US2386840A - Presser bar vibrating device for darning - Google Patents

Description

Oct 1945. c. E. COLEGROVE 2,386,840

PRES-5BR BAR VIBRATING DEVICE FOR DARNING I Filed May 18,1944 2 Sheets-Sheet 1 V 55 INVENTOR. gy/W155i Cara/vow aw Maw 25/ 1945. c. COLEGROVE 2,386,840

PRESSER BAR VIBRATING DEVICE FOR DARNING Filed May l8, 1944 2 Sheets-Sheet 2 F 6 INVENTOR.

CHAR/.55 2 Coma/ears M Ma M I firTae/vsys Patented Oct. 16, 1945 PRESSERBAR VIBRATIN G DEVICE FOR DARNING Charles E. Golegrove, Lakewood, Ohio, assignor to Sears, Roebuck and Company, Chicago, 111., a corporation of New York Application May 18, 1944, Serial No. 536,066

7 Claims.

This invention relates to asewing machine and more particularly toanarrangement whereby the presser bar and presser foot thereof can beadapted for ordinary sewing operations'or for darning operations.

The invention may be used in sewing machines of the general type of that shown-in the Hohmann et a1. Patent No. 2,247,379, July' 1, 1941. A sewing machine of this type is convertible from a condition wherein the machine is adapted for plain sewing to one wherein it isadapted for darning. This type of sewing machine employs a fiat work bed for ordinary sewing operations and a cylindrical arm which supports the work when the machine is used for darning.

An object of the invention is to provide in a sewing machine a presser bar mechanism which can be adapted readily for-either ordinary sewing operations or for darning operations, and which mechainsm is simple in construction and eflicient in operation.

Another object of the invention is to provide in a presser bar mechanism an actuating means for the presser bar and which means can be adjustcd readily and easily to or from a position for ordinary sewing operations-wherein it is in active or from or to a plurality of active positions for darning operations and wherein end wise vibrating strokes of the desired amplitude may be imparted to the presser bar, in accordance with the thickness of the material being darned.

Further and additionalobjects and advantages of the invention will become apparent during the detailed descriptions of several embodiments thereof which are to follow.

Referring to the'accompanying drawings,

Fig. 1 is an end elevational view looking at the free end of the horizontal portion of an arm bracket of a sewing machine and in which is employed apresser bar mechanism embodying the present invention, the actuating means for the presser bar being shown in inactive position.

Fig. 2 is a View partly in section and partly in elevation, with the section taken substantially on line 2-2 of Fig. 1 looking in the direction of the arrows, while the elevation is taken looking from the right of Fig. 1.

Fig. 3 is a fragmentary View simliar to Fig; 1 but showing the actuating means for the presser bar adjusted to an active position and wherein it imparts lift to the presser bar between successive strokes of the needle bar.

Fig. 4 is a fragmentary view similar to Fig. 1 but shows a modified form of presser'bar mechanismembodying the invention from that shown in Figs. 1 to 3 inclusive.

Fig. 5 is a fragmentary view similar toFig. 4 but shows the actuating means for the presser bar of Fig. 4 adjusted to an active position wherein it imparts lifting movement to the presser bar between successivestrokes-of the needle bar, and

Fig. 6 is a sectionalview taken substantiallyon line 66 of Fig. 5 looking in the direction of the arrows. Q r

Referring to Figs. 1 and 2, the work plat'eb'r work bed of the sewing machine is indicated at l0 and said plate or bed'is used for ordinary sewing operations. When the machine is used for darning operations the plate orwork bed 10 is removed and a cylinder arm H is employed to support the work as is well understood in the art and as is clearly disclosed in said Hohmann et a1. Patent No. 2,247,379.

The horizontal portion of the sewing machine arm bracket is indicated at I? and said portion rotatably supports the main or'needleb'ar shaft 13 which may be driven by any suitable means well understood in the sewing machine art and forming no part of the present invention. The free end of the horizontal portion I2 ofnthese'wing machine arm bracket reciprocatingly supports the vertically disposed needle bar M, as is common in the art, and said needle bar has detachably connected to its lower end, in the usualway; a

needle l5. p y

The needle bar [4 is operatively connected to the needle bar shaft l3 by means of a pivoted. link l6 which is pivotally connected to a crank arm IT, in turn, pivoted to a crank disk l8 fixed to the end of the needle bar shaft I3, as is well understood in the art. The usual tensiondevijce l9 and the customary take-up mechanism 20 are provided onthe free end. of the horizontal portion 12 of the arm bracket but form no. part of the present invention. It will be understood that as the needle bar shaft l3 rotates, reciprocating movement will be imparted to the needle bar I4 and the needle l5 carried thereby, to cause the latter to pass through and out of the work during the sewing operation. l

The free end of the horizontal, portion l2 of the arm bracket also slidably supports the verti cally disposed presser bar 21 which, at its lower end, carries a presser foot 22 which engages the work and is provided with a slot through which the needle l5 passes as it reciprocates. The presser bar 2| and presser foot 22 are held, normally in their downward position under spring tension by means of a coil spring 23 which surrounds the presser bar and has its upper end abutting against a threaded adjusting nut 24 whereby the tension of the spring can be varied. The lower end of the coil spring 23 abuts the upper side of a presser bar block 25 that is secured to the presser bar and extends into a slot formed in the arm bracket. A pivoted cam lever 26 is carried by the arm bracket and said lever'can be moved from its lower inactive position as shown in Fig. 1 to its upper active position wherein it has engaged the block 25 to raise and hold the latter and the presser bar 2| and presser foot 22 upwardly against the action of the spring 23. The structure so far described is well known and will be fully understood by those skilled in" the art.

As already stated, in ordinary sewing opera-- shown in Fig. 1, wherefore the bell crank lever is maintained in its proper inactive position by the positive engagement of the projection 29a with the shoulder. The free or'outer end of the arm 29 of the bell crank lever is provided on its upper side with an upwardly extending rounded projection 292) which when the bell crank lever is in'inactive position as shown in Fig.1 is spaced below thelower edge of the block 25 when the latter is in its lowermost position.

It will be noted that when the shaft 3| is rocked in a counterclockwise direction as viewed in Fig. 1, the pivotal axis for the bell crank lever tions the presser foot 22 is held engaged with the 1 I work under tension of the spring 23 during the entire sewing operation. However, when the sewing machine is used'for darning and similar operations it is necessary to impart a lifting movement to the presser foot between successive needle strokes in order that the work can be shifted on its support.- The amplitude of theupward lifting movements imparted to the presser foot and presser bar will be varied in accordance with the thickness of the workupon which the darning operations are being performed. As for example, if thin socks or stockings are being darned, only a, slight upward lifting movement need be given to'the presser foot and presser bar, while on the other hand if the darning operations are taking place on blankets or other thick material a much greater upward lifting movement must be imparted to the presser foot22 and the presser bar, The present invention is directed to an improved actuatingmeans for imparting the upward lift movements to the presser bar and presser foot for daming operations. This actuating means can be adjusted to an inactive position for normal sewing operations or it can beadjusted to any one of a number of active positions for darning operations; the particular adjustment to active position which is given to theac- A tuatingmeans depending upon the thickness of the material. to be operated on and the desired or. necessary amplitude of the upward lifting movement required for the presser foot and the presserban The needle bar It is provided with a roller 21. which when the actuating means for the presser baris in inactive position performs no function. The actuating means for the presser bar which cooperates withthe roller 21 when said means is adjusted to an active position, comprisesin this instance a bell crank lever formedof the up-. wardly. extending arm 28 and. the. substantially horizontally extending arm 29. The said bell crank lever is pivoted-at the junction of the arms 28 and 29 on aneccentric pin 3|] carried by one endof a shaft 3| that is rockablymounted in the horizontal portion of the arm bracket and extends therethrough at rightangles to the needle bar H. The upper end of the arm 28 of .the bell crank lever is provided with a curved surface 28a which whenthe bell crank is in the inactive position shown in Fig. 1 does not contact with the roller 21 .carried. by the needle bar during the re-, ciprocationrof said bar. The outer or-free end ofthe substantially horizontal arm 29 of the. bell crank lever. is provided. on its under side with a rounded downwardly extending projection 29a. that engages a shoulder of the arm bracket when.

the bell cranklever is' in the inactive position is raised and shifted toward the left as viewed in Fig. -'1 and that such raising and shifting of the pivotal axis of the lever moves the curved portion 28a-of the arm 28 thereof into the path of movement'of the roller 21 carried by the needle bar as said roller travels with the needle bar from its lowermost position to its uppermost position as shown in Fig. 3. It will be apparent that when the curved surface 28a of the arm 28 of the bell crank lever is contacted by the roller 21 during upward movement of the needle bar I 4 said roller will move the arm 28 and rock the bell crank lever in a clockwise direction about its pivot, with the result that the arm 29 will swing upwardly causing the upward projection 29b thereof to engage the block 25 and raise the presser bar 2| and presser foot 22 against the action-of the spring 23. The amplitude of the rocking movementimparted to the bell crank lever by the upward movement of the roller '21. depends upon the adjusted position of the pivotal axis of said lever and can vary between a minimum rocking movement and a maximum rocking movement. Of course the amplitude of the rocking movement imparted to the bell crank lever determines the amplitude of the upward lift movement imparted to the presser bar 2| and the presser foot 22 and should be correlated to the thickness of the material upon which the darning operation is taking place.

The shaft 3| is rocked'from the position wherein the bell crank lever-is inactive to a position wherein the bell crank lever is active by means of an operating handle 32 fixed to the right hand end of the shaft 3| as viewed in Fig. 2. Various suitable means'may be employed for holding the shaft 3| and the handle 32 in any position to which they have been rocked and in the present illustration there is shown for this purpose a bowed spring 33 interposed between the handle 32 and the arm bracket. In Fig. 1 the handle 32 is shown as extending substantially horizontal when the bell crank lever is in inactive position, while in Fig. 3 the handle 32 is shown as having been moved from the inactive horizontal positionto an active downwardly inclined position.

Referring more specifically to Fig. 3, it will be observed that the'roller 21 is in engagement with the curved surface 28a of the arm 28 of the bell crank leveras itmoves upwardly-with the needle bar and that such engagement will rock the bell crank lever in a clockwise direction to cause the projection 29b of the arm 29 thereof to press upwardly on the block 25 and lift the presser bar against the action of the spring 23. When the needle bar It moves downwardly the spring 23 will force the presser bar downwardly and will rock the bell crank lever in an anticlockwise direction as viewed in Fig. 3. Hence, it will be seen that each time theneedle bar l4 and needle I 5 are moved upwardly the bell crank lever is rocked and the presser bar 2| and presser foot 22 elevated, at which time the work may be shifted. It will also be seen that the ampli tude of the lifting movement imparted to the presser bar and presser foot may be varied in accordance with the shifting adjustment imparted to the eccentric pin 30 by the rockingof the shaft 3| and handle 32.

From the foregoing description it will be evident that a simple and accurate actuating means is provided for the presser bar whereby during normal sewing operations said means can be rendered inactive while for darning operations the same means can be adjusted to any one of a number of different active positions correlated to the thickness of the material upon which the operation is being performed. The arrangement for effecting these adjustments of the actuating means possesses the advantageous attribute of simplicity as compared to the more or less complicated arrangements heretofore used for this purpose.

In Figs. 4 to 6 inclusive there is illustrated'a modified form of actuating means for-the presser bar 2| which differs somewhat from the form previously described. In this modified form the needle bar I4, presser bar 2|; presser bar block 25, spring 23 and roller 21 on the needle bar, are identified by the same reference characters as in the previously described form, inasmuch as they are substantially identical therewith. The adjusting shaft 34 for the actuating means in this modified form is rock-ably supported in the arm bracket I2 in a manner similar to the adjusting shaft 31 of the first described form.

The shaft 34 adjacent its left hand end, as viewed in Fig. 6, has an arm 35 freely rockably supported on the shaft concentrically to the shaft axis and there is secured to the arm 35 a lever arm 35 which has its inner side curved as indicated at 36a for cooperation with the roller 21 as will later be explained. The arm 35 and the lever arm 36 could be formed of a single piece of material, but for purposes of assembly and to simplify the manufacture thereof the same are shown as formed of separate pieces which are suitably secured together. A coil spring 31 abuts against the outer or right hand side of the arms 35 and 36 and against the interior of the arm bracket 12; said spring being supported in proper position by a pin 38 and acting at all times to urge the arms 35 and 38 toward the roller 21.

The left hand end of the shaft 34 is provided with an eccentric pin 39 on which is rockably mounted a lever arm 40, the free end of which is provided on its upper side with a curved'protuberance 48a adapted to engage the presser bar block 25 when the actuating mechanism is in its active adjusted position. The lower edge of the lever arm 40 is provided with a surface portion 491) that engages the interior surface of the arm bracket l2 when the actuating means is in inactive position. A link 4l has its opposite ends pivotally connected respectively to the lever arm 36 and the lever arm 40. An adjusting handle 42 is secured to the right hand end of the adengagement-with the interior surface of the arm bracket l2 and the link 4| has been moved by the lever arm 40 to move the lever arm 36- to the position shown in Fig. ,4 and hold the latter therein, at which time the upward travel of the roller 21 with the needle bar 14 will not impart any appreciable. movement to the lever arm 36. When the handle 42 is moved from the position shown in Fig. 4 toward the position shown in Fig. 5 the eccentric pin 39-moves as the shaft 34 is rocked and shifts the lever arm 40 toward the left as viewed in the drawings, and'such shifting movement of. the lever arm 40 acts through the link. to drawn or pull the lever arm 36 toward the needle bar l4 and more fully into the path of the roller 21. Therefore the roller 21 as the needle bar moves upwardly acts on the surface 36a of the lever arm 36. and rocks said arm to. the right a substantial distance withthe result that the link 41 pulls upwardly on the lever arm 40 and causes the curved protuberance 40a thereof to engage with. and lift the block 25 againstthe action of the spring 23 with a resultant lifting of the presser bar and presser foot.

Fromthe foregoing description it will be seen that the actuatingmeans in this modified form can be rendered inactive when the machine is performing ordinary sewing operations but by simple movement of the lever 42 can be ren dered active for lifting the presser bar on each up stroke of the needle bar and therefore the machine can be used for darning operations. It will also be noted that a'range of active adjustments can be imparted tothe actuatin mechanism wherefore the amplitude of lift given to thepresser bar can be varied in accordance with the thickness of the material upon which the darning operation is being performed.

Although several preferred embodiments of the invention have been illustrated and described herein it should be understood that the invention is susceptible-of various modifications and adaptations within the scope of the appended claims.

Having thus described my invention I claim:

1. In a sewing machine adapted to function selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar, a presser bar normally spring pressed in a downward direction, a member mounted for rocking movement on a shiftable' axis, means for shifting said axis selectively to either one of two positions, and means forming an operative association between said member and said needle bar and between said member and said presser bar only when said axis is shifted to one of said two positions.

2. In a sewing machine adapted to function selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar having thereon an actuating element, a presser bar normally spring urged in a downward direction and having thereon an abutment portion, a lever arm mounted for rocking movement on a shiftable axis and having at its free end a. portion adapted to engage said abutment portion when said lever arm is rocked upwardly, means for shifting said axis selectively to either one of two positions, and means effective only when said axis is in one of said two positions for operatively associating said lever arm with said actuating element wherefore upward movement of said needle bar efiects upward rocking movement of said lever arm and in turn upward movement of said presser bar.

3. In a sewing machine adapted to function selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar having thereon an actuating element, a presser bar normally spring urged in a downward direction and having thereon a lifting block, a member mounted for rocking movement'on a shiftabl axis and having a portion adapted when said member is rocked upwardly to engage said block and lift said presser bar, a lever arm operatively connected with said member and having an.- upwardly extending portion provided with an actuating surface adapted to cooperate with said element during reciprocation of said needle bar to rock said arm and member, and means for shifting saidaxis of said member to dispose said lever arm and the actuating surface thereof in either an inactive position relative to said 'element Or in an active position relative thereto. 4. In a sewing machine adapted to function selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar having mounted thereon an actuating element, a-presser barinormally spring urged in a downward direction and having thereon a lifting block, a rockable shaft having an eccentric portion, a lever mounted on said portion for rocking movement and having its free end underlying said lifting block on said presser bar, a lever arm operatively connected to said lever and having its upper end located adjacent to said actuating element, and means for rocking said shaft to shift said eccentric portion and the axis of rocking movement of said lever and to move said lever arm either to a position wherein said actuating element acts on said arm during upward movement of the needle bar to rock said arm and said lever or to aposition wherein said element is inactive with respect to said lever arm.

5. In a sewing machine adapted tofunction selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar having mounted thereon an actuating element, a presser bar normally spring urged in'a downward direction and having thereon a lifting block, a rockable shaft having an eccentric portion, a lever mounted on said portion for rocking movement and having its free end underlying said lifting block on said presser bar, a lever arm operatively connected to said lever and having its upper end located adjacent to said actuating element, and means for rocking said shaft to shift said eccentric portion and the axis of rocking movement of said lever and to move said lever arm either to a position wherein said actuating element acts on said arm during upward movement of the needle bar to rock said arm and said 'lever and raise said block and presser bar or to a position wherein said element is inactive with respect to said lever arm, and means for holding said shaft in any position to which it is rocked.

6. In a sewing machine adapted to function selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar provided with' a roller, a presser bar normally spring urged in a downward direction and provided. with a lifting block, a rockable shaft extending transversely to said needle bar and presser bar and provided with an eccentric'portion, a bell crank lever mounted on said eccentric portion atthe junction of its angularly disposed arms, one of said arms being provided at its free end with means adapted to engage said lifting block of said presser bar, the other of said arms being provided adjacent its free end with an actuating surface adapted to cooperate with said roller during reciprocation of said needle bar, an actu ating member for rocking said shaft to shift said eccentric portion and the axis of said bell crank lever to a position wherein said roller is inactive with respect to said actuating surface or to a position wherein said roller contacts said actuatingsurface and rocks said lever during upward movement of said needle bar to cause the first named arm of the lever to engage said lifting block and raise said presser bar.

'7. In a sewing machine adapted to function selectively for ordinary sewing operations or for darning operations, a reciprocating needle bar having thereon a roller, a presser bar normally spring urged in a downward direction and having thereon a lifting block, a rockabl shaft extending transversely to said needle bar and having an eccentric portion, a lever mounted on said eccentric portion and having its free end underlying said lifting block, an upwardly extending lever arm rockably mounted on said shaft concentrically therewith and having at its end an actuating surface located adjacent to said roller, a link pivotally connected to said lever and said lever arm, and means for rocking said shaft to shift said eccentric portion and the axis of rocking movement of said lever to swing said lever arm through said link into a position where the actuating surface thereof will lie in the path of movement of said roller whereby said lever arm, linkand lever will be rocked by said roller during upward movement of said needle bar to cause said lever to engage said lifting block and raise the presser bar or to a position wherein said roller is inactive with respect to said actuating surface of the lever arm.

CHARLES E. COLEGROVE.

Images