US1467284A - Thread-measuring mechanism for sewing machines - Google Patents

Description

Sept. 4, 1923. 1.467.284 E. E. FOSTER THREAD MEASURING MECHANISM FOR SEWING MACHINES Filed May 28 1917 3 Sheets-Sheet 1 1 w iiygw/or M MM un pikma,

Sept. 4, 1923.

E. E. FOS TER THREAD MEASURING MECHANISM FOR SEWING MACHINES Filed May 28 1917 3 Sheets-Sheet 2 Mum/0r Mk KW Sept. 4, 1923. 1,467.284 E; E. FOSTER THREQ MEASURIRG MECHANISM FOR SEWING MACHINES Filed hiay 28 1917 3 Sheets-Sheet 3 mvemor" WSW Patented Sept. 4, 1923.

UNITED STATES PATENT OFFICE.

EDWARD E. FOSTER, OF BEVERLY, MASSACHUSETTS, ASSIGNOR TO 0. C. BLAKE, IN- CORPORATED, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

THREAD-MEASURING MECHANISM FOR SEWING MACHINES.

Application filed May 28, 1917. Serial No. 171,848.

To all whom it may concern:

Be it known that I, Eownnn E. Fos'rna, a citizen of the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certain Improvements in Thread-Measuring Mechanisms for Sewing Machines, of which the following description, in connection with the accompanying drawings, is a'specification, like reference characters on the drawings indicating like parts 'in the several figures.

This invention relates to sewing machines and is particularly concerned with thread measurin mechanisms for sewin machines. achines of this class usually are equipped with some form of mechanism for measurin off or drawing from the thread supply t e length of thread required for each stitch, thus limitin definitely the amount of thread subjecte to the.manipulation of the sewing instrumentalities in each cycle and thereby enabling the machine to pull up the stitches more uniformly than otherwise would be possible. mechanisms are arranged to vary automatically the length of thread supplied to the sewing instrumentalities in accordance with variations in the thickness of the work. Provision usually is made also in these machines for adjusting the length of stitch; audit is obvious that in order to secure uniformity in the formation of the stitches, provision should be made not only for varymg the amount of thread supplied to the sewing instrumentalities in accordance with the thickness of the work, but also in accordance with changes in the length of stitch. While mechanisms designed to accomplish this object have been -proposed heretofore they have not, so far as I am aware, proved successful; and the usual arrangement has been to design the threadmeasurin mechanism for approximately an average cngth of stitch or to set it'by a hand adjustment and to depend upon some form of automatic thread measuring mecha. nism to vary the thread measurements in accordance with changes in the thickness of the work. Accordingly, if the length of stitch is changed ,without making bv hand. the required adjustment in the thread measuring mechanism. the result will be either to form a tighter or looser stitch than that formerly made or to bring the locking or Usually these intersection of the threads, if the machine is of the lock stitch type, at a different point in the work.

It obviously is desirable both to have the lock or intersection of the threads at substantially the same relative depth in the Work at all points in the seam and also to have the stitches pulled up to a uniform tension so that the strain on the seam shall be uniformly distributed on the stitches; and it is the general object of'this invention to devise an automatic thread-measuring mechanism for sew ng machines which W1 1 accomplish this resu t. The invention also aims to devise a reliable and simple form of mechanism of this character which can be advantageousl used to control the quantityof thread de ivered in response to changes in either the thickness of the work or the length of stitch in cases where it is necessar to provide for variations in only one of t ese conditions.

To the accomplishment of these and other objects of the invention which will hereinafter appear, the invention provides certain novel combinations and arrangements of partsand details of construction, the nature of which will be readily understood from the following description of the embodiment of the invention now preferred by me,

' Referring now to the accompanying drawwas:

Figure 1 is a side elevation of the more important parts of an outsole stitching machine equipped with a thread measuring mechanism embodyin this invention;

Fig. 2 is an elevation showin the opposite side of arts of the threa measuring mechanism s own in Fig. 1;

Fig. 3 is a vertical cross sectional view on the line 3-3, Fig. 2;

Fig. 4 is a plan view, partly in horizontal cross section, showing a detail of construction of the mechanism shown in Fig. 2;

Fig. 5 is a cross sectional view, taken substantially on the line 5--5. Fig. 6. showing the mechanism for adjusting the length of stitch in the machine shown in Fig.1; and

Fig. 6 is a vertical cross sectional view on the line 6-6, Fig. 5.

The sewin or stitching machine shown in the drawings forms the subject matter of the patent to Blake, 1,443,724, January 30, 1922. A detailed description of this machine is unnecessary for the purpose of disclosing the present invention but it may facilitate an understanding of the construction shown to state that the sewing instrumentalities include a needle 2, mounted to reciprocate toward and from a work support or.

throat plate 4, and a looper 6 which presents a loop of needle thread to the needle in position to be caught by the hook of the needle and drawn up through the work. A loop thrower 7 passes this loop of thread over a stationary shuttle located above the work and a cam-operated take up lever 8 then acts on the needle thread to set the stitch. The work is clamped during the stitch-forming operation by means of a resser foot 10 mounted on the lower end 0 a rod 11 which slides through the frame and is acted upon by a spring 12 to hold the presser foot 10 firmly in contact with the work. A camoperated locking mechanism is provided to lock the presser foot in its depressed or work-clamping position while the stitch is being made. The position of the presser foot 10 thus is controlled by the thickness of the work and it is locked in said position while the stitch-forming instrumentalities act on the work. The various sewing instrumentalities are operated by cams fast on a main cam shaft 14 which is driven by spiral gears enclosed in the housin 15, one of these gears being fast on the sha t 14 and the other fast on the vertical driving shaft 16.

The shoe S (Fig. 1) is mounted on a work support, indicated in general by the numeral 18, which operates between successive stitchforming operations to feed the shoe step by step past the stitch-forming instrumentalities. The work supporting and feeding mechanism shown is of the character disclosed in the patent to Blake, 1,430,210, September 26, 1922. But, in the machine shown in the present application the horizontal shaft 19, which operates said mechanism, is driven by an adjustable mechanlsm by means of which the length of each feeding movement, and conse uently the length of each stitch formed, can adjusted.

This driving mechanism is enclosed in housings 20 and 21 and is best shown in Figs. 5 and 6. Referring to these figures, it will be seen that the upright shaft 16 has fast thereon a cam 22 having a cam path formed therein with driving portions and holding portions. A pin wheel 24 mounted fast on a shaft 25 is provided with a series of radial pins or rolls which enter successively the path in the cam 22, so that the constant rotary motion of the shaft 16 is, by this mechanism, transformed into an intermittent rotative movement of the shaft 25. This'me chanical movement is fully disclosed in the patent to Blake, 1,241,911. October 2, 1917. Four pinions indicated respectively at 26,

27, 28 and 29 (Fig. 5) are mounted fast on the shaft 25 and run constantly in mesh with gears indicated respectively at 30, 31, 32 and 33, all loosely mounted on the 1101- low shaft 34. This shaft is connected to the shaft 19.

The respective pairs of pinions and gears are made of different gear ratios and each gear is equipped with a clutch so that, while all the gears normally rotate freely on the hollow shaft 34, any one of the gears may be made effective to drive this shaft. These clutches are all alike and consequently a description of one only is necessary. As best shown in F ig. 6, each clutch includes a hub member 36 keyed to the shaft 34 and mounted within a recess formed in its respective gear. Two friction shoes indicated respectively, at 37 and 38 (Fig. 6) are pivotally mounted in the hub 36 close to its periphcry and they are provided with hook-shaped spring arms which enter slots formed in opposite sides of the shaft 34 and terminate in small knobs 40 that lie just within the bore of the shaft. By referring to Fig. 6 it will be seen that normally the gear 31 can rotate freely on the clutch hub 36- without efi'ecting a rotative movement of the clutch, but if the ends 40 of the spring arms are forced outwardly they will apply sufficient pressure to the friction shoes 37 and 38 to cause them to grip the peripheral wall of the recess in the gear 31 and establish a driving engagement between this gear and the clutch hub 36, thus transmitting the rotative movement of the gear to the hollow shaft 34.

In order to render any one of the four gears shown effective to drive the shaft 34. a clutch actuator is provided which consists of a plunger 41 carrying a head 42 which slides in the bore of the shaft 34. A grooved roll 44 is secured fast to the outer'end of the plunger 41 and the groove is engaged by pins mounted in the upper arm of a bell crank lever 46 (Figs. 1 and 5) mounted fast on a shaft 48 which rocks in bearings formed in a bracket 50. The other arm of said lever is movable over a segment plate 52 and carries a spring-pressed pin secured to a knob 54, the pin bein adapted to enter any one of a series of holes 55 formed in said plate. These holes are so spaced apart that when the pin 54 is in any one of them the head 42 of the plunger 41 will be in engagement with one of the four pairs of the members 40; and the arrangement is such that when the lever 46 is in the position in which it appears in Fig. 1 the pinion 26 and ear 3O ig. 5) are effective to drive the siaft 34 and consequently to operate the work feeding mechanism. This pair of gears gives the shoe its slowest feeding movement or, in other words, produces the shortest length of stitch. As the lever -16 is moved to withdraw the plunger 41 from the shaft 34, the

head 42 is moved successively into engagement with the different pairs of members 40 thus increasing the speed of the feeding movement of the work and thereby increasing the length of the stitches formed.

It will now be understood that the adjustment of the lever 46 controls the length of stitch and that the position of the prcsser foot 10 is controlled by the thickness of the work. The thread measuring mechanism shown is connected with these two elements so that a change in the position of either the presser foot 10 or the lever 46 is effective to change the length of thread delivered by the measuring mechanism to the stitching instrumentalities.

The thread T is led from the wax pot, or other supply, through a thread locking mechanism indicated at 56, (Fig. 2) over a pin 58 on the end of a thread pulling lever 60, through another thread lock 62 to a roll 64, (Fig. 1) and thence over the roll on the end of the take up lever 8 to the looper 6. The thread locks 56 and 62 are alternately actuated so that the thread is always under the control of one of these locking devices. The lock 56 comprises a stationary bracket 65 and a member 66 pivotally mounted in one arm of a rocker 67 so that it can tip in the same plane in which the rocker. tips. This rocker is pinned to a short \shaft 68 supported in a stationary bearing and an arm 69 is pinned to the o posite end of this shaft and carries a roll 0 (Fig. 2) which runs on the peripheral cam face 72 of the cam 73 mounted fast on the shaft 14. A

spring 74 acts on this arm 69 in a direction This member 7'6 co-operates with an upper spring pressed thread-engaging member 7 8, having a tongued portion to enter the groove of the part 76. and having its shank positioned in a hole 79,drilled in the machine frame. A coiled spring 80 encircles a reduced part of this shank and tends con-' stantly to hold the member 78 in engagement with its co-operating thread clamping member 76. The range of movement of the arm 69 and consequently of the rocker 67, is such that the thread clamp 56 is opened at certain times and closed at other times, but the thread lock 62 always remains closed, the rocking of the part 67 merely being sufficient to increase or decrease the grip of the members 76 and 78 on the thread.

The thread drawing movement of the lever 60 takes place while the clamp 56 is open. This movement is produced b cam connections including a link 83 whic connects the rear end of thethread ulling lever 60 with one arm of a bell cran lever 84, (Fig. 1), the other arm of which carries a roll 85 running in a path 86 of a cam fast on the shaft 14. This mechanism thus gives the lever 60 a stroke of fixed length.

The variation in the thread drawing action of this lever required to enable it to pull more or less thread depending upon a change in the thread requirements, caused by eithcr a change in the adjustment of the length of stitch or a variation in the thickness of the work, is produced by so mounting the lever 60 with reference to the thread clamps 56 and 62 that more or less of its stroke may be made eflective to draw thread from the supply. For this purpose the fulcrum 82 of the thread pulling lever 60 is mounted on one arm of a bell crank lever 88 which moves on a fixed fulcrum 89, Fig. 2, and the other arm of the lever 88 carries the fulcrum pin 90 of a'floating lever 92. A link 94, pivoted to the lower end of the floating lever 92 at 95, connects this lever with a pin 96 mounted eccentricall on one end of the rock shaft 48 on which t e stitch length adjusting lever 46'is fixed. Another link 96' pivoted to the upper end of the floating lever 92 at 97, connects this lever with one arm of a bell crank lever 98, the other arm of which is pivotally connected to the 'presser foot plunger 11.

It will now be understood that when the thread measuring operation-takes place, the rocker 67 will be ti ped about the axis of the shaft 68 in a cloc -wise .direction so as to open the thread lock 56 and to increase the grip of the thread lock 62 on the thread.

he cam connections of the lever 60 then rock this lever about its fulcrum 82 in a clock-wise direction (referring to Fig. 2) thus moving the pin 58 upward with reference to the thread locks and causing it to draw thread from the supply through the open thread lock 56. If desired two pins 99 may be positioned on the hub of the rocker 67, as shown in Figs. 2 and 6, to guide the thread as it leaves the thread lock 56 and enters the lock 62. These pins also render the thread measuring action more accurate. KVhen the thread drawin stroke of the lever 61) has been completed, t e cam path 72 permits the spring 14 to move the rocker 67 in a counter clock-wise direction thus closing the thread lock 56 and reducing the grip of the lock 62 on the thread. The sewing instrumentalities then draw the loop of thread just measured off through the lock 62, which acts during this 0 eration merely as a thread tension device. e thread lock 56 prevents the pulling of thread directly from the supply after the thread measuring operation has been completed, While the thread lock 62 operates during the thread measuring operation to prevent the pin 58 from drawing thread back away from the sewing instrumentalities.

It will be evident from an inspection of Fig. 2, thatrhanges in the position of the floating lever92, produced by changes in the thread requirements, act through the bell crank lever 88 to raise or lower the fulcrum 82 of the thread pulling lver 60, Consequently, whilethe actuating mechanism for this lever gives it a stroke of-fixed length, the part of this stroke that is effective to draw thread from the supply will be determined by the osition of the fulcrum 82 since, if this ulcrum point is raised or lowered, the limits of the reciprocating movement of the pin 58 will be moved up or downlongitudinally of the path of travel of the pin. Obviously, if the upper limit of this movement is raisedwith reference to the thread-locks, the pin will draw more thread from the supply at each thread measuring operation, and if lowered, it will draw less thread. Since theadjustment of this fulcrum is controlled by changes. in the length of stitch or in the thickness of the work the length of thread measured out in each cycle will vary with changes in these conditions.

Assuming, for intance, that the parts are in the relative positions in which they appear in Fig. 1 and that a thicker part of the work is moved underthe presscr-foot 10, the consequent raising of the .resser foot will act through the bell crank ever 98 and link 96' to swing the floating lever 92 about the pivot 95 as a fulcrum, and this change in the posi tion of the lever 92 will act through the pivot 90 and the bell crank lever 88 toraise the fulcrum 82 of the lever 60 and therefore cause this lever to measure off a longer length of thread. Similarly if the stitch length adjusting lever 46 is moved to position the pin 54 in one of the upper holes in the plate 52 to increase the length of stitch, this movement will be transmitted through the link 94 to the floating lever 92, moving the lower end of this lever forward about the pivot 97 as a fulcrum. and thus acting through the bell crank lever 88 to raise the fulcrum 82 of the thread measur ing lever 60 and increase the length of thread measured 0H. The increase or decrease. as the case may be, in the length of thread measured off will, of course, be proportional to the change in the length of stitch and thickness of the work. The thread delivering movement of the lever 60 and pin 58 is so timed with reference to the movements of the take up mechanism and the stitch forming instrumentalities that a substantially uniform tension is maintained on the thread between the thread measuring mechanism and the stitch forming members while a stitch is being formed. In other words, the part 58 is moved at such a speed that it delivers thread to the stitch forming instrumentalities at substantially the rate at which they require it and the presence of slack thread between these instrumentalities and the thread measuring mechanismi thus is avoided.

This thread measuring mechanism is very simple in construction, reliable in operation and is so constructed that it is not subject to wear or deterioration. It obviously is entirely automatic in its action and it measures thread very accurately. While I have herein shown and described the best embodiment of this invention of which I am at present aware, it is obvious that this embodiment may be departed from in many particulars within the skill of the mechanic and the discretion of the designer, without departing from the spirit or scope of this invention.

What is claimed as new, is

1. A thread measuring mechanism for a sewing machine comprising, in combination, a single thread pulling device mounted to have a to and fro movement, mechanism for imparting said movement to said device, and means for automatically varying the eflective thread pulling stroke of said device in accordance with changes in the length of stitch and the thickness of the work.

2. A thread measuring mechanism for a sewing machine comprising, in combination,

a thread pulling lever, mechanism for giving said lever a stroke of fixed-extent, threadengaging means co-operating with said lever, and mechanism for relatively moving said lever and means automatically in response to changes in the length of stitch or the thickness of the work to render more or less of said stroke effective to draw thread from the supply.

3. A thread measuring mechanism for a sewing machinev comprising, in combination, thread engaging devices mountedadjacent to each other and relatively movable to draw thread from a supply, mechanism for producing said relative threaddrawing movement, means-for adjusting the length of stitch, a member arranged to engage the work and to be moved into different ositions by changes in the thickness 0 the work, and connections between said adjusting means and said member constructed and arranged to cause a change in the length of stitch and in the thickness of the work to effect a change in the length of thread drawn from the supply by the relative movement of said devices.

4. A thread measuring mechanism for a sewing machine comprising, in combination, a cam actuated thread pulling device and automatic mechanism acting independently of the cam connections of said device to control the thread drawing action of said device in accordance with changes in the thread requirements for both the length of the stitch and the thickness of the work.

5. A thread measuring mechanism for a sewing machine comprising, in combination, two thread locking devices, a thread pulling member arranged to act on the thread between said devices, mechanism for giving said member a reciprocating movement of predetermined length, and mechanism for adjusting said member bodily to transfer the limits of its reciprocating movement longitudinally of the oath of said movement.

6. A thread measuring mechanism for a sewing machine comprising, in combination, a thread pulling member, means for reciprocating said member, thread engaging devices co-operating with said member to enable it to draw a measured length of thread from the thread' supply, and mechanism for adjusting the thread drawing stroke of said member comprising a lever connected with said member to adjust it and arranged to be moved by changes in the thread requirements for both the length of stitch and the thickness of work.

7. A thread measuring mechanism for a sewing machine comprising, in combination, a thread pulling member, means for reciprocating said member, thread engaging devices co-operating with said member to enable it to draw a measured length of thread from the thread supply, and mechanism for adjusting the thread drawing stroke of said member comprising a floating lever arranged to ad ust said member and connections whereby said lever is given an adjusting movement by a change either in the length of stitch or in the thickness of the work.

8. A thread measuring mechanism for a sewing machine comprising, in combination, a thread pulling member, means for reciprocating said member, thread locking devices co-operating with said member to enable it to draw a measured length of thread from the thread supply, mechanism for adjusting the thread drawing stroke of said member in accordance with changes in the thickness of the work and the length of the stitch and mechanism operatin in timed relationship to the movements 0 said member to actuate said locking devices alternately.

9. In a sewing machine, the combination with mechanism for adjusting the length of stitch and a device mounted for engagement with the work and arranged to be moved into different positions by changes in the thickness of the work, of a lever, means connecting said lever with said mechanism and said device constructed and arranged to move the lever upon a change in the thickness of the work or in the length of stitch, a thread pulling mechanism, and connections between said lever and said thread pulling mechanism arranged to enable the lever to control the length of thread drawn from the supply in each cycle by said thread pulling mechanism.

10. A sewing machine, having, in combination, stitch forming devices, and a single thread pulling device for drawing from the thread supply the exact length of thread needed for the thread requirements of the stitch forming devices both for the length of the stitch and the thickness of the work.

11. A sewing machine, having, in combination, stitch forming devices, and a single thread pulling device for drawing from the thread supply the exact length of thread needed for the thread requirements of the stitch forming devices both for the length of the stitch and the thickness of the work, and separate trains of mechanism for varying the efiective thread pulling stroke of said thread pulling device in accordance with changes in the length of stitch and the thickness of the work, res

In testimony whereof name to this specification.

EDWARD E. FOSTER.

ctively. have signed my Certificate of Correction.

It. is hsrehy wrtified that the State of incorporation of the assignee in Lotlvrs Pam-m No. 1367.284. granted hvptvmhvr 4, 1923, upon the applic-atimz nf' l'ldwa rd E. Fnstvr, of Beverly. B-Iassavhusvtts. fl an improvemvnt in 'lhrnud-Mvasul'in Mechanisms for Sowing ihn'hinvs." was orroneously given as Masszu-lmst-tls; whm'oas said State shullld have hm'n giwn as New York as .shown by tho rm'nlds of assignments in this otlivv: in theprintod spvnificution [mgr 4, lino 32. for tho misspollvd word intancn" road instrmw; same page, lim- 77. at'lvr the word [10" insert. the word rapid; and that the said Letters latvnt should he read with thaw- LtUI'ILCliUIlS th u-in that the sauna-may conform to the record of the was" in the Patent 0mm.

."-'rncl and S's-Med this 16th d:l nf October, A. D., 1923.

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