Patent ID: 7694431

Claim:
A wheeled distance measuring device ( 10 ) comprising: a wheel ( 11 ) with a measuring unit ( 20 ) connected to a side of the wheel ( 11 ); a pole unit ( 30 ) having a first section ( 31 ), a second section ( 32 ) and a third section ( 33 ), the first section ( 31 ) having two first holes ( 311 ) defined through a wall located close to a first end thereof and the first end of the first section ( 31 ) movably inserted into a first end of the second section ( 32 ), the second section ( 32 ) having two second holes ( 321 ) defined through a wall thereof and located close to the first end of the second section ( 32 ), two third holes ( 322 ) defined through the wall of the second section ( 32 ) and located close to a second end of the second section ( 32 ), the second end of the second section ( 32 ) movably inserted into a first end of the third section ( 33 ) which has two fourth holes ( 331 ) defined through a wall thereof, the fourth holes ( 331 ) located close to the first end of the third section ( 33 ) and a second end of the third section ( 33 ) connected with the measuring unit ( 20 ); a first positioning unit ( 40 ) and a second positioning unit ( 40 ) located in the pole unit ( 30 ) and each of the first and second positioning units ( 40 ) including a first piece ( 42 ), two positioning members ( 43 ) and a second piece ( 44 ), the first positioning unit ( 40 ) located between the first and second sections ( 31 , 32 ) and the second positioning unit ( 40 ) located between the second and third sections ( 32 , 33 ), an action rod ( 41 ) having a first end inserted into the pole unit ( 30 ) via a second end of the first section ( 31 ) and the first end of the action rod ( 41 ) being in contact with the first piece ( 42 ) of the first positioning unit ( 40 ), the positioning members ( 43 ) of the first positioning unit ( 40 ) engaged with the first and second holes ( 311 , 321 ) when the first and second sections ( 31 , 32 ) are in extended position and the positioning members ( 43 ) of the first positioning unit ( 40 ) removed from the second holes ( 321 ) by pushing the action rod ( 41 ) to move the first piece ( 42 ) so that the first and second sections ( 31 , 32 ) are retractable to each other, the positioning members ( 43 ) of the second positioning unit ( 40 ) engaged with the third and fourth holes ( 322 , 331 ) when the second and third sections ( 32 , 33 ) are in extended position and the positioning members ( 43 ) of the second positioning unit ( 40 ) removed from the fourth holes ( 331 ) by moving the first piece ( 42 ) of the second positioning unit ( 40 ) so that the second and third sections ( 32 , 33 ) are retractable to each other, and a handle ( 50 ) connected to the second end of the first section ( 31 ) and including a slot ( 51 ) through which a second end of the action rod ( 41 ) extends.