The present invention relates to a hidden roller of a treadmill. A hidden roller set is pivotably connected at the bottom end of both hollow support arms by means of a pivot, respectively. As a result, the hidden roller sets can be received inside the hollow support arms when the treadmill base is placed in operational state, thereby avoiding an unexpected sliding shift. To the contrary, the hidden roller sets can be taken out when the treadmill base is folded up in storage position. Thus, the rollers are in contact with the ground and work with the fixed type roller set at the rear end of the base frame. Accordingly, the treadmill can be smoothly moved.

A foldable treadmill includes a base having two hollow side rails a slot is defined in an inner side of each of the two side rails and communicates with an interior of each side rail. A frame has two sides which are pivotably connected between two arms on the base by two links. An assistant frame is located between the two side rails of the base and has a first transverse bar and two support links are connected to the first transverse bar and pivotably connected to the underside of the frame. Two sub-wheels are connected to two extensions on two ends of the first transverse bar and movably received in the interior of the two side rails via the slots. The sub-wheels come out from the two openings when the frame is upright folded.

A treadmill includes a base which has two side tubes and each side tube has a slot defined in an inside thereof and an aperture is defined in an underside of each of the two side tubes. The two apertures communicate with an interior of the two side tubes. A folding device has a shaft with its two ends inserted in the two slots and two rollers are connected to the two ends of the shaft. Two side frames are connected to the shaft and two sides of an operation frame are pivotally connected to the two side frames. Two links are pivotally connected between the two side frames and the base. When folding the operation frame at an upright position, the two rollers are moved in the side tubes of the base and drop through the apertures to contact the floor so as to provide better support of the treadmill.

The present invention relates to a folding mechanism of an exercise treadmill having a treadmill frame and a support frame. A connecting rod is mounted on the support frame and extends to the front lower side of the exercise treadmill such that the other end of the connecting rod is pivotally connected the front portion of the treadmill frame. In addition, a ground touching roller is mounted to either side of the front end of the bottom of the treadmill frame. When the rear end of the treadmill frame is lifted to perform a folding action, the ground touching rollers are operative to facilitate the lifting action of an operator such that the operation is easy and has a labor-saving effect.

A folding collapsible treadmill includes base, a treadmill platform, the treadmill having a front side pivoted the base for enabling the treadmill platform to be turned relative to the base between a horizontal operative position and a vertical non-operative position, and a positioning apparatus installed adapted for locking the treadmill platform in the vertical non-operative position, the positioning apparatus including a stop member mounted in the treadmill platform, and a lever pivoted to one side of the treadmill platform and adapted for turning the movable stop member between a first position where the stop member is forced into engagement with the base to lock the treadmill platform in the vertical non-operative position, and a second position where the stop member is disengaged from the base for enabling the treadmill platform to be turned between the vertical non-operative position and the horizontal operative position.