Sewing apparatus including an arrangement for automatically monitoring the bobbin thread, and a bobbin particularly useful in such apparatus
OwnerBar-Cochva Mardix, Yaacov Sadeh +1inventors
InventorsBar-Cochva Mardix, Yaacov Sadeh, Yaacov Makover
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Abstract
A sewing machine bobbin comprises an end wall having an outer face formed with a plurality of radially-extending strips of an optically-sensible material radiating from its center, providing sensible markings enabling the optical detection of the non-rotation of the bobbin during a sewing operation indicating a break in, or the exhaustion of, the thread wound on the bobbin.
Claims16
A sewing machine bobbin comprising a pair of end walls interconnected at their centers by an axle for receiving thread wound on the axle;
- characterized in that the outer face of one of said end walls is formed with a plurality of radially-extending strips of an optically-sensible material radiating from the center of the end wall, each of said radially-extending strips of optically-sensible material having a width in the circumferential direction which is a small fraction of its length in the radial direction, whereby said radially-extending strips provide sensible markings enabling the optical detection of the non-rotation of the bobbin during a sewing operation, thereby indicating a break in, or the exhaustion of, the thread wound on the bobbin.
Sewing apparatus comprising a sewing head including a drive therefor, a bobbin for feeding thread to the sewing head, a monitoring device sensing the rotation of the bobbin and outputting a train of pulses in response thereto, and control means receiving the output of said monitoring device and effective to automatically terminate the operation of the sewing head drive upon failure to receive the train of pulses from the monitoring device;
- characterized in that said control means includes a first time delay circuit disabling the control means from automatically terminating the operation of the sewing head drive until the elapse of a first predetermined time interval after said drive has started to drive the sewing head, and a second time delay circuit disabling the control means from automatically terminating the operation of the sewing head drive until the elapse of a second predetermined time interval after said monitoring device has ceased to output a train of pulses in response to the rotation of the bobbin.
Dependencies are inferred from the claim text.