US1983555A - Method of and apparatus for forming group stitches - Google Patents

Description

M. M CANN Dec. 11, 1934.

METHOD OF AND APPARATUS FOR FORMING GROUP STITCHES Filed 001;. 12, 1931 3 Sheets-Sheet l I N V EN TOR. M/c/MEL M Ca n/xv ATTORNEY M. M CANN Dec. 11, 1934.

METHGD OF. AND APPARATUS FOR FORMING GROUP STITCHES Filed Oct. 12, 193-1 5 Sheets-Sheet 2 INVENTOR. M01145; M Cmv/v A TTORNEY Dec. 11, 1934. r M. M CANN AND APPARATUS FOR FORMING GROUP STITCHES METHOD 01? Filed Oct. 12, 1931 3 Sheets-Sheet 5 why RC WW (I N m a m g m ATTORNEY Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE METHOD OF AND APPARATUS FOR FORM- ING GROUP STITCHES Application October 12,

- 10 Claims.

The primary object of the present invention is to provide improved needle thread controlling means and methods for use in conjunction with stitch forming mechanisms of ordinary types and methods, to form the initial needle thread stitch forming loop or loops of a group of successively formed stitches more properly, and, in particular, to draw those loops more tightly, than would be the case if the initial stitch or stitches were formed wholly by such prior mechanisms and without the use of my improved means and methods. The invention was especially devised, and is especially adapted for use in the construction and operation of group stitching sewing machines, such as button sewing machines, comprising provisions normally efiective to form a predetermined number of stitches in each cycle of operation.

In the operation of any ordinary stitch forming mechanism, the initial stitch or stitches formed at the beginning of each sewing operation, are ordinarily formed less perfectly, and, in particular, are less tightly drawn than are the subsequently formed stitches as a result of the fact that the initial end of the needle thread is not sufiiciently restrained by its frictional engagement with the work, to prevent a portion of the thread end being drawn through the work during .the formation of the initial needle .thread stitch forming loop or loops. This isv particularly objectionable in the operation of group stitching machines such as button sewing machines, where it is especially important that every stitch of each group should be properly formed and tightened. In such group stitching machines, it is also desirable to insure that each end of the portion of the needle thread incorporated in a group of stitches should be properly secured to prevent subsequent loosening of the stitches when subjected to conditions, as in the subsequent laundering of the goods, tending to loosen the stitches.

For the general purposes served by the present invention, sewing machines, and in particular group stitch sewing machines such as button sewing machines, heretofore used and proposed for use, have been provided with means for engaging the free end of the needle thread to hold it against undue movement into or through the work as initial stitches are formed. but such prior provisions known to me are unduly complicated in their structure or operation, and/or are more or less unsatisfactory in operation, and usually involve undue needle thread wastage.

In accordance with the present invention, I insure properly formed initial stitchtS Without;

1931, Serial 'No. 568,318

undue thread wastage by the operation of thread engaging and controlling parts, desirably simple and efiective in their construction and operation. In carrying out the present invention, I follow the known practice of the art in employing a thread clamp which grips the free end of the needle thread depending from the work as the needle completes its first upstroke following the initial penetration of the work by the needle in each group stitching operation, but depart from the prior art practices by augmenting the normal take-up action on'the needle thread occurring during said upstroke and before said clamp grips the thread. The additional thread drawn up through the eye of the needle as a result of the augmented take-up action during said first needle upstroke is returned and used during the succeeding upstroke of the needle in the expansion of the first finished needle thread stitch loop by the underbed mechanism cooperating with the needle in the stitch forming operation.

With the described method of operation, the mechanism used to grip the free end of the needle thread may be desirably simple in construction and operation, and in particular, may have the easy movements desirable for use in sewing machines operating at high speed, particularly as the release of said thread end may occur at any convenient stage in the sewing operation following the completion of sufficient stitches to properly secure the portion of the thread passing through the work.

The mechanism provided for engaging the free end of the needle thread at the beginning of the stitch forming operation may be provided with or operate simple and effective thread severing devices for trimming away a waste end portion of the needle thread, and for cutting the needle thread from the work at the conclusion of the group stitching operation. In addition to the general characteristics mentioned above, my present invention comprises various novel features of construction and arrangement.

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, and the advantages possessed by it, reference should be had to the accompanying drawings and descriptive matter, in which I have described a preferred embodiment of the invention. v

oi the drawings:

Fig. 1 is a side elevation of the machine with the side cover plate removed and certain parts shown in dotted lines;

Fig. 2 is a front elevation of the machine frame;

Fig. 2A is a section on the line 2A2A of Fig. 2;

Fig. 3 is a plan view of the machine;

Fig. 4 is an inverted plan of the machine;

FiFig. 5 is a vertical section on the line 5-5 of Fig. 6 is a partial horizontal section on the line 6-6 of Fig. 1;

Fig. 7 is a plan view of the underbed thread clamping and severing means with certain parts in section on the line 7---'? of Fig. 1; and

Fig. 8 is a section taken on the line 88 of Fi 7.

In the accompanying drawings, I have illustrated the use of the present invention in a button sewing machine which in its general organization is of the type illustrated in the patents, to Plumley No. 1,671,124, granted May 29th, 1928, and Lyons No. 1,691,246, granted November 13th, 1928. The sewing machine frame A comprises, bed, standard, arm and head portions. Journalled in the bed portion of the frame is a main driving shaft B, which rotates a looper shaft C through a shaft C which is gear connected at C to the shaft B and is connected to the shaft C by the connection C usually employed in such machines for alternately accelerating and retarding the rotative speed of the looper shaft relative to that of the driving shaft. At its free end the looper shaft C carries a looner CA working under the throat plate a of the machine.

The needle bar D is mounted in upper and lower bearing members DA and DG, respectively. The upper bearing member DA is pivotally connected to the frame A to turn about a horizontal axis intersecting the axis of the needle bar, and the lower bearing member DG is pivotally connected to and supported by a lever G. The lever G is journalled on a vertical pivot G carried by the frame, and is oscillated on said pivot to position the needle to enter differently located button thread holes on successive down strokes of the needle.

The needle bar D is given its up and down needle stroke movements in its bearing members DA and DG, by a crank arm D link connected to the needle bar and carried by an oscillating needle bar shaft D The latter is journalled in the arm portion of the frame A and is oscillated by means of a connecting rod E pivotally connected at its upper end to a crank arm DE secured to the needle bar shaft and having an eccentric strap at its lower end encircling an eccentric disc BE carried by the main shaft-B. The main shaft B is provided with a worm B rotating a gear wheel F secured to a vertical cam shaft F journalled in the frame. At its upper end the cam shaft F carries a cam disc FA. The latter is formed with a closed or continuous cam groove FG in its upper face, which receives a cam stud g carried by the lever G and thereby oscillates the lever G on the pivot G.

In the normal operation of the particular machine shown, the cam shaft F makes one complete rotation during the formation of each group of stitches formed in a single complete sewing operation or cycle of the machine. The cam groove FG is so shaped that during all but a small final portion of each sewing operation, the lever G, and thereby the lower bearing DG for the needle bar, are oscillating back and forth in timed relation with the oscillations of the needle bar shaft, so that the needle d will alternately penetrate button thread holes at opposite sides of the vertical plane including the axis of the bearing member DA. During the final portion of each stitching operation in which the needle makes two or three final downward strokes, the oscillation of the lever G is interrupted owing to the entrance of the stud 9 into a smooth portion FG' of the cam groove FG. In consequence, on said two or three final down strokes of the needle d, the latter will penetrate the same button thread hole and thereby form knotting stitches as distinguished from sewing stitches.

The button operated on is held by a button clamp h. carried by a button clamp support arm H which is pivotally connected to a sliding work support member HA. The latter is mounted in a guideway in the bed portion of the frame, for to and fro movements in a direction parallel to the needle bar shaft, and is given such movements when necessary, as-in sewing on buttons having four thread holes, by means of a vertical crank shaft I journalled in the bed. The shaft I has an upper crank arm I suitably connected to the work holder slide member HA and has a lower crank arm I carrying a cam stud I received in a slot FI formed in the underside of a cam disc FB secured to the lower end of the cam shaft F.

The driving shaft B of the machine is rotated by a driving pulley BJ loosely mounted on the shaft B, but normally coupled to the latter by the engagement of a driving projection BJ' at one side of the pulley with an arm B secured to the shaft B. The driving pulley is moved longitudinally of the shaft B to shift the driving projection BJ into and out of the path of the arm B by a cam J secured to an oscillating stop motion shaft J. The cam J has an operating edge inclined to the plane of the pulley BJ and working in a groove BJ formed in the hub of the pulley and moves the latter' along the shaft B when the shaft J is rotated. During the stitch forming operation the stop motion shaft J is held in the angular position in which the projection BJ and arm B couple the driving pulley to the driving shaft, by a stop latch lever FJ' then engaging a latch part J carried by the shaft J. As each group stitching operation is completed, however, a tripping projection FJ carried by the cam shaft F engages an adjustable plate part FJ of the lever, FJ' and shifts the latter out of the path of the latch part J whereupon a spring J turns the shaft J so that the cam J moves the pulley BJ longitudinally of the shaft B thereby uncoupling the pulley and drive shaft. The plate part FJ is made adjustable in order that the timing of the tripping action may be varied to suit the different speeds at which the machine may be run. The uncoupling movement of the shaft Cir J swings an abutment arm J carried by the latter intothe path of movement of the arm B carried by the driving shaft and thus positively arrests the rotation of the latter. The impact of the arm B against the abutment arm J is cushioned by a cushion spring J carried by the arm J After being thus automatically stopped, the machine may be restarted by manual rotation of the shaft J to re-engage the parts EU and J In practice such rotation of the shaft J may be effected by a treadle lever not shown in the drawings.

Mounted in the arm of the frame A alongside the needle bar is a rock shaft K having arms K and K. The arm K is connected by a chain K to the button clamp arm H and the arm K is provided with a treadle connection K by which' the shaft K may be rotated to lift the button clamp away from the cloth plate for the insertion and removal of the goods to which the buttons are sewed. A spring KA coiled about the shaft K normally holds the latter in' the position in which the button clamp may press the work against the cloth plate. A spring plunger H with its lower end resting on the button clamp arm H normally holds the button clamp against the work and thereby clamps the latter against the cloth plate with the desired pressure.

The feed of the thread from the source of the supply towards the needle is guided and controlled by various stationary guides which need not be described, and by an intermittent thread tension or'clamp L, a steady thread tension M, an intermittent thread clamp N, and other parts hereinafter mentioned. The intermittent thread tension L comprises discs L between which the thread passes and a spring L which tends to press the discs together and thereby clamp the thread between them, during all except a small final portion of each upstroke of the needle bar. During said final upstroke portion and thereafter until the following down'stroke is nearly completed, the upper of the two discs L' is pressed upward by a plunger L so that the thread is then permitted to pass freely through the tension device L. A' spring L tends at all times to depress the plunger L but the latter is periodically raised by a cam LB carried by the main shaft B. The steady tension device M comprises the usual tension discs between which the thread passes, and the usual adjustable tension spring pressing the discs together.

The intermittent thread clamp N comprises a stationary abutment and a plunger N, which, when raised, clamps the thread between its upper end and the under side of the abutment. Normally the plunger N' is depressed, and does not interfere with the feed of the thread, but during the initial and final portions of each group forming operation, the plunger N is raised to clamp the thread. The plunger N is so raised by an actuating lever NF journalled on a pivot pin NS and having a projection NF at its underside. The projection NF extends into the-path of movement of a cam projection NF carried by the cam disc FA. As the latter turns into the position occupied by it just prior to the completion of each group stitching operation, the projection NF engages the projection NF and raises the latter, and thereby the plunger N, with the result that the thread is then positively gripped by the device N.

A thread puller arm 0 is secured to the rock shaft K. Whenthe rock shaft K is oscillated to raise the button clamp after the completion of a group stitching operation, the arm 0 draws thread through the steady tension device M for use in an early portion of a subsequent group stitching operation. At that time the thread is positively gripped by the thread clamp N so that the action of the thread puller 0 does not tend to draw thread back through the eye of the needle. The needle bar carries a take-up thread guide D about which the thread is looped, and to which the thread passes from a stationary thread guide A carried by the head of the sewing machine.

In respect to the features of construction and arrangement hereinbefore specifically described, the button sewing machine disclosed herein comprises nothing now novel with me, but is a typical example of the known sewing machine with which the present invention may be employed with advantage.

The means provided in accordance with the present invention for gripping and severing the thread below the throat plate comprise a reciprocating thread nipping and cutter part P located below the throat plate and given its movements by the cam shaft F. As shown the device P comprises an operative blade portion parallel to and immediately beneath the throat plate A of the machine, and a base portion P connected by screws P to a carrier member PF. The latter is mounted in a guideway in the frame bed for movement in a direction parallel to the driving shaft of the machine, and is given such movement by means of a link connection PF to a lever PF pivoted to the machine frame at PF and carrying a cam stud PF working in a cam groove pf formed in the upper side of a cam disc FC secured to the cam shaft F immediately above the cam disc FB. To insure that the link PF should be adjustable, and such adjustability is secured in the construction illustrated,

by forming the link with two overlapping end portions, which may be rigidly but adjustably secured together by the clamping screw and slot connection shown in Fig. 7. The cam discs F3 and FC might be made integral, but to facilitate cam adjustments and the replacement of one cam disc by another having a differently formed cam groove, the two cam discsFB and FC are preferably made separable and are connected by means permitting angular adjustment of each disc relative to the cam shaft F.

The cam groove pf comprises portions pf, pf M and pf located at varying distances from the axis of the shaft F. At the beginning of each group stitching operation the cam stud PF is within the portion pf of the cam groove pf and the thread engaging edge P of the part P is then at the right hand side of the needle hole A in the throat plate of the machine as the latter is seen in Fig. '7. As the rotation of the cam FC moves the stud PF out of the portion pf and into the portion M of the cam slot pf, the part P is moved across the needle hole A in the throat plate and the depending end of the needle thread is engaged by the edge P and defiected to one side of the needle hole, and as this movement of the part P is completed, the thread is positively clamped between the part P and a cooperating thread clamping surface Q. As the continued rotation of the cam FC moves the'stud PF out of the portion pf and into the portion M of the cam groove, the part P is given a slight further movement to the left so that the portion of the thread end depending below the thread engaging edge P is severed by the coaction of that edge with a stationary cutting edge q. The further rotation of the cam FC moves the stud PF out of the portion pf and into the portion pf of the cam grodve PF, and thereby returns the thread engaging portion of the part P far enough to the severs the limb of the thread loop then running from the looper CA to the work. The parts are so proportioned that the needle thread will thus be cut from the work at a suitable distance from the latter.

Advantageously and as shown the clamping surface Q is formed by the underside of a thin plate Q which is permanently connected .by a pivot pin Q to the thickened body portion of the member q the latter comprising a thin plate portion which is spaced away from the part Q sufiiciently to permit the entrance into the space between them of the part P. The sharpened cutting edge q is formed on the member q. The unit comprising the parts Q and q and the connecting pivot Q are detachably connected to the underside of the throat plate by clamping screws Q and Q The clamping screw Q forms a means for springing the thin plate portion of the part q toward the part P as required to insure efiective shearing action of the edges P and q. By removing the screws Q and Q the said unit may be detached from the machine, and the part q may then be turned at right angles to the part Q to facilitate the resharpening of the cutter surface q. As shown the member P is formed with tapered projections P at each end of the thread engaging edge 19 extending to the left of the latter as seen in Fig. Tl. Projections 1P cooperate with oppositely extending proj ctions of the part q located at the opposite ends of the cutting edge (1 to insure the proper entrance of the part P into the space between the parts Q and q when the part P thereby avoids all tendency of the parts to jam and break as a result of wear and lost motion which may develop in the use of the apparatus. Advanta- 'geously the projections P and q are beveled or tapered as shown.

In addition to the normal take up action on the needle thread produced at each reciprocation of the needle bar by the consequent relative 'movements of the thread guides D and A, the

needle thread is subjected to an additional take up action at the beginning of each group stitching operation by an auxiliary take up S. The auxiliary take up S comprises stationary aper- .'tured thread guide parts S extending upward from the top of the frame arm and a vertically 'movable plunger S located between the parts S. The plunger S is formed with a thread aperture at its upper end and is normally held in a lower position, shown in Fig. l, by a spring S The lower end of the plunger S is pivotally connected to a lever SF pivotally mounted on the pivot pin NS and is provided at its underside with a cam projection SF in the path of movement of a cam stud SE carried on the upper side of the cam disc FA. Once in each rotation of the cam shaft F, the projection SF engages the projection SF and thereby elevates the lever SF.

When the. further rotation of the cam shaft F carries the cam projection SF beyond the projection SF, the plunger S and lever SF drop back into their original positions. The auxiliary take up S acts on a portion of the needle thread extending from the intermittent thread clamp N to the main take up and thence to the needle.

! During and for some time after the stage of operation in which the plunger S is being elevated means creases the amount of thread then drawn back out of the work.

A stationary spring thread tension device It is advantageously arranged to act on the portion of the needle thread passing to the needle from the main take up thread guide D As shown the tension device R is in the form of a piece of resilient metal secured to the head of the machine frame and having an end portion bent back alongside its body portion. The thread passes between and is frictionally gripped by said end and body portions of the tension device R. The latter exerts only a moderate resistance to the movement of the thread through it, but its action is sumcient to prevent the thread from moving with the needle at times when it would otherwise do so simply as the result of the frictional engagement of the thread with the needle eye. The tension device R thus tends to hold taut the por= tion of the thread passing from the tension R to This results in a more even lay of the thread passing from the one hole in the button to the other, and also avoids slack thread around the point of the needle during its descent and the resultant liability to thread puncture by the needle.

A thread deflector arm T carried by the rock shaft K has its lower thread engaging portion T moved from its normal position shown in full lines in Fig. 2, into its dotted line position shown in Fig. 2, and thence back into its full line position, by the oscillation of the shaft K required to raise and lower the button clamp. The lower end T of the arm T extends transversely to the general direction of the arm and moves across the line of action of the needle, which is then in its elevated position, as the arm T is moved between its full and dotted line positions. As the arm T moves from its full line position into its dotted line position the needle thread, then passing from the eye of the needle down into the work, enters a thread receiving slot T formed in the arm portion T. In the subsequent portion of its movement into its dotted line position the arm T draws the needle thread out of the work, the thread having been cut away from the work by the action of the cutting edge P In the dotted line position of the arm T the end of the thread depending from the slot T is held at one side of the button clamp as the latter and the work are adjusted for a subsequent button sewing operation. The inclined slot T has an enlarged inner end forming a pocket T so shaped that on the return of the arm T into its full line .position the thread will be retained in the pocket T and the depending end of the thread will thereby be held out of position in which it might accidently be engaged and held by the button clamp as the latter is lowered or be punctured by the needle on the initial subsequent descent of the latter. On such descent of the needle the latter pulls the free end of the needle thread up out of the pocket T of the arm T.

Little or no additional explanation seems necessary to a full understanding of the operation of the machine. As the needle starts to make its initial upstroke in the formation of a group of stitches, the looper CA engages the needle thread and starts to expand a thread loop in the usual manner. This'does not result in the and take-up provisions of the machine, the free end of the needle thread is pulled through the work and depends from the latter. As the upstroke of the needle is being completed, the part P is moved across the needle hole opening A in the throat'plate of the machine, and the depending end of the needle thread is first defiected to one side of said opening by the edge P of, the part P and is then clamped between the part P and the clamping surface Q. This thread clamping action occurs at about the end of the first upstroke of the needle.

The amount of thread depending below the edge P when the thread is thus clamped is desirably short as a result of the fact that the auxiliary take-up plunger S is elevated during the initial upstroke of the needle, its take-up action being completed at or about the time at which the thread is clamped between the part P and surface Q. At this time, as has been previously explained, the intermittent thread clamp N prevehts movement of the thread through that clamp.

On the second upstroke of the needle, a stitch forming loop is expanded by the looper CA, while the end of the needle .thread is still being held by the clamping action of the part P and surface Q. The supply of thread required for the expansion of the loop on the second upstroke of the needle is furnished in part by the action of the auxiliary take-up 5, since the plunger S is permitted to descend at or about the time at which the needle begins its second upstroke. In other words, during the second upstroke of the needle, the auxiliary take-up 8' gives back the thread drawn from the work by that plunger during the first upstroke of the needle. Additional thread required for the expansion of the loop reflected during-the second upstroke of the needle is drawn through the intermittent thread clamp N. The latter releases the needle thread at about the beginning of the second upstroke of the needle, thereby making available the thread previously pulled through the tensions M and L by the pull-oif O.

After the completion of the second upstroke of the needle, the sewing operation is carried out as it would be if the machine did not include the auxiliary take-up S and intermittent thread clamp N until just prior to the end of the group stitching operation, at which time the intermittent thread clamp is again caused to clamp the thread by the engagement of the studs NF and NF. At approximately the same time at which said engagement occurs, the stud PF enters the portion pf of the cam groove in the cam disc FC and shifts the part P into the position in which its edge P severs the needle thread from the work. Almost immediately thereafter, the stop motion tripping projection FJ engages the latch lever EU and thereby effects the stoppage of the machine.

The machine may be arranged so that the waste end portion of the thread depending below the edges P and q is sheared off by those edges at any convenient time after the thread is clamped between the part P and surface Q and before the part P is'moved to cause its edge P to cut the needle thread from the work. As shown, the cam slot portions pf, pf and pf are so relatively disposed that the severing of the waste end portion of the needle thread occurs shortly before the edge P cuts the needle thread away from the work. The studs NF and NF are so relatively arranged that the thread is gripped by the intermittent thread clamp N, from a time just prior .to the stoppage of the machine at the end of one group stitching operation until about the beginning of the second upstroke of the needle occurring in'the following group stitching operation.

While in accordance with the provisions 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 casescertain 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 Patent, is:

1. In forming a group of stitches, the method which consists in first passing the end of a thread and thereafter passing adjacent loop portions of said thread successively through the work from one side, expanding each such loop at the other side of the work and interlocking it with the following loop passed through the work, holding the thread at a point on the first mentioned side of the work against movement toward the work during the passage of the thread end through the I work and thereafter until the initial loop subsequently passed through the work has been expanded, subjecting the portion of the thread between said point and the work to a take up action following each passage of the thread through the work whereby in expanding each loop subsequent to said initial loop thread is drawn into the expanded loop from the previously formed loop and the latter is tightened, subjecting the said thread portion to a supplemental take up action increasing the. amount of thread drawn back through during the first two down strokes and first up stroke of the needle at the beginning of a group stitching operation, and a take up acting on the needle thread between the said clamp and the work on each up stroke of the needle, and in combination therewith, a supplemental take up acting on the thread between said thread clamp and work during the first up stroke of the needle, and means for gripping the free end of the needle thread depending from the needle as the latter completes said first up stroke.

3. A group stitching sewing machine having a reciprocating needle, cooperating underbed stitch forming mechanism, a thread clamp holding the needle thread against feeding movement toward the work during the first two down strokes and first up stroke of the needle at the beginning of a group stitching operation, a take up acting on the needle thread between said clamp and the work on each up stroke of the needle, and means acting on the needle thread at the thread supply side of said take up preventing feeding movement of the needle thread toward the work during each up stroke of the needle, and in combination therewith a supplemental take up acting on the thread between said thread clamp and work during the first up stroke of the needle, and means for gripping the free end of the thread depending from the needle as the latter completes said first up stroke.

4. A group stitch sewing machine having a jogging work support, a reciprocating needle, cooperating stitch forming means beneath said work support, a thread clamp holding the needle thread against feeding movement toward the work during the first two down strokes and first up stroke of the needle at the beginning of each group stitching operation and during the final portion of each such operation, a take up acting on the needle thread between said clamp and the work on each up stroke of the needle, a second thread clamp engaging the needle thread on the thread supply side of the first clamp to prevent feeding movement of the needle thread toward the work during each up stroke of the needle, means for raising the work support to facilitate the insertion and removal of the work at the end of each group stitching operation, and a thread puller acting on the thread between the two clamps and actuated by the last mentioned means to draw thread past said second clamp when said support is raised, and in combination therewith, a supplemental take up acting onthe thread between the first mentioned thread clamp and work during said first up stroke of the needle, and means for gripping the free end of the thread depending from the needle as the latter completes said first up stroke.

5. A group stitch sewing machine having a work support, a reciprocating needle normally above the work support, cooperating stitch forming means beneath the work support, and means for raising the work support to facilitate the insertion and removal of the work, and in combination therewith, a thread deflecting device actuated by the last mentioned means to move across the path of the needle between the latter and the worksupport when the latter is raised from a normal position at one side of said path and to return to said normal position when the work support is lowered, said device having a thread engaging pocket shaped to receive the thread portion extending between the needle and the work support on its movement awayirom said normal position, and to loosely retain said thread portion when returned to said normal position. i

6. A group stitch sewing machine having a reciprocating needle, cooperating underbed loop forming mechanism, a thread clamp clamping the needle thread at the end of each group stitching operation and holding it against movement toward the work during the first two down strokes and first up stroke of the needle at the beginning of the following group stitching operation, and a take-up acting on the needle thread between the said clamp and the work on each upstroke of the needle, and in combination therewith, a supplemental take-up acting on the thread between said thread clamp and work during the first up stroke of the needle, and means comprising an underbed thread gripping and severing member moving in timed relation with the group stitching operation, to grip the free end of the needle thread depending from the needle as the latter completes said first up stroke, and to sever the waste end of the needle thread while the latter is so gripped, and to sever the needle thread from the work as the group stitching operation is being completed.

7. A group stitch sewing machine having a reciprocating needle, cooperating underbed loop forming mechanism, a thread clamp clamping the needle thread at the end of each group stitching operation and to hold the thread so clamped against movement toward the work during the first two down strokes and first up stroke or the needle at the beginning of the following group stitching operatiomeand a take-up acting on the needle thread between the said clamp and the work on each up stroke of the needle, and in combination therewith, a supplemental take-up acting on the thread between said thread clamp and work during the first up stroke of the needle, and means comprising an underbed thread grip= ping and severing part member, and means for giving said member forward and return movements in timed relation with the group stitching operation to cause said member to grip the free end of the needle thread depending from the needle as the latter completes said first upstroke on an initial forward movement of said member and a further forwardmovement to sever the waste end of the needle thread while the latter is so gripped, and on a return movement of said member to cause the latter to sever the needle thread from the work as the group stitching operation is being completed.

8. A group stitch sewing machine comprising a reciprocating needle and cooperatinglunderbed loop forming mechanism, and in combination therewith an underbed thread gripping and severing mechanism comprising stationary upper and lower blades and a movable member, and means moving'said member in timed relation with the group stitching operation across the path of needle movement and into shearing relation with the said upper blade to thereby clamp the depending end of the needle thread during an initial forward movement occurring during the first up stroke of the needle in each group stitching operation, and during a subsequent further forward movement into shearing relation with the lower blade to thereby sever the waste end of the needle thread, and back across the needle path and into the position in which the rear edge of the member engages the thread portion extending from the work to the first mentioned mechanism as the group stitching op eration isbeing completed, said rear edge being sharpened and severing said portion on such engagement.

9. A group stitch sewing machine having a bed, a reciprocating needle and cooperating un-g derbed loop forming mechanism, and in combination therewith, an underbed thread gripping and severing mechanism comprising a stationary device and a movable member, said stationary device being detachably secured to said bed and comprising an upper blade with which said member cooperates to grip the depending end of the needle thread and having a lower blade with which said member cooperates to sever the waste portion of said needle thread end, and a pivotal connection between said blades permitting a relative adjustment of said blades when disconnected- 10. A group stitch sewing machine having a reciprocating needle and cooperating underbed loop forming mechanism, and in combination therewith, an underbed thread gripping and severing mechanism comprising a stationary device having upper and lower blades each of which has 'a thread engaging portion and a movable member having a thread engaging portion cooperating with said upper blade to grip the de-Y pending end of the needle thread and cooperating with said lower blade to sever the waste portion of said needle thread, and said blades and member having cooperating portions at the sides of their thread engaging portions for guiding the movements of said member as the latter moves into and out of thread engaging cooperation with said blades. 7

MICHAEL McCANN.

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