An apparatus, system, and method are disclosed for intermittently delivering fluid. The transmission mechanism according to the invention consists of a movable coupler which is in articulated connection with the input shaft and the output shaft so that transmission from the input shaft to the output shaft with a progressive characteristic is achieved in the range \u2212180\xb0 to +180\xb0. This is because various aberrations possessed by optical elements themselves used for convergence, aberrations possessed by other optical elements disposed on optical paths, assembly errors, and the like have undesired influence on the formation of linear illumination. The working end has a pilot tip with a first cutting portion. The two connectors are connected together back-to-back, so that the second ends face each other and the first ends are disposed at opposite ends of the connector. The actuation mechanisms may extend above the table top.