Abstract:
A riding type mower comprises: a plurality of wheels; a vehicle body supported by the plurality of wheels; a water-cooled engine located in a rear region of the vehicle body; a hood for covering the engine; a driver&#39;s seat located forwardly of the hood; a rollover protection frame located between the driver&#39;s seat and the water-cooled engine, the rollover protection frame having a pair of right and left support columns spaced apart from each other in a lateral direction; a radiator for the water-cooled engine located between the pair of the support columns of the rollover protection frame.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a riding type mower having a rollover protection frame. 
     A known riding type mower of the type noted above includes a motor section disposed at the rear of a vehicle body having front wheels and rear wheels, a driver&#39;s seat mounted forwardly of the motor section, and an arch-shaped rollover protection frame erected rearwardly of the driver&#39;s seat (see Japanese Unexamined Patent Publication No. 2004-237953, for example). 
     In the above conventional riding type mower, an air-cooled gasoline engine is mounted in the motor section to make the motor section short in the fore and aft direction, thereby to make the vehicle body compact over the entire length thereof. However, a high-power water-cooled engine is desired in order to improve running capability and grass cutting capability. 
     With the water-cooled engine, generally, a radiator cooled by a cooling fan driven by engine power is disposed in front of the engine. Consequently, the motor section accommodating the radiator and engine tends to be long in the fore and aft direction, thereby impairing compactness over the entire length of the vehicle body. 
     A riding type mower in accordance with the present invention comprises: a plurality of wheels; a vehicle body supported by the plurality of wheels; a water-cooled engine located in a rear region of the vehicle body; a hood for covering the engine; a driver&#39;s seat located forwardly of the hood; a rollover protection frame located between the driver&#39;s seat and the water-cooled engine, the rollover protection frame having a pair of right and left support columns spaced apart from each other in a lateral direction; a radiator for the water-cooled engine located between the pair of the support columns of the rollover protection frame. 
     Since the radiator is located between the support columns of the rollover protection frame, the space between the support columns can be utilized efficiently. 
     SUMMARY OF THE INVENTION 
     This invention has been made having regard to the state of the art noted above, and its primary object is to provide a riding type mower of high capabilities that can carry a water-cooled engine and that makes efficient use of its space. 
     A riding type mower comprises: a plurality of wheels; a vehicle body supported by the plurality of wheels; a water-cooled engine located in a rear region of the vehicle body; a hood for covering the engine; a driver&#39;s seat located forwardly of the hood; a rollover protection frame located between the driver&#39;s seat and the water-cooled engine, the rollover protection frame having a pair of right and left support columns spaced apart from each other in a lateral direction; a radiator for the water-cooled engine located between the pair of the support columns of the rollover protection frame. 
     Since the radiator is located between the support columns of the rollover protection frame, the space between the columns are utilized efficiently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation of a riding type mower; 
         FIG. 2  is a plan view of the riding type mower; 
         FIG. 3  is a side view of a rear portion of a vehicle body; 
         FIG. 4  is a rear view of the vehicle body; 
         FIG. 5  is a side view of the rear portion of the vehicle body with a hood and an upper cover opened; 
         FIG. 6  is a side view showing a body frame and a rollover protection frame; 
         FIG. 7  is an exploded perspective view showing the body frame and rollover protection frame; 
         FIG. 8  is a perspective view showing a radiator support structure; 
         FIG. 9A and 9B  are side views showing a seal structure around the radiator; 
         FIG. 10  is a plan view showing the seal structure around the radiator; 
         FIG. 11  is a perspective view showing a lock structure of the upper cover and hood; and 
         FIG. 12  is a sectional view showing an exhaust structure of a muffler. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a side elevation of a riding type mower according to this invention.  FIG. 2  shows a plan view of the grass mower. This riding type mower is what is called a mid-mount mower with a bar blade type mower unit  4  suspended from a vehicle body  1  between a pair of right and left front wheels  2  and a pair of right and left rear wheels  3 . The vehicle body  1  has a motor section  6  mounted on a rear portion thereof and housing an engine  5 , and a driver&#39;s seat  7  disposed in an intermediate position in the fore and aft direction of the vehicle body  1 . 
     The right and left front wheels  2  are in the form of caster type idle wheels. The right and left rear wheels  3  are drive wheels subjected to stepless speed changing and reversibly driven independently of each other. The mower can travel straight forward or backward by driving the right and left rear wheels  3  at equal speed forward or backward, and can turn to a selected direction by driving the right and left rear wheels  3  at different speeds. 
     As shown in  FIGS. 6 and 7 , a body frame  8  of the vehicle body  1  includes a forward frame unit  8 F of large transverse dimensions and a rearward frame unit  8 R of small transverse dimensions. The forward frame unit  8 F includes a pair of right and left frame strips  8   a  opposed to each other with a large transverse space in between, a front cross frame  8   b  extending and connected between front ends of the right and left frame strips  8   a , and a rear cross frame  8   c  extending and connected between rear ends of the right and left frame strips  8   a . The rearward frame unit  8 R includes a pair of right and left vertical frame plates  8   d  connected to the rear cross frame  8   c  and opposed to each other with a smaller transverse space in between than in the forward frame unit  8 F, and a cross support shaft  8   e  connecting intermediate positions in the fore and aft direction of the right and left frame plates  8   d , and a cross frame plate  8   f  connecting rear ends of the right and left frame plates  8   d.    
     Front links  11  and rear links  12  are connected to front and rear positions of the forward frame unit  8 F to be vertically pivotable about axes a and b, respectively. The mower unit  4  is connected to free ends of these front links  11  and rear links  12  to be supported and suspended in a parallelogram linkage mode. A control arm  12   b  is rigidly connected to, and extends from, a pivot shaft  12   a  interconnecting the rear links  12 . A single-acting hydraulic cylinder  13  extends between the control arm  12   b  and the cross support shaft  8   e  of the rearward frame unit  8 R. The hydraulic cylinder  13  is extended by pressure oil supply to rock the rear links  12  upward to raise the mower unit  4  in parallel. The hydraulic cylinder  13  is contracted by oil drain therefrom, whereby the mower unit  4  lowers in parallel by gravity. 
     Vertical frames  8   g  project upward from adjacent the rear ends of the forward frame unit  8 F, and define the pivotal axis b of the rear links  12 . An upper cover  14  is pivotally connected to the vertical frames  8   g  to be vertically pivotable about an axis c. The driver&#39;s seat  7  is supported by the upper cover  14  to be positionally adjustable forward and backward. 
     Mounting brackets  15  and  16  project from right and left inner surfaces in rearward positions of the frame plates  8   d  and from right and left inner surfaces of the cross frame plate  8   f  of the rearward frame unit  8 R, respectively. The engine  5  is mounted on these front and rear, right and left mounting brackets  15  and  16  in a vibration isolating manner. 
     The engine  5  used here is a water-cooled diesel engine with a radiator  18  disposed in front thereof, and an output shaft extending in the fore and aft direction. The engine  5  and radiator  18  are covered by a hood  19  attached, to be pivotable open and close about an axis d, to upper ends of stays  20  erected from the cross frame plate  8   f . A cooling fan  21  rotatable by engine power is disposed behind the radiator  18  for drawing ambient air through an air inlet of dustproof structure formed in a front end of the hood  19  and supplying the air to the radiator  18 . 
     As shown in  FIGS. 8-10 , a partition plate  22  is disposed around the radiator  18  for preventing the heat in the engine room from diffusing forward around the radiator. The radiator  18  has a hollow sealer (trim)  23  attached peripherally thereof for elastically adhering to the hood  19 . The sealer  23  includes an upper seal  23   a  extending along the outside of an upper edge of the partition plate  22 , and side seals  23   b  extending along the backs of right and left edges of the partition plate  22 . When the hood  19  is in a closed state, the upper seal  23   a  is in direct pressure contact with an inner surface of a top plate portion of the hood  19 , while the side seals  23   b  are pressed at the rear thereof by presser pieces  19   a  projecting from right and left inner surfaces of the hood  19 . This construction prevents the sealer  23  from detaching from the partition plate  22  by being rubbed by the right and left inner surfaces of the hood  19  being closed from an open state. 
     As shown in  FIG. 12 , a bent exhaust pipe  25  extends from a muffler  24  mounted in the engine room, and projects from the rear end of the hood  19  outside the vehicle body. The exhaust pipe  25  is fitted with a small gap “s” to a tube  24   a  projecting from the muffler  24 . Hot exhaust gas is diluted with ambient air drawn in through the small gap “s” by ejector action. The exhaust pipe  25  also has a cutout k downstream of a bend thereof. Exhaust gas is diluted with ambient air drawn in through the cutout k by ejector action accompanying the flow of the exhaust gas, to further lower the gas temperature. 
     A rear-wheel drive unit  30  is connected to, and supported by, intermediate positions in the fore and aft direction of the right and left frame plates  8   d  of the rearward frame unit  8 R. As shown in  FIGS. 3 and 4 , the rear-wheel drive unit  30  includes a central transmission case  31  that receives output from the engine  5 , a pair of hydrostatic stepless transmissions (HSTs)  32  connected to right and left sides of the transmission case  31 , and a pair of right and left reduction cases  33  supporting the rear wheels  2 . Engine power inputted to the central transmission case  31  from the back is branched right and left and transmitted to the hydrostatic stepless transmissions  32 . Outputs at varied speeds from the hydrostatic stepless transmissions  32  are subjected to gear reduction in the reduction cases  33  and transmitted to axles  34  of the rear wheels  2 . Further, a PTO shaft  35  projects from the front of the central transmission case  31 . Working power taken from the PTO shaft  35  is transmitted through shafts to the mower unit  4 . 
     The hydrostatic stepless transmissions  32  are the well-known axial plunger type each having a built-in fixed displacement motor (not shown) steplessly reversible by changing the swash plate angle of a built-in variable displacement pump (not shown) to vary discharge oil quantity and discharge direction. A swash plate angle control unit of each hydrostatic stepless transmission  32  is linked to one of shift levers  36  arranged at right and left sides of the driver&#39;s seat  7  to be rockable fore and aft. Each hydrostatic stepless transmission  32  is in a neutral, stop position when the shift lever  36  is held in a fore and aft neutral position, in a position to provide forward speeds when the shift lever  36  is operated forward from the neutral position, and in a position to provide backward speeds when the shift lever  36  is operated backward from the neutral position. 
     The forward frame unit  8 F of the body frame  8  supports a footrest  37  located in a foot area of the driver&#39;s seat  7 . Fenders  38  are arranged at the right and left sides of the driver&#39;s seat  7 . A fuel tank  39  is disposed below each fender  38 . 
     Each of the right and left reduction cases  33  has a brake  40  of the multi-plate type. Each brake  40  is linked to a brake pedal  41  disposed adjacent the center at the front of the footrest  27 . The right and left brakes  40  are simultaneously operated by depressing the brake pedal  41 . A brake lock pedal  42  for parking is disposed at a side of the brake pedal  41  for retaining the brake pedal  41  in a depressed position. Each of the right and left brakes  40  is operable independently of the other also by laterally outwardly rocking the right or left shift lever  36 . This feature may be used when making a pivot turn by stopping one rear wheel  2  and driving only the other. 
     An arch-shaped rollover protection frame  45  is fixedly and substantially vertically erected rearwardly of the driver&#39;s seat  7 . The rollover protection frame  45  is collapsible by folding it backward about an axis e at a vertically intermediate level. By folding up the rollover protection frame  45  in time of a mowing operation around trees, the mower can engage in the operation without the protection frame  45  getting caught by branches spreading out. 
     The rollover protection frame  45  has right and left support columns  45   a  bolt-connected at lower ends thereof to the right and left frame plates  8   d  of the rearward frame unit  8 R. The support columns  45   a  of the rollover protection frame  45  as a whole converge downward, with portions above vertically intermediate positions curved laterally outward. Vertical connecting pieces  46  are attached to curved portions of the right and left support columns  45   a . Vertical frames  8   g  project upward from the frame strips  8   a  of the forward frame unit  8 F. Auxiliary frames  47  are provided to extend between the vertical frames  8   g  and the vertical connecting pieces  46  of the rollover protection frame  45 . 
     The auxiliary frames  47  are interconnected in two, fore and aft positions thereof by cross frames  47   a  to form a highly rigid open framework. With the forward frame unit  8 F of the body frame  8  and the rollover protection frame  45  interconnected by the auxiliary frames  47  in the form of a square framework, the entire body frame  8  has increased rigidity against vertical bending and twisting forces. 
     Sideways connecting pieces  48  (radiator support member) are attached to the curved portions of the right and left support columns  45   a  of the rollover protection frame  45 . The sideways connecting pieces  48  define mounting bores  49  to which the bottom of the radiator  18  is connected for support through rubber cushions  50 . The radiator  18  is erected as slightly tilted rearward. Seen laterally of the vehicle body, the radiator  18  is in an overlapping arrangement with the right and left support columns  45   a  of the rollover protection frame  45 , the radiator  18  being fitted between the support columns  45   a . The mounting bore  49  formed in each sideways connecting piece  48  is in the form of united right and left twin bores to be capable of connecting and supporting radiators  18  of different widths. 
     The auxiliary frames  47  have a lock mechanism  51  for locking the upper cover  14  and hood  19  to a closed position. As shown in  FIGS. 3 ,  5 , and  11 , the auxiliary frames  47  have a lock member  53  attached thereto to be pivotable fore and aft about an axis f and biased forward by a spring  52 . The lock member  53  includes right and left hooks  53   a  for engaging right and left lock bores  54  formed in the upper cover  14 , to lock the upper cover  14  to the closed position. The lock member  53  has a lock detent  56  connected thereto to be pivotable fore and aft about an axis g. The lock detent  56  is engageable from front with an engaging piece  57  disposed at a lower front end of the hood  19 , to lock the hood  19  to the closed position. 
     The right and left hooks  53   a  of the lock member  53  project to a large extent from the lock bores  54  of the upper cover  14 . By manually moving any one of the hooks  53   a  rearwardly, the hood  19  and upper cover  14  can be successively unlocked. When the hooks  53   a  in the locking position are moved rearwardly within a range not disengaging from the lock bores  54 , the lock detent  56  moves forward with a pivotal movement of the lock member  53 , to disengage from the engaging piece  57 , thereby unlocking the hood  19 . The upper cover  14  can be unlocked by further moving the hooks  53   a  to the extent of disengaging from the lock bores  54 .