机械式机构大约到19世纪末达到成熟，现在几乎所有使用的机构（自动装）在其历史上都能见到。 In addition, the mechanical institutions reached maturity by the end of nineteenth Century. Now almost all the institutions (automatic devices) can be seen in its history. （2）力作用线 (2) force action line 为了只观地表示力在机械机构中怎样传递下去的状态，将力看作犹如在构件中留动的样子，描绘在草案图的机械中。表示这个力“流动”的线，在设计考察中起着重要作用。例如：产生某种动作的机械，如果处于静态平衡，难么力作用线在整体系统中封闭。如果力线不封闭，或者该机械正题开始加速运动或者在空间分解。转动力矩的作用现也同样。 In order to see only the state of the transmission of the surface force in the mechanical mechanism, the force is regarded as if it is left in the component, depicted in the machinery of the draft map. The line that indicates the force "flow" plays an important role in design investigation. For example, a machine that produces certain action, if it's in a static equilibrium, the hard force line will be closed in the whole system. If the force line is not closed, or the mechanical topic begins to accelerate motion or decompose in space. The effect of the moment of rotation is the same. （3）平衡 (3) balance 仅对于由重力产生的力，其力线不封闭。这里，重力所产生的逆转力矩成为额外难题。机械处于静态时出现逆转的部位是机械型线  流水槽模具 景观石 检查井钢模具 保定通风管道 隔离墩模具 保定保洁公司的根本缺陷之处。不要制作头重脚轻或左右重力不能保持平衡的物体。这是应为这样的物体受到一点水平向外就会翻转的缘故。此外，把握机械的大致重量，稳心的位置也是非常重要的。特别是，如果重心水平方向位于安装地脚之外，则会失去自身平衡，是机器出现非正常状态，这一点要给以注意。 The force line is not closed only for the force generated by gravity. Here, the reverse torque generated by gravity becomes an additional problem. When machinery is in static state, the reverse part is the fundamental defect of machinery. Don't make top-heavy or gravity balance objects. This is the reason why such an object will be turned outward at a certain level. In addition, it is very important to grasp the approximate weight of machine and the location of the center of stability. In particular, if the horizontal direction of gravity is located outside the installation ground, it will lose its balance, which is the abnormal state of the machine