Back to results
US 4,805,276 AGranted
Monitoring device for double threads in warp tying machines
AssigneeZellweger Uster AG
InventorMartin Plaschy
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeZellweger Uster AG
InventorMartin Plaschy
Estimating the term…
A tying machine includes a tying device, grippers for two groups of warp threads (K.sub.a, K.sub.n) which are to be tied together and a device for separating the outermost warp thread of each group and moving it out of the plane of the warp. In the region between the separating device and a gripper, the warp threads are guided over a thread guide where the outermost warp thread is deflected and moved out of the plane of the warp. A measuring device for measuring the force exerted by a deflected warp thread on the point of deflection or on the separating device is arranged in the region of deflection, and the signal of this measuring device serves as criterion for the presence of a double thread. The measuring device may be a piezoelectric pressure convertor or an elongation measuring strip or a piezo sensor which is sensitive to deflection. Thus, the measuring device is virtually unaffected by dirt or dust. Since the signal produced by a double thread is twice as great as that produced by a single thread, such double threads are reliably recognized.
In a tying machine for tying individual threads of a first warp sheet to correspondingly positioned individual threads of a second warp sheet, said machine being of the type in which threads from at least an edge portion of a warp sheet are gripped at zones spaced apart from each other in the lengthwise direction of the threads and in which individual threads at the outermost edge of said warp sheet are successively engaged by separating means on successive cycles of machine operation to deflect them one by one out of the plane of such warp sheet, said machine having grippers, means to feed separated threads to the tying machine, guides for the separated threads, there being a separating means, feed means, guide, and gripper for each of the two warp sheets, the improvement which comprises fault detecting means for each warp sheet for sensing a value related to the magnitude of the force exerted by said separating means in each of its thread deflecting operations and for producing an error signal when the sensed value does not correspond to the approximate force required for deflecting a single thread, and when the sensed value corresponds to the approximate force required for deflecting multiple threads, the fault detecting means being positioned in the tying machine relative to the warp sheet such that the force exerted by each outermost thread of the warp sheet is successively sensed.
Apparatus for monitoring a warp tying operation to detect the presence of double threads comprising:
Dependencies are inferred from the claim text.