Angle-adjusting device for a treadmill frame

An angle-adjusting device adapted to be mounted under a belt frame of a treadmill, and comprising:

• a pair of attachment blocks adapted to be firmly and respectively attached to two side under the belt frame, and each attachment block has a transverse opening therein;
• a pair of polygonal feet operationally attached respectively to one corresponding attachment block, and each polygonal foot including,
• two symmetrical polygonal plates, each having multiple edges with different lengths and a pin opening defined in each polygonal plate to correspond to the transverse opening of the pair of attachment blocks, wherein the pin opening is figure-eight shaped and has a first and a second round portion partially overlapping each other,
• a pin moveably penetrating the pin opening in the two symmetrical polygonal plates and extending through the transverse opening in the pair attachment blocks to operationally connect the pair of polygonal feet to the pair of attachment blocks,
• a bridge between and connecting said two polygonal plates below the pin openings,
• wherein, each of the attachment blocks is mounted between the respective said two polygonal plates (21);
• and
• each attachment block presses against the bridge wherein the corresponding polygonal foot is moved toward the attachment block to make the junction between the belt frame and the polygonal feet steady.