A sewing machine includes a needle bar turning apparatus. The apparatus includes: a needle bar holder swingably held with a fulcrum point as the center of rotation; a swing rod connected to the needle bar holder to transmit a driving force that swings the needle bar holder; a needle bar held by the needle bar holder, which is slidable along the axis and turnable with the axis as the center of rotation, and swingable together with the needle bar holder; a coupling member fixed to the needle bar such that it extends in a direction orthogonal to the needle bar; a guide shaft that extends along the needle bar; and a guide shaft connecting bracket fitted to the coupling member and the guide shaft such that it is movable relative to the coupling member in the coupling member extending direction, and turnable relative to the coupling member with a vertical line extending in the extending direction as the center of rotation.

A sewing machine includes a needle bar turning apparatus. The apparatus includes: a needle bar holder swingably held with a fulcrum point as the center of rotation; a swing rod connected to the needle bar holder to transmit a driving force that swings the needle bar holder; a needle bar held by the needle bar holder, which is slidable along the axis and turnable with the axis as the center of rotation, and swingable together with the needle bar holder; a coupling member fixed to the needle bar such that it extends in a direction orthogonal to the needle bar; a guide shaft that extends along the needle bar; and a guide shaft connecting bracket fitted to the coupling member and the guide shaft such that it is movable relative to the coupling member in the coupling member extending direction, and turnable relative to the coupling member with a vertical line extending in the extending direction as the center of rotation.

In a method for controlling sewing operation of a sewing machine, a stitch needle completes an in-and-out movement on a fabric with a first tension applied to an upper thread when the stitch needle, with respect to a fabric-feeding mechanism, is at a first relative position corresponding to a first pattern part of a predetermined stitch pattern. Afterward, the stitch needle is moved, with respect to the fabric-feeding mechanism, to a second relative position corresponding to a second pattern part of the predetermined stitch pattern, and completes an in-and-out movement on the fabric at the second relative position with a second tension, which is greater than the first tension, applied to the upper thread.

In a method for controlling sewing operation of a sewing machine, a stitch needle completes an in-and-out movement on a fabric with a first tension applied to an upper thread when the stitch needle, with respect to a fabric-feeding mechanism, is at a first relative position corresponding to a first pattern part of a predetermined stitch pattern. Afterward, the stitch needle is moved, with respect to the fabric-feeding mechanism, to a second relative position corresponding to a second pattern part of the predetermined stitch pattern, and completes an in-and-out movement on the fabric at the second relative position with a second tension, which is greater than the first tension, applied to the upper thread.

A sewing machine according to the present invention includes: an upper shaft that drives a needle and a balance; a lower shaft that drives a hook and a feed dog; an upper and lower shaft belt that synchronizes rotation of the upper shaft with rotation of the lower shaft; and an idler unit that pushes an idler into the upper and lower shaft belt to change a tension side belt length, in which the idler unit includes a transmission mechanism connected to the upper shaft or the lower shaft, and a rotating body mechanism provided with the idler and having a rotating body that rotates in synchronization with the upper shaft or the lower shaft by the transmission mechanism, and a pushing amount of the idler into the upper and lower shaft belt is changed according to rotation of the rotating body.

A sewing machine according to the present invention includes: an upper shaft that drives a needle and a balance; a lower shaft that drives a hook and a feed dog; an upper and lower shaft belt that synchronizes rotation of the upper shaft with rotation of the lower shaft; and an idler unit that pushes an idler into the upper and lower shaft belt to change a tension side belt length, in which the idler unit includes a transmission mechanism connected to the upper shaft or the lower shaft, and a rotating body mechanism provided with the idler and having a rotating body that rotates in synchronization with the upper shaft or the lower shaft by the transmission mechanism, and a pushing amount of the idler into the upper and lower shaft belt is changed according to rotation of the rotating body.

A sewing machine according to the present invention includes: an upper shaft that drives a needle and a balance; a lower shaft that drives a hook and a feed dog; an upper and lower shaft belt that synchronizes rotation of the upper shaft with rotation of the lower shaft; and an idler unit that pushes an idler into the upper and lower shaft belt to change a tension side belt length, in which the idler unit includes a transmission mechanism connected to the upper shaft or the lower shaft, and a rotating body mechanism provided with the idler and having a rotating body that rotates in synchronization with the upper shaft or the lower shaft by the transmission mechanism, and a pushing amount of the idler into the upper and lower shaft belt is changed according to rotation of the rotating body.

A sewing machine according to the present invention includes: an upper shaft that drives a needle and a balance; a lower shaft that drives a hook and a feed dog; an upper and lower shaft belt that synchronizes rotation of the upper shaft with rotation of the lower shaft; and an idler unit that pushes an idler into the upper and lower shaft belt to change a tension side belt length, in which the idler unit includes a transmission mechanism connected to the upper shaft or the lower shaft, and a rotating body mechanism provided with the idler and having a rotating body that rotates in synchronization with the upper shaft or the lower shaft by the transmission mechanism, and a pushing amount of the idler into the upper and lower shaft belt is changed according to rotation of the rotating body.

A quilting machine includes a frame sized and configured to support a sheet of fabric and a tilting sewing assembly. The tilting sewing assembly includes a needle beam defining a needle beam longitudinal axis, and a needle head attached to the needle that translates along the needle beam longitudinal axis. The assembly includes a hook beam defining a hook beam longitudinal axis disposed separate from and parallel to the needle beam longitudinal axis, and an axis of rotation parallel to the needle beam and the hook beam with the hook beam disposed between the needle beam and the hook beam. The needle head is between the needle beam and the hook beam. The tilting sewing assembly is configured to pivot about the axis of rotation with the needle beam and the hook beam translating laterally about the axis of rotation to move the needle head relative to the frame.

A quilting machine includes a frame sized and configured to support a sheet of fabric and a tilting sewing assembly. The tilting sewing assembly includes a needle beam defining a needle beam longitudinal axis, and a needle head attached to the needle that translates along the needle beam longitudinal axis. The assembly includes a hook beam defining a hook beam longitudinal axis disposed separate from and parallel to the needle beam longitudinal axis, and an axis of rotation parallel to the needle beam and the hook beam with the hook beam disposed between the needle beam and the hook beam. The needle head is between the needle beam and the hook beam. The tilting sewing assembly is configured to pivot about the axis of rotation with the needle beam and the hook beam translating laterally about the axis of rotation to move the needle head relative to the frame.