US1941481A - Single thread sewing machine - Google Patents

Description

Jan. 2, 1934. M, McClANN 1,941,481

SINGLE THREAD SEWING MACHINE Filed July 12, 1929 3 Sheets-Sheet l 1 mum IN V EN TOR. W7 WAC/9,454 M Cfl/v/v 5 ATTORNEY 3 Sheets-Sheet 2 INVENTOR. Ma /6 f! We C/i/v/v ATTORNEYS.

Jan, 2, 1934. M. M CANN SINGLE THREAD SEWING MACHINE Filed July 12 1929 Jan. 2, 1934. M. M CANN SINGLE THREAD SEWING MACHINE Filed July 12, 1929 5 Sheets-Sheet 3 IN V E TOR. Awe/4454 C'fl/v/v BY 5 I l A TTORNEY Patented Jan. 2, 1934 PATENT GFFICE SINGLE THREAD SEWING MACHINE Michael McCann, Glen Morris, N. Y., assignor to Frederick Osann Company, New York, N. Y., a corporation of New York Application July 12, 1929. Serial No. 377,736

Claims.

My present invention relates to chain stitch or single thread sewing machines, and particularly to button sewing machines. The general object is to provide such a machine with improved means 5 for controlling the position of the thread loop engaged by the revolving looper of the sewing machine while the needle is below the work, and particularly while the needle is descending preparatory to the formation of a new loop about which the first mentioned loop will be subsequently cast. More specifically, the object of the invention is to provide a loop deflector or loop positioning arm or finger and operating mechanism for the latter which are characterized by the positive and easy movements of the operating parts, the simplicity and ruggedness of the oper ating mechanism, its reliability in operation, and its capacity for continuous operation at relatively high speeds.

A further object of the invention is to provide a sewing machine of the type mentioned with a simple and effective needle guide operative to return the free end of the needle into proper relation with the loop taking hook when the needle has been deflected away from the hook by the work penetrated. My improved needle guide and improved loop deflector are preferably combined in a single movable part.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described preferred embodiments of my invention.

Of the drawings:-

Fig. l is an elevation with parts broken away and in section of a portion of a button sewing machine;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a sectional elevation of a portion of the machine, the section being taken at right angles to Fig. 1.

Fig. 4 is a partial section on the line 4--4 of Fig. 3;

Fig. 5 is a plan view of the hook;

Fig. 6 is a plan view of a portion of the machine;

Fig. 7 is a sectional elevation showing relative positions of parts including the thread finger when the latter is in the position shown in Fig. 6;

Figs. 8, 9, 10 and 11 are views taken similarly to Fig. 7, showing positions successively occupied by the parts as the button sewing operation proceeds;

Fig. 12 is a view taken similarly to Fig. 6, with 7 the parts shown in the positions occupied by them 6 0 in Fig; 10;

Fig. 13 is an elevation taken similarly to Fig.

1, illustrating a modification of a portion of the apparatus shown in Figs. 1 and 2; and

Fig. 14 is a view taken at right angles to Fig. 13. 0B

In the drawings, A represents the bed of a button sewing machine of well known type comprising a cloth plate portion 13 with an elongated needle opening B for the vertically movable needle C. Above the cloth plate is located a but- 76' ton clamp D, and beneath the cloth plate is located the rotary looper E which may be of the usual type and is carried by a rotating shaft e.

The shaft e is driven through the coupling ea by the driving shaft eb, and it will be understood that the latter is operatively connected in any usual or suitable manner with the means for supporting the needle C and giving the latter its usual movements. The relative movements of the needle and the button necessary for the successive penetration of diiierent holes in the button may be effected by mechanism of any usual or suitable type for the purpose. It is to be noted, however, that the loop deflecting means herein provided are of especial utility in a button sew ing machine in which the needle is caused to successively penetrate difierent thread openings in the button by shifting the needle and not the button holder. It is unnecessary to illustrate and describe mechanism for giving the needle its movements as the details of such mechanism form nopart of the present invention, and mechanisms for the purpose are well known.

In accordance with the present invention the limbs of a previously formed thread loop which is engaged by the looper during the descent of the needle through the work and the cloth plate in the formation of a second loop to be drawn through the first mentioned loop by the looper, are positioned with respect to the path of the descending needle by a loop deflector or thread positioning arm or finger f. The latter is similar in purpose and in the general character of its movements parallel to the plane of looper rotation, to the loop positioning arm or finger of 05 the prior Lyons Patents Nos. 788,213 and 856,645. The loop positioning means disclosed and claimed herein differ from the loop positioning means of said prior patents, however, in various respects contributing to mechanical simplification, case of movement, and the avoidance of lost motion or vibration, these advantages of my improvement being especially important in button sewing machines intended and adapted for operation at high speed.

In accordance with the present invention, the loop positioner or deflector f is carried by an oscillating support, which, in the preferred construction illustrated, comprises a carrier arm F which curves about the looper axis and is rigidly secured to a rock shaft G located beneath and parallel to the shaft e. The shaft G is mounted in bearings A and A carried by the machine bed, and in which the shaft G is oscillated about its own axis to thereby give the loop deflector f its movements as hereinafter described. Advantageously the bearing A comprises an elongated bearing sleeve axially adjustable in an opening in the bed, being normally secured in the desired adjustment by a set screw A The sleeve of bearing A extends between a collar G on the shaft G and the hub of the arm F which may be adjusted in the direction of the length of the shaft G by a corresponding adjustment of said sleeve.

The preferred mechanism shown for giving the shaft G its oscillatory movements in proper timed relations with the movements of the needle and the looper, comprises a cam member H mounted on the hook shaft e and rotating with the latter. The cam H is caused to oscillate the shaft G by its engagement with an arm'G. The latter is adjustably clamped to the shaft G and is held against the periphery of the cam H by a tension spring K shown as connected at one end to the bed of the machine and at the other end to a projection or hook G secured to the arm G. The major portion of the periphery of the cam H is cylindrical and co-axial with the hook shaft e, but a portion H of the cam H is cut away and shaped to give oscillatory movements to the shaft G and thereby to the thread finger F.

For ease and definiteness of description, I shall refer to points or positions at the right hand side of any reference point or part, as seen in Figs. 1, 6 and 12 as at the inner side of said reference point or part, and shall refer to points or positions at the left of a reference point, as at the outer side of the latter. Similarly, a point or position to the right of a reference point as seen in Figs. '7 to 11, inclusive, will be referred to as a rear or rearward point or position, and a point or position to the left of the last mentioned refence point, as seen in said figures, will be referred to as a front or forward point or position, such use of the terms rear, rearward, front and forward, being predicated on the fact, that the beak E of the looper E moves from the right to the left in Figs. 7 to 11 in moving through its loop seizing position.

In the preferred construction illustrated, the thread finger 7 projects outwardly and forwardly from the outer side of the tip F of the carrier arm F. Advantageously, the thread finger f is made separable from the carrier arm F and is detachably secured to the latter. This facilitates replacement and adjustment. As shown, the thread finger f is in the form of a curved barb projecting through an aperture in the tip end F of the arm F, and having a body portion f adjustably clamped against the inner side of the arm F by a clamping screw P.

In Figs. 6 and 7, parts are shown in the position occupied by them as the needle is completing an initial loop forming operation with the thread loop extending through a rear thread hole 2 in a button I which is being attached to fabric J. Figs. 8, 9 and 10 represent successive positions of the parts during the operation of forming a loop extending through a forward thread opening 2" in the button I. As the needle C- begins to descend from the position shown in Figs. 6 and '7, the advancing thread finger engages the limbs of the thread loop then surrounding the looper E as shown in Fig. 8, and moves the thread portions engaged forwardly. Preferably, as shown, the shape of the finger is such that the loop portions engaged are moved inwardly as well as forwardly.

In particular, as the needle passes downward through the work in moving from the position shown in Fig. 8 to that shown in Fig. 9, there is no tendency for the needle to pass to the inward side of either of the loop limb portions t extending between the work and the deflecting finger 1 when the latter is used. The passage of the needle between the upper loop limb portions t which may occasionally occur if no loop defiector or a less efficient loop deflector is employed, ordinarily results in a missed stitch. This is due to the fact that when the needle, after passing between the loop limb portions t passes between the lower portions t and t of the loop limbs as shown in Fig. 9, the needle then really passes out of the loop which is about to be cast off so that when said loop is'subsequently cast off, it does not surround the new loo-p then caught on the looper beak. In addition to this major advantage, the action of the thread finger tends to eliminate occasional thread snarls due to faulty thread tension, or difficulties in the sewing operation such as may be due to irregularities in the fabric, or in the button shape or disposition.

As shown in Fig. 11, the loop deflector f operatively engages and deflects the loop about to be penetrated by the needle, when that loop extends downward from the front thread hole opening 2" in the button I. Those skilled in the art will understand, however, that the practical advantages of the loop deflecting means shown are largely confined to the operations in which the loop engaged by the thread finger extends downward from a rear buttonthread opening 2. This is in large part due to the disposition of the portions of the limb of the loop then between the loop deflecting finger and the work, but is in part due, also to the relative increase in looper speed which occurs in the operation of the standard forms of chain stitch mechanisms having the usual coupling ea between the shafts eh and e, as the looper turns from the position shown in Fig. 9 into the position shown in Fig. 10.

Advantageously, though not necessarily, the front end of the elongated needle opening B in the cioth plate B as shown in Figs. 6 to 12, is laterally enlarged at its inner side. The enlargement B provides a clearance space for the portion of the thread loop between the thread finger f and the work when the thread loop engaged by the finger 1 extends through the front button thread opening 2'.

A characteristic advantage of the loop deflector mechanism disclosed is that the simple outwardly and forwardly extending finger f not only deflects the loop operatively engaged forwardly and 1 1.

inwardly against the back wall of the thread opening when the thread finger moves forwardly from the position shown in Fig. 7 into that shown in Fig. 10, but when, on the return stroke of the thread finger from the position shown in Fig. 10

back to the position shown in Fig. 7', the thread finger f engages the loop then: caught on the looper, the loop so engaged is harmlessly brushed aside.

The present invention is of especial utility, as previously pointed out, in sewing machines like that shown in said Patent No. 788,213, in which the button is held stationary, and the needle is automatically shifted as required for the penetration of the different thread openings in the button. The invention is not without utility, however, in machines like that shown in said Patent No. 856,645 in which the normal needle movement is in a straight line, and in which the button is shifted to present first one and then another thread opening to the needle. While in such case the positions of the needle and the looper are always the same when a loop is taken on the looper beak E, except as the needle may be strained from its normal position by the work, the upper end of the loop engaged by the looper is nevertheless alternately in front, and at the rear of the needle, and when at the rear of the needle there is an objectionable tendency toward an improper penetration of the loop by the needle.

Advantageously and as shown, the thread finger arm F is provided with a branch or tine F having a needle guide surface which extends substantially parallel to the length of the needle slot B and which extends forwardly from the normal needle position when the latter is descending into proximity with the looper. The needle guide surface is beveled off as shown in Fig. 3, and serves to deflect the needle inwardly into proper position relative to the looper E, whenever as may occasionally occur, the needle is deflected by the work forwardly of its normal position. This eliminates or greatly minimizes occasional stitch formation failures otherwise experienced from the failure of the looper hook to pass between the needle and the thread passing to the eye of the needle from the work. With the elongation of the needle guide surface shown, said surface is equally effective whether the needle is passing through the front or rear button thread opening 1', or i, of a machine in which the needle is shifted to penetrate difierent thread openings.

The character of the loop deflecting and loop guiding provisions illustrated and described permits the thread finger and its supporting provisions to be made strong and rigid, and to have easy movements with an avoidance of lost motion, so that little or no difliculty from vibration or lost motion is experienced in operation at high speed. The fact that the shaft G is located below the shaft 6 and hence at a considerable radial distance from the deflecting finger 1, permits the latter to be given operative movement of ample extent by a relatively small angular movement of the shaft G, and said operative movements of the finger f therefore depart but little from the horizontal movements of the loop deflecting finger obtained with the mechanisms of said prior patents. The mechanical simplicity and ruggedness of the construction also contribute to successful high speed operation since there is practically nothing to get out of order or to require especial careful adjustment.

In the modification shown in Figs. 13 and 14, the simple cam H and spring pressed follower G of Figs. 1 and 2, are replaced by a compound cam HA, adjustably secured on the shaft e, as by a set screw H and having two axially displaced cam portions HA and HB. The cam portion HA may be similar in shape to: the cam of the con.- struction first described, and; is engaged: by a lever arm GA adjustably secured. to the rockshaft G. The lever GA and cam part HA give the thread deflector its movements in one, direction. The movements in the return direction imparted to the rock shaft G inthe construction first described by the spring K, are impartedto. the rock shaft in the construction shown in Figs. 1:31 and 14, by a cam follower lever arm GB adjustably secured to the shaft G and engaging the cam part H3. The arrangement shown in: Figs. 13: and 14 is easier to adjust and somewhat more positive in its action than the arrangement shown Figs. 1 and 2.

While in accordance with the prosisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having now described my invention what I claim as new and desire to secure by Letters Paten 1s:

1. In a single thread sewing machine, the combination with a looper and its supporting shaft, of a rock shaft parallel to the looper shaft and at the opposite side of the latter from the work, an arm secured at one end to said rock shaft and provided at its other end with a needle guide surface and with a loop deflecting part, said surface and part being moved between the looper and the work when said rock shaft is oscillated.

2. In a single thread sewing machine, the combination with a reciprocating needle, a looper shaft, a looper carried by said shaft and continuously rotated in the same plane by said shaft to successively seize, expand and cast-off chain stitch needle thread loops, a loop deflecting member restrained against movement transversely of said plane but movable parallel to said plane between the looper and the work to engage the limbs of a needle loop on the looper and move the same out of the path of the needle, and means for operating said member comprising a rock shaft operatively connected to said member and arranged parallel to said looper shaft and at the opposite side of said looper from the work.

3. In a single thread sewing machine, the combination with a reciprocating needle, of a looper shaft, a looper carried by said shaft and. continuously rotated in the same plane by said shaft to successively seize, expand and cast-off chain stitch needle thread loops, a loop deflecting member restrained against movement transversely of said plane but movable parallel to said plane between the looper and the work to engage the limbs of a needle loop on the looper and move the same forwardly out of the path of the needle, and means for operating said member comprising a rock shaft to which said member is secured, said rock shaft being arranged parallel to said looper shaft and at the opposite side of said looper from the work, and a carrier arm secured to said shaft and curving about the looper axis, said member being mounted on the free end of said arm.

4. In a single thread sewing machine, the combination with a reciprocating needle, of a looper shaft, a looper carried by said shaft and continuously rotated in the same plane by said shaft to successively seize, expand and cast-off chain stitch needle thread loops, a loop deflecting member restrained against movement transversely of said plane but movable parallel to said plane above the looper to engage the limbs of a needle loop on the looper and move the same forwardly out of the path of the needle, and means for operating said member comprising an oscillatable rock shaft to which said member is secured, said rock shaft being arranged parallel to said looper shaft and at the opposite side of said looper from the loop engaging portion of said member, a cam carried by said looper shaft at the inner side of said looper, and an arm engaging said cam and secured to said rock shaft.

5. In a single thread sewing machine, the combination with a reciprocating needle, of a looper shaft, a looper carried by said shaft and continuously rotated in the same plane by said shaft to successively seize, expand and cast-off chain stitch needle thread loops, a loop deflecting member restrained against movement transversely of said plane but movable parallel to said plane above the looper to engage the limbs of a needle loop on the looper and shaped to move the same when engaged inwardly and forwardly out of the path of the needle, and means for operating said member comprising an oscillatable rock shaft to which said member is secured, said rock shaft being arranged parallel to said looper shaft and at the opposite side of said looper from the loop engaging portion of said member.

MICHAEL MCCANN.

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