US2684649A

US2684649A - Device for embroidering automatically with zigzag sewing machines

Info

Publication number: US2684649A
Application number: US229059A
Authority: US
Inventors: Scarpa Giuseppe
Original assignee: VITTORIO NECCHI SpA
Current assignee: Vittorio Necchi S P A; VITTORIO NECCHI SpA
Priority date: 1950-07-25
Filing date: 1951-05-31
Publication date: 1954-07-27
Anticipated expiration: 1971-07-27

Description

July 27, 1954 a. SCARPA 2,684,649

DEVICE FOR EMBROIDERING AUTOMATICALLY WITH ZIGZAG SEWING MACHINES Filed May 31, 1951 2 Sheets-Sheet l R4 4. w 11 wwwma M4 ATTYS.

July 27 1954 s. SCARPA 2,684,649

DEVICE FOR EMBROIDERING AUTOMATICALLY WITH ZIGZAG SEWING MACHINES 2 Sheets-Sheet 2 Filed May 31, 1951 INVFIVTOR. 6 Scar 2a, B) @7775.

Patented July 27, 1954 Giuseppe Scarpa, Pavia, Italy, assignor to Vittorio Necchi S. p. A., Pavia, Italy, a firm Application May 31, I951, Serial/1N0. 229,059

Claims priority, application Italy July 25, 1950 3 Claims. 1

There are known sewing machines for zigzag sewing, with which it is possible to obtain seam-s the successive stitches of which arrange as straight segments inclined in respect to one another in such a manner as to generate a zigzag trace.

Generally in such cases said type of stitching is attained by hand-operating knobs or levers or other particular mechanisms conveniently provided outside the machine; by varying at will the position of those devices during sewing, the

seamstress can obtain, if she is skilful, besides the normal zigzag seam,even other figures, thus creating trueembroideries, the complexity and richness of which are a function of her ability and fancy.

It is an object of the present invention to pro vide a device which if applied to a normal zigzag sewing machine enables it to create automatical 1y even highly complicated embroideries.

Since in all known sewing machines, the zigzag-stitching is obtained by acting upon two different mechanisms one of which is designed to graduate the amplitude of the zigzag movement of the needle, the other is designed to cause the zigzag movement to develop symmetrically either about its middle position or starting from two lateral positions (right-hand and left-hand respectively) towards the middle position, the device in question comprises a ratchet motion,

means for transforming the oscillating movement of said lever (L) into a discontinuous rotary movement of the ratchet wheel, a pair of cams rigidly connected to the latter and two lever systems depending upon the two cams and connected with their free ends respectively to said two mechanisms. I v

In the accompanying drawing there is illustrated merely by way of example one embodiment as follows: Figures 1, 2 and 3 represent respectively in front view and in section along the two planes AA and BB the subject device; Figures 4 and 5 represent in lateral view and in horizontal section along the broken line QC 2. zigzag machine (for instance the machine covered by Italian Patent 363,084) equipped with the device in question. The necessary elements of the known machine are described below to serve as a basis for the present invention.

The body of the machine is composed as conventional by an arm A adapted to be rigidly connected to a base to form a single body supporting the whole. 7 v I v A common drive shaft of the machine carries a helical gear which drives a gear having a vertical 3x15.

The ratio is such that the gear having the vertical axis performs one turn for every two turns of the common drive shaft. The gear carries rigidly an eccentric M, as shown in Fig. 5, which turningwithin a groove provided on the lever L makes this lever oscillate towards the right and towards the left. The lever L is fulcrumed on theaxis I, which is fixed.

The lever L has at its bottom another groove in the shape of an arc of a circle, the axis of which passes through the axis I, and within which there is provided a roller carried by the small connecting rod H, to which the reciprocating movement of the lever L is transmitted.

Another lever P-, fulcrumed with slight friction at Q and controlled from outside by means of the handle R, carries a groove which is turned upward, which is under the groove of the lever L and is substantially normal thereto. With this groove there is engaged a second roller carried on the same axis of the first one mounted on the small connecting rod H in such a manner that by displacing the lever P by means of the handle R it is possible to vary at will the position in which the first roller is engaged in the groove of the lever L until bringing it under the axis I of said lever L.

p In this position the movement transmitted by the lever L to the small connecting rod H is substantially zero while it grows greater as the roller is moved away from the axis I.

The other end of the small connecting rod H is articulated on a pin carried by a small lever F fitted onto a vertical shaft C, to which is thus transmitted the oscillatory movement of amplitude, variable at will, and such as to achieve one complete oscillation for every two turns of the common drive shaft, that is, every two stitches.

The vertical shaft 0 transmits in turn the oscillatory movement to two drag rods, the first of which is pivoted on the same lever F and transmits the lateral movement to the needle bar, which for this purpose is not mounted as usual on the arm A, but on an oscillatable frame.

The second drag rod is placed under the base and is articulated on a lever rigid with the vertical shaft C, and transmits movement to a member supporting a shuttle, which member in turn transmits it to the control shaft of the shuttle. The alternate rotary movement for the shuttle control is transmitted, as in conventional machines, to a shaft, without requiring any addition of special members for the axial oscillatory movement.

in fact, the movement is always transmitted to this shaft by means of a roller or a prismatic 3 piece pivoted on a small lever fitted onto said shaft.

This roller or prismatic piece is to be driven by a fork carried by the rocker and slides within the fork.

This sliding also allows for displacement in axial sense of the shaft provided that the prismatic piece be of sufficient width to be always engaged in the fork.

In this way, the shuttle and the needle red are displaced simultaneously to the right and to the left in such a manner as to make a stitch when they are on the right side and a stitch when they are on the left side; this movement, in coopera' tion with the normal feed motion of the workpiece, forms the so-called zigzag stitch.

The amplitude of the lateral movement is adjustable at will by means of the hand lever R until being reduced to zero at a determined position of said lever. In this case the machine operates like a common central bobbin machine, without any variant in the characteristics of the latter.

However, it is convenient that in this position sewing may be performed completely right-hand as well as completely left-hand or even in the center of the corresponding zigzag seam line. For this purpose, the axis I of the lever L is not fixed, but is supported by a lever S rotatable with slight friction on the axis T and controlled from outside by means of the handle U rigid with the lever S.

If the lever P is in the position of zero zigzag, the end of the link H engaged in the groove of the lever L is as above set forth on the axis I.

The groove of the lever P, which also holds the end of the small connecting rod H engaged, has a shape of circular sector, which, in zero zigzag position has its center on the axis T. In this way, the zigzag movement is zero in any position of the lever S, but varying this position, the small connecting rod H displaces the vertical shaft C thus varying the needle position laterally.

If the lever P is in the maximum zigzag position, the end of the small connecting rod H is about under the axis of the eccentric M, and in this position the movement of the small connecting rod I-I (viz. the zigzag movement) is not infiuenced in practice by the position of the lever S.

Displacing the handle U as desired, one thus attains the purpose of bringing the straight seam to the right side, to the left side or to the center line in respect to the zigzag seam line.

As the drawings clearly show, the device in question, contained in the casing l provided with a tilting cover 2, comprises above all the control rod 3 upon which is fixed, in a position adjustable at will, the small block 4% rigid with the blade 5 designed to actuate the ratchet wheel 6. Upon the axle of said wheel there are fitted the two cams l and 8. The cam 1 acts by way of the roller 9 upon the lever l9 pivoted at I l and connected by means of the stay E2 to the lever l3 pivoted at it; while the second cam 8 acts by way of the roller 55 upon the lever 16, which too is pivoted at i l and connected by way of the stay H to the lever l8 pivoted at [9.

To the free end of the lever 13 there is fixed and adjustable in position by means of the screw 2!, the fork 22 and analogously to the free end of the lever 18 there is mounted, adjustable in position by means of the screw 23, the fork 24; the two forks therefore can be placed respectively in correspondence with the two apertures 25 and 26 provided at the bottom of the casing i 4 or they can be lifted to leave the space of the apertures.

In the example of application according to Figures 4 and 5, the mechanisms for graduating the amplitude of the zigzag movement and for selecting the stitching zone of the needle, are constituted by the mechanism set forth in the zigzag machine according to Italian Patent 363,084 and as explained above the respective control members are constituted by the levers U and R, while the lever L, during the operation of the machine, performs by effect of the action of the eccentric a reciprocating movement oscillating about the axis L.

Now in the device according to the invention the angle-end 3 of the control rod 3 comes through the slit 3 provided in the body of the casing I to engage with the external part of the lever L, against which it is kept adherent by the action of the spring 21, while the

forks

22 and 24 come respectively to engage on the end of the levers R, and U; as a consequence, while the machine is in operation, the oscillating movement of the lever L determines a straight-lined reciprocating movement of the rod 3 and, therefore, by way of the ratchet mechanism 5E, a nonuniform rotary movement of the cams l and 8.

To each of the angular positions assumed by said cams during their movement of discontinuous rotation, there correspond two definite positions of the

forks

22 and 24, and thus of the levers U and R, and thus also of the needle 28, which, therefore, penetrates with each stitch into the zone of cloth as predetermined by the mutual position of the two cams, so as to obtain the desired embroidery figure.

The design as determined by the particular pair of cams selected may be developed over a larger or smaller section of the cloth at will, depending on the length of stitch chosen (which will be obtained by acting in known manner upon the known devices existing in all sewing machines), or depending on the chosen ratio of transmission between the rotation of the crank of the needle bar and the rotation of the ratchet wheel 6. In that way, it is obtained that on slowing down the movement of the cams in respect to that of the moving members of the machine, the embroidery design is developed over a longer section of cloth; and vice versa on varying in the opposed sense the ratio of transmission of the mentioned members.

Said ratio may be easily varied by displacing conveniently the small block 4 along the control rod 3, as according to the position which said small block is made to assume, the number of teeth of the wheel 6 involved with each reciprocating movement of the rod 3 is different and, therefore, the angle is different, by which the wheel 6 turns at each reciprocating movement of the rod 3.

To interchange the cams in order to vary the embroidery design, the knob 29 is unscrewed.

Of course it should be understood that there may be various different embodiments of the device without departing from the scope of the present invention.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, Ideclare that what I claim is:

1. A device for use on sewing machines for zigzag sewing equipped with a mechanism for graduating the amplitude of the zigzag and with a mechanism for the displacement of the stitching zone with respect to the middle position of the needle and with at least one lever adapted for oscillating movement, comprising a ratchet mechanism including a ratchet wheel, means for transforming oscillating movement of the oscillatable lever into a discontinuous rotary movement of the ratchet wheel, a pair of cams rigidly connected to said ratchet wheel and two lever systems actuatable by said two cams and having their free ends connected respectively to said zigzag mechanism.

2. A device as claimed in claim 1, said means for transforming oscillating movement of the oscillatable lever into a discontinuous rotary movement of the ratchet wheel comprising a reciprocably mounted rod, one end of said rod cooperating with said lever under the action of a spring and the other end thereof being fixed to the ratchet wheel actuating mechanism.

3. A device as claimed in claim 2, the ratchet wheel actuating mechanism is supported on said rod slidably and adjustably whereby it can be adjusted in a desired position.

References Cited in the file of this patent FOREIGN PATENTS Number