Abstract:
Rigidity of a frame of a working vehicle is improved by a simple structure and production costs are reduced by reducing the number of parts of a working vehicle. Pipes  66  are provided on both left and right sides at the center in the front-rear direction of a side frame  62 , and each pipe  66  has a rectangular cross-section and penetrates an intermediate partition in the front-rear direction from a mast section  64  up to a transmission section. Tie-down holes are formed in a front face plate  61  to which the front end of a frame  9  is connected, and a plate  64   b  connected to a side frame  62  is provided at the bottom surface of each mast section  64  protruding outward from the side frame  62 . Tanks installed on the working vehicle are suspended from the plate bodies  64   b , and a lift arm installation boss provided at each mast section  64  is supported at both ends. A U-shaped reinforcement member  81  connects the upper surface of mast partition plate of a mast section  64  and left and right bosses.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a frame structure for a working vehicle. In more detail, the present invention relates to an easy and cheap construction of light and rigid frame of a working vehicle. 
     2. Background Art 
     Conventionally, there is well known a frame of a working vehicle constructed by square pipes, I-shaped steel and the like. The frame of the working vehicle is constructed by I-shaped steel and the like, and various devices are attached to the frame as needed (for example, see the Patent Literature 1). 
     A frame mainly comprising square pipes and I-shaped steel is difficult to be processed so as to require prodigious labor for assembly. Furthermore, high cost is required for production. 
     Patent Literature 1: the Japanese Patent Laid Open Gazette 2004-1769 
     BRIEF SUMMARY OF THE INVENTION 
     Problems to Be Solved by the Invention 
     The purpose of the present invention is to improve the rigidity of a frame of a working vehicle and allowing for easy construction and reduced production cost. 
     When a stay is disposed in each of members for attachment, the number of parts is increased so as to reduce assembly workability. Further, attaching of many members increases weight. These are also problems to be solved. 
     Means for Solving the Problems 
     The above-mentioned problems are solved by the following means. 
     According to the present invention, with regard to a frame structure for a working vehicle including a cross member partitioning an engine disposition part and a transmission attachment part between left and right side frames, and a longitudinal pipe penetrating the cross member is disposed on an inner side surface of each of the side frames from the engine disposition part to the transmission attachment part. 
     A reinforcement member is disposed on a lower surface of each of the side frames from the engine disposition part to the transmission attachment part. 
     A mast section extended outward is disposed in an upper portion of each of the side frames respectively, and a plate body which connects a bottom surface of the mast section to a side surface of the side frame is provided. 
     Each of the mast sections is connected through a mast partition plate to an outer side of corresponding one of front frames respectively touching and fixed to the side frames, and the mast partition plate is fixed thereto with a pair of left and right bosses, which supports both sides of a lift arm, and a U-like reinforcement member connected to the left and right bosses. 
     An inner side surface of each of the mast sections and an upper surface of corresponding one of the side frames are connected to each other by a reinforce plate. 
     A mount of a radiator is disposed between the side frames and a connection member is provided which connects an upper portion of the mount to the reinforce plate. 
     The connection member is constructed integrally with a slide guide of a stay of an engine bonnet. 
     A base of a seat mount is connected to the upper surfaces of the left and right side frames so as to constitute a second cross member. 
     A transmission attachment member is disposed on the inner side surface of each of the side frames at the transmission attachment part, and a reinforcement member substantially triangle shaped when viewed on the side is fixed along a bent part of the lower surface of each of the side frames between the transmission attachment member to the cross member. 
     Each of the transmission attachment members is a laterally turned U-like shape when viewed in plan, and each of rear transaxle casings respectively extended leftward and rightward from the transmission is fixed to a plate member attached to a lower portion of the transmission attachment member. 
     An outer end of each of the rear transaxle casings is connected to a side surface of corresponding one of the side frames through a second plate member. 
     A plate body that is L-like shaped when viewed in front is extended from each of the side frames at the transmission attachment part, and the transmission is fixed through the plate bodies extended from the left and right side frames. 
     A lever stand attached to at least one of the left and right side frames serves as a stay of a rear fender. 
     A hydraulic valve connected to a lever disposed in the lever stand and main electric equipments are intensively attached to the lever stand so as to construct them integrally, whereby the number of parts of the working vehicle is reduced so as to improve workability of the assembly process and to simplify the checking and attachment of the electric equipments. 
     Effect of the Invention 
     According to the frame structure for the working vehicle of the present invention, rigidity of the frame is improved so that intensity of the frame of the working vehicle is improved. Parts requiring high rigidity are reinforced efficiently. The frame is reinforced efficiently with easy construction. 
     According to the frame structure for the working vehicle of the present invention, rigidity of the mast section is improved so that intensity of the frame of the working vehicle is improved. The frame of the working vehicle is rigid enough to bear when a working machine such as a backhoe is attached to the rear portion of the frame. The part requiring high rigidity is reinforced efficiently so as to make the mast section supporting a front loader light and having high load capacity. The inner side of the mast is circular arc-shaped so as to lighten stress. 
     According to the frame structure for the working vehicle of the present invention, support rigidity of the radiator mount is improved so that silence of an engine room is improved. Cost is reduced, and space in the engine room is saved. 
     According to the frame structure for the working vehicle of the present invention, bolts for attachment of the rear transaxle are screwed easily so that assembly workability of the working vehicle is improved. Attachment of the rear transaxle is simplified, and excessive load to the rear transaxle and the frame of the working vehicle is suppressed by transformation of the plate body. 
     According to the frame structure for the working vehicle of the present invention, attachment of the transmission is simplified, and excessive load to the frame of the working vehicle is suppressed by transformation of the plate body. 
     According to the frame structure for the working vehicle of the present invention, the number of parts of the working vehicle is reduced so as to improve workability of assembly process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         FIG. 1  is an entire side view of a working vehicle. 
         FIG. 2  is a plan view of a frame of the working vehicle. 
         FIG. 3  is a side view of the same. 
         FIG. 4  is a front view of the same. 
         FIG. 5  is a perspective upper front view of the frame of the working vehicle. 
         FIG. 6  is a perspective lower rear view of the frame of the working vehicle. 
         FIG. 7  is a side view partially in section of connection construction of a front frame and a side frame. 
         FIG. 8  is a perspective view partially in section of a front portion of the working vehicle. 
         FIG. 9  is a perspective view of a left front portion of the frame. 
         FIG. 10  is a perspective view of a lower front portion of the frame. 
         FIG. 11  is a bottom view of the same. 
         FIG. 12  is a side view of the side frame. 
         FIG. 13  is an arrow sectional view of the line B-B in  FIG. 12 . 
         FIG. 14  is a perspective view of a rear portion of the frame. 
         FIG. 15  is a schematic drawing of attachment construction of a transmission to the frame. 
         FIG. 16  is a schematic drawing of attachment construction of a rear transaxle. 
         FIG. 17  is a perspective view of attachment construction of a tank. 
         FIG. 18  is a side view of the same. 
         FIG. 19  is a side view partially in section of internal construction of a mast section. 
         FIG. 20  is a drawing of assembly construction of a mast. 
         FIG. 21  is a drawing of reinforcement construction of bosses. 
         FIG. 22  is a perspective front view of attachment construction of a lever stand. 
         FIG. 23  is a perspective rear view of the same. 
         FIG. 24  is a drawing of attachment construction of the lever stand and a rear fender. 
         FIG. 25  is a schematic drawing of attachment construction of the lever stand. 
         FIG. 26  is a schematic drawing of assembly construction of the lever stand. 
         FIG. 27  is a front view of the lever stand. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides a light and rigid frame of a working vehicle by using a reinforcement member. 
     [Entire Construction] 
     Explanation will be given to a working vehicle that is an embodiment of the present invention. 
       FIG. 1  is an entire side view of the working vehicle. 
     The working vehicle  1  is a tractor loader backhoe and is equipped with a loader  2  and an excavator  3 . An operation part  4  is provided at the center of the working vehicle  1 . The loader  2  is disposed before the operation part  4  and the excavator  3  is disposed behind the operation part  4 . The working vehicle  1  is equipped with front wheels  8  and rear wheels  7  so as to travel while equipped with the loader  2  and the excavator  3 . 
     A steering wheel  5  and a seat  6  are disposed in the operation part  4 , and a traveling operating device and an operating device of the loader  2  are disposed at the side of the seat  6 . Accordingly, steering operation of the working vehicle  1  and the operation of the loader  2  is performed at the operation part  4 . 
     The loader  2  is connected to the working vehicle  1  and extended forward from the working vehicle  1 . A bucket is attached to the tip of the loader  2 . An engine is disposed on a front portion of a frame structure  9  which is a chassis of the working vehicle  1 , and a bonnet  30  is disposed on the frame structure  9  to cover the engine. 
     The loader  2  is disposed outside the bonnet  30 . 
     The excavator  3  is detachably attached to the rear portion of the working vehicle  1 , and the excavator  3  is operated by an operating device disposed behind the seat  6 . 
     A hydraulic oil tank  90  is disposed at the side of the operation part  4 . The hydraulic oil tank  90  also serves as a step to the operation part  4 . At the opposite side of the operation part  4 , stairs constructed by a fuel tank is provided. 
     [Frame Construction] 
     Next, explanation will be given on frame construction of the working vehicle  1 . 
       FIG. 2  is a plan view of a frame of the working vehicle. 
       FIG. 3  is a side view of the same. 
       FIG. 4  is a front view of the same. 
       FIG. 5  is a perspective upper front view of the frame of the working vehicle. 
       FIG. 6  is a perspective lower rear view of the frame of the working vehicle. 
     The frame structure  9  of the working vehicle  1  mainly comprises left and right side frames  62  extended longitudinally and adjoining laterally to each other, front frames  63  connected to the front portions of the respective side frames  62 , and a front plate  61  connecting the front portions of the front frames  63  to each other. A mast section  64  is constructed on the outer side surface of each of the front frames  63 . A rib  65  connects the front frames  63  to each other. 
     A middle partition  74  is disposed between the side frames  62  so as to connect the side frames  62  to each other, thereby making the ladder-like frame structure  9 . The middle partition  74  is a cross member partitioning an engine space between the side frames  62  and a transmission space between the side frames  62  from each other, and is disposed at the substantially longitudinal center of the frame structure  9 . 
     A beam  62   b  is extended outward from the side frames  62 . The beam  62   b  is extended laterally and substantially perpendicular to the side frames  62 . The beam  62   b  is C-like shaped when viewed in section and supports a floor part of the operation part  4 . 
     Each of the front frames  63  is extended rearward upward so as to define the lower front portion of the frame structure  9 . 
     Each of the front frames  63  is extended upward from its part connected to the corresponding side frame  62 , and the upward extended part of the front frame  63  is attached to the corresponding mast section  64 . The engine and the bonnet  30  are disposed in the engine space between the front frames  63 . A lift mechanism of the loader  2  is connected to the mast sections  64 , so that the loader  2  is supported by the mast sections  64 . 
     A mast lower section  64   b  which is a lower portion of the mast section  64  is constructed by a member projected sideward. The mast lower section  64   b  is constructed by bending a plate body and substantially laterally turned L-like shaped or laterally turned U-like shaped when viewed in side, and vertical force applied on the mast section  64  is received by the mast lower section  64   b . The mast lower section  64   b  is projected outward in the frame  9  which is the chassis of the working vehicle  1  so as to connect the bottom surface of the mast to the side surface of the frame. Namely, the mast lower section  64   b  is connected to the bottom surface of the mast section  64  and connected to the outer side surface of the front frame  63 . 
     With regard to the working vehicle  1 , the fuel tank and the hydraulic oil tank  90  are attached while hung by the mast lower section  64   b  and the beam  62   b . The fuel tank and the hydraulic oil tank  90  are respectively connected to the side portions of the mast lower section  64   b  and the beam  62   b , disposed at the same side of the working vehicle  1 , and supported. Accordingly, the support construction of the fuel tank and the hydraulic oil tank  90  is simplified so as to reduce the number of parts. When a connection part of an upper portion of a tank is similar, a tank of different capacity can be attached easily. The tank is supported by the rigid frame. The tank is attached to the bottom surface of the mast lower section  64   b  constituting the bottom portion of the mast section  64  connected to the lift mechanism of the loader  2  so that a space below the projected mast is used effectively, whereby the working vehicle  1  is constructed compactly. 
     The front plate  61  connects the front portion of the front frames  63  to each other so as to construct the front surface of the frame  9  which is the chassis of the working vehicle  1 . Holes  61   b  for tie-down are provided in the left and right lower portions of the front plate  61 . When the working vehicle  1  is conveyed, rope for fixation or the like is attached to the holes  61   b  for tie-down. The holes  61   b  are provided at the left and right of the front plate  61  so that durable holes for tie-down are constructed. The holes  61   b  for tie-down are opened longitudinally so that the rope or the like fixed to the holes are hardly twisted. The holes for tie-down are provided without welding any member to the front plate  61  so that any projection is not constructed in the front plate  61 , whereby external appearance of the front of the working vehicle  1  is improved. 
     A notch is constructed in the central upper portion of the front plate  61  so as to simplify the steps of attaching a holding mechanism of the bonnet  30 . 
     The side portions of the front plate  61  are formed along the shape of the side surfaces of the front frames  63 , and the lateral width of the front plate is tapered downward when viewed in front. 
     With regard to the frame structure of the working vehicle  1 , a seat mount base  6   b  is provided so as to connect the upper surfaces of the left and right side frame  62  to each other, whereby the seat mount base  6   b  serves as a cross member. The seat mount base  6   b  disposed laterally is connected to the upper surface of the rear portion of the frame  9 . The seat mount base  6   b  constitutes the cross member of the frame  9  so as to improve rigidity of the rear portion of the frame  9 . Accordingly, rigidity of the rear portion of the frame  9  is improved by the seat mount base  6   b  supporting the seat, whereby the number of parts is reduced. 
     [Reinforcement of Front Portion] 
     Next, explanation will be given on the construction of the frame  9  in more detail. 
       FIG. 7  is a side view partially in section of connection construction of the front frame and the side frame. 
       FIG. 8  is a perspective view partially in section of a front portion of the working vehicle. 
       FIG. 9  is a perspective view of a left front portion of the frame. 
       FIG. 10  is a perspective view of a lower front portion of the frame. 
       FIG. 11  is a bottom view of the same. 
     The frame  9  which is the chassis of the working vehicle  1  is constructed by welding flat plates and bent plates. Various portions of the frame  9  are reinforced so as to make the production of the frame of the working vehicle  1  easy and cheap. The bent plates can be constructed easily by bending so that the production cost of the working vehicle  1  is reduced and the processing is simplified compared with the case of using I-shaped steel. 
     The lower portion of the frame  9  is boat-shaped and tapered downward when viewed in front. Namely, the side surfaces of the lower portion of the frame  9  are slanted inward. By constructing the frame  9  as the above, a space in the vicinity of the front wheels  8  is secured sufficiently and the steering angle of the front wheels  8  is expanded. 
     With regard to the frame  9 , the lower portions of the side frames  62  are bent inward, and the upper and lower ends thereof are bent inward horizontally. By bending the side frames  62  inward, the effective sectional area of the side frames  62  in front view is increased so as to improve rigidity of the side frames  62 . Accordingly, interference of the front wheels and the frame  9  is prevented while improving rigidity of the side frames  62 . 
     Similarly to the side frames  62 , the lower portions of the front frames  63  are also bent inward. The inner side surfaces of the front frames  63  are connected to the outer side surfaces of the side frames  62  so as to construct the front portion of the frame  9 . The mast section  64  is connected to the upper rear portions of the front frames  63 , and attachment plates  75  and  76  disposed along lateral direction of a front transaxle are connected to the lower front portions of the front frames  63 . Plate bodies  77  are connected to the upper surface of the attachment plate  75 , and the plate bodies  77  are disposed longitudinally and parallel to each other. The side frames  62  are connected to the upper surfaces of the plate bodies  77 , the attachment plate  75  is connected to the lower surfaces thereof, and the front plate  61  is connected to the front surfaces thereof. The plate bodies  77  are disposed between the front frames  63 . 
     The attachment plate  75  is connected to the plate bodies  77  and the front frames  63 , and the plate body  76  is connected to the front plate  61  and the front frames  63 . Accordingly, durability of the lower front portion of the frame  9 , which is an attachment part of the front transaxle, is improved. The plate bodies  77  and the attachment plates  75  and  76  are combined to each other while crossing mutually in the lower front portion of the frame  9 , and then connected to the front plate  61 , the front frames  63  and the side frames  62 , whereby a box-like part is constructed. Accordingly, rigidity of the front portion of the frame  9  is improved by easy construction. 
     The attachment plates  75  and  76  to which the front transaxle is attached also serve as an oscillation stopper of the front transaxle regulating oscillation amount of the front transaxle by touching the front transaxle. Accordingly, the number of parts in the vicinity of the front transaxle is reduced. 
     The upper portion of the front frames  63  constitutes a part of the mast supporting loader  2 , and the lower portion thereof constitutes a part of a member supporting the front transaxle. Accordingly, the mast support member and the front transaxle support member are constructed integrally by the front frames  63 , whereby stress caused by applying load is dispersed so as to improve load capacity of the frame. 
     As shown in  FIG. 7 , each of the front frames  63  and the corresponding side frame  62  are combined to each other while crossing mutually. The front frame  63  and the side frame  62  are combined laterally turned T-like, and the side frame  62  is attached to the inner side of the front frame  63 . Openings  62   c  and  62   d  are provided in the side frame  62  and edges of the openings  62   c  and  62   d  are welded to the front frame  63 . Namely, the front frame  63  and the side frame  62  are plug-welded to each other while overlapping mutually. Accordingly, the front frame  63  and the side frame  62  are connected to each other easily and increase of lateral width caused by welding is prevented. 
     The connection part of the front frame  63  and the side frame  62  may also serve as a piping route. As shown in  FIG. 8 , a tailpipe  12   b  connected to a silencer  12  is extended outside the frame through an opening  63   c . As shown in  FIG. 9 , the opening  62   c  of the side frame  62  is in agreement with the opening  63   c  of the front frame  63  so as to form a hole communicating the inside of the frame with the outside thereof. The bonnet  30  is disposed on the frame  9  in the front portion of the working vehicle  1 . The bonnet  30  is formed hollowly by resin. The bonnet  30  covers the engine disposed on the frame  9 . In addition to the engine, adjunct devices of the engine such as a radiator, the muffler silencer  12  and an air cleaner  34  are also disposed in the bonnet  30 . The bonnet  30  can be opened and closed against the frame  9  and is opened by rotating upward the front portion of the bonnet  30 . Seals  33  and  32  attached to the rib  65  is disposed between the bonnet  30  and the frame  9 . A cover  36  is disposed in the front portion of the working vehicle  1  so as to cover the notch of the front plate  61 . 
     The opening  63   c  is formed in the left front frame  63  and the opening  63   c  is in agreement with the opening  62   c  of the side frame  62 . The edges of the opening  63   c  and the opening  62   c  are welded to each other so that the side frame  62  and the front frame  63  are connected to each other. The tailpipe  12   b  connected to the silencer  12  of the working vehicle  1  passes through the opening  63   c  so that exhaust of the engine is discharged outside the bonnet. The plug-welded part of the frame  9  is used for the piping so that a space for the piping is secured without affecting the frame  9 . 
     With regard to the construction of the frame  9 , the rib  65 , which is a reinforcement plate connecting the inner side surface of each of the mast sections  64  extended outside the chassis to the upper surface of the corresponding side frame  62 , is provided so as to improve rigidity of the front portion of the frame  9 . 
     The rib  65  connecting the upper portions of the mast sections  64  to each other is connected to an upper portion of a radiator mount  65   c  by a slide guide  65   b  of the bonnet  30 . One of ends of the slide guide  65   b  is fixed to the rib  65 , and the other end thereof is fixed to the radiator mount  65   c . Accordingly, support rigidity of the radiator mount  65   c  is improved so that silence in the engine room and air flow in the engine room can be controlled easily. 
     The support member of the radiator mount  65   c  also serves as the slide guide so that support rigidity of the engine room is improved while reducing cost, whereby the space in the engine room is saved. 
     [Reinforcement of Center and Rear Portions] 
     Next, explanation will be given on reinforcement construction of the frame  9  at the central portion of the vehicle. 
       FIG. 12  is a side view of the side frame. 
       FIG. 13  is an arrow sectional view of the line B-B in  FIG. 12 . 
       FIG. 14  is a perspective view of a rear portion of the frame. 
     Each of the side frames  62  is longitudinally extended and C-like shaped when viewed in front. Reinforcement members are attached to the side frames  62 . Each of the side frames  62  is provided with a pipe  66  attached to an upper portion thereof, with a rear reinforcement  68  attached to a rear portion thereof, and with a reinforcement member  67 , which is substantially triangular when viewed in side, attached to a lower rear portion thereof. Each of the side frames  62  is provided with a lower reinforcement member  69  attached to a lower surface of the longitudinal center thereof and extended along the longitudinal direction of the side frame  62 . 
     The pipe  66  attached to the upper portion of the side frame  62  is square shaped when viewed in section, and passes by the middle partition  74  disposed in the longitudinal central portion of the side frame  62  so as to extend from the engine space to the transmission space. The upper portion of the side frame  62  is bent to have a horizontal top bent portion  62   a , and the pipe  66  is attached to the inner side surface of the upper portion of the side frame  62  and is extended along the top bent portion  62   a  from the upper front end of the side frame  62  to the rear reinforcement member  68 . Accordingly, a part, to which large stress is applied, of the frame structure  9  which is the chassis of the working vehicle  1  is reinforced effectively. The square pipe used for the reinforcement can have a sufficient extent for facilitating its attachment to the side frame  62 . 
     The rear reinforcement member  68  is attached to the rear portion of each of the side frames  62 , and a rear transaxle is fixed to the rear reinforcement members  68  via later-discussed plates  68   b . An opening  62   f  is provided in a part of the side frame  62  having the rear reinforcement member  68  attached thereto so that the rear transaxle can be attached to the frame structure  9  from the outside of the side frames  62 . 
     The reinforcement member  67  is attached to the side frame  62  between the rear reinforcement member  68  and the middle partition  74 , and the reinforcement member  67  is connected at a rear end thereof to the rear reinforcement member  68 , and at a front end thereof to the middle partition  74 . The reinforcement member  67  is inversed L-like shaped when viewed in section. Each of the side frames  62  is bent at a lower portion to have a horizontal bottom bent portion  62   e . The reinforcement member  67  is connected to the bottom bent portion  62   e  and the inner side surface of the side frame  62  and the opening side of the sectional L-like shape of the reinforcement member  67  faces the side frame  62 . 
     The part of the side frame  62 , to which the reinforcement member  67  is attached, and the reinforcement member  67  defines a square structure when viewed in section. Accordingly, this part of the side frame  62  receiving reaction of driving force and load applied on a hitch is improved in rigidity, and this part, serves as a part of the frame structure  9 , to which large stress is applied, is reinforced effectively. 
     The lower reinforcement member  69  is inversely L-like shaped when viewed in front, a vertical part thereof is extended downward from a lateral inward side (the opening side of the side frame  62 ) of the bottom bent portion  62   e . The lower reinforcement member  69  is extended from the engine space to the transmission space in the frame structure  9 . A horizontal part of the lower reinforcement member  69  is attached to the lower surface of the bottom bent portion  62   e  of the side frame  62  so that the bottom part, to which large stress is applied, of the frame structure  9  which is the chassis of the working vehicle is reinforced effectively, thereby ensuring high rigidity while ensuring facility in assembling of the frame structure  9 . 
     [Attachment Construction of Transmission] 
     Next, explanation will be given on construction for attaching the transmission  10  to the frame structure  9  of the working vehicle  1 . 
       FIG. 15  is a schematic drawing of attachment construction of the transmission to the frame. 
       FIG. 16  is a schematic drawing of attachment construction of the rear transaxle. 
     Rear left and right plates  72  are fixed to outer side surfaces of the rear portions of the respective side frames  62  having the reinforcement members  67  on the inside thereof, stays  73  are extended downward from the respective plates  72 , and the transmission  10  is attached onto the stays  73  fixed to the rear portions of the side frames  62  through the rear plates  72 . The transmission  10  is fixed to rear transaxles, and the transmission  10  is fixed at a lower or side surface thereof to each of the stays  73 , which is L-like shaped when viewed in front and extended from the side frame  62 . In the embodiment shown in  FIG. 15 , each of the stays  73  is connected at a lower end thereof to the lower surface of the transmission  10 . The stay  73  is a bent plate. The stay  73  is extended downward from the outer side surface of the side frame  62  and is bent to extend to the inside of the vehicle so as to be connected to the lower surface of the transmission  10 . The stay  73  may alternatively be connected to the side surface of the transmission  10 . 
     Since the stays  73  are adapted to fix the transmission  10  to the side frames  62 , the frame structure  9  is adaptable to support any of various transmissions. The stay  73  absorbs a part of force, applied by the transmission  10 , by transforming or the like. When excessive load is applied by the transmission  10 , the stays  73  transform elastically so as to disperse the force, thereby protecting the side frames  62 , the transmission  10 , rear final transaxle casings  11  and rear transaxle casings  10   b.    
     The transmission  10  and each of the rear final transaxle casings  11  define a power train which is arch-shaped when viewed in plan as shown in  FIG. 10 . The rear final transaxle casing  11  is connected at a front portion thereof to an axle of the rear wheel  7  and is connected to a lateral distal end of the corresponding rear transaxle casing  10   b , thereby serving as an outer end part of the rear transaxle casing  10   b . The rear transaxle casing  10   b  is extended laterally, and is connected at a lateral proximal end thereof to the transmission  10 . The final rear transaxle casing  11 , the rear transaxle casing  10   b  and the transmission  10  are aligned laterally of the vehicle  1  so as to define the power train arch-shaped when viewed in plan. The rear final transaxle casing  11  incorporates a final speed change mechanism and the side frame  62  is connected to a stay  11   b  formed on the rear final transaxle casing  11  through a stay  71 . The stay  71  is fixed at an upper end thereof to the outer side surface of the side frame  62 , and at a lower end thereof fixed to the stay  11   b  formed on the rear portion of the rear final transaxle casing  11 . 
     The stay  71  supporting the rear final transaxle casing  11  functions as a spring so as to prevent excessive load from being applied on the chassis, thereby preventing the frame structure  9  of the chassis from being damaged. Excessive load in not applied on bolts so as to avoid loosening of the bolts. The stay  71  has a rigidity for supporting the rear final transaxle casing  11 , and the rigidity is changed according to variation of characteristic of a member selected as the stay  71 . The stay  71  is formed by a plate so as to reduce cost. 
     The rear transaxle casing  10   b  extended from the rear transaxle casing  11  is fixed to the rear reinforcement member  68 . The rear reinforcement member  68  is a member bent in a laterally turned U-like shape when viewed in plan, and is attached at the opened side thereof to the inner side of the side frame  62 . The rear reinforcement member  68  is extended between the top and bottom bent portions  62   a  and  62   e  of the side frame  62 . A thick plate  68   c  is attached through the top bent portion  62   a  of the side frame  62  to the upper surface of the rear reinforcement member  68 , and a thick plate  68   b  is attached to the lower surface of the rear reinforcement member  68 . An opening  62   f  is provided in the part of the side frame  62  facing the rear reinforcement member  681   s  attached thereto, and a human hand can be accessed to the thick plate  68   b  through the opening  62   f  so as to fix the thick plate  68   b  to the rear transaxle casing  10   b  by screwing bolts. The frame structure  9  of the chassis of the working vehicle  1  is constructed as the above so that the rear final transaxle casings  11  and the rear transaxle casings  10   b  can be attached to the frame structure  9  easily, allowing the working vehicle  1  to be more easily assembled. 
     [Attachment Construction of Tank] 
     Next, explanation will be given on the tanks disposed in the working vehicle  1 . 
       FIG. 17  is a perspective view of attachment construction of a tank. 
       FIG. 18  is a side view of the same. 
     The hydraulic oil tank  90  and the fuel tank  91  are disposed at the sides of the operation part  4  of the working vehicle  1 . The hydraulic oil tank  90  and the fuel tank  91  are hung at the sides of the frame  9  by members projected sideward from the frame  9 . In this embodiment, the mast lower section  64   b  and the beam  62   b  are used as the members projected sideward, and the hydraulic oil tank  90  and the fuel tank  91  are attached to the lower surface thereof. 
     The mast lower section  64   b  and the beam  62   b  are projected from the side frames  62  constituting the frame  9 . The mast lower section  64   b  is connected to the side frame  62  and the mast section  64  so as to improve rigidity of the mast section  64 . 
     Connection parts  96  having tapped holes are provided in the upper surfaces of the hydraulic oil tank  90  and the fuel tank  91 . Bolts are screwed to the connection parts of the tanks through the bottom surface of the mast lower section  64   b  and the bottom surface of the beam  62   b  so that the tanks are fastened to the bottom surface of the mast lower section  64   b  and the bottom surface of the beam  62   b . The connection parts  96  are disposed laterally in the upper surface of the hydraulic oil tank  90  and the upper surface of the fuel tank  91 , and a plurality of bolts are screwed at one connection part. The connection parts  96  are disposed laterally in the upper surfaces of the tanks so that high rigidity is secured when force is applied on the outer ends of the tanks and durability of the tanks is secured when an operator gets on or off. 
     In this embodiment, the hydraulic oil tank  90  is disposed at the right side of the frame  9  of the working vehicle  1 , and the fuel tank  91  is disposed at the left side thereof. Each of the hydraulic oil tank  90  and the fuel tank  91  is step-like (L-like) shaped when viewed in front, and the lower portion of the tank is projected more sideward (toward the outside of the vehicle) than the upper portion thereof. Accordingly, the capacity of the tank with low height is secured sufficiently and the hydraulic oil tank  90  and the fuel tank  91  are constructed compactly in the vicinity of the operation part  4 . 
     The stair surfaces of the tank can be used as a step to the operation part  4 . A non-slip member  94  is attached to each of the edges of the hydraulic oil tank  90  and the fuel tank  91  so as to secure stability at the time of getting on or off. 
     An inlet  93  of the fuel tank  91  may be projected slantingly upward outward. In this construction, the inlet  93  is provided between an upper portion  91   a  and a lower portion  91   b  of the fuel tank  91 . The inlet  93  is disposed at a portion of the outer side of the fuel tank  91  formed perpendicularly. A battery  98  is disposed on the upper surface of the fuel tank  91 . The battery  98  is disposed between the mast lower section  64   b  and the beam  62   b.    
     The hydraulic oil tank  90  and the fuel tank  91  are arranged as the above so that each of the hydraulic oil tank  90  and the fuel tank  91  can be used as a step to the operation part  4 . An operator gets on or off by treading the hydraulic oil tank  90  or the fuel tank  91  so that the change of amount of corresponding one of pressure oil and fuel is recognized by the ear according to sound of treading. The battery  98  is arranged in a blank space of the frame  9  so that a space at the side of the frame  9  is used effectively. 
     The battery  98  disposed on the fuel tank  91  is covered by a cover attached to the working vehicle  1  so as to be protected from rainwater and mud. 
     [Piping of Mast Section] 
     Next, explanation will be given on the construction of the mast sections  64 . 
       FIG. 19  is a side view partially in section of internal construction of the mast section. 
     Each of the mast sections  64  is L-like shaped when viewed in plan, and is connected to the outer side surface of the corresponding front frame  63  and to the upper surface of the mast lower section  64   b . A partition plate  64   f  is disposed between the mast section  64  and the front frame  63 . Inside the mast section  64 , a space is formed between the partition plate  64   f  and the mast section  64  so as to improve rigidity of the mast section  64 . Piping  79  is disposed in the space. 
     Bosses  80  are disposed at corresponding positions of the inner surface of the mast section  64  and the outer surface of the front frame  63  so as to support a lift device of the loader  2  at both sides. The partition plate  64   f  is attached along the bosses  80  so as to improve support rigidity of the bosses  80 . An opening  64   g  is provided in the upper portion of the partition plate  64   f  and an opening  64   h  is formed in the upper surface of the mast lower section  64   b . The piping passing through the space surrounded by the partition plate  64   f  and the mast section  64  is taken in and out through the opening  64   g  and the opening  64   g . The partition plate  64   f  is interposed in the mast structure, the piping is inserted from the lower surface and passes along the reverse side surface of the partition plate  64   f , and the opening  64   g  is provided in the front surface of the partition plate  64   f  and then the piping  79  passes through the opening. Accordingly, the piping  79  is protected and the space in the vicinity of the mast section  64  is used effectively, whereby the working vehicle is constructed compactly. 
     [Reinforcement of Mast] 
     Next, explanation will be given on the reinforcement construction of the mast. 
       FIG. 20  is a drawing of assembly construction of the mast. 
     With regard to the frame  9  of the working vehicle  1 , each of the mast comprises the mast section  64 , the partition plate  64   f , the mast lower section  64   b  and the bosses  80  and is extended to the outside of the frame  9  which is the chassis of the working vehicle  1 . 
     The mast section  64  and the partition plate  64   f  are connected to the outer surface of the corresponding front frame  63  constructed integrally with the side frame  62 . The bosses  80  of the inner side are connected to the outer side surface of the front frame  63  and the inner side of the partition plate  64   f , and the bosses  80  of the outer side are connected to the inner side surface of the mast section  64  and the outer side of the partition plate  64   f . The partition plate  64   f  is connected to the inner side surface of the mast section  64  and the side surface of the upper portion of the front frame  63  and also serves as a reinforcement plate of the mast. The upper portion of the mast lower section  64   b  is connected to the lower portions of the mast section  64  and the partition plate  64   f , and the side surface of the mast lower section  64   b  is connected to the front frame  63 . 
     The partition plate  64   f  is constructed by a thick plate so as to secure sufficient intensity and is triangle shaped when viewed in side. The partition plate  64   f  is constructed integrally with the mast section  64  so as to transmit stress of the mast section  64  to the front frame  63 , whereby load capacity of the mast is improved. 
     [Reinforcement of Boss] 
     Next, explanation will be given to the reinforcement construction of the bosses  80 . 
       FIG. 21  is a drawing of reinforcement construction of the bosses.  FIG. 21(   a ) is a perspective view of reinforcement construction of the bosses, and  FIG. 21(   b ) is a front view of reinforcement construction of the bosses. 
     Each of the bosses  80  is gently-sloping chevron-like shaped, and the left and right bosses  80  are connected to each other through the foots thereof by a reinforcement member  81 . The reinforcement member  81  is connected to the lower portions of the bosses  80  and is substantially U-like shaped. The bosses  80  are connected to the reinforcement member  81  by welding so that the bosses  80  and the reinforcement member  91  are constructed integrally with each other. The bosses  80  may alternatively be formed integrally with the reinforcement member  81  previously. 
     The reinforcement member  81  is attached to the front surface of the partition plate  64   f  of the mast section  64  and is connected to the left and right bosses  80 . The reinforcement member  81  may be connected to the upper and lower bosses  80  in addition to the left and right bosses  80 . 
     The reinforcement member  81  is connected to the bosses  80  as the above so that the bosses  80  and the mast section  64  are reinforced easily. 
     [Attachment Construction of Lever Stand] 
     Next, explanation will be given on a lever stand  85  disposed to the working vehicle  1 . 
       FIG. 22  is a perspective front view of attachment construction of the lever stand. 
       FIG. 23  is a perspective rear view of the same. 
       FIG. 24  is a drawing of attachment construction of the lever stand and a rear fender. 
       FIG. 25  is a schematic drawing of attachment construction of the lever stand. 
       FIG. 26  is a schematic drawing of assembly construction of the lever stand. 
       FIG. 27  is a front view of the lever stand. 
     The lever stand  85  is attached to the frame  9  of the working vehicle and is disposed in the operation part  4 . Operation levers operating the front loader  2  and the like are disposed in the lever stand  85 , and the levers are connected to a hydraulic valve unit  85   b  attached to the lever stand  85 . The hydraulic valve unit  85   b  is attached to the lever stand  85  so as to be constructed integrally with the lever stand  85 . The lever stand  85  is attached to the frame  9  and then hydraulic piping is connected to the hydraulic valve unit  85   b  so that hydraulic apparatuses are operated by the levers. 
     An electronic part assembly  85   c  of a meter and the like is attached to a part extended rearward from the lever disposition part of the lever stand  85 . The hydraulic operation levers, the hydraulic valve unit  85   b  and the electronic part assembly  85   c  are constructed integrally with the lever stand  85 . 
     Accordingly, members which must be treated carefully are arranged intensively in the lever stand  85  so as to improve workability of assembly process of the working vehicle  1 , whereby management of parts is simplified. 
     The electronic part assembly  85   c  is disposed on the surface, at the inner side of the vehicle, of the rearward extended part of the lever stand  85 . 
     In the lever stand  85 , the piping connection part of the hydraulic valve unit  85   b  and the electronic part assembly  85   c  are disposed at the inner side of the vehicle so that maintenance work of the hydraulic valve unit  85   b  and the electronic part assembly  85   c  is simplified, and wiring and piping work at the time of attaching is simplified. 
     The lower front portion of the lever stand  85  is connected to the upper surface of the beam  62   b  extended outward from the side frame  62 , and the lower center portion and the lower rear portion of the lever stand  85  are connected to the upper surface of the side frame  62 . A stay  62   r  extended upward rearward from the upper portion of the side frame  62  is connected to the vicinity of the disposition part of the electronic part assembly  85   c  so as to support the central portion of the lever stand  85 . 
     Rear fenders  86  covering the rear wheels  7  is attached to the vicinity of the lever stand  85 . Each of the rear fenders  86  is connected to the rear surface of the beam  62   b  and the rear portion of the lever stand  85  so as to be supported. A connection part  86   b  is provided in the lower front portion of the rear fender  86  and is fixed to the rear surface of the beam  62   b  by fastening. A stay  86   c  is provided in the upper portion of the rear fender  86  and is connected through a connection member  100  to the rear extended part of the lever stand  85  so as to absorb the gap of connection to a plurality of members in consideration of assemble ability. The stay  86   c  is extended upward from the upper surface of the rear fender  86 . The lower portion of the connection member  100  is connected to the stay  86   c  and the connection member  100  is extended from the rear fender  86  toward the inner side of the working vehicle. The part of the connection member  100  extended toward the inner side of the vehicle is connected to the rear portion of the lever stand  85 . 
     The front end of the fender  86  is fixed to the beam  62   b  and the central portion or the rear portion of the fender  86  is fixed to the frame  62  through the lever stand  85 . The lever stand  85  also serves as a stay of the fender  86  so as to simplify the construction in the vicinity of the rear wheels  7  of the working vehicle  1 . 
     Rigidity of the rear fender  86  which is a member made by a thin metal sheet is improved. 
     Namely, the lever stand  85  also serves as a support member of the fender  86  so as to reduce number of component parts of the working vehicle  1 . The number of stays attached to the frame  9  of the working vehicle  1  is reduced so that labor of the production process is reduced, whereby the production cost is reduced.