Wide needle swing oscillating hook system for sewing machines

In a sewing machine including a needle oscillating along a linear direction and threaded with a needle thread forming a loop, a bobbin threaded with a bobbin thread, and an oscillating hook having a hook finger engaging and moving the loop so that the loop surrounds and is pulled tight against the bobbin thread for each stitch, a drive mechanism for driving the oscillating hook, the drive mechanism including:

• a rotating driving wheel;
• a rack coupled to the driving wheel and driven transversely in simple harmonic motion between two extreme positions in response to rotation of the driving wheel;
• and
• a pinion engaging the rack, the pinion being coupled to and driving the oscillating hook and having a non-uniform radius, and the rack having a varying width where the rack engages the pinion to accommodate the non-uniform radius of the pinion, whereby, in response to a constant rotation speed of the driving wheel, the hook is oscillated at a velocity that varies with rotational position of the hook so that swing of the needle transverse to the linear direction may be increased.

In a sewing machine including a needle oscillating along a linear direction and threaded with a needle thread forming a loop, a bobbin threaded with a bobbin thread, and an oscillating hook having a hook finger engaging and moving the loop so that the loop surrounds and is pulled tight against the bobbin thread for each stitch, a drive mechanism for driving the oscillating hook, the drive mechanism including:

• a rotating driving wheel having a coaxially mounted stationary first gear and a rotating second gear eccentrically mounted on the rotating driving wheel and engaging the first gear;
• a rack coupled to the driving wheel and oscillating transversely between two extreme positions in response to rotation of the driving wheel;
• a link coupling the rack to the driving wheel, pivotally connected at a first end to the second gear and pivotally connected at a second end to the rack for driving the rack in response to rotation of the driving wheel;
• and
• a pinion engaging the rack, the pinion being coupled to and driving the oscillating hook, whereby, in response to a constant rotation speed of the driving wheel, the hook is oscillated at a rotational velocity that varies with rotational position of the hook so that swing amplitude of the needle transverse to the linear direction may be increased.

In a sewing machine including a needle oscillating along a linear direction and threaded with a needle thread forming a loop, a bobbin threaded with a bobbin thread, and an oscillating hook having a hook finger engaging and moving the loop so that the loop surrounds and is pulled tight against the bobbin thread for each stitch, a drive mechanism for driving the oscillating hook, the drive mechanism including:

• a rotating driving wheel having a coaxially mounted stationary first gear and a rotating second gear eccentrically mounted on the rotating driving wheel and engaging the first gear;
• a first rack coupled to the driving wheel and oscillating transversely between two extreme positions in response to rotation of the driving wheel;
• a first pinion engaging the first rack and including a coaxial second pinion, the first and second pinions differing in diameter;
• a second rack engaging the second pinion;
• and
• a third pinion engaging the second rack and driving the oscillating hook, whereby, in response to a constant rotation speed of the driving wheel, the hook is oscillated at a velocity that varies with rotational position of the hook so that swing of the needle transverse to the linear direction may be increased.

In a sewing machine including a needle oscillating along a linear direction and threaded with a needle thread forming a loop, a bobbin threaded with a bobbin thread, and an oscillating hook having a hook finger engaging and moving the loop so that the loop surrounds and is pulled tight against the bobbin thread for each stitch, a drive mechanism for driving the oscillating hook, the drive mechanism including:

• a rotating driving wheel;
• a rack coupled to the driving wheel and oscillating transversely between two extreme positions in response to rotation of the driving wheel;
• a slotted lever including a longitudinal slot, the slotted lever being pivotally mounted on a pivot at a first end of the slotted lever remote from the slot;
• a first link pivotally connected at a first end to the driving wheel and pivotally connected at a second end to the slotted lever;
• a second link pivotally connected at one end to the rack and including a pin at a second end, the pin being slidably disposed in the longitudinal slot of the slotted lever for sliding relative to the slotted lever in response to rotation of the driving wheel and pivoting of the slotted lever for driving the rack;
• and
• a pinion engaging the rack, the pinion being coupled to and driving the oscillating hook, whereby, in response to a constant rotation speed of the driving wheel, the hook is oscillated at a rotational velocity that varies with rotational position of the hook so that swing amplitude of the needle transverse to the linear direction may be increased.

In a sewing machine including a needle oscillating along a linear direction and threaded with a needle thread forming a loop, a bobbin threaded with a bobbin thread, and an oscillating hook having a hook finger engaging and moving the loop so that the loop surrounds and is pulled tight against the bobbin thread for each stitch, a drive mechanism for driving the oscillating hook, the drive mechanism including:

• a rotating driving wheel;
• a pivoting lever pivoted at a first end and coupled to the driving wheel;
• a first rack;
• a first pinion engaging the first rack and rotationally mounted on a pin on the pivoting lever;
• a second rack oscillating transversely between two extreme positions in response to rotation of the driving wheel;
• a link pivotally connected at one end to the first pinion and pivotally connected at a second end to the second rack;
• and
• a second pinion engaging the second rack, the second pinion being coupled to and driving the oscillating hook whereby, in response to a constant rotation speed of the driving wheel, the hook is oscillated at a velocity that varies with rotational position of the hook so that swing of the needle transverse to the linear direction may be increased.