Adjustable air resistance force generating device for exercisers

Abstract

An air resistance force generating device for exercisers includes a tubular casing driven by the user and having a shaft rotatably received therein. A plurality of frames extend radially outward from the casing and each frame is a closed frame so as to enclose a through space. A plurality of blades each have one end thereof reeving through the shaft and the other end of the each blade is slidably received in the frame corresponding thereto. An adjusting member is connected to an end of the casing and the shaft has an end fixed to the adjusting member so that the blades can be wrapped around the shaft by rotating the adjusting member.

What is claimed is:  
     
         1 . An air resistance force generating device for exercisers, comprising: 
 a tubular casing having a shaft rotatably received therein and an adjusting member connected to an end of the casing, the shaft having an end fixed to the adjusting member;    a plurality of frames connected to the casing and extending radially outward from the casing, each frame being a closed frame so as to enclose a through space, and    a plurality of blades each having one end thereof reeving through the shaft and the other end of the blades slidably received in the frames.    
     
     
         2 . The device as claimed in  claim 1 , wherein the casing has two grooves defined in an inner periphery thereof and a block is movably mounted to the shaft, the block having two ridges which are slidably engaged with the grooves.  
     
     
         3 . The device as claimed in  claim 2 , wherein the shaft includes a section of outer threaded periphery and the block has a hole with an inner threaded periphery which is threaded engaged with the outer threaded periphery.  
     
     
         4 . The device as claimed in  claim 1 , wherein two bars transversely extend through the casing and the shaft has two notches defined transversely in an outer periphery thereof, the two bars engaged with the two notches so as to limit the shaft from moving longitudinally.  
     
     
         5 . The device as claimed in  claim 1 , wherein the shaft includes a polygonal shaped end and the adjusting member has a recess such that the polygonal shaped end is securely engaged with the recess.  
     
     
         6 . The device as claimed in  claim 5 , wherein the adjusting member has a passage defined therethrough which is in communicating with the recess, a bolt extending through the passage and being threaded connected to a threaded hole defined in polygonal shaped end of the shaft.  
     
     
         7 . The device as claimed in  claim 1 , wherein each frame has an engaging groove defined in an inner periphery thereof and the blade is slidably engaged with the engaging groove.  
     
     
         8 . The device as claimed in  claim 1 , wherein each frame has a spring which has one end thereof fixed to the frame and the other end of the spring is connected to the blade.