US3468270A - Sewing machine for straight or zigzag sewing - Google Patents

Description

Sept. 23, 1969 A. MORO SEWING MACHINE FOR STRAIGHT OR ZIGZAG SEWING 2 Sheets-Sheet 1 Filed Feb.

F/GSD Attorneys I Sept. 23, 1969 MORO 3,468,270

SEWING MACHINE FOR STRAIGHT 0R ZIGZAG SEWING Filed Feb. 27, 1967 2 SheetsSheet 2 I nvenlor fl/vro/v/a Maea Bykwy JMAJ Attorneys United States Patent ice 3,468,270 SEWING MACHINE FOR STRAIGHT 0R ZIGZAG SEWING Antonio Moro, Milan, Italy, assignor to Soc. per Azioni Fratelli Borletti. Milan. Italy, an Italian company Filed Feb. 27, 1967, Ser. No. 618,830 Claims priority, application Italy, Mar. 1, 1966, 15,048/ 66 Int. Cl. Db 3/02 US. Cl. 112158 3 Claims ABSTRACT OF THE DISCLOSURE A sewing machine for domestic use, of the type adapted to produce straight zigzag stitching and having an oscillating pendulum, a needle bar slidably mounted in the pendulum, a cam for imparting the oscillation, a transmission rod associated at one end with the pendulum and at the other end with an oscillating lever driven by the cam to reciprocate the transmission rod, is improved in two respects:

(1) An operating knob and an eccentric pin fast therewith shift the axis of oscillation of the lever so as to stitch to the right or to the left or on center or in any other intermediate position; and

(2) Another operating knob and eccentric pin fast therewith transversely shift the transmission rod so that its driven end moves toward or away from the axis of the oscillating lever thereby to change the amplitude of pendulum oscillation.

The object of the present invention is a sewing machine of the type adapted to carry out straight or zigzag stitching, this machine being for domestic use and cheap to make.

In the present state of the art, sewing machines which carry out straight or zigzag sewing at choice and enable the start of the stitching to be fixed in the centre, on the right or on the left of the working range of the needle are known and widely distributed. There are many kinds of devices which perform this function and the improvements which are being studied today aim essentially at making the machine simpler and more economical without, however, foregoing a high level of functionality or the widest sewing possibilities of the machine.

The aim of the present invention is precisely to produce a machine which, in addition to normal straight sewing, will also carry out zigzag sewing by the use of mechanisms which are simply constructed and easy to apply and also of control elements adapted to be actuated from outside the machine and which are practical to use and can be used instantaneously.

The sewing machine according to the present invention is more precisely of the type comprising a needle bar slidable in an oscillating pendulum, a cam controlling the oscillation and a transmission rod associated directly at one end with the said pendulum and co-operating indirectly at the other end with the said cam to transmit the oscillation produced by the latter to the said pendulum; the machine is characterised substantially in that an oscillating lever with an arm having .an action of adjustable amplitude is interposed between the profile of the said cam and that end of the transmission rod which co-operates with the cam.

3,468,270 Patented Sept. 23, 1969 Preferably, the said oscillating lever is pivoted at one end at a substantially fixed point of the machine and is kept in contact at the other end with the cam controlling the oscillation, the end of the said transmission rod being kept in contact in turn with the said oscillating lever, with the possibility of displacement along the same.

The following description, however, is intended to explain the structure and operation of the invention better on the basis of the accompanying drawings, which relate to a preferred constructional form and in which:

FIG. 1 is a longitudinal section of the arm of the machine, in the vertical plane of the device according to the invention;

FIG. 2 is a diagrammatic plan view of the said device;

FIG. 3a shows in section the knob and eccentric pin for controlling the starting position of the stitching;

FIG. 3b is a front view of the said knob;

FIGS. 4a, 4b and 4c are a longitudinal section and a cross-section of the assembly of the knob adjusting the amplitude of the zigzag and a front view of the said knob;

FIGS. 5:: and 5b show, partly in section, the control for the engagement and disengagement of the zigzag device, in its two operative positions;

FIG. 6 shows a detail of the mounting of the gear with the cam and which is controlled by the gear fixed to the main shaft;

FIGS. 7a, 7b and show various working positions of the lever arm controlling the zigzag.

The shaft 1 (FIGS. 1, 2) controls in known manner, in the front part 2 of the machine, the vertical movement of the needle bar and the thread take-up lever, and, in the rear part 3, the elements which actuate the shuttle or the rotating hook, according to the type of machine, and the material feeding device, all of which are of known type; mounted on the shaft 1 is the helical gear 4 meshing with the gear 5 with a transmission ratio of 2:1, so that the gear 5 makes one revolution for every two revolutions of the gear 4. The gear 5 is mounted rotatably on the pin or pivot 6 (FIG. 6) projecting from a stationary body 7 having a hole normal to the axis of the pin 6; by means of the said hole, the body 7 is mounted on the vertical pin 8 fixed to the frame and is clamped by means of the screw 9 after the optimum position for meshing of the gears 4 and 5 has been found.

The cam 10 of the three-lobed form is integral with the gear 5 and therefore performs one revolution for every two revolutions of the main shaft 1.

A pin or pivot 11 (FIG. 3a) parallel to the pin 6 is mounted rotatably in the hole 13 in the wall 14 of the frame arm of the machine; inside the machine, the pin 11 is extended in a pin 12 having its axis eccentric with respect to the axis of the pin 11.

Mounted for oscillation on the eccentric pin 12 is the lever arm 15, which bears on the surface of the cam 10 through a convex zone 16 (FIG. 1) shaped with a small radius and parallel to the pin 12. During the rotation of the cam, the lever arm 15 performs angular oscillations about the pin 12 (see FIG. 7), passing alternately into the positions 17 and 18, with an angular movement corresponding to the difference between the angle a (FIG. 7a) and the angle B (FIG. 7b).

Under these conditions, the rod 19 (FIG. 1), which is pivoted at one end to the pendulum 20 carrying the needle bar and oscillating through the medium of the hinge 20', and which keeps its other pointed end 22in contact with the surface 23 of the lever arm 15 through the action of a spring 21, will be subjected to an axial displacement, corresponding to the oscillation of the lever arm 15, in the directions of the arrows 24 (FIG. 1). This displacement or movement is of zero value when the point 22 is at the top, in a position coinciding substantially with the axis of the pin 12 (FIG. 7b), and has a maximum value when the point 22 is located almost in correspondence with the point of contact between the zone 16 and the cam 10 (FIG. 70). The movements of the rod 19 are transferred proportionately to the needle bar, which latter will perform corresponding lateral excursions, with an amplitude from zero to a maximum, for the formation of the zigzag stitch.

If the end 22 of the rod 19 remains at the top, in correspondence with the axis of the pin 12, the needle does not oscillate transversely and the stitching is straight.

It is possible to rotate the pin 11 by means of the knob fast therewith and obtain a shifting of the eccentric pin 12, for example to the right (FIG. 7a); in this way, there is also obtained a shifting of the needle to the right and, as long as the point 22 remains in coincidence with the axis of the eccentric 12, straight stitching will be obtained, all and always on the right of the working range. As has been said above, by shifting the point 22 along the surface 23, transverse movement of the needle for the formation of the zigzag, with increasing amplitude, is obtained; the characteristic of the zigzag stitches obtained in this way is that they always start from a position on the right, or on the right-hand margin of the working range, whatever their amplitude.

In symmetrical fashion, if the pin 12 is shifted completely to the left, into the position shown in FIG. 7c, straight stitching on the left and zigzag stitching in which the stitches always start from the left-hand margin of the working range will be obtained. Similarly, for intermediate positions of the pin 12, intermediate sewing positions will be obtained.

The extreme simplicity of construction and operation of the device according to the invention is obvious, this being achieved by inserting a simple lever arm 15 between the control cam 10 and the transmission rod 19 connected to the pendulum of the needle bar.

The shifting of the point 22 of the rod 19 along the surface 23 is controlled by means of the knob 26 (FIGS. 2 and 4a), which is fast with the pin 27 mounted rotata'bly in the bush 27 formed by the wall 14.

Keyed on the pin 27 at that end which is remote from the knob 26 and inside the wall 14 is the arm 28 (FIG. 4b) to which the pivot 29 is fixed eccentrically with respect to the axis of the pin 27. Mounted on the pivot 29 is one end of the link 30 carrying at the other end the pivot 31 (FIG. 4a) engaging in a hole in the rod 19. Upon turning the knob 26, the pivot 29 performs an excursion in the vertical direction carrying the link 30, and therefore the rod 19, with it. The screws 28', which are adjustable in suitable seats at the ends of the arm 28, have an arresting function, so that the knob 26 can be made to turn only through a given angle corresponding to the maxi-mum excursion of the point 22, substantially between the axis of the pin 12 and the point of contact between the surface 16 and the cam 10.

The end 32 of the rod 19 is pivoted to the pendulum 20 (FIG. 1) at 32 by means of a pin 33 (FIG. 2) provided with an eccentric and which can be clamped by means of the set screw 34; this connection enables the pendulum of the needle bar to be set in the correct position with respect to the cam 10 by simply turning the pin 33 until the needle is centered over the hole in the needle plate and then locking it by means of the set screw 34. As has been said, the spring 21 holds the point 22 of the rod 19 in contact with the surface 23 of the lever arm 15, while a spring 35 holds the free end of the lever 15 in contact with the cam 10.

When the machine is to carry out only straight stitching, it is useful to exclude operation of the zigzag stitching device completely, so as not to subject the cam 10 to working unnecessarily.

To this end, the lever 36 (FIGURES 5a, b) is provided, this being pivoted on the end 37 of the pin 6 and moreover having a short arm 38 terminating in a flat transverse edge; when the lever 36 is in the righthand position 39 illustrated in FIG. 5a, the lever 15 can oscillate freely, controlled by the cam 10, so as to produce the zigzag stitch. On the other hand, when the lever 36 is shifted into the left-hand position indicated in FIG. 5b, the end of the arm 38 is disposed so that the stud 38 fast with the lever 15 bears on the said end so as to hold the lever 15, and more exactly the zone 16, out of engagement with the cam 10. The latter then rotates idly, avoiding unnecessary wear, and the zigzag stitching device remains inoperative.

It is then possible to make straight stitching or seams which are central, on the right or on the left, according to the angular position of the knob 25, it being possible to check this position by bringing one of the marks 40 into line with the fixed index 41 (FIG. 3b)

The amplitude of the zigzag, on the other hand, can be read on the graduated scale 42 (FIG. 40) on the knob 26 with respect to the fixed index 43.

With the device according to the present invention, which is of extremely simple construction and assembled inside the arm of the machine, and by operating separately or in combination the knobs 25 and 26 and the lever 36, it is possible to obtain with the maximum ease and simplicity, at will and according to the ability of the user, straight stitching on the right, on the left or in the centre; zigzag stitching of an amplitude adjustable from zero to a maximum, with its origin in the centre, on the right or on the left; invisible stitching, buttonholes, various ornamental stitches, embroidery, mending, attachment of buttons and other needlework.

It is to be understood, however, that other practical constructional forms of the present invention may be different from that described without thereby departing from the scope of the said invention.

What I claim is:

1. In a sewing machine for domestic use, of the type adapted to produce straight or zigzag stitching and comprising an oscillating pendulum, a needle bar slidably mounted in said oscillating pendulum, a cam for imparting said oscillation, a transmission rod associated at a first end directly with said pendulum, and an oscillating lever cooperating on one side with said cam and on the other side with the second end of said transmission rod for transmitting the oscillation imparted by the cam to the needle bar; the improvement comprising a knob and an eccentric pin fast therewith, the knob being accessible to be operated from outside the machine, said oscillating lever being pivotally mounted on said eccentric pin, the operation of said knob and eccentric pin providing a displacement of the axis of oscillation of said lever in a direction substantially parallel to the direction of action of said cam.

2. Apparatus as claimed in claim 1, and a second knob and an eccentric pin fast therewith, said second knob being accessible to the operator from outside the machine, and means interconnecting said eccentric pin and said transmission rod to shift the transmission rod laterally of the direction of oscillation of the transmission rod and along said lever thereby to change the distance between said second end of the transmission rod and said axis of oscillation of said lever thereby to change the amplitude of reciprocation of said transmission rod.

3. In a sewing machine for domestic use, of the type adapted to produce straight or zigzag stitching and comprising an oscillating pendulum, a needle bar slidably mounted in said oscillating pendulum, a cam for imparting said oscillation, a transmission rod associated at a first end directly with said pendulum, and an oscillating lever cooperating on one side with said cam and on the other side with the second end of said transmission rod for transmitting the oscillation imparted by the cam to the needle bar; the improvement comprising a knob and an eccentric pin fast therewith, said knob being accessible to the operator from outside the machine, and means interconnecting said eccentric pin and said transmission rod to shift the transmission rod laterally of the direction of the transmission rod and the axis of oscillation of said lever thereby to change the amplitude of reciprocation of said transmission rod.

References Cited UNITED STATES PATENTS of oscillation of the transmission rod and along said lever 10 RICHARD J. SCANLAN, JR., Primary Examiner thereby to change the distance between said second end

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