Patent GB-1063827-A (GB)
Title: Method of and apparatus for controlling bobbin change in double-twist machines
IPC: D01H9/00
Filed: 1964-07-14
Abstract: In a two-for-one twisting frame, each carrier of a let-off package and its corresponding winding-on core remain associated as a group until the let-off package is fully unwound, and when, in one group, the yarn in the package is exhausted or broken, the group is automatically exchanged for another group which may be either a full let-off package and an empty core, or a carrier with a partly unwound let-off package and a partly-filled core, the yarn of which has been broken during the twisting operation and pieced.  Each working station of the frame is associated with readiness and tending stations, and the exchange is carried out by a carriage moving on rails running the length of the machine from a central point or from where it was last in operation.  The carriage is called and made operative by the failure of yarn, and moves the groups between the three stations in a rectangular course.  In Fig. 1, not shown, in the readiness position (B) is a series of groups each comprising a winding-on core or a partly-completed winding on such a core, slipped over the spindle-member of a carrier, which is of the kind described in Specification 995909 having a bearing which can be lifted out of a conical driving-socket embodying a thread plate and aperture.  The carrier is threaded-up with the yarn-end connected to the core or winding.  At the working-station (W), yarn from the carrier passes through a detector (13) to a traversing-guide (15) to be drum-wound on a core (17) which is held in a support (47) movable to the vertical for doffing.  The carriage comprises a support (141) and runs on rails (25, 31) while the movement of the changing-parts is controlled by a valve (51) set to perform a sequence of operations. When the carriage is called and the valve is set in motion by the detector, a cylinder (36) is energized to move the support forward so that a fork (42) engages the foremost group at (B).  The fork is attached to a cylinder (142) which now lifts the fork and the group to position (C) at the level of the winding station.  An expansible mandrel (43) carried by the rod of a cylinder (50) descends to grip the winding-on core (or package) at (C) and raise it.  A second mandrel (44) descends to grip and lift the now vertical winding-on package at the working station.  The support takes a further step forward, so that the fork engages the working carrier, which, as the fork is raised and moved forward again, is detached from the driving-parts and moved to the tending-station (52).  With further operation of the cylinders, the carrier and let-off package of the replacement group is deposited on the driving parts and the core (or package) on the support (47), while the thread is fitted by a guide (117) operated by a cylinder (118) into the detector.  The winding-on package from the working-station is deposited on top of the corresponding carrier which is now on a support (55), where the carrier and wind-on package are replaced by a fresh group, or the yarn-break repaired, and the support (55) released to descend under control of a cylinder (58) to the readiness-station.  When the working carrier stops, it does so in a position where the yarn aperture is in an accessible position as described in Specification 1,028,119. Each group may comprise two let-off packages supplying yarns to be doubled on one winding-core.