US2298770A - Presser foot for sewing machines - Google Patents

Description

y 0d. 13,v 1942. F. A. KUCERA 2,298,770

PRESSER FOOT FORSEWING MACHINES Frank :fucra 7 i ATTORNEYS.

Oct. 13, 1942.

` F. A. KUCERA PREssER FoQT FOR SEWING MACHINES Filed June 27, 1940 2 Sheets-Sheet 2 WITNESs/i F 7gg/rml ran` acera, .y /z/ ,BY 1 v A l l ATTORNEYS.

cated by the angled arrows II-II in Fig. 1.

Patented oct. 13, 1942 PRESSER FOOT FOR SEWING MACHINES Frank A. Kucera, Chicago, Ill., assigner to Union Special Machine Com n poration of Illinois pany, Chicago, Ill., a cor- Application June 27, 1940', Serial No. 342,653

13 claims. l, ,(01. 11e-23,5) y This invention relates to presser feet for chain I stitch sewing machines, and ,has reference more `particularly to chaining-off felling presser feet of lthe general type, Afeatured in U. S. Patent No,

1,718,889 granted to Joseph'Berger on June 25,-:

1929, having independently movable fingers which coact with the feed dogs of the machines in advancing stitch chains connecting successive articles passed through the machine.

Thechief aim of theA present invention is to C make it possible for a presser foot of the above type, to adapt itself more readily to thickness variations in the articles being seamed, thereby to Vease movement of fabric beneath it incident to feeding, without impairment, however, in their efliciency as hold down means, nor interferingv with the actionof the chaining finger or fingers (as the casemaybe) in theabsence of fabric in the sewing machine. 'I'his objective `I attain in practice as hereinafter more fullydisclosed, by constructngthepresser foot with ytwo separate sections or componentsa toe component and a `heel component-which kare pivoted for independent movement to opposite ends of a hori- Vzontal rocker whichis in turnV pivoted at a point intermediate its vends to the lower end of the presser bar; yand' by mounting the chaining 1ingers for pivotal movement about the fulcrum axis of the heel component with their free ends movable up and down through a longitudinal fell guiding slot inthe -toe component of the foot against the resistance of light spring pressure as compared to that which influences the foot proper.

Another object of my invention is to provide `for easement ofthe pressure of the footupon the Ystitch chain during chaining, so that very ne,

aswell as cheaper grades of sewing'threads, may be used without danger of their being cut by the teeth of the feed dog. Such easement I secure in practice, as also more fully set forth later herein, by providing the heel component in its bottom face with a relatively shallowlongitudinal groove for each stitch chain which groove is aligned with the corresponding needle in the direction of feeding.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings wherein Fig, 1 is a view in side elevation `of a felling presser foot con-` veniently embodying my invention, with the contiguous parts of the sewing machine shown in i section.

Fig. 2 is a horizontal section taken as indilscale andshowing the action of the Fig 3 is a view .generally like Fig. 1 but the presser foot in longitudinal section.

Fig.l 4 is .a horizontal' section takenv as indicated by the angled `arrows IV-IV in Fig. 3.

Fig. `5` shows the bottom plan View of the with presser foot.

lFigs.` 6, 7 and V8 areperspective views respectively of the toe and heel sections or components and the chaining iingersof the presser foot.

Fig. 9 is a view like Fig. 3 drawn to a larger presser foot incident to chaining o.

Fig. 10 is a View in elevation toward the left 'hand `end of Fig, 9.

Fig. 211 is a view like Fig. 9 showing the action of the presser foot incident to chain feeding,

Fig. 12 is a view corresponding to Fig. 9 showing the action of the presser footin overriding a cross seam; and

:Fig 13 .is Va `view looking toward the right hand `end of Fig. 12.

As herein illustrated, my improved presser foot oomprises'a shank member I5 with a split collar ISwhi'ch is clamped lto the bottom end of the presser bar Il of the sewing machine by a screw I8. `Extending downwardly atan inclination from ythe collar I6 of the shank member l5 is a clevised' arm I9; and pivoted intermediate its ends bymeans of a screw pin 29 which passes 'through the `opposite sides of said arm I9, is a horizontal rocker 2l in the form of a yoke with forwardlyreaching side portions 22 and a cross- Vwisefconnecting portion or bar 23 at its rear end. `A torsion spring 24, secured by a screw 25 t'o one sidefof the shank .member I5, has its free end fbearing downwardly Aupon the cross bar 23 of the yoked -rocker 2|.

The presser foot Yfurther includes independent toe and heel sections or components 26 and 2l which are separately illustrated in Figs. 6 and 7,

Mthe former being provided with apertured up- `standing ears 23 which are pivotally connected to the forward ends of the side arms 22` of the 'yoked rocker 2| iby screws 29. The front end of the toe component 25 is turned upwardly at an i angle as at 39 to facilitate entry beneath it of the material M of the article which is being seamed ...in the machine, the upturned forepart 30 being `provided with an upright flange 39a which assists in guiding the fellF of the seam. The present presser foot is intendedto be used ordinarily sin association with a folder of the type shown in "U. S. PatentNo. 1,926,950 granted to applicant -vonfSepternber 12, `1933, which is so positioned :that `itsfrontal portion provides a fell guiding wall opposite the flange 36a on the component 26.

The heel component 21 is similarly formed with pierced upstanding ears 3| for pivotal connection, by means of a transverse screw pin 32 to the rear end of the rocker 2|, and, as shown, has its front end bent upwardly as at 33, likewise to facilitate entry of the material M beneath it. The heel component 21 is moreover provided in its bottom face with two narrow relatively shallow longitudinal grooves 34, see Figs. and 10 for a purpose presently sei-l forth.

Fulcrumed for independent movement on the screw pin 32 in the interval between the ears 3| of the heel component 21 are two chaining fingers 35 and 36 whereof the free front or stitch chainengaging ends 35a, 36a extend into a central fell guiding slot 31 in the toe component 26, while the shank portions of said fingers pass through l clearance notches 38 in the upturned portion 33 of said heel component. As illustrated, the stitch chain engaging end portions 350., 36a of the fingers 35, 36 are provided with elongate clearance apertures 39, 40 for passage through them respectively of the needles 4| and 42 of the sewing machine, which needles are transversely spaced and offset relative to each other in the direction of feeding. The loopers partly shown at 43 and 44 in Fig. 9 cooperate with the needles 4| and 42 in a well known way in the concurrent formation of two parallel lines of chain stitches longitudinally of the fell F of the seam. The chaining fingers 35, 36 are subject to the downward pressure of torsion springs 45, 46 which are coiled about the fulcrum pin in the interval between the upstanding ears 3| of the heel component 21, see Fig. 2, one end of each such spring engaging an anchorage rod 41 which extends crosswise between the sides 22 of the yoked rocker 2|. spectively bear upon notched lugs 48, 49 which project upwardly from the chaining fingers 35, 36 about midway between their pivots and free ends.

Arranged to coact with the presser foot to feed the material M is a four-motion feed dog whereof the toothed portions 50 and 5|, operate upwardly in slots 52 and 53 in the throat plate 55 of the machine which latter has parallel bars 56 and 51 extending crosswise of said slots.

Figs. 1 and 2 show the presser foot in normal operation with the fell F of the seam passing in the direction indicated by the arrows through the slot 31 in the toe component 26 while the side portions of the latter rest upon the material M at opposite sides of the fell, and with the heel component 21 bearing on the top of the fell with the full pressure of the usual spring (not illustrated) to which the presser bar |1 is subject.

At this time, the chaining fingers 35, 36 alsoy bear on the top of said fell but with the lighter pressure of the springs 45 and 46, and thus cooperate normally to assist in the feeding of the material.

In Figs. 9 and 10, the material M has passedu from beneath the foot with stitch chains C, C't

trailing behind it in the direction of feeding, the needles 4I and 42 being in their lowered position and the sections 50 and 5I of the feed dog retracted from the material M. Under these con-J The other ends of the springs 45, 46 reback down through the needle hole by the descending needles and into the path of the loopers with attendant breakage of the threads, or to preclude proper subsequent formation of needle loops and resultant skipping of stitches.

When the presser foot subsequently rises in readiness to advance the chains C, C' as shown in Fig. 11, said chains are engaged only between the feed dog section 5| and the heel component 21 of the presser foot, the fingers 35 and 36 having been elevated by the section 56 of said feed dog to substantially clear the chains. Accordingly, the advance of the chains, which immediately follows, is accomplished solely by coaction between the comparatively small areas of the feed dog section 5| and the presser foot heel component 21 and without the full pressure of the usual heavy spring which influences the presser bar |1 by reason of the relief afforded by the shallow grooves 34 in the bottom of said heel component. Thus the likelihood of the chains being cut by the teeth of the feed dog is reduced to a minimum, so that very fine as well as inexpensive threads of the poorer qualities can be successively used in the machine.

Fig. 12 shows how the toe component 26 of the presser foot and the chaining fingers 35, 36 swing about their pivots 29, 32 to allow passage beneath them of a cross seam S in the material M while the latter is held down under full pressure by the heel component 21. In this action, the rocker 2| will move upward about the pin 32 as a fulcrum in opposition to the pressure of the main presser bar spring. In a like manner the heel component 21 of the presser foot will subsequently swing independently about the pin 32 in permitting the cross seam S to pass beneath it, incident to which the rocker 2| will pivot on the screws 29 While the material M is effectively held down by the toe component 26.

When the presser foot is lifted clear of the throat plate 55, the downward movement of the chaining fingers 35 and 36 under the iniiuence of the springs 45, 46 will be limited by engagement of their rear ends (which project rearward beyond the fulcrum pin 32), with the cross bar 23 of the yoked rocker 2|, which cross bar thus constitutes a stop. The spring 24 on the other hand will yieldingly limit clockwise movement of the rocker 2| about the fulcrum pin 26 so that the heel component 21 will be caused to engage with the material M before the toe component 26 when the presser foot is lowered.

The presser foot of my invention is, of course, not limited to two chaining fingers since by modifications well within the scope of the appended claims, the number of the fingers may be increased or decreased to correspond with that of the needles of the sewing machines with which it is intended to be used.

Having thus describedmy invention, I claim:

1. A presser foot for sewing machines, comprising a shank member, a horizontal rocker fulcrumed intermediate its ends to said shank member, separate rockable toe and heel fabric engaging components carried respectively by the front and rear ends of said rocker; and a spring pressed chaining finger having one end fulcrumed adjacent the rear end of said rocker and having its other end operating downwardly in the field of operation of said toe component.

2. A presser foot according to claim l wherein stop means is provided to limit the extent of downward movement of the chaining finger.

3. A presser foot for chain stitch sewing machines comprising a supporting member, a horizontal rocker pivoted intermediate its ends to the supporting member, a toe component pivoted to the front end of the rocker, a heel component pivoted to the rear end of the rocker, a chaining finger also pivotally connected to the rear end of the rocker and having a free end portion operating downward in the field of action of the toe component; and yielding pressure means influential upon the chaining finger. f

4. A presser foot according to claim 3, in which the chaining finger is pivoted coaxially with the heel component.

5. A presser foot according to claim 3, in which the rocker is provided with a stop to limit the downward movement of the spring-pressed chaining finger when the presser foot is lifted.

6. A presser foot according to claim 3, in which the chaining nger has a projection rearward of its fulcrum point, and in which the rocker is provided with a stop adapted to cooperate with such rearward projection in limiting the downward movement of the chaining nger.

7. A presser foot for chain stitch sewing machines comprising a supporting member, a horizontal rocker pivoted intermediate its ends to said member, a toe component pivoted to the front end of the rocker, a heel component pivoted to the rear end of the rocker, a chaining finger also fulcrumed at the rear end of the rocker, and having its free end operating downward in the eld of operation of the toe component and a helical torsion spring surrounding the pivotal axis of the rocker and having a free end bearing downwardly upon the chaining finger at a point intermediate the fulcrum of the latter and its forward end.

8. A presser foot according to claim 3, in which the yielding pressure means bears downward upon the chaining finger at a point intermediate the pivot of the latter and its forward end, and wherein another yielding pressure means bears downward on the rear end of the rocker.

9. A presser foot according to claim 3, in which the heel component has a longitudinal groove in its bottom face whereof the depth is such as to partially relieve the stitch chain of the full pressure of the foot during chaining off in the absence of fabric or material in the machine.

10. A presser foot for chain stitch sewing machines comprising a supporting member, a horizontal rocker pivoted intermediate its ends to the supporting member, a toe component pivoted to the front end of the rocker, a heel component pivoted to the rear end of the rocker, a chaining finger also pivotally connected to the rear end of the rocker and having a free end portion operating downward through a longitudinal fell guiding slot in the toe component; and yielding pressure means inuential upon lsaid chaining finger.

11. A presser foot for use with a sewing machine having a plurality of laterally spaced needles which are offset relative to each other with regard to the direction of feeding, a feed dog, and a throat plate with laterally-spaced slots in which front and rear toothed sections of the feed dog operate upwardly and with cross bars extending crosswise of said slots respectively behind the several needles, said presser foot comprising a supporting member, a horizontal rocker pivoted intermediate its ends to the supporting member, a toe component pivoted to the front end of the rocker and adapted to coact with the front section of the feed dog, a heel component pivoted to the rear end of the rocker and adapted to coact with the rear section of the feed dog, a pair of chaining fingers also pivotally connected with capacity for independent movement to the rear end of the rocker and having free end portions operating downward in the field of action of the toe component and respectively above the cross bars of the throat plate, and individually associated yielding pressure means inuential upon said chaining lingers.

12. A presser foot according to claim 11 in which the chaining fingers extend beyond the respective needles and are provided with longitudinally elongate apertures to clear said needles.

13. A presser foot according to claim 11 in which the free ends of the chaining fingers operate in a longitudinal fell guiding slot in the toe component.

FRANK A. KUCERA.

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