US2430440A

US2430440A - Presser-bar mechanism for sewing machines

Info

Publication number: US2430440A
Application number: US629363A
Authority: US
Inventors: Frederick F Zeier
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1945-11-19
Filing date: 1945-11-19
Publication date: 1947-11-04
Anticipated expiration: 1964-11-04
Also published as: DE824429C

Description

Nov. 4, 1947;v F. F. zElER PRESSER-BAR MECHANISM FOR SEWING MACHINES Filed Nov. 19, 1945 5 Sheets-Sheet l Nov.44, 1947. F. F. Z'EIER `2,430,440

PRESSER-BAR MEGHANISM FOR SEWING MACHINES Filed Nov. 19,1945 5 sheetssheet 2 PRESSER-BAR MECHANISM-FOR SEWING MACHINES Filed Nov. 19, 1945 5 Sheets-Sheet 5 Nov. 4, 1947-. F. F. zEn-:R

`PRESSE'R-BR MECHANISM FOR SEWING MACHINES Filed Nov. 19, 1945 5 sheets-sheet 4 album,

(redem'c leier l I9 mi la... DM

NOV. 4, 1947. F, F, ZIER 2,430,440

' PRESSER-BAR MECHANISM FOR SEWING MACHINES Filed Nov. 19, 1945 5 sheets-sheet 5 79 v 105 16? er .136 zal Patented Nov. 4, 1947 UNITED STATES PATE-.NT "DEFI-CE PRESSER-BAR. MECHANISM FORSE-WING MACHINES Application November 19, 1945,tSeria1No. 629,363

23 Claims. 1 This invention relates to sewing machines and, more particularly, to means for raising a presserbag and/or an upper four-motion feeding mechanism off the sewing machine work-support.

The usual `sewing machine is equipped with some type of a work-presser mechanism which is urged toward the work by means of a spring. vWorking in cooperation with the work-presser or presser-foot mechanism for the purpose of feedingthe work past the stitching mechanism is the usual lower four-motion feed-dog. This feed-dog commonly traverses an elliptical path which has its major axis substantially parallel to the sewing machine throat-plate. The feed- `dogfis positioned relative to the throat-plate so that, when the feed-dog is traversing the upper portion of its path, the feed-dog teeth will project above the top surface of the throat-plate. Therefore, during the first half of the feeding movements of the feed-dog, when the dog is above the top surface of the throat-plate, the feed-dog .will move both upwardly and in the direction offeed, thereby to grip the work against the presser-foot and actually lift the presserfoot and presser-bar a short distance. During the latter half of the feeding movement, the feed-dog moves both downwardly and in the direction of feed before dropping below the top surface of the throat-plate. The downwardly spring-biased presser-foot and the presser-bar drop with the feed-dog until the down-movement of the work is arrested by the throat-plate. The work then remains stationary while the feed-dog returns below the level of the upper face of the throat-plate to its initial position' to begin another feeding stroke. 'Ilhese engagements of the feed-dog with the work usually occur once for each stitch made by the machine, and the presser-bar and foot must rise and fall with the feed-dog once for each stitch.

Due to the movement of the feed-dog in the direction of feed, the work is drawn under the sole portion of the presser-foot, thereby introducing a sidewise thrust which sets up frictional forces between the presser-bar and its bearings and thus this frictional force, coupled with the natural inertia of the usual presser-bar, tends to prevent the presser-bar from returning quickly to its lower position when the feed-dog moves downwardly.

As the speed of a sewing machine is advanced, it |becomes increasingly difcult to return the presser-foot quickly and forcibly down upon the -work at the end of the feed-advance stroke of the feed-dog. At these higher speeds of operati-on oftherma'chine, thefriction between the presser-bar and its bearings isrincreased .duetto the increased speed. ofthe Work under the presser-'foot `sole portion, and this (friction, coupled with the inertia of the machine parts builds up to the `extent lthat the spring which is used-to return or lower thefpresser-b'ar: cannot function to lower completely the presser-foot between con- Vsecutive `Work.-disengaging Vand work-engaging movements of .the feed-dog.

'Sewing vmachines having Yan upper four-motion feeding mechanism of the: character known `as the alternating presser type` alsopresent substantially: the same. .problem `as that hereinabove discussed. .In this type of mechanism, there is employed an automatidpresserand feeding-foot .lifting mechanismwhich fisnormally dependent upon theresistance imposedlby thework or its 4support to thedownward movement of either .the presser-foot or feeding foot, in orderto .provide a fulcrum for lifting the other of said members. Therefore, if any.inertia Vor cramping of the parts occasions a sufficient resistance before 4either of said members in its descending movementireaches the work, .the necessary fulcrum will be untimely provided and neither ofsaid members will engage the work with the requisite `pressure toinsure a proper Work-feeding action. -Theliabilitynf imperfect operation of feeding mechanisms of vthis character increases withthe speed of operation of the machine, due ina largemeasure rto inertia ofthe `parts and also becausethe spring which depressesthe .presser and feeding foot elements cannot recover with sufficient rapidity to overcomethe upward movements'thereof. At extreme vhigh speeds, a degree of Ainefoiency maybe reached `wherein neither the presser-foot nor the feeding-foot perceptibly engages the work.

One method Vof overcoming the above discussed difficulties is toprovide the mechanism, whether it be of the usual simple presser-bar or olf the upper four-motion feeding type, with a spring capable ,of exerting a force materially greater 4than `that .heretofore used. Although the addition of this spring helps to obviate the one difiiculty, it was found `that thenecessary force of the spring required excessive manual effort `to lift thepresser-footoff the work. Even if the machine operator could exert the requisite amount of force to lift the presser-bar, she would soon tire `of such arduous work. It has been found that an operator can, with comfort, continue to `operate a presser-bar lifting device if the maximum 'force required does not exceed ten pounds. However, many of the present type sewing machines require a spring force of about fty pounds in order to urge the presser-foot against the work with the requisite force to properly feed the work at all different speeds of operation of the machine.

It is, therefore, an object of this invention to provide a sewing machine with presser-bar lifting means which will require a minimum of force to operate.

Another object of this invention is to provide an improved means for applying to and removing spring pressure from a work-presser mechanism.

With the above and other objects in View, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several` features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

Fig. 1 represents a rear side elevation of a sewing machine in which the present invention is incorporated.

Fig. 2 represents a top plan View, partly in section, of the present machine.

Fig. 3 represents a left side elevation of the sewing machine, showing the stitching and feeding mechanisms with the bed and work-supporting plate in section, and with the needle in its uppermost position.

Fig. 4 represents a left side elevation of the stitching and feeding mechanisms as removed from the sewing machine frame and with the needle in its lowermost position.

Fig. 5 is a detail view, in elevation, of the feed-lift crank in its raised or inoperative posi. tion, with the lock-pin device sustaining the crank in this position.

Fig. 6 represents a sectional View of the upper feeding and stitching mechanism taken substantially along line 5--6 of Fig. 1.

Fig. 7 represents a sectional View of a portion of the feedand presser-bar actuating mechanisms taken substantially along line 1-1 of Fig. 3.

Fig. 8 represents a sectional view showing a portion of the presser-bar with its associated elements and taken substantially along line 8-8 of Fig. 6.

Fig. 9 represents a sectional View showing a feed-bar lifting means and taken substantially along line 9-9 of Fig. 6.

Fig. 10 represents a sectional view showing the presser-lifting mechanism in its normal position and taken substantially along line IfI--IU of Fig. 2.

Fig. 11 represents a detailed view of that Geneva stop mechanism which actuates the spring-disengaging toggle mechanism.

Fig. 12 is an illustration in side elevation of the presser-lifting mechanism at that point in its cycle at which the presser spring is fully relaxed.

Fig. 13 represents an enlarged detailed view in side elevation of the fulcrum member and the presser-bar lifting arm which is engaged thereby.

Fig. 14 is an illustration of the presser-lifting mechanism at that point in its cycle at which the presser-bar and top feed-bar are fully raised 01T the work.

Fig. 15 represents a detailed view of a portion of the presser-lifting mechanism taken substantially along line I5-I5 of Fig. 1 and showing the 4 mechanism at that point in its cycle corresponding to that illustrated in Fig. 12.

Referring to the drawings, the invention is embodied in a sewing machine having a frame comprising a bed I6 from one end of which rises a standard I1 of an overhanging bracket-arm I8 terminating in a head I9. Journaled for rotation within this frame is a main-or arm-shaft 2D carrying at its outer end the usual belt-driven balance-wheel 2I and at its inner end a counterbalanced needle-bar actuating crank 22. Shaft 20 is connected by a clip-belt 23, herein shown incompletely, to a belt-pulley 24 fast upon the outer end of a lower mainor bed-shaft 25 journaled for rotation in the bed I6, the ratio between the

shafts

20 and 25 being one-to-one.

Actuated by the bed-shaft 25 is the usual lower four-motion work-feeding mechanism, including a feed-dog 25, and the looper mechanism including a chain-stitch looper 21. For the sake of brevity, a detailed description of the four-motion feeding mechanism will not be given herein, inasmuch as the same is fully described and claimed in my U. S. Patent No. 2,292,258, Aug. 4, 1942.

With regard to the looper mechanism disclosed in the drawings, it will sulce to say that the looper 21 is preferably of the two motion type having loopseizing and shedding movements only in the line of feed, the looper advancing to seize the needle-loop in a direction opposed to the direction of feed.

Referring now to the mechanism within the machine-head I9, it will be seen in Figs. 1, 3 and 4 that a needle-bar actuating link 28 is pivotally mounted upon the crank 22 by means of a screw 29. The lower end of the link 28 is apertured to receive a pin 30 integral with a split collar 3I clamped upon the usual needle-bar 32. Carried at the lower end of the needle-bar 32 is a suitable needle 33. Through the mechanism just described the needle-bar 32 is reciprocated endwise in proper timed relation with the complemental looper 21 to produce chain-stitches.

The needle-bar 32 is journaled in bearing

members

34 and 35 projecting from the needle-bar frame 36 which is provided with a horizontally projecting fulcrum-rod 31 journaled within the lug 38 of the machine head I9.

The needle-bar-frame 36, in the machine illustrated, is oscillated in timed relation with the four-motion feed-dog 26 through mechanism comprising a rock-lever 39 (see Fig. 1) preferably clamped at its lower end 40 upon the end portion of the fulcrum-rod 31. At its upper end, the rock-lever 39 is pivotally connected, by means of a bolt 4I and nut 42 to one end of a relatively short pitman 43 formed at its other end with a strap 44 embracing an adjustable eccentric 45 secured to rotate with the arm-shaft 29. It will be understood that as the arm-shaft 29 is rotated, the eccentric 45 actuates the pitman 43 which in turn operates the rock-lever 39 to oscillate the needle-bar-frame 36 about the axis of the fulcrum-rod 31. The amplitude of oscillatory movement imparted to the needle-barframe is dependent upon the amount of eccentricity of the eccentric 45 and, in order to vary the amplitude of the oscillatory movements of the needle-bar frame to harmonize with the stitch-length to which the lower feeding mechanism is set, the eccentric is made adjustable. A complete description of this type of adjustable eccentric may be found in the U. S. patent of W. Myers, No. 2,128,031, Aug. 23, 1938. For a more detailed description of the present type of needlebar mechanism, reference may be had to my U. S. Patent No. 2,329,681, Sept. 14, 1943.

Referring particularly to Figs. 3 and 4, the needle-bar frame 36 has a vertically apertured bearing lug 116 formed thereon adjacent the bear- 5 ing portion 35. Slidably mounted within this bearing lug l' is a top feed-bar 41 carrying at its lower end a feeding foot 98 which is adapted to cooperate with the needle 33 and the lower feed-dog 26 in the feeding of the work over the bed-plate 49. Since the feed-bar 41 is carried by the needle-bar frame 36, the latter element will impart the same amplitude of vibrating motion in the line of feed to both the needle-bar 32 and the top feed-bar 41.

The upper end of the top feed-bar d1 is provided with a cross-pin 59 which is slidingly received within the forked free end 5I of a substantially horizontally disposed feed-lift lever 52. The conned end of the lever 52 is pivotally mounted upon a fulcrum-pin 53 which is secured within the lower rear portion of the machine head I9.

In order to prevent the feed-bar 41 from turning about its longitudinal axis, the top portion thereof is provided with a pair of cheeks 59 which carry the cross-pin 50 and which embrace the forked portion 5I of the lever 52.

The machine head I9 is provided with a Vertically disposed stationary bearing member 55 in which a presser-bar 55 is slidingly mounted so as to be located slightly rearwardly of the top feed-bar 41 and out of the line of feed at that side of the line of feed nearest to the machine bracket-arm I 9. A usual type of presser-foot 51 is carried by the lower end of this presser-bar 55. Formed in the up'er portion and between the ends of the presser-bar 55 is a slot 58, Fig. 8, A

adapted to receive the free end of one arm 59 of a bell-crank lever which is pivotally carried by and at the center of percussion of the feedlift lever 52.

This bell-crank lever comprises the above noted arm 59 carried by one end of the pivot pin 69, to the other end of which is secured, by means of a screw 6I, a second arm 52 which is pivotally connected by a pin 63 to the lower end of a link 915. The pin 50 passes through the apertured bearing portion 65 of the lever 52 whose center of percussion lies along the axis of bearing portion 55.

The upper end portion of the link 64 is connected by means of a pin 56 to an actuating crank 91 carried by one end of a rock-shaft 68 which is journaled in bearing lugs 59 and 1i) provided on the machine bracket-arm I3 and h'ead I9, respectively. T'he rock-shaft 66 is disposed in parallelism with the needle-bar actuating shaft 29.

Secured upon the opposite end portion of the rock-shaft 68, by means of screws 1l, is a short crank 12 carrying a pin 15 which is pivotally e-mbraced by the forked end of a pitman 14 whose other end terminates in an eccentric strap 15. Strap 15 embraces an adjustable eccentric 15 secured to rotate with the arm-shaft 29. It will be understood that as the arm-shaft 29 is rotated, the eccentric 16 actuates the pitman 14 which, in turn, imparts rocking movements to the rock-shaft 58 through the medium of the crank 12. The amplitude of these movements may be varied by adjusting the throw of the adjustable eccentric 15. For a more complete description of an adustable eccentric of this type, reference may be had to the U. S. patent of A. H. De Voe, Reissue No. 14,218, Nov. 28, 1916.

Pressing downwardly upon the feed-lift lever 52, at a point between the bell-crank pivot point and the forked end 5I thereof, is one end of a spring-biased blade-lever 11 which is located outside of and rearwardly adjacent to the machine bracket-arm I8. The other end of this lever 11 is biased upwardly by means of a coil spring 18 which is operatively connected to an arm l'I9 mounted upon the bracket-arm I9. The lower end of the spring 18 is pivotally connected to the lever 11 by means of a bolt 80 and nut BI. As illustrated more particularly in Figs. 6, 9 and 10, lever 11 is fulcrumed adjacent to the feed-lift crank 52 upon a knife-edge 82 of a-fulcrum-piece 93 extending from a, stub-shaft 84 which is rockably mounted within an aperture 35 (Fig. 6) formed in the lower portion of the machine head I9. In order to prevent the spring-biased lever 'l1 from exerting any side thrust upon the feed-- lift lever 152, a steel ball 89 is held, by means `of a sheet metal cage 81, between said lever 11 and crank 52. The cage 81 is secured to the crank 52 by means of screws 88.

Referring particularly to Figs. 6 and 9, the lever 11 is apertured so as to afford clearance for a guide-pin 89 projecting upwardly from the shelf portion 99 of the head I9 and extending through the forked end of a guide-arm 9| which is clamped -by means of a screw 92 to the upper reduced portion of the presser-bar 59. Thus the presser-bar 56 is prevented from turning about its longitudinal axis and at the same time the pin 89 prevents the lever 11 from moving sidewise.

The oscillatory motions of the above noted rockshaft 58 cause the bell-

crank lever

59, 92 to swing in a vertical plane about its pivot pin 50 in the feed-lift lever 52, so that the arm 59 thereof successively tends to lift and depress the presser-bar 55. When the presser-bar 56 is depressed, however, its presser-foot 51 engages the throat-plate 93, or the work carried thereby, and further movement of the bell-crank lever can only result in raising the pivot point thereof, which latter action will, of course, raise the forked end 5I of the feedlift lever 52 with the consequence that the top feeding-foot 48 is lifted clear of the throat-plate 93, as is illustrated in Fig. 3. Continuous oscillation of the rock-shaft 68 will, therefore, cause the presser-bar 56 and the top feed-bar 41 alternately to rise and fall, and the spring-biased lever 11 being in continuous engagement with the feed-lift lever 52, it will have its force transmitted to either the presser-bar or to the top feed-bar, depending upon which one of the two elements is in engagement with the throat-plate or work. 'I'he motions of the rock-shaft 68 are synchronized with those of the needle-bar 32 so that the usual compound feeding motions will be effected.

Adjustment of the rock-shaft actuating eccentric 16 will effect adjustment in the amplitudes of the relative vertical movements imparted to the presser-bar and top feed-bar.

As hereinabove noted, one end of the lever 11 is pivotally secured to the coil spring 19 by means of the bolt 89. Referring more specifically to Figs. 1, 2, and 10, the lower end of the spring 18 is secured to the lower cup-shaped member 94 which is telescopically tted within the upper and reversely directed cup-shaped member 95 rwhose upper portion has a threaded rod 96 projecting upwardly therefrom. Clamped upon the rod 96 is a split collar 91 having a threaded bolt portion 98 extending laterally therefrom. Pivotally embracing the bolt 98 is the arm 10 held upon thev bolt by means of nuts 09. rIhe upper end of the spring is suitably secured to the member 95, thus to bias the lever 11 upwardly. The two cupshaped members and 95 form a substantially airtight unit whose purpose is to dampen the violent spring vibrations which would otherwise occur when the spring 'l0 passes through its critical phases. A rubber spacer |00 is disposed within the spring to limit lateral vibrations thereof.

The applied pressure of the spring 18 may be varied by shifting the rod 95 relative to the clamp collar 91, when loosened, by means of a stop-nut |0| which is carried by the threaded upper portion of the rod 90. The clamping screw |02 is used for tightening the collar d1 about the rod S8 in the set position of the collar.

Referring particularly to Fig. 10, the fulcrum point 82 of the spring-biased lever 11 is so located that the lever is of the iirst class; the portion thereof extending forwardly of the fulcrum point .82 being very much shorter in length than that portion which extends from the lever pivot point at 80 to the fulcrum point at 82. By means of the lever, or multiplying means 11, the amplitude of vertical movement of the feed-lift lever 52 is, in a preferred form of the device, multiplied by ve at the effective end of the lever 11, thus to impart to the lever a force ve times greater than the spring would impart thereto if it were acting directly upon the lever. Thus, a relatively light spring is adequate for supplying the proper pressure to the presser-foot and top feeding foot. Tests have proven that by using such a multiplier, superior results have been attained as compared to the results attained when using the same top feeding and presser elements but with a spring having about ve times the stiffness of spring 11 and applied to bear directly upon the lever 52. Apparently there is much advantage to be gained by using a light weight spring coupled with a multiplier as compared to using a heavier weight spring which is applied directly upon the lever 52. These tests have shown that the use of the present multiplier mechanism completely obviates the tendency of the feet d8 and 51 to flutter when the machine is operating at a high rate of speed. It is an advantage to use a spring having a high natural frequency for this purpose.

From the above description it is to be understood that through the medium of the lever 11, the spring exerts a tremendous force upon the lever 52. To raise the feet 08 and 51 against this force would require a rather awkward and impractical mechanism, or one that would require the application of a manually exerted great force. The present invention is applied to the above described machine for the purpose of providing a manually operable presserand top feed-bar lifting means designed to keep at a minimum the lifting force required. Broadly, these means comprise elements adapted, under treadle-controlled action, to render the coil spring 18 ineffective and to relatively shift the knife-edge fulcrum 82 and the spring-biased lever 11 to permit the presserand feed-bars freely to be raised of the work.

.Specically the present lifting mechanism comprises a self-contained frame member |03 secured to the standard l1 by means of the screws |04 which are threaded directly into the standard. Projecting inwardly from two sides of the member |03 is an edge portion |05 (Fig. 2), whichV functions partially to enclose the mechanism contained within the unit, Upon this frame are mounted two sets of Geneva stops geared together in order to provide a series of successive motions all produced by a single downward movement of the usual foot-actuated treadle (not herein shown) which is connected to the Geneva stops by means of a chain |06 and a pivoted arm or manually operable member |01, to which the chain is secured by means of a stud |08. The arm |01 is pivotally carried upon a shaft |09 entering an aperture ||0 provided in the frame |03. The free end portion of the arm |01 has a lip portion upon the end of which is carried, by means of screws H2, a segment-gear ||3. This segment-gear ||3 meshes with a gear I Ill mounted upon a rockable stub-shaft |5 and secured by means of screws ||6 to a Geneva driving element ||1 which in turn is secured upon the shaft ||5 by means of a set screw ||8.

Carried by one end portion of the element |1 is a pin ||9 adapted to slidingly enter a slot |20 of a Geneva driven element |2| which is mounted, by means of a set screw |22, upon a rockable shaft |23 journaled in ,a portion |24 of the frame |03 (see Fig. 15). Mounted upon that end of the shaft |23 remote from the element ||1 is a crank |25 carrying at its outer end portion a pin |26 upon which is pivotally mounted the lower end of a substantially upright link |21. The upper end portion of the link |21 carries a pin |28 which connects the link to a toggle joint comprising the double arms |29 and |30. Arms |30 are pivotally mounted upon a stud |3| carried by the frame |03 and arms |29 are pivotally connected, by means of a pin |32, to arm |33 which is pivotally mounted upon a shoulder stud |34 carried by the frame |03. The hereinabove noted arm 19 is integral with arm |33 and therewith forms a bell-crank lever which is connected to the spring-carrying rod 96.

From the above description, it is to be understood that, responsive to an initial downward movement of the treadle-chain |06, the segment gear ||3 will turn gear H4, thereby carrying the pin ||9 upwardly to eilect an upward movement of the slotted portion of the element |2|. As the driven element |2| turns about its axis, it rocks the shaft |23 which, in turn, will rock the crank |25 upwardly and elevate the link |21. This upward movement of the link |21 will flex the toggle joint, thus to swing the arm 19 of the bell-crank lever downwardly to the extent that the spring 18 will be completely relaxed. rIhis completely removes downward force upon the feet 08 and 51. By using a forcemultiplying means such as the present toggle joint for rendering the spring 10 ineiective, little force is required to be exerted upon the link |21.

Fig. 10 illustrates the present lifting mechanism in its normal condition, with the toggle arms |29 and |30 in their straightened position and with the spring 18 fully distended, to the end that it exerts its pressure upon the ball 86. Fig. 1'2 illustrates this mechanism when the toggle is broken and the spring is completely relaxed.

Pivotally mounted upon the stud |34 and adjustably secured to arm 10, by means of a set screw |35, is an arm |35 having a cam portion |31 thereon which is adapted to engage a plunger 30 for the purpose of releasing the tension between the disks |39 of a usual type of needlethread tension unit. The cam is adapted to engage the plunger only when the arm |36, swings to the position shown in Fig. 12.

Although the initial downward movements of the chain |06 and arm |01 were effective to relax the spring 18, it will be seen from Fig. 12 that there is very little clearance between the lever 11 and the fulcrum point 82, and as a consequence the fulcrum point 62 must be removed before the presser-bar 56 can be raised any appreciable distance above the throat-plate. Therefore, mechanism has been provided in the present device for the purpose of swinging this fulcrum point out of the path of lever move ment.

Referring to Fig. 12, it will be seen that further movement of the treadle chain will not move the bell-crank and coil spring 18, as the pin |I9 will merely swing clear of the slot |26 and the circular portion |46 of the driver ||1 will engage the corresponding circular hollow I4| provided in the driven element I2I and thus lock the element 42| in the position shown.

The forward end portion of this rock-bar |52 is also provided with teeth |55 adapted to mesh with gear teeth |56 provided on the end portion of the above noted stub-shaft 84 which carries the knife-edge 82Y and, therefore, any forward linear movement thatl may be imparted to the rock-bar will be effective to rotate the stub-shaft 64, thereby to remove the fulcrum point from the spring-biased lever 11for the purpose of providing proper clearance between the lever 11 and the fulcrum so the lever 52 may be freely raised.

Threaded into the fulcrum-piece 83 of the stub-shaft 64, at a point eccentric to the axis of rotation thereof, is a screw l|51 of which an exposed shoulder portion |58 (see Figs. 6, 9 and 13) enters a slot |59 provided adjacent one end portion of a sheet metal arm |66, the other end cf which is pivotally secured to the under body of the machine bracket-arm I8 by means of a screw |61. The free end of the arm |66, adjacent the slotted portion thereof, is bent to form a lip E62 underlies the guide-arm 9| carried by the presser-bar 56. A turning motion of the stubshaft S4', therefore, throws the screw |51 in an arcuate path, thereby raising the free end portion 0f the sheet metal arm |66 which, in turn, lifts the presser-bar 56. This upward movement of the presser-bar lifts the top feed-bar 41 also, through the medium of the bell-

crank lever

59, 62 which is -pivotally carried bythe feed-lift lever 52.

Referring to Fig. 13, it is ,to be understood that the slot |56 is arcuate in shape and disposed at an angle such that an initial turning movement of the stub-shaft 84, in the direction indicated, will be effective to drop the arm |66 slightly, thus to introduce a slightJ time delay before the arm is lifted, to the end that the fulcrum point 82 will 10 be removedv from the lever 11 before the bar 56 is raised.

Referring now to Fig. 10, which illustrates the lifting mechanism in its normal position, the driving element |45 is provided with a circular portion |63 which engages the circular hollow |64 of the driven element |48 for the purpose of locking the latter element in its initial position.

The cycle of the first Geneva stop mechanism, which is adapted to relax the spring 16, has been heretofore described, and from an inspection of Figs. 1D, 12 and 14, it will be seen that this first Geneva stop is synchronized with the second Geneva stop which is adapted to shift the fulcrum and lift the presser mechanism. Fig. 12 illustrates the lifting mechanism at that point in its cycle where the first Geneva stop has completely relaxed the spring 18 but the driver |45 of the second Geneva stop at this point has rotated from its initial position (shown in Fig. l0) to a position where its pin |46 is about to enter the slot |41 of driven element |46, thus to initiate movement in this latter element. It is to be understood, therefore, that no movement can be imparted to the element |46 until the spring 16 is relaxed completely.

Referring to Fig. l2, the spring is relaxed and, therefore, further movement of the chain 66 will be effective to: urge the pin |46 into slot |41 for the purpose of -driving the element |48 in a clockwise direction, to the end that its teeth |56' will urge the rock-bar forwardly and actuate the stubshaftV 84 as above described. During this portion of the cycle, it willbe noted that pin H9 works c lear of the slot |26 and thus the element will continue to turn without rotating'the element I2 I.

From the above description, it will be understood that a single downward movement of the chain |66 will producethree successive .actions within the lifting mechanism. The spring 18 `is first relaxed by the action of the first Geneva stop, the second Geneva then is activated to shift the rock-bar forwardly thus to raise the ulcrum point, and due to the existence of the arcuate slot |59, the lifting of the presser-bar 56 is delayed until the fulcrum is out of engagement with the lever 11.

Upon releasing the manually applied force exerted on the treadle chain |66, the above described mechanism will return to its normal position (shown in Fig. 10) under the force of a pair of tension springs |65 and |66 which are eective to retension the coil spring 16. At their upper ends, both springs |65 and |66 are secured to the frame |63 by means of a screw' |61, and at their lower ends they are secured to the upper portion of a flexible steel band |66 which is fixed, by means of a screw |69, to an eccentric hub |16 carried upon an end of the shaft II5. As stub-shaft I I5 also carries the gear I4, it will be understood that as the eccentric hub |16 is rotated in a clockwise direction it will place the springs |65 and |66 under increased tensionso that they will urge the shaft ||5 to rotate in an opposite direction when the force is removed from the chain |66. These springs are of sufficient strength to drive the entire mechanism back to its initial position as they act through the toggle links |29 and |36 which are designed to have suflicient mechanical advantage to overcome the force of the springs 1B. It is to be noted that the hub |16 is shaped in a manner such that the initialA movement thereof,vin a clockwise direction from the position shown in Fig. l0, will impart to the springs |65vv and |66 the majorportion of the increased 11 tension, and that the further movement of the hub will impart a lesser degree of tension to the springs. By means of this hub construction, no undue tension will be imparted to the springs.

The presser-bar and top feed-bar may be locked in their respective raised positions by means of a vertically disposed lock-pin mounted in a lug |1| provided on the machine head |9. This lock-pin device comprises a hollow stationary sleeve |12 fitted into the lug |1| and secured therein by means of a set screw |13. Slidingly mounted within the sleeve |12 is a cylindrical pin |14 having a slab-sided upper portion |15 which enters a corresponding slot |16 provided within the upper portion of the sleeve |12. This pin |14 is adapted to be raised manually against the force of a small coil spring |11 and then turned so that the slab-sided portion of the pin is out of phase relative to the slot |16, which latter action is effective to lock the pin in its raised position as shown in Fig. 5; As the pin is located beneath the top feed-lift lever 52 it is effective, in its raised position, to prevent the lever and consequently the presser-bar and top feed-'bar'from returning to their normal lowered position.

The present device, therefore, provides a means whereby the presser-bar and/or the top feeding mechanism of a sewing machine may readily be raised above the work with the expenditure of a minimum amount of energy by the operator.

Furthermore, this device enables the pressermechanism to be equipped with a spring of requisite strength, las the device provides for easily relaxing any spring'that may, with advantage, be applied to'a sewing'machine vpresser-mechanism.

Having thus set forth the nature of the invention', what I claim herein is: l

Y1. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a lever having one end portion thereof in operative engagement with said presser-bar, fulcrum means in engagement with an intermediate portion of said lever, a spring in engagement with the other end portion of said lever and being effective to bias said presser-bar toward said work-support,'means to removeitheY force of said spring from said presserbar, and means operable upon the uremoval of said spring force from said'presser-bar for shifting said presser-bar away from'said work-support.

2. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a vpresser-bar, a lever having one end portion thereof` in operative engagement with said presser-bar, fulcrum means in'engagement with an intermediate portion of said lever, a spring in engagement withthe other' end portion of said lever and beingeffective to bias said presser-bar Ytoward said work-support, and manually'operable means upon an initial movement of which the force 'of said spring is removed er-bar toward said work-support, means for removing the force ofr said spring from said presser-bar preparatory to shifting said presser-bar,

means for moving said fulcrum means out of en- 5/ gagement with said lever, and means for shift- Iing said presser-bar away from said work-support.

4. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a lever having one end portion thereof in operative engagement with said presser-bar, a fulcrum in engagement with an intermediate portion of said lever, a spring in enga-gement with the other end portion of said lever and being effective to bias said presser-bar toward said work-support, means for removing the force of said spring from said presser-bar preparatory to shifting said presser-bar, and means actuated by said rst mentioned means for 'shifting said presser-bar away from said work-support upon the removal of said spring force from said presser-bar.

5. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a lever having one end portion thereof in operative engagement with said presser-bar, a fulcrum in engagement with an intermediate portion of said lever, a spring in engagement with the other end portion of said lever and being effective to bias said presser-bar toward said work-support, means for moving said fulcrum out of engagement with said lever preparatory to shifting said presser-bar, and means actuated by said first mentioned means for shifting said presser-bar away from said Work-support.

6. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a4 spring for pressing said presser-bar toward said work-support, a manual control member, means including a toggle mechanism connected with said member for removing the force of said spring from said presser-bar, presser-bar lifting means connected with said member and being effective to shift said presserbar away from said work-support, and lost-motion mechanism associated with said member for forcing said toggle mechanism and said presserbar lifting means to be operated successively by a single continuous movement of said member.

'7. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a spring for pressing said presser-bar toward said work-support, a manual control member, spring-disengaging means connected with said member for removing the force of said spring from said presser-bar, presser-bar lifting means connected with said member and being effective to shift said presser-bar away from 'said work-support, and means including a Geneva stop mechanism associated with said member for timing the actions of said spring-disengaging means and said presser-bar lifting means so that they may be operated successively by a single continuous movement of said member. 8. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a spring for biasing said presser-bar toward said work-support, means interposed in operative relation between said spring and said presser-bar for multiplying the applied force of said spring and applying the resultant upon said presser-loana manual control member, springdisengaging means connected with. said member for removing the force of said spring from said presser-bar, presser-bar lifting means connected with said member and being effective to shift said presser-bar away from said work support, and means including a Geneva stop mechanism 'associated with said member for timing the actions of said spring-disengaging means and said presser-bar lifting means so that thei may be operated successively by a single continuous movement of said member.

9. A presser-mechanism for sewing machines having a frame including a wrk-support, comprising, a presser-bar, a spring for urging 'said presser-bar toward said Work-support, a manual control member, spring-disengaging means connected with said member Vfor removing the force of said spring from said presser-bar, presser-bar lifting means connected with said member and being adapted to shift said presser-bar away from said work-support, a rst Geneva stop mechanism interconnected between said member and said spring-disengaging means, a second Geneva stop mechanism interconnected between said member and said presser-bar lifting means, and means interconnected between said member and said rst and second Geneva stops for timing the actions of said spring-disengaging means and said presser-bar lifting means so that they may be successively operated by a `single lcontinuous movement of said member.

10. A presser-mechanism for sewing machines having a frame including a workesupport, a presser-bar, a spring for urging Vsaid pressenbar toward said work-support, means interposed in operative relation between said spring and said presser-bar for multiplying the applied force of said spring and applying the resultant upon said presser-bar, spring-disengaging means including a toggle mechanism effective to remove the force of said spring from said presser-bar, presser-bar lifting means effective to shift said presser-bar away from said Work-support, a pair of Geneva stop mechanisms, one of said Geneva stop mech anisms being associated in driving relation with said spring-disengaging means, the other Geneva stop being associated in driving relation with said presser-bar lifting means, and a manual control means connected to said Geneva stop mechanisms so as successively to actuate said spring-disengaging means and said presser-bar lifting means by a single continuous movement of said manual control means.

11. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-bar, a lever having 'one end portion thereof in operative engagement with said presser-bar, spring means in engagement With the other end portion of said lever and being effective to bias said presser-bar toward said work-support, fulcrum means in engagement with an intermediate portion of said lever, a manual control element, spring-disengaging means connected with `said control element for removing the force of said spring from said pressn er-ban fulcrum shifting means connected with said control element for shifting said fulcrum away from said lever, presser-bar lifting means connected with said control element for shifting said `presser-bar away from said work-support, and means associated with said control element for timing the actions of said last three mentioned means so that they will be successively operated by a single continuous movement of said control element,

12. In a sewing machine having a frame including a head and a work-support, the combination lof a rpresser-bar slidably mounted within saidV head, a :spring for pressing said presser-bar toward said work-support, means comprising ya lever of the first order interposed between said spring and vpresser-bar for imposing upon said spring a range of movement materially longer than that of said presser-bar, force-multiplying means for removing the pressure of said spring from said presser-bar, and manually controlled meansoperable upon removal of said :spring vpressure from said presser-bar for shifting said presser-bar away from .said work-support.

13. In a sewing machine, the combination of a plurality of work-engaging feet, a spring vfor pressing said feet upon the work, means interposed in operative relation between said spring and said feet for imposing upon said spring a range of movement Imaterially longer .than that of either of said feet, means for imparting mu tually alternating lifting movements to said feet against the `force of said spring, manually controlled means vincluding a force-multiplying mechanism for removing the pressure of said spring from said feet, and means actuated by said manually controlled means and operable upon removal of said spring pressure from said feet for shifting said feet away from said work-support.

14. .The combination in a sewing machine having a frame including .a work-support, a reciprocatory .presser-foot carrying bar, a feeding-foot carrying 'bar mounted for endwise reciprocatory and laterally jogging work-feeding movements, means for Vreciprocally actuating Vsaid bars in di rections :toward and from said work-support, a spring for biasing each of said bars toward said work-support, manually controlled means including a .force-multiplying mechanism for removing the pressure of said spring .from each of said bars, and means actuated by said manually controlled means and operable `upon the removal of said spring lpressure from said bars for shifting said bars away from said work-support.

15. In a sewing machine, the combination of a plurality of work-engaging feet, a swinging arm, a pivotal support for said arm, separate connections between said arm and said feet, `a lever having one end thereof connected with said arm, a spring connected to the other end of ysaid -lever so as to force said feet against the work, a fulcrum member cooperatively associated with said lever and in engagement therewith at a point adjacent the arm so as to provide lthe spring with a range of movement materially longer than that of either of said feet, means to shift said fulcrum member away from said lever, and means effective upon the removal of said fulcrum (from said lever to shift said feet away from the Work.

v16. A presser-mechanism adapted to be used with a machine of the class described having a presser-bar and a spring for biasing said presser-bar toward said work, said presser-mechanism comprising, a manual control memb'er, a first Geneva ,stop mechanism operatively connecting said manual rcontrol member with .said spring and being effective upon an initial movement of said control member to remove the force of said spring from said presser-bar, a second Geneva stop mechanism connecting said manual control member with said presser-bar and being effective upon the removal of said spring force from said presser-bar to raise said presser-bar off the work, and means associated with said control lever for sluiting said manual control member back into its initial position upon the release of all manual control therefrom.

17. A presser-mechanism adapted to be used with a machine of the class described having a presser-bar and a spring for biasing said presserbar toward said work, said presser-mechanism comprising, a manual control member, a first means operatively connecting said manual control member with said spring and being effective upon an initial movement of said control member to remove the force of said spring from said presser-bar, and a second means connecting said manual control member with said presser-bar and being effective upon the removal of said spring force from said presser-bar to raise said presser-bar oif the work; said first and second means each comprising, a driving element, a driven element, a pin member carried by said driving element, and a complemental member carried by said driven element coacting with said pin and shaped to permit said pin member to impart a driving impulse to said driven member succeeded in one of said means and preceded in the other of said means by a dwell.

18. In a sewing machine, the combination of a presser-bar, a spring to bias said presser-bar toward the work, a manual control member, force-multiplying means connected with said control member and being effective to remove the force of said spring from said presser-bar upon an initial movement of said control member, presser-bar lifting means connected with said presser-bar and being effective to shift said presser-bar away from the work upon the removal of the spring force from said presser-bar, means associated with'said control member for shifting the latter into its initial position upon the release of all manual control therefrom, and a pair of timing devices, one of said devices being positioned between said control member and said force-multiplying means, the other of said devices being positioned between said control member and said presser-bar lifting means, said pair of timing devices each comprising, a driving element, a driven element, a pin member carried by said driving element, and a complemental member carried by said driven element coacting with said pin and shaped to permit said pin member to impart a driving impulse to said driven member succeeded in one of said devices and preceded in the other of said devices by a dwell.

19. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-member, a lever disposed in operative engagement with said presser-member, fulcrum-means in engagement with said lever, an arm sustained by said frame, a spring interposed between said arm and said lever for biasing said presser-member toward said work-support, means for causing relative movement between said lever and arm to relax said spring preparatory to shifting said presser-member, means for moving said fulcrum-means out of engagement with said lever, and means for shifting said presser-member away from said worksupport.

20. A presser-mechanism for sewing machines having a frame including a work-support, comprising, a presser-member, a relatively rigid lever disposed in operative engagement with said presser-member, a shiftable fulcrum having an operative position in engagement with said lever and an inoperative position out of engagement with said lever, a spring connected to said lever for normally biasing said presser-member toward said work-support, means for shifting said fulcrum from its operative position to its inoperative position preparatory to raising said pressermember, and means for raising said pressermember from said work-support.

21. A presser-mechanism for sewing machines having a frame provided with a work-support, including, a presser-member, a lever disposed in operative engagement with said presser-member, a shiftable fulcrum having an operative position in engagement with said lever and an inoperative position out of engagement with said lever, a spring connected to said lever for normally biasing said presser-member toward said work-support, means for moving said fulcrum into and out of its operative position, and means rendered effective by the movement of said fulcrum for lowering and raising said presser-member relative to said work-support.

22. A presser-mechanism for sewing machines having a frame provided with a work-support, including, a presser-member, a lever disposed in operative engagement with said presser-member, a fulcrum-element turnable about an axis into and out of operative position with said lever, a spring connected to said lever for normally biasing said presser-member toward said work-support, manually controlled means for turning said fulcrum-element into and out of its operative position and an arm operatively associated with said presser-member and connected t0 said fulcrum-element so that the turning of said fulcrum-element into and out of its operative position elfects a lowering and raising of said presser-member relative to said work-support.

23. A presser-mechanism for sewing machines having a frame provided with a work-support, comprising, a presser-member, a lever disposed in operative engagement with said pressermember, a fulcrum-element turnable about an axis into and out of operative position with said lever, an arm sustained by said frame, a spring interposed between said arm and said lever for biasing said presser-member toward said worksupport, rst means for effecting relative movement between said lever and said arm to remove the force of said spring from said presser-member, second means operated automatically by and in series with said first means for turning said fulcrum-element out of its operative position, and third means rendered effective by the turning movement of said fulcrum-element for raising said presser-member from said work-support.

FREDERICK F. ZEIER.

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

UNITED STATES PATENTS Number Name Date 1,265,986 Ashworth May 14, 1918 1,279,112 Horton Sept. 17, 1918