| 摘要 |
<p>A control shaft extends through and is rotatable in a housing parallel to a stub shaft therein which has one end extending through one wall thereof. Within the housing are four bevel gears, one being keyed or fixed to the control shaft, a second rotatable on and relative to the control shaft, and the remaining two meshing with the first and second ones and carried on a block that is rotatable on and relative to the control shaft. The second bevel gear is keyed to the larger of a pair of meshing spur gears, such larger gear being rotatable relative to the control shaft and the smaller spur gear being fixed to the stub shaft. Respective discs are fixed on the adjacent ends of the two shafts, and articulated holding devices are operable to alternately hold and release the discs. An external arm adjacent the other end of the control shaft is coupled through the housing to the block, and such arm is reciprocally operable via an external, adjustable eccentric drive that is selectively settable for any desired angle through which the arm is to be stroked. Mechanism for alternately holding and releasing the discs is synchronized with the eccentric drive to effect holding of the stub shaft via its disc throughout one stroke of the arm to permit the control shaft to rotate, and to effect holding of the control shaft via its disc throughout the return stroke of the arm.</p> |
