scope:

In finding a practical solution for straight-line guidance problems, a large number of electrically, hydraulically or pneumatically powered linear guides are today available on the market for selection which in some cases offer a very complex range of functions. In certain situations, however, even (approximately) straight-line guidance of a point based on linkages represent an advantageous technical alternative to linear guides with prismatic slide elements. The guidance mechanism can be located outside the actual straight-line guidance area which means that no guide elements need to be accommodated in this area. This is especially useful with a constricted installation space and a standard commercial linear unit cannot be installed.

Linkage-type straight-line guidance mechanisms are therefore also an alternative worth trying when the application is characterized by harsh or extreme external conditions, such as, for example, with a heavily contaminated environment, exposure to sprayed water, large temperature fluctuations and impact-like loads. Linkages with four revolute joints are inexpensive to manufacture and can transmit high forces and torques. Low-friction and maintenance-free designs are possible and they typically have long service lives.

Ever since they were first used in engineering, a wider practical application of straight-line guidance mechanisms has been obstructed by certain difficulties in the precise determination of the characteristic values of straight-line guidance, in particular the quality of straight-line guidance. For a long time we had to be satisfied with design procedures for straight-line guidance mechanisms which were developed intuitively and/or empirically [10; 11]. However, now that modern computing technology is universally available their precise calculation no longer represents a problem.