US2525088A - Thread controller for sewing machines - Google Patents

Description

Oct. 10, 1950 F. F. ZEIER 2,525,038

THREAD CONTROLLER FOR SEWING MACHINES Filed March 19, 1948 2 Sheets-Sheet 1 Oct. 10, 1950 F. F. ZEIEB 2.52 88 THREAD CONTI KOLLER FOR SEWING MACHINES Filed March 19, 1948 2 Sheets-Sheet 2 1 u" L 52 3/ 35 T- l3 3 46 M 38 45 a? #8 47 mum INVEN TOE EEDEE/CKF ZEIEB v WITNESS B) ATTOEN TY Patented a. 10, 1950 THREAD CONTROLLER FOR SEWING MACHINES Frederick F. 1Zeier, Stratfield, Conm, assignor .to The Singer Manufacturingflompany, Elizabeth, N. 3., a corporation of New Jersey Application March 19, 1948, SerialNo. 15,80'6,

7 Claims. 1

This invention relates to sewing machines and more particularly to a thread-controller adapted for use in a sewing machine of the type disclosed in my copending application Serial No.. 15,805, filed March 19, 1948. T

The invention has for an object to provide a improved thread-controller which is conveniently accessible for threading.

Another object of the invention is to provide a thread-controller particularly adapted for a needle-feed chain-stitch machine in which the amount of looper travel is small compared to the amount of needle travel, the small looper travel making it desirable to have an effi cient and accurate control of the looper-thread in order to insure the proper formation of the usual thread-triangle for entrance by the needle.

The invention also aims to provide a threadcontroller which is adjustable to control its effect on the looper-thread during the critical portions of the stitch-forming cycle, and to control its eifect on pulling off thread from the source of pply.

The foregoing and other objects and advantages of the invention will best be understood from the following description of an illustrative embodiment thereof shown in the accompanying drawings, in which:

Fig. 1 is a leftside elevation, partly broken away; of a substantially complete feed-off-thearm sewing machine embodying the invention.

Fig.2 is a top plan view of a'section ofthe laterally extending arm of the machine-frame with a portion thereof broken away to illustrate theactuating devices for the rock-shaftcarrying the thread-controller.

Fig. 3' is a top plan'view similar 'to'FigsZ, and

"showing the thread-controller at the beginning of its thread take-up stroke. "Fig. i is a top plan view similar to Fig. 3,'but showing the thread-controller at the end of its Ithread take-up stroke, this view also illustrating the usual tension devices through which the thread travels .prior .to entering the thread-con- .troller.

- Figifiis a perspective view with the cover-plate Referring more in detail tojthe -.drawings, the

.improved thread-controller is shown as embodied the looper includes a frame comprising a standard In of a bracket-arm terminating in an overhanging head i l. Preferably integral with the front side of the standard I 8 is the work-arm casting including an upper forwardly projecting arm l2, a laterally extending arm [3, and a vertically depending arm I4 carrying a horizontal work-supporting arm 15 disposed so that its free end underlies the head ll The stitch-forming mechanism of the present machine comprises a thread-carrying needle l6 carried by the lower end of a needle-bar l'l supported in said head H for endwise reciprocatory work-penetrating and sidewise vibratory workfeeding movements. Cooperating with the needle 16 in the formation of two-thread chain-stitches is a thread-carrying looper 18 mounted upon a looper-carrying. bar l9 extending endwise ofsaid work-supporting arm I5. Assisting the needle and looper in stitch-formation is a movable spreader 2!] which is actuated to swing transversely of the path of travel of the looper to engage and distendthe looper-thread to form the usual triangle with the previous'needle-threadloop for entrance by the descending needle. Supplementing the needle H5 in feeding the work endwise of the work-supporting arm I5, is a lower four-motion feed-dog 21 which is apertured in theusual manner to receive and back-up the needle 5 during the work-feeding movement of the needle. Opposed to the feed-dog 2! is the usual presser-foot 22 carried on the lower end of a spring-biased presser-bar 23 endwise slidably journaled in the head II.

As clearly shown and described in my copending application referred to above, the looper l8 derives its endwise loop-seizing and -shedding movements and its sidewise needle-avoiding movements from mechanism disposed within the vertically depending arm 14. This mechanism includes an actuating rock-shaft 24 journaled in bearing bushings 25 and 26 fixed in the top and bottom walls of the arm [4. v The shaft 24 is operlatively connected at its lower end, by suitable means, to the looper-bar l9 and has clamped to it adjacent its .upper end a rock-arm 21 (Fig. 2) which is connected by a short pitman 28 to .a crank 29' formed on a rotary counter-shaft 30 journaled in the laterally extending arm l3. Rotation of the crank 29 will effect an oscillation of .therock-shaft 24, which in turn will impart an endwise movement to the looper-bar l9giving to 18 its loop-seizing and -shedding strokes. g

In chain-stitch sewing machines it is preferable to operate the looper-thread controlling means from the looper-actuating mechanism in order that exact timing between the looper and the thread-controller can be conveniently obtained. To that end, the present thread-controller is adapted to be fastened on the exposed upper end of the looper-actuating rock-shaft 24. Referring to Fig. 1, it will be seen that the means for securing the thread-controller on the rockshaft 24 includes a pair of opposed clamp-jaws in the form of a thrust-washer 3| and a clamp-disk 32. Extending through alined apertures in the clamp-disk 32 and thrust-washer 3| is a clampscrew 33 threaded into the tapped end of the rock-shaft 24. Secured between the clamp-jaws 3| and 32 are a pair of thread-engaging members 34 and 35, each of which is adapted to be endwise adjusted relative to the axis of the rock-shaft 24 by loosening the clamp-screw 33. It will be understood that when the clamp-screw 33 is loose, the clamp-disk 32 also can be angularly or circularly adjusted about the axis'of the shaft 24. The thread-engaging member 34, which is the shorter of the two members, is bent upwardly at its free end to provide a vertically disposed thread-engaging limb 33 adapted to contact the looper-thread T passing between a stationary thread-guide 3? and the upper end of a threadguiding device 38 secured in a channel 39 formed in the outer wall of depending arm Id. The longer thread-engaging member is also bent upwardly at its free end to provide a thread-engaging limb 40 adapted to contact the looperthread T passing between a stationary threadguide 4| and the thread-guide 31, the upper end of the limb 40 terminating in a reve rsely bent tail 42 which overhangs the looper-thread or threads and prevents them from sliding off the upper end of the thread-engaging limb 43' during the operation thereof.

The two stationary thread- guides 31 and 4| are adjustably secured by means of the screws 43 and 44 upon a supporting angle-bracket 45 which is secured to the side wall of the depending arm I3 by the screws 46 threaded into said arm. A suitable swing-up guardor cover-plate 47 is hinged to the angle-bracket 45 and when the cover-plate is in its lowered or closed position, as shown in Fig. l, the cover-plate serves to guard the operator from inadvertently contacting the rapidly moving take-up arms 34 and 35.

Operation.

When the looper thread-controller is at the beginning of its take-up stroke, which position is illustrated in Fig. 3, the looper I8 is advancing in its loop-seizing stroke endwise of the worksupporting arm I5 in a direction toward the depending arm l l. During this stroke of the looper, slack looper-thread is produced adjacent the looper, and to absorb this slack thread and maintain an accurate control on the looper-thread, the thread-engaging member 34 is caused to swing from the position shown in Fig. 3 to that shown in Fig. 4. In moving to the position shown in Fig. 4, a bight is formed in the looper-thread T between the thread-guide 3'! and the upper end of the thread-guiding device 38, the thread forming the bight being drawn back from that portion of the thread leading to' the looper. By effecting the proper relative adjustment between the thread-engaging member 34 and the threadguide 31, the looper-thread is so controlled that during the entire loop-seizing stroke of the looper I8 and while it is dwelling at the end of its loopseizing stroke, the looper-thread is held sufficiently taut that it is maintained in position to be unerringly seized by the spreader 20 as the latter moves transversely of the looper to spread the thread-triangle for entrance by the descending needle.

In chain-stitch machines it is customary to provide means for drawing thread from the supply during each stitch-forming cycle, which thread is to be used in the subsequent stitchforming cycle. The thread-engaging member 35 of the present device is provided for that purpose. In operation, the thread-engaging arm 35 swings between the two stationary thread-guides 7 and 4 I, forming a bight in the thread as shown in Fig. 4. The thread forming the bight is pulled from the supply through the usual tension device 43 which i used to properly tension the thread in its passage to the looper. It will be observed in Fig. 3 that the vertical limb 40 of the member 35 is spaced from the looper-thread T This is purposely done so that the thread pull-oil action will occur only during the latter part of the active stroke of the thread-engaging arm 35.

From the foregoing, it will be understood that during the initial portion of the active stroke of the thread-controller, only one of the thread-engaging members, namely, member 34, contacts the looper-thread T and not until all the lost motion between the thread-engaging member 35 and the looper-thread is taken up, do both of the thread-engaging members 34 and 35 operate on the looper-thread simultaneously. As shown in Fig. 4, at the end of the active stroke of the two thread-engaging members 34 and 35, member 34 cooperating with the fixed thread-guide 3'! forces the looper-thread to undergo a sharp bend about the thread-guide 31 which results in a snubbing action on the looper-thread and prevents any accidental movement of the thread toward the looper. When the snubbing action on the thread occur it is at a critical time in the stitch-forming cycle when the spreader is operating to distend the looper-thread limb of the thread-triangle. The snubbing action on the thread at this time is desirable because the looper-thread is thereby accurately controlled and maintained elevated within the range of action of the spreader device.

Having thus set forth the nature of the invention, what I claim herein is:

1. In combination with a threaded reciprocatory needle and a complemental thread-carrying looper, looper-operating mechanism including an actuating rock-shaft, of a thread-controlling mechanism including spaced thread guides through which the looper-thread passes, and movable thread-engaging members connected directly to said actuating shaft and disposed so that one of said thread-engaging members operates between the spaced thread-guides and the other operates outside the field between said thread-guides.

2. A sewing machine having, a frame including an overhanging head, a work-supporting arm, and a depending arm carrying said work-supporting arm, an endwise reciprocatory needle carried by said head, a thread-carrying looper supported by said work-supporting arm, mechanism for operating said looper including an actuating shaft journaled in said depending arm and having one of its end-portions exposed, spaced thread-guides mounted on said depending arm, and a'thread-engaging'device mounted on the exposed end-portion of said actuating shaft and ing shaft journaled in said frame, and a threadcontrolling mechanism including spaced threadguides, a pair of movable thread-engaging members disposed to contact the looper-thread adjacent said thread-guides, andaclamp device for securing said thread-engaging members to said actuating shaft, said clamp device providing for adjustment .of said members endwise of themselves and circularly about the longitudinal axis of the actuating shaft.

4. In combination with stitch-forming devices including a threaded reciprocatory needle and a complemental thread-carrying looper, operating means for one of said stitch-forming devices ineluding an actuating rock-shaft, of a threadcontrolling mechanism including spaced threadguides, and a pair of oscillatory thread-engaging members connected directly to said actuating shaft and disposed to operate upon the thread adjacent said thread-guides, said thread-engaging members being relatively arranged so that one is acting on the thread during a greater portion of its oscillation than is the other threadengaging member.

5. A sewing machine having, a frame including an overhanging head and a Work-arm portion including a laterally extending arm, a depending arm carried by said laterally extending arm, and a work-supporting arm carried by said depending arm, an endwise reciprocatory needle carried by said head, a thread-carrying looper supported by said Work-supporting arm, mechanism for actuating said looper including an actuating shaft journaled in said depending arm lengthwise thereof and having its upper end-portion exposed at the top of the laterally extending arm, spaced Number thread-guides, anda thread-engaging device mounted on the exposed end-portion of said actuating shaft and arranged to contact the thread adjacent said thread-guides.

6. Thread-controlling mechanism for sewing machines, comprising, a thread-tension device, spaced thread-guides disposed to successively direct a thread leading from said tension-device, a

thread pull-off member having its I effective thread-engaging path of movement between said thread-guides, a thread take-up member having its effective thread-engaging path of movement at the side of said thread-guides remote from said tension-device, means for vibrating said pull-off and take-up members about a common axis, and means providing for relative adjustment of-said members radially of said axis.

7. In combination with stitch-forming devices including a threaded reciprocatory needle and a complemental thread-carrying looper, operating means for one of said stitch-forming devices including an actuating rock-shaft, of a threadcontrolling mechanism including spaced threadguides, and a pair of movable thread-engaging members connected directly to said actuating shaft and disposed to operate upon the thread adjacent said thread-guides, one of said threadguides and one of said thread-engaging members being relatively arranged so that in one extreme position of movement of said thread-engaging member the thread is snubbed between said member and said thread-guide and thereby effectively locked against accidental movement.

, FREDERICK F. ZEIER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 2,332,932 Riviere Oct. 26, 1943

Images