| 摘要 |
<p>The door/gate panel is divided up horizontally into sections (10,11,12) hinged together. The door is raised and lifted by pulleys in the form of belts (20,25) winding onto rotary-driven drums (21,24) positioned above the door panel. Torque which counteracts the weight of the door panel is applied to the drums taking the pulleys. Two of the belts are joined to the bottom section (10). Another belt or two wind in the contrary direction to the first belts and are joined to springs (26) and or weights (27) counteracting the weight of the door panel.</p> |
