Sewing – Work manipulating – Guides
Reexamination Certificate
1999-04-06
2001-12-25
Calvert, John J. (Department: 3765)
Sewing
Work manipulating
Guides
C112S235000, C112S470310
Reexamination Certificate
active
06332414
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an improvement to a sewing machine. More particularly, the invention relates to an improvement that allows easy attachment and removal of accessories to a sewing machine that aid in the sewing operation.
2. Description of the Related Technology
The heart of the basic sewing machine is referred to herein as the “sewing mechanism”, and typically contains an upper and lower part. The upper part contains a needle, a source of thread for the needle, and a foot which acts to hold the material down. The lower part contains a flat base, a secondary source of thread called a bobbin, and a set of movable gripping teeth. In operation, the materials being sewn pass between the upper and lower parts. The materials lay on the top surface of the base, are held flat against the base by the foot, and are moved forward by the action of the teeth. Interaction between the needle and the bobbin sews the fabric together at a location directly beneath the foot. This basic process has remained relatively constant since the sewing machine was invented many years ago. However, a great many improvements have been developed which allow specialized functions to be performed. These improvements generally permit such functions to be performed automatically by the machine rather than depending on the skill of the operator to perform them. Examples of such improvements are the capability for making button holes, for sewing specific types of seams, and for sewing decorative applique designs on the material.
One area which has not benefited from such automation, however, is the attachment of elastic to predominantly non-elastic materials. For such an attachment to work properly, the elastic must be prestretched before being sewn to the material and it must remain stretched as it is being sewn. Once the elastic has been sewn and released, it returns to its normal non-stretched configuration. The result is an area of material, such as the waistband of a dress, which is normally in a “gathered” configuration but can be stretched to a larger dimension. The extra gathered fabric allows the normally non-stretchable material to effectively be stretched, while the tension in the stretched elastic provides the proper force to hold the article of clothing snugly in place.
In a typical sewing machine, the operator must manually hold the elastic in a stretched position by hand while feeding it and the fabric into the sewing mechanism. Since the operator must accurately guide the fabric and the elastic while simultaneously maintaining the proper tension on the elastic, the resulting operation is awkward and requires a great deal of skill on the part of the operator. If other materials are simultaneously being sewn into the same area, this just compounds the problem. What is needed is a device that will prestretch the elastic as it is being sewn without requiring any manual intervention by the operator.
In a related area, sewing machine operators sometimes wish to sew multiple strips of linear material, such as elastic, ribbons, strips of lace, etc., onto the same area of fabric at the same time, while accurately maintaining these strips of material in a particular configuration with respect to each other. This function requires the operator to manually guide these multiple strips and accurately maintain their proper position while simultaneously tending to the other manual operations that the operator must perform. These multiple manual operations require a great deal of skill on the part of the operator, and increase the chance for error. What is needed is a mechanism that will automatically guide various sizes of ribbon and other linear material into the sewing mechanism while accurately maintaining their proper positional orientation.
Manual skill is also needed to sew a controlled distance from a material edge or other reference line. Although various accessories have been developed to allow controlled sewing of seams, hems, and other stitching applications, these accessories are generally non-removable, or removable only by disassembling a portion of the machine. Such permanent and semipermanent attachments may be suitable for repetitive high-volume work such as that performed by a large commercial clothing manufacturer, but the difficulty or impossibility of replacing attachments makes them unsuited for low-volume work, where specialized attachments must be frequently swapped out. The related technology lacks an easily-replaceable accessory that aids the operator in controlled sewing applications.
For widespread acceptance, the aforementioned needs should be met by a device that is inexpensive and simple to use so that it will appeal to the many people who sew in their homes on their personal sewing machines. It should be attachable or removable by the operator within a few seconds with no tools and no special training. It should also be capable of being easily retrofitted onto existing sewing machines.
SUMMARY OF THE INVENTION
The invention described herein solves the aforementioned problems of the prior art through the use of a device or a family of devices that may be removably affixed to a sewing machine. These devices can be affixed and operated by persons of minimal skill and experience. In a preferred embodiment, the invention includes two parts. The first may be a mounting portion which is connected to the sewing machine, preferably either in the form of the sewing machine foot or the sewing machine shank. The second may be an accessory head which performs the desired function and is easily attached to and removed from the mounting portion.
In a preferred embodiment, the accessory head may removably attached to the foot of the sewing machine by sliding it onto an upright protrusion provided for this purpose. The foot is a ski-shaped device which rests on top of the material being sewn and holds that material down. Since the foot is in close proximity to the needle and is used to help guide material under the needle, it represents an ideal location for attachments which will further automate the sewing process. An example of a conventional foot is shown in
FIG. 2
, while one embodiment of a foot of the invention is shown in
FIG. 3. A
vertical protrusion rising from the foot may be inserted into a mating slot in an accessory head. For accessories that are not subject to appreciable upward forces during a sewing operation, the force of gravity can be sufficient to hold the accessory head in place without the need for screws, clamps, or similar fastening devices. The attachment can be made even more secure by frictional forces between the slot and protrusion. Retaining forces may also be increased by the addition of appropriate mechanisms such as a clip, spring loaded ball engaging a detent, or even a magnet. Removing the accessory may be achieved simply by lifting the accessory head off the protrusion. Although the drawings show a single thin, rectangular shape for the protrusion and slot, other shapes can also be employed, as well as multiple protrusions and mating receptacles.
Examples of an accessory head are shown in
FIGS. 4A and 4B
, which depict a guide for ribbon, elastic, or other linear-shaped material. The invention is not limited to the illustrated accessory. As can be seen, the guide has a slot that penetrates the guide from top to bottom. The elastic, ribbon or other trim material feeds into this slot, which acts to accurately hold the trim material in place before it feeds into the sewing mechanism. Since positional accuracy is important, the width of this slot should be identical to, or slightly larger than, the width of the trim material being used. Since trim material comes in various widths, a family of guides with slots of various widths can be used. It is also possible to put a mechanical adjustment on the device which allows the operator to vary the width of this slot, thus allowing the operator to accommodate various sizes of trim with a single (but more complicated) guide. As shown in
FIG. 4A
, the guide al
Tayrien Steven R.
Terranova Peter A.
Calvert John J.
Fulbright & Jaworski LLP
Patel Tejash
Wizarad Attachment Co., Inc.
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