preferred embodiments of the present invention will be described next with reference to the accompanying drawings . fig1 shows a general side view of a riding type law mower vehicle having a mower m relating to one preferred embodiment of the invention . fig2 shows a general plan view of the mower . this riding type law mower vehicle includes a traveling vehicle body 3 constructed as a rear wheel drive type vehicle having steerable front wheels 1 and non - steerable rear wheels 2 . to the lower side of the traveling vehicle body 3 , there is connected or suspended the mower m via a link mechanism 4 so that the mower m can be raised or lowered in parallel relative to the vehicle body . at a front portion of the traveling vehicle body 3 , there is mounted a vertical shaft type engine 5 . vertical shaft rotational force taken off an output shaft 6 projecting downward from the engine 5 is belt - transmitted in distribution a transmission case 31 mounting the rear wheels 2 and to the mower m , respectively . as shown in the plan view of fig2 , the mower m is constructed as a twin - blade type mower having two cutting blades 8 , 9 mounted to a laterally longitudinal oval shaped deck 7 in right / left juxtaposition to be driven by vertical shafts associated respectively therewith . more particularly , the respective cutting blades 8 , 9 are operably connected to deck side inner end portions of cutting blade drive shafts 10 , 11 mounted to and extending through right and left portions in the top face of the deck 7 . the cutting blades 8 , 9 each comprises a bar blade forming a cutting edge ( a ) on one of opposed ends of band - plate like steel member and forming a wind generating blade ( wing portion ) ( b ) on the other side of the opposed ends . an input shaft 12 is provided at a rear portion in the right / left center of the top face of the deck 7 . a belt 15 is tensely entrained around an input pulley 13 fitted on this input shaft 12 and an output pulley 1 fitted on the output shaft 6 of the engine 5 . also , a single belt 21 is tensely entrained around a cutting blade drive pulley 16 fitted on the input shaft 12 , driven pulleys 17 , 18 fitted on the respective cutting blade drive shafts 10 , 11 and a guide pulley 19 and a tension pulley attached to the deck 7 . with these means comprised of the above - described pulleys and belts , the two cutting blades 8 , 9 are driven to rotate in mutually opposite directions . and , the rotational directions of the two cutting blades 8 , 9 are set such that on vehicle body - wise rear sides of rotational axes ( p ), ( q ) thereof , rotational paths of the leading ends of the two cutting blades 8 , 9 are in inward opposition to each other . the mower m is disposed with a slight inclination such that the rotational axis ( p ) of the cutting blade 8 disposed on the left side of the vehicle body in the plan view is located forwardly of the rotational axis ( q ) of the cutting blade 9 disposed on the right side of the vehicle body and as the leading end rotational paths of the two cutting blades 8 , 9 are slightly overlapped in the fore and aft direction , there will not occur mowing failure of grass between the two cutting blades 8 , 9 . as shown in fig3 , at a front center portion and a rear center portion inside the deck 7 , there are mounted a front vacuum plate 22 and a rear vacuum plate 23 , the vacuum plates having a mountain - like shape in plan view thereof , so that approximately circular cutting chambers 24 , 25 are formed for the respective cutting blades 8 , 9 along the leading end rotational paths thereof . top portions of the front vacuum plate 22 and the rear vacuum plate 23 are in spaced opposition to each other , thus forming an opening 26 between the two cutting chambers 24 , 25 for allowing flow passage of cut grass therethrough in / out of the respective chambers . as shown in the vertical sectional side view of fig4 , a peripheral wall ( s ) and an upper wall ( u ) of each cutting chamber 24 , 25 is connected to each other via a corner guide face ( c ) having an arcuate shape in cross section , the guide face ( c ) being concavely curved toward the inner lower side . as shown in fig3 , in the cutting chamber 24 disposed on the left side of the vehicle body , at a peripheral end of the peripheral wall ( s ) formed by the rear vacuum blade 23 facing the opening 26 , there is formed a linear peripheral guide face ( g ) for guiding cut grass flowing on the cutting air current generated by the left side cutting blade 8 toward the right side cutting chamber 25 . and , an extension line of this peripheral guide face ( g ) is configured to extend to the vicinity of the rotational axis ( q ) of the right side cutting blade 9 . at a laterally outer portion of the right side cutting chamber 25 , there is formed a cut grass discharging outlet 28 . when this cut grass discharging outlet 28 is closed , there is provided a mulching mode of the mower in which cut grass is mulched repeatedly and discharged to the outside while the grass is carried in and out of the two cutting chambers 24 , 25 . whereas , when a lid cover 27 is removed to open up the cut grass discharging outlet 28 , there is provided a side discharging mode of the mower in which the cut grass is guided to the cut grass discharging outlet 28 to be discharged to the right side of the vehicle body . in the mulching mode , the grass cut in the respective cutting chambers 24 , 25 is mulched repeatedly as being carried around and circulated with rotations of the cutting blades 8 , 9 . in this case , the cut grass conveyed by the cutting air currents generated by the cutting blades 8 , 9 is caused to flow in the peripheral direction along the peripheral walls ( s ), in the course of which the grass is guided by the corner guide face ( c ) toward the upper walls and then to fall down again as losing its velocity , thus being subjected to cutting actions of the cutting blades 8 , 9 . a portion of the grass circulating within the left side cutting chamber 24 will be guided along the peripheral guide face ( g ) toward the opening 26 and will then enter the right side cutting chamber 25 to be subjected to a cutting action of the cutting blade 9 . in this case , as the peripheral guide face ( g ) is oriented toward the vicinity of the rotational axis ( q ) of the cutting blade 9 , the grass flown into the cutting chamber 25 will flow along a direction substantially normal to the rotational direction of the cutting blade 9 , so that this grass will collide the cutting air current and other grass circulating within the cutting chamber 25 , so that the entered grass will lose its velocity and be subjected to the cutting action of the cutting blade 9 in an efficient manner . in the side discharging mode with opening up the cut grass discharging outlet 28 with removal of the lid cover 27 , the grass in the right side cutting chamber 25 will first flow along the peripheral wall ( s ) on the front side of the vehicle body and then be discharged through the cut grass discharging outlet 28 to the right side of the vehicle body . the grass in the left side cutting chamber 24 will flow along the rear side peripheral wall ( s ), in the course of which this grass will enter , through the opening 26 , the right side cutting chamber 25 and then be discharged from the cut grass discharging outlet 28 as being conveyed on the cutting air current of the cutting blade 9 being rotated . in this side discharging mode , by switching a discharge cover 29 attached to the right end of the deck 7 to be pivotally raised relative thereto , into a posture protruding over the cut grass discharging outlet 28 , the grass discharged from the cut grass discharging outlet 28 can be guided onto the ground surface without being scattered about upward . ( 1 ) as shown in fig5 , the corner guide face ( c ) interconnecting the peripheral wall ( s ) and the upper wall ( u ) can be formed as a straight inclined face extending obliquely downward . ( 2 ) as shown in fig6 , the deck 7 can have a such cross sectional shape with the peripheral wall ( s ) and the upper wall ( u ) extending continuously at a right angle relative to each other , and at its corner portion , a baffle member 30 made of resin material or the like can be attached , thus forming a corner guide portion ( c ) extending inwardly and downwardly . ( 3 ) as shown in fig7 , at the peripheral end of the peripheral wall ( s ) formed by the rear vacuum plate 23 facing the opening 26 , there can be formed a peripheral guide face ( g ) for guiding grass scattered by the left side cutting blade 8 toward the right side cutting chamber 25 and a peripheral guide face ( g ) for guiding grass scattered by the right side cutting blade 9 toward the left side cutting chamber 24 . and , the extension line of each peripheral guide face ( g ) may be configured to extend to the vicinity of the rotational axis ( q ), ( p ) of the cutting blade 9 , 8 . with these , mutual flows in / out of grass between the two cutting chambers 24 , 25 may be promoted , thus enhancing the mulching efficiency . ( 4 ) as shown in fig8 , the invention may be embodied still alternatively with providing only one peripheral guide face ( g ) for promoting the grass flow from the right side cutting chamber 25 to the left side cutting chamber 24 . ( 5 ) the invention may be embodied as a mower designed for the mulching mode only , having no cut grass discharging outlet 28 . ( 6 ) the invention may be embodied with adopting the above - described construction for adjacent pair of cutting blades to a mower having three cutting blades driven by vertical shafts and juxtaposed along the right / left direction .
a mower includes a mower deck that opens downward ; a plurality of vertical shafts rotatably supported by the mower deck ; a plurality of cutting blades driven by the vertical shafts inside the mower deck ; a cutting chamber formed inside the mower deck and provided for each cutting blade ; and an opening formed between the cutting chambers for adjacent cutting blades . the cutting blades are arranged generally in a lateral direction with an adjacent pair of cutting blades being rotatably driven in opposite directions from each other . the opening allows for flow passage of cut grass at least from one of the cutting chambers to the other cutting chamber .