Integrated transaxles for standing lawn mower

Abstract

A standing lawn mower includes right and left side integrated transaxles for operating the right and left drive wheels independently. The integrated transaxles may include independent hydraulic systems and hydraulic fluid for modularity and reduced risk of cross contamination. The operator support platform is at least partially behind the right and left integrated transaxles.

What is claimed is: 
     
         1 . A standing lawn mower comprising:
 a frame;   a right drive wheel supporting the frame;   a left drive wheel supporting the frame;   a prime mover supported by the frame;   a cutting deck assembly supported by the frame for movement between a cutting position in which the cutting deck assembly is lowered with respect to the frame and a travel position in which the cutting deck assembly is raised with respect to the frame, the cutting deck assembly including a cutting deck and at least one cutting blade mounted under the cutting deck and rotating under the influence of the prime mover to cut vegetation when the cutting deck assembly is in the cutting position;   a right side integrated transaxle operating under the influence of the prime mover to drive rotation of the right drive wheel independent of the rotation of the left drive wheel, the right side integrated transaxle including a right side housing, a right hydraulic pump within the housing, and a right hydraulic motor within the housing;   a left side integrated transaxle operating under the influence of the prime mover to drive rotation of the left drive wheel independent of the rotation of the right drive wheel, the left side integrated transaxle including a left side housing, a left hydraulic pump within the housing, and a left hydraulic motor within the housing; and   an operator platform for supporting a standing operator of the lawn mower, the operator platform being positioned at least partially behind the right and left integrated transaxles.   
     
     
         2 . The standing lawn mower of  claim 1 , wherein the right transaxle includes a right hydraulic system using right hydraulic fluid; and wherein the left transaxle includes a left hydraulic system independent of the right hydraulic system and using left hydraulic fluid that is separate and unmixed with the right hydraulic fluid. 
     
     
         3 . The standing lawn mower of  claim 1 , wherein the operator platform is at least partially between the right and left drive wheels. 
     
     
         4 . The standing lawn mower of  claim 1 , wherein the prime mover includes a horizontal PTO shaft; the standing lawn mower further comprising a gear box taking as an input torque from the horizontal PTO shaft and delivering as an output a vertical rotating shaft. 
     
     
         5 . The standing lawn mower of  claim 1 , wherein the prime mover includes a vertical, downwardly extending PTO shaft that defines a vertical PTO axis, the PTO shaft rotating about the PTO axis during operation of the prime mover. 
     
     
         6 . The standing lawn mower of  claim 5 , wherein the prime mover includes a PTO bearing supporting the PTO shaft in cantilevered fashion for rotation about the PTO axis; and wherein all portions of both the right side transaxle and the left side transaxle are below a horizontal plane that is below the PTO bearing. 
     
     
         7 . The standing lawn mower of  claim 5 , further comprising a power transmission assembly including: a PTO sheave mounted to the PTO shaft for rotation with the PTO shaft about the PTO axis; a right transaxle sheave interconnected with the right hydraulic pump and rotatable to drive operation of the right hydraulic pump; a left transaxle sheave interconnected with the left hydraulic pump and rotatable to drive operation of the left hydraulic pump; an idler; a tensioner; and a belt interconnecting the PTO sheave to the right transaxle sheave, left transaxle sheave, idler, and tensioner to transmit rotation of the PTO sheave under the influence of the PTO shaft into rotation of the right transaxle sheave, left transaxle sheave, idler, and tensioner; wherein each of the right transaxle sheave, left transaxle sheave, idler, and tensioner rotate about an axis of rotation that is parallel to the PTO axis. 
     
     
         8 . The standing lawn mower of  claim 1 , wherein the operator platform is positioned at least partially behind the right and left drive wheels. 
     
     
         9 . The standing lawn mower of  claim 1 , further comprising a hydraulic fluid expansion tank; and wherein the right side integrated transaxle, the left side integrated transaxle, and the hydraulic fluid expansion tank are in fluid communication with each other.