【正文】 ces the inside discharge of the cylinder. But the framework design is difficult. It makes the hydraulic system plex and costs a lot, so it is not monly used. See Patent: US4056283.圖5The single cylinder connecting rod bined type—— it has the stable lifting ability, strong overloading ability and good hydraulic characteristics. It can be changed into different style through changing the fourbar linkage. Mallory type is one of the types and widely used in China because of the characteristics of small cylinder diameters and long cylinder routes. But some types is not widely used because of big cylinder diameters and short cylinder routes. See Patent: US4168861.圖6The multistage cylinder lead straight top type—— is made up of one multistage cylinder whose route can be 5 to 6 meters. It is the simplest lifting mechanism and largely improves the stability of the truck. It is the development direction of the dump truck. But its cost is the most expensive, which restricts its development in China. See Patent: US5033794, US6382731.圖7The future of Dump Trucks in ChinaMost of the dump trucks in China use the single cylinder connecting rod bined type, from the single cylinder centrallymounted straight top type and the multistage cylinder centrallymounted straight top type. The trend of development is the multistage cylinder lead straight top type and the type will be developed, but we can’t see a lot in China. We believe in the distant future it can quickly be developed and used in our country. The front multilevel cylinder lifting mechanism is the leading direction of dump truck manufacturing. For now, the dump trucks in our country are bothered by two main problems: high gravity center and heavy dead weight. To overe these two obstacles, the younger generation and the technical engineers need to work hard to improve the peting ability of our production.All in all, the key point is to improve the quality of our products.（2）專利列表Patent ListPatent No.App TimePatent NameInventorDrawing FiguresBrief DiagramThe TypesUS2094521LIFTING MECHANISM FOR DUMP BODIESF. BISZANTZ et alInvention Patent。Fourbar LinkageUS2593776DUMP BODY TILTING MECHANISMCharles E. Margala et alInvention Patent。Sixbar LinkageUS3172703DUMP MECHANISM FOR TRUCKSJoan A. ByerInvention Patent。Eightbar LinkageUS3620458ALBERT RATH XYSteel Products Ltd. Preston et alUtility Model Patent。Fourbar LinkageUS4049316Lifting mechanisms for truck bodiesMarino Paneda OrdonezInvention Patent。Sixbar LinkageUS4066296Truck bed tilting mechanismLouis M. Ray, Jr. et alInvention Patent。Sixbar LinkageUS4168861Dumphoist conversion systemOllie J. CarrollUtility Model Patent。Sixbar LinkageUS4382632Dumping vehicle stabilizer systemCharlie C. PittsUtility Model Patent。Sixbar LinkageUS4592593Scissor frame lift apparatus for dump trucksGlenn L. ChannellInvention Patent。Sixbar LinkageUS5033794Securing device for dump truckHenry L. VickUtility Model Patent。Sixbar LinkageUS5195385Free ranging bidirectional hydraulic dumping mechanismJerome A. JohnsonUtility Model Patent。Sixbar LinkageUS5513901Hoist mechanismFred P. Smith et aInvention Patent。Sixbar LinkageUS6156596Truck hoistEldon D. JonesUtility Model Patent。Sixbar LinkageUS6663185Tipping trailersRhys William RichardsUtility Model Patent。Fourbar LinkageUS7523994HoistEldon D. JonesUtility Model Patent。Sixbar LinkageUS8157316Translating cargo bedHarlan J. BartelInvention Patent。 considering the demand of huge power, the driving link must be hydraulic.（4）All linkages have to be Revolute Joints except the driving link (the hydraulic cylinder).（4）Box, driving link and the ground could not be in the same kinematic chain circuit to avoid fourbar linkage which may affect lifting quality and stability.A：Following are the 9 possible solutions according to 1 and 2：車身車身車斗車斗車斗車斗車身車身車身車身車斗車斗 a) b) c) d) e) f)車身車身車斗車斗車斗車身Box g) h)i)B：Driving link (Prismatic pair)Following are the 9 possible solutions according to 3, 4 and 5:底盤車斗車斗底盤 A1 A2車斗底盤車斗底盤 A3 B1底盤底盤車斗車斗 B2 B3底盤車斗車斗底盤 B4 C1底盤車斗車斗底盤 C2 C3底盤車斗底盤車斗 D1 D2車斗底盤車斗底盤 D3 D4底盤底盤車斗車斗 E1 E2車斗車斗底盤底盤 E3 E4底盤車斗底盤車斗 F1 F2車斗車斗底盤底盤