US2450043A - Sewing machine - Google Patents

Description

Sept. 28, 1948. o. R. HAAs 2,450,043

SEWING MACHINE.

Filed Nov. 1, 1945 5 sheets-sheet 1 n S3 aR//Ms 75462 M252@ r Sept. 28, 1948. o. R. HAAs 2,450,043

SEWING MACHINE Filed N'Qv. 1, 1945 5 Sheets-Sheet 2 Sept. 28, 194s. o. R. HMS 2,450,043

SEWING MACHINE Filed Nov. l. 1945 5 Sheets-Sheet 3 Sp, 23, 1948. Q, R, HAAS .2,450,043

.SEWINGMACHINE Filed Nov. l, 1 945 Y 5 Sheets-Sheet 4 o. R. -HAAs SEWING MACHINE Sept. 28, 1948.

lFiled Nov. l, 1945 5 'Sheets-Sheet 5 Eve/afan 0770 Mus Patented Sept. 28, 1948 p SEWING MACHINE- Otto R. Haas, Beverly, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application November 1, 1945, Serial No. 626,043

19 Claims.

The present invention relates primarily to improvements inhook needle sewing machines more particularly of the lockstitch type ordinarily employed for connecting the outsole with the Welt of a Goodyear Welt shoe, although in its broader aspects the invention is applicable to any type of sewing machine. An example of a machine to whichthe features of the present invention are applicable is disclosed in United States Letters Patent No. 2,056,670, granted October 6, 1936, upon an application of Joseph Gouldbourn et a1.

In order to enable the work to be removed readily, machines of the type referred to above frequently are provided with power actuated cutters for severing the thread at the end of a seam. After severing the thread, the ends remaining in the machine may becomedisplaced from proper position so that in starting a new seam effective sewing operations will not be performed. To avoid this result, it is customary t-o hold the ends of thread manually in their proper respective positionsuntil the first few stitches of a new seam are completed. To insure proper insertion of the initial stitch in a new seam in certain machines employing a thread cutter, mechanical thread holders have been utilized to secure the thread ends in proper sewing position. In the use of mechanical thread holders to secure the thread ends, it is necessary to bring the thread into contact with the holders, usually before severing the thread, and, unless this is done, proper positioning of the thread ends will not be obtained.

One object of the present invention is to provide a sewing Vmachine with means for securing the thread in the machine at a position to insure proper insertion of the initial stitch in a new seam when sewing operations are started, in such a way that no particular attention on the part of thema-chine operator will be required in applying the thread to the securing means, with the result that the entire operation of the machine will be simplified and rendered more effective. Other objects of the invention are t-o improve generally the construction of a sewing machine, particularly of the lockstitch type, in which a more reliable control than heretofore is obtained in thread manipulation and in uniformity with which stitches are set in the work.

In accordance with these objects, a machine embodying the featuresof the present invention comprises, in addition to the usual stitch forming devices, a thread cutter, a pneumatic thread holder means acting at the end of each seam in proximity to the thread cutter to secure .the

thread remaining in the machine with certainty at a position which will insure proper insertion of the initial stitch of a new seam. This feature of the invention, as herein illustrated, includes the provision of a valve for controlling the thread holder in attracting or releasing the thread at the desired times. The use of a pneumatic thread holder with a control valve is of particular .advantage in a machine equipped with a thread cutter, in which the severed end of the thread remaining in the machine after the thread cutter has operated is attracted to the thread holder automatically by the now of air induced thereby. When the machine is equippedwith Va thread cutter, the thread holder valve of the invention may be operated in suitable sequence with the operation of the thread cutter. In a particularly desirable embodiment of this feature, means are provided for retarding the operation of the control valve so that the thread will be retained during insertion of the first few stitches' of a seam.

In the present embodiment of the invention, the pneumatic thread holder consists of a suction pump or its equivalent connected with an orifice on the presser foot or on the work support of the machine, or b-oth,and the valve for controlling Athe thread holder is so arranged as to disconnect the suction side of the pump from the orifice and at certain times to -connect the orifice with the pressure side of the pump, thereby preventing accumulation of foreign material in the orifice when the holder is outfof operation, as during sewing.

According to another feature of the invention, a frictional tensioning device is arranged to act onthe needle thread between the take-up and the looper to cause tension to beimparted to the thread while each loop is engaged with a loop taker and to be rendered inoperative during the taking-up stroke of' the take-up, thus positively preventing application o-f friction by said device. By so doing, the tension on the thread is increased in such a way as to insure proper formation and setting of each stitch at the under surface of the work at whichv the take-up operates while the loop is being engaged by the loop taker. In a lockstitch sewing machine, such tensioning of the thread is effective in drawing the needle thread tightly against the work during each stitch formation. With the use of the tensioning device embodying this feature of the-invention, preferahly a second tensioning device also is employed to assist the thread hook and looper in laying a loop of threadin the needle hook. When a second tensioning device is employed in the form oi the invention herein described, separate mechanisms are provided for actuating both tensioning devices in the proper timed relationship. As a convenient construction for operating the ten- .sioning devices, connections are made with certain o the mechanisms already existing inthe machine for operating the stitch forming devices and, as illustrated, one of the tensioning devices is connected With the thread hook actuating.

' looking from the right-hand side of the machine,

illustrating certain of the stitch forming devices in the machine, including the thread hook, thread measuring pull-oli", and other devices;

Fig. 3 is a detail sectional side view on a further enlarged scale, illustrating mechanism for operating a frictional thread tensioning device for tightening the needle thread against the work;

Fig. 4 is a detail View of the same mechanism in front elevation;

Fig. 5 is a sectional view of a valve for controlling the pneumatic thread holder shown in a position for causing the thread to be secured;

Fig. 6 is a View of the same valve shown in a position to cause the thread to be released;

Fig. 7 is a detail view of the work support in the machine, illustrating a pneumatic thread holding orifice and conduit connected thereto;

Fig. 8 is a detail View partially in section of the work support and presser foot, illustrating the manner in which the thread ends are Secured in position;

Fig. 9 is a perspective view of the presser foot with its thread securing orifice and suction conduits;

Fig. 10 is a detail view of certain of the stitch forming devices in the machine, illustrating their positions during the time at which thread is being given up to the loop taker; and

Fig. 11 is a similar view of the same parts taken during needle looping operations.

The illustrated machine is an outsole shoe sewing machine similar in construction, arrangement, and mode of operation to that of the patent to Gouldbourn et al., above identied, except as hereinafter described. The machine has a supporting column I2 at the upper end of which is a sewing head including stitchforming devices and a driving and stopping mechanism actuated by a foot treadle (not shown) connected to a control rod iii vat the left side of the head as indicated in Fig. 1 of the drawings. When the control rod is rais-ed, the machine is started and, when depressed by releasing the treadle, the machine is brought to rest in a manner more fully disclosed in the prior patent, Also the machine is equipped with a thread cutter similar to that disclosed in United States Letters Patent to Joseph Gouldbourn No. 1,985,605, granted December 25, 1934, except that in the machine of that patent mechanical means is employed to hold the ends of thread remaining in the machine after the threads are severed.

The stitch-forming devices of the machine include a curved hook needle I5, a curved awl i3 (see Fig. l0), a needle looper 2li, a thread hook or nger 22, a loop spreader 24, a loop taker or shuttle v26, a locking thread supply case 2%, a rotary take-up 3U and a needle thread measuring pull-off 32 operating between a pair of thread locks 34 and 36 against which each stitch is set by the take-up. The work is clamped and fed in the'illustrated machine by the action oi a workv support 38 and a presser foot fil), for a more completezexplanation of the operation or which lreference may be had to the Gouldbourn et al.

patent.

In themachine of the present invention, the ends of thread remaining in the machine after being severed by the thread cutter are secured in place by a pneumatic-thread holder, thus eliminating the use of mechanical thread holding parts with their actuating mechanisms within or surrounding the'restricted spaces available about the'sewing point. For securing the thread pneumatically, .a pair of orifices 42, 11:4 (see Figs.

7, 81 and 9) are. provided, one 0n the work engaging surface of the work support and the other on the presser foot, the orices serving to terminate tubular conduits 4S, t8 and 5i! (best shown in Fig. 1 of the drawings), the conduits d5 and d'serving as branches of the main conduit 50. The conduits extend between the orifices and a two-way valve 52 vfor controlling the ow of air in the orifices, and the valve 52 is connected to thesuctionv side of an air pump Sil mounted at the underside of a frame 55 which supports the sewing head oi the machine.

At the end of each sewing operation, the ends of both threads remaining in the machine are attracted by air ilowing through the orices and are secured separately in proper position to start a new seam against surfaces of the work support and 'presser foot through which the orifices open. The threads are readily attracted from the position in which they are severed to the mouths of the orifices by the air currents induced so that there is no necessity for presenting the threads accurately to the orifices by special manual movements of the work or threads in removing the work'from the machine. For this purpose, the orices of the thread holder are located in close proximity to the point of operation of the thread cutter.

The thread cutter comprises a single cutting blade (Fig. l) 58 movably mounted on the machine for severing both threads above and against the surface of the work engaged by the presser foot. To permit both threads to be cut readily after the machine is brought to rest, the machine islbrought to a stopping position with the needle loop of the final stitch pulled but part way downA toward the work'at the side of the presser foot so that a portion of the needle thread surrounding the shuttle thread extends above the work surface. Before severing the threads, suiiicient lengths are withdrawn from the needle supply and locking thread case by pull-oir devices similar to those described in the patent to Gouldbourn so that in forming the i'lrst stitch or a new seam there will be no danger of losing control or the severed ends remaining in the machine.

The means for operating the thread cutter consists of'a rod @il pivotally connected at its upper end to actuating mechanism for the thread cutter and at its lower end to a second foot treadle (also not shown) separate from the treadle for controlling the driving and stopping mechanism in the machine. When the rod 60 is drawn downwardly, the cutter blade is actuated downwardly and inwardly of the machine against the upper surface of the work, which with the illustrated machine ordinarily comprises the projecting marginal portions of the welt and outsole of a shoe. In order for the thread cutter to act effectively, the machine is brought to rest at the end of a seam and the presser foot is lifted by the drivingr and stopping mechanism automatically from engagement with the work. As soon as the presser foot is lifted from the work, the thread cutter operating treadle may be depressed, causing the cutter knife to be projected against the threads and the threads to be severed in the manner previously indicated. After the thread cutter has been operated, the thread cutter treadle is released and the rod rises under the influence of a compression spring 62 coiled about the rod and arranged to act against an upper surface of the sewing head frame 56 and a collar 64 secured to therod. Rising movement of the rod withdraws the thread cutter blade from engagement with the work, thus permitting the work to be withdrawn from the machine with the threads severed in close proximity to the work.

In operating the thread cutter in this way, mechanical connections between the thread cutter operating rod and the air controlled valve 52 cause the suction side of the pump 54 to be connected through the conduit to the orices 42 and 44. The connections between the operating rod 60 and the valve include a pin 66 extending from f the rod 65, a slotted arm of a bell crank lever 68 into the slot of which the pin 66 projects, a link 10 pivotally connected to the other arm of the bell crank lever 68 and terminating `in a slotted end surrounding a pin 'I2 secured in a downwardly extending arm 'I4 fixed to a shaft forming a part of a movable cylindrical valve body 16, best shown in Figs. and 6, the bell crank 68 being fulcrumed on a support 'I5 carried by the frame of the pump 54. The connections thus described are arranged to open the valve for connecting the conduit 5|) to a suction pipe 'I8 extending from the pump 54 with the result that a flow of air is induced to flow into theorices 42 and 44. Suction continues in the orifices so long as the machine remains at rest, the thread cutter operating rod connections being arranged to retain the valve in the position of Fig. 5 with the suction side of the pump connected to the conduit 5|] for this purpose.

To retain the valve body 16 in thread securing position of Fig. 5 after being operated by the thread cutter rod 60 the lower end of the arm 14 xed to the valve forms a detent for engagement with a latch arm on a lever 82. The lever 82 is mounted to turn on a stud 84 projecting from the supporting column I2 and is actuated yieldingly to swing its latch arm against the detent of the arm '|4 by a tension spring 86 stretched between a pin on the lever and an eye screw 88 secured to the column I2. The extreme left end of the lever 82 is forked to receive a roll 9G so disposed as to be engaged by a finger projecting from a collar 92 clamped to the control rod I4 of the driving and stopping mechanism. When the control rod I4 is raised to start the machine in operation at the beginning of a seam, the finger on the collar 92 raises the roll 95 and swings the latch arm of thelever 82 away from the valveV arm 14. As soon as this occurs, the valve body is turned from the position of Fig. 5 to the posi- 6 tion of Figj by contraction of a spring 94 connected at one end to a pin on the valve arm and at the other end to a second pin on the pump frame. During this movement, the pin 12 moves idly along the slot in the link 10.

In moving the valve body 16 to the position of Fig. 6, the suction pipe 'I8 is disconnected from the conduit 59 and connected to an inlet port 9B in the outside housing for the valve. The conduit 50 simultaneously is connected with a pressure tube 98 inserted in the exhaust side of the pump 54, the arrangement being such that, instead of inducing suction, a 'blast of compressed air is `forced through the conduit and the orifices 42 and 44 to eject the threads and to eject any particle of leather or other foreign matter previously lodged therein from the-orifices. In this way, the orifices vare kept clear to insure free movement of air during the suction period. The blast of air through the orifices continues throughout sewing operations and after the machine is brought to rest until the thread cutter is operated as just described.

In order to insure that in starting a new seam the thread ends will be retained briey in their respective positions in contact with the work support and presser foot so that the rst few stitches will be inserted properly, the movement of the valve body from suction position of Fig. 5 to compression position of Fig. 6 is delayed until after the machine starts. For this purpose, the valve arm 'I4 is pivotally connected at |00 with a piston rod |02, the piston of which operates within an air cylinder |94 pivoted at one end thereof to the supporting column I2. The air cylinder |04 is provided with an adjustable bleeder valve |09 and a vent |08 to enable the time of movement of the valve to be regulated and to permit the Valve to be rotated quickly after the desired period of delay is completed. As soon as the piston of the rod |92 passes the vent |08, the valve is quickly shifted from the position of Fig. 5to that of Fig. 6 by the spring 94. In the position of Fig. 5 in which the suction pipe 18 is connectedy to the conduit 59 and the orices in the work support and presser foot, the pressure tube 98 from the pump is vented to the open air through the valve and an outlet port IIS in the housing valve (see Figs. 5 and 6).

Besides ejecting foreign matter from-the orifices, the force of the compressed air therethrough aids in keeping the work and the machine clear of such matter and definitely assists in improving the operation of the machine. Furthermore, the orii'ice 44 in the presser foot is directed across the path of the needle so that it tends to keep the needle loop free from small particles of leather or lint and assists in maintaining a reliable control of the loop under varying operational conditions,y particularly While each needle loop is being disengaged from the loop taker and drawn toward the work.

To enable the Work support an d presser foot to move freely while clamping and releasing the work and while feeding the work, the branch conduits 46..and 48 comprise flexible tubes between the work support and presser foot and the main conduit 50 which is of rigid construction. For connecting the Ibranch tubes with their respective orices 42 and 44 on the work support and presser foot, the work support and presser 'foot are -drilled at ||2 and provided with nipples H3 (see Figs.' '7 and 9) between the ydrillingsr and the're- `7 the continuously rotating type which acts while each loop of thread drawn through the work by the needle is being carried about the loop taker Yto provid-e slack in the thread by giving up Ymore thread than is required for the operation. The

mechanism for actuating the take-up is contained partly within a hollow arm ,I I4 of a gear casing, one member of which is connected to a Sleeve |-|5 for rotating the take-up.

To insure that the thread between the needle looper and the work will have moderate tension applied Ythereto while the needle is being looped in each sewing cycle in spite of the slack pro.-

vided, so that improper looping operations will not occur, rthe machine of the saidGouldbourn et al. patent has an auxiliary thread tensioning device comprising a downwardly extending leaf spring |56, asshown in Fig. 2. The leaf spring H3 is secured to an arm ||8 on the upper end of which the thread nger 22 is formed. As the arm |13 moves rearwardly to assist in laying the thread Vin the barb of the needle, the leaf spring acts yiel-dingly against the thread which passes over a hub of an arm 32! supporting Vthe thread lock 35. This occurs while the thread nger and the looper are acting to lay the thread in the needle barb and continues until the needle looping operation is completed. After the looping operation -is completed, the arm I |3 is moved forwardly and the leaf spring disengages the thread, as indicated in Fig. l2. During continued movenient of the take-up, the thread becomes slack, particularly while each needle loop is -being carriedover the loop taker.

In order to tighten with a reliable tension the thread extending along the surface of the Work engaged by the work support between the stitch being formed and the previously formed stitch, according to a further feature of the present invention, a second needle thread tensioning device is provided acting on the thread between the vtake-up and the loOper during the time in which each individual loop passes over the top of the shuttle at a position of its greatest extension.

In order to reduce the ,strain on the thread thereafter to a minimum during the take-up stroke of lthe take-up, the said second thread tensioning device dsengages the thread and is rendered inoperative directly after the needle loop is released from the shuttle.

The` second needle thread tensioning device embodying this feature of the invention is illustrated in Figs. 2, 3 and 4 and comprises a fixed wear `pla-te |20 having side ilanges between which the needle thread passes, mounted on a bracket |22 secured to the machine frame. Cooperating with the wear plate |20 and acting between its side flanges is a frictioning member |24 in the form of a rearwardly curving and laterally offset arm rotatably mounted on a bushing |26 surrounding` a screw |28. The screw |28 passes loosely through a mounting plate |30 adjustably clamped to a portion of the machine frame and is threaded int an upstanding plate-like portion |32 of the frame, the sleeve and screw providing a rotatable mounting for both the arm H8 of the thread linger as well as for the arm of the tensioning member |24. The arm of the tensioning member |24 is Vformed with an offset to cause it to extend across in front of the thread finger arm -I 8 as-illustrated in Fig.4.

The mechanism for actuating the thread tensoning arm |24 includes a spherically headed bolt |34 clamped in an opening in the arm, a spring link vItthaving at itsuppr end a socket toreceive r8 the spherical head of the bolt |34 and at its lower end a similar socket t receive the spherical head of the bolt |38, secured within a threaded opening in the arm of a right angle lever |40. The lever |40 rotates on an inclined stud screw 42 threaded into -a bracket |44 carried by the machine vframe and, between forked porticns of a downwardly extending arm of .the lever |40, there projects a pin |45 forming a pivotal connection between a link |48 and a plunger |50. The link |48 and plunger |50 include a part of the mechanism for .actuating the thread lock 34 which', as in the vmachine of the said Gouldbourn et al. patent, Iconsists of a sleeve |52 rotatably mounted in a boss portion of the machine frame with a thread engaging block forming the thread lock 34 located in closely spaced relationship to a similar thread engaging block |54 provided with a round- .ed rib portion fitting within an L-shaped bracket il 56 also secured to the machine frame. The connection between the rod |50 and the sleeve |52 includes a compression spring |53 coiled about a reduced portion of the rod and compressed against shoulders within the sleeve and on the rod, a pin ,|50 passing through the sleeve and a slot in the rod to prevent their separation.

The mechanism for actuating the thread lock 34 isY otherwise the same as inA the Gou'ldbourn 4et al. patent. Pivotally connected to the link |48 is a cam actuated lever |62 fulcrumed at |64 on the machine frame and provided at its lower end with a roll |66 engaging a cam |63 on a sewing shaft |10.

The arrangement is such that, during the operation of the machine, the thread lock `34 moves .toward the block |54 to grip the thread therebetween and thereafter the rod |50 continues its movement to apply a greater pressure through th'e spring |58 in clamping the thread. Depending upon the adjustment of the parts for its timing, a similar action takes place in the connections for actuating the thread tensioning member |24, although the force applied to the spring link |36 is less than that applied through the spring |58 `of the thread lock 34, the spring link causing only a tensioning action on the thread rather than a clamping action to grip the thread against movement as in the thread lock.

By this construction and arrangement, both the thread tensioning devices, including the leaf spring I6 and the tensioning member |24, impart africtional effect on the thread at different times in each sewing cycle. The timing of the tensioning devices can be best understood with reference to Figs. l0 and 11 of the drawings. In Fig. 11, the take-up 30 is shown at the beginning of its ygiving-up stroke, and the thread tensioning spring .H6 is shown acting on the thread to assist the thread finger and looper while laying the thread in the hook of the needle to maintain a constant light uniform tension in the thread. As soon as the looping operation is completed, the needle draws the loop thus formed through the work and the leaf spring H5 disengages the thread as indicated in Fig. 10. As the take-up nears the upper end of its giving-up stroke, illustrated in Fig. 10, the frctioning member |24 engages the thread and presses it against the Wear plate |20 to cause the thread at the under surface of the work engaging the work support to be `tightened snugly against the work while the loop of needle thread is being carried over the top of the shuttle 26. As soon as the shuttle has rotated suihciently to enable the needle loop to be disengaged therefrom, the tensioning member |24 is actuated to disengage the thread and to `relieve entirely the frictional effect. The needle loop is then pulled down against the work together Vwith the 4encircled locking thread to complete the stitch in the usual way, both tensioning devices being inoperative during this part of the take-up stroke.

By arranging the oriiice 42 on the work-engaging surface of the work support, the severed end of the thread is secured against withdrawal by the pressure of the work against it when the work is initially clamped in starting a new seam. Such an arrangement enables the use of a frictional tensioning device acting on the thread between the take-up and the looper to assist the operation of the looper in laying the thread in the hook of the needle during the rst stitch of a new The nature and vscope of the invention having i been indicated and a construction embodying several features of the invention having been specifically described, what is claimed is:

1. A sewing machine having a work support,

and stitch forming -devices including a needle and a thread cutter, in combination with means acting after the cutter has-operated to secureY the severed end of the :thread remaining'in the machine at a position to insure proper insertion of the initial stitch of, a new seam when sewing operations are restarted, comprising a pneumatic 'thread holder located in proximity to the thread cutter to attract the end of thread after being severed. I

2. A sewing machine having a work support, stitch forming devices including a needle, work lclamp-ing means, and -a thread cutter, in combination with means acting after the thread cutter has operated to secure the severed end fof :thread remaining in the machine at a position to insure proper insertion of the initial stitch of a new seam when sewing `operations Iare restarted, comprising a suction pump and a conduit connected with the pump having an orifice 'on the work clamping means..

3. A sewing machine having a work support, stitch -forming devices including .a needle, a

thread cutter, `and .means for operatin'g'ythe thread cutter, in combination withv a pneumatic thread holder for securing the thread inthe machine, aV valve for controlling the thread holder, and connections between the operating means for the thread cutter `and the valve arranged to cause the holder :to secure the severed end of the thread after the thread cutter has operated.

4. A sewing machine having a work support, stitch forming devices including a needle', Aa

-thread cutter and means for operating the thread i cutter, ldrivingand stopping mechanism for causing the stitch forming devices to be actuated, and a rod for controlling the driving and stopping mechanism, in combination with a pneumatic :thread holder for securing the end, remaining in the machine ofthe thread severed by the thread cutter, a valve for controlling the thread holder, and operating connections between the controlling rod and the valve arranged to cause the holder to release the thread when sewing operations are restarted. 5. A sewing machine having a work support, stitch forming devices including a needle,^a thread cutter and means for operating the thread cutter, driving and stopping mechanism for causingithe stitch forming devicesV to be actuatedand a rod for controlling the driving and stopping mechanism, in combination with a pneumatic thread hol-der for securing the end remaining in the machine of the thread severed by the thread cutter, a valve for controlling the thread holder, connections between the thread cutter operating means and the valve arranged to cause the holder to secure the thread when the thread cutter is operated, and other connections between the controlling rod and the Valve arranged to cause the holder to release the thread when the stitch forming devices are started.

6. A sewing machine having a work support, stitch forming devices including a needle, a

Y thread cutter and means for operating the thread cutter, driving and stopping mechanism for causing the stitch forming devices to be actuated, and a rod for controlling the driving and stopping mechanism, in combination with a pneumatic thread holder for securing the end remaining in the machine of the thread severed" .by the thread cutter, a valve for controlling the thread holder, connections between the thread cutter operating means andthe valve arranged to cause the holder to secure the thread when the thread cutter is operated, other connections between the controlling rod and the valve arranged to cause the holder to release .the thread when the stitch forming devices are started, and means for retarding the oper-ation of the valve when the controlling rod connections are moved to cause the Ithread to ce retained by the holder du-ring insertion of the rst few stitches of a new seam.

7. A sewing machine' having a work support, stitch forming devices including a needle, a thread cutter and means for operating the thread cutter, driving and stopping mechanism .for causing the stitch forming devices to be actuated, vand a rod for controlling the driving Vand stopping mechanism, in combination with -a pneumatic thread holder for securing the end remaining in the machine of the thread severed by the thread cutter, a valve for controlling the vthread holder, a latch for retaining the Valve in the position to which it is actu-ated by the thread cutter operating mean-s, yielding means for actuating the valve in a direction to cause the holder to release the thread, and a 'connection between the controlling rod and the latch to release the valve for movement by the yielding means when the stitch forming devices are started.

8. A sewing machine having a work support, sti-tch forming devices including a needle, a thread cutter and means for operating the threadY cutter, driving and stopping mechanism for causing the stitch forming devices to .be actuated, and a rod for controlling the driving and stopping mechanism, in combination with a pneumatic thread holder for securing the endV remaining in the machine of the thread severed by the lthread cutter, a valve for controlling the thread holder, a latch for retaining the valve in the .position to which it is actuated by the thread cutter operating means, yielding meansfor actuating the valve in a direction. to cause the holder to release the thread, a connection between the controlling rod and thel'atch to rele-ase the valve for movement by the yielding. means when the stitch forming -devices are ystarted,an'd a dash pot for retard-ing movement of the valve after being released by the latch to cause the thread to beretained by the holder during insertion of the'rst-iew stitches of a new seam.

`9. A sewing machine having a work support and a presser foot for clamping the work, stitch forming devices includin-g a'rn'eedle Vand aA thread cutter, in combination with means for securing the end remaining in :the machine Iof the thread severed by the thread cutter at a position to insure proper insertion of the initial stitch in `the new sea-m when sewing operations are restarted, comprising suction producing means and a conduit having an orice in the presser foot, a 4portion of which conduit includes a flexible tube to enable movement of the presser foot to clamp and rel-ease the work.

10. A lockstitch sewing machine having a work support and a presser foot for clamping and feeding the work, stitch forming devices Vincluding a needle and a shuttle, and a thread cutter, in combination with means for securing the ends remaining in the machine of the threads severed by the thread cutter at a position to insure proper insertion of the initial stitch in a new seam when sewing operations are restarted, comprising suction producing means and conduits having orices on the presser foot and work support, a portion of each of which conduits includes a flexible tube to'enable free work feeding movement of the work support and presser foot.

1l. A sewing machine having stitch forming devices including a needle and work clamping means, in combination with means for securing the thread remaining in the machine at the end of a seam in a position to insure proper insertion of the initial stitch of a new seam when sewing operations are restarted, comprising an air pump, a conduit connected with the pump having an oriiice in the work clamping means, and a valve in said conduit for producing suction in the ori fice to secure the end of thread after sewing operations are terminated and for producing pressure in said conduit to prevent accumulation of for eign matter in said orifice during sewing opera tions.

12. A sewing machine having stitch forming devices including a needle and work clamping means, in combination with means for securing the thread remaining in the machine at the end of a `seam in a position to insure proper insertion of the initial stitch of a new seam when sewing operations are restarted, comprising an air pump, a conduit connected with lthe-pumphaving an oriiice in the work clampingv means, a valve in said conduit for producing suction inthe orifice to secure the end of thread after sewing operations are terminated and for producing pressure in said conduit to prevent accumulation of foreign mat ter in said orifice during sewingoperations, and means for retarding the movement of the valve when sewing operations are started to cause the thread to be retained by the thread securing means during insertion of the first few stitches.

13. A sewing machine having a workA support and a presser foot for clamping the work and having an orifice, two-thread lockstitch forming devices, and a thread cutter' acting to sever'both threads when the stitch forming devices are brought to rest, in combination with means for securing the ends remaining in the machine'of the threads severed by the threadcutter' at a position to insure proper'insertion ofthe initial stitch of a new seam when sewing operation's'are` restarted, comprising suction'producing means and conduit means having orices in the' work support and presser foot.

14. A sewing machine having a hook'needle; a loop taker, a looper and a thread hookfor laying a loop of thread in the needle hook, a take-up, and mechanism for actuating the take-up to pro# vide slack inthe needle thread duringthe'giving up stroke vof the Atake-up, in'combination' with a' of which applies tension 'while each needle'loop is being engaged by the loop taker to insure proper tightening of the needle thread againstthe work;

15. A sewing machine having a hook needle,a loop taker, a looper and a thready hook forlaying a loop of thread in the needle hook, a take-up; mechanism for actuating the take-upto provide slack in the needle thread during the vgiving-up` stroke of the take-up, in combination with a pair of tensioning devices both of which engage lthe thread between the take-up and the looper and are rendered inoperative during the taking-'up' stroke of the take-up and one of which'applies tension to the'thread whilev each loop ofl thread' is being laid in the needle hook and the other of' which applies tension while each needle :loop is being engaged by the loop taker to insure proper tightening of the needle thread against the work', and separate mechanisms for actuating the tensioning devices at said times during each sewing cycle.

16. A sewing machine having a hook needle, a loop taker, a looper and a thread hook for laying a loop of thread in the'needle hook, a' take-up, mechanism for actuating the take-up to provide slack in the needle thread during the giving-up stroke of the take-up, in combination with a pair of tensioning devices both of which engage the thread between the take-up and the Alooper and are rendered inoperative during the'taking-up stroke of the take-up and one ofwhich applies tension to the thread while each loop of 'thread is being laid in the needle hook and the other 'of which applies tension while each needle loop is being engaged by the loop taker to insure proper tightening of the needle thread against the work, and separate mechanisms including a connection withthe thread hook for'actuating the tensioning devices. d

17. A sewing machinehaving a'hook needle', a-looper and a thread'hook for laying'a loopoil thread in the needle hook, a'loop taker, atake-up, mechanism for actuating the take-up to provide slackV in' the needle'thread'as each needleloop is acted Yupon'by the loop taker, thread measuring means 'including a pull-01T and a thread lock, and mechanism for actuating said measuring means, in combination with a pair of thread tensioning devices acting on the thread between the take-up and the looper, and separate mechanisms for Aactuating said tensioning devices during each sewing cycleto relieve'the Vtension on' the thread during' the majorv part of the taking-upl stroke, comprising' a connection with'the thread vrhook and a connection withV themechanism `for 'actua ating the thread lock.

18. A sewing .machine having a hook needle.' a looper, -anda thread hook forlaying aV loop of thread in the needle hook, mechanism foractuating thefthread hook, a loop taker, a take-up, thread measuring means includingla pull-01T and a thread lock, and mechanisms for actuating said measuring means, in combination with a' pairof thread tensioning devicesacting onthezthread between the take-upand the'looper, a connection between' the thread. hook actuating mechanism and one of the tensioning devices for causing said device to apply tension to the thread while each loop of thread is being laid in the needle hook and to relieve the tension at other times, and a connection between the thread lock actuating mechanism and the other tensioning device for causing said tensioning device to apply a tension to the thread while each needle loop is being engaged by the loop taker.

19. A sewing machine having a work support, stitch forming devices including a hook needle, a looper, and a take-up, work clamping means, a frictional tensioning device acting on the thread between the take-up and the looper to assist the operation of the looper in laying the thread in the hook of the needle, and a thread cutter, in combination with means acting after the thread cutter has operated to secure the severed end of thread remaining in the machine at a position on REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,403,518 Molyneux Jan. 17, 1922 1,985,605 Gouldbourn Dec. 25, 1934 2,056,670 Gouldbourn et al. Oct. 6, 1936 2,358,860 Kestell Sept. 26, 1944

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