| 摘要 |
A chest expander having a pair of actuation arms, compressed spring between the arms and an elastic force controller is provided to reduce stress concentration on spring connection part, to randomly regulate intensity of elastic force of the spring and distance between the arms by fabricating the controller on either of the arms to move one end of the spring up and down along the arm. The chest expander comprises: a pair of actuation arms(10,30) moving near or apart from each other by a pivot part(35); a compressed spring(50) that is located between the arms in an inclined direction to give elastic force to the arms in a direction for spacing the arms apart from each other by compression generated when the arms are adjacent each other; and a control part(70) that is arranged on top side of either arm to make one end of the compressed spring to move up and down along the arm as closed to an imaginary arch around the other end of the spring, thereby regulating intensity of elastic force given by the spring.
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