US2773463A - Shirring device - Google Patents

Description

Dec. 11, 1956 J. T. JULLIE 2,773,463

SHIRRING DEVICE Filed MaTCh 1l, 1.954

l L i l Z9 [-D l` I I United States Patent O SHIRRING DEVICE Joseph T. Jullie, Minneapolis, Minn., assignor, by mesne assignments, to The Singer Manufacturing Company, Elizabeth, N. J.

Application March 11, 1954, Serial No. 415,515

1 Claim. (Cl. 112-132) This invention relates to sewing machines which are adapted to stitch and which, under certain conditions such as resetting of cams in the material-feeding mechanism, may be adjusted to shirr material as it is being stitched.

This invention is an improvement on the apparatus and mechanism disclosed in my co-pending application, Serial Number 396,577, entitled Mechanism for Shirring Material at Will While Stitching, now Patent No. 2,711,144, dated June 2l, 1955, and relates particularly to a close cooperative relationship between the improved feed mechanism of my prior application and a cooperating and preferably adjustable novel presser foot of simple and highly advantageous conception.

While my invention is particularly applicable to certain types of sewing machines for trimming and overedge stitching in one operation as manufactured by The Singer Manufacturing Company of Elizabeth, New Jersey, it is also applicable to other sewing machines which utilize, for the feeding of material during stitching, a pair of forward and rearwardly movable or gyratory, generally horizontal feed elements such as feed-dogs for progressively feeding the lmaterial pressed thereagainst during stitching operations. Y

As in my prior, pending application, it is an object to provide highly etlicient mechanism, in sewing machines of the class described, for joining, during the usual stitching operations, the edges of two plies of fabric, at times desired shifting the feed mechanism to shirr the material at will and to the extent desired. My latest invention, however, provides several new and distinct advantages for handling materials varying substantially in texture and thickness and for producing at will resultant shirring upon one of the plies of material without effecting shirring of the other ply.

More specifically, it is an object of the present invention to add, in combinative relationship with the instantly variable feed mechanism of my prior application, a special and novel presser foot which will not only superimpose land guide the edge of the upper ply of fabric for some distance above the foot to render the same ineffective by shirring operation, but which will very precisely guide the edges of the two plies of fabric, one above the other to provide 'the most efficient shirring operation of one of the plies and which will further be adjustable to meet the varying conditions in the textures and thicknesses of various materials upon which the machine is intended to operate.

Another object is the provision, in an instantly controllable feed mechanism for producing shirring at will, of a radically novel and improved presser foot which may be readily attached to the presser bar of conventional sewing machines of the class described and which will accom-v plish the new and valuable results for the shirring of various materials as heretofore set forth.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings ICC wherein like reference characters refer to the same parts throughout the several views and in which:

Figure 1 is a left side elevation of a conventional type of sewing machine adapted for trimming and overedging in one operation and having some portions of the housing and parts broken away to clearly show the relationship of the feed mechanism and my improved presser foot;

Figure 2 is a rear end elevation of the machine on a smaller scale;

Figure 3 is a fragmentary view generally similar to Figure l on an enlarged scale showing the feed-dogs of my mechanism in operation for shirring and showing the cooperating functions of my improved presser foot for producing successful shirring operation upon the lower ply of material;

Figure 4 is a detail plan view of my novel presser foot operatively attached with the presser bar in position for work; and

Figure 5 is a cross section of said presser foot taken on the line 5 5 of Figure 4.

In the embodiment illustrated, my invention is applied to the right and left feed-bar assembly and the conventional presser bar of a standard sewing machine for trimming and overedging in one operation, manufactured by The Singer Manufacturing Company as models #246-3 and #246-5. The conventional mechanism of this machine includes a main frame and housing H, a cloth plate or deck X, a left end pedestal and frame structure L and the usual crank shaft C extending longitudinally across the front portion of the machine for actuating a number of the working mechanisms including the right-hand and left-hand loopers (not shown), the needle-driving shaft assembly (not shown in detail) and the feed mechanism.

The revisions, improvements and alterations of the conventional feed mechanism including its driving connections and quickly shiftable, variable stroke relations of the feedbars and dogs for shirring operation of the instant apparatus are identical with the mechanisms fully disclosed in my said co-pending application, Serial Number 396,577, and will be identified in part by similar numbers, but, being fully disclosed previously, will not be treated in the detail of said prior application.

The conventional left and right-hand gyratory feedbars 7 and 8 respectively are positioned in side-by-side relation at the left end of the machine substantially perpendicular tothe axis of crank shaft C and are eccentrically driven at their forward portions from differential crank portions (not shown) at the left end of crank C. A conventional front feed-bar-slide-block is provided for guiding the front ends of feed-bars 7 and 8 and a rear slide-block 9 (see Fig. l) of conventional structure slidably engages the bifurcated rear ends of feed-bars 7 and 8, said slide-block swinging to permit of gyratory movement of the two bars and to also permit of relative shifting ofthe bars in the working'strokes thereof. The outer or left-hand feed-bar 7 is actuated in conventional manner by a short pitman link 10, the forward, enlarged and semi-circular end of said pitman link being journalled upon a removable cam disc 11 of a predetermined throw, keyed for a predetermined axation to the concentric left-hand extremity of crank shaft C. Camming discs of various pitch or throw are conveniently provided with the particular sewing machine models referred to herein and are numbered in accordance to the throw. As shown and merely as exemplary, a Singer #14 cam (11) is utilized for gyration of pitman 10 while a Singer cam disc #7 is utilized, as shown herein, affixed to the appropriate crank shaft portion inwardly and in juxtaposition to cam 11 (not shown), said second cam actuating -a revised and elongated pitman link 13 disposed inwardly and in side-by-side relation to the short pit- Patented Dec. 1l, 1956 man for effecting the resultant gyration of the inner or right feed-bar 8. The left extremity of crank shaft C is diminished and threaded to receive a heavy retaining nut lflwhich holds the two pitman links 10iand 13 as well as the forward end of the feed-bars in operative position journalled upon the cooperating eccentric portions of the crankshaft C.

The revised and elongated pitrnan linkl 13 of my invention is provided with an elongated, longitudinal slot 13a which is of a Width to accommodate a connector pin 15 having its inner end threaded and atxcd to a tapped socket in the middle of the outer or left-hand feedbar 7. i

The resultant gyrationV and effective stroke of the inner or right-hand feed-bar 8 is produced by a shiftable, stroke-transmitting link indicated as an entirety' by the numeral 16,.having a forward section 16a with a tongue portion pivotally connected by a laterally extendingvconnector bolt 17 with the intermediate and depending portion of the inward or right-hand feed-bar 7, said connector bolt being retained in operative position perpendicularly to tongue section 16a` by a retaining nut 17b threaded upon the outer extremity of pin 17. The connector element 17 is accommodated in the longitudinal slot 13a of the revised and longer pitmanV link 13 and shifts slightiy in said slot in cycles of the gyratory move.- ment of pitman link 13. The rear end of the revised and elongated pitman` link 13 is pivotally connected by a countersunk connector pin `(not shown) with an oscillatory toggle arm (not shown), but having a rear end which is pivoted to the intermediate portion of an upstanding oscillatory mounting bracket 20 provided by` my improved structure and suitably pivoted` at its upper end at the lett side and rear portion of the frame section and pedestal L. As shown, the upper end of mounting bracket 20 is journalled upon the heavy hinge pin 21 upon which the feed-bar-slide-block is also journalled. Mounting bracket 20 is vertically positioned and depends to a point some distance below: the loweredges of pitman links 10 and 13 and is provided with an upwardly extending, slightly rearwardly declined, elongated slot 20a in which shiftable transverse pivot pin 22 for the stroke-transmitting link 16 is accommodated. The relation of the point of connection of the said toggle arm eccentrically of the bracket pivot 21 and the positioning of elongated slot 20a is important in thev proper functioning of my mechanism. To this end, it is desirable that the inward pivot screw 19a (shown in dotted lines in Fig. l) be disposed a short distance downwardly and forwardly of the hinge pin 21 forming the` journal for mounting bracket 20` and that the elongated slot 20a ofthe bracket and the related length of stroke-transmitting link he such that slot 20a approximates an arc or line disposed substantially concentric of the pivotal connection of link 16 at its forward end with right-hand or inner feed-bar 8 through connector pin 17.

My stroke-transmitting link 16, as shown, has a longitudinal rear tapped socket and a rear section 16e of clevis-shape for embracing the sides of mounting bracket` 2t), pivot pin 22 extending through the two sides of said clevis link section and havingv a diminished' threaded extremity which is removably secured in the inner side portion of the clevis. The clevis section 16e of my stroketransmitting link with the pivot 22 is free` to ride or shift A longitudinal shank extension 16e is integrally formedV in the rear end of stroke-transmitting link section 16C for suitable connection with the vertical instantly controllable shift rod' 25 which has its lowerm end bent-out-` wardly (not shown) to provide a connector pin upon which is journalled the horizontal sleeve of a T-shaped connecting element 26 wherein the shank extension 16C is slidably and loosely mounted. The upstanding shift rod 25 has an intermediate head 27a axed thereto which fits with working clearance within a vertical guide tube 27 rigidly secured as by a bracket 23 to the rear of the housing H. A coil spring 29 surrounds the intermediate portion of shift rod 25 within guide tube 27 and is interposed between the head 27a and an abutment block 27e affixed to the lower ,end of tube 27 and axially bored for slidably accommodating shift rod 25. The upper portion of shift rod 25 is externally threaded and projects through a restricted top piece 27b at the upper end of tube 27 and threadedly engages an adjustable stroke-limiting nut 30 above the upper end of said tube.

Suitable means are. provided for instantly pulling shift rod 25. downwardly to its. adjusted length of movement, comprising, as shown, a chain 31.which, at its lower end (not shownlis secured to a suitable, quickly operable treadleV member.

It will be noted that there is no direct pivotal or toggle connection between the elongated or revised pitman link 13 `and its related right-handfeed-bar 8. The toggle arm (not shown) is connected to` eiect the oscillation or reciprocation of the depending mounting bracket 20 which, in turn, communicates to right-hand feed-bar 8 its stroke through the shiftable stroke-transmitting link 16. The longitudinal stroke of right-hand feed-bar, therefore, may be varied, depending upon the shifting of the rear pivot 22. of the transmitting link 16, a long driving stroke beingr imparted, of course, when the transmitting, link pivot is loweredy and consequently, disposed a` greater radi-al distance from the journal 21 of the mounting bracket 20..

Feed-bars 7 and. 8. haveixedly but adjustably attached to the forward and upper, portions thereof, sets of upstanding material-engaging, conventional feed-dogs D-l and D-2, respectively. The front feed-dogs D-1 `are attached to the inner or right feed-bar 8 and the rear feed-dogs D-Zfy are attached in conventional manner to theouter or left feed-bar 7, the operation of said dogs with thestructure described and in conventional machines of the type defined being such that in the cycles of movement,` the two sets of dogs D-l and D2 gyrate together upwardly and longitudinally through equal strokes or distances. Duringv such operation, the cloth is, of course, held. downwardly bya presser foot.

ln Figure l, it will beV noted that shift rod 25 has been depressed to its limit of downward movement to. provide instantaneously for'shirring operation, thereby imparting to the stroke-transmitting.link 16, because of the thenshifted. relation of the pivot pin 22 with the slot of reciprocating mounting bracket 20, a relatively long stroke to the elongated or inner pitman link 13 which controls gyratory and feeding movement of the inner or righthand feed-bar Sand, consequently, the working stroke of the forward feed-dog D-1. In ordinary stitching operation when. shift rod 25 is released, the coil spring 29 retains the rodand consequently the position of thc stroke-transmitting link in its extreme uppermost position relatively to mounting` bracket 20, then transmitting a stroke to my elongated pitman 13 so that the strokes of the two feeding-bars are substantially equal. The forward dog D-l on the inner or'right-hand feed-bar 8 first engages the undersidey of the lowermost ply of fabric.

A conventional, removable throw-plate T is provided in association with clothplate X (see Figure 3) being slotted for accommodatingthe feed-dogs.

In my co-pending application, Serial Number 396,577, I disclosed that it was often desirable in stitching together two pieces of material that only one ply or piece be shirred and, to thisv end, that'the edges of one of the pieces ofi-'material is superimposed overa presser foot and is not affected by shirring operation whereas the underpiece is applied beneath the presser foot and is shirred. I have now discovered that a special and preferably adjustable presser foot for this closely cooperating relationship of feeding, holding and guiding of the plies of fabric to produce shirring will obtain substantially improved and very excellent results, always `giving a true shirring on the under-ply of material without effecting shirring upon the upper ply.

To this end, I provide a novel and improved presser foot, as shown in Figures l, 3, 4 and 5, comprising a main section or body 32 adapted to be rockably secured to the forward end of the conventional pressure bar P.B. in conventional manner andcomprising also a longitudinally adjustable, forward presser section 33 secured forwardly to the body 32 and having its rearward or trailing presser edge 33a disposed in a predetermined spaced relation relative to the forward beveled guiding surface 32a of the first section or body. Said spaced relation provides a transverse fabric-accommodating slot Z, the width of which may be varied precisely for most efficiently accommodating fabric materials varying in nap, texture and thickness. The presser-foot body 32 on its undersurface is shaped like a sled runner for guiding and pressure against the fabric plies U and B affording a smooth, substantially planar surface 321: which extends from the inclined forward portion to the rear extremity of body 32. The forward section 33 of the presser foot includes, as shown, a forwardly inclined, transverse bar 33b having a rearwardly extending, perpendicular attachment arm 33e integrally formed or rigidly attached to the right end thereof. Arm 33e is splined, as shown in Figure 5, to a perpendicular attachment arm 32C integrally formed and extending forwardly at the right side of the forward end of the body or main section 32 of the presser bar. A clamping screw 34 threadedly engages a tapped bore in the supporting arm 32C and works in a short longitudinal slot formed in the arm 33e of the forward presser bar section whereby various longitudinal adjustments within a range in the spaced relations of sections 32 and 33 may be effectively obtained.

The forward section 33, as shown, has a detachable smooth presser plate 35 preferably constructed of steel, secured thereto as by screws 36, the forward portion of said plate lying flush against the underside of section 33 and this plate extending horizontally and rearwardly beneath the lower edge of the transverse portion of section 33 and then rearwardly to deline a predetermined spaced relation between its trailing edge 33a and the most adjacent surface of the nose or forward portion of the first section or body 32.

As clearly shown in Figure 3, the upper ply U of the material overlies and is guided by the upper edge of section 33, and thereafter extends downwardly and rearwardly beneath the main presser section 32. The bottom ply B of material to be stitched to the upper ply U extends in the usual fashion below presser plate 35 and after stitching is commenced, also extends below the presser surface 32b. With the fabric edges so positioned and guided and related to the feed-dogs of the machine, and with the stroke-transmitting link 16 disposed in normal uppermost position, usual overedge stitching is produced as the machine is run.

Operation The operation, in general, of the overall sewing machine illustrated in the drawings in conventional, including the guiding of the several threads employed in stitching operations, the operation of the left and right loopers (not shown), the needle and the trimming operation.

Assuming that two edges of cloth are to be stitched together by overedge stitching and that, in conformance with the desired pattern or lay-out, shirring of the bottom ply B of the material is desired through said certain lengths of the edge, the operati-on with the two plies of fabric properly positioned with edges in alignment disposes the edge of the upper p': y U over the forward presser section, smoothly guided over the round upperedge of the inclined bar 33b thereof and then feeding through slot Z to the presser surfacey 32b of the main section. The bottom ply of material B is positioned at the start below the forward presser `plate 35. At the right side of presser section 32,y the conventional recess 32d is provided for accommodating the needle and the right looper and the side is also contoured for receiving the trimming knife.

When the lay-out or pattern calls for shirring of the material, the operator instantly depresses shift rod 25 (preferably through treadle action) to its limited downward movement, thereby shifting the connector link 16 to the position shown in full lines in Figure 1. In this connection, it should be noted that the downward stroke of shift rod 25 may be adjusted through the setting of the stroke-transmitting nut 30 at the upper end of rod 25.

As previously stated, when the stroke-transmitting link 16 is positioned in the intermediate or lower portion of the bracket slot 20a, a relatively long stroke is imparted through link 16 and connector bolt 17 to the inner or right-hand gyratory feed-bar 8, thus causing the forward feed-dog D-lto engage the bottom ply of fabric B and progress at a slightly greater distance on each operation than progression of the joined and lapped plies U and B above the rear feed-dog D-2. 'Ille differential stroke, in its effect upon the bottom ply, produces shirring in the under ply as long as shift rod 25 is depressed to position the stroke-transmitting link 16, as shown in Figure 1. Immediately upon release of the shift rod, the spring 29 returns the rod and with it the transmitting link 16 to normal positioning where the strokes of the gyratory feed-bars 7 and 8 are equalized.

Extensive experimentation with various types of presser feet and relations of a forwardly disposed presser section for guiding the upper ply of fabric have proven that an accurate and predetermined relationship between the guiding of the upper fabric U with the subsequent lapping of upper and bottom plies U and B must be maintained. The width of the slot Z defined between the trailing edge 33a of the forward presser plate and the opposing rolled surface of the runner-like under surface of body 32 of the presser foot is critical for the particular fabric or fabrics utilized. Thus, with slippery fabrics such as tricot, the width of slot Z must be narrowed to approximately only IAO of an inch. With other fabrics such as brushed rayon, plisse or crepe materials, a relatively larger opening slot must be provided approximating 1/s of an inch. With cotton and heavier woven materials, different and greater adjustments must be made in the width of the slot Z.

With my closely cooperating and improved presser foot, it will be obvious that by loosening the clamping screw 34 and sliding the attachment arm 33e of the forward presser section upon the attachment arm 32e of the body and thereafter tightening said clamping screw, an accurate adjustment may be made for any of the materials within a given range.

To insure eficient stitching of the machine and substantially perfect shirring at the points desired, it is highly important that the edges of the two plies of fabric be precisely positioned and guided by the presser foot and pressure applied during the progressive feeding stroke of dogs D-1 and D-Z at precise areas. The guiding of the upper plate U through a slot must be accurate and my discovery has shown that the slot must confine the various materials utilized closely, but, nevertheless, afford no restriction to passage of the edge of the upper ply. With my improved struoture and the cooperation of the variable feeding mechanism with my novel presser foot, optimum results are produced.

It will, of course, be understood that various changes 7 may be made in the form, details, arrangement and proportions of the parts without departing from the scope of myl invention. i

What I claim is:

A sewingmachine presser-foot comprising an elongated rear section having a substantially at under surface,` a forwardly and upwardly inclined toe portion, and a laterally offset attachment arm at one side thereof; a forward presser and guiding section spaced forwardly of said rear section and including an attachment arm; said two at tachment arms being splined together whereby the said forward section may be slidingly shifted lengthwise of said rear section', said forward section having an inclined plate extending laterally from the forward attachment arm to be disposed in parallelism with and forwardly of the toe portion of said rear section; a thin L-shaped plate having' one limb thereof secured at against the forward inclined face of said plate with the other limb thereof extendingY beneath said plateand terminating in a` transverse edge spaced a shont distance forwardly of the toe portionY of said rear section to provide a transverse slot; and a screw releasably locking said two attachment arms together in` various selected positions of relative adjusti ment Ithereby to vary the width of said slot.

References Cited in the file of this patent UNITED STATES PATENTS

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