US2697992A

US2697992A - Blind stitcher

Info

Publication number: US2697992A
Application number: US233127A
Authority: US
Inventors: Harry N Johnson
Original assignee: Greist Manufacturing Co
Current assignee: Greist Manufacturing Co
Priority date: 1951-06-23
Filing date: 1951-06-23
Publication date: 1954-12-28
Anticipated expiration: 1971-12-28

Description

Dec. 28, 1954 H, N, JQHNSQN 2,697,992

BLIND STITCHER Filed June 23, 1951 V INVENTOR W ATTORN EYS United States Patent lO BLIND STITCHER Harry N. Johnson, New Haven, Conn., assignor to The Greist Manufacturing Company, New Haven, Conn., a corporation of Connecticut Application June 23, 1951, Serial No. 233,127

2 Claims. (Cl. 112160) This invention relates to an attachment for sewing machines and more particularly to an attachment for effecting a so-called blind stitch, which attachment may be applied to the ordinary sewing machine designed for household use.

It is desirable that a household sewing machine be equipped for accomplishing many kinds of work in addition to plain sewing, and in connection with the hemming of a piece of cloth, it is desirable to provide an attachment for effecting a so-called blind stitch in sewing the hem. This is accomplished in the present construction by providing an attachment which will produce a number of stitches in a straight line and at regular intervals effect an offset stitch or a stitch spaced from the line of stitching referred to.

The attachment is provided with a cloth-holding foot pivotally attached to a frame adapted to be secured to the presser bar of the sewing machine, and provision is made for shifting this foot pivotally at regular intervals in the operation of the machine to move the cloth laterally to effect an offset stitch. The cloth is then shifted back to its original position so as to continue stitching in a straight line until the lateral shift is again made to produce another offset stitch, it being understood that the offset stitch is produced at spaced intervals along the line of sewing.

Moreover, by the present construction there is provided a device of simple character which may be economically manufactured and which consists of a relatively small number of parts.

One object of the invention is to provide a new and improved blind stitch attachment for household sewing machines.

Another object of the invention is to provide a blind stitch attachment for sewing machines which will be relatively simple in construction and which will comprise a relatively small number of movable parts subject to wear.

Still another object of the invention is to provide a blind stitch attachment for sewing machines comprising elements which will be readily and accurately manufactured by stamping operations and easily assembled into the completed mechanism.

A still further object of the invention is to provide a new and improved blind stitch attachment for sewing machines comprising a frame and a cloth-holding foot pivoted to the frame and means for effecting lateral oscillations of the cloth-holding foot about its pivot, which means comprises a cam member having spaced lugs thereon to engage a pin or boss upon the pivoted foot member.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a side elevational view of a blind stitch attachment for sewing machines embodying my invention;

Fig. 2 is a top plan view thereof;

Fig. 3 is a view similar to Fig. 2 showing the clothholding foot in another position;

Fig. 4 is a sectional view on line 4-4 of Fig. 3; and

Fig. 5 is a perspective view of the cam member.

`To illustrate a preferred embodiment of my invention I have shown in the drawing an attachment for effecting blind stitching comprising a main frame of substantially U-shaped form in cross section, this frame comprising a base member and

upstanding side members

11 and 12. The base member 10 is continued forwardly beyond the upstanding side members and provided upon its for- "ice ward end with an adapter 13 by which it may be secured to the presser bar of the sewing machine. The base member is also provided with laterally

elongated openings

14 and 15 for a purpose to be hereinafter described.

A pin 16 is secured to the base member and projects downwardly therefrom, and upon this pin is pivoted a lever 17 having upon its forward end a downwardly displaced cloth-holding foot 18 provided with a laterally enlarged needle opening 19. A cloth guide 20 is adjustably secured to the foot 18 by means of the pin 21 and slot 22 so that the guide member may be adjusted relatively to the needle opening.

The rear portion of thislever 17 is offset upwardly from that part which engages the pin 16, as shown at 23, so that this portion of the lever lies substantially flatly against the underside of the base 10 of the frame. Upon the portion 23 of the lever is provided an opstanding pin or boss 24 which projects upwardly through the opening 14, and at its rear end the portion 23 of the lever is provided with a pin 25 which projects through and is guided by the elongated slot 15 in the base member 10. The pin 24 may be provided with a roller or anti-friction sleeve, if desired, to be engaged by the operating cam as will be described hereinafter.

Rotatably mounted in the upstanding portion 12 of the frame, as shown more especially in Fig. 4, is a short shaft 27, and secured to this shaft is a ratchet wheel 28. Loosely mounted upon the shaft 27 is a fork arm 29 upon which is pivotally mounted a pawl 30, the free end of which is urged into engagement with the teeth of the ratchet wheel 28 by a spring 31. As will be well understood by those skilled in the art, the fork arm is adapted to be secured to the needle bar of the Sewing machine, and upon reciprocation of the needle bar the oscillations of the fork arm will rotate the ratchet wheel and shaft 27 in a step-by-step movement.

The shaft 27 extends through the portion 12 of the frame and upon its inner end is secured a cam disk 32 by means of the screw 33. As shown in Fig. 5, this cam disk may be of substantially circular form and is provided at diametrically opposite points with cam members or

fingers

34 and 35. The forward edges of these members may be rounded or beveled off, as shown at 36 and 37, as these are the active faces of the cam members.

As shown in Fig. 4, the cam disk 32 is so disposed that its lower portion lies adjacent the pin 24 which is secured to the pivoted lever 17 so that upon rotation of the cam the rounded or beveled edges of the

cam fingers

34 and 35 will strike the pin 24 and effect movement of the pin and of the rear end of the lever away from the side frame 12 or to the left, as shown in Fig. 4. A leaf spring 38 is secured at one end to the upstanding frame member 11 and the free end of this spring bears against the pin 25 to urge this pin toward the frame member 12 and maintain the lever 17 in the position shown in Pig. 2 when the pin 24 is not in contact with one of the

cam fingers

34 and 35.

The ratchet wheel 28 may be prevented from rotatingin a reverse direction, during oscillation of the fork arm 29, by means of a holding pawl in the form of a spring 39 secured to the rear portion of the frame member 12 and projecting forwardly into engagement with the teeth of the ratchet wheel. It may also be noted that the pin 25 which is secured to the portion 23 of the lever 17 is provided with an enlarged head which lies above the base member 10, while the pin 16 is provided with an enlarged head which lies below the lever 17, thus attaching the lever to the frame member while permitting pivotal movements thereof.

The operation of the device is as follows. Upon oscillation of the fork arm 29 the ratchet wheel is rotated in a step-by-step movement which serves to rotate the cam disk 32 in a similar manner. The ratchet wheel is provided with a number of teeth, in this instance 12, and it will be seen, therefore, that as there are two of the

cam members

34 and 35, one of these members will come into engagement with the pin 14 upon every sixth stitch or oscillation of the fork arm 29. When one of these cam members reaches its lowermost position, as shown in Fig. l adjacent the pin 24, the rounded or beveled surface 36 of the cam member will engage this pin and move it from the position shown in Fig. 2 at one end of the slot 14 to the position shown in Fig. 3 at the other end of this slot.Y This will move the lever 17 from the position shown in Fig. 2 to that shown in Fig. 3 and thus move the cloth laterally of the regular line of stitching. Upon the next descent of the needle bar a laterally offset stitch will be made, and when the needle bar again ascends, the cam member will be moved out of engagement with the pin 24 and the lever 17 will be returned to the position shown in Fig. 2 by the spring 38. Upon continued oscillation of the fork arm 29, a series of straight stitches will result until the other cam member reaches a position to engage the pin 14. At this time another lateral movement of the lever 17 will be effected to produce another laterally offset stitch.

It will, of course, be understood that the ratchet wheel may have as many teeth as desired, and as many of the

cam members

34 and 35 may be provided as desired. With the present arrangement of twelve teeth on the ratchet wheel and two cam members, the resulting stitch will consist of a lateral offset stitch between series of five straight-line or regular stitches. As shown in Fig. 3, it will be noted that the high point of one of the

cam members

34 and 35 will remain in engagement with the pin 14 during the descent of the needle bar to make the laterally offset stitch in order to hold the lever in the position shown in Fig. 3 while this stitch is being made. l While I have shown and described a preferred embodiment of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modication and variation within the spirit of the invention and within the scope of the claims.

What I claim is:

l. In a blind stitch attachment for sewing machines,

a frame comprising a horizontally disposed base member having an elongated opening therein and upstanding side kmembers at each side of the base member, a lever pivoted to the base member having a cloth-engaging foot at its forward end, said lever having an upwardly projecting pin thereon extend-ing through said opening, a horizontally disposed shaft rotatably mounted on one of said side members, a cam disk secured to said shaft, a pair of spaced diametrically opposite laterally projecting cam members on said disk to engage said pin and move the lever about its pivot, means to rotate said shaft in a stepby-step movement, said last-named means comprising a fork arm pivoted on the shaft, and a spring secured to the other of said upstanding members and acting horizontally against said pin to urge it toward the disk.

2. In a blind stitch attachment for sewing machines, a substantially U-shaped frame comprising a horizontally disposed base member and upstanding side members, one at each edge of the base member, said base member having an elongated opening therein, a lever pivoted to the base member at the underside thereof having a cloth-engaging foot at its forward end, said lever having an upwardly projecting pin thereon extending through said opening, a rotatable cam disk mounted on one of said upstanding side members to rotate on a horizontal axis, said disk having a pair of spaced diametrically opposite laterally projecting cam members thereon to engage said pin, means to rotate said disk, and a spring secured to the other of said upstanding members having a free end engaging said pin to urge it toward said disk.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,067,419 Fefel July 15, 1913 FOREIGN PATENTS Number Country Date 651,773 Germany Oct. 19, 1937