US2517567A - Sewing machine control mechanism - Google Patents

Description

Aug.8,1950

Filed June 21, 1947 G. HILL ET AL SEWING MACHINE CONTROL MECHANISM 1 III" m I I I b? is; 9 Q4 5 a WIIIIHIIHI A I! R? Q II llml IIIIIIIH l I I II In";

8 Sheets-Sheet 1.

INVENTORS GILBE'RT H/L L T ATTORNEY G. HILL. ETAL 2,517,567

SEWING MACHINE CONTROL MECHANISM Aug. 8, 1950 FJEZ INVENTORS GILBERT HILL h CLINTON 0e W/TT BY k TT'OR/VE Y Aug. 8, 1950 Filed June 21, 1947 G. HI LL mum.

SEWING MACHINE CONTROL MECHANISM l"" I i .IN V EN TORS GILBERT H/LL H. 0L 4 TON W/TT B 1 1 52,

ATTORNEY Aug. 1950 G. HILL ETAL 2,517,567

SEWING MACHINE CONTROL MECHANISM Filed June 21, 1947 8 Sheets-Sheet '7 INVENTORS GILBERT H/LL H. CLINTON DeW/TT T TORNE Y 8. 1950 G. H m1. 2,517,567

sswms MACHINE CONTROL MECHANISM Filed June 21, 1947 8 Sheets-Sheet a M0 INVENTORS GILBERT HILL H CLINTON DfiW/TT Patented Aug. 8, 1950 UNITED STATES PATENT OFFIC E snwmo v aonmc CONTROL 'YMECHANISM poration :of'New "York Application June: 2-1,

. 20 Claims. ,1

This invention relates to sewing machine control-mechanisms, and especially to control mechanisms for sewing machines of industrial type adapted to operate on work ,of considerable :length and breadth, such as quilts and com- .forters, which often require stitching along irregular paths in order to trace out intricate designs.

The invention constitutes an improvement on the sewing machines disclosed and claimed in US. Patents #1931491, #1346368, and #2377,- Z95.1,,issuedlNovember 28, .1933, February .13, 1934,

,and J one .12, 1945 respectively, to Walter H. May,

though inmajor part the improvement is applicable to a variety of types of sewing machines, as will be apparent to those skilled in the art.

In the aforementioned patented sewing machines of Walter H. May an open framework of cylindrical or drum-like configuration is provided as a movable mount or holder for the work to be operated upon by the sewing mechanism. ,Such mount or work-holder is rotatable about its 1ongitudinal axis, and is slidable back and forth axially, thereby permitting substantially univerparticularly susceptible to inadvertent movesal movement of the work relative to the sewing head and other parts of the sewing mechanism. It is adjustable lengthwise, enablingit to receive a variety of sizes of quilts, comforters, or like work of unusual size not readily accommodated 3 ,mentioned heretofore being eliminated.

by ordinary sewing machines. Such work is held securely by the cylindrical work-holder while an operator manipulates a control handle to properly rotate the work-holder backwardly and forwardly and move it longitudinally fromside mechanism :is'brought to a stop.

to side for guiding and feeding the work into the sewing mechanism along whatever irregular and intricate paths may be required. A foot pedal is provided, enabling the operator to control the speed of the electrically driven sewing mechanism while manipulating the control handle. The sewing mechanism proper is, for the most part, of conventional construction.

Sewing machines embodying conventional sewing mechanisms suffer from the fact that, when the sewing mechanism is stopped following any operative run thereof, the needle may come to rest at any position within its reciprocative cycle. Thus it may and frequently does come to rest in a downward position, making it impossible to remove or alter the position of the fabric being sewn, without damaging the same by the needle .or even breaking the needle, until the needle is raised to its highest position by suitable manipulation of the sewing mechanism. Furthermore, before thefabric being sewn can be removed 1947, .Serial No. risen;

from the machine or its position altered therein, the tension normally maintained on the sewing threadlduring the sewing operation must be relieved. This is conventionally accomplished by 5 suitable lever action occurring coincidentally with the lifting by the operator of the presser foot Pursuant to the present invention means are provided whereby the needle ,is automatically raised clear of the work being operated upon (thereby insuring the completion of a full stitch anddisengagementof theneedle from the sewing hook) and the tension on the sewing thread is automatically relieved whenever the sewing mechanism is brought toa stop. Thus, the work .beingoperated upon may befreely moved at ,any .time the sewing mechanism proper is stopped, without .danger of injuring either the work or .the machine. This ,i a great advantage for sewing machines in general, but is especially advantageous in con- ,nection with the special May machine outlined above, since the cylindrical work-ho1der,'bal- .anced as it is, for convenient manipulation, is

,ment. An important feature ofthe present invention in this connection is the provision for complete control of the machine by means of the aforementioned control handle, the foot pedal Accordingly, it is an object of the invention to provide for automatically bringing, the needle of .a sewing machine to rest free and clear of the work being operated upon, whenever the sewing j It is an object to provide for the completion of af fullstitch whenever the needle is brought to rest, so the needle is free of the sewing hook when at rest.

;It is an object to provide for automatically relieving the sewing threadof tension whenever the, sewing mechanism .is brought to a stop.

, .It ,is .an object to provide for the above in a sewing .machine equipped with a cylindrical Work-holder adapted for substantially universal movement relative ,to the sewing mechanism proper, the control being exercised through the .handleby which the work-fhQlder is manipulated.

It is a further object to accomplish the above by relatively simple, positive-acting,mechanism .not likely to getout oforder.

,These .,and other .objectsand features of the invention will be fully dealt with inthe following detailed description of the presently preferred as specific embodiment illustrated in the accompanying drawings by way of example of the generic concepts here disclosed and claimed.

In the drawings:

Fig. 1 illustrates in front elevation a machine for sewing intricate designs in quilts and comforts, being of the general type disclosed in the aforementioned U. S. patents of Walter H. May, but constructed in accordance with the present invention;

Fig. 2 is a side elevation looking from the right, this view being drawn to a slightly enlarged scale;

Fig. 3 is a fragmentary vertical section taken on the line 33, Fig. 1, showing portions of the control handle mechanism in elevation, the view being drawn to a considerably enlarged scale;

Fig. 4 is a fragmentary horizontal section taken on the line 44, Fig. 1;

Fig. 5 is a fragmentary vertical section taken on the line 5-5, Fig. 3;

Fig. 6 is a greatly enlarged fragmentary vertical section taken on the line B-6, Fig. 2;

Fig. 7 is a somewhat enlarged fragmentary vertical section taken on the line Fig. 6, illustrating the friction clutch in front elevation;

Fig. 8 is a section on line 8-8, Fig. 7;

Fig. 9 is a section taken on the line 99, Fig. 6, showing important parts of the needle-raising mechanism in elevation, the position being that assumed when the sewing mechanism is at rest;

Fig. 10 is a fragmentary View corresponding to the upper portion of Fig. 9, but illustrating the position of the parts during sewing operations;

Fig. 11 is a similar view illustrating the position of the parts after deceleration of the sewing head drive shaft to a speed substantially equal to the speed of the auxiliary motor;

Fig. 12 is a diagrammatic view corresponding generally to Fig. 9 where the sewing mechanism is at rest, the view being fragmentary and drawn to a somewhat reduced scale, and including a showing of portions of the interconnecting linkage;

Fig. 13 is a similar view showing the relative positions of the several parts at a stage intermediate the oif and the on positions of the control handle;

Fig. 14 is a similar View showing the relative positions at the stage of disengagement of the sewing mechanism from the main driving motor where the control handle is at on position;

Fig. 15 is a, somewhat enlarged fragmentary horizontal section taken on the lines 15-45, Figs. 1 and 2;

Fig. 16 is an enlarged fragmentary vertical section taken on the line |6|6, Fig. .1, showing the sewing head in detail with cover plate removed and needle in raised position, the tension discs being positioned to relieve the sewing thread of tension;

Fig. 17 is a fragmentary side elevation of the structure appearing in Fig. 16, the view being taken from the left;

Fig. 18 is an enlarged detail drawn in perspective and illustrating operating components of the thread tensioning and releasing mechanism of the immediately preceding figures, the parts being shown in their tension release positions;

Fig. 19 is a view corresponding to that of Fig. 18, but illustrating the several parts in their thread tensioning positions;

Fig. 20 is a longitudinal detail section through the conventional thread-tensioning portionv of Fig. 16 as it appears in the operating position of Fig. 19; and

Fig. 21 is a fragmentary elevation illustrating a modification wherein the auxiliary motor is replaced by a drive connection with the main motor.

Referring to the drawings: The machine as here illustrated embodies a rigid supporting framework, comprising a pair of mutually spaced end standards 20, to which are firmly secured a main longitudinal I-beam 2|, a secondary longitudinal I-beam 22, and a longitudinal angle beam 23. A truss-like arrangement 24 of structural members serves as reinforcing and balancing means to prevent vibration of the machine during operation.

A cylindrical or drum-like work-holder framework which provides a carriage for receiving and retaining the work to be operated on is indicated generally 25, and here comprises mutually spaced circular spiders 26 connected longitudinally by rods 21 which are telescopic so the carriage is rendered capable of accommodating quilts and comforts of different sizes. As in the aforementioned patents of Walter H. May, especially the latest one, No. 2,377,951, outer work-receiving rings 28, Fig.4, rotatably mounted on the rims of respective spiders 26 to move in synchronism with each other, provide the rotatable part of the cylindrical work-holder carriage 25. The circular spiders 26 are not themselves rotatable, but are suitably mounted on the trackway provided by main longitudinal beam 2|, see Fig. 3, for free sidewise movement in either direction longitudinally of the machine. Thus the work, securely mounted on such work-holder carriage 25, is freely movable substantially universally relative to other parts of the machine.

The movement of work-holder carriage 25 is controlled, as in the said prior patents, by means of a control handle 29 which is a rod-of telescopic construction for purposes of carriage size adjustment-extending longitudinally at the front of the machine so as to be constantly in the hands of the operator who is watching and guiding the progress Of the sewing operation. Such control handle forms part of a counterbalanced rocker frame rotatably mounted about the same longitudinal axis as the work-holder carriage 25. The rocker frome is indicated generally 30, and comprises a pair of mutually spaced and oppositely disposed transverse rocker arms, indicated 3|, respectively, which are suitably journaled at their mid-portions for rotative movement about the hubs 26a of respective spiders 26, see Fig. 3, and which have upstanding bracket extensions 3 la at their forward ends, serving to rotatably receive and carry control handle 29, and their rear ends interconnected by a rod 32.

The rocker frame 30 is normally freely rotatable in either direction with respect to the workholder carriage 25, and is so balanced as to normally rest in a horizontal position. When the operator of the machine desires to rotate the work in either direction relative to the sewing mechanism. he first pushes the control handle 29 inwardly toward the machine for the purpose of actuating suitable grab mechanism to temporarily connect such control handle with the workretaining rings 28 of the work-holder carriage 25. The grab mechanism here comprises a pair of grab shoes 33, Figs. 3 and 4, operably carried by respective blocks 33| pivoted to the forward portions of the respective rocker arms 3|, and normally held out of gripping engagement with annular grab rail portions 28a of the respective work-retaining rings by means of respective springs '34". Respective. bell cranks pivoted to the upstanding bracket extension 321 of the rocker frame 30 transmit the backward. movement of control handle 29; when the same is pushed by the operator as aforesaid; to the pivoted blocks 33--l through respective levers 36, thereby forcing such grab shoes 33 into frictional engagement withtheirrespective grab rails 28a. Thus all sectors of the work may be selectively brought under the immediate control of the operator.

The sewing mechanism of the machine comprises a sewinghead 31; Fig. 1, which in certain essential operating respects is of conventional construction. It is mounted substantially cen trally of themachine on a suitable bracket extending from the secondarybeam 23. The sewing mechanism further comprises conventional looptaking means 38; which includes a sewing hook and a properly housed bobbin. Such loop-taking means is mounted on secondary beam 22 directly below the sewing head. It carries a bed plate 1-39, which is supplemented by a work-tensioninghoop 4!] expansible and retractible circumferentially by suitable manually operable means 4| gener ally similar to that set forth in aforementioned Patent No. 2,377,951 of Walter H. May, and, therefore, not dealt with here in detail.

An electric motor 44 serves to drive sewing head 3? and loop-taking means 38 through respective drive shafts 45 and 46, Figs. 1 and 6, the drive pulley of electric motor 44 being belted to driven pulley 41, which is fixed to a countershaft 48 rigidly coupled to sewing head drive shaft 45. A suitable synchronizing gear drive, including a suitable countershaft 49, Fig. 6, connects countershaft. with a second countershaft 50 rigidly coupled to drive shaft 46 of loop-taking means 38.

As illustrated in Fig. 6 the main drive shafts Miami 46, both of which are of extended length, may be encased by respective continuous bearing sleeves 5| and 52 of. flexible material, such as commercial flexible shafting,'or by the usual rigid shafting. A bracket 53, Fig. 1', supports the drive shaft 45, while a standard (not shown) supports the drive shaft 46.

A manually actuatedelectric switch 55, Fig. 1, controlling the electric supply circuit to electric motor 44 is disposed in proximity to the sewing head 37, so the operator may energize and deenergize the machinewithout leaving the control handle 29.

Actuation of the sewing mechanism to carry out any given guided sewing operation under positive manual control of the operator is accomplished by the operator through the control handle 29 by which he exercises said positive manual'guiding of the sewing operation. For this purpose the power output shaft of electric motor 44 is coupled to the drive pulley shaft 56 thereof, see Fig. 15,.by means of a conventional variablespeed clutch and brake arrangement, indicated generally 51, operable from control handle 29 by suitable connecting mechanism. The entire variable speed drive unit, including motor, may be purchased from the Singer Manufacturing Co.

Control handle 29is rotatably mounted at its opposite ends in respective sleeve portions 3lb, see Figs. 4 and 5, which extend horizontallyfrom theupper ends of respective upstanding. bracket extensions Sla of the rocker frame 30, and the aforementioned connecting; mechanism includes a sprocket 58 fixed to that endiof' the control handle-which is nearest the motor'44; Such con meeting mechanism comprises, further, a pair of sprockets 5Qand6fl, see Figs. 1; 2} and 3;.r'otat ably supportedatithe pivotal'juncture of linkage arms 51 and62, a sprocket 6'3 fixed'to a rectan'J- gular countershaft 6'4" at the pivotal. connection of linkage arm*62"with.the hub of the particular spider 26concerned, seeespeciall'yjl 'igs. 3andi4fi a link arrangement 65? eccentrically, pivotedto end piece G la" or countershaft 64, which is journaled in a standard 20l; see especially Figs. 1- and2, a connectinglink fi'fipivoted'to' the par ticular end standardZW concerned, and-a second connecting link filsuitablyconnected'to the actu atingwarm-Ela of" the variable speedarr'angement 5T, see especially Figs; 2 and' 11. Sprocket 58 drives sprocket Bil-by means of a sprocket chain 68; sprocket Bib drives sprocket 6'3, and therewith countershaft 64; by means of a sprocket? chain 69; and countershaft" 64 operates the actuating arm 51a ofthe variable" speed arrangementbymeans of the above-describedconnecting, linkage.

Rotation of control handle zafrom' the "one position illustrated, at which" clutch and brake arrangement 57 completely'disengages the sew ingdrive mechanism from drive motor 44, effects engagement of such clutch and brake arrangement 5l with drive motor 44, and, as the rotation progresses accelerates the speed of operation of the sewingmechanism from a minimum to a maximum. Reverse rotationdecelerates until'the control'handle is again at itsoff'positi0n.

The mechanism for automatically'bringing'the sewing needle 'lfiof the sewing head 31; seeFi'g. l, to rest at predetermined position, preferably that high point in its oscillatory path at which the final stitch has been fully tightened, when the sewing mechanism is disengaged? from the main drivingmotor 44; is associated with the sewing head countershaft 48 largely within a housing ll 1 This housing rests on the secondary beam22 at the motor end of the machine, and is suitably securedto the supporting framework.

The aforesaid automatically operable. mechanisin includes a constant speed electric motor. 72- independent of but auxiliary to the main drive motor 44. Such auxiliary motor 12" is mounted outside the housing TI" on a bracket support 13, and serves to drive'througha suitable gear reducer (not illustrated) an auxiliary countershaft 15 at a relatively lower speedthanthe normal operating speeds of the sewing mechanism, preferably at approximately 110R; P. as compared withfrom 2000 to 3000 R. P. Mcof the sewing head drive. The power output shaft 16 of such motor andgear reducer is coupled to auxiliary countershaft l5by means of a. friction clutch H hereinafter described'in detail.

Auxiliary countershaft T5 is journaled in. the housing ll below andsubstantially parallel with sewing head countershaft 48, and is arranged to drive the latter whenever the rotative speed thereof falls below a minimum speed.

To this end governor means are providedLthe same taking the form of a pawl andlratchetarrangement' embodying a ratchet 19, see especially. Fig. 9, affixed to the hub of a sprocket wheel 18. whichis mounted for freerotation on sewing. head countershaft 48 as an axis. A disc 851s. fixed to said countershaft 48 for rotation .therewith in immediate adjacency to the ratchet),- anda pawl 8| is carried by disc on a stud. 82 protruding from the appropriate face. offdisc 80,.see Figs. 9, 10 and 11'. The stud 82 is received by a relatively short slot 83 through the bodyof. paw18l adjacent one endthereofl The opposite amt-. 1

toothed end of the pawl is normally held in engagement with ratchet hub 19 by a spring 84, but is made heavier than the slotted end, so that, when the sewing head countershaft 48 and therefore the disc 80 carried by it is rotate-d at a speed substantially greater than the said minimum, the pawl is disengaged from the ratchet hub against the urge of spring 84 by reason of centrifugal force acting on the relatively heavy toothed end of such pawl. A pin 85, protruding like stud 82 from disc 80, serves as an outward limit stop for the pawl 8| when in disengaged position, as just explained, by the action of centrifugal force. In this disengaged position of the pawl, the disc 80 rotates entirely free of the sprocket-ratchet combination l8 and #9, see Fig. 10. This is the condition that exists during normal operation of the machine where the sewing mechanism is actually sewing the work fed to it by the operator.

It should be noted that, during this time, auxiliary motor I2 is driving auxiliary countershaft I5 through friction clutch IT. A sprocket wheel 86, fixed on the auxiliary countershaft I5 for rotation therewith, drives sprocket wheel I8 and the ratchet I9 by means of an interconnecting sprocket chain 81 at the aforesaid minimum speed, which is determined by the drive ratio between the two sprocket wheels 89 and I8.

When the operator rotates the control handle 29 to the off position, thereby disengaging the drive mechanism of the machine from the main motor 44, as afore-explained, the speed of sewing head drive shaft 45 and its countershaft is quickly drops below that of the auxiliary countershaft I5, as does the speed of disc 89 below that of ratchet I9. Accordingly pawl 9|, no longer maintained erect by centrifugal force, drops inwardly toward the center of disc 89 and is pulled backwardly by spring 84 so that its toothed end engages positively with ratchet hub I9, see Fig. 11. Disc 80 and the entire sewing mechanism are therefore driven positively by auxiliary motor I2.

'It will be note-d that the slotted end of pawl 8|, terminates in a finger 8I'a, which, when the toothed end of said pawl is in engagement with the ratchet hub I9 as just described, extends farther outwardly from the center of disc 89 than otherwise. As so positioned such pawl finger 8 Id is adapted to engage switch-actuating and stop mechanism.

The latter mechanism comprises an intermediately pivoted carriage I43 having at one end a shock-absorbing stop portion, which normally extends into the path of rotation of the pawl finger Bla in the above-described pawl-engaged position thereof. Such stop portion includes a shroud 88 holding an upwardly-projecting strike plate 89 backed by a rubber pad 99. Carriage I43 is mounted on a rockshaft 9I which extends transversely of the housing H, being journaled therein and in a supporting bracket 92. Rockshaft 9I projects outwardly of the housing H, and has an actuating arm 93 fixed thereto.

' Carriage I43 is arranged for limited movement transversely of the axis of rockshaft 9!, and for this purpose receives the rockshaft in a somewhat enlarged bore I43-I, Fig. 9, having narrow extensions, x, x. Fins 9Ia, 9Ia from rockshaft 9I have a sliding fit in such narrow slot extensions at, as, and serve to support carriage I43 so that it has freedom for limited forward and backward sliding movement.

A spring 94 normally'biases the carriage away from the pawl-carrying disc 99, holding it against a stop-screw 95 adjustably secured in standard 92 to limit downward movement of the carriage. As so biased, carriage I43 is held so that the rockshaft 9| is located at that end of the enlarged bore I43I which lies nearest the stop portion of the carriage, thereby affording a very limited, resiliently retarded movement of the carriage, in the direction of strike, to the opposite position illustrated in Fig. 9. This provision for limited, resiliently retarded movement, together with the shock-absorbing action of the rubber pad 90, affords abrupt stopping of the sewing mechanism without injury to the machine when the finger 8Ia of the pawl engages strike plate 89.

Accordingly it is seen that, following disengagement of the main driving motor 44 from the main drive mechanism by the operators rotating of the control handle 29 to its off position, the auxiliary motor I2 takes over automatically and continues to positively operate the sewing mechanism through any incompleted portion of a full needle oscillation. That is to say, with the strike plate disposed so as to positively halt the sewing mechanism at the highest point attained by the needle in an oscillation thereof, the auxiliary motor I2 will always carry on the movement of the sewing mechanism until the strike plate stops it at that desired predetermined needle position.

The auxiliary motor 12 is energized by a local electric circuit controlled by a single pole, doublethrow electric switch 95 whose switch-actuating arm 9! is resiliently pressed against a pin 98 projecting from the carriage I43. When the carriage is in its normal spring-biased position, switch 95 is closed to energize auxiliary motor "I2. Upon such movement of carriage I43 as is permitted by the enlarged bore I43-I when pawl finger 8Ia strikes strike plate 89, the switchactuating arm 9! is moved by pin 98 to open the auxiliary-motor-energizing circuit controlled by switch 95 and thereby to de-energize auxiliary motor I2.

Friction clutch 1! coupling drive shaft I6 of auxiliary motor I2 to auxiliary countershaft I5 is provided to limit to a safe value the torque produced by the sudden deceleration of such auxiliary motor 12. It comprises coacting clutch members, see Figs. 7 and 8, one of which is a cupped disc I00 fixed to the drive shaft I6. The I other clutch members are grouped about the countershaft I5 and fitted within cupped disc I90. They comprise a pair of opposing friction shoes IDI forced radially outwardly of the rotative axis and against the internal circumferential surface of cupped disc I00 by means of a pair of springs I02 whose tension is adjustable by means of respective nuts I93 threaded on respective studs I94. A pin I05 extends diametrically through hub 86a of sprocket 86 and through countershaft 15, its end portions fitting into receiving slots I06 of the respective friction shoes I0! for the purpose of loosely coupling such friction shoes to countershaft 15 for rotation therewith. Adjustment of nuts I93 may be made as desired for establishing the operating characteristics of the clutch.

Electric switch 96 also controls a local electric circuit governing the action of the threadtension release mechanism of the invention, maintaining such circuit open when the aforementioned auxiliary motor circuit is closed and vice versa.

Such thread-tension release mechanism is illustrated in Figs. 16, 17, 18, 19, and 20 in connection with the conventional sewing head 31 *9 and loop-taking means 38. It comprises a solenoid- IIO .having a plunger III operatively connected to a conventional thread-tension device indicated generally H2. The latter embodies customary tension discs I I3 held in tension position, see1Fig..20, by the springs U4 and H5 during sewing operation of the machine, and further, a tension release pin 1 I6slidable within a sleeve III.

For transmitting the movement of solenoid plunger III to tension-release pin H6 a floating lever bar H8 has one end .pivoted to solenoid plunger l I I by meansof a pivot stud II9 extending rigidly from an arm IZIIfixed to the solenoid plunger, see Figs. 18and 19. The opposite end of such lever bar IIB is fixed to a shaft I2 I ,which passes through and is :journaled by a casing wall of a bracket 3'I-I. Fixed to the opposite end of shaft I2l, within a recess of the sewing head, is an actuating arm I22, and extending into a receiving slot I23 of such arm I22 is one end of an actuating pin I24. Such actuating pin extends into sleeve In of the thread-tension device I I2, and works againsttension release pin H6, serving to push it forwardly when the solenoid is energized and solenoid plunger III raised, see Fig. 18, and thereby presses against the outer tension disc II3 thus extending the distance between said tension pdiscs II3 against the urge of springs I4 and H5, to release the tension on the thread in the customary manner.

It should be noted that the operation of the abovedescribed tension-release mechanism for the sewing thread is entirely automatic. Upon stopping of the sewing needle III at the predetermined rest position, thethread tension is automatically released. This is brought about by reason of the fact that the pivoted stop carriage I43 .is caused to actuate switch 96 to close the local electric circuit governing solenoid I I0, thereby energizing the solenoid, whenever thesewing mechanism is brought to'a stop .in the aforedescribed manner.

Renewed tensioning of the thread is eifected at the commencement of a subsequent sewing operation by reason of the action of control handle 29 on the stop carriage I43 and of the latters action on switch- 96.

Following any cessation of workby the opera tor of the machine, sewing operation is resumed by the rotating of the control handle '29 counterclockwise from the off position of Figs. 1, 2, and3. Such rotation of'the control handle acts on the variable clutch means 51, through sprocket chains 68 and '69, the rectangular countershaft 64, and linkage 65, 66, and 61, to connect the sewing head driving mechanism with the main motor 44. It also acts through additional interconnected linkagetomove stop carriage I43 to disengage its strikeplate 89 from the finger 8Ia of pawl SI prior to commencement of operation of the sewing mechanism.

Such additionallinkage comprises a link I25, Fig. 2, connected at one of its ends to .the stop carriage actuating,arm. 93 and at the oppositelend totheend piece-64a of countershaft64,.1eccentrically, in common with link 65, ,see especially Fig. 12.

The: linkage; is. arranged to provide a slightitime delay between disengagement of strike vplate-89 fromipawl SI and engagement ofithe sewingvhead drive :mechanism with the main motor '44. To this endthepivotedconnections of link I25 with actuating armneii. andrwith link 65 through i end 10 piece-64--I, as well-as-the pivotal connection rof link 65 with lever 66 are of pin and slot type.

In the off position of Fig. 12,established by an arm I26 which extends from endpiece 64-4 and rests against limit stop pin I21 projecting from the face of standard 2Il-I, the pin I28 ;of actuating arm :93 is disposed approximately at the lower end of slotl29 of link I25, and the pin I36 of end piece 64--I is disposed at the upper end of slot I3I of link .65. 'Ihelpin I32 of lever 66 is, disposed at the upper end of slot 1:33 of link 65. Accordingly, when theoperator turns control handle 29 and therewith end piece .,64--,I counterclockwise from off position toward on position as indicated by the appended arrow,,actuating arm 93 is moved upwardly to dip the stop portion of carriage =81 downwardly so stop ,plate 89 clears pawl ill, see Fig. ,13. ,During this ,time pin I32 rides freelyin its s1ot.l33 untilit reaches the lower end thereof. As turning of .control handle 29 toward ion position continues, link 65 acting throughits pin I32actuates leverSGto engage the sewing drive mechanism with main motor 44, see Fig. 1.4. By this timestopplate 89 is well out of the rotative path of pawlfll, and the disc may rotate freely. The action of the linkageisjust the reverse ,when control handle is turned clockwise fromthe on position of Fig. 14 backto the oifiposition of Fig. 12.

It is advantageous .that link 65 be ,provided with asection 65-4 arranged ,topermit length adjustment, thereby enabling the linkage to be adjusted to accord with other operativeparts of the machine.

A manuallyoperatedpresser foot I34, .Fig. 51, is provided in the customary manner, ,withthe exception that manual operation thereof by the handle I35, Fig. 16, and attached actuating arm I36, effects conventional tensioning andtension release of the thread onlyas an auxiliaryto the normally automatically acting means of the invention, afore-described. Pursuant to the invention the tension of the sewing thread is relieved automatica ls without raising the presser foot.

Reverting for a moment to the auxiliary power drive previously described, the gear reducermentioned as associated with the auxiliary motor .12 is preferably a self-locking type so the pull of the springs 84 and 94, as effective on drive shaft 48, will not cause unwarrantedrotation of. such drive shaft and consequent ill-timed disengagement of pawl 8| fromits stop 89.

If desired, the main motor 44 may perform the functions of the auxiliary motor 12. In such an instance auxiliary countershaft 15 will-becomnected, through clutch 11, to a suitable take-off drive from main motor 44, it beinglunderstood that, with the arrangement illustrated, the main motor 44 continues to turn while the sewing mechanism-is disengaged therefrom and at rest. Asillustrated inaFig. 21, the take-off, drive of this form of auxiliarypower driveembodies a jack shaft I49 driven by an elongated-portion 44a of the drive shaft of main drive motor 44, and a secondaryjack shaft I4I geared to a gear reducer I42 of the self-locking type above mentioned. Within the gear reducer or at any othersuitable location there is provided ,a solenoid-operated clutch arrangement (not illustrated) which is engageable and disengageable under the electrical control of switch 96, the control-arrangement being such that the take-off drive will be ineffective duringsuch times as in the prior .embodiment when the auxiliary motor I2 would be shutoff.

It should be realized that while the control mechanism of the invention isv illustrated and described in novel combination with a power sewing machine embodying a work-holder and a control handle for guiding the work-holder relative to the sewing mechanism, specifically the previously patented May type of power sewing machine, the several sub-combinations involved in the larger inventive combination may be used in power sewing machines generally. Furthermore, such sub-combinations may be usefully employed in a variety of types of machines where the result sought is the halting of an oscillating or other cyclically moving part at a predetermined position within its movement cycle following the shutting ofi of power to the machine.

Whereas this invention is here illustrated and described with respect to a preferred specific construction, it should be understood that various changes may be made in such specific con struction and various other constructions may be developed on the basis of the teachings hereof by those skilled in the art without departing from the generic scope of the invention as defined by the following claims.

We claim:

1. In a power sewing machine embodying sewing mechanism, power drive means therefor, =a work-holder, and a control handle for manually guiding the work-holder relative to the sewing mechanism, the combination of auxiliary power drive means normally disconnected from said sewing mechanism; a. governor arranged to perably connect said auxiliary power drive means with said sewing mechanism when the main power drive means decelerates below a given minimum speed; stop means associated in predetermined relationship with said governor and adapted to be engaged b the latter for halting the sewing mechanism at a predetermined position following drive connection with said auxiliary power drive means, thereby predetermining the rest positions of the sewing needle and cooperative sewing hook; means operably interconnected with said control handle fo disengaging said stop means from said governor means upon given manipulation of said control handle; and means also operably interconnected with said control handle for controlling the operation of the main power drive means.

2. The combination recited in claim 1 wherein the governor comprises a pawl and ratchet combination including resilient means normally holding the pawl in engagement with the ratchet, the pawl being mounted on a shaft of the power drive means for rotation therewith and the ratchet being interconnected with the auxiliary power drive means for rotation therewith, the pawl being weighted to disengage from the ratchet under the influence of centrifugal force at and above a given minimum speed of rotation of the said drive shaft on which it is mounted.

3. The combination recited in claim 2 wherein the pawl embodies a finger which projects for engagement with the stop means when the pawl is in engagement with the ratchet.

4. The combination recited in claim 3 wherein the stop means embodies a cushioned stop member for absorbing the shock of sudden stopping of the sewing mechanism.

5. The combination recited in claim 4 wherein the stop means comprises a pivoted carriage carrying the stop member at one end portion thereof, and wherein the disengaging means comprises a lever operable at the opposite end portion thereof.

6. The combination recited in claim 5 wherein the pivoted carriage is mounted for slight longitudinal movement backwardly and forwardly and is resiliently biased backwardl from the path of action of the pawl finger.

7. The combination recited in claim 6 wherein the disengaging means further comprises linkage connected to the lever and connected with the control handle so the stop member may be disengaged from the pawl finger by operation of the control handle.

8. The combination recited in .claim 7 wherein the control means for the main power drive comprises linkage interconnected with the linkage operating the stop means, said linkage embodying time delay means effective to delay actuation of the main power drive until after disengagement of the stop means.

9. The combination recited in claim 8 wherein the work-holder is of substantially cylindrical formation and mounted substantially horizontally for rotation backwardly and forwardly and for longitudinal movement from side to side; wherein the control handle is in the form of a rod extending substantially coextensively longitudinally with said work-holder at the front thereof and arranged to be manipulated by an operator for moving said work-holder as required by the particular sewing operation concerned, said rod being rotatable; and wherein drive means :connect said rod with the control linkage so that rotation of the rod effects control of the sewing mechanism.

10. The combination recited in claim 9 wherein means under control of the stop means is provided for operating the thread tensioning device of the sewing mechanism.

11. The combination recited in claim 10 wherein the auxiliary power drive means embodies an electric motor energized by a local electric power circuit; and wherein an electric switch maintains said circuit closed during operation of the machine but is arranged to be opened by stopengaged movement of the stop carriage.

12. The combination recited in claim 11 wherein the operating means for the thread tensioning device comprises a solenoid and energiz ing electric circuit therefor; and wherein the electric switch closes the said solenoid circuit on the throw which opens the auxiliary motor circuit.

13. In a power sewing machine having main power means, a power-driven sewing needle and sewing hook, the combination of a cylindrical work-holder adapted to retain on its circumferential surface an article to be sewn, said workholder being rotatable about its longitudinal axis as a center and slidable longitudinally to move the work relative to the sewing needle; normally balanced handle means for guiding, under manual control, said work-holder relative to said sewing needle; and auxiliary power means for automatically raising the sewing needle to a high point free and clear of its cooperative sewing hook upon the halting of any sewing operation.

14. The combination recited in claim 13 wherein there is additionally provided means cooperating with said needle raising means for automatically relieving the thread of tension upon the halting of any sewing operation.

15. In a power sewing machine embodying sewin mechanism including a sewing needle and cooperative sewing hook, a main power drive means; auxiliary power drive means normally disconnected from said sewing mechanism; a governor arranged to operably connect said aux l a y power drive means with said sewing mechanism when the main power drive means decelerates below a given minimum speed; stop means associated in predetermined relationship with said governor and adapted to be engaged by the latter for halting the sewing mechanism at a predetermined position following drive connection with said auxiliary power drive means, thereby predetermining the rest positions of the sewing needle and cooperative sewing hook; means for disengaging said stop means from said governor means; and means operably interconnected therewith for controlling the operation of the main power drive means.

16. In a power sewing machine embodying sewing mechanism including a sewing needle and cooperative sewing hook, a drive motor; a drive arrangement adapted to transmit motion from the drive motor to the sewing mechanism; means for engaging and disengaging said drive motor relative to said drive arrangement; an auxiliary drive motor; a governor associated with said drive arrangement; a secondary drive arrangement interconnecting the auxiliary motor with said governor, the latter being arranged to cut in said auxiliary drive motor to said drive arrangement when the speed of the latter decreases below a predetermined minimum; stop means arranged for engagement by a part of said governor following cut-in of said auxiliary motor; a switch operated by said stop means for shutting off said auxiliary motor; and means for disengaging said stop means from said governor following the shutting off of said auxiliary motor.

17. In a power driven machine having a driven element arranged for repetitive movement along a cyclic path, main power drive means adapted to transmit motion to said driven element; auxiliary power drive means also adapted to transmit motion to said driven element; a governor associated with said main power drive means, said governor having engaging means arranged to be effective at a given deceleration of said main power drive means; engageable means associated with said auxiliary power drive means for driveimparting engagement with said engaging means when the latter becomes effective; and stop means disposed in predetermined position and adapted to engage said engaging means when the latter becomes effective, thereby halting said driven element in a predetermined position within its said cyclic path.

18. The combination recited in claim 17 wherein an electric switch is associated with the stop means, and wherein electrically actuated means are arranged to effect actuation of the auxiliary power drive means, said switch being arranged to control actuation of said auxiliary power drive means.

19. The combination recited in claim 17 wherein the engaging means comprises a slotted, pin-limited pawl, and the engageable means comprises a ratchet wheel, said pawl being carried by said main power drive means.

20. The combination recited in claim 17 wherein the engagin means comprises a slotted, pin-limited pawl having a projecting stop-engaging finger, and the engageable means comprises a ratchet wheel, said engaging means being disengaged by centrifugal action.

GILBERT HILL. H. CLINTON DE WITT.

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

UNITED STATES PATENTS Number Name Date 1,850,708 Davis Mar. 22, 1932 1,926,604 Terry Sept. 12, 1933 2,376,648 Anderson May 22,1945 2,377,951 May June 12, 1945

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