Abstract:
A working vehicle having a propelling transmission for transmitting power of an engine to drive wheels, the propelling transmission being attached to body frames as offset to one side transversely of a vehicle body to produce a utility space in the other side, with a PTO apparatus for transmitting power supplied from the propelling transmission to an external working implement. The PTO apparatus ( 40 ) includes an input shaft ( 42 ) extending longitudinally of the vehicle body and drivably connected to the propelling transmission, and an output shaft ( 43 ) extending parallel to and spaced from the input shaft and drivingly connected to the external working implement. A mounting mechanism ( 30; 50 ) is provided to attach the PTO apparatus to vehicle body frames ( 8 ). The mounting mechanism selectively fixes the PTO apparatus to at least two pivotal postures about the input shaft.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a working vehicle having a propelling transmission for transmitting power of an engine to drive wheels, the propelling transmission being attached to body frames as offset to one side transversely of a vehicle body to produce a utility space in the other side, with a PTO apparatus for transmitting power supplied from the propelling transmission to an external working implement.  
           [0003]    2. Description of the Related Art  
           [0004]    The above working vehicle, when an external working implement such as a rotary plow is connected to the rear of the vehicle body, transmits power supplied from the propelling transmission to the external working implement through the PTO apparatus.  
           [0005]    A tractor which is a typical example of working vehicle may be used as a cultivating machine with a rotary plow connected to the rear of a tractor body. Alternatively, the tractor may be used as a grass cutting machine or a dust collecting machine with a mower unit or a dust collector connected to the vehicle body between front and rear wheels, and a grass catcher or a dust catcher attached to the rear of the vehicle body. A receiving portion of the grass catcher or dust catcher is connected to a discharge portion of the mower unit or dust collector through a transmitting duct. A blower is driven to transmit grass clippings or dust to the grass catcher or dust catcher.  
           [0006]    When the tractor is constructed to act as a cultivating machine, a power transmission line from the propelling transmission through the PTO apparatus to the rotary plow tends to bend to a great extent three-dimensionally with the rotary plow moving up and down. As a result, transmission noise tends to be generated from connections in the power transmission line.  
           [0007]    When the tractor is constructed to act as a grass cutting machine or dust collecting machine, the transmitting duct usually extends from the mower unit or dust collector outwardly of the tractor body from between the front and rear wheels and to the grass catcher or dust catcher. Thus, the transmitting duct provides an elongated transmission path with many bends. This results in grass or dust transmitting difficulties and enlarged transverse dimensions of the tractor body to encumber driving.  
         SUMMARY OF THE INVENTION  
         [0008]    The object of this invention is to provide a working vehicle free from inconveniences in power transmission or grass or dust transmission when converted to a cultivating machine with an external working implement such as a plowing implement attached, or when converted to a grass cutting or dust collecting machine with an external working implement such as a mower unit or dust collector attached.  
           [0009]    The above object is fulfilled, according to this invention, by a working vehicle having a propelling transmission as set forth at the outset hereof, comprising a PTO apparatus for transmitting power supplied from the propelling transmission to an external working implement, the PTO apparatus includes an input shaft extending longitudinally of the vehicle body and drivably connected to the propelling transmission, and an output shaft extending parallel to and spaced from the input shaft and drivingly connected to the external working implement; and a mounting mechanism for attaching the PTO apparatus to vehicle body frames, the mounting mechanism selectively fixing the PTO apparatus to at least two pivotal postures about the input shaft.  
           [0010]    With this construction, an optimal position may be selected for the output shaft of the PTO apparatus according to an external working implement to be attached. Moreover, since the position of the input shaft is unchanged, a construction is employed to turn the PTO apparatus about the input shaft, which realizes a simplified mounting mechanism.  
           [0011]    In a preferred embodiment of this invention, the mounting mechanism includes a support platform for detachably attaching the PTO apparatus, and a mounting base connected to the support platform and detachably attached to the vehicle body frames. The PTO apparatus may be fixed reliably by using a support platform suitable to each different pivotal posture of the PTO apparatus. As a particularly preferred embodiment, the support platform may include a first support plate for supporting the PTO apparatus with the output shaft offset to the one side transversely of the vehicle body, and a second support plate for supporting the PTO apparatus with the output shaft in a substantially middle position transversely of the vehicle body. This construction provides two typical positions of the output shaft in a simple way.  
           [0012]    In another preferred embodiment of this invention, when the PTO apparatus is attached to the vehicle body frames by using the first support plate, the PTO apparatus as a whole is disposed in the side to which the propelling transmission is offset, a dust transmitting duct extending longitudinally of the vehicle body through the utility space. In this construction, the PTO apparatus is offset to the same side to which the propelling transmission is offset, to produce a sufficient space between one of the right and left rear wheels and the power takeoff apparatus to accommodate the dust transmitting duct. Thus, when the working vehicle is converted to a grass cutting machine or a dust collecting machine, the transmitting duct extending between the right and left rear wheels can quickly and efficiently transmit grass clippings or dust to a grass catcher or a dust catcher. The machine is easy to drive since the overall transverse dimensions are not increased.  
           [0013]    In a further preferred embodiment of this invention, when the PTO apparatus is attached to the vehicle body frames by using the second support plate, a power transmission line extends substantially linearly with respect to a transverse direction of the vehicle body, from the output shaft of the PTO apparatus to a plowing implement acting as the external working implement. With this construction, considering that the plowing implement apparatus usually has a power input portion thereof located in the middle position, no great three-dimensional bending occurs with the power transmission line from the output shaft of the PTO apparatus to the plowing implement. Consequently, when the working vehicle is converted to a cultivating machine, connections in the power transmission line are bent to a less degree, thereby hardly producing transmission noise, even when the plowing implement moves up and down.  
           [0014]    Other features and advantages of this invention will be apparent from the following description of the embodiment to be taken with reference to the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a side elevation of a riding lawn mower;  
         [0016]    [0016]FIG. 2 is a plan view of a rear portion of the lawn mower;  
         [0017]    [0017]FIG. 3 is a rear view of the lawn mower;  
         [0018]    [0018]FIG. 4 is a side view of a power takeoff portion of the lawn mower;  
         [0019]    [0019]FIG. 5 is a rear view of the power takeoff portion;  
         [0020]    [0020]FIG. 6 is a perspective view of a mounting member and a grass catcher of the lawn mower;  
         [0021]    [0021]FIG. 7 is a side view in vertical section of a power takeoff apparatus;  
         [0022]    [0022]FIG. 8 is a side elevation of a riding cultivating machine;  
         [0023]    [0023]FIG. 9 is a plan view of a power takeoff portion of the cultivating machine;  
         [0024]    [0024]FIG. 10 is a side view of the power takeoff portion of the cultivating machine;  
         [0025]    [0025]FIG. 11 is a rear view of the power takeoff portion of the cultivating machine; and  
         [0026]    [0026]FIG. 12 is a perspective view of a mounting member of the cultivating machine. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]    As shown in FIG. 1, a riding tractor, which is one example of working vehicle, includes a pair of right and left, freely rotatable and dirigible front wheels  1  and a pair of right and left rear drive wheels  2  supporting a vehicle body. A motor section having an engine  3  is disposed on a front portion of the vehicle body. Rearwardly of the motor section is a driving platform including a steering wheel  4  for steering the front wheels  1 , and a driver&#39;s seat  5 .  
         [0028]    This tractor may be converted to a riding grass cutting machine as shown in FIG. 1 and a riding rotary cultivating machine as shown in FIG. 8.  
         [0029]    As shown in FIGS. 1, 2 and  3 , the engine  3  is disposed between the right and left front wheels  1 , and a propelling transmission  7  is disposed between the right and left rear wheel  2 . Both the engine  3  and propelling transmission  7  are disposed between a pair of right and left body frames  8  and supported by the body frames  8 . The propelling transmission  7  is offset toward one of the rear wheels  2 . An output shaft at the rear end of engine  3  is connected to an input shaft  7   a  of propelling transmission  7  through a rotary transmission shaft  6 .  
         [0030]    The propelling transmission  7  includes a hydraulic stepless transmission  7   b  having a hydraulic pump driven by the input shaft  7   a  and a hydraulic motor driven by the hydraulic pump. The propelling transmission  7  transmits torque output of stepless transmission  7   b  through right and left output shafts  7   d  of a rear differential mechanism  7   c  to gear transmission mechanisms in rear wheel drive cases  9 . The gear transmission mechanisms transmit the power to rear axles  2   a  disposed above. That is, the stepless transmission  7   b  switches torque received from the engine  3  to forward drive or backward drive, and steplessly changes the speed of forward drive or backward drive. The drive is then transmitted through the output shafts  7   d  of rear differential mechanism  7   c  to the right and left rear axles  2   a  to drive the right and left rear wheels  2 .  
         [0031]    A power supply shaft  7   e  projects rearward from a casing of stepless transmission  7   b  of input shaft  7   a  to act as a power supply portion to drive an external working implement.  
         [0032]    The tractor converted to a grass cutting machine is shown in FIGS. 1 through 7. As shown in FIGS. 1, 2 and so on, a mower unit  15  is vertically movably connected to the vehicle body between the front and rear wheels through a link mechanism including front pivot links  11  having forward ends thereof pivotally connected to support elements arranged at front end positions of the vehicle body, and rear pivot links  13  having forward ends thereof pivotally connected to link brackets  12  fixed to right and left body frames  8  between the front and rear wheels. Torque of an output shaft at the front of engine  3  is transmitted to an input case  15   b  on the upper surface of a mower deck  15   a  of mower unit  15  through a belt type transmission mechanism  16  and a rotary shaft  17 .  
         [0033]    As shown in FIGS. 1, 2 and so on, a lift arm  20  is connected to the rear end of left pivot link  13  through a suspender rod  19 , and a lift arm  20  is connected to the rear end of right pivot link  13  through a suspender rod  19 . The lift arms  20  are interconnected by a rotatable lift arm support shaft  21  extending between the right and left body frames  8 . To this lift arm support shaft  21  is connected, through a swing arm, a piston of a lift cylinder  22  having a tube end supported by one of the body frames  8 . The lift cylinder  22  rotates the lift arm support shaft  21  to swing the right and left lift arms  20  up and down. The right and left rear pivot links  13  are thereby swung up and down relative to the body frames  8  to raise or lower the mower unit  15 .  
         [0034]    As shown in FIGS. 2 through 6, a grass catcher  25  is attached to the rear of the vehicle body, and a lifting device  26  is provided which has an upper end thereof connected to a receiving portion of grass catcher  25 , and a lower end having a collecting blower  27 . The collecting blower  27  is connected through a transmitting duct  28  to a grass discharge portion of mower deck  15   a  of mower unit  15 . Power is transmitted from the power supply shaft  7   e  of propelling transmission  7  to the collecting blower  27 . The mower unit  15  cuts grass with a plurality of cutting blades  15   c  rotating in the mower deck  15   a  and feeds grass clippings into the transmitting duct  28  along with air flows generated by the rotation of cutting blades  15   c . The grass clippings move through the transmitting duct  28  and lifting device  26  to the grass catcher  25  to accumulate in the grass catcher  25 .  
         [0035]    As shown in FIGS. 5, 6 and so on, a first mounting mechanism (mounting mechanism for the grass cutting machine)  30  includes an outer frame  31  formed of sheet metal members combined into a rectangular shape, seen in the fore and aft direction of the vehicle body, a vertical frame member  32  disposed inside the outer frame  31  and interconnecting middle positions of an upper frame portion and a lower frame portion of outer frame  31 , and a support plate  33  acting as a support platform formed of a sheet metal member extending between the vertical frame member  32  and a side frame portion of outer frame  31 . The outer frame  31  has opposite side plates acting as mounting bases  34  for connecting the first mounting mechanism  30  to the body frames  8 . Both right and left mounting bases  34  are detachably connected to the body frames  8  by connecting bolts  36  attached to the outer frame  31  and body frames  8  through a plurality of bolt holes  35  formed in the mounting bases  34 .  
         [0036]    That is, when converting the tractor to the grass cutting machine, as shown in FIGS. 1, 2,  4 , and  6 , the first mounting mechanism  30  is detachably attached, through the mounting bases  34  at the opposite sides of outer frame  31 , to inward surfaces adjacent the rear ends of right and left body frames  8 . The grass catcher  25  is supported by the vehicle body, with right and left support rods  25   a  of grass catcher  25  connected to the outer frame  31  of first mounting mechanism  30 . The lower end portion of lifting device  26  is supported by the vehicle body, with support rods  27   a  extending from a blower case of lifting device  26  being connected to the outer frame  31  and vertical frame member  32  of first mounting mechanism  30 .  
         [0037]    As shown in FIGS. 2, 4 and  5 , a power takeoff (PTO) apparatus  40  includes an input shaft  42  projecting from one end of a power takeoff (PTO) case  41 , and a tubular power takeoff (PTO) shaft  43  projecting in the opposite direction from the other end. The power takeoff apparatus  40  is detachably fixed to the support plate  33  by fastening the power takeoff case  41  of power takeoff apparatus  40  to the support plate  33  with a plurality of mounting bolts  44  acting also to fastening a front surface and a rear surface of power takeoff case  41  together. As a result, a power transmission line from the power supply shaft  7   e  of propelling transmission  7  extends to the collecting blower  27  while being offset to one side transversely of the vehicle body between the right and left rear wheels  2 . A space  28 S is formed in the other side transversely of the vehicle body between the right and left rear wheels  2  for accommodating the transmitting duct  28 .  
         [0038]    As shown in FIG. 7, the power takeoff apparatus  40  includes the power takeoff case  41  having the input shaft  42  and power takeoff shaft  43 , and a transmission control mechanism  45  disposed in the power takeoff case  41  for interlocking the input shaft  42  to the power takeoff shaft  43 . The transmission control mechanism  45  includes a hydraulically operable clutch mechanism  48  switchable between an engaged position and a disengaged position by a clutch lever  46  pivotably attached to a rear of the portion of power takeoff case  41  having the input shaft  42  to switch a valve  47 , and a gear transmission mechanism  49  having a plurality of transmission gears for decelerating torque of an output shaft  48   a  of clutch mechanism  48  for transmission to the power takeoff shaft  43 .  
         [0039]    When the power takeoff apparatus  40  is supported by the support plate  33 , the entire power takeoff apparatus  40  is offset transversely of the vehicle body toward where the propelling transmission  7  is disposed, by the positioning action of first mounting mechanism  30 . A utility space  28 S is formed between the power takeoff apparatus  40  and one of the rear wheels  2  to accommodate the transmitting duct  28 . Consequently, the transmitting duct  28  may be disposed to extend through the space  28 S between the right and left rear wheels  2  to connect the mowing device  15  and lifting device  26 .  
         [0040]    As seen from FIG. 2, when the power takeoff apparatus  40  is supported by the support platform (i.e. support plate)  33 , the input shaft  42  of power takeoff apparatus  40  projects forward from the power takeoff case  41  to be placed rearwardly of and coaxial with the power supply shaft  7   e  of propelling transmission  7  by the positioning action of the first mounting mechanism  30 . The power supply portion  7   e  and input shaft  42  are connected to each other to be separable and rotatable together by a coupling  42   a . This coupling has a forward end thereof fitted on the power supply shaft  7   e  to be separable and rotatable together through a spline engagement, and a rear end fitted on the input shaft  42  to be separable and rotatable together through a spline engagement. The power takeoff shaft  43  is disposed rearwardly of the propelling transmission  7  and offset to one side from the middle position transversely of the vehicle body, and projects rearward from the power takeoff case  41 . As a result, as shown in FIG. 4, the rear end of a rotary transmission shaft  38  rotatably supported by a boss  37   a  of a support  37  extending from the outer frame  31  of first mounting mechanism  30  and having a forward end connected to the power takeoff shaft  43  through a spline engagement to be rotatable together is drivingly interlocked by a transmission belt  39  to a blower drive shaft  27   b  projecting rearward from the blower case of collecting blower  27 . The power of power supply shaft  7   e  of propelling transmission  7  is transmitted by the power takeoff apparatus  40  laterally of the transmitting duct  28  rearwardly of the vehicle body, and transmitted from the power takeoff shaft  43  of power takeoff apparatus  40  to the blower drive shaft  27   b  to drive the collecting blower  27 .  
         [0041]    [0041]FIG. 8 shows the tractor converted to a cultivating machine. In the cultivating machine, as shown in FIGS. 9 through 12, a second mounting mechanism  50  includes an outer frame  51  formed of sheet metal members combined into a rectangular shape, seen in the fore and aft direction of the vehicle body, a vertical frame member  52  disposed inside the outer frame  51  and interconnecting end positions of an upper frame portion and a lower frame portion, and a second support plate  53  acting as a support platform formed of a sheet metal member extending between the vertical frame member  52  and a side frame portion of outer frame  51 . The second mounting mechanism  50  has a top link bracket  54  attached to an middle inward surface of the upper frame portion of outer frame  51 , and a lift arm support shaft  55  rotatably supported by upper ends of right and left side frame portions of outer frame  51 . Proximal ends of lift arms  56  are rigidly connected to opposite ends of the lift arm support shaft  55 . Lower link support shafts  57  are attached to inward surfaces at lower ends of right and left side frame portions of outer frame  51 . The two side plates of outer frame  51  act as mounting bases  58  for connecting the second mounting mechanisms  50  to the body frames  8 . Both right and left mounting bases  58  are detachably connected to the body frames  8  by the connecting bolts  36  attached to the outer frame  51  and body frames  8  through a plurality of bolt holes  58   a  formed in the mounting bases  34 .  
         [0042]    As shown in FIGS. 8, 9 and  10 , the second mounting mechanism  50  is detachably attached, through the mounting bases  58  of outer frame  31 , to inward surfaces adjacent the rear ends of right and left body frames  8  from which the first mounting mechanism  30  has been detached. The second mounting mechanism  50  has, arranged therein the top link bracket  54 , the pair of right and left lift arms  56  and the pair of right and left lower link support shafts  57 . A top link  60  having a forward end thereof pivotally connected to the top link bracket  54 , and the pair of right and left lower links  61  having forward ends thereof pivotally connected to the right and left lower link support shafts  57 , are pivotally connected at lower ends thereof to frames  71  of a rotary plow  70 , respectively. Lift rods  62  are connected between the right and left lift arms  56  and lower links  61 , respectively. These components constitute a link mechanism for vertically movably connecting the rotary plow to the vehicle body.  
         [0043]    As shown in FIG. 10, the lift arm support shaft  21  of the link mechanism for raising and lowering the mower unit  15  is connected through a link mechanism  63  to a control arm  59  attached to one end of lift arm support shaft  55 . When the lift arm support shaft  55  is rotated by the lift cylinder  22 , the right and left lift arms  56  are swung vertically to swing the right and left lower links  61  vertically relative to the body frames  8 , thereby vertically moving the plowing implement  70 .  
         [0044]    As shown in FIGS. 8, 9,  10  and so on, the power takeoff apparatus  40  is detachably supported by the support platform  53  of the second mounting mechanism  50  by tightening the mounting bolts  44  to connect the power takeoff case  41  of power takeoff apparatus  40  separated from the first mounting mechanism  30  to the rear surface of support platform  53  of the second mounting mechanism  50 . Then, a power transmission line is produced for transmitting power from the power supply shaft  7   e  of propelling transmission  7  to the plowing implement  70  through the power takeoff shaft  43  disposed by the power takeoff apparatus  40  in the rear middle position transversely of vehicle body, and through a rotary shaft  64 .  
         [0045]    That is, as shown in FIGS. 8, 9,  10  and so on, when the power takeoff apparatus  40  is supported by the support platform (i.e. support plate)  53 , the input shaft  42  of power takeoff apparatus  40  projects forward from the power takeoff case  41  to be placed rearwardly of and coaxial with the power supply shaft  7   e  of propelling transmission  7  by the positioning action of the second mounting mechanism  50 . The input shaft  42  is connected to the power supply shaft  7   e  to be separable and rotatable together by the coupling  42   a . The power takeoff shaft  43  is disposed rearwardly of the propelling transmission  7  and in the middle position transversely of the vehicle body, and projects rearward from the power takeoff case  41 . The power takeoff shaft  43  is connected to an input shaft of plowing implement  70  through the rotary shaft  64  with a universal joint  64   a  disposed in between. The torque of power supply shaft  7   e  of propelling transmission  7  may be taken out by the power takeoff apparatus  40  in the middle position transversely of the vehicle body. The power is transmitted from the power takeoff shaft  43  of power takeoff apparatus  40  through the rotary shaft  64  to the plowing implement  70  to drive tillage tines. The power transmission line from the power takeoff shaft  43  through the rotary shaft  64  to the plowing implement  70  extends linearly in the fore and aft direction of the vehicle body in plan view.  
         [0046]    According to this invention, the tractor may be converted not only to a grass cutting machine and a rotary cultivating machine, but also to a dust collecting machine with a dust collector attached to the vehicle body between the front and rear wheels, and a dust catcher disposed at the rear of the vehicle body to receive and store dust from the dust collector.