Patent ID: 8191492

Claim:
A sewing machine that sews a work cloth being moved by a user, the sewing machine comprising: a detection device that detects the work cloth; a movement calculation device that calculates a direction and a distance of movement of the work cloth as movement data when the work cloth is detected by the detection device, the movement being determined based on a location where the work cloth was previously detected by the detection device, and the movement data being in the form of two-dimensional coordinate data; a movement data storage device that stores the movement data calculated by the movement calculation device; a movement data creation device that causes the detection device to detect the work cloth for each stitch formed in sewing the work cloth, thereby causing the movement calculation device to calculate the movement data, and that stores the movement data calculated by the movement calculation device into the movement data storage device; a line segment specification device that specifies a line segment as a specified line segment based on the movement data stored in the movement data storage device; a determination device that determines whether a stitch to be formed next will overlap with an already formed stitch when the work cloth is detected by the detection device in a state where a sewing needle is above the work cloth, based on whether a line segment interconnecting a first position and a second position overlaps with the specified line segment or whether the specified line segment exists within a predetermined distance from the first position or the second position, the first position being a position on the work cloth below the sewing needle, and the second position being a most recent needle drop position; and an error control device that performs an error correction operation if it is determined by the determination device that the stitch to be formed next will overlap with the already formed stitch.