| 摘要 |
<p>On the shaft 6 for driving the movement of the panel 1 of the door is fixed a sprocket 8 over which there runs a chain 11, one end 12 of which is fixed and the other end of which is weighted by a bobweight 14. The chain 11 passes over a toothed pulley 9, the case (cheek, frame, shell) of which is carried by a support 10. From this support 10 are suspended weights 16 and to this support is fastened the upper end of a tension spring 23, the lower end of which is fixed to the ground by a chain 25. In the up position of the panel 1, the support 10 is in the down position and balances the weight of the panel 1, the spring 23 being substantially unstretched. When the panel closes, exerting an increasing force, the support 10 rises and the spring 23 is stretched, giving continuous balancing. The invention applies to heavy doors, such as the doors of carparks or garages. <IMAGE></p> |
