Abstract:
A lawn mower comprises a blade drive shaft with a blade rotatably mounted inside a mower deck supported by a vehicle body, a blower unit including a cylindrical blower housing connected to a grass clippings discharging section provided in a side end region of the mower deck, a vertical drive shaft having a shaft portion with vanes attached thereto inside the blower housing and a shaft portion extending upward through the blower housing, and a discharging sleeve projecting rearwardly along an outer tangent line of the blower housing, a grass collecting apparatus mounted rearwardly of the vehicle body, a duct for allowing the discharging sleeve to communicate with the grass collecting apparatus, and a belt-type blower driving mechanism for driving the vertical drive shaft of the blower unit. The belt-type blower driving mechanism includes an intermediate vertical shaft disposed rearwardly of the blower housing, and a belt transmission unit for transmitting power from the blade drive shaft to the vertical drive shaft through the intermediate vertical shaft.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a lawn mower adapted to collect grass clippings cut by a mower unit in a grass collecting apparatus mounted rearwardly of a vehicle body. 
   2. Description of the Related Art 
   A conventional lawn mower of the above-noted type is known from U.S. Pat. No. 5,224,327 and Japanese Patent Application “Kokai” No. 8-322355, for example, which comprises a mower unit including a mower deck having bar blades driven to rotate about vertical axes and a grass clippings discharge outlet formed in a side end of the mower deck, the mower unit being attached to a vehicle body to be vertically movable, a grass collecting apparatus mounted rearwardly of the vehicle body, and a blower unit mounted above the grass clippings discharge outlet of the mower deck to be driven by a vertical shaft and operatively connected to a blade driving line, wherein grass clippings discharged from the grass clippings discharge outlet are forcibly transported to the grass collecting apparatus through the blower unit and a duct. 
   The conventional lawn mower noted above employs a belt transmission mechanism in which a blade drive shaft of the bar blade positioned closest to the grass clippings discharge outlet is interlocked with a lower end portion of an intermediate vertical shaft by winding a belt thereon while an upper end portion of the intermediate vertical shaft is interlocked with an impeller drive shaft projecting upwardly of a blower housing by winding a belt thereon, thereby to transmit power taken from the blade driving line provided above the mower deck to a blower input portion provided in a higher position. With this arrangement, however, the relay intermediate vertical shaft is mounted forwardly of the blower housing, as a result of which pulleys provided in the upper and lower end portions of the intermediate vertical shaft disadvantageously project to a large extent forwardly of the blower housing. 
   A blower drive mechanism including the intermediate vertical shaft is incorporated in the blower unit as one unit and attachable to and detachable from the mower deck. As described above, the intermediate vertical shaft is mounted forwardly of the blower unit, which increases a dimension from a front end of the blower drive mechanism to a rear end of a discharging sleeve projecting rearwardly of the blower housing. Consequently, such a blower unit is cumbersome to handle when attached to or removed from the mower deck and requires a large storage space when removed. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a compact arrangement of the blower unit and blower driving mechanism to facilitate handling and storage thereof in order to solve the above-noted problems of the prior art. 
   In order to fulfill the above object, a lawn mower according to the present invention comprises a mower deck supported by a vehicle body, a blade drive shaft with a blade rotatably mounted inside the mower deck, a grass clippings discharging section provided in a side end region of the mower deck, a blower unit including a cylindrical blower housing connected to the grass clippings discharging section, a vertical drive shaft having a shaft portion with vanes attached thereto inside the blower housing and a shaft portion extending upward through the blower housing, and a discharging sleeve projecting rearwardly along an outer tangent line of the blower housing, a grass collecting apparatus mounted rearwardly of the vehicle body, a duct for allowing the discharging sleeve to communicate with the grass collecting apparatus, a belt-type blade driving mechanism mounted above a top wall of the mower deck for driving the blade drive shaft, and a belt-type blower driving mechanism for driving the vertical drive shaft of the blower unit by utilizing power transmitted from the belt-type blade driving mechanism. The blower driving mechanism includes an intermediate vertical shaft disposed rearwardly of the blower housing, and a belt transmission unit for transmitting power from the blade drive shaft to the vertical drive shaft through the intermediate vertical shaft. 
   In this arrangement, the intermediate vertical shaft constituting a core element of the blower driving mechanism is disposed in a dead zone defined rearwardly of the blower housing, which prevents the blower driving mechanism from putting any spatial pressure on other elements and reduces the fore-and-aft dimensions of the blower unit per se having the blower driving mechanism integrated therewith, compared with the conventional arrangement. Thus, the blower unit is easily attached to or detached from the mower deck with the benefits of compactness in the fore-and-aft dimensions of the blower unit having the blower driving mechanism integrated therewith, which also reduces the storage space for the removed blower unit. 
   Further, for providing an optimal arrangement of the intermediate vertical shaft constituting the core element of the blower driving mechanism, it is proposed that the intermediate vertical shaft is mounted in a corner area defined by an outer peripheral wall of the blower housing and the discharging sleeve. With this arrangement, the blower driving mechanism is free from interference with the other elements, while quite a rational arrangement is provided for the blower unit and the blower driving mechanism. 
   According to one preferred embodiment of the present invention, the belt transmission unit includes belt pulleys mounted on the blade drive shaft and the intermediate vertical shaft, a belt wound around the pulleys, and a tension clutch switchable between a disengaging position for breaking the power transmission ability of the belt and an engaging position for maintaining the power transmission ability of the belt. With this arrangement, in attaching and detaching the blower unit having the blower driving mechanism integrated therewith to/from the mower deck, the belt wound between the blade drive shaft and the intermediate vertical shaft can be maintained in a loose state by maintaining the tension clutch in the disengaging position. Also, when the mower unit is driven idle for cleaning the interior of the mower deck, the tension clutch is switched to the disengaging position, which prevents the blower unit from being driven unnecessarily and allows only the mower unit to be driven. 
   Other features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments to be taken with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation of a lawn mower; 
       FIG. 2  is a plan view of the lawn mower; 
       FIG. 3  is a plan view of a mower unit; 
       FIG. 4  is a plan view of a blower unit in cross section; 
       FIG. 5  is a side view of the blower unit in vertical section; 
       FIG. 6  is a rear view of the blower unit in vertical section; 
       FIG. 7  is a side view of a principal portion of the blower unit in vertical section; 
     FIG.  8 A and  FIG. 8B  are plan views of a tension clutch; 
       FIG. 9  is a side view of a grass collecting apparatus in vertical section; 
       FIG. 10  is a rear view of the grass collecting apparatus in vertical section; 
       FIG. 11  is a side view showing part of the grass collecting apparatus in vertical section with a guide cover being opened; 
       FIG. 12  is an exploded perspective view of the grass collecting apparatus; and 
       FIG. 13  is a side elevation of the lawn mower with the grass collecting apparatus being opened. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   FIG.  1  and  FIG. 2  show a lawn mower relating to the present invention in side elevation and in plan view, respectively. The lawn mower comprises a running vehicle body  3  having a right and left pair of caster-type front wheels  1  and a right and left pair of rear drive wheels  2 . A mower unit M is suspended from the underside of the running vehicle body  3  between the front and rear wheels through a right and left pair of four-point linkage mechanisms  4  each having a front link  4   a , a rear link  4   b  and a lower connecting link  4   c . The linkage mechanisms are vertically movable by a hydraulic cylinder  5  thereby to move the mower unit M vertically in a generally parallel movement. A motor section  7  housing an engine  6  projects rearwardly of the rear wheels  2 . A grass collecting apparatus  8  for collecting grass clippings is mounted across the motor section  7 . A driver&#39;s seat  9  is disposed forwardly of the motor section  7 , and a gate-shaped rollover protective structure (ROPS)  10  is mounted between the driver&#39;s seat  9  and the motor section  7 . 
   A detailed description of the vehicle construction is omitted here. Output from the engine  6  is inputted to a counter casing  11  and divided into a propelling line and a working line. Power in the propelling line is inputted to an unillustrated right and left pair of hydraulically operable stepless hydrostatic transmissions (HSTs) provided at opposite sides of the counter casing  11 . Power output in varied speeds is transmitted from the respective HSTs to the right and left rear wheels  2  individually through reduction cases  12 . The stepless hydrostatic transmissions for driving the right and left rear wheels  2  are shiftable by a pair of right and left propelling levers  13  individually which are provided at opposite sides of the driver&#39;s seat  9  to be rockable back and forth, thereby to steplessly change forward and backward speeds of the right and left rear wheels  2  independently. The right and left propelling levers  13  are operable to selectively establish a forward or rearward straight running state, a turning state with the right and rear wheels  2  driven at different speeds, a pivot turn with one of the rear wheels  2  standing still, and a spin turn with the right and left rear wheels  2  driven in opposite directions. The branched drive power for the working line is outputted forwardly from a PTO shaft  14  projecting from a lower front portion of the counter casing  11  to be transmitted to the mower unit M. 
   As illustrated in  FIG. 3 , the mower unit M includes a mower deck  15  opening downward and including three bar blades  16 ,  17  and  18  mounted therein to be rotatable about vertical axes. These blades are arranged in juxtaposition and shaft-supported by the mower deck. The mower deck  15  is constructed as a flat deck with an upper wall having a uniform height over the entire deck. A discharge section forming a discharge outlet “d” is provided at a right end portion of the deck. 
   The working drive power taken from the PTO shaft  14  is transmitted to a bevel gear casing  19  mounted on a central top surface of the mower deck  15  through a flexible and extendible and contractible shaft transmission mechanism  20 . The rotary power converted to rotation about a vertical axis in the bevel gear casing  19  is transmitted to a rotary shaft  17   a  of the central bar blade  17 . The rotary shaft  17   a  and rotary shafts  16   a  and  18   a  of the right and left bar blades  16  and  18  are interlocked with each other through a belt  21  wound thereon. All of the bar blades  16 ,  17  and  18  are rotated in the same direction (clockwise as viewed from above) so that front halves of loci of rotation of the bar blades  16 ,  17  and  18  are directed toward the discharge outlet “d”. Further, freely rotatable wheels (anti-scalp rollers)  22  are provided around the mower deck  15  for riding obstacles. 
   A blower unit B is attached to the right end portion of the mower deck  15  of the mower unit M, as described hereinafter, to be driven for forcing grass clippings discharged from the discharge outlet “d” toward the grass collecting apparatus  8  at the rear of the vehicle body. 
   As shown in  FIGS. 3 through 7 , the blower unit B includes a blower housing  31  connected to the discharge outlet “d” of the mower deck  15 , and an impeller  32  supported by an upper wall of the blower housing  31  to be rotatable about a vertical axis. The blower housing  31  is connected and fixed to a support frame  33  U-shaped in plan view and mounted on the right end portion of the mower deck  15 . The support frame  33  is connected at front and rear ends thereof to connecting elements  34  fixed to the deck through connecting pins  35  to be detachable by removing the connecting pins  35  to separate the blower unit B from the discharge outlet “d” for the purpose of maintenance. The support frame  33  connecting and supporting the blower housing  31  also serves as a guard frame surrounding the blower housing  31 . 
   An intermediate vertical shaft  36  is mounted at the rear of the support frame  33 . A belt  39  is wound in tension between a pulley  37  mounted on a lower end portion of the intermediate vertical shaft  36  and a pulley  38  mounted on an upper end portion of the blade drive shaft  18   a  of the right-end bar blade  18 , while a belt  43  is wound in tension between a pulley  40  mounted on an upper end portion of the intermediate vertical shaft  36  and a pulley  42  of an impeller drive shaft  41  protruding from a top surface of the blower housing  31 . Thus, the blower unit B is driven by the power taken from the blade driving line. 
   The belt  39  for operatively interconnecting the blade drive shaft  18   a  and the intermediate vertical shaft  36  is provided in a position higher than the blade driving belt  21 . As shown in  FIG. 1 , the lower connecting link  4   c  of the linkage mechanism  4  is inclined to extend upwardly and rearwardly to be connected to the mower deck  15  so that the pulley  38  and the belt  39  are accommodated, free from interference, in a vertically enlarged space defined between a rear portion of the lower connecting link  4   c  of the right-side linkage mechanism  4  and the upper surface of the deck. 
   The belt  29  wound around and operatively interconnecting the blade drive shaft  18   a  and the intermediate vertical shaft  36  and the belt  43  wound around and operatively interconnecting the intermediate vertical shaft  36  and the impeller drive shaft  41  are pressed tight by tension rollers  44  and  45 , respectively. The tension roller  44  acting on the belt  39  acts also as a tension clutch  46  for breaking and establishing power transmission from the blade drive shaft  18   a  to the intermediate vertical shaft  36 . More particularly, as shown in  FIGS. 8A and 8B , the tension roller  44  is carried by a tension arm  47  swingable about a pivotal shaft Pa disposed on the blower unit. The tension arm  47  is operatively connected to a switching control lever  48  mounted on the blower unit to be selectively swingable about a control shaft Pb disposed on the blower unit through a curved link  49  and a spring  50 . The switching control lever  48  is pivotable beyond a dead point to be selectively maintained between an engaging position for pressing the tension roller  44  against the belt  39  by a tensile force of the spring  50  and a disengaging position for moving the tension roller  44  sufficiently away from the belt  39  to relieve the tension. The tension roller  45  is also carried by a tension arm  52  supported to be swingable about the pivotal shaft Pa and pivotably urged in a fixed direction by a spring  51 , thereby to constantly maintain the belt  43  under tension. 
   As described above, the blower driving mechanism including the intermediate vertical shaft  36 , the tension arms  47  and  52 , the belt  43 , the switching control lever  48  and the like is incorporated in the blower unit B as an integral part thereof. In order to detach the blower unit from the mower deck  15 , the belt  39  is removed from the pulley  38  of the blade drive shaft  18   a  to remove the connecting pins  35  with the tension clutch  46  being maintained in the disengaging position. On the other hand, a reversed process is carried out to attach the blower unit to the mower deck  15 , and then the belt  39  is wound around the pulley  38  to switch and maintain the tension clutch  46  in the engaging position. 
   The intermediate vertical shaft  36  is mounted upright and positioned in a corner formed inwardly of the vehicle body and enclosed by a discharge sleeve  31   a  projecting rearwardly from an outer peripheral position of the blower housing  31  and a circular outer periphery of the blower housing  31 . Thus, the blower drive mechanism is accommodated in the interior of the support frame  33  compactly in both the fore-and-aft and sideways directions. 
   A cylindrical duct  53  is detachably inserted in and connected to the discharge sleeve  31   a  of the blower housing  31  in the blower unit B installed and driven as set forth above for guiding and supplying the grass clippings forcibly discharged by the impeller  32  to the grass collecting apparatus  8  mounted on the rear of the vehicle body. 
   The grass collecting apparatus  8  is adapted to collect the grass clippings transported through the duct  53  in two grass catching bags  60  mounted on opposite sides of the motor section  7 . The construction thereof will be described hereinafter. 
   Grass catcher frames  61  made of pipes are connected through pins between lateral post portions of the rollover protective structure  10  and engine mounting frames  23  below the motor section  7 . A cross frame  61   a  extends between upper portions of the grass catcher frames  61 , and four bag supporting arms  62  extend rearward from the cross frame  61   a . A right and left pair of bag connecting sections  63  are distributed to opposite sides of the motor section  7 , each defined by the two bag supporting arms  62 . The duct  53  is detachably connected at a rear end thereof to the grass collecting apparatus at a right-side position thereof, while a guide cover  65  with an entire area thereof opening downward is mounted on the grass catcher frames  61  to be vertically pivotable about a pivotal point “c” between an open position and a closed position. 
   Each of the grass catching bags  60  is a rectangular bag made of sewn cloth of high air permeability. A core frame  66  made of a metal bar is sewn to an upper opening edge of the bag to maintain the opening edge of the bag in a rectangular shape. The opening edge maintained in its shape by the core frame  66  is placed on top surfaces of the two bag supporting arms  62  in each bag connecting section  63  and supported by a lower edge portion of the closed guide cover  65 , thereby to prevent lifting of the grass catching bag  60 . 
   The two sets of bag supporting arms  62  constituting the right and left bag connecting sections  63  are provided in a position slightly higher than an engine hood  24  in the motor section  7 . A bottom plate  67  extends between the two inner bag supporting arms  62  so as to overlap the engine hood  24 . The bottom plate  67  forms a tunnel passage  68  within the guide cover  65  when the latter is lowered, to interconnect upper spaces in the right and left bag connecting sections  63 . The grass clippings fed into the right side of the guide cover  65  through the duct  52  are guided by the guide cover  65  to the right and left grass catching bags  60 . Air flows entraining the grass clippings and blown into the guide cover  65  are directed to an air discharge passage  70  through a mesh-like air discharge outlet  69  formed on an inner surface of a rear portion of the guide cover  65 , thereby to be discharged rearwardly and downwardly. 
   For inspection and maintenance of the motor section  7 , as illustrated in  FIG. 13 , the pin-connection between the grass catcher frames  61  and the rollover protective structure frame  10  is released, and the entire grass catcher frames  61  is swung rearwardly about a pin connecting point “e” connecting the frames to the engine mounting frames  23 , thereby to produce an open space around the motor section  7 .