US2379882A - Thread case retaining device for sewing machines - Google Patents

Description

July 10, 1945. A. sfcLARK THREAD CASE RETAINING DEVICE FOR SEWING MACHINES Filed April 11, 1944 Patented July 10, 1945 it anananossanammmenavioc FOR SEWIN e memes;

' Alfred s. Clark, Bealy; Mass, mam us United I Shoe Machinery Corporation, Flemington, N. 1., acorporation of. New Jersey v j 5 Application April 11, 1944, serial No. 530,497

Maclai s. (cilia-196 The present invention relates to bobbin or locking thread ease retainingsdevices for lockstitch sewing machihesof the type in which the thread case is mounted foreasy removal from within a rotary loop taker or shuttle tor-carrying loops of needle thread abontthej-thread case. l r

r "In this type of sewing machine,'the threadcase is removed fromthe machine for replenishment of the supply of lockingthread and replaced after a newsupply has been inserted. To 'holdjthe thread case in position and to prevent it from I'D-1 engaging means i is provided in the dorm of l a swinging .meteiiner pivotally supported on the frame of the machine 'for movement, toward and from the thread case; In the machine disclosed in United States Letters Patent No; 473,870,

'talting with the loop taker, suitable thread case granted April 26,..1892, :upon an applicationfiled in the names ofzaehary T. French and William C. Meyer, the parts are 'so arranged that it ispossibie to hold the thread tease manually in position while swinging theretainer toward and from thethread case. When the retainer forms-apart or a cover or door fora protecting case such as is disclosedin United statesvllettersPatent No. 1,302,597,:grahted May :6, 1919;111:011 anapplicationof Thomas H. Seely; it is-impossible to hold the thread casein position manually while swingmg the cover toward and from the thread case. Machines of this type are intendedto he operated with waxed thread the wax from the thread frequently causing the thread case to adhere to the retainer sothat, when the retainer is swung open, the thread case comes withit, falling to the floor and becoming inconvenience.

damaged or resulting in In United States Letters Patent No. 1,471,930,

granted October 23, 1923, upon an application filed in the name of William G. Trohon, a length of resilient wire is bent with a number of coils and a curved substantially horizontal arm of the wire extends across the front of the thread case between the thread case and the retainer. With such a resilient arm, the thread case is held in place when the retainer is swung open and at the same time the thread case may be removed manually merely by flexing the wire to one side. The formation of coils in the wire to provide the necessary amount of yielding movement for easy flexure of the wire while removing the thread case, however, is detrimetal to the strength of the wire and the arm of wire which extends across the front of the thread case is solocated that a loop of thread being carried by the shuttle about the thread case may, under some circummg conditions, frequent replacement may essary.

stances, become impaled on the wire. Asa result,the wire is flexed violently while the impaled loop of thread is being contractedtoward the work. Such flexure may weaken the wire further or change its shape, particularly along those parts Within the coils so that, under ordinaryoperatpeace The objects of the present invention are to avoid the diiiiculties above enumerated and to provide simplified and improved means for preventing 1 displacement of the locking thread in a lockstitch shoe sewing machine of meme referred to even though thethreadcase retainer is swung to openposition er the machine is-op- 'erated through a few sewing cycles without-cu gagement oi the retainer with the thread fease.

The principal features of the invention according'ly reside in a sewing machine or the type a efer-red to provided with a hook needlega look-- ing thread case mounted for easy removal the machine and a loop taker for carrying loops of needle thread about the locking thread case in wlhichthere are provided means for preventmg dis-placement of the thread case comprising a spring arm extending across the exposeds'ideof the'l-oop talcerwith-one end bent across the side of the thread case in the direction of movement of the thread in the needle loop while the loop is being carried by the looptaker about the thread case.-

The loop taker. of the machine in which this feature of the invention is embodied is constructed in aconventional manner with a needle loop entering beak'at the root of which is: formed a throat arranged to carry each loop of needle thread in a circular path about the locking thread case. In the illustrated form of the invention, the horizontal arm of the displacement preventer extends across the loop taker outside the circular path of thethroat so that there is no possibility of a needle loop becoming impaled while being carried about the threadcase.

These and other features of the invention will be clearly understood from the following description; the appended claims, and the accompanying drawing in which Fig. 1 is a view in front elevation of a portion of a shoe sewing machine embodying the invention Fig. 2 is a plan view of the loop taker, thread case and thread case retainer together with means for preventing displacement of the thread case illustrated in Fig. 1; and

Fig. is a detail perspective View of the improved displacement preventer.

The machine illustrated in the drawing except ashereinafter described is the same as that disclosed in the patents above referred to and is provided with a loop taker in the form of a shuttle H) which is rotatably oscillated in a shuttle race l2 at the front bathe machine; "I'hel shuttle r'ace] constitutesa part of a'casing 14 secured by a bolt IE to a lug l8 on the machine frame. The

locking thread is contained in a thread case 20' wire aside or Withdrawing the thread case forwhich is easily removable from-a cylindrical re 'cess in the front of the shuttle, it being retained in the recess and prevented from oscillation with the shuttle by means of asw'ing in'g'; retainer 22,] in the form of a heat retaining case orhoo'd, more fully illustrated and described in the Seely pat ent. I i

The means for preventing displacement locking thread case while swinging the retainer taohment with the machine frame and the ex:

treme end ofthe armfina manner to reduce the strength of the wire or to formirregularities upon Whichthread; or foreignmaterial may become entangled. At the extreme free end'21, the hori zontal armor the displacement preventer is bent throl h a graduallcurvature ofrelatively large radius order toextend downwardly across a side of the thread case in the direction of movement of a loop of eedle'thre ad- .being carried about the, thread case by the looper. A portion of the thread in thelneedle loop is indicated at 28. -It is. evident that, as, the shuttle which is formed with abeakifl picks up each loop of thread, the thread will slide toward a throat 32 i formed' atflthe, root of the beak andv be carried within the throat.aboutqthe thread case through a circul a i a d b he ts a hrl 34;:lTh? hQI'iZ ntaI armifi f the wire is located a substantial distarioeaboveand outside the path 34 taken by the throat of the'shuttle, and the only possible; engagement of the thread in the needle loop with the wire is atits extreme downwardly extending end 21. Since this end i bent in the direction in which the needle loop moves during normal sewing operations, there is no chance for the loop to become impaled on the end of the Wire.

In removing the thread case from the machine, the retainer 22 is opened, and there is suflicieht flexibility in ,tl'ier hdri'zontai ,arm 26 of thdisplaceinent prevehterto enable removal of the thread case either by brushing the preventer wardly until it clears the shuttle and then moving the; thread case laterally. The absence of small radius coil in the preventer not only avoids the'possibility of weakening the wire which, dur- 'fing its m'anufacture'is subject to a high degree of tensile strength and brittleness by drawing,

but. also; eliminates several steps in the manufacture of the preventer. Thus, the expense of manufacture is reduced and a device of greater durability results. 1 a r a J The nature and scope, ofythe invention having beenflindicated and a machine embodying ,the' several features in their preferred form having specifically been describBCL What is claimed is: i 1

1. A- sewing machine having stitch forming devices,lincluding' a locking thread case mounted for easy removal from the, machine, and a loop taker for carrying loops of needle thread about the locking thread case, and: means for prevent-, ing displacement of the thread case comprising a springarm; extending across, the ,loop taker with one ,end bent across, a side ofthe thread case in, the direction of;.,the movement of a loop of, needle thread while being carried by the loop:

taker aboutthe thread case. A v

2.;A sewing machine having stitch forming devices, including a; locking thread case mounted for easy removal from the machine, and. aloop taker, provided witha needle loop entering beak at the root of'whichis formed. a, thread engaging throat, arranged to carr'y, .-each loop of. needle thread in a circularpathabout thelocking thread case, and meansfor preventing displacement of the thread case comprising a spring arm extend-- ing outside the circular path of the loopqtaker throat with its thread case engaging nd inside said circular path bent across a side of the thread casein the, direction-of movement of the thread in the needle :loop,;while-, being carried by the loop taker about the thread. case. i a .i

Ens-CLARK

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