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US 8,757,075 B2Granted
Hook system for a sewing machine
AssigneeBENINA International AG
InventorsSeverin Brunner, Niklaus Wacker, Hans Fluckiger, Georg Janouschek, Andre Stucki
Life of this patent
Estimating the term…
Abstract
For the continuous drive of a hook of a sewing machine, two drive cams (17) alternately engage in the back of the hook. During the passing of the upper thread loop, the respective drive cam (17) on which the thread would get hung up is out of engagement. The hook is situated in a conical hook race guide and is held therein by magnets.
Claims10
A hook system for a sewing machine, comprising:
- a hook (1) that is mounted for rotation and is drivable by a hook drive in a hook race (5) of a hook race carrier (7), a bobbin case (11) for a lower thread bobbin (13) is located in the hook (1), a guide bearing (21) for a cam support (19) with at least two drive cams (17) located between the hook drive and the hook (1), the drive cams (17) are displaceably guided on the cam support (19) in the guide bearing (21) that is rotatable by a shaft (35) of the drive, and the cam support (19) is displaceable by a bolt (31) located on the shaft (35) eccentrically to an axis (A) of the shaft (35), a sliding block (29) pushed onto the bolt (31), the sliding block (29) being guided in an opening (25) in the cam support (19) for movement back and forth between two parallel guide surfaces (27), and the sliding block including opposing surfaces upon which the parallel guide surfaces act, the at least two drive cams (17) are displaceable in a radial direction in two slots (23) in the guide bearing (21), the drive cams (17) are driven via the sliding block (29) such that during a rotation of the hook (1), in a first position, each of the drive cams (17) is movably located in a respective one of two openings (15) in a back (14) of the hook (1), entering into a positive connection therewith, and at subsequent rotational positions of the hook, one of the two drive cams (17) are each in a single engagement with the hook in a respective one of the openings (15) and the other of the two drive cams is disengaged from the respective one of the openings in order to allow passage of an upper thread between the hook and the bobbin case.
A hook system for a sewing machine, comprising:
- a hook (1) that is mounted for rotation and is drivable by a hook drive in a hook race (5) of a hook race carrier (7), a bobbin case (11) for a lower thread bobbin (13) that is insertable in the hook (1), a guide bearing (21) for a cam support (19) with at least two drive cams (17) located between the hook drive and the hook (1), the at least two drive cams (17) are displaceable in a radial direction in two slots (23) in the guide bearing (21), drivable by an eccentric drive, the drive cams (17) are drivable such that during a rotation of the hook (1), in a first position, each of the drive cams (17) enters into a respective one of two openings (15) in a back (14) of the hook (1), entering into a positive connection therewith, and at subsequent rotational positions of the hook, one of the two drive cams (17) are each in a single engagement with the hook in a respective one of the openings (15) and the other of the two drive cams is disengaged from the respective one of the openings in order to allow passage of an upper thread between the hook and the bobbin case, and in the bobbin case (11) there is situated a thread-deflecting spring wire (53) having a shape of a circular arc, with a first end fixedly connected to the bobbin case (11) and a second end (55) situated to extend essentially axially to an inner peripheral wall of the bobbin case (11), and being pivotable by the lower thread (49) in a thread pull direction for at least one of an increased pull-off speed or an increased pull-off force.
A hook system for a sewing machine, comprising:
- a hook (1) that is mounted for rotation and is drivable by a hook drive in a hook race (5) of a hook race carrier (7), a bobbin case (11) for a lower thread bobbin (13) that is insertable in the hook (1), a guide bearing (21) for a cam support (19) with at least two drive cams (17) located between the hook drive and the hook (1), the at least two drive cams (17) are displaceable in a radial direction in two slots (23) in the guide bearing (21), drivable by an eccentric drive, the drive cams (17) are drivable such that during a rotation of the hook (1), in a first position, each of the drive cams (17) enters into a respective one of two openings (15) in a back (14) of the hook (1), entering into a positive connection therewith, and at subsequent rotational positions of the hook, one of the two drive cams (17) are each in a single engagement with the hook in a respective one of the openings (15) and the other of the two drive cams is disengaged from the respective one of the openings in order to allow passage of an upper thread between the hook and the bobbin case, and between the guide bearing (21) and the hook (1), at least in a region of the drive cams (17), there is a lubricating element (63) to transfer a lubricant to the drive cams (17).
Dependencies are inferred from the claim text.