Abstract: The transmission system of an exercise bicycle includes a first drive shaft mounted rotatably on the rear end portion of a frame and provided with foot pedal cranks on two ends thereof, second and third drive shafts mounted rotatably on the frame, a one-way clutch secured on the second drive shaft, a first sprocket mounted securely on the first drive shaft, second and third sprockets mounted securely on the second drive shaft, a fourth sprocket mounted securely on the third drive shaft, a fifth sprocket mounted securely on an axle of a resistance wheel that is mounted rotatably on a front end portion of the frame, a first drive chain trained between the first sprocket and the one-way clutch, a second drive chain trained between the second and fifth sprockets, and a third drive chain trained between the third and fourth sprockets.

Abstract: An arm lever for an exercise bicycle has a pivot portion to be mounted pivotally on a front end portion of a bicycle frame and a bottom end to be connected to an end of a crank arm. The bottom end of the arm lever is provided with a locking plate which has a forked extension with a distal bottom end, an upright slit that opens from the distal bottom end, and a plurality of spaced locking holes that extend through the slit. The slit permits the extension of the end of the crank arm therein. The forked extension is connected to the crank arm at a selected one of the locking holes to vary the distance of the end of the crank arm from the pivot portion and vary correspondingly the range of pivoting movement of the arm lever to suit the user's physique.

Abstract: Method of making an improved sandwich type insulation wall having internal framework formed by channel bars and transverse members bridging two adjacent channel bars. A plurality of channel bars having lateral wings are erected to form the main skeleton; the spaces between the channel bars are filled with pieces of resilient insulating material of proper size and shape by inserting their edges into the channels of the bars to secure them in place; transverse members are positioned at both sides of the insulating material between and connected to the channel bars; wire panels are mounted to cover the whole area of the wall spaced from the insulating board by the wings and transverse members; and both sides of the structure are grouted with a proper thickness of grouting cement or vermiculite.