Thread tail control apparatus and method

Information

  • Patent Grant
  • 6273013
  • Patent Number
    6,273,013
  • Date Filed
    Tuesday, March 14, 2000
    24 years ago
  • Date Issued
    Tuesday, August 14, 2001
    23 years ago
Abstract
An apparatus for removing a thread tail from a hole in a presser foot on a quilting machine. The apparatus has an orifice providing a stream of pressurized air that applies a force against a section of the thread tail extending between the needle and the hole in the presser foot. The pressurized air stream pulls the thread tail through the hole in the presser foot and gathers the thread tail on an upper side of the presser foot. In another embodiment, the present invention includes a method of automatically applying a generally transverse force to a portion of the thread tail extending between the needle and the hole in the presser foot for a duration sufficient to remove the thread tail from the hole in the presser foot.
Description




FIELD OF THE INVENTION




The present invention relates to quilting machines, and particularly to an apparatus and a method of controlling a tail of a cut thread.




BACKGROUND OF THE INVENTION




In sewing machines of various types, threads are applied and manipulated on opposite sides of a fabric to form one or more patterns of stitches. The proper formation of the stitches of each series requires the cooperative movement and precise timing of cooperating stitching elements. At the end of a stitching pattern, the thread is cut; and the relative position of the fabric and the stitching elements is changed to sew another stitching pattern. Referring to

FIG. 5

, layers of fabric


20


to be stitched are laid out on top of a needle plate


22


of a quilting machine. A needle


24


is connected to a needle drive and mounted above a presser foot


28


in a known manner. The presser foot


28


is a bowl-type presser foot which is mounted by means of a support


29


to other components of the quilting machine in a known manner. The needle


24


and thread


25


reciprocate vertically through a hole


26


in the bowl-type presser foot


28


, through the layers of fabric


20


and then through a hole


30


of the needle plate


22


, thereby forming stitching


32


within the fabric. After a pattern has been stitched, the thread


25


is cut by a known thread cutting device (not shown) normally located below the needle plate


22


. Thereafter, the relative position between the layered fabric


20


and the needle


24


, presser foot


28


and needle plate


22


is changed to position the needle


24


with respect to the start of another pattern to be stitched.




As the fabric


20


is moved with respect to the needle plate


28


as shown in phantom in

FIG. 5

, the thread tail


34


is pulled to a location between the layered fabric


20


and the presser foot


28


. When that desired relative position between the layered fabric


20


and the presser foot


28


is achieved, the stitching cycle is again initiated, and as the needle


24


passes through the fabric


20


, the thread tail


34


remains locked under the presser foot


28


. When that stitching pattern is completed and the layered fabric again moves with respect to the presser foot, the thread tail


34


hangs from the upper surface


36


of the layered fabric


20


and requires manual trimming.




Therefore, there is a need to improve the process so that the manual trimming of thread tails is not required.




SUMMARY OF INVENTION




The present invention provides a method and apparatus that substantially improves the efficiency of a process of sewing layered fabric on a quilting machine. The method and apparatus of the present invention is valuable in reducing the cost of sewing layered fabric on a quilting machine by eliminating a labor intensive and time consuming manual operation. Thus, the method an apparatus of the present invention provides a more consistent, efficient and higher quality quilting machine operation and product therefrom.




In accordance with the principles of the present invention and the described embodiments, an apparatus is provided for removing a thread tail from a hole in a presser foot on a quilting machine. The apparatus has an orifice providing a stream of pressurized air capable of applying a force against a section of the thread tail extending between the needle and the hole in the presser foot. The pressurized air stream pulls the thread tail through the hole in the presser foot and gathers the thread tail on an upper side of the presser foot. The apparatus further has a valve for turning the stream of pressurized air on and off.




In another embodiment, the present invention includes a method of automatically applying a generally transverse force to a portion of the thread tail extending between the needle and the hole in the presser foot for a duration sufficient to remove the thread tail from the hole in the presser foot.




In one aspect of the invention, the thread tail extends through the hole in the presser foot and through the layered fabric material being sewn, and the method further comprises maintaining the pressurized air stream for a duration such that all of the thread tail is pulled from the layer fabric material and through the hole in the presser foot.




Thus, the apparatus of the present invention has the advantage of eliminating the labor intensive, time consuming, and expensive manufacturing operation of manually trimming hanging thread tails from the sewn fabric. The apparatus of the present invention controls the thread tail in a manner that permits the thread tail to be sewn into the layered fabric during a further stitching operation.




Various additional advantages, objects and features of the invention will become more readily apparent to those of ordinary skill in the art upon consideration of the following detailed description of the presently preferred embodiments taken in conjunction with the accompanying drawings.











BRIEF DESCRIPTION OF DRAWINGS





FIG. 1

is a partial sectioned perspective view of a presser foot and other stitching elements of a quilting machine in accordance with the principles of the present invention.





FIG. 2

is a partial top view of the presser foot of

FIG. 1

with a thread tail beneath the presser foot.





FIG. 3

is a partial top view of the presser foot of

FIG. 1

with the thread tail removed from beneath the presser foot.





FIG. 4

is a cross-sectional view taken along line


4





4


of FIG.


3


.





FIG. 5

is a partial sectioned perspective view of a prior art presser foot and other stitching elements of a quilting machine.











DETAILED DESCRIPTION OF THE INVENTION




Referring to

FIGS. 1 and 2

, as the layered fabric


20


changes position with respect to the presser foot


28


, the thread tail


34


is captured between a lower surface


35


of the presser foot


28


and the top surface


36


of the layered fabric


20


. As previously discussed, in the absence of the invention, subsequent stitching by the needle


24


will result in the thread tail


34


hanging from the surface


36


. Thus, with each pattern stitched, the thread tail


34


must be manually trimmed and removed.




In order to eliminate the hanging thread tail


34


, the present invention utilizes an air jet from an orifice


40


at one end of a tube


42


. As shown in

FIG. 2

, the orifice


40


of the tube


42


is oriented to direct a stream of pressurized air


43


substantially diametrically across the hole


26


of the presser foot


28


. The tube


42


has a nominal inside diameter of 0.0625 inches and is made from any suitable material, for example, a malleable soft copper, brass, steel, plastic, etc. The other end of the tube


42


is connected to a valve


45


that, in turn, is fluidly connected to a source of pressurized air


47


. The operation of the valve


45


is controlled by a quilting machine control


49


as will be subsequently described. The pressurized air stream from the orifice


40


applies a sufficient force on the thread


34


to move the thread tail


34


to a location on an upper side of the presser foot


28


. The pressurized stream of air


43


is maintained for a sufficient duration to pull the full length of the thread tail


34


upward through the hole


26


of the presser foot


28


.




Referring to

FIGS. 2-4

, a baffle


46


is mounted on the presser foot


28


. The baffle


46


has an outer edge


52


with an arcuate profile that matches the circular profile of the outer peripheral edge


54


of the presser foot


28


. The baffle


46


has an inner edge


53


that is substantially linear and extends between the ends


48


,


50


of the outer edge


52


, thereby forming a substantially crescent-shaped baffle


46


. The baffle


46


is attached to the peripheral edge


54


of the presser foot


28


at the ends


48


,


50


by an appropriate process, for example, welding, brazing, etc. Thus, referring to

FIG. 4

, the arcuate edge


52


of the baffle


46


is unattached to, and forms a small gap


55


with, the peripheral edge


54


of the presser foot


28


. The gap


55


is, for example, approximately 0.030 inches. Consequently, the gap provides a path for the pressurized air stream


43


from the orifice


40


in a manner to facilitate the lifting of the thread tail above the presser foot


28


.




In the illustrated embodiment of

FIGS. 2-4

, the baffle plate is mounted on the peripheral edge


54


of the presser foot


28


such that the inner edge


53


of the baffle plate


46


forms an angle a of approximately 9° rotated counterclockwise from a first diameter


57


coincident with a centerline of the mounting bracket


29


. The tube


42


is mounted within the presser foot


28


such that the pressurized air stream is directed out of the orifice


40


at an angle β of approximately 5° rotated counterclockwise from a second diameter substantially perpendicular to the first diameter. It should be noted, however, that those angles are not critical to the operation of the invention. Normally, the pressurized air stream from the orifice


40


should be directed along a path that is approximately perpendicular to the inner edge of baffle plate


46


.




Care should also be taken that the pressurized air stream does blow the thread


25


out of the eye


23


from the needle


24


(FIG.


1


). Therefore, the pressurized air stream from the orifice


40


should be directed at the needle


24


in the same direction as the thread


25


passes through the needle. In other words, the pressurized air stream from the orifice


40


should be directed generally at the side of the eye


23


of the needle


24


that receives the thread


25


.




The baffle


46


functions to direct the pressurized air stream across the presser foot


28


in a direction moving the thread tail


34


to the interior of the presser foot


28


as shown in

FIGS. 3 and 4

. Hence, the thread tail


34


is loosely gathered on top of the presser foot


28


and is not locked between the lower surface


35


of the presser foot


28


and the upper surface


36


of the layered fabric


20


. Therefore, when stitching is again initiated, the needle


24


sews both the thread


25


and the thread tail


34


into the layered fabric


20


. Thus, the thread tail


34


is sewn into the layered fabric


20


and there is no requirement for trimming the thread tail


34


after the pattern is stitched. Referring to

FIG. 4

, normally, the orifice


40


at the end of the tube


42


is uncut in a plane having an angle φ of approximately 30° with the bottom surface


44


of the presser foot


28


.




In use, the process of capturing the thread tail


34


on the upper side of the presser foot


28


is commanded by the quilting machine control


49


and is executed in association with a trim cycle that cuts the thread


25


in a known manner. At substantially the same time that the quilting machine control


49


provides an output signal to a knife commanding the knife to cut the thread, the quilting machine control


49


provides a signal over an output


51


to a valve


45


, for example, an electrically operated solenoid valve, causing the valve


45


to switch to an open state. In the open state, the valve


45


permits the pressurized air to flow from the source


47


through the fluid path formed by the tube


42


and out the orifice


40


. A timer within the quilting machine control


49


is also started so that the valve


45


remains open for a period of time, for example, 2-5 seconds. The pressure magnitude of the pressurized air and the duration of the timer must be sufficient to allow the force of the air stream


43


on the recently cut thread tail


34


to pull the full length of the thread tail


34


through the layered cloth


20


and the hole


26


of the presser foot


28


. When the timer in the control


49


expires, the quilting machine control


49


switches the state of the signal on its output


51


, thereby switching the state of the valve


45


and terminating the flow of pressurized air from the source


47


and out the orifice


40


of the tube


42


. Therefore, when the machine starts its next stitching cycle, the cut thread tail


34


is not trapped by the presser foot, but instead, is gathered loosely on top of the presser foot


28


. And, the needle


25


sews the thread tail


34


into the layered fabric


20


, leaving no tail from the top surface


36


and only a small knot on the opposite side of the fabric.




The pressurized air stream


43


of the present invention moves the thread tail to a location in which the tail


34


is not clamped by the presser foot


28


, but is free to be sewn in the layered fabric by subsequent stitching. By maintaining such control of the thread tail, the labor-intensive, time-consuming and expensive process of having to manually trim thread tails from each of the patterns stitched is eliminated. Thus, the invention reduces the labor content, the time of manufacturing, and it presents a substantial cost savings to the manufacturer.




While the present invention has been illustrated by a description of one embodiment and while that embodiment has been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the spirit and scope of the invention will readily appear to those skilled in the art. For example, in the described embodiment, the thread tail


34


is removed from the fabric at the end of a stitching pattern and before the relative position between the layered fabric


20


and the presser foot


28


is changed. Obviously, it is easier to move the thread tail


34


to the upper side of the presser foot prior to the thread tail becoming pulled beneath the presser foot


28


. However, as will be appreciated, the thread tail may be moved at a different time in the stitching cycle, and the thread tail may be also pulled from between the lower side of the presser foot and the upper surface of the layered fabric.




Further, in the described embodiment, the presser foot


28


is shown and described as a bowl-type presser foot. As will be appreciated, the invention is applicable to other types of a presser foot, for example, a flat presser foot. Regardless of its design, the presser foot should have a size that permits the thread tail to be moved to the top of the presser foot, so that it is not subject to being trapped between a lower side of the presser foot and the fabric. In addition, while the described embodiment shows a single needle, as will be appreciated, the thread tail control of the present invention may be applied to machines having any number of needles.




In addition, the orifice


40


is described as being circular. As will be appreciated, the orifice


40


may be elliptical or any other geometric shape. Further, in the described embodiment, the orifice


40


is described as having a nominal inside diameter of 0.0625 inches. However, as will be appreciated, the orifice


40


may be smaller or larger.




The described embodiment recites specific values for the angles α, β, φ, the gap between the baffle plate outer edge


52


and the peripheral edge


54


of the presser foot


28


and the time duration of the air stream. As will be appreciated those are values that have been chosen for a presser foot of a specific design in a particular application. Depending on the size and geometry of the presser foot


28


and other application related conditions, other values for those variables may be used; and further, some experimentation with respect to those variables may be required to achieve the desired results.




The invention is particularly suitable for use on multi-needle quilting machines such as described, for example, in commonly assigned U.S. Pat. Nos. 5,154,130 and 5,544,599, hereby expressly incorporated herein by reference. The invention is also useful on single needle quilting machines as, for example, described in commonly assigned U.S. Pat. Nos. 5,650,916, 5,685,250 and 5,832,849, hereby expressly incorporated by reference herein. The thread tail control is particularly suited for use at the start of the quilting of a pattern.




Therefore, the invention in its broadest aspects is not limited to the specific detail shown and described. For example, the invention may be useful in other non-quilting sewing applications. Consequently, departures may be made from the details described herein without departing from the spirit and scope of the claims which follow.



Claims
  • 1. An apparatus for controlling a thread tail extending from a needle through a hole in a presser foot on a quilting machine, the apparatus comprising:an orifice providing a stream of pressurized air capable of applying a force against a section of the thread tail extending between the needle and the presser foot, thereby pulling the thread tail through the hole in the presser foot and gathering the thread tail on an upper side of the presser foot; a valve for turning the stream of pressurized air on and off; a source of pressurized air; an air valve fluidly coupled to the source; a fluid path extending between the valve and the orifice; and the presser foot having an outer peripheral edge and the apparatus further comprises a baffle plate extending around a portion of the outer peripheral edge.
  • 2. The apparatus of claim 1 wherein the baffle plate has an inner edge extending between two points on the peripheral edge of the presser foot.
  • 3. The apparatus of claim 2 wherein the orifice directs the stream of pressurized air in a substantially perpendicular direction toward the inner edge of the baffle plate.
  • 4. The apparatus of claim 3 wherein the presser foot has a flat bottom surface and the orifice has an opening in a plane extending upward at an angle of substantially 30° with respect to the flat bottom surface of the presser foot.
  • 5. The apparatus of claim 2 wherein the inner edge of the baffle plate is substantially transverse to the stream of pressurized air.
  • 6. The apparatus of claim 5 wherein the baffle plate has an outer edge substantially matching the peripheral edge of the presser foot.
  • 7. The apparatus of claim 6 wherein the inner edge of the baffle plate is substantially linear and intersects the outer edge at its ends.
  • 8. The apparatus of claim 7 wherein the outer edge of the baffle plate and the peripheral edge of the presser foot are arcuate in shape.
  • 9. The apparatus of claim 7 wherein the baffle plate is attached to the presser foot at the ends of the outer edge.
  • 10. The apparatus of claim 7 wherein the baffle plate is attached to the presser foot only at the ends of the outer edge.
  • 11. The apparatus of claim 10 wherein the outer peripheral edge of the presser plate and the outer edge of the baffle plate are substantially circular and the baffle plate is substantially crescent shaped.
  • 12. The apparatus of claim 11 wherein the fluid path extending between the valve and the orifice is made from a formable tubing.
  • 13. A method of controlling a tail of a top thread after quilting a pattern on a multilayered fabric on a quilting machine, trimming the top thread and repositioning the needle relative to the fabric to begin the quilting of another pattern on the fabric so as to prevent a trailing of the tail of the top thread over the face of the fabric upon the quilting of said another pattern, the method comprising:with the needle withdrawn from a hole in a pressure foot, the pressure foot raised from the fabric, and the tail of the top thread extending from the needle on the back side of the pressure foot, through the hole in the pressure foot to the fabric side of the pressure foot: directing a stream of pressurized air across the back side of the pressure foot and transversely against a section of the tail of the top thread that extends between the needle and the hole in the presser foot; maintaining the stream of pressurized air onto the section of the thread tail for a period of time sufficient to pull all of the tail of the top thread through the hole to the needle side of the pressure foot; and thereafter, terminating the stream of pressurized air onto the section of the thread tail; initiating the quilting of said another pattern on the fabric by extending the needle through the hole in the pressure foot and through the fabric with the top thread extending through the hole in the pressure foot and into the fabric and with the tail of the top thread extending generally parallel to needle from the fabric side of the pressure foot and through the hole in the pressure foot to the back side of the pressure foot; and continuing the quilting of said another pattern until the entire tail of the top thread is pulled through the hole in the pressure foot and stitched along with said another pattern to the fabric; thereby preventing the trailing of the top thread upon the quilting of said another pattern.
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4149478 Sanvito et al. Apr 1979
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4599960 Brusasca et al. Jul 1986
4599961 Brusasca et al. Jul 1986
4796552 Adamski, Jr. Jan 1989
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