US2504069A

US2504069A - Stripper feet for buttonhole attachments

Info

Publication number: US2504069A
Application number: US50482A
Authority: US
Inventors: John P Enos
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1948-09-22
Filing date: 1948-09-22
Publication date: 1950-04-11
Anticipated expiration: 1967-04-11

Description

April 11, 1950 J. P. ENOS STRIPPER-FEET FOR BUTTONHOLE ATTACHMENTS Filed Sept. 22, 1948 2 Sheets-Sheet l wit 0 1244 April 11, 1950 J, os 2,504,069

STRIPPER-FEET FOR BUTTONHOLE ATTACHMENTS Filed Sept. 22, 1948 2 Sheets-Sheet 2 OAMQEW Patented Apr. 11, 1950 STRIPPER FEET FOR BUTTONHOLE ATTACHMENTS John P. Enos, Union, N. 3., assignor to The Singer Manufacturing Company, Elizabeth, N. 3., a corporation of New Jersey Application September 22, 1948, Serial No. 50,482

This invention relates to buttonhole attachments for domestic sewing machines and particularly to that type of attachment which is removably secured to and carried wholly by the presser-bar of the machine and actuated by the reciprocating needle-bar, as distinguished from that type which is secured to the cloth-plate or other portions of the machine frame.

Attachments of this nature, as heretofore constructed, have included a work-engaging and work-shifting element having a rectangular opening beneath which the buttonhole is formed in the underlying workpiece. This opening must be sufiiciently large to accommodate the largest buttonhole to be made and therefore, necessarily, is of substantial dimensions. While attachments of this nature have been satisfactory for producing buttonholes in most materials, it has been found that in very thin and sleazy materials there is a tendency for the material to flag, that is to pulsate with the up and down movements of the needle. This flagging of the material has caused the skipping of stitches and has interfered with the proper stitching of the buttonhole.

This invention has as an object to provide, in a presser-bar-carried type of buttonhole attachment, a presser device or stripper-foot which will bear upon the work adjacent the needle during that portion of the stitch forming cycle when the needle is entering and withdrawing from the material and which will thereafter be lifted from the material to permit the material to be shifted relative to the needle to cause the next stitch to be positioned properly.

Another object of the invention is to provide,

attained thereby, will be readily understood by r those skilled in the art.

In the drawings,

Fig. 1 is a front elevation of a portion of a sewing machine showing the improved buttonhole attachment applied thereto.

Fig. 2 is an elevation looking from the left of 7 Claims. (Cl. 112-77) Fig. 1, with the rear portion of the attachment broken away.

Fig. 3 is a vertical sectional view'taken substantially on the line 33 of Fig.1, also with the rear portion of the attachment broken away.

Fig. 4 is a plan view of the forward end portion of the attachment with the presser-bar and needle shown in section.

Fig. 5 is an exploded perspective view of the frame for securing the attachment to the presserbar of a sewing machine, of the presser device which is slidingly mounted on said frame, and of the means actuated from the needle-bar for lifting the presser device.

Referring more specifically to the drawings, the invention is disclosed as embodied in a buttonhole attachment adapted to be secured to, the presser-bar I and to be actuated by the reciprocatory movements of the needle-bar 2 of a conventional domestic sewing machine. In the drawings the bracket-arm head of the sewing machine is designated as 3 and the work-supporting cloth-plate as 4. The cloth-plate carries the usual throat-plate 4 The stitch-forming mechanism of the machine is shown as comprising an eye-pointed thread carrying needle 5 carried by the needlebar and a cooperating loop-taker 6 journalled beneath the cloth-plate i. The needle 5 is secured to the needle-bar 2 by a clamp-collar I secured to and reciprocating with the needle-bar and having a cylindrical portion '1 which actuates the buttonhole attachment, as hereinafter described. The feeding mechanism of the sewing machine, which is rendered ineffective to feed the work during the use of the buttonhole attachment, is designated generally as f. l

The buttonhole attachment comprises a supporting frame including a bracket 8 adapted to be attached to the presser-bar l by a knurled thumb-screw 9, in place of the usual presserfoot, and a U-shaped sheet metal portion H] attached to the bracket 8 as by pins ll whichproject through apertures 8 in the bracket 8 and through apertures Mi in the upstanding side walls It lfl of the sheet metal portion I 0. Rigidly secured to the under side of the portion it is a base-plate 52 which carries, at its under side, a slidingly and pivotally mounted plate 13 having, at its front end, spaced and downturned fingers 13 Pivotally mounted on the fingers l3 is a rectangular work-clamping member l4 having a serrated under surface I v l adapted to grip and shift a workpiece placed upon the clothplate 4. The work-clamping member I4 is formed with a. rectangular opening M beneath which the buttonhole is sewed in the underlying workpiece.

Pivotally mounted on a stub shaft I5, journalled in apertures I6 in the upstanding side walls I III of the bracket portion I0, is an operating lever I! having a forked end H which straddles the cylindrical portion I of the needle-clamp collar. Fixed to the shaft l5 between the side walls I0, I0, by a set screw I8, is a barrel cam I9. Also secured to the shaft I5 at the outer face of the side wall HP is a ratchet wheel which is engaged by a spring-pressed pawl 2I carried by the lever I'I. Thus reciprocation of the needle-bar causes the operating lever to be oscillated about the stub shaft I5 and the oscillatory movements of this lever effects step-by-step rotation of the ratchet wheel 20, shaft I5 and the cam I9. Rotation of the cam I9 effects, through mechanism not disclosed, lateral vibratory movements and back and forth endwise feeding movements of the plate I3 and the work-clamping member I4 carried thereby, in timed relation with the reciprocations of the needle, to cause the stitchforming mechanism to sew a buttonhole in that portion of a workpiece located beneath the rectangular opening I I in the work-clamping mem- All of the mechanism above described is conventional and forms no part of the present invention.

As hereinbefore indicated, it has been found that, during the sewing of a buttonhole in certain types of material, the portion of the workpiece below the opening I4 in the work-holding member I4 tends to flag, that is to move up and down with the needle, thereby causing the skipping of stitches and interfering with the proper formation of the buttonhole. To overcome this difficulty, this invention has provided an improved form of presser device or so-called stripper-foot which bears on the workpiece closely adjacent the needle and holds the workpiece down on the throat-plate 4 at all times except during the actual shifting of the workpiece. 'This presser device is actuated from the oscillatory operating lever I1 and comprises an upright shank member 22 slidingly mounted in

guideways

23, 24 provided by the side wall IIJ of the supporting frame I 0. At its lower end the member 22 is formed with an offset portion 22 which carries a horizontally disposed stripperfoot 25, which, as shown most clearly in Fig. 4, is adapted to bear upon the workpiece immediately behind the needle 5. At its upper end the presser member 22 is formed with an offset arm 4 22 to which is secured one end of a coil spring 26, the other end of the spring being connected with the side wall Ill The spring is constantly maintained under tension and therefore constantly tends to urge the member 22 and its foot 25 downwardly to cause the foot to bear upon the workpiece. The presser member 22 is adapted to be lifted periodically, in opposition to the spring 26, by the oscillatory movement of the operating lever I I. This is effected by means of a first two-armed lifting lever 21 fulcrumed on a screw 28 threaded into an aperture 29 in the side wall lo (Fig. 5) with its axis parallel to the axis of the stub shaft I5. One arm 21 of the lever 21 engages beneath the arm 22 of the member 22 while the other arm 2'I thereof is engaged by one arm of a second two-armed lifting 1ever 30. The lever 30 is fulcrumed on a shoulder screw 3| which passes through an aperture 32 formed in an offset portion In (Fig. 5) of the frame side wall I0", and is held therein by a nut 33. The fulcrum axis of the lever 30 is transverse to the fulcrum axes of the lever 21 and the operating lever H. The other arm 30 of the lever 30 is bent laterally and has a downturned end portion 30 which bears upon the upper edge of the operating lever I! under the influence of the spring 26, acting through the ann 22 and lever 21. During the downward movement of the lever H the arm 30' of the lever 30 follows the lever I'I until the lever 30 engages an offset abutment III carried by the portion IIJ of the frame member I0. Thereafter the lever H has a further downward movement which produces a slight lost motion between the levers I1 and 30.

During the operation of the machine, the presser member 22 is lowered with the needle until the stripper-foot 25 bears upon the workpiece. Immediately thereafter the point of needle enters the workpiece. Due to the lost motion between the levers I1 and 30 the stripper-foot continues to bear upon the workpiece while the needle continues to descend and until the point of the needle has again been raised above the workpiece. Thus the workpiece is held down on the throat-plate adjacent the needle during the critical stage of the stitch forming cycle and therefore flagging of the material and the diificulties heretofore caused thereby are completely obviated.

Having thus set forth the nature of the invention, What I claim herein is:

l.- A buttonhole attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a frame including a supporting bracket secured upon the presser-bar; a base-plate carried by said frame; a shiftable work-clamping element supported on said base-plate and provided with an opening through which a buttonhole is sewed in an underlying workpiece; means including an operating lever pivotally mounted on said frame and actuated by said needle-bar for shifting said work-clamping element; a stripper-foot engaging the workpiece adjacent the needle; and means actuated from said operating lever and including a second lever pivotally mounted on said frame and having its pivotal axis spaced from the pivotal axis of said operating lever for raising and lowering said stripper-foot in timed relation with the reciprocations of said needle-bar.

2. A buttonhole attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a supporting frame secured upon the presser-bar and having a U-shaped sheet metal portion; a base-plate carried by said frame; a shiftable work-clamping element supported on said base-plate and provided with an opening through which a buttonhole is sewed in an underlying workpiece; means including an operating lever pivotally mounted on the U-shaped portion of said frame and actuated by said needle-bar for shifting said work-clamping element; a stripper-foot having a shank portion movably mounted on the U-shaped portion of said frame and a foot portion engaging the workpiece adjacent the needle; and means including a second lever pivotally mounted on the U-shaped portion of said frame and actuated by the movement of said operating lever for raising and lowering said stripper-foot in timed relation with the reciprocations of said needle-bar.

3. A buttonhole attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a supporting frame secured upon the presser-bar and having a U-shaped sheet metal portion; a base-plate carried by said frame; a shiftable work-clamping element supported on said base-plate and provided with an opening through which a buttonhole is sewed in an underlying workpiece; means including an operating lever pivotally mounted on the U-shaped portion of said frame and actuated by said needlebar for shifting said work-clamping element; a stripper-foot having a shank portion movably mounted on the U-shaped portion of said frame and a foot portion engaging the workpiece adjacent the needle; and means actuated by said operating lever and including a lever pivotally mounted on the U-shaped portion of said frame and having its pivotal axis spaced from and parallel to that of said operating lever for raising and lowering said stripper-foot in timed relation with the reciprocations of said needle-bar.

4. A buttonhole attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a supporting frame secured upon the presser-bar and affording a vertically disposed guideway; a base-plate carried by said frame; a shiftable work-clamping element supported on said base-plate and provided with an opening through which a buttonhole is sewed in an underlying workpiece; means including an operating lever pivotally mounted on said frame and actuated by said needle-bar for shifting said workclamping element; a stripper member having a shank portion slidingly mounted on said guideway and a foot portion engaging the workpiece adjacent the needle; and means including a lever pivotally mounted on said frame and having one portion connected with the shank of said stripper member and another portion operatively connected with said operating lever for raising and lowering said stripper member in timed relation with the reciprocations of said needle-bar.

5. A buttonhole attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a supporting frame secured upon the presser-bar and affording a vertically disposed guideway; a base-plate carried by said frame; a shiftable work-clamping element supported on said base-plate and provided with an opening through which a buttonhole is sewed in an underlying workpiece; means including an operating lever pivotally mounted on said frame and actuated by said needle-bar for shifting said workclamping element; a stripper member having a shank portion slidingly mounted on said guideway and a foot portion engaging the workpiece adjacent the needle; and means including a pair of interconnected levers pivotally mounted on said frame, one of said levers being operatively connected with said operating lever and the other operatively connected with said stripper member, for raising and lowering said stripper-foot in 6 timed relation with the reciprocations of said needle-bar.

6. A buttonhole attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a supporting frame secured upon the presser-bar and affording a vertically disposed guideway; a base-plate carried said frame; a shiftable work-clamping element supported on said base-plate and provided with an opening through which a buttonhole is sewed in an underlying workpiece; means including an operating lever pivotally mounted on said frame and actuated by said needle-bar for shifting said work-- clamping element; a spring depressed presser member including a shank portion slidingly mounted on said guideway and a foot portion engaging the workpiece adjacent the needle; and means including a first lifting lever pivotally mounted on said frame with its pivotal axis parallel to the pivotal axis of said operating lever, one arm of said lifting lever engaging the shank portion of said presser member, and a second lifting lever pivotally mounted on said frame with its pivotal axis transverse to the axis of said first lifting lever, one end of said second lifting lever engaging said operating lever and the other end thereof engaging the other arm of said first lifting lever, said operating lever and lifting levers serving to transmit lifting movements to said presser member in timed relation with the upward movements of said needle-bar.

7. An attachment for a sewing machine having a presser-bar and a reciprocating needle-bar carrying an eye-pointed needle; comprising a frame including a supporting bracket constructed and arranged to be secured upon the presserbar; a horizontally disposed plate carried by said frame; work-clamping means supported by said plate comprising spaced work-engaging portions; means including an operating lever pivotally mounted on said frame and actuated by said needle-bar for shifting said Work-clamping means; a foot constructed and arranged to engage a workpiece between said work-engaging portions of said work clamping means and adjacent the needle; and means actuated from said operating lever and including a second lever pivotally mounted on said frame and having its pivotal axis spaced from the pivotal axis of said operating lever for raising and lowering said foot in timed relation with the reciprocations of said needle-bar.

JOHN P. EN OS.

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

UNITED STATES PATENTS Number Name Date 442,695 Powell Dec. 16, 1890 549,538 Schoonmaker Nov. 12, 1895