首页>
外国专利>
Looper for lower thread in double lock stitch sewing machine has extractor with magnetic attraction to pull the bobbin and upper section of the bobbin housing clear of the lower housing section
Looper for lower thread in double lock stitch sewing machine has extractor with magnetic attraction to pull the bobbin and upper section of the bobbin housing clear of the lower housing section
The rotating looper, for a double lock stitch sewing machine, is assembled so that the axial extension of the outer end plate of the upper section of the bobbin housing is reduced to increase the available space volume for wound thread. The rotating looper, for a double lock stitch sewing machine, is assembled so that the axial extension of the outer end plate (5') of the upper section (4') of the bobbin housing is reduced to increase the available space volume for wound thread. An external extractor (6'), at least partially of ferromagnetic material, removes the upper section (4') of the bobbin housing together with the bobbin (3') from the lower section (2) of the bobbin housing. When the extractor (6') and the upper section (4') of the bobbin housing are in contact with each other, the magnetic attraction force between them is greater than the axial holding force between the upper (4') and lower (2) sections of the bobbin housing. The bobbin (3') is at least partially of a ferromagnetic material. No extraction units or thread tensioners take up any space at the outer end plate (5') of the upper section (4') of the bobbin housing. The outer end plate (5') of the upper section (4') of the bobbin housing is flat and thin at the bobbin (3'). The inner section (20') of the bobbin (3') is of ferromagnetic material, and the remainder of the bobbin is of a material which is not ferromagnetic. The bobbin (3'), the upper (4') and lower (2) sections of the bobbin housing have an axial extension. A magnetic attraction is between the upper section (4') of the bobbin housing and the bobbin (3'), and the inner section (20) of the bobbin (3') has a permanent magnetic characteristic. A permanent magnetism is maintained at the upper section (4') of the bobbin housing which is sufficient to hold the bobbin (3') in the upper housing section (4'). The extractor (6') has a permanent magnetism. A permanent magnet, pref. of rare earths, is at the bobbin shaft of the upper section of the bobbin housing, which is in contact with the extractor (6') for removal. The upper section (4') of the bobbin housing has at least one spring arm, and the lower section (2) of the housing has at least one recess (16) to be engaged by the spring arm in a ratchet lock action, when the upper section (4') is inserted into the lower section (2) of the bobbin housing, to give a force-fit bond in the axial direction between the two housing sections (2,4').
展开▼
