Treadmill

Abstract

A treadmill includes a front wheel unit and a rear guide unit that are spaced apart from each other and are connected to a base unit. The rear guide unit includes two positioning plates and two guide wheel assemblies connected to the positioning plates. Each of the guide wheel assemblies includes a plurality of roller subunits that are disposed around an axis and that are spaced apart from each other. A drive unit is operable to drive rotation of the front wheel unit. A running belt unit is looped around the front wheel unit and the guide wheel assemblies, such that the rotation of the front wheel unit drives circular motion of the running belt unit relative to the base frame unit.

What is claimed is: 
     
         1 . A treadmill comprising:
 a base frame unit;   a front wheel unit that is rotatably connected to said base frame unit;   a rear guide unit that is mounted to said base frame unit, that is spaced apart from said front wheel unit in a first direction, and that includes
 two positioning plates spaced apart from each other along an axis that is perpendicular to the first direction, and 
 two guide wheel assemblies respectively connected to said positioning plates, each of said guide wheel assemblies including a plurality of roller subunits that are disposed around the axis and that are spaced apart from each other; 
   a drive unit that is mounted to said base frame unit and that is operable to drive rotation of said front wheel unit; and   a running belt unit that is looped around said front wheel unit and said guide wheel assemblies, such that said rotation of said front wheel unit drives circular motion of said running belt unit relative to said base frame unit.   
     
     
         2 . The treadmill as claimed in  claim 1 , wherein, for each of said guide wheel assemblies, each of said roller subunits includes a bearing and a threaded member that extends through said bearing and that is threadedly secured to a respective one of said positioning plates. 
     
     
         3 . The treadmill as claimed in  claim 2 , wherein, for each of said guide wheel assemblies:
 said roller subunits are divided into a first group and a second group, each adjacent pair of said roller subunits belonging to said first group being spaced apart by at least two of said roller subunits belonging to said second group; and   each of said roller subunits belonging to said first group further includes a roller sleeve that is fixedly sleeved on said bearing.   
     
     
         4 . The treadmill as claimed in  claim 3 , wherein said roller sleeve of each of said roller subunits belonging to said first group has
 an outer surrounding surface that is substantially parallel to the axis, and   a block portion that protrudes from said outer surrounding surface and that abuts against said running belt unit such that said running belt unit is positioned relative to said base frame unit along the axis.   
     
     
         5 . The treadmill as claimed in  claim 4 , wherein said block portion of said roller sleeve has an inclined surface segment that is in contact with said running belt unit. 
     
     
         6 . The treadmill as claimed in  claim 1 , wherein:
 said base frame unit has
 a front end portion; 
 a rear end portion that is opposite to said front end portion in the first direction, 
 a pair of longitudinal bars that are elongated from said front end portion to said rear end portion in the first direction, and that are spaced apart from each other in a second direction perpendicular to the first direction, and 
 at least one transverse bar that is elongated in the second direction and that interconnects said longitudinal bars; 
   said front wheel unit is disposed adjacent to said front end portion of said base frame unit;   said rear guide unit is disposed adjacent to said rear end portion of said base frame unit; and   each of said positioning plates is connected to and movable along a respective one of said longitudinal bars.   
     
     
         7 . The treadmill as claimed in  claim 6 , wherein:
 each of said positioning plates has
 a plurality of adjustment slots that are elongated in the first direction, 
 a plurality of fasteners that extend respectively through said adjustment slots and that are fastened to said respective one of said longitudinal bars, and 
 an abutment protrusion; and 
   each of said longitudinal bars has
 a protrusion block, and 
 an adjustment bolt that extends threadedly through said protrusion block, and that abuts against said abutment portion of a respective one of said positioning plates, such that said adjustment bolt is rotatable to move relative to protrusion block and push said respective one of said positioning plates, via said abutment portion of said respective one of said positioning plates, to move in the first direction. 
   
     
     
         8 . The treadmill as claimed in  claim 7 , wherein:
 each of said positioning plates includes a main portion, a first bent portion that extends transversely from said main portion, and a second bent portion that extends transversely from said first bent portion away from said man portion;   said roller subunits of each of said guide wheel assemblies are rotatably mounted to said second bent portion of said respective one of said positioning plates; and   a distance between said main portions of said positioning plates along the axis is greater than a distance between said second bent portions of said positioning plates along the axis.   
     
     
         9 . The treadmill as claimed in  claim 8 , wherein:
 said second bent portion of each of said positioning plates has
 an outer periphery that is semi-circular and that extends around the axis, and 
 a plurality of mounting holes that are disposed adjacent to said outer periphery, that are arranged around the axis, and that are spaced apart from each other; and 
   said roller subunits of each of said guide wheel assemblies rotatably and respectively engage with said mounting holes of said respective one of said positioning plates.