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US 5,211,121 AGranted
Device for detecting remainder of bobbin thread in sewing machine
AssigneeBrother Kogyo Kabushiki Kaisha
InventorYasuo Sakakibara
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AssigneeBrother Kogyo Kabushiki Kaisha
InventorYasuo Sakakibara
Estimating the term…
A bobbin thread remainder detecting device for detecting an amount of remainder of a bobbin thread wound up around a bobbin for a sewing machine, in which a winding leading end portion of the bobbin in a winding direction reverse to a winding direction of another portion of the bobbin thread, comprises a bobbin rotating direction detecting unit, including light emitting and receiving elements, disposed in a vicinity of a bobbin case for detecting a rotating direction of the bobbin and a bobbin thread remainder detecting unit, including an electronic control circuit element, disposed in association with the rotating direction detecting unit for detecting the amount of the remainder of the bobbin thread in response to rotation of the bobbin in a particular direction as detected by the rotating detecting unit. The bobbin thread remainder detecting unit detects reducing the bobbin thread remainder wound up around the bobbin at a time when the rotating direction of the bobbin changes.
A device for detecting an amount of remaining bobbin thread wound up around a bobbin which is rotatably mounted on to a shaft member of a bobbin case of a sewing machine provided with a bed comprising:
A sewing machine including a bed, a reciprocable needle and a rotating hook assembly disposed in the bed, said sewing machine comprising:
A sewing machine according to 15, wherein said detecting means comprises a pair of light emitting elements for emitting lights towards said display plate, a pair of light receiving elements for receiving lights reflected by said display plate and for generating detecting signals representing intensity of lights received by said light receiving elements, and an electronic control circuit unit for processing the detecting signals generated by said light receiving elements in such a manner that outputs of the detected signals are compared with each other and that change of the rotating direction is discriminated when the magnitudes of their outputs of the detected signals are reversed thereby to discriminate that the amount of the remainder of the bobbin thread becomes less than the predetermined length.
A sewing machine according 16, wherein said determining means further comprises an alarm means connected to said electronic control circuit unit and adapted to generate an alarm at a time when the length of the remainder of the bobbin thread becomes less than the predetermined amount.
Dependencies are inferred from the claim text.