| 摘要 |
A device to be inserted between a loom and its shed-forming mechanism to permit of rotating the latter backward or forward independently of the loom when required and thereafter to resume normal weaving with proper timing of the mechanism with respect to the loom, comprises a rotating member connected with the loom so as to effect one revolution for each pick thereof, a single-tooth clutch to connect this member with a main shaft connected with the shed-forming mechanism, during normal weaving, and coupling means to connect the said main shaft with a gearing adapted to rotate this shaft by successive complete revolutions. These coupling means include a first element rigidly carried by the said shaft, and a second element which may be engaged with or disengaged from the first one. The gearing comprises a driving gear wheel having a toothed sector and a smooth blocking sector, and a corresponding pinion having a toothed sector and a concave depression to receive the smooth blocking sector. The pinion is affixed to the second element of the coupling means, while the gear wheel is carried by an auxiliary driving shaft connected with an appropriate auxiliary motor, and this shaft carries cams adapted to control the single tooth clutch and the coupling means. When the auxiliary motor is started, during a first step the second element of the coupling means is blocked by the smooth sector and the cams disconnect the main shaft from the rotating member and connect it with the second element of the coupling means. During a second step the toothed sectors cooperate to rotate the main shaft through one revolution. Then during a third and last step, the smooth sector again blocks the pinion and the second element of the coupling means, while the cams reestablish the initial connections.
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