the telescopic connection component  5 . One end of the first levelling cylinder  55  is hinged to the telescopic transmission component  2 , while the other end thereof is hinged to the forearm head  54 . The telescopic connection component  5  further includes a forearm luffing cylinder  57  one end of which is hinged to the forearm head  54 , while the other end thereof is hinged to the outer wall of the outer arm  51 . By this means, the forearm head  54 , outer arm  51  and forearm luffing cylinder  57  constitute a triangle luffing mechanism. 
     It is noted that the forearm head  54 , outer arm  51  and telescopic transmission component  2  are hinged together by a pin  512 . The first levelling cylinder  55 , forearm head  54 , forearm luffing cylinder  57  and outer arm  51  constitute a four-bar linkage. Moreover, the first levelling cylinder  55  may operate electrically or hydraulically. In case operating under electric manner, an angle sensor (not shown) matched with the first levelling cylinder  55  is installed on the pin  512  which hinges the forearm head  54 , outer arm  51  and telescopic transmission component  2  together. In case operating under hydraulic manner, a hydraulic levelling device matched with the first levelling cylinder  55  is disposed on the telescopic transmission component  2 . Preferably, the first levelling cylinder  55  works in electrical levelling manner. 
     Here, the forearm head  54  may be leveled by pushing and pulling motion of the first levelling cylinder  55  upon the head  54 . Specifically, an angle sensor installed on the forearm head  54  sets an angle of the head  54  as zero. During luffing of the telescopic transmission component  2 , the forearm head  54  will tilt accordingly. As a result, angle signal of the forearm head  54  will be sent to a corresponding controller through the angle sensor. After receiving the signal, the controller will generate a corresponding command to cause telescopic motion of the first levelling cylinder  55 , thereby realizing levelling of the forearm head  54 . In other words, the forearm head  54  is controlled to be oriented at its predefined zero angle. In addition, up and down luffing of the telescopic connection component  5  may also be realized by telescopic movement of the forearm luffing cylinder  57 . 
     Furthermore, a third levelling cylinder  58  is disposed between the telescopic connection component  5  and operation platform  3 . One end of the third levelling cylinder  58  is hinged to the inner arm  52 , whereas the other end thereof is hinged to a rotary cylinder  33  secured onto the operation platform  3 . 
     Preferably, a second levelling cylinder  56  is positioned between the forearm head  54  and telescopic connection component  5 . One end of the second levelling cylinder  56  is hinged to the forearm head  54 , while the other end thereof is hinged to the outer wall of the outer arm  51 . A cavity of the second levelling cylinder  56  communicates with a cavity of the third levelling cylinder  58  by means of an oil tube. 
     It is noted that arrangement of the second levelling cylinder  56  and third levelling cylinder  58  avoids tilting of the operation platform  3  during luffing of the telescopic connection component  5 . In other words, the operation platform  3  is always maintained at a horizontal location during luffing of the telescopic connection component  5 . Accordingly, the second levelling cylinder  56  and third levelling cylinder  58  have a second level of levelling function (the first levelling cylinder  55  and associated device realize a first level of levelling function). As the cavity of the second levelling cylinder  56  communicates with that of the third levelling cylinder  58  by an oil tube, levelling may be achieved by adjusting telescopic motion of the second and third levelling cylinders  56  and  58 . The detailed levelling processing is described below. When the telescopic connection component  5  luffs upwardly, a telescopic rod of the forearm luffing cylinder  57  comes out and at the same time, a telescopic rod of the second levelling cylinder  56  also comes out. At this time, hydraulic medium inside a rod chamber of the second levelling cylinder  56  flows under pressure into a rod chamber of the third levelling cylinder  58 . Next, a telescopic rod of the third levelling cylinder  58  retracts, and hydraulic medium contained inside the non-rod chamber of the third levelling cylinder  58  flows into a non-rod chamber of the second levelling cylinder  56  through an oil tube so as to realize levelling by balancing pressure inside relevant chambers of the second and third levelling cylinders  56  and  58 . This principle also applies when the telescopic connection component  5  luffs downwardly except for flowing direction of hydraulic medium and movement direction of relevant components. Here, cross section areas of the cylinders, telescopic rods of the second and third levelling cylinders  56  and  58 , and traveling distances of the telescopic rods thereof are predefined and matched among each other. 
     Reference is made to  FIGS. 1 and 6-16  illustrating a typical embodiment of a telescopic transmission component of the aerial work platform of the invention. The telescopic transmission component  2  includes a base arm  21 , a second arm  22 , a third arm, a telescopic cylinder  24 , a rope-expanding chain  27 , and a rope-retracting chain  28 . 
     The second arm  22  is inserted into the base arm  21  and is able to move out of the base arm  21  (See an upper portion of  FIG. 11 ). The third arm  23  is inserted into the second arm  22  and is capable of coming out of an extension end of the same (See an upper portion of  FIG. 11 ). 
     The telescopic cylinder  24  includes a cylinder barrel  241  secured onto the second arm  22  and a telescopic rod  242  inserted into the barrel  241 . The telescopic rod  242  has a hollow arrangement  247  communicating with a cavity of the cylinder barrel  241 . An oil guiding tube  245  is provided into the hollow arrangement  247  of the telescopic rod  242 , and the extension end of the telescopic rod  242  is secured onto the base arm  21  (See a lower portion of  FIG. 13 ). Preferably, an end surface of the extension end of the telescopic rod  242  is fixed to the base arm  21  through a mounting plate  8 . A connection portion is provided on the cylinder barrel  241  at a location adjacent to the extension end of the telescopic rod  242  for securing the barrel  241  to the second arm  22 . The connection portion may in the form of an axle hole. That is, the cylinder barrel  241  may be mounted on the second arm  22  by inserting a pin into said axle hole. Of course, the connection portion of the barrel  241  may also be designed to locate at other positions of the barrel  241 , for example at a middle position. 
     Moreover, a first sprocket wheel  25  is provided on the telescopic cylinder  24 , a second sprocket wheel  26  is provided on the second arm  22 , and the second sprocket wheel  26  is closer to the extension end of the cylinder barrel  241  than does the first sprocket wheel  25 . One end of the rope-expanding chain  27  is attached onto the base arm  21 , while the other end thereof runs around the first sprocket wheel  25  and then is attached onto the third arm  23 . In other words, the two ends of the rope-expanding chain  27  are both located below the first sprocket wheel  25  (See orientation of figures). One end of the rope-retracting chain  28  is attached onto the third arm  23 , while the other end thereof runs around the second sprocket wheel  26  and then is attached onto the base arm  21 . In other words, the two ends of the rope-retracting chain  28  are both located above the second sprocket wheel  26  (See orientation of figures). Preferably, the first sprocket wheel  25  is located on a cylinder head, which cylinder head is located at one end away from an extension end, of the telescopic cylinder  24 . The second sprocket wheel  26  is located on the second arm  22  at a location adjacent to the extension end of the telescopic rod  242 . By this manner, the first and second sprocket wheels  25  and  26  are capable of being positioned above and below the cylinder barrel  241  (See orientation of figures). This ensures stable movement of the cylinder barrel  241  and accordingly, it also ensures stable rotation and telescopic motion of relevant components. Of course, the first and second sprocket wheels  25  and  26  may also be positioned at other suitable locations. For instance, the first sprocket wheel  25  may be located at a middle area of the cylinder barrel  241 , and the second sprocket wheel  26  may be placed on the second arm  22  at a location close to a middle portion of the cylinder barrel  241 . 
     As shown in  FIGS. 15-16 , an inner cavity of the cylinder barrel  241  of the telescopic cylinder  24  is separated to form a rod chamber  244  and a non-rod chamber  243 . In other words, partial space of the inner cavity of the barrel  241  overlaps the telescopic rod  242  and thus forms the rod chamber  244 . Partial space of the inner cavity of the barrel  241  doesn&#39;t overlap the rod  242  and locates at a upper right side (See  FIG. 16 ) of a distal end of the telescopic rod, and accordingly, forms the non-rod chamber  243 . The hollow arrangement  247  of the telescopic rod  242  communicates with the rod chamber  244  via a connection path  246 . The hollow arrangement  247  of the rod  242  together with the oil guiding tube  245  inside the arrangement  247  is communicated with an external oil tube. 
     Furthermore, one end of the rope-retracting chain  28  is attached onto the third arm  23  by means of a chain connection member  29 , similarly, one end of the rope-expanding chain  27  is also attached onto the third arm  23  by means of the chain connection member  29 , and the two ends are located at two sides of the chain connection member  29 . By this manner, motions of the rope-expanding chain  27 , rope-retracting chain  28  and third arm  23  are coordinated among each other. Alternatively, the rope-expanding chain  27  and rope-retracting chain  28  may be connected to the third arm  23  with different connective members. 
     Moreover, a chain detection device is provided on the rope-expanding chain  27  for real time detecting status of related chain. When a chain is broken or exceeds a predefined loose value, the chain detection device will generate alert signals to guarantee safety of the telescopic transmission component  2 , and further guarantee safety of operators and other staff. In particular, the chain detection device may be disposed on the rope-expanding chain  27  at one end thereof where the chain  27  is connected to the base arm  21 . 
     Preferably, all of the base arm  21 , second arm  22  and third arm  23  are of hollow arrangement. It is noted that these arms are by no means limited to this hollow arrangement, and in fact they may be of other constructions. 
     Furthermore, these hollow arrangements of the base arm  21 , second arm  22  and third arm  23  form a telescopic cavity into which the telescopic cylinder  24 , first sprocket wheel  25 , second sprocket wheel  26 , rope-expanding chain  27  and rope-retracting chain  28  are received, thus leading to a compact structure for the telescopic transmission component  2 , and further reducing wear and aging of the components, thereby extending lifetime. This also reduces repair and maintenance frequency and makes it more convenient to repair and maintain the same, thus decreasing related costs. In addition, to certain extent these components are not exposed outside and accordingly, risk of operators being injured due to unintentional collision with the components is also reduced. Of course, it is also feasible to place the telescopic cylinder  24 , first sprocket wheel  25 , second sprocket wheel  26 , rope-expanding chain  27  and rope-retracting chain  28  outside the telescopic cavity (that is, place them onto the outer walls of the base arm  21 , second arm  22  and third arm  23 ). 
     In a summary, as the telescopic rod  242  is secured onto the base arm  21 , when driven by suitable liquid medium, the cylinder barrel  241  will move upwardly together with the second arm  22  such that the second arm  22  will move out of the base arm  21 . In turn, under the traction of the rope-expanding chain  27  and first sprocket wheel  25 , the third arm  23  is pulled to move out of an upper end of the second arm  22 . With continuous injection of the liquid medium into the cylinder barrel  241 , the second arm  22  and third arm  23  will continue to move toward the upper end until desired travel distance or maximum predefined distance is reached. During this movement, the first sprocket wheel functions as a movable pulley, and in this situation, displacement of the third arm  23  relative to the base arm  21  is two times as long as a travel distance of the cylinder barrel  241  (the distance of the second arm  22  with respect to the base arm  21 ). In this case, telescopic distance is certainly extended. 
     When oil enters the rod chamber  244  of the cylinder barrel  241  through the hollow arrangement  247  of the telescopic rod  242 , the barrel  241  will drive the second arm  22  to move together downwardly such that the second arm  22  will retract from the upper end of the base arm  21 . In turn, the third arm  23  will retract into the second arm  22  when driven by the rope-retracting chain  28  and second sprocket wheel  26 . With continuous oil injection into the telescopic rod  242 , the second arm  22  and third arm  23  will continuously retract towards a low end until a desired retracting location or complete retracting location is reached. During this retraction, the second sprocket wheel  26  works as a movable pulley such that the displacement of the third arm  23  relative to the base arm  21  is two times as long as the travel distance of the cylinder barrel  241  (that is, the distance of the second arm  22  relative to the base arm  21 ). 
     Specifically, please refer to  FIG. 1  and other related figures, the third arm  23  is hinged to the operation platform  3  by said telescopic connection component  5 . In other words, the third arm  23  is hinged to the outer arm  51  of the telescopic connection component  5 , and the inner arm  52  of the component  5  is connected with the operation platform  3 . The telescopic connection component  5  helps the operation platform  3  move further along a horizontal direction. The base arm  21  is hinged to the vehicle  1  by the supporting arm  4  which is movably connected with relevant component of the vehicle  1 . In addition, a luffing cylinder  6  is disposed between the base arm  21  and supporting arm  4 . By this manner, the base arm  21 , supporting arm  4  and luffing cylinder  6  connected therewith also together define a reliable triangle construction. This makes sure that the aerial work platform bears more stability and security. 
     When the aerial work platform requires extending its arms, the second and third arms  22 ,  23  are controlled to extend of the telescopic transmission component  2 . At this time, the operation platform  3  coupled with the telescopic transmission component  2  will also be extended when driven by the third arm  23 . At this time, relevant cylinder  6 , supporting arm  4  and telescopic connection component  5  are also controlled to adjust angle or location of relevant arms until the operation platform  3  moves to a predefined working location or a maximum extension distance is reached. 
     Similarly, when the aerial work platform requires withdrawing its arms, the second and third arms  22 ,  23  of the telescopic transmission component  2  are controlled to retract. At this time, the operation platform  3  coupled with the telescopic transmission component  2  will also be retracted when driven by the third arm  23 . At this time, relevant cylinder  6 , supporting arm  4  and telescopic connection component  5  are also controlled to adjust angle or location of relevant arms until the operation platform  3  moves to a predefined working location or returns to its original location without extension. 
     Moreover, please refer to  FIG. 17  which illustrates another example of an aerial work platform of the invention. This example is different from the above example in that: a luffing cylinder  57  in place of relevant first level of levelling components of the above example and serving as a supporting member is disposed between the telescopic transmission component  2  and telescopic connection component  5 ; and the third levelling cylinder  58  works in an electrical levelling manner other than hydraulic levelling manner as described in above example, that is, an angle sensor  59  cooperating with the third levelling cylinder  58  is provided on the rotary cylinder  33 . 
     When in operation, up and down luffing action of the telescopic connection component  5  is realized by telescopic motion of the luffing cylinder  57  located between the telescopic transmission component  2  and telescopic connection component  5 . Levelling of the operation platform is conducted by telescopic motion of the third levelling cylinder  58 , thus ensuring all time horizontal orientation of the platform. 
     Specifically, an angle sensor  59  installed on the rotary cylinder  33  sets a location of the operation platform  3  as zero. During luffing motion of the telescopic connection component  5 , this angle sensor  59  will transmits electrical signals to a corresponding controller which when receives the signals, will send control command to cause telescopic motion of the third levelling cylinder  58 , hence realizing levelling of the operation platform. in other words, it is maintained that the operation platform is always in its zero location. 
     Summarily, the inventive aerial work platform has better off-road performance and grade-ability, can work in complicated environment, and owns a longer horizontal reach and larger working range (it is extended by at least 1.2 meters than a prior art aerial work platform). Moreover, maintenance and repair cost is decreased, lifetime is extended, integrity is higher and appearance looks better. 
     Though various embodiments of the present invention have been illustrated above, a person of the art will understand that, variations and improvements made upon the illustrative embodiments fall within the scope of the present invention, and the scope of the present invention is only limited by the accompanying claims and their equivalents.