单层及多层平面图形放缩机构的构造方法

Construction Method of Monolayer and Multilayer Mechanisms for Scaling Planar Graphs

针对采用剪刀机构作为基本单元构造平面图形放缩机构时至少需要上下两层互相铰接的构件的缺点,提出一种只由刚性杆件和柔性铰链组成平面放缩机构的方法,可以避免十字交叉的铰接,只用一层平板材料就可加工完成。该方法的基本原理是,取任意四边形的中点构成平行四边形机构,完成平面任意四边形的放缩,然后推广到任意图形,把任意图形划分为多个三角形、四边形的组合,从而可以完成其图形的放缩。该研究为平面任意形状可展式机构的设计以及机构的惯性力平衡设计提供了一种通用性方法。

Though scissors-like atomic units can construct a planar mechanism with pantograph characteristics, it needs at least two inter-connected atomic spatial mechanisms. In order to overcome the weakness, a novel planar structure, which is constructed by rigid links and compliant joints without intercrossed connection, is proposed. The principle of the mechanism is to construct a parallelogram four-bar linkage with pantograph characteristics by using the bar midpoints of a random four-bar mechanism. Further this principle is applied to a random-bar mechanism to achieve its pantograph characteristics by dividing it into triangles and quadrangles. The proposed method presents a general solution to the design of pantograph-like random-bar mechanisms In addition, this mechanism can be used in the balance for inertia force of mechanisms.