Treadmill with collapsible handrails

A step exercising machine comprising a machine base, a track, two rollers transversely mounted on said machine base to hold said track, a front upright frame and a rear upright frame mounted on said machine base at two opposite ends, a first horizontal handrail and a second horizontal handrail respectively connected between said front and rear upright frames at either side at the top, a bottom board mounted on said machine base below said track, and a control panel mounted on said first horizontal handrail for controlling the operation of the step exercising machine, wherein:

• said machine base comprises a front cross bar, and two parallel side bars having a respective front end perpendicularly connected to said front cross bar at either end by screw bolts, said front cross bar comprising two mounting frames near two opposite ends thereof at the top;
• said front upright frame comprises two upright tubes, and a bottom cross bar connected between the upright tubes thereof at the bottom and retained to said mounting frames of said front cross bar of said machine base by first clamping plates, each first clamping plate being bridged over the bottom cross bar of said front upright frame and having two opposite ends fastened to either mounting frame by screw bolts;
• and
• said rear upright frame comprises two upright tubes, and a bottom cross bar connected between the upright tubes thereof at the bottom and retained to said side bars of said machine base at the bottom by second clamping plates, the bottom cross bar of said rear upright frame having two embossed surface portions spaced near two opposite ends thereof onto which said second clamping plates respectively clamp, each second clamping plate being bridged over the bottom cross bar of said rear upright frame and having two opposite ends fastened to either side bar of said machine base by screw bolts.