US2544029A - Presser foot control apparatus - Google Patents

Description

March 6, 1951 T. KOTZIN ET AL 2,544,029

PRESSER FOOT CONTROL APPARATUS Filed Sept. 10, 1945 3 Sheets-Sheet 1 lNVEN'TOR-S Tab/a5 Mary/r7 March 6, 1951 T. KOTZIN ET AL PRESSER FOOT CONTROL APPARATUS 3 Sheets-Sheet 2 Filed Sept. 10, 1945 INV ENTORS Tab/10$ Kay/'17 Jerome C. ey BY ATTORN EY March 1951 T. KOTZIN ET AL 2,544,029

PRESSER FOOT CONTROL APPARATUS Filed Sept. 10, 1945 3 Sheets-Sheet 5 /Eg- 4 23-4 a 23 is 73-6 s [N v E N- TO 25 75/os Aozfgm Jerome C. lz/d'y Y ATTORN EY :minute. spee hitis essential to reduce, inas great a de- Patented Mar. 6, 1951 .Tobias Kotz in, Los Angeles, and Jerome Whittier, Calif.

C. Ivey,

Application September 10, 1945, Serial No. 615,279

This invention relates to sewing machines;

more particularly, it relates to apparatus for controlling the presser foot of such machines.

Sewing machines are common y provided with mechanism for advancing the work in synchronism with the movements of the needle bar and needle to form stitches. Such mechanism usually includes a feed dog and a spring-urged presser foot for resiliently maintaining, the work against the feed dog to be advanced by movement thereof. Means also are provided for lifting the presser foot to free the work from the feed dog to allow removal or adjustment of the work, as ell as to facilitate insertion of a new work piece. i l

- In a conventional arrangement, the presser foot is either urged toward the feed dog with substantially :the entire pressure of which it is capable, or else it is lifted clear of the work and .feed dog. With such an arrangement, when the presser foot is raised to manipulate the work, as,

for example, to turn the work at an abrupt angle, the work is loose between the presser foot and .the supporting table or throat pla e; accordingly, it is apt to follow the needle in its up-anddown movement, and thereby an undesirable condition exists. Further, if the machine happens "to stop with the needle out of the work, the work is entirely unrestrained when the presser foot is lifted. Since it is desirable to swing the work about a fixed point, such as a needle, the adjustment of the work for a sucxceeding operation is rendered more diflicult.

In performing certain operations, it is desirable partly to reduce the pressure of. the presser standing the action of the feed dog. Ahighly skilled operator may be able to accomplish this ,by means of the mechanism usually provided for lifting the presser foot, thepresser foot be- .ing lifted slightlyand maintained at exactly the right distance above the throat plate to permit the performing of various operations, such, for

example, as back staying, darning, embroidering.

9 clams. (01. 112236) foot to permit the operator to control and change I the advancing movement of the work, notwith- In gentral, however, such control ofthe presser footis, very diiiicult to accomplish, since the raising and lowering of r the presser foot disturb .certain thread take-up and other control devices associated-with the thr ad. v H

Modern commercial sewing machines operate ata rate of 4,000 to 5,000 or more stitches per To take full advantage of such high in detail, illustrating the general principles of the invention; but it 'is to be understood that this gree as is possible, the

thickness. .vention toprovide means whereby the presser foot may be optionally caused to exert increased pressure. v i

While it is of course commonto provide adlift the foot from the work.

time required for manipulating the workbetween successive stitching operations. It is an important object of this invention to-provide means whereby the pressure exerted by the presser foot may be partly'reduced in a convenient manner to faciiltate manipulation of the work.

, ,It is another object of this invention to providemeans whereby the usual mechanism for lifting-the presser foot serves optionally to reducethe pressure of the foot, or to lift it clear of the work. It may be desirable to increase the pressure exerted by the presser foot above that suitable for normal operation of the machine under certain conditions as, for example, when encountering a portion of the work of unusual It is thus another object of this injusting means to alter the pressure exerted by a presser foot, such adjustment is within comparatively narrow limits, and is not adapted to be altered as an incident to operation of the machine, or while the machine is in motion. It is thus another object of this invention to provide means whereby the pressure of the presser foot may be readily altered as required in the normal operation of the machine.

It is still another object of this invention to provide control apparatus for a presser foot capable of exerting a normal pressure on the work which is optionally operable to reduce such normal pressure, toincrease such It is a still further object of this invention to provide, in connection with a presser foot having primary means operative to cause said foot to exert pressure on .the work, means for optionally rendering secondary means to become operative in place of said primary means, to cause the pressure foot to exert a reduced pressure.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of oneembodiment of the invention. For this purpose there is shown a form in the drawing accompanying and forming part of the present specification]-}The--fo'rm will' now be described detailed. description is not to be taken in a limit- ,ingsense, since the scope of this invention is Petd n dlW he pende e m pressure or to seen from the left of Fig. l, and partly in section taken as indicated by line 4-4 of Fig. 1; and

Fig. 5 is a detail section taken as indicated by line 55 on Fig. 4. Referring to the drawings, the control apparatus of the invention is shown as applied to a type of sewing machine which is in extensive use; but it is to be understood that the apparatusis equally applicable upon appropriate modification to other types of machines, and without departing from the spirit of the invention. In order to simplify the drawings, only the presser'foot and those parts relating to the control thereof are shown.

Referring particularly to Figs. 1 and 4, the

presser foot is indicated by the numeral I and in a well understood manner serves to releas ably and resiliently maintain the work 2 against the feed dog 3 (see Fig. 4) which advances the work from right to left as viewed in Fig.4 in an intermittent manner in accordance with the movements of the needle 4 and the needle bar 5.

The needle operates to form stitches in the work in cooperation with a bobbin and thread" (not shown) The presser foot is carriedby a presser bar 6. uid d for vertical movement in a sleeve or (bushing secured in the free end}; of the hori- .gontally extending hollow machine arm 9. The

arm 9 has a vertical columnar extension I0 at the other end which supports the arm above the' bed II (see also Fig. 2).

This bed is tiltably mounted in a conventional manner in a suitable opening |2 provided by a table I3. A drip pan I4 is provided below the opening |2. The presser "bar 6 is additionally guided by a guide member (see also Fig. 5) secured to the presser bar near the upper end thereof and siidably engaging a slot I6 formed in the end 8 of the arm 9.

A leaf spring IT is provided for continuously exerting a pressure urging the presser foot I downwardly and is mounted in the arm 9 (see Fig. 1). One end of the spring I1 engages the upper end of the presser bar 6 (see also Figs. 4

and 5) the other end being supported-on a member l3 extending transversely of the armi9 (see F g, A l a j sting screw I 9 threaded inwar ly from th pper side of arm 9 n ges the spring I! intermediate its ends and serves by ap propriate adjustment to urge the spring dow-n wardly against its supports, thus urging the;

-pr sse f ot downward y again ework 2.

This provides the primary force exerted by the presser foot, and may be altered by adjustment bf the screw I9 to suit the character of the work.

lifting bracket 2| (Figs. 4 and 5) is slidably mounted on the bushing] just below the guide :rnember l5. A spring cushioning member 22, which'may be a spring Washer; is int rpos tween the bracket 2| and. the guide I5 (see Fig.

14.);- A lifter 23 is accommodated in he slot It and is pivotally moun d. n th e d po o v the arm 9 by a pin 24. The lifter 23 has a cam face 23a adapted-to engage the lower edge of bracket 2| upon clockwise rotation of the lifter from the position shown: Continued-rotation of the lifter 23 raises the bracket 2| on the bushing I until the cushioning member 22 engages the guide member I5, whereupon further movement of the lifter 23 will raise the presser bar 6 and the foot I against the force of spring IT.

The cam face 23-a is so formed that a 90 rotation of the lifter 23 imparts sumcient movement to raise the presser foot I clear of the work 2 and to releasably retain the presser foot I and the lifter 23 in this position. When it is desired to return the presser foot I to engage the work 2, the lifter 23 is rotated counterclockwise to its original position.

The lifter 23 has an extension 23-h adapted to be gripped by the operator for lifting the presser foot. While it is apparent that it might be possible to hold the lifter 23 in such position as to merely reduce the pressure of the presser foot I on the work 2, it is not well adapted for isuchlpurpose, and such operation would require considerable deftness on the part of the operator. Further, the use of the lifter 23 in this manner is not desirable, since it leaves the operator with but one hand free to adjust the work.

Accordingly, additional means are provided for controlling the presser foot I, which may be actuated by the operator's knee, leaving both hands free. For this purpose, a rock shaft 2'! is provided extending lengthwise of the arm 9 and supported by suitable bearings therein. A crank 2B is provided on that end of shaft '21 adjacent the presser foot I and is connected to the lift bracket 2| by a link 29, pivoted at its opposite ends to the crank 28 and to the bracket 2| respectively (see Fi s. .1, 4 and 5). v

A second crank 30 is secured to shaft 21 near its opposite end (see Figs. 1 and 2) andis'provided with an eye 30-a for slidingly accommodating a lifting rod 3|. The rod 3| is provided with an adjustable abutment 32, the upper face 32a of which is adapted to engage the crank 3|], whereby upward movement of the lifting 'rod 3| imparts angular movement to the rock shaft The abutment 32 may conveniently comprise a set collar, secured on the rod 3| by'a set screw 33.

A bracket 34 (Figs. 1 and 2) is secured to the under surface of the'table |3 adjacent the extension II] of arm 3, and plvotally supports a rock lever 35 by means of a pin 36. The rock lever 35 has a downward extension 31 to which is adjustably secured the knee plate 38' as. well as a rearward extension 39 adjustably carrying a rod 4|]. The rod 40 has an arm 4| secured near its upper end having a hole 4|--a for accommodating a right angle extension 3|a formed on rod 3|. 1

The arrangement is such that with the parts in the relative positions shown, the presser foot I is urged downwardly with the primaryfo'rce imparted by the spring I'I. Movement of the knee plate 38 to the right, as viewed in Fig. 1, as by appropriate pressure of the operators' knee, will lift the lifting rod 3 I, imparting angular'motion to. the rock shaft 2'! in a clockwise direction "as seen in Fig. 2, and counter-clockwise as seen in Fig. s. This motion will cause the lift bracket 2| to be raised, which in'turn will raise the guide member I5 and lift the'presser foot I against the force of the spring I1. Release of the pressure on the knee plate '38, will permit the parts-to resume their initial positions. In this waythe 75 pressure of the presser foot may-berendered -effective or not, and at the same time both of the operator's hands are free. If it is desired to maintain the presser foot free of the work 2 for an appreciable interval, the lifter 23 may be operated to lock the foot in its position free of the work. Mechanism capable of this mode of operation is in general well known.

As previously discussed, it is often desirable to maintain the presser foot I against the work 2, but with a reduced pressure. While it mi ht be possible, at least in theory, to accomplish this by appropriate manipulation of the knee pad 38, such is not in general, a practical mode of operation. I

To provide for such reduction of pressure in a practical way and without requiring exceptional skill on the part of the operator, means are provided whereby the presser foot I maybe caused optionally to exert a secondary pressure "or force on the work upon removal ofthe primary force. For this purpose, the foot member 450i the presser foot I is joined to the presser bar 6 through a lost motion connection, and a'second spring means is provided which becomes eifec tive during part of the lifting operation of the presser foot to remove the primary force.

Thus as shown in Fig. 5 the presser bar 6 comprises a hollow member 46 having a bore 4 a closed at its upper end. The foot member 45 is secured in a conventional manner to ashank 41' having a reduced portion 4|--a providing an up wardly directed shoulder 4'|b. The reduced portion 4|--a is slidingly accommodated in the bore 46- 11. The shoulder '4 by engagement with the end of member 46 limits 3 downward movement of the member 46 with respect to the shank 41. A screw 48 having a head 48--a is threaded into the reduced shank 41-11, a slot 49being provided in the member 46 for the head 48-41. The screw head 48--a by engagement with the lower end of the slot 49 limits upward movement of the member 46 with respect to the shank 41. The slot 49 and screw 48 cooperate with the shoulder 4|-b and the end of the member 46 to form a lost motion connection between memb r 46 and shank'4'l. A light compression spring 5|] is confined within the member 46 between the upper end of the bore 46a and the top of the reduced shank 4L-a, urging shank 4'! downwardly in member 46. 4 I

In normal operation, spring overcomes spring 50, ,and hollow member 46 is urgedagainst shoulder 41 b. The entire pr sser-foot assembly is thus substantially unyielding in the direc tion of the Work. This condition is illustrated in Fig. 5. Therefore, when no lifting force is applied to the presser bar 6, the foot member 45 engagesthe work 2 and the hollow member 46 is urged downwardly tothe limit of movement with respect to shank 41 by the;,' 1sprin'g .11, the pressure of the spring I! thus being effective to urge the foot member 45 against the work 2. If now the lifting bracket 2| be operated by link 29 to lift the member 46 slightly, the force of the spring I1 will be entirely supported by member 46 and the bracket 2|, while only the force exerted by spring 59 urges the foot member 45 aaginstgthe work 2. This maybetermed conveniently,the secondary force Continued upward movement of the member46 will cause engagement of screw head 48-a with the lower end of slot 49, further upward movement of the member 46 thereafter lifting the foot member 45 clear of the work.

There is considerable movement of the memiber 46 after removal of the pressure of the spring l1, during which the pressure of the spring 5|) acts, and before the foot 45 is raised, provided by the previously described lost motion connection.

There is thus no critical movement required to cause the presser foot to exert only the secondary force on the work 2. Hence there is a considerable range of movement of the knee plate 38 after the primary force has been removed and before the presser foot I is lifted, and no skill isrequired of the operator.

' Means are also provided whereby the primary force acting on the resser foot may be temporarily. increased as desired by the operator. For this purpose a supplemental knee plate 5| (Figs. 1 and2) may beprovided which is ar-. ranged toiincrease the pressure exerted by the presser foot upon movement in a direction 019- posite to the movement-of knee plate 38 to decrease such pressure. As shown in Fig. 1, the knee plate 5| conveniently may be so arranged with respect to the knee plate 38 to provide a space for the operators'knee between them so that movement in one direction from a normal or neutral position serves optionally to decrease the pressure of the foot or to lift it from the work, and in the opposite direction to increase such pressure.

Furthermore, it is desirable to use for this purpose as much of the previously described control' apparatus as possible. Thus the supplemental knee plate 5| is a'djustably mounted on a supplemental extension 52 of'the rock lever 35, and the support i8 (Figs; 1 and 3) is arranged to have an adjustable height varied in accordance with the movement of the lifting rod 3|. 'Referring to Figs. 1 and 3, the support I8 is shown as comprising a member 53 upon which the end portion of spring I! is supported and which is eccentrically mounted for rotation by oppositely extending pintles 53-a and 53b. The pintle 53,'.b is rotatably supported in a suitable bore 54 in the arm 9, pintle.53a being supported in an alined bore 55 shown as formed in a detachable section 9-a of-the arm (Fig. 3).

.5 The member 53 has a crank arm or extension 51 with a pin 56 in its outer end engaging the slotted end 59 of a lever 60. The lever 69 is pivoted intermediate its ends on a pin 6 I mounted inarm 9 (Fig. 1). The opposite end 62 of the lever 66 is forked ;to accommodate the lifting rod 3|;(see also Fig. 2) and is provided with upwardly-facing convex surfaces -62a adapted to beenga ged by the under surface 32--b of abutment 32. Thus as the lifting rod 3| is moved downwardly from its normal position shown in the drawings, the abutment 32 will cause the lever 601:0 swingi'clockwise aboutthe pin 6 l1, whi will rotatemember, 53 inthe opposite directionto in:-

9, to facilitate assembly crease the effective height thereof under the supported end of spring This will flex spring upwardly about the adjusting screw l9 and increase the pressure on the presser bar.

The knee plate extensions 31 and 52 are secured to the rock lever 35 for independent adjustment by set screws 3'|-a and 5 |-a respectively. Thus by appropriate adjustment the knee plates 38 and 52 may be arranged to; encompass the operators knee and maintain the rock lever 35 in a neutral or normal position where the knee is comfortably placed. Thus byappropriate movement to the right, the primary pressure exerted by the presser foot may be reduced to the secondary great care or I press'uracr thefcotlifted to :clear the work. By

movement to thezleft; the primary'pressure may? be. increasedqtoa desired extents.

- The inventors claim: I

1. In; a. presser mechanism for) chineca pair of telescoping members; a presser foot'carried by one of the members; said members being provided with stops to limit inward and outward extensibility; means resiilently urging said members apart; means for applying a re silient force =on that member which. does not carry the foot, said force being greater than the force urging the members apart, whereby the members are inthe limiting inward position during: normal operation; means for optionally -releasing'said resilient force; and-means for optionally increasing said resilient force, including a reciprocably mounted member; "and means for movingthe said member.

2. In a presser mechanism ionasewing machine: a' presser bar; a flat spring having an end urging the bar downwardly, means forming an intermediate support for the spring, and an adjustable rest for the spring for adjusting the force exerted by the spring, comprising an angularly adjustable eccentric upon which the spring rests. J F 3.-'In asewing machine presser foot adapted to exert a primary pressure: means for causing said foot to exert a reduced pressure upon removal of the primary pressure, control means including a movable member having'a normal'position in which said foot exerts the primary pressure, and means whereby'movement of said member inone direction from said'normal'position renders said primary pressure ineffective, and movement in' another direction from said normal position .iner'eases the. primary pressure. V L 4'. In. a.. sewing machine'presser foot adapted opti'onallyfto'exert a pressure: control means for the presser foot, including a movable member having a normal position in which the foot exerts said pressure, means for increasing said pressure, and means whereby movement of said member from said normal position serves optionally to render. said pressure ineffective or toactuate the means to increase the pressure.

5. Ina sewing machine a presser foot adapted optionally to exert a primary pressure, a secondary pressure, or to be lifted clear of the work; control means for said foot, including a movable member having a normal position in which'said foot exerts primary pressure, and means whereby progressive movement of' said member in one direction from said'normalposition renders said primary pressure ineffective and lifts "the foot clear of the work, and movement in another direction causes said foot to exert increased pressure. i

.j ..6.:In a sewing Imachine .presserifoot and a presser bar, means :ioiningsaid foot to said bar a sewing ma includinga'lostmotion connection, means acting on said bar-to urge the foot against the. work comprising-a spring leaf one endof which engages the bar, a support forthe oppositeendofsaid leaf a pressure member intermediate said ends for flexing said spring leaf against-said bar. and said support, means for adjusting said support to alter the fiexure of said spring leaf and thereby adjust the force exerted by said spring on said bar, and means for lifting saidbar against the force of said spring, said lost motion connection causing saidfoot to remain in contact with the work for-a limited lifting movement of said bar, and spring means between said bar and said foot for urgingthe-foot against the work during said limited lifting movement. '7. In 4 a sewing machine presser foot anda presser bar, means acting on said bar to urge the footagainst the work comprising a spring leaf one end of which engages the bar, a support for the opposite end of said leaf, a pressure member intermediate said ends for flexing said spring leaf against said bar and said support, means forming an eccentric mounting for said support, movement of said support with respect to the mounting serving to vary the fiexure of said spring, and

means for moving said support.

8. In a sewing machine: a hollow elongate presser bar; means for guiding the presser bar in an axial direction; a presser foot; a shank'for the foot and telescoping within the hollow bar; spring means urging said bar downwardly; resilient means acting upon said Mr and shank for urgeing the shank outwardly of the bar; means limit ing said outward movement; and means operating-onsaid bar for raising it against the force of said spring means.

9. Ina sewing machine: hollow elongate presser bar: means for guidingthe presser bar-in an axial direction; a presser foot; a shank-for the foot telescoped Within the hollow bar;a' spring engaging said bar for urging said bar down? wardly; spring means within said bar urging said shank outwardly of the bar; means limiting said outward movement; and means operating on said bar for raising it against the force of said spring.

I TOBIAS KOTZIN.

JEROME C. IVEY.

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

UNITED STATES PATENTS 'Rubel' Apr. 10, I945

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