| 摘要 |
The seesaw has a board (1) which pivots vertically on a horizontal axle (2) mounted on ball bearings. It pivots horizontally on a vertical axle (7) in its support which turns in ball bearings. The board has telescopic arms which are graduated in 5 kg steps so that two users are balanced.At each end of the arms there are handlebars (8) which are joined to a pinion (13). A chain (12) round this passes round another pinion which is joined to a counterweight (9), which is moved to make the seesaw go up or down. The board is equipped with shock absorbers (3) at each end. It also has a wheel which avoids lateral thrusts which are similar to the making of contact of aircraft landing gear with ground.
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