『壹』 求助！机械工程专业英语翻译，急！！
1. The four-bar linkage may take form of a so-called crank-rocker or a double-rocker or a double-crank (drag-link) linkage, depending on the range of motion of the two links connected to the ground link. The input crank of a crank-rocker type can rotate continuously through 360, while the output link just "rocks" (or oscillates). As a particular case, in a parallelogram linkage, where the length of the input link equals that of the output link and the lengths of the coupler and the ground link are also the same, both the input and output link may rotate entirely around or switch into a crossed configuration called an antiparallelogram linkage. [1] Grashof's criteria states that the sum of the shortest and longest links of a planar four-bar linkage cannot be greater than the sum of the remaining two links if there is to be continuous relative rotation between any two links.
2. Besides having knowledge of the extent of the rotations of the links, it would be useful to have a measure of how well a mechanism might "run" before actually building it. Hartenberg mentions that "run" is a term that means effectiveness with which motion is imparted to the output link; it implies smooth operation, in which a maximum force component is available to proce a force or torque in an output member. Although the resulting output force or torque is not only a function of the geometry of the linkage, but is generally the result of dynamic or inertia force, which are often several times as large as the static force. For the analysis of low-speed operations or for an easily obtainable index of how any mechanism might run, the concept of the transmission angle is extremely useful. During the motion of a mechanism, the transmission angle changes in value. A transmission angle of 0 degree may occur at a specific position, on which the output link will not move regardless of how large a force is applied to the input link. In fact, e to friction in the joints, the general rule of thumb, is to design mechanisms with transmission angle of larger than a specified value. Matrix-based definitions have been developed which measure the ability of a linkage to transmit motion. The value of a determinant (which contains derivatives of output motion variables with respect to an input motion variable for a given linkage geometry[2] ) is a measure of the movability of the linkage in a particular position.
1 。在四连杆机构的形式可以采取所谓的曲柄摇杆或双摇杆或双曲柄（拖放链接）联系，取决于各种运动的两个链接连接到地面的联系。输入曲柄的曲柄摇杆式可旋转不断通过360 ，而输出链接“岩石” （或振荡） 。作为一个特殊情况，在一个平行四边形的联系，在那里的长度等于投入的联系，在输出的联系和长度，耦合器和地面的联系也相同，都输入和输出的联系完全可以左右转动或切换成一个越过配置称为antiparallelogram联系。 [ 1 ]格拉斯霍夫的标准规定的总和最长和最短的联系，平面四连杆机构不能加一大于二剩下的两个环节，这样才能不断相对旋转任意两个之间的联系。
2 。除了知识的程度轮换的联系，这将是有益的措施以及如何可能的机制“运行”建设之前，实际上它。 Hartenberg提到， “运行”是一个术语，是指有效地传授运动的输出环节;这意味着顺利运作，其中最大力量的组成部分提供给生产武力或转矩输出成员。虽然由此产生的输出力或力矩不仅是一个函数的几何的联系，但通常是由于动态或惯性力，这往往是几次大的静力。分析的低速业务或容易获得的一个指数如何运行机制可能，概念的传动角是极为有益的。在运动的机制，传动角的变化值。传输角度0度，可能会发生在某一特定的位置，而输出的联系将不会不管多么大的力量适用于输入链接。事实上，由于摩擦的关节，一般的经验法则，是设计与传输机制的角度大于某一特定值。矩阵为基础的定义，已经制定的措施的能力联系转交议案。价值的一个决定因素（其中包含衍生品的输出变量的议案方面投入的议案变量对某一连锁几何[ 2 ] ）是衡量的可移动的联系在一个特定的立场。