Dorina Nahmaschinen Gmbh

Patrice Kemmel

Gunter Meier

A thread monitoring device for monitoring the thread supply in a sewing machine, having a rotary hook, comprises, a hook body with a thread bobbin having thread thereon which is connected to a rotatable shaft for rotation thereby. The hook includes a stationary bobbin case which is enclosed by a hook body which has a hub portion connected to the shaft. A light source is disposed on one side of the hook and a light receiver is disposed on the opposite side. Light is transmitted by the light source through a path intercepting the thread on the bobbin so that, when the thread on the bobbin is paid out during the stitching operation, beyond a predetermined amount, the light will be transmitted to a reflective wall portion of the hook body and deflected by the wall portion to the light receiver. The light receiver is connected in a control circuit to operate a control for operating the sewing machine or for actuating an indicator to show that the thread has been used up to the predetermined amount.

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Stutensee-Friedrichstal, Germany

Patrice Kemmel