| 摘要 |
The apparatus has four links pivotally coupled together. First and second links each includes a first portion having an angular portion extending therefrom at an angle of between 120-135 degrees. The first link is pivotally coupled to the angular portion of the second link; the third link is pivotally coupled to the second link at about the juncture of its angular portion and its first portion; and the fourth link is pivotally coupled to the third link and to the first link at about the juncture of its angular portion and its first portion. The first portion of the second link is employed for holding a tool or a utility device thereto. A first linear actuator is pivotally coupled to the pivotal connection between the third and fourth links and a second linear actuator is pivotally coupled to the angular portion of the first link. The first linear actuator can impart linear movement to the second link in a given direction and the second linear actuator can impart linear movement to the second link in a different direction. The two linear actuators when activated simultaneously can impart a curvilinear trajectory to the second link. The effective length of each of the first and third links between their pivotal connections is equal to R and the effective length of each of the second and fourth links between their pivotal connections is equal to r. The ratio R/r is equal to a magnitude of 3 to 7.
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