US2609773A

US2609773A - Thread handling mechanism for sewing machines

Info

Publication number: US2609773A
Application number: US625207A
Authority: US
Inventors: Nelson George William
Original assignee: Lewis Invisible Stitch Machine Co
Current assignee: Lewis Invisible Stitch Machine Co
Priority date: 1942-12-10
Filing date: 1945-10-29
Publication date: 1952-09-09
Anticipated expiration: 1969-09-09

Description

Sept. 9, 1952 s. w. NELSON 2,609,773

' THREAD HANDLING MECHANISM FOR SEWING MACHINES Original Filed Dec. 10', 1942 a Sheets-Sheet 1 IQVVENT s) 650/665 MAL/AM A/E av Sept. 9, 1952 a. w. NELSON THREAD HANDLING MECHANISM FOR SEWING MACHINES 8 Sheets-Sheet 3 Original Filed Dec. 10. 1942 INVENTOR. w

66055-5 14/; IA NELSON Sept. 9, 1952 s. w. NELSON 2,609,773

THREAD HANDLING MECHANISM FOR SEWING MACHINES Original Filed Dec. 10, 1942 8 Sheets-Sheet 4 IN VEN TOR.

Geo/36E Mum/v M6110 G. W. NELSON THREAD HANDLING MECHANISM FOR SEWING MACHINES Sept. 9, 1952 Original Filed Dec. 10, 1942 8 Sheets-Sheet 5 E E @2 5A 3 INVENTOR. (550E615 Mum/v A/tZJO/V Sept. 952 G. w. NELSON 2,609,773

THREAD HANDLING MECHANISM FOR SEWING MACHINES Original Filed Dec. l0, 1942 i 8 Sheets-Sheet '7 D Q wiajd 514.

INVEN TOR. 650/665 W/LZ/A/V M5450 I BY P 1952 G. w. NELSON 2,609,773

THREAD HANDLING MECHANISM FOR SEWING MACHINES Original Filed Dec. 10, 1942 8 Sheets-Sheet 8 .63 Mia. 19.

- b 47a 47 "W f I f M INVEN TOR. Gav/m5 M44 m/v /V[Z JON wfw Patented Sept. 9, 1952 THREAD HANDLING MECHANISM FOR I SEWING MACHINES George William Nelson, Cleveland, Ohio; assignor to Lewis Invisible Stitch Machine Company,,St. Louis, Mo., a corporation of Maine Original application December 10, 1942, Serial No. 468,515. Divided and this application October- -29, 1945, Serial No. 625,207 r I 1 10 Claims. (Cl. 112-254) The invention herein. disclosed relates to a sewing machine ofthe kind that effects a pre-,

determined number of stitch-forming operations and automatically stops. More particularly, the invention relates to thread handling. mechanism for such sewing machines; The present application constitutes a division of my copending application Serial No. 468,515, filed December 10, 1942, and which matured into Patent No. 2,511,367, June 13, 1950.

An object ofthe invention is to provide thread handling mechanism that is simple, durable and effective in operation. Another. object of the invention is to provide thread handling mechanism in a machine of the --kind mentioned that includes certain arrangements operative upon formation of a predetermined number of stitchforming operations to effect a severance of the thread and a pull-off of thread for the. start of the next stitching cycle. A- further object of the invention is to provide actuating mechanism for the thread handling mechanism.

The foregoing and more particular objects of the invention together with certain advantages thereof are realized in the illustrative embodiment of the invention disclosed in the drawings and described in detail below.

The drawings include:

l which is an isometric view of a. button sewing machine embodying the invention;

Fig. 2 which is a side elevation of the same, partly in section;

Fig. 3 which is a side elevation of the side opposite to that shown in Fig. 2 and sectioned in part;

Fig. 4. which is a rear end elevation of the same, partly in section;

Fig. 5 which is a fragmentary plan with a side cover open;

Fig. 6 which is a fragmentary top plan of the machine, partly in section;

Fig. '7 which is a. bottom plan of the machine;

Fig. 8 which is a sectional plan taken on the line 8-4 of Fig. 2;

Fig. 9 which is a transverse section taken on the line 99 of Fig. 8;

Fig. 10 which is a front end elevation, partly in section;

Fig. 11 which is a plan of the positioning finger shown in elevation in Fig. 10;

Fig. 12 which is a side elevation of the same taken on the line I2-l 2 of Fig. 11;

Fig. 13 which is a side elevation of the stop motion control disks;

Fig. 14. which is a section ofthe same taken on the line Ml4 of Fig. 13;

. 2 Fig. 15 which is an elevation of one of the control disks; w l 1 H Figulfi which is. an enlarged, fragmentary elevation of a detail ofa lever and its actuator;

Fig. 1'7 which is an enlarged, fragmentary elevation of a sub-assembly of the operating mechanismfor raising the button clamp; Fig. 18 which is a plan ofv the same; and Fig. 19 which isa development ofa cam.

Goneml' The drawings disclose a machine for sewing buttons, having two or four holes, on to fabrics or other materials to which such buttons may be sewn. In general, such a machine includes stitch-forming mechanism for effecting the formationof stitches successively, some mechanism for effecting relative lateral movement of the button with respect to the stitch forming mechanism, and mechanism for effecting a cyclic operation of the stitch-forming mechanism. These mechanisms are conjointly operated to effect a series ofstitches with the thread passing in successive stitch-forming operations through different holes of the button and in consequence over the portion of the button between the holes. In this manner the button is sewn or bound to the fabric. l

Commonly, the stitch-forming mechanism is the kind thatyoperates upon a single thread. To this end, .thereis provided a needle: bar for carrying the needle, and mechanism, for reciprocating the needle bar. A looper cooperates with the needle. The lower is mounted below the bed of the machine and positioned and operated. in timed relation with respect to the needle. On the downward or penetrating stroke, the needle passes. through a hole in the button and through the fabric, carrying the thread with it. At the startof the return stroke, tension on the thread is released and a'loop is cast because of the friction between the cloth and the thread. The looper catches the loop and a positioner arranges it such that on the; next succeeding, penetrating stroke of the needle, the needle passes through the positioned loop cast on thelast stroke of the needle. Thus, a seriesof stitches are formed.

Relative lateral movement of the, button-and needle to cause the needle to pass, through different holes inthe button on successive strokes may be effected by, shiftingv or. jogging the needle bar .or by shifting the button. In the machine illustrated the button is shifted. To this. end a shiftable button clamp is used and mechanism is provided for shifting the clamp in timed relation with respectjtoj the" needle. 'IThis mechaa four hole button, the button clamp is positioned to present successively the holes of one pair, and

after a predetermined number of stitches it is shifted to present the holes of the other pair of holes in the four hole button. At the end of the operation, tying stitches are effected to prevent the unraveling of the thread. For this purpose, the last several stitches are effected through the same hole in the button. If it be desired to elimihate what is termed a cross over stitch, that is a thread crossing over from one pair of holes to the other pair, in a four hole button, tying stitches are made before the button clamp is shifted and the thread is broken.

All of the foregoing mechanism is mounted in a single frame which, in the machine illustrated, includes a bed I supported on, and extending from, a base 2. A column or standard 3 extends vertically from the base. The column 3 supports a laterally extending arm 4 on the end of which there is a needle head 5. As the operator faces the free end of the arm 4, that is, the needle head 5, it is appropriate to designate this end of the machine as the front of the machine, and therefore, the column 3 is at the rear of the machine.

Stitch-forming mechanism The stitch-forming mechanism includes a vertical needle bar 6 (Figs. 1, 2 and 3) that is slidably mounted in spaced hearings in the needle head 5. The needle bar is, in the usual manner, constructed at its lower end, to receive and retain a needle 1 having the eye at the point thereof. For the purpose of effecting stitches, the needle bar is reciprocated vertically to carry the end of the needle from a point above the bed of the machine to a point below the bed of the machine. To this end, there is (Fig. 2) a lever 8, mounted on a pivot 9 extending into and journaled in the arm 4 of the frame. One end of the lever receives a plunger ID that is slidably mounted in the lever and that has a head i I through which the needle bar extends and is pivotally secured.

The other end of the lever is secured through a ball and socket connection to one end of a connecting rod l2 (Figs. 2 and 4), the other end of which is connected to the strap 13 (Figs. 4, '7 and 8) of an eccentric mounted on a main or power shaft I4.

The ball and socket connection (Figs. 2, 4 and 6) includes a pin I20. having a ball 12b on the end thereof. The pin extends through an opening provided therefore in the arm. Two such openings are provided, the one in which the pin is shown as being secured and another He spaced therefrom towards the pivotal axis of the lever. By shifting the pin 12a to the hole l2c a change in the stroke of the needle may be effected for different fabrics. In a machine constructed in accordance with this invention, a change in stroke may be made for example from a stroke of one and five-eighth inches for light work to a stroke of one and three-quarter inches for heavy work. The change from one length of stroke to the other is taken up upwardly such that the point of the needle moves to the same lowermost position irrespective of the length of the stroke.

The power shaft [4 (Fig. '7) extends transversely of the base of the machine, through both nection, the looper shaft is continuously rotated,

' in the direction of the arrow (Figs. 2 and 7) as the needle bar is reciprocated. The end of the looper V. "shaft. extending forwardly through the bearing bracket Isis reduced in diameter and is received in a fixture 2!) which is secured to the looper shaft by set screws. In an axial opening in the opposite end of; the cam fixture, a stub shaft of a hook-shaped looper 2| is received and secured therein, for rotation therewith, by set screws.

As the thread loops are thrown at the start of the return stroke of the needle the rotating looper takes the loop, twists it through one hundred and eighty degrees and holds it until the next succeeding penetration of the needle after which by virtue of the position to which the hook-shaped looper has rotated, the loop is cast off the looper. To position the loop held by the looper, there is a positioning finger 22 (Figs. 10, 11 and 12) arranged to cooperate with the looper. This positioning finger is mounted on a yoke 23 that ambraces a three point cam 24 on the cam fixture 2D. The yoke has oppositely extending lateral arms 25 that are received in and slidable in grooves provided therefor in and transversely of the bed. The positioning finger is formed on a plate 26 that is received in a groove in the top of the yoke extending parallel to the looper shaft. The plate is held in a slot in the yoke by a dowel pin. The positioning finger lies directly below a needle plate 2'! which, when removed, provides access to the positioning finger, supporting yoke and cam fixture. It will be seen (Fig. 10) that when the looper shaft is rotated the yoke and in consequence the positioning finger are reciprocated transversely of the path of the needle. In this way the positioning finger takes the loop held by the looper and positions it to position the loop for proper correlation with the point of the looper and to receive the needle on the penetrating stroke of the needle.

Associated with the positioning finger plate there is an adjustable needle guide. This consists of a strip 28 having a downward extension 28a shaped as shown (Figs. 11 and 12). The strip 28. is received in a longitudinally extending slot in the forward end of the bed and has a slot 28?) therethrough through which a machine screw 280 extends to secure the guide to the bed. The positioning finger plate 26 has a downward extension 26a which forms a needle guide slot with the needle guide. The needle guide like the positioning finger are below the needle plate 21. I

For holding a button in position during the stitching operation there is provided a button clamp (Figs. 1,2, 3 and 8). This button clamp is secured to a bracket 29 at the forward end of the bracket. The rear end of the bracket 29 has spaced depending lugs 30 that are pivotally secured by means of a pivot pin 30a to the lugs 3i extending from a lever 32. This lever 32 is for vibrating and shifting the button clamp and for this reason, it is pivotally secured to the bed of the machine by a pivot screw 33. The head 34 (Fig. 9) of the pivot screw engages the under width than the width of the slot 35. A bushing 31 is received in the slot 36 and engages the upper surface'of the bed I. In this bushing a cylindrical extension on a nut 38 is received, the nut being threaded on to thepivot screw. Be tween the nutrandthe lever, there is an indicator bracket 39 having an indicator point 40. The bracket-is provided with oppositely depending ears 39a that extend into the slot 36 and prevent the indicator bracket from turning on the pivot. The indicator point extends over an indicator plate 4| secured to the bed and extending parallel to the slots. This indicates the throw, or extent of 'vibration or, the clamp for various positions of the pivot 'along the slots.

The lever 32 is vibrated about the pivot screw 33 to cause a button held by the button clamp to present successively the holes of a two hole button or the pair of holes of a four hole button to the needle as the needle is reciprocated. For this purpose; the lever includes an arm 42 (Figs. 2 and 8) that extends rearwardly of the lugs 3|, into the column 3 just above the base and over the top plate-43 of the base. To the end of the arm 12, of the lever 32, there is pivotally secured one end of a link 46, and the other end of which is pivotally secured to one end of a lever 45. The other end of the lever 45 ispivotally secured tothe-plate 43 by a pivot screw 45a. Intermediate the ends of the lever 45 and adjacent the end to which the link 44 is connected, a cam follower pin 46 is threaded into the link 44. This pin extends through the link 44, a slot provided therefor in the plate 43 and into the track of a positive, sinuous cam 41. The track (Fig. 19) of the cam is formed in the edge of the cam and the cam is mounted on a horizontal cam shaft 48, journaled in bearing lugs formed on the inner surfaces of the sides of the base.

The cam shaft 46- (Figs. '7 and 8) to which the cam 31 is secured for rotation therewith is driven from the looper shaft IT. The drive is through two helical gears, one 45 secured on to the looper shaft l1 and the other 50 secured on the cam shaft 48. Thus, it will be observed that as the cam 41 is rotated the lever 45 is vibrated about its pivot 45 and through the link 44 vibrates the lever 32 about the axis of the pivot screw 33. As the pivot screw 33 constitutes the fulcrum of the lever 32, a shifting of the pivot screw along the

slots

35 and, 36 will vary the throw of the button clamp. v

In order to accommodate a four hole button in a machine in which the needle moves in afixed path, it is necessary to be able to shift the button clamp supporting lever longitudinally, that is in a forward and rearward direction. In this way first one pair of the holes of a four hole button may be successively presented to theneedle and then the other pair of holes. In the machine illustrated this longitudinal movement of the button clamp supporting lever 32 is accomplished by the following mechanism (Figs. 2 and 8): One end of a control lever is pivotally secured to the arm 42 of the lever 32 through a link cm. This control lever has a resilient extension 52 extending through the column and out at the rear of the column, providing at the rear of the machine a-finger piece by whichthe lever maybe adjusted. Extending fromthe'side 6. edgeofthe lever 5|, there is a lug 53, through which a pivot pin 54' extends; This pivot pin is securedto a yoke 54a which embraces an elevated, arcuate central rib 55 extending from a lever bracket-56 of the bell crank type. The lever 53 is pivoted to the plate 43 through a countersunk pivot screw 51-. An arm 58 of the l'ever carries, adjacent-the end thereof, a cam follower "pin "59 which is secured-therein and extends into the track of a positive track cam 66 mounted 'on the cam shaft 48. The cam 48 has a track in the edge thereof, one half of which is offset axially'with respect to the other half. Between the lug 53 and the end of the lever 5i that is pivoted to the lever 32, one end of a link 3| is pivotally connected to the lever. The other end of the link 6| is pivotally secured to the plate 43 in line with the pivotal axis of the lever bracket 55. a i

From the 'foregoingit will be apparent that as the cam 6|] rotates, and the cam follower pin 53 meets an ofisetin the cam track, the bracket lever 55 will be moved about its pivotal axis. In the position illustrated in Fig. 8, the lever 5| will be moved longitudinally, and by virtue of the link 6|, thelever 32 will be moved longitudinally in a straight line movement. The amount of movement of lever 32 will depend upon the distance between the pivotscrew 51 and the pivot pin 54.

If the lever 5| is shifted such that the pivot pin 54 is directly over the pivot screw 51, there will not be any longitudinal movement of the levers 5| or 32 when the lever bracket is moved. This is the position of the lever 5| for sewing a two hole button. For a four hole button the lever 5| is shifted away from this position an amount depending upon the size of the button or rather the distance between the button holes.

The extent of the longitudinal shifting of the lever 32 is proportional to the distance the pivot pin 54 is from the pivot 51. On the rear of the standard 3, there is secured a marked indicator 52a having marked thereon distances of movement of the lever 32 for various positions of the extension 52. The extension 52 is provided with anarrow 52b for this purpose. indicator 52a and the extension 52 may serve to hold the extension 52 in any set position.

As the clamp vibrating cam 41 and the clamp shifting cam 3|] are secured on the same shaft, the same number of stitches, for a given operation of the machine (one revolution of the cam shaft) will be made whether a two or four hole button is being sewn, except for the modification of the mechanism as hereinafter described. In the case of a four hole button one half of the number of stitches will be made in each pair of holes.- The track of the cam 41 is developed in Fig. 19, from which it will be seen that at spaced intervals, such as at 41a, 411), there is a straight portion. As the cam follower pin 46 rides in these portions of the cam two or more stitches are made in the same hole to effect tying stitches. Fora four hole button such tying stitches are made just before the lever is shifted and at the end of the sewing operation.

Stop motion revolution of the cam shaft when two hole buttons are being sewn, or aftera fullrevolution of the cam shaft when :four hole buttons are being Detents on the 7. sewn. In this way twice the number of stitches are used for a four hole button, each pair of holes receiving the same number of stitches as a two hole button.

Machines of this kind operate at comparatively high speed and the momentum of the mechanism must be absorbed quickly and the machine stopped with the needle withdrawn in its uppermost position. This is accomplished in the machine illustrated by absorbing the momentum by springs which also serve to center the driving shaft and so stop the machine in the desired position of the mechanism. The main drive shaft I4 (Figs. 4 and is driven through a pulley 62 that is free on the end of the shaft. On its outer side the pulley engages, through a thrust bearing, a spherical-sector head 63 which is engaged by the wedge-shaped end of a lever 64. On its inner side, the pulley is provided with a frustroconical surface 65 which is positioned to cooperate with a complementary frustro-conical surface 66 of a disk 61. The disk 61 is also free on the shaft I2, but the diameter of the shaft receiving hole through the disk is somewhat greater than the diameter of the shaft so that the disk is free to float, that is, move a limited amount in all lateral directions. Adjacent the disk 61 and secured on the shaft for rotation therewith, there is a heavier or thicker disk 68, having a hub 69 between which and the shaft bearing there is a thrust bearing 10. The disk 68 is secured to the disk ti 3 for rotation therewith by screws II threaded into the disk 68 and having elongated heads. extending through openings in the disk 6'I.'

The openings in the disk 61 for the heads of the screws II are larger in diameter than the heads of the screws so that they do not interfere with the float of the disk 61. The pulley which is slidable on the shaft I2 is normally spring pressed by a spring I2 away from, and out of driving relationwith. the disk 67.

The disk 98 (Figs. 2, 4 and 5) forms a part of the stop-motionmechanism. It cooperates with a resiliently'centered plunger I3 having a lug 14 extending therefrom. Within a circumferentially extending slot in the disk 68, there is pivotally mounted a latch I6 on a pivot pin 11. The latch '65 is springpressed by a spring I8 to a position in which it extends beyond the peripheral edge I9 of the disk 68. The latch I6 is provided with a transverse slot or notch 89 which is of suificient width to receive the lug I4 on the plunger 13.

Theresiliently centered plunger is slidably mounted in and extends through a pivotally mounted housing 84. The housing is divided at the longitudinal center by a partition 85 which constitutes a bearing for the plunger and an abutment for springs 86 and 81. The spring 86 acts between the partition 85 and a shoulder formed by an enlargement 88 on the plunger. The spring 31 acts between the partition 85 and a nut 39 threaded on to the end of the plunger. The housing 84 has a bracket 90 formed thereon which is secured to a shaft 9| extending between and through the side walls of the base in which it is journaled. An arm 92 extends from the bracket to and a spring 93 engaging the arm 92 and a pin 94 in the side of the base acts to resiliently urge the housing in a direction to cause the lug- 74 to engage in the notch 80 in the latch iii. The housing 84 may be moved to release the lug 74 from the notch 80 through a foot treadle (not shown) connected to an extension 95 at the rear'of the housing.

en thelug I4 israised out of the notch 75, the lever 64, which is secured on to the end of the shaft 9|, is raised. The wedge-shaped end 98 of the lever acting on the spherical sector head presses the head inwardly. The head 63 is formed on a plunger slidably mounted in the end of the shaft I4 and upon being moved inwardly forces the pulley into driving relation with the floating, frustro-conical disk 61. The pulley is continuouslydriven by an electric motor (not shown) sothat when the lug I4 is out of the notch 80, the shaft I4 starts to rotate in the direction of the arrow (Figs. 2 and 3). When the foot treadle is released, the lug rides on the edge of the disk 68.

With this arrangement, without the control hereinafter described, the machine would continue to operate for one revolution of the drive shaft I4. As the lug I4 approached the latch I6, it would depress the latch, permitting the housing, under the action of the spring 93 to move about its pivot. This action serves to release the cone clutch, and when the lug I4 abuts against the edge of the notch the clutch is completely released. The latch returns to its normal position when this occurs and the lug is held in the notch. The resiliently centered plunger absorbs the momentum and the rebound without undue shock to the mechanism.

As the cam shaft 48 is geared to the drive shaft in a relation such that the drive shaft makes sixteen revolutions for each revolution of the cam shaft, controls are provided so that the stopmotion mechanism, above described, may actuate either after eight or sixteen revolutions of the main shaft,-eight revolutions being sufficient for a two hole button and sixteen being required for a four hole button. In the machine illustrated this control acts upon the shaft 9|.

On the opposite end of the shaft 9| (Figs. 3, 8 and 13) there is secured a lever 99 which carries a cam follower I00. The cam follower I00 is positioned to engage the edges of control disks NH and I02 mounted on .the cam shaft 48. The disk IOI is provided with a hub I03 through which it is secured to the cam shaft 48 for rotation therewith. The disk I02 is loosely mounted on the shaft but it is secured, through an adjustable connection, to the disk IIII. The diameter of the disks are equal and such in relation to the position of the disks lever 99 that when the cam follower I00 rides on the edge of the disks, the shaft 9I is positioned to hold the lug 14 out of the notch 89 in the latch Hi. The disk IOI has two radial notches I04 and. I 05 at diametrically opposite points, each of which is wide enough to receive the cam follower I00. The disk I02 likewise has two radial notches I06 and I9! at diametrically opposite points of the same depth as the notches I04 and I 05. The notch I06 is, however, elongated.

An arcuate slot I08 is provided, in the disk IN and at each end of the slot, there is a recess, of a larger diameter than the width of the slot, in theouter surface of the disk, such as the recess I09. The end of a fitting H0 is received in the recesses at the ends of the slot. The fitting is hollow and receives the head of a screw I I I. This screw extends through the fitting, the slot I 08 and into a threaded opening I I2 in the disk I02. A spring I I3 within the fitting abuts against the head of a screwIII and the base of the fitting, acting to drawthe disks together and hold the fitting in a' recess. By withdrawing the fitting against the action of the spring and moving it to the recess at the opposie end of the slot, the

9 position of the disk I921 respect to the disk IOI. I i

As seen in Figs. 13 and 15, the disks are so related that there are two, diametrically aligned notches, into which the cam follower I90 may enter. This is the relative position of the disks for sewing two-hole buttons, that is, wherein the drive shaft makes but eight revolutions and the cam shaft one-half revolution. when the stop motion operates tostop the machine. .By shifting the fitting III) to the recess I99, the disk I02 will be moved counter clockwise (Figs. 13 and and the notch I9I will be closed. Because of the elongated notch I96 in the disk I92, however, the notch I04 will remain. open to receive. the cam follower, and in consequence, when the cam shaft makes one half revolution, the plunger housing will be held suspended and the lug I4 will not drop into the notch I5 in the disk I8. On the next half revolution of the cam shaft, the cam f ollower will drop into the notch I94 and the stop mechanism will operate to stop the machine.

Thread handling mechanism Concomitantly with the operation of the ma chine, in proper sequence and in'timed relation with the stitch-forming and tying operations, the thread is subjected to various tensions and strains and nipped or broken. The mechanism for performing the functions is here termed the thread handling mechanism. At the rear of the column 3 of the machine, a bracket "I I4 is secured for holding a spool of thread which, of course, is free to rotate as; the thread is withdrawn. From the spool the thread is leadthrough certain tension devices and eventually through the eye of the needle. v

On the top of the arm 4 (Figs. 2 and 6) of the frame, there are three posts H5, H6 and Ill extending vertically from the arm along the centerline thereof, and a fourth post IIB, spaced longitudinally of the arm. Forwardly of the post H8, there is a square block I I9 secured on the arm and extending therefrom. Between the posts I I5 and I I5, there isa thread tension device I29, of the usual and well-knownkind, consisting of a pair of tension disks I2I and I22 resiliently urged together by a spring I23. Between the posts [It and Ill and overthe shaft 9, there is another thread tension device I24.

The tension device I24 includes a pin I25 which extends into the arm of the machine in cooperative relation with respect to a cam surface, I25 on the shaft 9. With the movement of the shaft 9, the pin is elevated concomitantly with the stitching operation to release the tension on the thread. The tension is released on each stitching operation to permit the'looper to draw off the necessary thread for twisting andpositioning the loop.

Also mounted on the armf4 of the frame, there is a thread pull oil device. This consists or abell crank lever lzllpivotallymounted on a pivot screw I23. The lever includes a pair. of arms I29 and I39 the ends of which are spaced apart and each of which has an upstandingfinger, the fingers l3I and I32 respectively. At the end of each stitching operation, in a manner hereinafter described, the lever I2! is actuated to cause the fingers I3I and I32 to draw off suiiicient thread for the start of the next stitching cycle.

Cooperating with the block II9 (Fig. 6), there is a fiat extension I33 formed as a part of a bell crank lever I34. The lever I34. is mounted on a pivot pin I secured in the arm 4.. At the end may be changed with or a stitching ycle, as and in the manner here,- 3

inafter described, the bell crank lever I34 is actuated to hip or squeeze the thread between theextension I33 and the adjacent flat surface of the block H9. The lever I34 also carries a horizontal post I35" under which the thread passes in passingto an opening through the upper end of the needle bar.

The frontof the needle bar head (Figs. 1 and 10) is covered by a plate I36. On this plate there is-a leaf-spring thread tension I31 held inplace by a machine screw I38. Through a. slot in the plate a bar I39 extends, and secured in the. bar, there is a rod I49 having an outwardly turned end. Additionalrods I4I and I42 are secured to the plate and each has an arm extending transversely of the plate and spaced therefrom. The rod I49 is between the rods I 4I and I42. These rods serve to place, at the end of a stitch cycle, a preliminary strain on the thread to more readilyeffect a breaking of the thread at the end of the tying stitches.

The foregoing operative parts, those actuated at the end of a stitch cycle, areactuated through the rod I39. The rod I39 extends. along the side of the arm 4 and it is slidably mounted therein. It is normally resiliently urged to its rearmost position by a spring I43. The end of the bar has a transverse extension I44 which is in cooperating position with respect to one end of a bell crank lever I45, pivoted on a-pivot screw- I46. I On the bar I33, intermediate the ends thereof there is a fitting I41 having an extension I48 (Fig. 6) which on forward movement of the bar engages between the disks of the tension device I2I and relieves the tension on the thread. The lever I 21 is actuated by the bar I39 through a stud I49 extending from the lever and engaging in a yoke I49a on the bar. A like stud I59 extending from the lever I34 is positioned to be engaged by a block I5Ila on the bar I39 to actuate the lever I34. The lever I34 is spring urged by a spring I34a to a position in which the surface I33 engages the block II9. When the bar I39 is inthe rearmost position the block I5fla holds the lever against the action of the spring.

At the end of a stitch cycle, the bar I39-is moved forwardly. This action is effected through a lever (Fig. 3) I5I rotatably mounted on the extended end of the shaft 9 and having an arm I52 in cooperative relation with respect to a stud I53 extending from the bar I39. The other arm of thelever I5I is connected through an adjustable pivot screw I54 adjustable in a slot I55 in the arm of the lever I9I, to one end of a link I59. At the other end of the link I56 there are two spaced notches I51 formed in the link, either of which may receive a pin I58 extending from a lever I59 adjacent the end thereof. The lever I53 is rotatably mounted on the driveshaft I4 and has a curved end section I69 that is positioned to be engaged (Fig. 16) by a cam' IBI secured on the cam shaft 48. i

The cam I5I is in eifect a two point cam having two lever-engaging points I and I66 at diametrically opposite points. As the cam I6I is mounted on the cam shaft, the bar I39 is actuated for each half revolution of the cam shaft-twice for each revolution of the cam shaft. Thus, as the drive shaft makes eight revolutions for a cycle of stitches for two holes ina button, the bar I39 is actuated after each such cycle.

The thread (Figs. 1 and 6) indicated by the line IB'I passes from the spool at the rear of the machine, along one side of the post H5, through the tension device I29, across the post I- IS,

through the tension I24, and past the post II1. It will be noted that the thread passes on opposite sides of the successive posts and tension devices. Thus, the posts serve to maintain the thread in the tension devices. From the post I I1 it passes along the post II8, on the same side thereof as the post II1. It is lead from the post H8 between the block H9 and the extension I33 of the lever I34. Next it passes under the horizontal post I35 on the lever I34. From the post I35, the thread passes'KFigs. 1 and through an opening provided therefor adjacent the top of the needlerbar. Then. (Fig. 10) the thread passes down the cover plate of the needle bar, under a rod I62 and the rod I42, over the rod I40 and under the stationary bar MI and under the leafspring I 31. The thread is then passed through a thread hole in the plate and the eye of the needle. Between the rods I62 and I42, the thread passes through the loop of a spring I63 secured to the plate and extending under the rod I40.

During the stitching cycle, the stitches, as heretofore described, are formed the tension device I24 being released in the manner stated during each reciprocation of the needle. At the end of the stitching cycle, the bar I39 is actuated to release the automatic tension I 2I, actuate the lever I21, release the lever I34, and move the bar I40 outwardly which places a preliminary strain on the thread. This is effected through movement of the lever I59.

While the bar I39 is at its rearmost position, the spring I31 is held away from the plate I36 and does not place any tension on the thread. This is effected through a lever I3'Ia (Fig. 3) pivoted on a. lug I31b secured to the plate. One arm of the lever has an extension I310 extending through a slot in the plate and engaging the spring I31. A spring I3'Id acts between the other leg of the lever and the rear of the plate I36 and during stitching operations holds the spring I31 away from the plate in opposition to the adjustable spring I31e tending to press the leaf spring I31 against the plate. When the bar I39 moves forward at the end of a stitch cycle, a pin I31f thereon engages the leverv I31a and releases the leaf spring I31. The leaf spring I31 then clamps the thread to the face of the plate I36.

Upon movement of the bar I39, forwardly, the lever I34 is moved so that the thread is clamped between the block II9 and the extension I33 of the lever I34. The stitch forming mechanism has, at this time, completed a tying stitch. Upon movement of the bar forwardly the U-shaped bracket I40 is, of course, moved forwardly and as the thread is held between the tying stitch and the .clamp extension I33, it is strained. The automatic tension I2I is released so that on the actuation of the lever I-21, a quantity of thread is pulled off, an amount sufficient to start the next stitching operation. This action takes place as the needle starts its return stroke. Further movement of the needle, causes the thread to break at the tying stitch and it is not therefore withdrawn from the needle. 7

At the end of a stitch cycle, the button clamp is lifted. The button clamp, hereinafter described in detail, is, as previously described, secured to the bracket 29 which is pivoted to the lever 32. Secured to the lever 32, there is also a feed plate I68 which extends forwardly of the lever 32. The feed plate has an opening therethrough for the needle, the opening being of a size sufficient to permit the passage of the needle irrespective of the position of the plate. It is also provided with a knurled surface. On this feed plate the cloth is placed and the button clamp is moved down, holding a button, so that the button clamps the cloth to the feed plate. To this end the bracket 29 is urged about its pivotal connection to the lever 32 by a spring pressed plunger I69. The plunger I69 is slidably mounted on a stud I10 extending from the arm 4 abuts against the bracket 29. A spring I1I acts between an adjustable finger nut I12 on the plunger and the arm 4 of the machine.

For raising the bracket 29 and in consequence the button clamp, the bracket 29 is provided with a boss I14 in which one end of a rod having a horizontal arm I15 is secured. Extending below the arm I15 is the arm I16 of a rod I11 that is secured in one end of a lever I18. The lever I18 is pivotally mounted on. the extending end of the shaft 9 and when actuated in one direction serves to elevate the bracket 29.

The lever I18 is actuated through a bar I153 which is pivotally secured, at one end, to the lever and which extends down through the column of the machine to the base. Th lower end of the bar I19 is pivotally secured to one end of a link I (Figs. 4, 17 and 18), the other end of which link is pivotally secured to the end of a bracket or lever IBI secured to the shaft 9I for movement therewith. Adjacent the lower end thereof. the bar is provided with a notch I82 in the edge thereof forming a shoulder I83.

The bar I19 is depressed at the end of a stitch cycle by a cam follower bracket I84. The bracket I84 is pivoted on a shaft I85 and has a U-shaped section embracing an eccentric cam I86 mounted on the shaft I4. Cam engaging surfaces I81 and I88 engage the cam I86 and the bracket is oscillated as the shaft I4 rotates. An arm I89 on the bracket has a lateral extension I90 which under certain conditions engages the shoulder I83 and actuates'the bar I19 to lift the button clamp.

When the plunger housing 84 is raised in starting the machine in the manner previously described, the shaft. 9| is actuated. It is turned clockwise, as seen in Fig. 17. The bracket I 8i, through the link I80 moves the bar I19 such that the extension I90 on the cam follower bracket I84 is out of the notch I 82. It is held in this position, as previously described through the stitch cycle, at the end of which the cam follower I00 drops into a notch in the cycling cam disks I0 I and I02 and the lug 14 on the plunger 13 drops into the notch 15. At this time, the shaft 9| moves counter clockwise (Fig. 17) and on the succeeding oscillation of the bracket I84 the extension I90 engages the shoulder I83 and so effects a lifting of the cam bracket 29.

With the lifting action of the clamp, and through the mechanism just described, there is provided an additional arrangement for eifecting movement of the bar I39. This is effected through the bell crank lever I45 one end of which is in cooperatin relation with respect to the end extension I44 of the bar I39. The other end of the lever extends under a pivot pin I9I securing the .bar I19 to the lever I18. Thus, when the bar I19 is moved downwardly, the bar I39 is moved forwardly through the action of the lever.

The button clamp may be any one of many well known in the art. The particular button clamp illustrated is comparable to that disclosed in United States Patent No. 2,009,560 issued July 30. 1935 with one exception. In the button clamp illustrated, the position of the adjusting pin I92 (Fig. 8) is positioned and held in place by a lever I93. The lever is pivoted at one end on a pivot screw I94 and traversestthe path of the adjusting pin I92. Adjacent its opposite end, there is an arcuate slot I95 through the lever and through which a clamping thumb screw I95 extends. An upturned flange I91 formed adjacent the end of the lever constitutes a finger piece for moving the lever. By loosening the thumb screw and moving the lever, the adjusting pin may be set at any position. This determines the amount the jaws I98 will close. 1

The machine also includes what may be termed a thread wiper for moving and holding the free end of the thread to the rear of the needle so that it does not interfere with inserting a button between the jaws of the button clamp. This thread wiper (Figs. 1 and 3) consists of a stiif wire I99 secured to and extending from one arm of a lever 290. The wire I99 has an end section 29! that extends substantially horizontally and the Wire is of suihcient length so that in the upper position of the needle, the end section 29I can swing under the needle. The lever 299 is pivoted to the frame at 292 and includes an arm 2% upon which a spring 204 acts to move the lever such that the wire is posi tioned to the rear of the needle. Another arm 295 of the'lever is in the form of a yoke, one arm 296 of which is longer than the other. A bracket 291 is secured on the bar I39 and carries a pin 298 which engages in the yoke of the lever 200. I

In the position illustrated in Fig. 3, the inoperative position of the machine, the bar I39 is in its most forward position. The wiper is in its rearward position. When the machine is started, the bar I39 is released and immediately moves to its rearmost position. In doing so, the pin 2B8 moves the lever 20!! to bring the wiper to a position in front of the needle. The arm 206 ofthe yoke on the lever lies, in the inoperative position of the parts, in the path of a block 209 secured on the needle bar 6. It is, however, upon rearward movement of the bar I39, moved out of the path of theblock 299. This is to prevent downward movement of the needle before the wiper has been moved to a position forwardly of the needle.

At the end of a stitching cycle, the machine is stopped and the thread broken as heretofore explained. The bar I99, upon the stoppingof the machine is moved to its forward position. In dOlIlg so the spring I3Id is released and the wiper is moved to its rearmost position. The spring I3'Id. takes up part of the slack in the thread insuring that the free end is Withdrawn and the wiper moves the free end rearwardly of the needle as illustrated in Fig. 3.

Operation In operatin the machine, the operator places a button between the jaws of the button clamp. This is done simply by pressing the edge of the button between the jaws I98 until it engages a stop 2H]. The jaws yield to receive the button and hold it when it is inserted between them. The clamp has, of course, been previously adjusted for the particular size button to be sewn. Also the finger lever 52 has been adjusted for the particular button, that is,'fora two orfour hole button as the case may be, and if for a four hole button for the distance between the two pair of holes. Likewise, the control disks IN and III; have been adjusted for the particular button, i. e., a two or four hole button. In addition, the pivot screw .33 has been adjusted in accordance with the distance between the holes of a pairof holes in the particular button to be I sewn.

multaneously, the lever 64 is elevated and the wedge-shaped end thereof causes the cone clutch to engage, connectin the drive shaft I4 to the pulley 62. Also, the shaft 9| is rotated and the cam follower I09 moved out of the notch in the control disks. When the operator releases the foot treadle, the cam follower I rides on the edge of the control disk and maintains the plunger housing 84 and the lever 64, elevated.

Immediately upon movement of the shaft 9!, the link I19 (Figs. 1'7 and 3) is released. The lever H8 is, thus, released and the button clamp moves down to clamp the fabric between the button and the cloth .plate. The bar I99 is also released and moves to its rearmost position, When this occurs, the automatic tension becomes operative, the lever I21 is moved to release the thread it took off when the machine stopped, the nipper lever I34 is actuated to release the thread, the spring I3Id is retracted, the bar I49 is withdrawn, the tension I37 is released, and the wiper I99 moves to its position forwardly or the needle. The machine operates to effect stitches successively through different holes of a pair of holes in the button and at the end of a stitch cycle to effect tying stitches.

If a four hole button is being sewn, then. after the tying stitches for the first pair of holes, the lever I59 is actuated to move the bar I139 forward. With this action the thread handling mechanism comes into play to break the thread. The lever 32 is moved rearwardly to bring the second pair of holes of the button into position. This is done without interruption of the opera tion of the stitch-forming mechanism.

At the end of a stitch cycle, the cam follower I 99 drops into a notch in thecontrol cams. This releases the shaft 9I so that the stop-motion mechanism becomes effective. Also the link I19 is positioned to be engaged by the extension I99 of the bracket I84. The button clamp is thus raisedand the bar I39 is moved forward. The thread handling mechanism comes into play and the thread is broken. The button is removed from the button clamp and the machine is ready to repeat the operation.

It will be obvious that various changes may be made by those skilled in the art in the embodiment of the invention illustrated in the drawings and described in detail above within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. In a sewing machine having stitch-forming mechanism and operating mechanism therefor, thread handling mechanism comprising in com bination a releasable thread tension device, means for releasing the tension device, thread clamping mean between said tension device and the stitch forming mechanism, means for drawing off thread positioned between said tension device and said thread clamping means, and meansoperative upon the formation of a predetermined number of stitches for actuating said tension device re- '15 leasing means, said thread clampingv means, and said means for drawing on? thread.

2. In a sewing machine having stitch-forming mechanism including a needle and means for reciprocating the needle, thread handling mechanism comprising in combination, a releasable thread tension device, means for releasing the thread tension device, thread-clamping means between the tension device and the needle, means for drawing off thread positioned between the tension device and the thread-clamping means, and common actuating means therefor automatically operable to simultaneously actuate said means for releasing the thread tension device and said clamping means. Y

3. In a sewing machine having stitch-forming mechanism including a needle, and means for reciprocating the needle, thread-handling mechanism comprising in combination a releasable tension device, means for releasing the tension device, thread-clamping means between the tension device and the needle, means for drawing off thread positioned between the tension device and the thread clamping means, thread tensioning means positioned between the thread clamping means and the needle operative to efiect an elongation'of the thread between the clamping means and the needle, and means operative upon the formation of a predetermined number of stitches for effecting the operation of the thread handling mechanism.

i. In a sewing machine having stitch-forming mechanism, operating mechanism therefor and thread control means operative upon the thread passing to the stitch forming mechanism; the

combination for actuating the thread-control means, comprising an oscillating lever, an operating element, and means for effecting a connection between said oscillating lever and said operating element upon the formation of a predetermined number of stitches;

5. In a sewing machine having stitch-forming mechanism and operating mechanism for the stitch-forming mechanism, the combination comprising a needle bar head, a face plate on said needle bar head, a leaf-spring thread tension device on said face plate, positioned to cooperate with the face plate to place tension on a thread therebetween, means for releasing said thread tension, and means actuated by said operating mechanism for rendering said releasing means ineffective.

6. In a sewingmachine having stitch-forming mechanism, the combination comprising a thread tension, means for releasing said tension, a thread-clamp located intermediate the thread tension and the stitch-forming mechanism, thread tensioning means located intermediate the thread clamp and the stitch-forming mechanism, means for operating the machine through a predetermined sewing cycle, means for actuating said first mentioned thread tension and thread clamp and severing the thread a plurality of times during said sewing cycle.

7. In a sewing machine having stitch-forming mechanism, a thread tension, means for reelasing said tension, thread pull-off means located intermediate the thread tension and the stitch-forming mechanism, a thread clamp located intermediate the thread pull-off means and the stitchforming mechanism, thread tensioning means located intermediate the thread clamp and the stitch-forming mechanism, means for operating the machine through a predetermined sewing cycle, and means for actuating said first men- 16 tion'ed thread tension, thread pull-off means and thread clamp a plurality of times during said sewing cycle. l

8. Ina sewing machine having stitch-forming mechanism, a thread tension, means for releasing the thread tension, thread pull-ofi means located intermediate the thread tension and the stitch-forming mechanism, a thread clamp located intermediate the thread pull-off means and the stitch-forming mechanism, thread tensioning means located between the thread clamp and the stitch-forming mechanism, thread-end moving means located intermediate the thread tensioning means and the stitch-forming mechanism, means for operating the machine through a predetermined sewing cycle, and means for actuating said first mentioned thread tension, thread pull-offmeans, thread clamp and threadend moving means a plurality'of times during a sewing cycle.

9. In a sewing machine having stitch-forming mechanism, a thread tension, means for releasing the thread tension, thread pull-01f means located intermediate the thread tension and the stitch-forming mechanism, a thread clamp located intermediate the thread pull-off means, and the stitch-forming mechanism, thread tensioning means located between the thread clamp and the stitch-forming mechanism, thread-end moving means located intermediate the thread tensioning means and the stitch-forming mechanism, means for operating the machine through a predetermined sewing cycle, and means for actuating said first mentioned thread tension, thread pull-ofi means, thread clamp and thread-end moving means a plurality of times during said sewing cycle including a slidably mounted bar, means on the bar fOr eifecting the actuation of said instrumentalities, and means for actuating the bar a plurality of times during said sewing cycle.

10. In a sewing machine having stitch-forming mechanism, a thread tension, means for releasing the thread tension, thread pull-off means located intermediate the thread tension and the stitch-forming mechanism, a thread clamp located intermediate the thread pull-off means and the stitch-forming mechanism, thread tensioning means located between the thread clamp and the stitch-forming mechanism, thread-end moving means located intermediate the thread tensioning means and the stitch-forming mechanism, means for operating the machine through a predetermined sewing cycle, and means for actuating said first mentioned thread tension, thread pull-off means, thread clamp and thread end moving means a plurality of times during said sewing cycle including a slidably mounted bar, means on the bar for effecting the actuation of said istrumentalities, and means for actuating the bar at the end of a sewing cycle.

GEORGE WILLIAM NELSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 773,780 Borton Nov. 1, 1904 1,117,302 Ballard Nov. 17, 1914 1,288,076 Lyons et a1 Dec. 17, 1918 1,671,124 Plumley May 29, 1928 1,999,145 Vollman Apr. 23, 1935 2,009,560 Morris July 30, 1935 2,186,762 McCann Jan. 9, 1940 2,294,471 Lyon Sept. 1, 1942