Apparatus for monitoring shuttle thread supply of a sewing machine
AssigneePfaff Industriemaschinen GmbH
InventorWalter Hager
Life of this patent
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Abstract
An arrangement for monitoring the shuttle thread reserve in a sewing machine with a lockstitch revolving shuttle and with a light-emitting diode, which sends a beam of light through openings in the bobbin housing and in the bobbin to a photodetector which triggers a switching pulse for an actuating device. To obtain maximum utilization of the residual thread, the photodetector is used at the same time as a pulse generator for a counter which controls the actuating device. The counter can be connected to a switch-off device of a drive motor for the sewing machine.
Claims5
An apparatus for monitoring a shuttle thread supply in a sewing machine with a lockstitch revolving shuttle, comprising a light-emitting diode which sends a beam of light through openings in a bobbin housing and in a bobbin of the shuttle, a photodetector for receiving light from the bobbin housing when a supply of thread on the bobbin falls to a selected amount and which thereby triggers a switching pulse for actuating means, counting means connected to the photodetector for counting to a number corresponding to the selected amount of thread on the bobbin, said counting means counting toward the number each time light is received by the photodetector, the photodetector acting as a pulse generator for said counting means, and additional actuating means connected to and controllable by the counting means when the number has been reached by said counting means.
Dependencies are inferred from the claim text.