Patent ID: 8020501

Claim:
A sewing machine, comprising: a needle bar; a sewing needle attached to a lower end of the needle bar; a needle bar driving mechanism that vertically moves the needle bar and that allows the needle bar to be stopped at a given position; a needle bar position detection mechanism that detects a vertical position of the needle bar; a bed; a needle plate provided on the bed; a presser foot that presses a workpiece cloth against the needle plate; a pressure adjustment mechanism that adjusts a pressure exerted by the presser foot; a thickness detection mechanism that detects a thickness of the workpiece cloth; a feed dog that feeds the workpiece cloth; a feed dog switching mechanism that switches the feed dog between an operative state in which the feed dog is moved above and below the needle plate and an inoperative state in which the feed dog stays below the needle plate; a controller that controls the needle bar driving mechanism, the pressure adjustment mechanism, and the feed dog switching mechanism, wherein the controller is configured to be capable of executing a pre-positioning operation including: controlling the needle bar driving mechanism, based on the thickness of the workpiece cloth detected by the thickness detection mechanism and the vertical position of the needle bar detected by the needle bar position detection mechanism, to stop the needle bar at a preset position immediately before a tip of the sewing needle pierces the workpiece cloth, controlling the pressure adjustment mechanism to adjust the pressure of the presser foot at a predetermined pressure that allows movement of the workpiece cloth, and controlling the feed dog switching mechanism to switch the feed dog to the inoperative state.