US1978917A - Sewing machine - Google Patents

Description

Oct. 30, 1934. c. c. STORY ET AL SEWING MACHINE Filed Feb. 25, 1935 2 Sheets-Sheet l c. c. STORY ET AL 1,978,917

SEWING MACHINE Filed Feb. 25. 1933 2 Sheets-Sheet 2 WVE/VTUES n '1 11 II.

Oct. 30, 1934.

Patented Oct. 30, 1934 PATENT OFFICE SEWING MACHINE Clifton 0. Story and Wilfred G. Story, Beverly, Mass.

Application February 25, 1933, Serial No. 658,489

10 Claims. (01. 112-162) This inventicn'relates to sewing machines, useful particularly in uniting the edges of Webs of cloth in the manufacture of textiles but having novel features of more general application.

5 In machines of this type, it is customary to superpcse the edges of the webs to be joined and unite the edges by a seam overcasting the edges, and in forming such a seam it is necessary to engage the thread and carry a loop from one side thereof about the lapped edges and into the path of the needle on the other side of the work. An important feature of our invention consists in an improved loopermechanism for carrying out this portion of the stitching operation. As herein shown, we have provided an elongated looper movable alternately above and below the work, acting to engage a loop in the thread at one side thereof, carry'the loop over the lapped edge and into the path of the needle on the other side of the work. As will hereinafter appear, we have provided novel mechanism for reciprocating the looper transversely to the path of the needle and for also raising and lowering it in its alternate advancing movements, this mechanism being sim- 25 ple in construction, accurate and reliable in operation-and adapted for long and continuous use without appreciable wear. While the arrangement of the looper and its actuating mechanism is believedto be novel, it possesses also novel features of construction and in its relation to other parts of the machine,for example, the thread hook which is formed as a part of the presserfoot and over which the thread of the loop is rendered by the forward movement of the looper above the .5'work.

. The particularmachine herein shown is adapted to includea novel four-motion work feeding mechanism, which-is hereinshown as adjustable in a novel manner to. regulate the spacing of the 49 loops of the seam. We provide alsoa n'ovel edge trimming mechanism comprising a rotary'cutter which is driven from the main shaft of the machine and cooperates with the anvil to trim the upper lapping edges of the web before they arrive at the sewing point.

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings, in which Fig. 1 is a view of the machine in perspective with portions of the frame broken away;

Fig. 2 is a view of 'themachine in front eleva- W tion, also with portions of the frame broken away; Fig. 3 is a View in perspectiva on an. enlarged.

scale, of the operative instrumentalities of the machine in position upon the work;

Fig. 4 is a fragmentary view in perspective of the forward part of the machine; and

Figs. 5, 6 and 7 are views, on an enlarged scale, showing different positions of the needle and looper with respect to the presser foot and work.

In the embodiment of the machine herein illustrated, a box-shaped frame 10 is employed in which is journaled the main shaft 12 having a driving pulley 14 at its rear end and a pair of eccentrics secured thereto in the rear of its forward bearing. Of these, the eccentric 16 serves to actuate the needle bar and for this purpose is arranged to reciprocate an eccentric rod 18 adjustably connected by a screw 20 at its upper end to a crank arm 22. The crank arm is secured to the rear end of a horizontal shaft 24 journaled in the forward part of the frame and having at its forward end a rocker 26 carrying a forwardlyprojecting pin 28. The pin 28 is arranged to slide in a cam groove formed in the inner face of the head 30 secured to the needle bar 32, which is guided for vertical reciprocation in the forward part of the machine frame and carries at its lower end the needle 33 in the usual manner. It will be seen that in the rotation of the shaft 12 the rocker 26 is oscillated through the mechanism just described and the cam pin 28 carried back and forth and, in cooperation with the cam slot in the head 30, causes vertical reciprocation of the needle bar 32. A vertical presser bar 34 is also mounted in the forward part of the machine frame, being arranged to pass through an adjustably threaded sleeve 36 and having a collar 40 between which and the sleeve 36 is interposed a compression spring 38, tending at all times to force the presser foot 44 into engagement with the work. A hand lever 42, pivotally mounted upon the frame, is provided for temporarily lifting the presser foot to facilitate the introduction or removal of work from the machine. The presser foot is slotted at its lower end, providing an arm or chaining finger 46, which will be hereinafter termed the thread hook since the threads of the loop are rendered over it in the forward movement of the looper, as will presently be explained.

Secured to the forward part of the machine frame 10 is a horizontal work table 48, cut out to receive a hardened anvil plate 50. The anvil plate is formed with a shearing edge cooperating with a rotary shearing device 58. This comprises a corrugated disk which is mounted on the forward end of a short horizontal shaft 56 mounted in the forward part of the machine frame and having at its rear end a gear 54 which meshes with a gear 52, shown in Fig. 4 as secured to the main shaft 12 in advance of the eccentric 16. It will be understood that as the work is advanced from right to left across the work table 48 and the anvil 50 its inner edge is sheared in a straight line just prior to the formation of the stitch therein. i

The work feeding mechanism which cooperates with the presser foot in advancing the superposed edges of the two webs will now be described. This comprises a corrugated feeding foot 64 which is movable transversely in a slot formed in the anvil 50 and is carried by a vertically-disposed feed plate 62. The feed plate 62 is suspended beneath the table 48 upon the forward part or" the machine frame by spaced members. One of these comprises an eccentric 60 which is formed on the for- Ward end of the main shaft 12 and which passes into a slot, 61 in. the feed plate 60. The other is an eccentric stud 68 which is threaded into the machine frame and passes through .a slot 66 in the feed plate 62. Rotation of the eccentric 60 oscillates the feed plate about the eccentric stud 68 as an axis, raising and lowering the feeding foot 64. A downwardly-extending lever arm 70 is pivotally mounted upon the feed plate '62 by means of astud 72 locatedabout midway between the points of suspension of the plate; The lever arm 70 is connected by a link 74 to a pin 76 projecting from the eccentric 60 and disposed eccentrically with respect to the axis of the shaft 12. In the rotation of this shaft, accordingly, the lever arm 70 is oscillated. The lower end of the arm 70 is wedge-shaped and arranged to oscillate between'stop pins '79 which project outward ly from a feed adjusting plate 78, adjustably-secured to the frame 10 by screws 80. The oscilla tion of the end of the lever between the stop pins '79 is idle but when it engages the left-hand pin 79,

for example, its movement is arrested and there-.

upon the lever will swing toward the left about this point of contact as a fulcrum and carry the I feed plate 62;bodily toward the left. 7 When the lever is swung in the opposite direction, idlernotion occurs until it engages the right-hand stop pin '79, whereupon its point of contact with this becomes a fulcrum and the upper end of the lever is swung toward the right, carrying the feed plate in the same direction. The eccentric'fifl and the eccentric pin '76 are timed so that movement of the feed foot toward the left occurs when. the,

feed plate is swung upwardly by the eccentric 60 and movement of the feed platetoward the right occurs when the feed plate is swung downwardly.

The looper mechanism will now be described- This includes a looper rod 82 guided at its rear endfor horizontal reciprocation forwardly and rearwardlyinthe machine by an elongated tube 84 set in the rear portion of the machine frame 10. The looper rod is jointed by means of apin 86 which extendsoutwardlyand constitutes part of the operating connection for reciprocating the rod. To this end,-the pin 86 extends into a vertical slot formed in the lower end of a lever 88 arranged to oscillate. about a stud 90 projecting from' the machine frame. The lever 88 has a 1 short angular arm 89 extending outwardly therefrom and connected through a universal joint with the upper end of an eccentric rod 90. At its lower end'theeccentric rod 96 surrounds an eccentric 92 on a short horizontal shaft 94, which is journaled in the rear wallof the machine frame 10 and a bearing bracket 96 bolted to the bottom of the frame. The shaft 94 is rotated by a pinion 98 thereon which meshes with a corresponding gear 99'on the main shaft 12. It will be seen, therefore, that rotation of the eccentric 92 through the connections just described imparts oscillation to the lever 88 and a reciprocatory movement to the looper rod 82 in timed relation to the reciprocation of the needle bar 32. The rear section of the looper rod is guided for reciprocation in a straight line path by the tube 84, as already explained, and is also free to turn or twist within the tube about its longitudinal axis to a limited extent, and to permit such twisting movement the lever 88 is slotted for its connection with the pin 86.

At its forward end the looper rod 82 is pro- 'vided with an enlarged portion 100 of rectangular cross section and perforated for the sake of lightness. This is received between the arms of a forked lever 102 journaled to swing about a stud 104 projecting rearwardly from the forward portion of the machine frame, as best shown in Fig. 4. The lever 102 is oscillated about its axis by an eccentric rod 106 and this, in turn, is operated by an eccentric formed on the shaft 12 in advance of the eccentric 16, already mentioned. The eccentric rod 106 is provided with apvertical slot through which extends a stud 108 from the arm 102, the arrangement being such that a lost motion operating connection is pro.- vided whereby the'arm 102 may remain at rest during the portion of. the cycle when the looper is advanced above or below the work. The eccentric, however, acts to swing the arm 102 and.

raise or lower the looper when itis retracted. The arms of the lever 102 extend outwardly beyond the portion 100 of the looper rodbetween ad justable blocks 110 and .112, mounted inside the forward portion of the machine frame. By properly setting these blocks, the upper and lower limits of the throw of the arm 102 are adjustablyand positively determined.

The looper head is threadedinto the forward end of the portion 100 of the looper banbeing maintained in position by a set nut 114. It comprises a throat 116, a hooked upper finger 118 and a curved lower finger 119. The thread of the loop is drawn over-the throat 116' when the looper head is advanced above the work anda loop of thread is pulled from'the needle by the hooked finger 118 when the looper head is moved rearwardly beneath the work.

The stitch forming cycle will now be described with reference particularly to Figs. 3 and 5 to 7. The superposed webs '120 and 122 are positioned upon the work table 48 while the needle 33 is elevated, asshown in Fig. 5. When the machine is set in operation, the needle at once descends through the slot in the presser foot and the anvil 50, carrying the thread through the work and reaching the position shown in Fig. 6. The looper meanwhile has been advanced and when the needle reaches the limit of its down- Ward movement it is moved rearwardly, and in this movement the hooked finger 118 of the looper engages the thread adjacent to the eye of the needle. and pulls a loop of thread rearwardly, then upwardly about therear trimmed edge of the work and the thread hook 46, andthen forwardly into the position shown Fig. '7. In this operation the thread of the loop renders through the eye of the needle and is pulled forwardly over the thread hook 46 and across the upper H .pin 79 on theadiusting plate '78.

full length pulled tight but not being drawn into the yielding edge of the work. This is a feature ofimportance in the machine of our invention, insuring as it does that the loops shall all be drawn accurately to the same length and tension independently of the texture of i thecloth being stitched. In arriving at the position shown in Fig. 7, the needle 33 has been elevated and the loop is thereupon positioned, as shown in Fig. 3, so that in its next downward stroke the needle will pass through the loop. Meanwhile, the feeding foot G-loomes into "action and advances the work toward the left, carrying the loop out of the looper and leaving the looper free to recede, in readiness for the next stitch. .The operation continues in this manner across the full width of the web, whereupon the thread is out and the work removed.

'The looper head comprises the upper hooked finger 113 and the lower finger 119 spaced somewhat from each other by the throat 116. As herein shown, mechanism is provided for twisting the looper headso that it occupies a different angularposition in upper position, as shown in 1 Fig. 5, from that which it occupies in its lower position, in Fig. 6. This is for the purpose of bringing the hooked finger 118 into position to engage the needle thread and pull a loop therefrom in its lower position, and into thread disengaging position when the looper is located in its upper position and has carried the loop into the path of the needle. In passing from one position to the other, the looper is so positioned that the two fingers cooperate to lock the thread therein against the possibility of premature dis engagement. As has already been noted, the looper rod is provided with a rectangular section 100 and this is engaged between the jaws of the lever 102. The inner edges of these jaws are i disposed in parallel relation and as the lever is oscillated their angular position changes, that is to say, when the lever 102 occupies its upper position the jaws are substantially horizontal, as shown in Fig. 4, but when the lever is rocked T into its lowermost position the jaws are downwardly inclined 15 or 20 degrees. This oscillatory motion of the lever 102 about the axis of the stud 104, accordingly, imparts a twisting motion to the rectangular section 100 of the looper rod and causes the looper head to twist about a longitudinal axis, in a manner already explained.

The'distance between the loops formed in the stitching operation depends upon the amplitude of the feeding movement as determined by the transverse motion of the feeding foot 64, as already explained, and this in turn depends upon the oscillation of the lever arm '70 and the amount of lost motion occurring between it and the stop The adjusting plate is provided with vertical slots and. adjustably secured to the frame 10 by screws 80. When it is desired to increase the amplitude of the feed, these screws may be loosened and the adjusting plate "78 moved downwardly, carrying the stop pins opposite to the wider end of the wedge-shaped arm of the lever 70. Accordingly, in the oscillation of this arm, the pins '79 are sooner encountered and more of the oscillatory movement of the arm is imparted to the feed plate 62 and the feeding foot carried thereby.

In sone cases it is desirable to mount the stitcher for bodily movement across the web in the stitching operation and for this purpose the base of the machine frame is shown as flanged for movement in suitable guideways. The main shaft 12 is also shown as provided with a worm 130 which may mesh with the teeth of a worm wheel or gear movably mounted on a suitable carriage adjacent to the machine but not herein shown, since it forms no part of the present invention. It will be understood, however, that the worm 30 constitutes an element of mechanism for imparting a bodily movement to the stitching machine, if such use is desired of it.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is: t

1. A sewing machine having a work support, a reciprocatory needle, a thread hook arranged to lie near the edge of cloth on the work support, a looper rod guided for longitudinal and twisting movements and having a thread engaging head, means for reciprocatingthe looper rod toward and from the path of the needle rendering the thread about the thread hook in one of its movements, and separate mechanism for raising and lowering the looper head and for twisting it angularly so thatin alternate advancing strokes it passes above and below the thread hook in different angular positions.

2. A sewing machine having a work support, a reciprocatory needle, a looper movable alternately above and below the support and having a hooked finger for pulling a loop from the needle thread at one side of the support and carrying it into the path of the needle at the other side of the support, means for supporting the looper for twisting movement, and means for twisting the looper in opposite directions above and below the support to carry said finger into thread engaging position at one side of the support and into thread disengaging position upon the other side of the support.

3. A sewing machine having a work support, a reciprocatory needle, a looper rod carrying a looper and being mounted for twisting movement and also endwise movement toward and from the path of the needle and having a section of rectangular cross section, and a lever arm engaging the looper at said section and arranged to oscillate to raise and lower the rod and at the same time twist the looper.

4. A sewing machine having a work support, a reciprocatory needle, a looper rod guided at its rear end for movement in a path at right angles to the needle, means for raising and lowering the forward end of the looper rod so that it alternately passes above and below the work support, said means comprising a lever extending transversely to the looper rod and having a lost motion operating connection, and adjustable stops for positively limiting the throw of said lever.

5. A sewing machine having a work support, a presser foot having a thread hook arranged to be located near the edge of superposed pieces of cloth upon the support, a looper movable alternately above and below the thread hook and having an open throat for engaging and causing the thread to render over the thread hook in the forward movement of the looper inwardly from the edge of the cloth and across the upper face of the presser foot, and a finger for pulling a loop from the thread in the needle in the rearward movement of the looper below the thread hook.

6. A sewing machine having a work support, a reciprocatory needle, a looper rod guided at its rear end for reciprocation in a path at right angles to the needle and also for twisting movement, and having thread fingers at its forward end, and means engaging the looper rod and operating to raise and lower the thread fingers and alsov to control at all times the angular position of the forward end of the looper rod and to twist it angularly-about a longitudinal axis so that the thread fingers alternately pass adjacent to the needle above and below the work support in different angular positions.

oscillating it as the looper head'passes above and below the work support. 7

8. A sewing machine of the class described, having in combination, means for holding the work including a presser foot having a chaining finger, a stationary tubular guide, a jointed looper rod having a section arranged to reciprocate V as? and oscillate in said guide andanother section carrying a looper head and arranged to swing during such reciprocation whereby the looper head may be. passed first above and then below said chaining finger, and means acting upon said swinging section for twisting the looper head.

9. A sewing machine having a work support, a reciprocatory needle, a looper rod guided for longitudinal movement toward and from the path of the. needle, a looper head carried by the looper rod and supported for twisting movement in the machine, and'an oscillatory lever for raising and lowering the looper head and simultaneously twisting it from one position to another about its longitudinal axis. i

10.'A sewing machine having a work support, a reciprocatory needle, a looper rod movable endwise toward and from the path of the needle, a looper head supported for twisting movement in the machine, and having cooperating fingers thereon, and means for twisting the looper head in one direction above the work support and in the other direction below the work support,

wherebya loop of needle thread is first engaged, then looked into the looper head and finally disengaged. WILFRED G. STORY. CLIFTON C. STORY.

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