Sewing or embroidery machine
AssigneeFritz Gegauf Aktiengesellschaft Bernina-Nahmaschinenfabrik
InventorsGerard Durville, Roland Beer, Beda Steinacher, Michael Berger
Life of this patent
Estimating the term…
Abstract
To determine the thread supply on a lower-thread bobbin (17), holes (19) are arranged in the shape of a spiral in a flange (21) of the bobbin. Light from a light source (35), which is directed towards the flange (21), is reflected only by those holes (19), behind which there is no longer any thread, so that the light beams (36) reach the rear flange (22) and can be reflected therefrom and received by the light receiver (39).
Claims10
Sewing or embroidery machine (1), comprising a hook (15) that can be driven by a drive motor and with a lower-thread bobbin (17) supported rotatably in the hook (15) for holding a lower-thread supply (37), the bobbin having a spindle and annular flanges (21, 22) set on ends of the spindle, at least one of the flanges (21) is perforated with a plurality of holes (19), and a light source (35) arranged axially in front of or behind the lower-thread bobbin (17), a light receiver (39) arranged in front of or behind the lower-thread bobbin (17) for receiving light beams emitted by the light source (35), a calculating and control unit for processing received signals supplied by the light receiver (39), wherein radially outer peaks (S′) of the holes (19) in at least one of the flanges (21) of the lower-thread bobbin (17) have different distances from a rotational axis (A) of the lower-thread bobbin (17).
A method for calculating a remaining thread quantity in a sewing or embroidery machine lower thread bobbin, comprising:
- providing a sewing or embroidery machine (1), having a hook (15) that can be driven by a drive motor and with a lower-thread bobbin (17) supported rotatably in the hook (15) for holding a lower-thread supply (37), the bobbin having a spindle and annular flanges (21, 22) set on ends of the spindle, at least one of the flanges (21) is perforated with a plurality of holes (19), and a light source (35) arranged axially in front of or behind the lower-thread bobbin (17), a light receiver (39) arranged in front of or behind the lower-thread bobbin (17) for receiving light beams emitted by the light source (35), a calculating and control unit for processing received signals supplied by the light receiver (39), wherein radially outer peaks (S′) of the holes (19) in at least one of the flanges (21) of the lower-thread bobbin (17) have different distances from a rotational axis (A) of the lower-thread bobbin (17), emitting light toward the bobbin;
- detecting reflected light from the bobbin that passes through the holes that are not covered by lower bobbin thread wound on the bobbin, and is reflected back to the light receiver;
- and
- calculating a remaining quantity of the lower bobbin thread based using the calculating and control unit using a signal generated by the light detector based on the reflected light.
Dependencies are inferred from the claim text.