US3698336A

US3698336A - Device for tacking down the free end of a thread chain

Info

Publication number: US3698336A
Application number: US102295A
Authority: US
Inventors: Wilbur A Launer
Original assignee: Union Special Machine Co
Current assignee: Union Special Machine Co
Priority date: 1970-12-29
Filing date: 1970-12-29
Publication date: 1972-10-17
Anticipated expiration: 1989-10-17
Also published as: GB1369261A

Abstract

This disclosure relates to an attachment for a sewing machine for automatically picking up the loose end of a thread chain and folding the same back under the presser foot against the direction of feed, in which position the thread chain is automatically sewn down during the formation of stitching in the next workpiece. The attachment is automatic in operation with the operation thereof timed so as to make certain that the thread chain is folded back in position when the next work is presented to the sewing machine so that the thread chain is tacked down from the first stitch implanted in the next work.

Description

United States Patent Launer DEVICE FOR TACKING DOWN THE FREE END OF A THREAD CHAIN Inventor: Wilbur A. Launer, West Camp,

Union Special Machine Company, Chicago, Ill.

Filed: Dec. 29, 1970 Appl. No.: 102,295

Assignee:

References Cited UNITED STATES PATENTS Southwell et al. ..1 12/252 [451 Oct. 17,1972

3,490,403 ill 970 Boucraut ..1 12/252 Primary Examiner-James R. Boler Attorney-Diner, Brown, Ramik & Holt [57] ABSTRACT This disclosure relates to an attachment for a sewing machine for automatically picking up the loose end of a thread chain and folding the same back under the presser foot against the direction of feed, in which position the thread chain is automatically sewn down during the formation of stitching in the next work piece. The attachment is automatic in operation with the operation thereof timed so as to make certain that the thread chain is folded back in position when the next work is presented to the sewing machine so that the thread chain is tacked down from the first stitch implanted in the next work.

18 Claims, 10 Drawing Figures PATENTEnnm 11 m2 SHEET 1 [IF 3 \NVENTDR WILBUR A. LRUNER QTTUENEYS PATENTEUHET 1 I9 3.698.336 SHEET 2 OF 3 INVENTUR LU\LBUR R. LRUNER m TOQNEYS PATENTEDnm 11. I972 3, 5 35 sum 3 OF 3 INVENTOR UMLBUR A. LAUNER ATTORNEYS DEVICE FOR TACKING DOWN THE FREE END OF A THREAD CHAIN This invention relates in general to new and useful improvements in attachments for sewing machines, and more particularly to a novel attachment for picking up a loose end of a thread chain and folding the same back under the presser foot against the direction of feed so that the thread chain may be in a position to be sewn into the seam of the next work thereby imparting to the finished seam not only a reliable closure, but also a very neat appearance.

BACKGROUND OF THE INVENTION Attachments have been developed in the past by others for picking up and folding back the thread chain. These patents include US. Pat. No. 2,756,704 to Lawber; US. Pat. No. 2,854,937 to Palumbo; U.S. Pat. No. 3,356,054 to Southwell, et al.; and US. Pat. No. 3,490,403 to Boucraut. In the Lawber and Palumbo at tachments no automatic means are provided for picking up and folding back the thread chain. Although these patents did have the early concept of positioning the thread chain so that it may be incorporated in the seam of the next work.

The Southwell, et al. attachment provided a suction thread chain pick up which would automatically retrieve the thread chain and move it into position to be sewn into the seam of the following work. However, the thread chain pick-up device swings in an arc and does not with certainty assure the positioning of the thread chain in alignment with the stitching to be formed on the next work.

Boucraut proposes a simple automatic means for retrieving the thread chain in the form of an air nozzle for blowing the thread chain rearwardly and the suction pick up for receiving the thread chain. However, there is no assurance that the thread chain will always be directed by the air nozzle into the suction pick up.

SUMMARY OF THE INVENTION In view of the foregoing, it is a primary feature of this invention to provide a sewing machine attachment which will, with certainty, operate to pick up a thread chain and move it into a position to be incorporated in the seam of a next work to be sewn and wherein the attachment is simple in construction, quick and reliable in operation and can be produced and installed at minimum cost. a

In accordance with this invention, pick up of the thread chain and alignment thereof with the stitching to be formed on the next work is effected by a pick up tube which is mounted for swinging movement in a manner to move the pickup end thereof in a plane passing through the sewing machine needle and in the direction of work feed.

Another feature of the invention is the simplicity of mounting of the pick up tube and an associated motor unit to move the pick up tube to a thread chain pick up position and automatically returning the same to a retracted position for paying out the picked up thread chain.

In accordance with this invention, the pick up tube is mounted for swinging movement about a horizontal axis and the swinging thereof is effected by an air motor which includes a piston of sufficient weight so as to, in the inoperative condition of the air motor, automati cally return the pick up tube to its retracted position in which position the pick up tube holds a thread chain in alignment with a new seam to be sewn.

A further feature of the invention is the controlling of the actuation of the thread chain cutter in accordance with the position of the thread tube whereby the thread chain is out only when the pick up tube is in a position to pick up the thread chain, thereby assuring alignment of the thread chain with the pick up tube, which, in turn, assures the picking up of the thread chain.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

IN THE DRAWINGS:

FIG. 1 is a plan view of a sewing machine equipped with the attachment of this invention.

FIG. 2 is a schematic pneumatic and electrical diagram of the controls of the apparatus.

FIG. 3 is a rear elevational view of the sewing machine and attachment of FIG. 1.

FIG. 4 is a left elevational view.

FIG. 5 is a fragmentary vertical sectional view taken along the line 5-5 of FIG. 3 and shows the drive for swinging the pick up tube.

FIG. 6 is an enlarged fragmentary front elevational view of the sewing machine and attachment and shows specifically the details of the attachment.

FIG. 7 is a fragmentary end elevational view similar to FIG. 4 and shows the pick up tube immediately after it has picked up the chain thread.

FIG. 8 is an enlargement of a portion of the apparatus of FIG. 7 and shows further the details of the picking up of the thread chain.

FIG. 9 is an enlarged fragmentary transverse vertical sectional view taken through the end portion of the pick up tube and a cooperating member showing the manner in which the thread chain is releaseably retained within the pick up tube.

FIG. 10 is a fragmentary plan view of typical work showing the manner in which a thread chain is stitched into a retained position. I

It is to be understood that the attachment of this invention is not restricted to use in conjunction with any specific sewing machine. However, for convenience of description, the attachment, which is generally identified by the numeral 15, is illustrated as being mounted on and in cooperation with a sewing machine which is generally identified by the numeral 16, the sewing machine being of the general type disclosed in U.S. Pat. No. 2,704,042 to Wallenberg, granted on Mar. 15, l955.

As is clearly illustrated in FIGS. 1 and 6, the attachment 15 includes a bracket plate 17 which is secured to and in overlying relation with respect to a top cover 18 of the sewing machine 16. The bracket plate 17 is spaced from the top cover 18 by means of sleeve-like spacers 20 and is secured in place by means of bolts 21 passing down through the plate 17 and the spacers 20 and threaded into the top cover 18.

A hearing block 22 is secured on the bracket plate 17 by means of fasteners 23 and has a tubular shaft 24 extending therethrough. The tubular shaft 24 is rigidly retained in the bearing block 22 by means of set screws 25.

It is to be noted that the tubular shaft 24 projects outwardly from the bearing block 22 in both directions and the right hand end of the shaft 24, as viewed in FIG. 6, is connected to a lint filter 26. The lint filter 26 is provided with an air flow adjusting valve 27 of a conventional type. Piping 28 extends from the valve 27 and, as is shown in FIG. 2, is connected to a manifold 30. Coupled to the mainfold 30 is an air hose 31 which has incorporated therein a further air flow regulator 32. The air hose 31 is, in turn, connected to a vacuum pump 33.

The other end portion of the tubular shaft 24 extends into overlying relation with respect to the overhanging arm 34 of the sewing machine 16. A sleeve 35 is rotatably received on this shaft portion and has a free end which abuts the bearing block 22. The other end of the sleeve 35 is rigidly connected, preferably integrally, by welding, with a hollow member 36 having the shape of a narrow horizontally disposed cylinder. This cylinder member carries a length of tube which will hereinafter be referred to as a pick up tube 37. The tube 37 extends substantially radially of the cylinder member 36 and projects downwardly in a direction towards the cloth plate 38 of the sewing machine. The tube 37 is of an L-shaped configuration and includes a horizontal portion 40 which which extends substantially in pa'rallellism with the cloth plate 38.

At its free end, the horizontal portion 40 of the tube 37 is formed with a restricted opening 41 which may be considered the nozzle of the pick up tube 37. The opening 41 is so positioned that, upon oscillation of the sleeve 35, the cylinder member 36 and the pick up tube, which members will hereinafter be referred to as a transfer assembly 42, the opening will move in the line of work feed for the sewing machine 16 and in the vertical plane of needle movement. In other words, the path of movement of the opening 41 extends directly along the line of stitching of the sewing machine.

Oscillatory movement is imparted to the transfer assembly 42 to swing the pick up tube 37 from a retracted position to a thread chain pick up position and return bya vacuum actuated motor 43, as is best shown in FIGS. and 6. The motor 43 includes a cylinder 44 and a piston 45 which, in the retracted position of the pick up tube 37 is disposed in a lowermost position.

The cylinder 44 is vertically disposed and is supported by a bracket 46 by means of a strap 47. The bracket 46 is, in turn, mounted on top of the bearing block 22.

The piston rod type link member 48 is pivotally connected at one of its ends with the piston 45 and is provided at the opposite end thereof with an enlarged bifurcated portion which is pivotally connected to a crank member 50 by means of a pin 51. The crank member 50, in turn, is rigidly secured to and extends transversely from the sleeve 35. It is also to be noted that an angle plate 52, which is rigidly secured to the support plate 17, is provided to prevent axial movement of the sleeve 35 on the tubular shaft 24. The angle bracket 52 has an upright portion which is provided with a semi-circular cutout partially encompassing the sleeve 35, as is clearly shown in FIG. 5.

The upper end of the cylinder 44 is closed while the bottom end thereof is open. The closed up end of the cylinder 44 is provided with a fitting 53 which, as is best shown in FIG. 2, is connected to an air conduit 54 leading from a conventional three way solenoid control valve 55. A conduit 56 leads from the valve 55 to the manifold 30 which, as previously set forth, is connected to a vacuum pump 33 by way of the air flow regulator 32.

When the valve 55 is actuated, suction force is applied to the upper end of the cylinder 44, drawing the piston 45 upwardly into the cylinder. As the piston 45 moves upwardly, it pulls the lever 50 upwardly to rotate the sleeve 35 in a clockwise direction, as viewed in FIG 5. Rotation of the sleeve 35 will, of course, result in a like rotation of the transfer assembly 42.

Termination of the application of a suction force to the upper end of the piston 45 will allow gravity to take over and the piston 45 will slide back down in the cylinder 44. In order to expedite this reverse movement of the piston, the link type piston rod 48 is of a heavy construction so as to enhance the effect of gravity.

In order to further facilitate the downward movement of the piston 45, there is provided either in the top end of the cylinder 44 or in the fitting 53, as is shown in FIG. 6, a vent hole 57 which serves to more quickly restore atmospheric pressure in the upper part of the cylinder 44 and within the conduit 54. Venting of the upper end of the cylinder will contribute to a rather quick return of the piston 45 to its downward position. Thus, once the suction force is cut off, the transfer assembly 42 will be rotated back, in a counterclockwise direction in a very rapid manner.

Referring once again to FIG. 2, it will be seen that the operation of the control valve 55 is controlled by a switch 60. The switch 60 is a conventional delay switch of the type that stays closed for a predetermined period of time, and upon a lapse of this period, opens automatically. The switch 60 is arranged in series with a coil 59 of the solenoid control valve 55 with the normal position of the valve 55 being one disconnecting the conduit 56 from the conduit 54. The switch 60 is preferably located so that it will be actuated when the presser foot lifting means of the sewing machine 16 are actuated. To this end, the switch 60 may be mounted in suitable proximity to the feed lift lever 61 of the sewing machine, as is illustrated in FIG. 3. It is to be understood that the switch 60 may be secured directly to the sewing machine 16 or to a bracket arranged in a suitable location. The switch 60 is provided with an actuating arm 62 which carries a follower 63 which may be engaged by the feed lift lever 61.

Referring once again to FIG. 2, it will be seen that the electrical circuit includes terminals 64 and 65 of a suitable source of electrical power. Arranged in series in the electrical circuit is a manually operable main switch 66 which, in when closed, provides for the automatic operation of the vacuum pump 33. The circuit also includes a pilot light 67 for indicating the on condition of the circuit.

It is also to be noted that the electrical circuitry includes a further switch 68 which controls the energization of a solenoid 70 which, in turn, controls the operation of a thread chain cutter 71. With particular reference to FIG. 3, it will be seen that the solenoid 70 is illustrated as being mounted on the sewing machine 16 by means of a bracket 72 with the solenoid 70 being mechanically connected to the thread chain cutter 71 by means of suitable linkage 73. It is to be understood that the linkage may be of any desired construction and the specific details thereof are not set forth here inasmuch as in of itself, the linkage forms no part of this invention. It is also to be noted from FIG. 4 that the thread chain cutter 71 is in the form of a movable knife which cooperates with a fixed knife 74.

Referring now to FIG. 4 in particular, it will be seen that the switch 68 is mounted in the proximity of the cylinder member 36 by way of a support bracket 75 which, in turn, is suitably secured to the support plate 17. Further details of the mounting of the switch 68 and the support bracket 75 are found in FIG. 6. It is to be noted that the switch 68 includes an actuator 76 which carries a cam follower 77. Further, it is to be noted that the cylindrical member 36 is provided with a cam 78 with which the cam follower 77 is aligned and which cam 78 is operable, upon rotation of the transfer assembly 42 to the thread chain pick up position to move the actuator 76 to a position closing the switch 26 and completing the circuit to the chain cutter solenoid 70.

It is also to be noted that the attachment includes a member 80 which cooperates with the pick up tube 37 and more particularly to the opening 41 therein to restrict the movement of a thread chain out of the pick up tube. The member 80 is preferably in the form of a small sheet of flexible plastic or like material and is so arranged on a bracket 81 secured to the sewing machine 16 that it will substantially cover the suction opening 41 when the pick up tube 37 is in its fully retracted position as is shown in FIG. 9. The relationship between the member 80 and the nozzle or opening 41 is such that it will increase the suction force in the pick up tube and also will apply a limited amount of friction on the thread chain, which thread chain is identified by the numeral 82, when the thread chain is being drawn out of the tube portion 40 by an advancing work.

OPERATION It is to be understood that the sewing machine 16 will operate in a conventional manner with work being fed therethrough to produce desired stitching, such as stitching 83 illustrated with respect to work W in FIG. 10. After the desired stitching has been formed, the work will pass out from beneath the presser foot 84 and the sewing machine will continue to operate for a limited period of time forming the thread chain 82. Thereafter, the sewing operation of the sewing machine 16 will be discontinued, either manually or automatically, and the feed lift lever 61 will be actuated to elevate the presser foot 84. At this time, the actuating arm 62 of switch 60 will be moved to a circuit closing position to initiate the cutting of thread chain, the retrieving of the loose end of the thread chain, and the movement of thread chain to a position where it will automatically be tacked beneath the stitching 83 of a following work during the sewing thereof.

When the switch 60 is moved to a closed position, the solenoid 59 is energized to shift the valve 55 to a position communicating the cylinder 44 with the suction pump 33. The piston 45 is then drawn up into the cylinder 44, rotating the sleeve 35 and effecting rotation of the transfer assembly 42. At the time the pick up tube 37 has the nozzle 41 thereof positioned closely adjacent to and in overlying relation to the chain thread, the cam 78 in cooperation with the cam follower 77 closes the switch 68 to energize the thread chain cutter solenoid 70. At this time, the thread chain is cut close to the trailing edge of the previous work and the loose thread chain is drawn up into the horizontal portion 40 of the pick up tube 37 through the nozzle 41.

As has been indicated, the switch 60 is provided with a timer so that it remains closed for only a limited amount of time. This amount of time is, however, sufficient for the transfer assembly 42 to have been rotated to a thread pick up position, the thread chain cutter to be actuated to cut the thread chain, and the loose end of the thread chain picked up into the pick up tube. When the timer 60 automatically opens the circuit to the solenoid 59, the valve 55 returns to its initial position, disconnecting the cylinder 44 from the vacuum pump33. The piston 45 and the piston rod 48 move downwardly, returning the transfer assembly 42 to its initial position.

It is to be noted that when the transfer assembly 42 returns to its initial position, the pick up tube 37 is swung so that the nozzle or opening 41 thereof moves in a vertical plane passing through the needle of the sewing machine and extending along the line of work feed. Thus, the thread chain picked up by the pick up tube 37 is moved back along the line of work feed under the presser foot 84 and in position to be tacked to new work W in the formation of the stitching 83, as is shown in FIG. 10.

It will be readily understood from FIGS. 4 and 9 that the transfer assembly 42 returns to its original retracted position as shown in FIGS. 4 and 9 with the orifice 41 being partially closed by the member 80.

As the new work is passed through the sewing machine, the chain thread 82 will be automatically tacked down by the stitching 83 with the chain thread being progressively drawn out of the nozzle 41. It is to be understood that by properly positioning the chain thread with respect to the new work, the first of the stitches 83 will tack chain thread 82 down with the result that the work will have a pleasing appearance while at the same time the starting end of the stitching will have a reliable closure.

Although only a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the chain thread retrieving and positioning attachment without departing from the spirit and scope of the invention, as defined by the appended claims.

I claim:

1. For use in combination with a sewing machine, apparatus for engaging loose ends of sewing machine stitching and positioning such stitching loose ends in overlying relation to new work for the tacking down of such stitching loose ends automatically during a normal stitching operation on the new work, said apparatus comprising a stitching pick up member, means mounting said member for movement in a plane, and means for mounting said apparatus on a sewing machine with said plane receiving the needle of the sewing machine and said plane extending in the direction of work feed whereby alignment of repositioned stitching loose ends with stitching to be newly formed will be assured and the combined relationship of said two mounting means assuring the movement of said stitching pick up member first to one side of a respective sewing machine needle to pick up a loose thread and then to the opposite side of such needle to position a picked up loose thread in the path of such needle.

2. The apparatus of claim 1 wherein said member is in the form of a suction tube, and said mounting means includes means mounting said suction tube for swinging movement about an axis disposed normal to said plane.

3. The apparatus of claim 2 wherein a vacuum actuated motor is coupled to said suction tube for effecting the swinging thereof.

4. The apparatus of claim 3 wherein said vacuum actuated motor includes an upright cylinder and a piston, said piston having sufficient weight to automatically return said suction tube to a normally retracted position.

5. The apparatus of claim 2 wherein said means for mounting said suction tube for pivotal movement includes a rotary head, and switch means actuatable by said rotary head in response to swinging of said suction tube to a stitch loose end retrieving position.

6. The apparatus of claim 2 wherein said suction tube has a stitch receiving opening and in a normally retracted position of said suction tube closure means engage said suction tube for at least partially closing said opening to increase the suction of said suction tube and the stitch retention characteristics thereof.

7. The apparatus of claim 6 wherein said closure means has resilient engagement with said suction tube and is operable to frictionally resist the withdrawal of a stitch from said suction tube.

8. The apparatus of claim 2 wherein a vacuum actuated motor is coupled to said suction tube for effecting the swinging thereof, a solenoid actuated control valve for controlling the operation of said motor, and a control switch for said control valve actuatable by a sewing machine element.

9. in combination with a sewing machine of the type including a needle, a presser foot and a stitch chain cutter, apparatus for back stitching loose ends of stitching, said apparatus comprising a vacuum source, a suction tube connected to said vacuum source and having a stitch receiving opening, means mounting said suction tube for movement of said suction tube opening in a plane containing said needle and extending in the direction of work feed between a retracted position on one side of said needle and a stitch loose end retrieving position on the opposite side of said needle and return for moving a loose thread into the path of said needle, motor means for effecting movement of said suction first direction, and time delay means for effecting the suction tube reversing movement of said motor means.

11. The combination of claim 9 wherein said motor means includes a vacuum motor, and said control means includes a valve operable to effect movement of said motor in one direction and a timer delay means for rendering said valve inoperable permitting the return movement of said motor.

12. The combination of claim 9 wherein said means mounting said suction tube provides movement of said suction tube opening beneath said presser foot after the lifting thereof.

13. The combination of claim 9 together with control means for said cutter operable in response to swinging movement of said suction tube to a thread retrieving position to actuate said cutter.

14. A method of back tacking a loose end of a sewing machine stitching during a series of sewing operations on separate workpieces comprising the steps of continuing to form stitches after the termination of a sewing operation on a workpiece, cutting the stitch, mechanically engaging the loose end of the stitch by loose stitch retrieving means and while holding the stitch drawing the stitch along a predetermined path reversely of the direction of work feed in a plane passing through the path of needle reciprocation to a location wherein the retrieved stitch extends from the needle in a line directly aligned with and opposite to the direction of ,work feed, and performing a normal sewing operation on a next workpiece with said loose stitching being sewn in place.

15. The method of claim 14 wherein retrieval of the loose stitching and the cutting of the stitching is initiated in response to elevation of a presser foot of the sewing machine.

16. The method of claim 15 wherein the cutting of the stitching is initiated upon the positioning of the loose stitching retrieving means in position to retrieve loose stitching.

17. The method of claim 14 wherein retrieval of of the stitching is initiated upon the positioning of the loose stitching retrieving means in position to retrieve loose stitching.

18. The apparatus of claim 3 wherein said vacuum actuated motor includes an upright cylinder, a piston movable in said cylinder and means for generating a biasing force to automatically return said suction tube to a normally retracted position.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. Dated 17, Q

Inventor(s) WILBUR A. LAUNER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 23, read "26" as 68 Figure 7, there is a thread chain between tube 37 and the looper.

' Signed and Scaled this second Day of September 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (unzmixsinnvr nflalenls and Trudemurkx FORM PC4050 (169) USCOMM-DC 60376-P69 I V u-5 GOVERNMENT PRINTING OFFICE: [959 0-366-334.

Claims

9. In combination with a sewing machine of the type including a needle, a presser foot and a stitch chain cutter, apparatus for back stitching loose ends of stitching, said apparatus comprising a vacuum source, a suction tube connected to said vacuum source and having a stitch receiving opening, means mounting said suction tube for movement of said suction tube opening in a plane containing said needle and extending in the direction of work feed between a retracted position on one side of said needle and a stitch loose end retrieving position on the opposite side of said needle and return for moving a loose thread into the path of said needle, motor means for effecting movement of said suction tube, and control means for said motor means operable in response to lifting of said presser foot to effect the swinging of said suction tube to engage and retract a stitch loose end.

10. The combination of claim 9 wherein said control means includes means to actuate said motor means in a first direction, and time delay means for effecting the suction tube reversing Movement of said motor means.

14. A method of back tacking a loose end of a sewing machine stitching during a series of sewing operations on separate workpieces comprising the steps of continuing to form stitches after the termination of a sewing operation on a workpiece, cutting the stitch, mechanically engaging the loose end of the stitch by loose stitch retrieving means and while holding the stitch drawing the stitch along a predetermined path reversely of the direction of work feed in a plane passing through the path of needle reciprocation to a location wherein the retrieved stitch extends from the needle in a line directly aligned with and opposite to the direction of work feed, and performing a normal sewing operation on a next workpiece with said loose stitching being sewn in place.