Sewing machine with thread monitor
AssigneePfaff Industriemaschinen GmbH
InventorsWalter Hager, Edgar Butzen, Gunther Denuell, Kurt Arnold
Life of this patent
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Abstract
The control circuit of a catch thread device has a counter for the main shaft of the swing machine. The counter counts the number of revolutions of the main shaft 26 during the reception of one of at least two signal intensities and is reset to its initial value when this signal intensity changes to the other signal intensity. When a predetermined maximum number of revolutions is reached, the counter emits a signal indicating a thread fault.
Claims13
A sewing machine and thread monitor arrangement, comprising a bobbin held in a shuttle body, said bobbin having signal reflecting elements for reflecting a sensor signal;
- sensor means for responding to the bobbin thread running out including means for emitting sensor signals and means for detecting changes in signals reflected by said elements of said bobbin in dependence upon the different reflection characteristics of said elements, said sensor means generating pulse signals;
- a pulse generator providing one pulse per stick forming cycle;
- counter means for receiving said pulse signals from said sensor;
- and, setting means for inputting a presetting input to said counter means defining a maximum count, generating a signal indicating a disturbance in the shuttle thread when said counter means reaches said maximum count at least one additional counting device, for interrupting said signal indicating a disturbance for a number of stitch cycles for using up a slack thread section after a sewing machine function that causes slack thread.
A sewing machine with a doublelock stitch shuttle land a thread monitor, comprising:
- a receiver means for receiving signals of varying intensity from a signal generator means, said signal generating means being connected to a thread bobbin which is set into rotation by the thread being pulled off for supplying signals of different intensities to said receiver means during rotation, and control circuit means connected to said receiver means including a first counting device for counting the revolutions of a main sewing machine shaft during the duration of the reception of signals of one intensity and which is reset to its initial value by the change of these signals to another intensity, and for generating a signal indicating thread disturbance after a preselected maximum number of revolutions has been reached without a change of signal intensity to provide a switching function, at least one additional counting device, for interrupting said switching function for a number of stitch cycles for using up a slack thread section after a sewing machine function that causes slack thread.
Dependencies are inferred from the claim text.