Sewing machine

Patent metadata

Field	Value
Publication number	US-9605366-B2
Application number	US-201414556836-A
Country	US
Kind code	B2
Filing date	Dec 1, 2014
Priority date	Jun 6, 2014
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A sewing machine includes an upper shaft rotatable so as to drive a needle bar, a lower shaft rotatable so as to drive a hook, an upper-shaft pulley attached to the upper shaft, a lower-shaft pulley attached to the lower shaft, a belt linking the upper-shaft pulley and the lower-shaft pulley, and synchronizing a rotation of the upper-shaft pulley and a rotation of the lower-shaft pulley with each other, a belt adjusting mechanism contacting the belt and changing a belt length at a tensioned side at which the belt is drawn, and a tensioner tensioning the belt in accordance with the change in the belt length of the belt at the tensioned side.

First claim

What is claimed is:

1. A sewing machine comprising:
an upper shaft rotatable so as to drive a needle bar;
a lower shaft rotatable so as to drive a hook;
an upper-shaft pulley attached to the upper shaft;
a lower-shaft pulley attached to the lower shaft;
a belt linking the upper-shaft pulley and the lower-shaft pulley, and synchronizing a rotation of the upper-shaft pulley and a rotation of the lower-shaft pulley with each other;
a belt adjusting mechanism contacting the belt and absorbing slack at a tensioned side at which the belt is drawn by moving in or away from a direction in which the belt adjusting mechanism pushes the tensioned side; and
a tensioner tensioning the belt in accordance with an absorbing level of the slack of the belt;
wherein the tensioner comprises;
a tension adjusting idler contacting the belt at the loosened side where the belt is drawn out; and
an elastic member connecting to the tension adjusting idler.

2. The sewing machine according to claim 1 , wherein the belt adjusting mechanism:
comprises at least one idler contacting the tensioned side; and
changes the absorbing level of the slack of the belt at the tensioned side by causing the idler to swing.

3. The sewing machine according to claim 1 , further comprising a restrictor restricting a movable range of the tensioner when a tensioned condition of the belt exceeds pushing force by the tensioner.

4. The sewing machine according to claim 3 , wherein:
the restrictor comprises a stopper arm and a stopper disposed with a predetermined distance from the stopper arm; and
the stopper arm contacts with the stopper to restrict the movable range of the tensioner when the tensioned condition of the belt exceeds the pushing force by the tensioner.

Assignees

• Janome Sewing Machine Co Ltd

Inventors

• Koike Mikio
• Mafune Jun

Classifications

• D05B3/02 Primary

  with mechanisms for needle-bar movement · CPC title

• D05B57/34

  in overedge-stitch sewing machines · CPC title

• D05B57/36

  in lock-stitch sewing machines · CPC title

• D05B57/32 Primary

  in chain-stitch sewing machines · CPC title

• D05B69/12

  using rotary electric motors · CPC title