| 摘要 |
<p>A tambour or roll-top door and housing assembly is provided herein. The housing includes a pair of spaced apart tracks defining between them a path having a generally vertical first section with top and bottom parts, a generally horizontal second section near the top part of the first section, and a curved third section interconnecting the first and second sections. The tambour door has top and bottom parts, and side edges which are slidably disposed in the tracks of the housing, the door being movable along the path so defined. The door comprises a plurality of longitudinal segments, each having opposite ends which define the side edges of the door, these segments being situated side-by-side with their adjacent edges pivotally engaged in a hinge coupling with a pitch distance P between the couplings. The improvement provided a broad aspect of this invention comprises a shaft mounted in the housing and situated generally parallel to the door segments. A gear means comprising a first gear is mounted rotatably on the shaft, the gear having teeth with a circular pitch distance between the teeth corresponding to the pitch P of the door couplings, with the gear situated such that the teeth thereof each engage one door coupling successively as the door moves in the path and the gear rotates. A constant torque type spring, namely one which has the characteristics of substantially constant torque regardless of the degree of winding e.g., that known by the trade mark NEGATOR has an upper end coiled and freely rotatable about the shaft and a lower end secured to the bottom part of the door. Thus, the door is subject to an esstentially constant force generally counterbalancing the downward force due to the weight of the door regardless of the location of the door along the path.</p> |
