Sewing – Method of sewing – Workpiece manipulation other than straight line feeding
Reexamination Certificate
1999-07-09
2001-04-03
Nerbun, Peter (Department: 3741)
Sewing
Method of sewing
Workpiece manipulation other than straight line feeding
C112S475070, C112S470050, C112S470330, C112S002100
Reexamination Certificate
active
06209468
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to sewing machines and more particularly to a method and apparatus for sewing handles lengthwise on a strip of material, which strip of material is, for preferred embodiments, a border strip of a mattress.
BACKGROUND OF THE INVENTION
While handles may be sewn on a strip of material in a variety of applications, perhaps the most common application for such sewing is in sewing handles on the border strip of a mattress, inner spring or the like. Since such handles are used to lift heavy mattresses, they must be strong, one way of achieving such strength being to fold over the ends of the stock used for forming each handle to form a double thickness at the ends where sewing is performed. However, it is also important that the handles have an attractive appearance. The folds, in addition to providing to strength, also give a cleaner look to the ends of the handle. However, for good aesthetic appearance, the folds on both ends of each handle should be of substantially the same length, both layers of each fold should be perfectly aligned and the handle should lie substantially flat against the mattress when not in use.
Heretofore, such aesthetically pleasing handles have been achieved only by using semiautomated techniques for sewing the handles, it otherwise being difficult to compensate for skewing of fold ends, stretching of for example the border material which may prevent the handle from laying flat and various factors influencing the length of the folds. However, any machine requiring a skilled operator is more expensive to operate than a fully automated machine and semi-automated machines are also significantly slower. A fully automated machine operating under computer control can also provide greater flexibility in the jobs that can be performed and the way the jobs are performed, for example permitting borders for different sized mattresses to be handled without expensive hand readjustments of the machine.
In view of the above, it would be preferable if a machine and a method for the operation thereof could be developed which would permit the filly automated sewing of handles on mattress border stock or other suitable strips of material at relatively high speed while still achieving quality, aesthetically pleasing handles.
SUMMARY OF THE INVENTION
In accordance with the above, this invention provides a method and apparatus for automatically sewing handles lengthwise on an elongated strip of material, for example mattress border material, which includes the forming of a fold on a leading edge of a handle stock, the moving of the fold to a sewing head where the fold is sewn to the border or other strip of material, the cutting of a sufficient length of handle stock to form the handle and the forming of a fold on a trailing end of the handle at the sewing head where it is sewn to the strip of material, thereby completing the handle. The forming of each handle fold preferably includes method/apparatus facilitating the alignment of the fold.
More specifically, the apparatus includes a first handle stock feeding assembly, a second stationary sewing head assembly, a programmably controlled drive for effecting relative movement between the first and second assemblies toward and away from each other and a second programmably controlled drive for feeding the strip of material to and through the sewing head of a sewing head assembly. The first assembly includes an extending guide plate coacting with first components on the second or sewing head assembly as the first drive moves the assemblies toward each other to form a fold in the leading edge of the handle stock and deliver the fold to the sewing head where the fold is sewn to the strip of material. A cutter is also provided on the first assembly for cutting a sufficient length of the handle stock to form the handle. Finally, the extending guide plate coacts with second components on the second assembly to form a fold at the sewing head on a trailing end of the handle, the fold being sewn to the strip of material to complete the handle.
In operation, a length of handle stock sufficient to form the first fold extends beyond the end of the guide plate when the guide plate reaches the first components, the first components including a folding bar and a drive moving the bar down over the leading edge of the guide plate to fold the length of handle stock down, the guide plate passing over the bar as the first assembly continues to move toward the second assembly. This results in the bar pressing the length of handle stock against the bottom of the guide plate to form the fold. For preferred embodiments, the folding bar includes a flexible extension or drum thereover which coacts with edge projections or fingers on the guide plate to assure proper alignment for the folded over length of handle stock. The flexible drum preferably also maintains a desired tension on the handle stock. For a preferred embodiment, the sewing head also includes staking needles and a drive mechanism which moves the needles into engagement with each fold when the fold is positioned at the sewing head, removes the staking needles when the fold is clamped by the sewing head and tilts the staking needles out of the way once they have been retracted. An end detector is also provided for the handle, the guide plate coacting with the second components to form the fold on the trailing end of the handle in response to a selected output from the detector.
The second components preferably include a rear folding bar and a folding blade, the bar and blade normally being retracted to an inoperative position, and a drive being provided for moving the bar and blade to an operative position at a selected time after the fold at the leading end of the handle has been sewn to the strip of material. The second components also include a drive which moves the folding bar down past a trailing edge of the blade when only a length of the trailing end of the handle stock sufficient to form a fold extends beyond the trailing edge of the blade, the bar folding the trailing end of the handle over the trailing edge of the blade. Finally, a mechanism is provided for folding the trailing end of the handle under the blade to form the trailing end fold on the handle. For a preferred embodiment, the mechanism for folding the trailing end includes the programmably controlled drive moving the guide plate under the blade. The folding bar and/or the foot preferably include components for facilitating alignment of the fold. Alternatively, the second folding bar and the blade may be moved relative to each other so that the bar passes under the blade to fold the trailing end of the handle thereunder.
The method for sewing the handles preferably includes the steps of: (a) feeding the strip of material to and through the sewing head, such feeding being programmably controlled; (b) feeding a leading end of handle stock to extend beyond the end of the guide plate on the feed assembly by a length sufficient to form a handle fold; (c) moving a folding bar down past the tip of the guide plate to fold the extending handle stock down over the guide plate; (d) moving the feed assembly toward the sewing head with the guide plate over the fold bar to form a handle fold, this step continuing until the fold is at the sewing head; (e) using the sewing head to sew the fold on the handle stock to the strip of material; (f) cutting the handle stock at a point so as to provide sufficient handle stock to form the handle; (g) continuing step a, the handle now sewn to the strip of material moving therewith; (h) moving a second folding bar and a folding blade into a position adjacent the sewing head with the bar above the handle and adjacent the trailing edge of the blade and with the blade below the handle; (i) detecting when the cut trailing end of the handle reaches a selected position, for example, when a length of this end sufficient to form a fold extends beyond the trailing edge of the folding blade; (j) moving the second folding bar down past the trailing edge of the blade
Marcangelo Steve
Porter Michael R.
Nerbun Peter
Porter International
Wolf Greenfield & Sacks P.C.
LandOfFree
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