Sewing – Stitch forming – Zigzag
Reexamination Certificate
2000-05-05
2002-12-31
Izaguine, Ismael (Department: 3765)
Sewing
Stitch forming
Zigzag
C112S320000
Reexamination Certificate
active
06499415
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a sewing machine, and more particularly to a zigzag sewing machine with a walking foot having remarkable performance with work pieces of extra thickness and reliability.
Sewing machines for both domestic and commercial use have been developed before which can be utilized with work pieces of extra thickness.
Sewing machines that straight stitch have been available for decades. Sewing machines that both straight stitch and zigzag are not as common, but have been produced for years. On most sewing machines, the presser foot simply holds the fabric down and all fabric movement is accomplished with a single, bottom feed dog. There are, however, a few machines that employ a better feeding system using a mechanical walking presser foot. The walking presser foot moves forward and back in time with the feed dog such that fabric is fed in a more consistent and aggressive manner. Sewing machines with walking feet that both straight stitch and zigzag are few and far between. However, both Pfaff Sewing Machine Company and Consew Sewing Machine Company have produced such machines. However, the Pfaff machine is designed for lightweight work and utilizes an upper foot that works behind the needle where it provides very little aid in accurately feeding heavy constructions. The Consew machine is intended for high speed industrial work and is not portable nor is it versatile. These machines are not suitable for portable work with heavy fabrics or a wide range of fabric types, thickness or finish.
Sewing machines for use in canvas work and sail making require excellent material feeding. Sail makers, tent makers and canvas workers utilized home sized straight stitch walking foot machines such as the Thompson mini walker PW301 or the Tacon 601 a home sized machine that would both straight stitch and zigzag but did not have a walking foot mechanism or larger semi-industrial machines which were not portable. Heretofore in using these machines with heavy fabrics, the use of basting tapes, staples and pins were recommended. Some improvements in the feeding of heavy fabrics could be gained by increasing the foot pressure on standard drop feed machines. However these machines do not have a walking upper foot making material feeding still inconsistent and those not capable of a zigzag stitch while satisfactory for canvas work were unsatisfactory for sail making.
It is therefore highly desirable to provide a new and improved straight stitch/zigzag portable sewing machine having a walking foot that can be utilized to sew heavy, thick fabrics with remarkable performance and reliability. It is also highly desirable to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that allows for thick, heavy fabrics to be controllably fed which will not jam because of penetration by the needle in transport. It is also highly desirable to provide a new and improved straight stitch/zigzag portable walking foot sewing machine that can be utilized to sew heavy, thick fabrics without the fabric being drawn down into the presser foot opening and jamming or contributing to skipped stitches. It is also highly desirable to provide a new and improved straight stitch/zigzag walking foot sewing machine that retards the needles impact with the fabric surface. It is also highly desirable to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that evenly feeds relatively thick material from side to side and front to back. It is also highly desirable to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that decreases needle strikes.
In 1994, Datho Manufacturing, Inc., a company which produced the Thompson mini walker PW301 machine, attempted to develop a zigzag machine. A prototype of that machine however was totally unsatisfactory, for the following reasons: the width of the zigzag stitch was very narrow about 2.5 millimeters, about half the normal zigzag stitch; the needle bar, needle plate and lower feed dog did not meet properly; the machines did not sew well utilizing thick fabric assemblies or heavy fabric; the machine would skip stitches when zigzagging; and the zigzag stitch looked more like a Z than V. In 1998, a second prototype was produced in Taiwan, this prototype appeared similar to the Datho prototype but had similar problems and did not work. These problems included skipped stitches, inability to work with thick fabrics, miss shaping of the stitch to look more like a Z than a V, and the width of the zigzag was still too narrow.
Thus, it is also highly desirable to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that provides for increased width in the zigzag stitch. It is also highly desirable to provide a new and improved portable zigzag straight stitch walking foot sewing machine that has a presser foot having a relatively high lift permitting the easy insertion and removal of fabrics of thicknesses measuring as much as {fraction (5/16)} of an inch. It is also highly desirable to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that focuses foot pressure on the needle plate when the needle is withdrawn thereby eliminating skipped stitches in heavy fabrics. It is also highly desirable to provide a portable straight stitch/zigzag walking foot sewing machine that allows sewing of complicated patterns with many twists and turns without thread jams. It is also highly desirable to provide a new and improved portable straight stitch/zigzag walking foot sewing machine in which heavy fabrics are pulled along accurately. It is also highly desirable to provide a new and improved straight stitch/zigzag walking foot sewing machine that includes a moveable bobbin thread basket. It is also highly desirable to provide a new and improved straight stitch/zigzag walking foot sewing machine that has a back stop in the stitch length lever slot to control stitch length. It is also highly desirable to provide a new and improved straight stitch/zigzag walking foot sewing machine that allows stitch length to be adjusted in a precise reproducible manner.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a new and improved straight stitch/zigzag portable sewing machine having a walking foot which can be utilized to sew heavy, thick fabrics with remarkable performance and reliability.
It is also an object of the invention to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that allows for thick, heavy fabrics to be controllably fed which will not jam because of penetration by the needle in transport.
It is also an object of the invention to provide a new and improved straight stitch/zigzag portable walking foot sewing machine that can be utilized to sew heavy, thick fabrics without the fabric being drawn down into the presser foot opening and jamming or contributing to skipped stitches.
It is also an object of the invention to provide a new and improved straight stitch/zigzag walking foot sewing machine that retards the needles impact with the fabric surface.
It is also an object of the invention to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that evenly feeds relatively thick material from side to side and front to back.
It is also an object of the invention to provide a new and improved portable straight stitch/zigzag walking foot sewing machine that decreases strikes.
It is also an object of the invention to provide a new and improved portable straight stitch/zigzag walking foot sewing that provides for increases width in the zigzag stitch.
It is also an object of the invention to provide a new and improved portable zigzag straight stitch walking foot sewing machine that has a presser foot having a relatively high lift permitting the easy insertion and removal of fabrics of thickness {fraction (5/16)} of an inch.
It is also an object of the invention to provide a new and improved por
Crisp Duane W.
Grant Matthew M.
Izaguine Ismael
Krieg Devault Lundy, LLP
Sailrite Enterprises, Inc.
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