| 摘要 |
An arm pad includes a first layer (11), a second layer (14) securely attached to the first layer (11) and a flat spring (13) securely sandwiched between the first layer (11) and the second layer (14). There is provided with a third layer (12) sandwiched between the first layer (11) and the second layer (14). The flat spring (13) is securely mounted on top of the third layer (12) so as to provide additional force to the arm when the arm is stretching or retracting. |
