机构和机器原理

中文译文
机构和机器原理(中文5100字,英文3000字)
1.机构介绍：
机构的功用是作为机械作用的一个部分从一个刚体到另一个刚体传送即传递运动。
一般能用作机构基本零件的机械装置有三种类型：
1．齿轮装置。那是在回转轴之间进行接触传动的啮合构件。
2．凸轮装置。把输入构件的均匀运动转换成输出构件的非均匀运动的装置。
3．平面机构和空间机构也是能使一个点或一个刚体产生机械运动的有用装置。
运动链是一个构件系统装置即若干个刚体，它们或者彼此铰接或者互相接触，方式上是允许它们彼此间产生相对运动。如果构件中的某一构件被固定而使任何其他一个构件运动到新的位置将会引起其他各个构件也运动到确定的预期的位置上的话，该系统装置就是一个可约束的运动链。如果构件中的某一构件仍保持固定而使任一运动到达一新的位置而不会使其他各个构件运动到一个确定的预期的位置上的话，则该系统装置是一个非约束运动链。

英文原文
MECHANISMS AND MACHINE THEORY
1.Introduction to Mechanism：
The function of a mechanism is to transmit or transform motion from one rigid body to another as part of the action of a machine. There are three types of common mechanical devices that can be used as basic elements of a mechanism.

1、Gear system, in which toothed members in contact transmit motion between rotating shafts.
2、Cam system, where a uniform motion of an input member is converted into a nonuniform motion of the output member.
3、Plane and spatial linkages are also useful in creating mechanical motions for a point or rigid body.
A kinematic chain is a system of links, that is, rigid bodies , which are either jointed together or are in contact with one another in a manner that permits them to move relative to one another. If one of the links is fixed and the movement of any other link to a new position will cause each of the other links to move to definite predictable position, the system is a constrained kinematic chain. If one of the links is held fixed and the movement of any other link to a new position will not cause each of the other links to move to a definite predictable position then the system is an unconstrained kinematic chain,
A mechanism or linkage is a constrained kinematic chain, and is a mechanical device that has the purpose of transferring motion and/or force from a source to an output. A linkage consists of links (or bars), generally considered rigid, which are connected by joints, such as pin Cor revolute) or prismatic joints, to form open or closed chains (or loops). Such kinematic chains, with at least one link fixed, become  mechanisms if at least two other links remain mobility, or  structures if no mobility remains. In other words, a mechanism permits relative motion between its "rigid links"; a structure does not. Since linkages make simple mechanisms and can be designed to perform complex tasks, such as nonlinear motion and force transmission they will receive much attention in mechanism study.