US679914A - Sewing-machine. - Google Patents

Description

No. 679,9I4. Patented Aug. 6, 190|. H. P. RICHARDS. SEWING MACHINE.

(Application led Sept. 12, 189B.\ 4 (No Model.) 4 sheets-'sheer no. 679,9l4.

Patented Aug. 6, |90I.

lH. P. nlcHAnns. SEWING MACHINE.

(Application lvd Sept. 12, 1898.)

(No Model.) Sheets-Sheet 2.

ma' fm Tu: aonms Urns ou., moro-uma.. wAsNxNnroN. u t:4

No. 679,9I4. Patented Aug. 6, |90I.

H. P. RICHARDS.

1 SEWING MACHINE.

(Application med sept. 12, 189s.)

4 Sheets-Sheet 3.

(No Model.)

fitness e @M s l Inventor No. 679,9l4. Patented Aug. 6, |901. H. P. RICHARDS.

SEWING MACHINE.

(Application Bled Sept. 12, 1898.)

4 Shee1s-`sheet 4. Y

(No Model.)

Invent-f Witnesses TH: ohms Pmns cu., PHnToLlrHa. wAsHmGToN. nv c.

i UNITED. STATES PATENT CEEICE. f

HUBERT P. RICHARDS, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO J.

EVARTS TRACY, OF PLAINFIELD, NEW JERSEY.

SEWING-MACHINE.

SPECIFICATION forming part of Letters" 15a/cent No. 679,914, dated August 6, 1901. Application tied september 12,1a9e`. sentira. 690,730. (Nomnaem To @ZZ whom, it may concern:

Connecticut, have invented certain new and useful Improvements in Sewing-Machines, of which the following is a specification.

This invention relates in a general way to sewing-machines of that class in which the stitch-making mechanism includes a reciprocatory needle, a rot-ary looper adapted for carrying successive loops, and means for reciprocating the needle and rotating the looper and whereby the loop of the needle-thread may be formed and be engaged by and carried entirely around the looper to inclose a lower thread to form a lock-stitch or may be carried through a preceding loop to forni a chain-stitch or a chain lock-stitch; and the invention more particularly relates to a socalledfcombined lock-stitch and chainstitch mechanism embodying instru menta-lities normally operative for forming a lockstitch and also embodying a stitch-changing device shiftable into position to engage successive loops and to so act thereon as to elect a change in the form of stitch made.

An object of the invention is to provide a differential stitch-making mechanism including an adjustable tension device and automatically-operable adjusting means for varyt ing the resistance or effective tension ot' the tension device on the needle-thread in accordance with the requirements as determined by the varying conditions present in the making of different stitches and at dierent points in the operation of forming any particular stitch.

A further object of the invention is to provide in a stitch-making mechanism embodying a rotary looper adapted for carrying two loops simultaneously a stitch-changing device operative independent of the looper for engaging one loop and for holding the same in such position that the next succeeding loop will during'the rotation of the looper pass therethrough, a tension device for controlling the tension of theneedle-thread, and means operativo 4with the stitch-changing device for decreasing the stress of the tension device upon the needle-thread when the stitch-chan ging device is shifted into operative relation with the looper and for increasing the stress Be it known that I, HUBERT?. RICHARDS,A4 a citizen of the United States, residing in New. Britain, in the county of Hartfordand State of,

`when the stitch-changing device is thrown out of operative relation with the looper, as re- :quired when the stitch-making mechanism is forming chain-stitches and lock-stitches, re-

spectively.

A further object of the invention is to provide in a stitch-making mechanism embodying a rotary looper adapted for carrying a plurality of loops simultaneously a stitchchanging device independent of the looper` for successively engaging succeeding loops and `for holding said loops in such position that every succeeding loop will pass through a preceding loop, a tension device for controlling *the tension of the needle-thread, and two independently-operating means, one o f which is automatically operated by a cam on the looper-driver shaft and is effective for positively varying the tension at predetermined points in the rotation of the looper and the other of which is automatically operative with the stitch-changing device and is effective for changing the degree of tension on the needlethread, according as a chain-stitch or a lockstitch is being made.

In the drawings accompanying and forming part of this specification, Figure l is a vertical longitudinal section of a sewing-machine embodying my present improvements, parts being broken away. Fig. 2 is a horizontal section taken on a line corresponding to the dot-ted line a a, Fig. l, showing the parts below said line. Fig. 3 is an end view of the machine as seen from the left in Fig. 1. Fig. 4 is a vertical cross-sectional view taken on a line corresponding to the line b b, Fig. l, looking toward the left in said gure. Fig. 5 is a cross-sectional view similar to Fig. 4,

taken on a line corresponding to the dotted line c c, Fig. 1, looking to'ward the left in said figure. Figs. G, 7, 8, and 9 are perspective views of the looper, needle, a portion of the Work-plate, and a piece of fabric, illustrating, respectively, four successivepositions of the parts during the formation ofalock-stitch and indicating the positions of the loops when the fabric is swung about the needle to form a stitch at an angle to the preceding stitch. Fig. lO is an enlarged cross-sectional view of the tension device for the needle-thread and apor- IOC tion of its actuating instrumentalities,the said section being taken on a line corresponding to the dotted line b b, Fig. 1. Fig. 1l isa crosssectional view of the parts shown in Fig. 10, taken on a line corresponding to the dotted line e e in said figure and showing the parts above said line. Fig. 12 is a side view of a portion of the feed-adjusting device detached. Fig. 13 is a perspective view of the pivot-plug of said feed-adj usting device detached. Fig. 14 is a diagrammatic view illustrating the relative movements of the needle and looper and their actuating devices.

Similar characters designate like parts in y all the figures of the drawings.

In the drawings only so much of a sewingmachine is shown as is deemed necessary to illustrate the application and mode of operation of my present improvements. y

My improved sewing-machine will usually comprise a framework, (designated by A,) which may be of any suitable general coustruction, for carrying the working parts of the machine; a vertically-reciprocatory needle-bar N, carrying the needle N; a horizontal needle-bar-actuating shaft D, (shown asa crankshaft,) journaled in suitable bearings in the framework and operatively connected with the needle-bar by a crank and link in the usual manner; a rotary looper S, disposed at an inclination to the path of movement of and below the needle-bar and having 'a plurality of loop-takers or hooks; a'looper-guide G, supported by a bracket G' on the frame and extending partially around the looper; a looper-supporting driver H; a horizontal looper-actuating shaft D', supported 'in suitable bearings below the bed-plate of the machine; a main driving-shaft D2, horizontally disposed in parallelism with and at one side the axis of the looper-actuating shaft and having a crank operatively7 connected with the crank of the needle-bar shaft by a link or pitman D in the usual manner; a two-to'- three train of gears E between and operatively connevcting the main driving-shaft and looper-actuating shaft; feed mechanism operated from the main driving-shaft; a presserbar P, having a presser-foot 7 cooperating with the feed-plate of the feed mechanism for holding the fabric; a rock-shaft D3, journaled in the framework at one side of the needlebar-actuating shaft D and operatively connected with the presser-bar by a crank in a wellknown manner and having means whereby said shaft may be rocked to raise or lower the presser-bar; a stitch-changing device (designated in a general way by W) shiftable into and'out of operative relation with the looper and effective when'in operative relation with the looper for engaging a loop and holding the same in such position as to permit the next succeeding loop to pass therethrough; means operated by the main driving-shaft for actuating the stitch-changing device; a tension device (designated in a general way by T) for controlling the needlethread, and two independent tension-modifying devices, (designated by T and T2, respectively,) the former of which is controlled by a cam on the inainrdriving-shaft and is effective for varying the tension at predetermined points in the rotation of said shaft and the latter of which is in operative connection with thestitch-changing device and is effective for operating the tension device to change the tension of the needle-thread when the stitchchanging device is shifted into or out of'operative relation withthe looper.

The framework of the machine, which may be of substantially the same general construction as the framework of the machine del scribed in Letters Patent of the United States No. 574,573, granted to Francis H. Richards January 5, 1897, to which reference may be had, usually comprises a horizontal bed-plate 2, having a depending looper-guide-supporting bracket G' at the work-supporting end thereof, a hollow upright 4 at the opposite end of the bed-plate, a horizont-al arm 5 above said bed-plate, and arvertical needle-bar-receivin g head 6 at the free end of the arm 5.

The nee'dle-bar N and presser-bar P are shown, as in the patent referred to, axially coincident, the needle-bar being supported for reciprocatory movement in the presserbar, which is in turn supported for vertical movement in the head 6, and is furnished at the lower end thereof with the presser-foot 7, a resistance-spring (not shown) being in practice provided, as in said patent, for regulating the pressure of the presser-foot upon the fabric.

The rotary looper S maybe similar in a general way to the discoidal loop-taker described in the patent referred to and is supported below the bed of the machine for rotative movernent in a plane oblique to the path of the needle, (see Fig. 1,) said looper being guided in its rotation and held against movement transversely of its path of rotation by the parti-circular looper-guide G, which extends around the lower portion and has a raceway for receiving the perimeter of said looper, such raceway being in practice of sufficient depth to permit a slight diametrical movementof said looper. Said looper will in practice be furnished with some suitable meanssuch, for instance, as that described in the v patent referred to, but not shown in the accompanying drawings-for carrying a lower thread, cop, or bobbin and will also be provided with some suitable tension device for the lower thread. In the form shown the looper is furnished with a set of three correspondingly-disposed loop-taking hooks, which are designated by 7L, h', and h2, respectively, and also has formed in the inner face thereof a series of driver-sockets 8, disposed preferably concentric to the axis of the looper and equidistant to one another, which sockets are adapted for receiving corresponding driving-pins 9 upon driving-arms 10 of the driver H, which driver may be of the same general IOC- IIO

w www shaft-the looper having three equidistant` hooks-is connected to the main driving-shaft by a two-to-three train of gearing E in such a manner as to have two complete rotations to every three completerotations of the main drivingshaft, and consequently has twothirds of a complete rotation at every complete reciprocation of the needle-bar, the ratio of movement between the looper and needle being the saine in the present instance as in the patent referred to. The two-to-three train of gears E is shown comprising an internal gear-wheel 12, ixedto the end of the shaft D', and a pinion 13, fixed to the end of the driving-shaft D2 and meshing with said internal gear.

The feed mechanism shown comprises two substantially parallel rock-shafts R and R', located at opposite sides, respectively, of the looper-actuating shaft D' and journaled in bearings below the bed-plate 2 of the machine; two cranks 14 and 15, fixed to the outerends of the rock-shafts R and R', respectively; a feed member K pivotally secured at one end to the outer end of the crank 14 and having the opposite end thereof bifurcated and in shiftable connection with a stud 15', fixed to the outer end of the crank 15; two cranks 16 and 16', secured to the inner ends of the rockshafts R and R, respectively; a compound feed-member-advancing linkage operatively connecting the crank 16 and eccentric 18, and

' a feed-member-elevating linkage operatively connecting the crank 16' and said eccentric, said feed member advancing linkage and feed-member-elevating linkage being so constructed Yand disposed and so timed in their movements oneV relatively to thc other that during one complete cycle of movements of the driving-shaft D2 and eccentric 18 from a normal ineffective position the elevatinglinkage will be first shifted to impart a feedmember-elevating movement `to the rockshaft R' and its crank, after which the feedmember-advancinglinkage will impart a feedmember-advancing movement to the rockshaft R and its crank and after which the elevating-linkage will operate to depress the feed member, and the feed-member-advancing linkage will then operate to impart a retractive movement to said feed member or feed-plate, the operations of the two linkages taking place in alternation. The feed-member-advancing linkage in the form thereof shown in the accompanying drawings comprises a short vertically-disposed link 19, pivoted at its lower end to a projection on the strap 2O of the eccentric 18, and a horizon- 'tally-disposed link 2l', pivoted at its inner end to the upper end of the link 19 and pivotally connected at its outer end to the free end of` the crank 16. The feed-member-elevating linkage is shown comprising a crank-shaft R3, disposed intermediate the rock-shaft R' and main driving-shaft D2 and having two differently-disposed cranks 24 and 24',respcctively,

a horizontallydisposed link 25, preferably formed integral with and constituting a part of the eccentric-strap 2O and pivotally connected at its outer end to one of the cranks, as 24, of the crank-shaft R3, and a verticallydisposed link 26, pivotally connected at its lower end to the crank 2li' of said crank-shaft R3 and pivotally connected at its upper end to the crank 16 of the rock-shaft R. Thel dispositions of the cranks and eccentrics of the feed-member-elevating linkage will be such as to secure a comparatively short stroke of the feed-member-elevating crank 15 at each semirotation of the drivingshaft D2.

As a means for changing the working stroke of the feed-plate K and simultaneously chan ging the working position of said feed-plate I have provided a feed-adjusting device, (designated in a general way by M,) which in the preferred form thereof comprises a slidebar 27, supported for horizontal movement in a way 27', formedin a portion of the framework below the bed-plate of the machine,

and which slide-bar has at the inner end thereof a depending portion 28, which is piv- Votally and adjustably connected to the link 2l intermediate the ends thereof and constitutes the fulcrum on which said link swings and also governs the range of movement of said link.

For the purpose of forming a sliding pivotal connection between the adjusting device M and link 2l the depending portion 28 of said device has a transverse socket- 29 formed in one face thereof, in which is seated a bifurcated plug or pivot 30, the bifurcated end of which plug straddles the link 21, said plug being supported for oscillatory movement in the depending portion 28 of said device M, as will be understood readily by reference to Figs. l2 and 13 of the drawings.

As a convenient means for shifting the adjusting device'M to change the fulcrum of the link 2l, and consequently the working stroke of the feed-plate K, I have provided a shifting device, which may be a screw extending through a guideway in the bed-plate of the machine (see Fig. 5) and into the slidebar 27 of the adjusting device M and having at its upper end a knurled head, whereby the same may be turned to hold the adjusting device in its adj usted position.

Inasmuch as the general operation of the looper and Afeed mechanisms in the present machine in forming a lock-stitch is somewhat similar to that of the same parts in themachine described in the patent referred to, a detailed description of this operation 'is deemed unnecessary, it being suflicient to IOO IIO

tation thereof to inclose the lower thread and form a lock-stitch, each preceding loop being drawn up by a succeeding loop as said succeeding loop is partially drawn out by the looper during the rotation thereof, as will be understood by reference to Figs. 6 to 9, inclusive, of the drawings. In the organization of mechanism shownin the accompanying drawings the looper S will be constantly rotated in one direction during the operation of sewing, preferably in the direction of the arrows in Figs. 3, 4, 5,and 6 to 9 of the drawings, and toward the front side of the machine.

As a convenient and simple means for changing the form of stitch resulting from the normal operation of the needle and looper mechanisms hereinbefore described without effecting a change in the direction of movement of the looper or feed device or in the .mode of operation of the several lock-stitch mechanismsto wit, the looper mechanism, the needle mechanism, and the feed mechanism-I have provided a stitch-changing device (designated in a general way by W) which is in all essential characteristics substantially the same as the stitch-changing device described in my Patent No. 607,079, dated July l2, 1898, said stitch-changing device being shiftable into position for coperating with the looper and being effective for engaging the upper portions of successive loops and for deflecting said portions laterally of the path of the needle, so that succeeding loops may pass through` preceding loops and cause the stitch-forming mechanism to produce a chain-stitch or a chain lockstitch. The construction andorganzation of the stitch-changing device are such that the same may be thrown into or out of oper- `ative relation with the looper to change the form of stitch made by the stitch mechanism without the necessity of changing the direction of rotation of the looper or the direction of movement of theV feed mechanism and without the removal or substitution of parts, as heretofore necessary in machines of ordinary construction, and hence said device forms with the looper mechanism a changestitch mechanism adapted for making different kinds of stitches as desired.

The stitch-changing device W, as shown most clearly in Figs. 2 and 4t of the drawings, comprises a loop-diverter 60, (shown as a lever,) fulcrumed at 60 below the bed-plate of the machine for horizontal oscillation across the path of the loops, actuating means for the loop-diverter, which is herein shown as a lever 62, fulcrumed at 62' at one side the axis of the main driving-shaft D2, an actuatingrod 63, pivotally connected at one end to the actuating-lever 62 and at its opposite end to one end of the loop-d iverterpO, and a cam 64, xed to the driving-shaft D2, which has two oppositely-disposed working faces against which a roll 64 on the inner end of the actuating-lever 62 bears, said cam being adapted for advancing and retract-ing the loop-diverter 60 across the path of the loops, as will be understood by reference to Fig. 2 of the drawings.

As a means for throwing the stitch-changing device out of and into operative relation with the looper I have provided a throw-out device W', which is shown asa stud 62", supported for rotative and longitudinal movement in a vertical bearing formed in the framework, which stud has its lower end eX- teuding through the actuating-lever 62 and constitutes the supportvand fulcrum for said lever, and I have provided in connection with said stud a horizontally-disposed actuator 65, (shown as a headed pin,) extending through an inclined or cam groove 66, formed in the upright 4, and having a head at the outer end thereof whereby the stud 62" may be rotated and simultaneously lowered to throw the outer end of the actuating-lever into operative engagement with the working surfaces of the actuating-cam 64E. This stud is provided with a depending lever-actuating projection 67, so disposed Y (see Figs. 2 and 4) that when the stud 62l is raised and rotated Vit will strike the lever at a point intermediate its fulcrum and the `outer end andthrow the same toward the left, as seen in Fig. 2, thereby shifting the working end of the loop-diverter from its working position out of operaative relation with the looper, the cam-groove 66 being upwardly inclined, as shown most clearly in Fig. 3so that when the actuator 65 IOO is shifted toward the left the stud 62, which carries the actuating-lever, will be raised and simultaneously rotated.

It will be obvious that other instrumentalities than those illustrated in the drawings may be employed for actuating the loop-diverter. Therefore it will be understood that I do not limit this invention to the particular means shown.

The actuating-cam 64 is shown constructed to impart both advancing and retracting movements to the loop-diverter; but it will be obvious that it might be constructed to impart a movement to said loop-diverter only in one direction and other means-be employed for imparting a movement thereto in the other direction.

In a sewing-machine of this class it is extremely desirable that means be provided for varying the tension of the needle-thread at dierent points in the rotation of the looper, the preferred construction being one in which the tension of the thread may be decreased just before the engagement of a loop by a loop-taker, so as to prevent breaking of the thread during the rst stagegof the drawing out of the loop, the tension being afterward increased just before the final drawing up of IIO in, LA Ani U the preceding loop.V It is also important in sewing-machines having change-stitch mechanism for making different stitches that the tension should be changed in accordance with the requirements as determined by the kind of stitch being made, it being necessary, for example, to put a greater tension upon a thread for the formation of a lock-stitch than for the making of a-chain-stitch. In the present case one of the main features of the invention is the provision of tension-modif yin g means automatically operative for increasing or decreasing the tension on the thread during the making of each separate stitch, and I also employ meansfor changing the tension by a definite amount when the mechanism is set for the making of another kind of stitch from that for which it may have been set previously. Hereinafter the tension-modifying means automatically operative during the making of any stitch will be termed a tension-varying device and will control the tension device coperating directly with the thread, while the tension-modifying means, which determines the extreme degrees oftension for different stitches, will be termed a tension-changing device and in the preferred form of the invention will be controlled directly by the throwing of the stitch-changing device into and out of operation, it. being obvious,of course, that when the stitch-changing deviceis inoperative and the mechanism operates to make a lock-stitch the tension should be quite high, while when the stitchchanging device is thrown into position to cooperate with the looper and deflect the loops carried therearound the tension should be modified materially, so that it will be much less than is necessary for the making of a lock-stitch.

For the sake of simplicity of construction a single thread-tensioning device-such, for example, as that indicated herein by T-will be used ordinarily, and this may be controlled by both the` tension-varying device and the tension-changing device conjointly, these two tension-modifying devices being designated, respectively, by T and T2, as before stated.

The tension device shown in the drawings embodies two tension-plates, such as 35 and 36, one of which, as 35, may be supported on a suitable projecting portion or boss 37 of the framework, the other being loosely carried in this instance by a sleeve 38, supported for reciprocation in alongitudinal bore in the boss 37, an adjustable stop or stop-nut, such as 39, being secured to the upper screw-threaded end of the sleeve 3S, between which stop and the tension-plate '36 a coiled spring 40, encircling said sleeve, may work. In the construction shown the part which operates directly to vary the tension of this spring during each stitch-making operation is a rod 41, supported for reciprocation in the sleeve 38 and having a notched opening or recess at one side thereof, one Wall of which forms an actuating member adapted to engage a pin,

such as 42, carried by the tension-plate 346 and extending througha slot iu the sleeve 38. It will be apparent that when the rod 41 is lifted the pin ,42, and thereby the upper tensionplate 36, will also beraised slightly to decrease the tension on the thread between they plates. In the construction illustrated an actuating-rod 43 coperates at its upper end with the lower end of the rod 41 to lift the latter, a coiled retracting-spring being disposed. between the lower headed end 41 of the rod 41 and some portion of the framework. At the lower end thereof the rod 43 may carry a roll 44, which may rest upon a circumferential cam-face 45 at one side of the cam 64 for the stitch-changing device, the spring at the upper end of the rod 43 serving to maintain the roll iu contact with such camface 4 5.

The tension-changing device which I prefer to use embodies a short lever, such as 4G, Fig. l0, having a ball-bearing support 47 between its ends, this lever being mounted in a suitable opening in the framework. At its inner end the lever 46 engages the sleeve3S near the lower end of the latter, and at its outer end said lever is in position to be operated by a thrust-rod to lower the sleeve and the stop-nut 39 to increase the tension when the mechanism is set for the making of a lockstitch, this tension being decreased, ofcourse, as soon as the rod 49 is lowered. At its lower end said rod 49 is connected with the stud or knob which controls the position of the stitchchanging device W and is operated thereby.

From theabove description it will be seen that the tension on the needle-thread will be varied automatically by the operation of the rod 43 during the making of each stitch, whatever Athe character of the latter, and that the tension will be increased or decreased by a certain definite amount by the action of the rod 49, according as the mechanism is set for the making of a lock-stitch or a chain-stitch.

No claim is herein made to the feed mechanism shown and described, for it constitutes the subject-matter of my concurrently-pending application filed April 12, 1900, Serial No. 12,516.

Having described my invention, I claim- 1. In a sewing-machine, the combination, with stitch-forming mechanism, of a threadtensioning device, a stitch-changing device, and automatically-operative tension-varying means controlling said thread-tensioning device and coperating with the stitch-changing device.

2. In a sewing-machine, the combination, with stitch-forming mechanism-of a threadtensioning device; a stitch-changing device; and means controlled by the stitch-changing device for actuating the thread-tensioning device to decrease the tension upon the thread when the stitch-changing device is thrown into operative position and to increase said tension when the stitch-changing device is thrown to its inoperative position.

3. In a sewing-machine, the combination, with stitch-forming mechanism embodying a rotary looper, of a thread-tensioning device; a stitch-changing device Working on the loops of the thread; and a tension-changing device operatively connected with said stitch-changing device.

4. .In a sewing-machine, the combination, with stitch-forming mechanism including a rotary looper, of a thread-tensioning device; automatically-operative tensionmodifying means controlling said threadtensioningde vice and operative for actuating the latter during each rotation ot the looper to vary the tension on the thread; a stitch-changing device; and a tension -changing device controlled by said stitch-changing device.

5. In a sewing-machine, the combination, with stitch-forming mechanism normally operative for making a stitch of one kind, ot' feed mechanism; a stitch-changing device independent of said feed mechanism and controlling the making of a stitch of another kind; a thread-tensioning device; and atension-changing device controlling said threadtensioning device and controlled by said stitch-changing device.

6. In a sewing-machine, the combination, with stitch-forming mechanism normally operative for making a stitch of one kind, of feed mechanism; a stitch-changing device independent of said feed mechanism and controlling the making of a stitch of another kind and shiftable into and out of operation; a thread-tensioning device; and a tension- 'changing device controlling said thread-tensioning device and controlled by said stitchchanging device.

7. In'a sewing-machine, the combination, with stitch-forming mechanism normally operative for making a stitch of one kind and embodying a rotary looper, of feed mechanism; a stitch-changing device independent of said feed mechanism and controlling the making of a stitch of another kind and shiitable into and out of operative relation Withthe looper; a thread tensioning device; and a tension changing device controlling said thread-tensioning device and controlled by said stitch-changing device.

S. I-n a sewing-machine, the combination, with lock-stitch-forming mechanism, of a chain-stitch-forming device shiftable into and out of operation; a thread-tensioning device; and a tension-changing device controlling said thread-tensioning device and controlled by said chain-stitch-forming device.

9. In a sewing-machine, the combination, With stitch-forming mechanism normally operative for making a stitch of one kind. and embodying a rotary looper having a plurality of loop-taking hooks, of a stitch-changing device controlling the making of a stitch of another kind and automatically shiftable into engagement with successive loops a plurality of times during each rotation of the looper; a thread-tensioning device; and a tensiona tension-changing device; a separately-operative tension -varying device controlling the thread-tensioning device conjointly with said tension-changing device; and means for automatically operating said tension-varying device during the making of each stitch.

12. In a sewing-machine, the combination, With stitch-forming mechanism normally operative for making a stitch of one kind, of a stitch-changing device controlling the making of a stitch of another kind; a thread-tensioning device; a tension-changing device controlling said thread-tensioning device and controlled by said stitch-changing device; a separately-operative tension-varying device controlling the thread-tensioning device conjointly with said tension-changing device; and means for automatically operating said tension-varying device during the making of each stitch.

13.- In a sewing-machine, the combination, lwith stitch-forming mechanism embodying reciprocatory needle mechanism and a rotary looper, of a tension device for the needlethread; a shiftable stitch-changing device; and tension-changing means controlling said tension device and thrown into action when the stitch-changing device is shifted.

14. In a sewing-machine, the combination, with stitch-forming mechanism embodying reciprocatory needle actuating mechanism and rotary looper-actuating mechanism, of a tension device for the needle-thread, a stitchchanging device; and automatically-operative tension modifying means controlling said tension device, controlled by a part of the looper-actuating mechanism and coperating With the stitch-changing device.

15. In a sewing-machine, the combination, with stitch-forming mechanism embodying needle-actuatingmechanism and looper-actuating mechanism and normally operative for making a stitch of one kind, of a stitch-chan ging device controlling the'making of a stitch of another kind; a tension device for the needle-thread; a tension-changing device controlling said tension device and controlled by said stitch-changing device; and a separatelyoperative tension-varying device controlling said tension device conjointly with said tension-changing device and operative by a part of the looper-actuating mechanism during the making of each stitch.

IOO

IIO

16. In a sewing-machine, the combination, with stitch-forming mechanism embodying a needle and a looper and normally operative for making a stitch of one kind, of a stitchchanging device controlling the making of a stitch of another kind and operative for deiiecting each loop and holding it in such deflected position until a succeeding loop has passed therethrough; a thread-tensioning device; and a tension-changing device controlling said thread-tensioning device and controlled by said stitch-changing device.

17. In a sewing-machine, the combination, with stitch-forming mechanism, of a tension device embodying a pair of tension-plates and a spring; a tension-changing device controlling said spring; a separately-operative tension-varying device controlling said spring conjointly with said tension-changing device; and means for operating said tension-vanying device automatically during the making of each stitch.

18. In a sewing-machine, the combination, with needle mechanism and a looper, of

change-stitch mechanism, feed mechanism; a tension device embodying a pair of tensionplatesand a spring, and a tension-changing device independent of said feed mechanism `controlling said tension device and controlled HUBERT I). RICHARDS.

NVitnesses:

S. W. PoT'rs, HENRY BIssELL.

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