Overcasting sewing machine



OVERCAS'TING SEWING MACHINE Filed Oct. 2, 1943 5 Sheets-Sheet 3 ANTHONY SARDU INVENTOR ATTORNEY 0a. 15, 1946. A, SARDU 2,409,592 OVERCASTING SEWING MACHINE Filed Oct. 2; 194a 5 Shets-Sheet 4 ANTHONY SAR DU INVENTOR ATTORNEY bct.1 5',1946. v A.'SARDU' OVERCASTING SEWING MACHINE! FiledOt. 2, 1945 L 5 Sheets-Sheet s ANTHONY sARou NVENTOR ATTQRNEY Patented Oct. 15, 1946 UNITED STATES PATENT OFFICE OVERCASTING SEWING MACHINE Anthony Sardu, Brooklyn, N. Y. Application October 2, 1943, Serial No. 504,787 1 Claim. (01. 112-172) This invention relates to an overcast sewin machine having a needle in the form of a single circular arc and which passes completely through the fabric being stitched. An object of this invention is to provide improved means for positively holding and driving the needle, the said means comprising a plurality of cavities of circular cross-section in one side of the needle and spring-pressed pins slidably mounted in a rotatable disk or head and adap to enter said cavities for gripping and rotating said needle. Another object of this invention is to provide a needle shaft having the said head at one end thereof, and a housing enclosing the head. The head has a circular groove of a depth adapted to receive the needle to approximately one-half of its thickness. A cover has a circular groove for receiving the other half of the needle; means is also provided for securing the cover and housing to the frame of the sewing machine in a manner as to cause concentric alinement of the grooves and for supporting the needle in concentric relation with the needle shaft for rotation thereby. Another object of this invention is to provide a needle-plate positioned in parallel relation with the needle shaft. and havin a tongue projecting therefrom and to remove a portion of'the housing to permit the tongue to be positioned inwardly of the housing, clear of the path of the needle, and the needle to pass around the tongue. Another object of this invention is to provide a housing cover having a cut-out portion in alinement with the cut-out portion in the housing and to provide a needle plate positioned in a horizontal plane and adapted for supporting fabric in position for the needle to pass through an edge thereof, the cut-out portion of said cover forming a guide for the fabric. Another object of this invention is to provide cam means positioned inside said housing and adapted to release said pins successively from said needle prior to the approach of its sharp pointed end to the needle plate to permit successive portions of said needle to pass through said fabric while being rotated. Another object of this, invention is to provide four-motion feeding means in coacting relation with said needle actuating mechanism to cause simultaneous overcast stitching and feeding. With the above and other objects in view, the invention 'will be hereinafter more particularly described, and the combination and arrangement of parts will be shown in the accompanying drawof thehousing H has a circular portion 2|. ings and pointed out in the claim which forms' part of this specification. Reference will nowbe had to the drawings, wherein like numerals of reference designate corresponding parts throughout the several views, in which: Figure 1 is a side elevation of the sewing machine, partly broken away to show the interior thereof. Figure 2 is an end view showing the front portion of the sewing machine shown in Figure 1. Figure 3 is a cross-sectional view, the section being taken as on line 3-3 in Figure 8. Figure 4 is a front elevation of the needle. Figure 5 is a fragmentary perspective view showing a schematic cam and needle-gripping pin arrangement. 7 Figure 6 is a fragmentary top plan view of the cam and needle gripping pins. Figure '7 is a front view of the housing and head or carrier for the needle-gripping pins. Figure 8 is a front view of the housing and threading door, on an enlarged scale. Figure 9 is a plan view of the cloth and needle plates, and a stitched fabric strip. Figure 10 is a plan view of four-motion actuating mechanism for the feed-dogs. Figure 11 is a side elevation of the feedin mechanism shown in Figure 10. Figure 12 is a fragmentary cross-sectional View of the mechanism shown in Figures 10 and 11, the section being taken as on line I2-I2 in Figure 11. In the illustrated embodiment of the invention, the numeral It] indicates a sewing machine comprising a fixed hollow box-like frame I I ha= ing a main drive-shaft I2 mounted in the lower portion thereof, the drive-shaft I2 having a gear I3 secured thereon. An idler shaft I4 is rotatably mounted in the frame I I above the shaft I2 and carries a gear I5 which is in intermeshing relation with the gear A needle shaft I6 is rotatably mounted in a housing H at the front end of the frame I I. The needle shaft I6 is in right-angular relation with the idler shaft I4. A bevel gear I8 secured to the idler shaft I4 is in intermeshing relation with a bevel gear I9 secured to the needle shaft I6. The housing I! is secured to the frame I I by screws 2!). One end A coverEZ having a circular portion 23 of the same periphery as the circular portion 2| of the housing I! is secured to the housing I! by screws 24. As shown on an enlarged scale in Figure 3, the arcuate needle 25 is rotatably mounted in a circular groove 26 in a disk-shaped enlargement 2'! at one end of the needle shaft IS. The diskshaped enlargement 2! is enclosed by the hollow circular portion 2| of the housing ll. It will be noted that the needle 25 is also rotatably mounted in a circular groove 28 in the circular portion 23 of the cover 22. It is to be noted that the needle 25 has cavities 33 positioned crosswise of the needle and that shoulder pins 3| having pointed ends 32 slidably mounted in the disk-shaped portion 21 of the needle shaft it, are resiliently pressed by coil springs 33 into the cavities 3B and into engagement with the needle 25. For the purpose of this invention, the shoulder pins 3| must be released successively from engagement with the needle 25 prior to the approach of the sharp pointed end 28 of the needle to a cloth plate 43 having a horizontally positioned work supporting surface. I provide an arcuate cam Ill fixed to the end. wall 4 .2 of the housing ll. The cam 41 has a sharp end 43 which successively engages-collar-shaped outer ends 38' of the pins 31' and pulls the pins in a direction parallel with the shaft [6. Each shoulder pin and spring 33 is mounted inside an aperture 3 3 in the disk-shaped portion 27 of the needle shaft it. I provide apertured disks 35, Figure 6, which are suitably mounted in the reduced end portions 36 of the pins 3!. Rivets 3'! hold the disks 35 fixed to the outer surface of the disk-shaped. portion 27. In the assembled position shown in Figure 6, the diskshapedouter end 38' of the shoulder pin 3! is in spaced relation from the vertical. face 44 of the disk-shaped portion 2? a distance suificient to cause disengagement of the pins- 31, one at a time, from the needle 25, prior to the approach of the needle cavities- 3B; 36, to the cloth plate or work supporting base 46. It is to be noted that the spaced relation of the collar-shaped outer ends 38 of the shoulder pins M from the rear face 44 of the disk-shaped portion 2.?- is such. as to permit each collar 38 to engage the sharp. end 43 of the stationary cam l. When the collar (53 reaches the mid-portion of the cam, the pin St is pulled out of engagement with the needle. During the time the collar remains in contact with the cam, the pin remains out of engagement with the needle; The moment the collar passes the cam, the pin is instantly forced back into engagement with the needle by the spring 33. In the embodiment of the device shown in Figures 4 to '7 inclusive, the needle 25 used therewith has two cavities 30 for engagement with two pins 3|. Under practical conditions where heavy material is to be penetrated by th needle, three cavities 3G and three pins 31 may be employed so as to provide two pins in engagement with the needle while on pin is out of engagement. As shown in Figure 8, the annular cover 23 on the housing I! (Figure 3) has a threading door d5 pivotally mounted on a pin 46 secured in ears 4'! integral with the housing cover 22. The door 4-5 has a threading aperture 48 therethrough. The aperture 48 is positioned in the axis of rotation of the needle 25 to permit a thread passing through the aperture into the opening within theannular cover 23 to follow the needle during its rotation. It is to be noted that the needle thread is at the central portion of the axis of the orbit of the needle and that an end of the thread is threaded positioned in parallel relation and extend from the front to the rear of the machine. The feed bar 53' adjoins an end face of the frame ll. At the rear; each feed bar is bifurcated to provide rectangular openings, the opening in the bar 53 being numbered 55 and the opening in the bar 55 being numbered 56. The openings 55 and 56 receive in sliding engagement a rectangular block 51', which is rockably mounted upon a pin 58.1ixed in the frame I I. At the front, each feed bar is bifurcated to provide rectangular openings, the opening in the bar 53 being numbered 60 and the opening in the bar 54' being numbered GI. The openings 68 andtl receive in sliding engagement a rectangular block 62 which is mounted on an eccentric portion 63 of the shaft l2 and is vertically movable to lift the feed-dogs. At the end adjacent the eccentric portion 63, the main shaft [2 has a reduced stem 55 which is concentric with said shaft. Upon the concentric stem 85 there are mounted two eccentrics 66 and 67 keyed to the stem by a key 68. The eccentrics 66' and 6'! impart horizontal motions to the feed-bars 53 and 54, motion being transmitted through a link connection 69 between the eccentric 63 and the feed-bar 54, and a link connection '2'!) at one side of the link 69, between the eccentric 57 and the feed-bar 53. The forward ends of the links 69 and ill encircle their respective eccentrics S5 and 61, and at the rear ends are pivotally secured to their respective feedbars by bolts H and 12 which extend from the feed-bars parallel with the shaft 2. The bolts H and i2 serve to clamp sleeves T3. '54 against the feedbars. The sleeves form pivotal supports for the rear ends of the links 68, It. The link 78 has an elongated opening through which the bolt 12 and sleeve i4 pass without interfering with the movements of the link 6'9. In operation, the eccentrics 6S and ii! impart horizontal motions to the feed-dogs 5!, 52'. The eccentrically actuated block 52 effects vertical movements to the feed-dogs. Two cooperating four-motion feeding means are thus provided, each of which may operate in all its movements independently of the other. By giving the rear feed-dog 52 a greater amount of horizontal movement a stretching of the fabric may be eifected. By giving the forward feed-dog 5| a greater amount of horizontal movement a gathering of the fabric may be effected. The feed-dog 5| operates in advance of the needle 25 and the feed-dog 52 operates in the rear of the needle. A presser-foot 80 is carried by a presser-bar 8 l whichisslidably supported in the sewing machine head 82. In operation, a thread 83 is passed between thread tension discs 84 and then through the threading aperture 48 in the threading door 45. The thread then enters an aperture 85 in the needle 25, then passes through a concealed arcuate groove 86 in the interior of the needle and finally emerges through an aperture 81 near the pointed end 29 of the needle. Upon rotation of the pulley 89 the needle 25 is rotated. The needle carries the thread 83 through an edge portion of fabric 99 lying horizontally upon the cloth plate 40. The needle then passes round a tongue 11 in the needle plate 18. Repeated actuation of the sewing machine causes the feed-dogs 5| and 52 to impart a feeding movement to the fabric for every stitch and, as best shown in Figure 9, there is formed a continuous row of overcast stitching 9| along an edge of the fabric 90. As shown in dotted lines in Figure 2, the upper portion of the presser-bar 8| has a reduced portion 92 which carries a coil spring 93. The upper end of the spring is housed in a cavity in the lower portion of a tubular threaded member 94. The lower portion of the spring 93 rests upon an enlarged lower portion of the presser-bar Bl. The threaded member 94 may be adjusted to cause the presser-foot 80 to bear upon the fabric lying upon the cloth plate 40 with a desired feeding pressure. A lifting lever 95 is slidably mounted at the rear of the head 82 and carries a screw 96 by means of which the lever is secured to the presser-bar 8 l. The operator raises the lever, and presser-bar, and presser-foot to permit the manipulation of the fabric lying between the presser-foot and the needle plate 18. As shown in Figure 1, this machine comprises a controllable lubricating system 91 shown in my Patent No. 2,202,817. This system comprises wicks 98 lying in an oil reservoir 99 and extending to parts to be lubricated, such as the gears l3, I5 and bearing for the shaft 14, etc. An oil drain valve I90, disclosed in my said patent, maintains a predetermined oil pressure inthe oil reservoir. An oil storage chamber I] and a pump (not shown) serve to provide a constant circulation of oil during operation of the sewing machine. As shown in Figure 2, the lower portion of the head 82 is broken away to show the presser bar 8| having a key I02 which is slidably mounted in a slot I03 in a bushing I04. The slot I03 terminates in a circular cavity I05 above the slot. The operator may thus raise the foot 80 so that the key I92 enters the cavity 195, when it is possible to swing the presser-foot 89 towards the rear or to the left of the machine to provide a clear space in front of the threading door 45. As shown in Figure 9, it will be seen that the stitching 9| is straight on the top of the fabric, while the stitching below the fabric is inclined. It is to be noted that when it is desired to make inclined stitching on the top or normally exposed surface of the fabric, that the said surface is placed up side down on the cloth plate 40. It is thus possible to stitch straight stitching or inclined stitching as desired on any surface of the cloth. In accordance with the patent statutes I have described and illustrated the preferred embodiment of my invention, but it will be understood that various changes and modifications can be made therein without departing from the spirit of the invention as defined by the appended claim. I claim: In a sewing machin having a stationary frame, a needle shaft, a horizontally positioned work supporting base fixed to said frame and in line with the axis of said needle shaft, a rotatable needle in the form of a semi-circular arc and having a threading passageway in a portion of its arcuate body, and an opening at each end of said passageway, permitting passage of a thread through said passageway, means for causing rotation of said needle, a needle plate positioned parallel with said needle shaft and having a tongue projecting therefrom, said needle being movable between said tongue and the body of said needle plate, said needle plate being adapted to support fabric thereon in a horizontal position, resiliently contacting thread tension disks mounted above said work supporting base, a stationary threading door mounted on said frame in spaced relation from said needle and in parallel relation with the plane of rotation of said needle, said door having a threading aperture in alinement with the axis of said needle, said axially alined door aperture permitting a continuous supply of thread to be fed to said needle in a conical orbit during rotation of said needle. ANTHONY SARDU.



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