US2533746A - Attachment for sewing machines - Google Patents

Description

Dec. 12, 1950 P. J. STUSTER 2,533,746

ATTACHMENT FOR SEWING MACHINES Filed NOV. 1, 1948 INVENTOR Philip J. Stuster ATTORNE Patented Dec. 12, 1950 U N I T E D S TATE S PATEN T PF! CE ATTACHMENT FOR SEWING MACHINES Philip J. Stuster, Huntington Park, Galif.

Application'November 1, 1948 'Serial'No. 57,694

"The present invention relates "generally to attachments for sewing machines, and more especially to attachments which provide means for adjusting or regulating the pressure applied to the work by the presser bar.

This is especially f b'eing handled, the pull of the thread, or various other factors encountered in sewing.

There have been some attachments devised for this purpose, but so far as known these have not been entirely satisfactory. For example, a device which permits only a maximum or minimum pressure is not satisfactory because it does lnotfafford enough variations in pressure. Other devices have not been positive in their action, that is they cannot be relied upon to maintain a definite Setting after adjustment, or else they are too slow and difficult to manipulate to provide the desired variation. Devices of this latter class are of very little value since the machine operator cannot take the "time to change the settings, especially when many'frequent changes :are desired.

Hence it becomes .a general object of "my invention to provide an attachment for a sew- 'ing machine which enables a wide selection of pressures to be exerted by the ipresser bar and ,jpress'er 'Ioot.

It is also another object of .my invention to provide an attachment of this character which is positive in its operation and is adapted "to jl'emain securely in any "adjusted position.

It is a further object of my invention to provide an attachment of this character which is not only simple in its manufacture and construction,but is also quick and easy of manipula- 'jti'on so that the machine operator can obtain any desired setting with a minimum of time and so obtain a maximum amount of benefit from the attachment.

I have attained these and other objects in a pressure regulator constructed according to my invention by providing a sleeve which is slidably mounted on the upper end of the conventional presser bar with the lower end of the sleeve'bearing against the upper end of the conventional compression spring.

is usually a coil spring which surrounds the This spring presser bar and bears at its lower end against a 27 Claims. (01. 11.-223'6f) transverse member attached to the presser bar so "that the compressive *force exerted by the spring is transmit-ted to the presser bar and' to the foot onthe 'lower end of the bar. A collar surrounding at least .a part of the sleeve i's -held stationary by engagement with the frame ot the sewing machine. The external surface of 'the'sleeve is serrated in a manner to provide a pression of the spring and hence increase the force on the presser'bar.

How the above objects and advantages of my invention, as well as others not specifically :mention'ed herein, are attained will be more fully and readily understood by reference to the $01- I lowing description, and to the annexed drawings,

:in which:

Fig. '1 is an end elevation of a conventional type of sewing machine with .a portion of the end cover plate broken away in order *to show the presser bar and associated spring, ta pressure regulator constructed according to my inven- 'tion being "mounted on the upper end of the presser bar; "Fig. 2 is a fragmentary vertical section taken on line 2-'2 of Fig. 1';

Fig. '3 is a horizontal section through the pressure regulator taken on line 3-3 of Fig.1; :and

liig. 4 is a fragmentary elevation of 1a variational form of sleeve for their-regulator.

Fig. '1 shows 'in elevation the end of a conventional type of sewing machine comprising a frame Iii on which the end cover plate 12 has been partially broken away in order to show the pertinent parts of the interior mechanism. Mounted for vertical reciprocation in machine frame it, is needle bar 14 and presser bar 315 which carries on its lower end presser foot "16 which-is associated with needle t? on the lower "endof needle bar 44.

' At a point intermediate its ends, presser bar I 5 has attached to it a'transverse bar 2553 against which bears the lower end of @011 spring 212 which is mounted on the presser bar. The presserlbar may be lifted and held in raised position by means of cam handle 24 pivotally mounted on the machine frame and provided with cam 25 which engages the under side of transverse bar 20 to lift the presser bar when handle 24 is lifted or rotated clockwise as viewed in the figure. The mechanism so far described is conventional and well known and forms no part of the present invention. It is described here in order that my invention, as well as its application to'a sewing machine, may be more fully understood.

The pressure regulator, or darning attachment, as it is sometimes called, is mounted on the machine at the upper end of the presser bar and is generally indicated in the drawings at 26. It consists of an outer hollow collar 28 which is threaded at its lower end so that it can be screwed into a suitable threaded bore 29 in machine frame III, as shown best in Fig. 2. Collar 28 receives with a loose sliding fit sleeve 31] which is also hollow and is slidable on the upper end of presser bar IS with the lower end of the sleeve bearing against the upper end of spring 22 around the presser bar. The sleeve is here shown as being directly in contact with spring 22 but a washer or the like may be inserted if desired between the Any ', Spring 22 is normally maintained under cornpression between sleeve 3!) and transverse bar 20, the compressive force exerted by the spring being transmitted to the presser bar through the connection of transverse member 29 to the presser bar. Naturally the spring pressing against the lower end of sleeve 39 urges it upwardly; and in order to maintain compression on the spring it is necessary to provide means for holding the -'sleeve and collar against relative movement in order to maintain the compression on the spring. For this purpose, the upper part of the external surface of sleeve 33 is serrated in such a manner as to produce a longitudinally spaced series of "teethJhaVing upwardly facing and radially extending surfaces. This is done preferably by proyiding the sleeve with a plurality of circumferential ridges 32 each of which has an upper face 33 that faces upwardly and is substantially radial or normal to the length of collar 30, and a lower inclined face 34 which is inclined downwardly and inwardly toward the axis of the sleeve. The number of these ridges, and hence the spacing between successive surfaces 33, may be as much or as little as desired, but I find it convenient and satisfactory to provide about six such faces within the normal travel of sleeve 30.

There is provided on collar 28 latch means which is engageable with any selected one of the several faces 33 and which is adapted, by such engagement, to hold the sleeve in a selected position against the upward movement induced by spring 22. This latch means is shown best in Fig. 3, and comprises lever 36 pivotally mounted i on the collar by pin 31. The lever is bent or curved and is located partly in slot 38 which extends through the collar wall for a fraction of its periphery. Lever 36 is provided at one end with an inwardly projecting lug 360. which can 4 be moved into position to engage any one of the radial surfaces 33. The other end of the lever is provided with a handle 361) by means of which the lever can be manually manipulated.

Latch as is normally urged toward the position of Fig. 3, in which it engages sleeve 30', by means of wire spring 40 which is fastened to collar 28 at one end and at the other end seats in. a notch in lever 33 opposite lug 36a.

The operation of the device will be readily apparent from the foregoing description and the drawings. When the machine operator manually depresses sleeve 30, spring 22 is compressed and a correspondingly greater force is exerted on presser bar l5. At any position in which one of the radial faces 33 engages the under side of lever 36, the latch holds the sleeve against upward movement relative to the presser bar and collar 28; and the amount of compression in spring 22 depends upon how far the sleeve has been depressed or which one of the radial faces is in engagement with the latch means.

If the end 36b of the latch lever is manually pressed toward th collar, the other end moves out of engagement with the radial faces on the sleeve and the s eeve is then free to move within collar 28 relative to the collar and the presser bar. While the latch is in its normal or engaging position, as shown in Fig. 3, the collar can be moved downwardly without manual manipulation of the latch means by simply pressing on the upper end of the sleeve. Downward movement of the sleeve causes a downwardly facing inclined surface 34 to engage projection 33a and, by cam action, to move the latch lever outward-a sufficient distance to allow the sleeve to move down at least to the next radial face. At all times spring 40 urges projection 36a inwardly toward a sleeve-engaging position so that the sleeve is immediately engaged and held in any adjusted position when downward pressure on it is released.

I have described above a form in which circumferential ridges 32 provide one form of a series of longitudinally spaced shoulder means. 01)- viously the ridges can be made as a spiral or screw thread as shown at 32a in Fig. 4. The faces are still radial and are in an axially spaced row, when viewed in section, but havea slight tilt that can be compensated for by incliningjproj'ection 360. on the latch means. I

From the foregoing description of a preferred embodiment of my invention it will be evident that various changes in the construction ,may be made by persons skilled in the art without departing from the spirit and scope of my inven tion; and consequently I wish it understood that the foregoing description is considered as being illustrative of, rather than limitative upon, the appended claims.

I claim:

1. A pressure regulator for a presser bar assembly having a compression spring that forces the presser bar downwardly, comprising: a stationary collar; a sleeve slidable within the collar and bearing against the upper end of the spring, the sleeve having a plurality of axially spaced radially extending external faces; and latch means carried on the collar engageable with a selected radial face to hold the sleeve against relative upward movement.

2. A pressure regulator as in claim 1 in which the latch means is manually disengageable from the sleeve faces to permit freemovement of the I sleeve, and also includes spring means normally urging the latch means toward the face enaging position.

3. A pressure regulator for a presser bar assembly having a compression spring that forces the presser bar downwardly, comprising: a stationary collar; a sleeve slidably carried by the collar and bearing against the upper end of the spring, the sleeve having a plurality of axially spaced circumferential ridges each of which has an upper radial face and a lower inclined face; and latch means carried on the collar engageable with a selected radial face to hold the sleeve against relative upward movement, the latch means being retractable by engagement with an inclined face during downward movement of the sleeve to increase the spring compression.

4. A pressure regulator for a presser bar assembly having a compression spring that forces the presser bar downwardly, comprising: a stationary collar; a sleeve slidably carried by the collar and bearing against the upper end of the spring, the sleeve having a plurality of axially spaced radially extending external faces; a latch member pivotally mounted on the collar and movable into engagement at one end with a selected radial face to hold the sleeve against upward movement; and a spring normally urging the latch into said engagement.

5. A pressure regulator for a presser bar assembly having a compression spring that forces the presser bar downwardly, comprising: a stationary collar; a sleeve slidably carried by the collar and bearing against the upper end of the spring, the sleeve having an external spiral ridge forming an axial row of spaced radially extending faces; and latch means carried on the collar engageable with a selected radial face to hold the sleeve against relative upward movement.

6. In means for varying the pressure imposed upon the presser foot of a sewing machine having a head, said foot being carried upon the lower end of a presser bar of which the upper end is longitudinally movable in said head under the pressure of a spring thereon, the combination comprising: a stationary collar adapted to be fixed upon said sewing machine head; an inwardly projecting member carried on the collar; and a sleeve slidably carried on said collar and provided with a plurality of longitudinally spaced shoulder means selectively engageable with said inwardly projecting member to lock the sleeve in any one of a plurality of predetermined positions intermediate the extremes of its slidable movement in opposite directions to place said spring under correspondingly different compressions.

'7. In means for varying the pressure imposed upon the presser foot of a sewing machine having a head, said foot being carried upon the lower end of a presser bar of which the upper end is vertically movable in said head under the pressure of a spring thereon, the combination comprising: a stationary collar adapted to be fixed upon said sewing machine head; a sleeve slidably carried by said collar for movement to a plurality of intermediate positions between the extremes of its slidable movement in opposite directions to place said spring under correspondingly different compressions, said sleeve having a plurality of shoulder means spaced apart in the direction of sliding movement; and a lock member carried on the collar and engageable with a selected one of said shoulder means for holding the sleeve in any of said intermediate positions of adjustment.

PHILIP J. STUSTER.

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

UNITED STATES PATENTS Numer Name Date 2,012,157 Corson Aug. 20, 1935 2,193,098 Huenergarde Mar. 12, 1940

Images