| 摘要 |
<p>A door closer has a first arm (4, 14) which is pivotally attached to the door case (2), a second arm (5, 15) which is pivotally attached to the door leaf (1), the opposite ends of the two arms being pivotally connected to each other (at C), and a spring biased driving device (6, 16) which is pivotally attached partly to the door case (at E), partly to the linkage system formed by the arms (4, 5; 14, 15). According to the invention the driving device (6, 16) is pivotally attached to the second arm (5, 15) at a distance from its joint (6) on the first arm (4, 14), and its joint (E) on the door case is located between the joints (A and B respectively) of the first and second arms (4, 5; 14, 15) on the door case and the door leaf respectively, the joint (B) of the second arm (5, 15) being located closest to the hinge joint (D) of the door. In a preferred embodiment the following relation applies for the door closer: a + b > 2c + d wherein a and b is the length of the first and the second arms respectively (4, 5; 14, 15), c is the distance between the hinge joint (D) of the door and the joint (B) of the second arm (5, 15) on the door leaf (1), and d is the distance between the joint (A) of the first arm (4, 14) on the door case and the joint (B) of the second arm (5, 15) of the door leaf (1) when the door is closed, whereby the door closer provides the greatest closing force when the door is closed while at the same time its resistance to door opening decreases with increasing door opening angle.</p> |
