US1369414A - Thread-measuring - Google Patents

Description

E. E. FOSTER. THREADMEASURING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED MAY 28 I917.

Patented Feb. 22, 1921.

3 SHEETS-SHEET I.

Fig l /A/ VE/V 717 E. E. FOSTER. THREAD MEASURING MECHANISM FOR SEWING MACHINES.

. A P P L l C A T l 0 N F I L E D M A128. 1917. I

Q 3 SHEETS-SHEET Z- Fig 3 APPLICATION FILED MAY 28, I917- Patented Feb. 22, 1921 3 SHEETS-SHEET 3.

Mvemar M nnwanp nosrnn, or BEVERLY, MASSACHUSETTS.

THREADFMEASURING- MECHANISM FOR SI]7VING-JJIACIHIIITES.

Specification of Letters Patent.

Patented Feb. 22, 1921.

Application filed May 28, 1917. Serial No. 171,344.

To (all whom it may concern:

Be it known thatI. Enwann E. Fosrnn, 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-hilachines, 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.

Sewing machines and particularly those intended for use on relatively heavy work, such as harnesses, shoe soles and the like, are usually equippedwith a threadmeasuring mechanism designed to draw from the thread supply in each cycle of operations of the machine substantially the length of thread required for. a stitch. The present invention relates to mechanisms of this character and aims to devise a simple. accurate and thoroughly reliable thread measuring. mechanism adapted particularly part of to meet the requirements of sewing nachines designed to operate on heavy work.

It is obvious that the length of thread required in each cycle of operations of a sewin g machine willvary with the thickness of the work and thelength of the stitch made. The present invention therefore contemplates an arrangement which will automatically vary the length of thread supplied to the sewing instrumentalities in accordance with variations either in the thickness of the work or in the length of, stitch; but certainfeaturcs of the invention may be used to advantage in machines in which one only of these conditions. is taken care of automatically.

The invention willloe readily understood from the following descrip ion of the embodiment thereof now preferred by me and the novel features will be pointed out in the appended claims.

in the accompanying drawings Figure 1 is. a side elevation of the upper an outsole stitching machine equipped with a thread measuring mechanism embodying this invention;

Fig. 2 is avertical cross sectional view through certain partsof the thread measuring mechanism F 3 is a transverse vertical sectional.

view on the line 3-+3, -Fig. 2;

V needle in Fig. 4B is a side elevation of the thread measuring wheel;

Fig. 5 is a vertical cross sectional view on the line 5-5, Fig. 2;

.Fig. 6 is a vertical cross sectional view of the mechanism for adjusting the length of stitch of the machine shown in Fig. 1; and

Fig. 7 is a vertical cross sectional view taken substantially on the line 66, Fig. 6.

The sewing or stitching machine shown in the drawings forms the subject matter of pending application Serial No. 153,161. filed March 7., 1917 in the name of Charles C. Blake. A detailed description of this machine is unnecessary for the purpose of reciprocate toward and from a work support or throat plate 4, and a looper 6 which presents a loop of needle thread to the position to be caught by the hook of the needle and drawn up through the worl A loop thrower 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 presserfoot 10 mounted on the lower end of rod 11 which slides through the frame and is acted upon by a spring 12 to hold the presser foot 10 firmly in contactwith the work. A cam-operated 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 pressure 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. Thefeeding mechanism shown is of the charaeter disclosed in pending application Serial No. 113,724, filed August 8, 1916 in the name of Charles C. Blake. But, in the machine shown in the present application the horizontal shaft 19, which operates said mechanism, is driven by an adjustable mechanism by means of which the length of each feeding movement, and consequently the length of each stitch formed, can be adjusted. v

This driving mechanism is inclosed in housings 20 and 21 and is best shown in Figs. 6 and 7. 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 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 mechanical movement is fully disclosed in pending application Serial No.

786,909, filed August 27. 1913 in the name of Charles C. Blake. Four pinions indicated respectively at 26, 27, 28 and 29 (Fig. 6) are mounted fast on the shaft 25 and run constantly in mesh with gears indicated respectively at 30, 31, 32and 33, all looseiy mounted on the hollow shaft 34:. This shaft is connected through a universal joint with the shaft 19.

The respective pairsof 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 Fig. 7, 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. 7) are pivotally mounted in the hub 36 close to its periphery and they are provided with hook-shaped spring arms which enter slots formed in opposite sides of the shaft 3a 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 31 can rotate freely on the clutch. hub 36 without effecting 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 in order to render any one of the four gears shown effective to drive the shaft 3a, a clutch actuator is provided which consists of a plunger 41 carrying a head l2 which slides in the bore of the shaft 34. A handle 44 is fixed on the outer end of the plunger 4-1 and enables the workman to adjust the plunger to enable any desired pair of gears to drive the work support. The plunger is graduated, as shown in Fig. 6, to guide the workman in setting it properly. It will be evident from an inspection of F 6 and 7 that wh n the plunger is pushed inwardly to its farthest position the pinion 26 and gear 30 will be rendered effective to drive the shaft 34 and consequently to operate the work feeding mechanism. This. pair of gears gives the shoe its slowest feeding mo 'em'ent or, in other words, produces the shortest length of stitch. As the plunger ll is withdrawn from the shaft 3d the-head a2 is moved successively into engagement with the different pairs of members i0 and throws the clutches successively into action. The gear ratios are such that the speed of the feeding movement of the work and, consequently, the length of th stitches formed, is increased as the plunger is moved outwardly.

It will now be understood that thelength of the stitch made in a given cycle of opera tions. of the machine depend upon the extent of the rotative movement imparted to the shaft 34 in that cycle; and that the position of the presser foot 10 is controlled by the thickness ,of the work on which the stitch-forming instrumentalities are operating. The thread-measuring mechanism pro-. vided by this invention is connected with the shaft and the presser foot 10 so that a change in the thickness of the work or in the length of stitch is effective to change the length of thread drawn from the supply by the thread-measuring mechanism.

The thread T is led from a wax pot, or any convenient source of supply, over a thread controlling or feeding wheel d6 on to a guide roll 47 and then over another roll on the end of the take up lever 8 to the looper 6. variable speed mechanism which, in the construction shown includes a differential gear mechanism. is ar 'anged to give the thread feeding wheel d6 thread feeding movements in each cycle which, as above stated, are determined in extent by the thickness of the workand the length of stitch. The wheel is held stationary at other times and it is of such a construction that it grips the thread firmly and prevents any slippage of the thread over it due to the pull of the sewing instrumentalities. As clearly shown in Figs. 2 and d, the wheel 4:6 is mounted on the hub of one of the gears of the variable speed mechanism and it conof two plates 48 and 49 spaced slightly apart by a collar and clamped on the hub by a nut 51. The plates 48 and 49 each have a series of peripheral fingers which are spaced apart and bent so'that they cross each other, as clearly shown in Fig. 2, each finger of one plate extending through the space between the two adjacent fingers of the other plate. A V-shaped groove thus is formed around the periphery of the wheel by the intersections of the fingers and the thread T is placed in this groove and is given somewhat more than one complete turn around the wheel so that it cannot slip relatively to the wheel.

The differential gear mechanism above mentioned comprises two opposed bevel gears 52 and 53 mounted fast on co-axial shafts 54 and 55, respectively, that are arranged end to end and are supported in suitable bearing brackets mounted on the machine frame. An annular bevel gear 56 carries two stub shafts 57 and 58 projecting toward each other into the circular space at the center of'the gear and-they carry two bevel pinions 59 and 60, respectively, both of which mesh with the two bevel gears 52 and 53. A pinion 62 drives the annular gear 56 and is mounted fast on an upright shaft 63, to the lower end of which is fixed another pinion 64' meshing with a gear 65 that is mounted fast on the hollow shaft 34 of the mechanism that feeds the work. The angular movement imparted to the shaft 34 in each cycle is transmitted through the mechanism just described to the thread feeding wheel 46 and, since the gear 53 is held stationary at this time, this movement gives the wheel 46 a thread feeding movement of an extent proportional to the length of the work feeding movement, which, of course, determines the length of stitch.

The additional movement of the thread feeding wheel required to enable it to operate in accordance with variations in the thickness of the work is transmitted to the differential earing through the shaft which, for this purpose,-has fixed thereon the hub or cam 68 of a roll clutch. The hub, as shown in Fig; 3, is provided with four pockets 69, each designed to receive aroll 70, and this hub and the rolls are inclosed in a casing 72 which constitutes the actuating member for the' clutch. This member is mounted to rock concentrically with the gear 53 and a link 7 3 connects this member to one arm 74 of a bell crank lever fulcrumed on the machine frame at 7 5 and having another arm 7 6 carrying a roll that runs in a. cam path 78 formed in a cam that rotates with the shaft 14. The arm 7 4 is slotted and a block 7 7, mounted for adjustment in this slot. carries the pivot pin for the upper end'of the link 73. This block also is pivoted to the lower end of a link 79, the upper end of which is pivoted to the rearward end of a lever 80 that is fulcrumed on the machine frame at 81, see Fig. 1, and has its forward end pivotally connected at 82 to the presser foot rod 11.

It is obvious that the cam mechanism just described imparts a stroke of fixed extent to the lever arm 74 in each cycle; and the connection between the block 7 7 and the presser foot renders more or less of this stroke ef-v fective to move the clutch actuating member 72 as the thickness of the work increases or decreases. This clutch is so designed that practically all of the angular movement of the part 72 in one direction is transmitted through the clutch to the shaft and, since the gear 56 is held stationary at this time, the movement so imparted to the shaft 55 will be transmitted through the gear 53 and the pinions 59 and and the gear 52 to the thread feeding wheel 46 thus moving this wheel in the same direction that it is moved by the connections with the work feeding mechanism. The extent of this movement obviously will depend upon the thickness of the work since, when a thick piece of work is positioned between the presser foot 10 and the work support 4, the connections 80 and 79 will hold the block 77 at a point farther away from the axis of oscillation of the lever arm 74 than if a thin piece of work is being operated upon, and thus cause the cam 78 and lever 74 to produce a greater angular movement of the clutch actuator 72 than otherwise would be the case.

It is obvious that the pull of the take-up of the sewing instrumentalities on the thread will tend to rotate the wheel 46 and interfere with the thread measuring operation. In order to prevent any action of this kind a cam operated brake is employed which holds the shaft against rotative movement in the direction that the pull of the thread would tend to rotate it except during the period when this shaft is being positively moved by the connections with the cam 78. This brake mechanism com prises a disk or pulley 85 fixed on the shaft 55 and a friction roll 86 mounted loosely in slots formed in the bifurcated arms 87 of a bell crank lever that is fulcrumed on the shaft This roll is arrangedto wedge between the periphery of the pulley 85 and a stationary block 88, Fig. 5, secured fast to one of the bearing brackets. The other arm 89 of the bell crank lever is connected by a link 90 to the lower end of a lever 91 which is fulcrumed on the machine frame at 92, Fig. 1, and the upper end of this lever carries a roll that runs on the peripheral face 93 of a cam fast on the shaft 14; A spring 94. connected at one end to the machine frame and at its opposite end to the lever 91, holds the roll carried by the lever in contact with the cam face 93. This spring therefore normally holds the bell crank lever arm 97 in such a position that the roll 86 binds between the pulley 85 and the part 88 and prevents the shaft 55 from rotating in the direction that would permit a thread feeding movement of the wheel 46. The clutch members 68, and 72 prevent any rotative movement of the shaft 55 in the opposite direction. The cams 93 and 78 are so timed that the brake roll 86 is released at substantially the instant that the rotative movement of the clutch actuator 72 produced by the cam 78 is begun, and the brake is set again at substantially the instant that this rotative movement is completed. The only thread feeding movements that the wheel 46 can have, therefore, are those produced by the cam 78 and by the work feeding mechanism.

The work feeding movement takes place at the very beginning of the cycle of operations of the machine and consequently the thread feeding movement determined by the length of stitch takes place at this time. The thread feeding movement of the wheel produced by the mechanism controlled by the presser foot takes place very shortly there after, and the sum of these two movements is equal to the length of thread required for the stitch to be made in that cycle of operations of the machine. The entire thread feeding operation consumes only a very small fraction of the cycle. After the thread feeding operation has taken place the wheel 46 is held stationary during the remainder of the cycle and it locks the thread against any further forward movement while the stitch is being formed and set.

Since all of the driving connections for the thread measuring mechanism are positive in their action, this mechanism operates with great accuracy, and is very reliable. The construction illustrated also is entirely automatic in its action, any change in either the thickness of the work or in the setting of the mechanism to modify the length of stitch acting automatically to effect the required change in the thread measuring operation necessary to cause it to measure off the length of thread required by the changed conditions.

It is obvious that the detailed construction of the thread measuring mechanism will vary with the character and design of the machine in which it is used and that the invention therefore is not limited to the details of the construction shown.

What is claimed as new, is:

1. A thread measuring mechanism for sewing machines comprising, in combination, a thread feeding device, and operating means therefor including a. variable speed driving mechanism for said device, controlled in its action both by the length of stitch and the thickness of the work.

2. A thread measuring mechanism for sewing machines comprising, in combination, a thread feeding device, differential gearing arranged to drive said device, and means acting through said gearing to cause it to give said device a thread feeding move ment in each cycle of an extent determined automatically by the thickness of the work and the length of stitch.

3. A sewing machine comprising the combination with stitch forming mechanism, a presser foot and work feeding mechanism, of a thread measuring mechanism comprising a thread feeding device and variable speed mechanism for operating said device controlled in its action jointly by said presser foot and by said feeding mechanism.

4. A sewing machine comprising the eombination with stitch forming mechanism, a presser foot and work feeding mechanism, of a thread measuring mechanism comprising a thread feeding device, differential gearing operative to drive said device, and means connecting said gearing with said presser foot and also with said work feeding mechanism, said means being constructed and arranged to cause said gearing to give said device a thread feeding movement in each cycle of an extent substantially proportional to the thickness of the work and the length of the stitch.

5. A thread measuring mechanism for sewing machines comprising, in combination, a. rotatable thread feeding device, and operating mechanism forsaid device constructed and arranged to cause it to feed, in each cycle of operations of the machine, a length of thread determined by the length of stitch and the thickness of the work.

6. A thread measuring mechanism for sewing machines comprising, in combination, a rotatable thread feeding device, and operating means for said device including a variable speed mechanism and intermittingly acting actuating mechanism therefor, said operating means being controlled in its action by the thickness of the work.

7. A thread measuring mechanism for sewing machines comprising, in combination, a rotatable thread feeding device, and intermittently acting driving mechanism for said device constructed and arranged to give said device a thread feeding movement in each cycle of operations of the machine of an extent determined automatically by the thread requirements forthe length of the stitch and the thickness of the work.

8. A thread measuring mechanism for sewing machines comprising, in combination, a rotatable thread feeding device and positively acting actuating mechanism for said device constructed and arranged to give said device a thread feeding movement in each cycle of an extent which is varied automatically wlth changes in the length of stitch and the thickness of the work.

A thread measuring mechanism for sewing machines comprising, in combination, a rotatable thread feedingdevice and positively acting operating means for the device including a variable speed mechanism controlled by the. thread requirements for the length of the stitch and the thickness of the work.

10. A thread measuring mechanism for sewing machines comprising, in combination, a rotatable thread feeding device and operating mechanism for said device inclnding a differential gear mechanism arranged to drive the device and positively acting power-driven means controlled automatically by the thread requirements and constructed and arranged to drivev said device throughsaid differential gear mechanism.

, 11. A sewing machine comprising the combination with a stitch forming mechanism, a presser foot and work feeding mechanism of a thread measuring mechanism comprising a thread feeding device and operating mechanism for said device includingdiiferential gearing arranged to drive the device, connections between one member of said gearing and said work feeding mechanism operative to give said device a thread feeding movement in each cycle substantially proportional to the length of stitch, and additional connections. between another member of said gearing and said presser foot constructed and arranged to give said device" an additional thread feeding movement of an extent varying-with the thickness of the work.

12. A thread.measuring'mechanism for sewing machines comprising, in combination, a rotatable thread feeder and operating mechanism therefor including a rotatable shaft connected with said feeder to drive it, adriven cam, connections between said shaft and cam operative to give the shaft ,rota-tive movements in one direction only, and meanscontrolled by the thickness .of the work for controlling the extent of each rotative movement imparted to the shaft'by said connections. 7

13. A thread measuring mechanism for sewing machines comprising, in combination, a rotatable threadfeeder, and operating mechanism for said feeder including dif ferential gearing arranged to drive the feeder, and two driving connections for said gearing operable through different members of the gearing, one of said connections being controlled by the length of stitch and the other by the thickness of the Work.

14. A sewing machine comprising in combination, a stitch forming mechanism, means for adjusting the length of stitch, a rotatable thread feeding device, and operating mechanism for said device constructed and arranged to cause it to feed in each cycle of operations of the machine a length of thread varying with the thickness of the work, said operating mechanism including connections with said stitch adjusting means whereby changes in the length of stitch will effect corresponding changes in the length of thread fed by said device.

15. A sewing machine, having, in combination, stitch forming mechanism and a work support relatively movable to transfer the point of operation of the stitch forming mechanism around thework, means for adjusting the length of the transferring step,

' a rotatable thread feeding device, and oper

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