A rotary hook (1) of a lockstitch sewing machine composed of at least one hook body (2) includes a cylindrical cavity (11) and a basket (6, 6b) free to rotate in the cylindrical cavity (11), a bobbin case (8, 8b) housed in the basket (6, 6b) and a bobbin (4, 4b) housed in the bobbin case (8, 8b), elements (30, 40, 50, 60, 61, 70,) suited to create a friction between the bobbin case (8, 8b) and the basket (6, 6b), so as to prevent the bobbin case (8, 8b) to move freely and to vibrate within the plays present between the bobbin case (8, 8b) and the basket (6, 6b) and to consequently reduce the noisiness created during the sewing operation.

A rotary hook (1) of a lockstitch sewing machine composed of at least one hook body (2) includes a cylindrical cavity (11) and a basket (6, 6b) free to rotate in the cylindrical cavity (11), a bobbin case (8, 8b) housed in the basket (6, 6b) and a bobbin (4, 4b) housed in the bobbin case (8, 8b), elements (30, 40, 50, 60, 61, 70,) suited to create a friction between the bobbin case (8, 8b) and the basket (6, 6b), so as to prevent the bobbin case (8, 8b) to move freely and to vibrate within the plays present between the bobbin case (8, 8b) and the basket (6, 6b) and to consequently reduce the noisiness created during the sewing operation.

Vibration reduction mechanism for a sewing machine. In one example embodiment, a vibration reduction mechanism for a sewing machine includes a rotational counterweight and a reciprocating counterweight. The rotational counterweight is configured to be coupled to a driveshaft of a sewing machine and is configured to be rotated by rotation of the driveshaft. The reciprocating counterweight is coupled to the rotational counterweight. A first portion of the reciprocating counterweight is configured to be rotated by the rotation of the rotational counterweight. A second portion of the reciprocating counterweight is configured to be substantially reciprocated along a length of a structure by the rotation of the rotational counterweight.

Vibration reduction mechanism for a sewing machine. In one example embodiment, a vibration reduction mechanism for a sewing machine includes a rotational counterweight and a reciprocating counterweight. The rotational counterweight is configured to be coupled to a driveshaft of a sewing machine and is configured to be rotated by rotation of the driveshaft. The reciprocating counterweight is coupled to the rotational counterweight. A first portion of the reciprocating counterweight is configured to be rotated by the rotation of the rotational counterweight. A second portion of the reciprocating counterweight is configured to be substantially reciprocated along a length of a structure by the rotation of the rotational counterweight.

A sewing machine comprising a sewing machine body, a needle bar, and a handlebar vibration dampener is disclosed. The sewing machine body includes a sewing machine head and a handlebar assembly coupled to the sewing machine head. The needle bar is attached to the sewing machine head and configured to linearly reciprocate relative to the sewing machine head along a needle bar axis. The handlebar vibration dampener is located between the handlebar assembly and the sewing machine head to reduce vibrations transmitted by the sewing machine head to the handlebar assembly during use of the sewing machine.

A sewing machine comprising a sewing machine body, a needle bar, and a handlebar vibration dampener is disclosed. The sewing machine body includes a sewing machine head and a handlebar assembly coupled to the sewing machine head. The needle bar is attached to the sewing machine head and configured to linearly reciprocate relative to the sewing machine head along a needle bar axis. The handlebar vibration dampener is located between the handlebar assembly and the sewing machine head to reduce vibrations transmitted by the sewing machine head to the handlebar assembly during use of the sewing machine.

A sewing machine comprising a sewing machine body, a needle bar, and a handlebar vibration dampener is disclosed. The sewing machine body includes a sewing machine head and a handlebar assembly coupled to the sewing machine head. The needle bar is attached to the sewing machine head and configured to linearly reciprocate relative to the sewing machine head along a needle bar axis. The handlebar vibration dampener is located between the handlebar assembly and the sewing machine head to reduce vibrations transmitted by the sewing machine head to the handlebar assembly during use of the sewing machine.

A sewing machine comprising a sewing machine body, a needle bar, and a handlebar vibration dampener is disclosed. The sewing machine body includes a sewing machine head and a handlebar assembly coupled to the sewing machine head. The needle bar is attached to the sewing machine head and configured to linearly reciprocate relative to the sewing machine head along a needle bar axis. The handlebar vibration dampener is located between the handlebar assembly and the sewing machine head to reduce vibrations transmitted by the sewing machine head to the handlebar assembly during use of the sewing machine.

A spar for a propeller blade comprises central structural member extending from a root to a tip of the spar. A first portion of the central structural member extends from the root of the spar and a second portion extends from the tip and adjoins the first portion. The central structural member includes a first plurality of plies of composite material on a pressure side thereof and a second plurality of plies of composite material on a suction side thereof wherein the first plurality of plies are in contact with the second plurality of plies in the second portion from a leading edge to a trailing edge thereof. A plurality of yarns extends through the central structural member in at least the second portion.

A spar for a propeller blade comprises central structural member extending from a root to a tip of the spar. A first portion of the central structural member extends from the root of the spar and a second portion extends from the tip and adjoins the first portion. The central structural member includes a first plurality of plies of composite material on a pressure side thereof and a second plurality of plies of composite material on a suction side thereof wherein the first plurality of plies are in contact with the second plurality of plies in the second portion from a leading edge to a trailing edge thereof. A plurality of yarns extends through the central structural member in at least the second portion.