US3765350A

US3765350A - Sewing machine conversion assembly

Info

Publication number: US3765350A
Application number: US00091980A
Authority: US
Inventors: C Sztari
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-11-23
Filing date: 1970-11-23
Publication date: 1973-10-16
Anticipated expiration: 1990-10-16

Abstract

Apparatus for converting an ordinary sewing machine into a machine that will cut fabric. The apparatus comprises a cutter that is inserted into the sewing machine needle holder, a presser foot, a throat plate containing a recess adapted to permit the cutter to pass through and retaining means surrounding the recess. Two types of cutters each with a different blade design can be inserted into the needle holder, one cutter is capable of making a continuous straight cut and the other cutter is capable of making a continuous pinking cut.

Description

United States Patent 91 Sztari [4 Oct. 16, 1973 SEWING MACHINE CONVERSION ASSEMBLY [22] Filed: Nov. 23, 1970 [21] Appl. No.: 91,980

[52] U.S. Cl. 112/122 [51] Int. Cl D05b 37/00 [58] Field of Search 112/122, 128, 129, 112/130, 81, 82, 260, 123, 127; 206/66, 1 R, 16 R, 17

[56] References Cited UNITED STATES PATENTS 139,350 5/1873 Allen 112/128 1,891,308 12/1932 Gruman... 112/122 7 2,948,244 8/1960 Enos 112/260 2,048,268 7/1936 Kucera 112/128 1,264,886 5/1918 Bergwardt 112/123 X 691,203 1/1902 Sullivan ..112/128 X 3 ,459,293 8/1969 Vitale., .206/16 3,072,244 1/1963 Smith ..206/l7 1,980,705 ll/l934 Sigoda ..1 12/81 2,1 1/1939 Routtenberg.... 112/122 1,341,450 5/1920 Zawistowski 112/ 122 X 907,617 12/1908 Merrowm. 112/129 453,429 6/1891 Murphy. 112/128 323,439 8/1885 Ober 1 12/129 2,817,434 12/1957 Schmetz et al ..206/66 X Primary Examiner-H. Hampton Hunter Attorney-Donald J. Fitzpatrick [57] ABSTRACT Apparatus for converting an ordinary sewing machine into a machine that will cut fabric. The apparatus comprises a cutter that is inserted into the sewing machine needle holder, a presser foot, a throat plate containing a recess adapted to permit the cutter to pass through and retaining means surrounding the recess.

Two types of cutters each with a different blade design can be inserted into the needle holder, one cutter is capable of making a continuous straight out and the other cutter is capable of making a continuous pinking cut.

5 Claims, 13 Drawing Figures Pmammum 16 ms 9 k M k w k v Q BY DMM J. EJQ MM' ATTORNEY SEWING MACHINE CONVERSION ASSEMBLY BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a conversion kit adaptable for installation as a unit on a sewing machine. By utilizing the actuating mechanism of the needle arm the conversion kit rapidly transforms the sewing machine into a machine capable of cutting fabric.

2. Description of the Prior Art It is well known in the art that sewing fabric requires an assortment of cutting instruments. For example in cutting fabric when a pattern is used a pair of scissors and pinking shears are normally employedby the seamstress or dressmaker.

After the pattern is used to outline a design on the fabric, the design must be cut out. This is accomplished by hand cutting with a pair of scissors. Depending upon the type of fabric selected by the dressmaker this can be a slow and tedious operation. If the dressmaker is using a heavy fabric such as corduroy, tweed or an upholstery fabric, the cutting operation canalso be quite difficult and laborious. 7

Aside from the physical effort expended in hand cutting fabric the cutting instruments must be adequately maintained. If one attempted to cut out a pattern with dull and poorly maintained equipment this tedious task would be unnecessarily burdened.

SUMMARY OF THE INVENTION It is an object of this invention to provide a conversion kit that can be readily installed as a unit in a sewing machine thereby transforming the sewing machine into a machine capable of cutting fabric.

A further object of this invention is to provide a flat blade cutter that can be inserted into a sewing machine needle holder to produce a straight cut.

Still a further object of this invention is to provide a cutter with an angular blade that can be inserted into the sewing machine needle holder to produce a pinking cut.

The objects of this invention are achieved by inserting a specially designed cutter into a sewing machine needle holder in place of a sewing needle, by attaching a presser foot having a cutter accommodating aperture to a presser bar and by placing a throat plate having a recess cut therein to permit passage of the cutter bar into the sewing machine base throat plate aperture.

These and other objects will be apparent from the disclosure and claims which follow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a cutter inserted into a sewing machine needle holder and a presser foot attached to a presser foot bar.

FIG. 2 is a side view of a cutter used to produce a straight cut.

FIG. 3 is a front view of a cutter used to produce a straight cut and showing a beveled edge.

FIG. 4 is a top view of a cutter used to produce a straight cut.

FIG. '5 is a side view of a cutter used to produce a pinking cut.

FIG. 6 is a front view of a cutter used to produce a pinking cut and showing a larger second face.

FIG. 7 is a top view of a cutter used to produce a pinking cut, showing the perpendicularity of the two faces and showing a larger second face.

FIG. 8 is a top view of a presser foot showing a cutter accommodating aperture.

FIG. 9 is a side view of a presser foot.

FIG. 10 is an isometric view of a presser foot.

FIG. 11 is a top view of a throat plate showing recesses to permit passage of a cutter and a perimeter of material retaining means.

FIG. 12 is a perspective view of a cutter producing a straight cut in a fragment of work fabric.

FIG. 13 is a perspective view of a cutter producing a pinking cut in a fragment of work fabric.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings FIGS. 1 illustrates one embodiment of this invention. A conventional sewing machine 1 comprising a frame 2 and a base 3 contains means (not shown) for imparting reciprocation to a needle bar 4. Fastened to the needle baris a needle holder 5 and needle holder screw 6.

The sewing machine has a round presser bar 7, positioned adjacent the needle bar. The presser bar is provided with a flattened machined portion 8 and threaded fastener 9 which is adapted to accommodate a presser foot 22 as hereinafter more fully described.

Base 3 is provided with an aperture 10 wherein throat plate 28 is mounted.

Inserted into the needle bar is a cutter 11. FIGS. 2, 3 and 4 illustrate the cutter in greater detail. The cutter comprises a shank 12 and a blade 13. The shank consists of upper portion 14 and lower portion 15. The upper portion is provided with a flatened machined surface 16. When the cutter is inserted into needle holder 5 needle holder screw 6 exerts a holding force on surface 16.

Blade 13 consisting of face 17 and 18 is of thickness t. Beveled edges 19 and 20 extend in a curving concave are from the shank lower portion terminating at a blade point 21. The inventor has found that this design, a wide upper portion gradually tapering to a point is successful because, the point penetrates the fabric at the start of a needle bar reciprocation and the wide upper portion cleanly cuts the fabric at the end of the needle bar reciprocation.

The length 1 of the cutter should be the same as a standard sewing machine needle. A short cutter would not produce a satisfactory cut and a long cutter would strike the bobbin case at the end of the needle bar reciprocation.

FIGS. 8, 9 and 10 illustrate a presser foot 22. The presser foot is formed with a shank 23 and a sole plate 24 extending angularly from the shank bottom. A slot 25 is provided in a U-shaped shank upper portion 26. The sole plate is provided with a cutter accommodating aperture 27.

Sole plate width w is equal to the distance w between the outer edges of

feed dogs

32 and 34. By providing a presser foot with a wide sole plate the work fabric will be firmly held in place as it is cut. Area a of the cutter accommodating aperture 27 is equal to the throat plate area a, thereby permitting passage of cutter 1 1 as hereinafter more fully described.

The presser foot is attached to the presser bar by passing flattened machined portion 8 through the U- shaped shank upper portion 26 and engaging slot 25 on threaded fastener 9.

FIG. 11 illustrates a throat plate 28 another component of the inventors conversion kit which is adapted for insertion into base aperture 10. The throat plate is provided with slots 29, 30 and 31 wherein fabric feed dogs, 32, 33 and 34 respectively are permitted to protrude and engage and advance fabric placed on the sewing machine base. The throat plate contains recesses 35 and 36. Recess 35 is designed to accommodate the passage of cutter 11. The length and width of this recess being sufficient to permit passage of cutter 11 therein. Recess 36 concerns another embodiment of this invention and will be discussed hereinafter with that embodiment.

Forming a perimeter around the feed dog slots and recesses is retaining means 37. The inventor has discovered that when delicate work fabric such as voile, shantung or organdy are cut the cutter blade has a tendency to draw the fabric down into the recess. By providing a retaining means such as rubber, felt or cork sufficient traction is provided on the smooth, metallic throat plate thereby preventing material from being drawn into the recess. The retaining material should be nonadhesive so as not to hamper fabric advancing across the throat plate.

FIGS. 5, 6 and 7 illustrate another embodiment of the inventors conversion kit. These figures illustrate a cutter 41 that can produce a pinking cut. The cutter comprises a shank 42 and a blade 43. The shank of this embodiment is similar to the shank 12 of cutter 11 as hereinbefore described. The design of blade 43 distinguishes this cutter over the previously described embodiment.

The blade consists of a first portion 44 and a second portion 45 perpendicular to said first portion. Beveled edges 46 and 47 extend in a curving concave are from the shank lower portion terminating at a blade point 48.

As can be seen from FIGS. 6 and 7 first portion 44 is larger than second portion 45. The blade is designed in this manner so as to produce a clean out without any uncut fabric. As the cutter reciprocates in the needle bar each cut made by second portion 45 is slightly enlarged by the succeeding cut made by first portion 44. If the two portions were dimensionally equal there would be some uncut fabric and a clean cut could not be obtained.

Referring to FlG. 11 it can be seen that recess 36 is designed to accommodate the shape of blade 43. The dimensions of recess slots 49 and 50 are calculated to permit passage of first portion 44 and second portion 45 respectively. The inventor has found that having first portion 44 and second portion 45 set perpendicular to each other produces the most satisfactory cut.

FIG. 12 shows a piece of work fabric 51 being cut with cutter 11 thereby producing a straight cut 52.

FIG. 13 shows a piece of work fabric 53 being cut with cutter 41 thereby producing a pinking cut 54.

An ordinary sewing machine is converted into a machine capable of cutting fabric in the following manner:

An operator inserts a cutter 11 or 41 (depending upon the type of cut desired by the operator) into a needle holder 5. A presser foot 22 is fastened to a presser bar 7 and a throat plate 28 containing cutter recesses 35 and 36 is placed into base aperture 10.

The operator then adjusts the sewing machine stitch length and stitch width (adjusting means not shown) in order to obtain a satisfactory cut in the work fabric. This adjustment requires a little experimentation on the part of the operator because the stitch adjusting means varies between sewing machine models of different manufacturers.

As the needle bar 4 starts its downward actuation cutter blade 13 first penetrates and then cuts work fabric 51 or 53. As the needle bar starts its upward

actuation feed dogs

32, 33 and 34 advance uncut fabric beneath the cutter blade. The blade is actuated once again producing another cut, slightly overlapping the preceding cut and substantially in line with the preceding cut. This operation is continuted until the work fabric is cut in the desired manner.

It has been shown that throat plate 28 contains a pair of recesses to accommodate both embodiments. It can be appreciated that a throat plate can be provided wherein one recess is provided without departing from the spirit of this invention.

The features of the conversion kit can be modified or altered and such modifications or alterations as coming within the scope of the claims of this invention are deemed a part thereof.

I claim:

1. A conversion assembly for making a pinking cut adapted for installing as a unit in a sewing machine having a frame, a base with an aperture for a throat plate, a presser bar for a presser foot, a needle bar, means mounted in the frame for reciprocating the needle bar, means mounted in the base for feeding fabric, said conversion assembly comprising:

a. a cutter fixedly inserted into said needle bar, said cutter comprising i. a shank, and

ii. a blade having a pointed end for penetrating into fabric and a first curved concave beveled portion extending from said pointed end to said shank and a second curved concave beveled portion perpendicular to said first portion and extending from said pointed end to said shank;

b. a presser foot body fastened to said presser bar comprising:

1. a shank, and

ii. a flat sole plate equal to the width of said fabric feeding means projecting angularly of said shank and having a cutter accommodating aperture; and

c. a throat plate placed into said throat plate aperture and containing a recess therein to permit passage of said cutter blade.

2. A conversion assembly adapted for installing as a unit in a sewing machine having a frame, a base with an aperture for a threat plate, a presser bar for a presser foot, a needle bar, means mounted in the frame for reciprocating the needle bar, means mounted in the base for feeding fabric, for making a pinking cut, said conversion assembly comprising:

ii. a blade having a pointed end for penetrating into fabric and a first curved concave beveled portion extending from said pointed end to said shank and a larger second curved concove beveled portion perpendicular to said first portion and exof said cutter blade.

3. A conversion assembly as recited in claim 2 wherein said throat plate recess further comprises: a first recess and a larger second recess perpendicular to said first recess to permit passage of said cutter blade.

4. A conversion assembly as recited in claim 3 wherein said throat plate further comprises: a retaining means surrounding said recess to prevent material from slipping down into said recess.

5. A conversion assembly as recited in claim 4 wherein said retaining means is felt.

Claims

1. A conversion assembly for making a pinking cut adapted for installing as a unit in a sewing machine having a frame, a base with an aperture for a throat pLate, a presser bar for a presser foot, a needle bar, means mounted in the frame for reciprocating the needle bar, means mounted in the base for feeding fabric, said conversion assembly comprising: a. a cutter fixedly inserted into said needle bar, said cutter comprising i. a shank, and ii. a blade having a pointed end for penetrating into fabric and a first curved concave beveled portion extending from said pointed end to said shank and a second curved concave beveled portion perpendicular to said first portion and extending from said pointed end to said shank; b. a presser foot body fastened to said presser bar comprising: 1. a shank, and ii. a flat sole plate equal to the width of said fabric feeding means projecting angularly of said shank and having a cutter accommodating aperture; and c. a throat plate placed into said throat plate aperture and containing a recess therein to permit passage of said cutter blade.

2. A conversion assembly adapted for installing as a unit in a sewing machine having a frame, a base with an aperture for a throat plate, a presser bar for a presser foot, a needle bar, means mounted in the frame for reciprocating the needle bar, means mounted in the base for feeding fabric, for making a pinking cut, said conversion assembly comprising: a. a cutter fixedly inserted into said needle bar, said cutter comprising i. a shank, and ii. a blade having a pointed end for penetrating into fabric and a first curved concave beveled portion extending from said pointed end to said shank and a larger second curved concove beveled portion perpendicular to said first portion and extending from said pointed end to said shank so that during operation of said sewing machine the cut made by said first portion is enlarged slightly by said second portion thereby producing a clean cut in said fabric; b. a presser foot body fastened to said presser bar comprising: i. a shank, and ii. a flat sole plate projecting angularly of said shank and having a cutter accommodating aperture; and c. a throat plate placed into said throat plate aperture and containing a recess therein to permit passage of said cutter blade.