| 摘要 |
<p>Weight counterbalancing device for a door with a raisable shutter, the device comprising a shaft (2) controlling the winding of a shutter (1) or straps for raising a shutter, the said shaft bearing two drums (3, 4) for winding belts (7, 8) on which two counterweights (5, 6) are suspended, characterised in that the belt referred to as the long belt for suspension of a counterweight referred to as the long counterweight, having a mass M6 referred to as the long mass (6), has a length corresponding to the complete travel of the said shutter, while the belt referred to as the short belt of the other counterweight (5) referred to as the short counterweight, having a mass M5 referred to as the short mass, is shorter and is mounted on the corresponding drum (3) in such a manner as to be able to wind in both directions.
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