US3696769A - Basting stitch mechanism for household zigzag sewing machine - Google Patents

Abstract

A zigzag sewing machine equipped with mechanism in which an eccentric is utilized in connection with the shuttle driving mechanism to vary cooperation of the shuttle with the needle for selectively preventing the interlocking of the first and second threads respectively carried by the needle and the shuttle, whereby a skip stitch may be obtained to provide a greatly spaced stitches likely to meet the requirement of basting stitches.

Description

United States Patent Sawada 1 Oct. 10, 1972 [54] BASTING STITCH MECHANISM FOR [56] References Cited HOUSEHOLD ZIGZAG SEWING UNITED T PATENTS MACHINE 3 361 100 1/1968 Bo 112/159 no [721 Invent sawada okazak" Japan 1,411,003 3/1922 De Voe ..112/154 73] Assignee; Aisin seiki Kabushiki Kaisha, 3,490,401 1/ 1970 Hamlett ..1 12/ 159 Kariya, Aichi Pref.,Japa n V Primary Examiner-Patnck D. Lawson [22] Filed: 16, 1970 Att0mey--Pierce, Scheffler & Parker 21 A 1. N 98 632 l 1 pp 57 ABSTRACT A zigzag sewing machine equipped with mechanism in v [30] Foreign Application Pnonty Dam which an eccentric is utilized in connection with the Dec. 23, 1969 Japan ..44/ 1( 3 9 shuttle driving mechanism to vary cooperation of the shuttle with the needle for selectively preventing the [52] US. Cl ..112/159 interlocking of the first and second threads respective- [51] Int. Cl. ..D05b 3/02 y a d y the needle and th shuttl hereby a 53 skip stitch may be obtained to provide a greatly Field of Search ..112/158 R, 159, 154

spaced stitches likely to meet the requirement of basting stitches.

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SHEET 3 0F 4 BASTING STITCH MECHANISM FOR HOUSEHOLD ZIGZAG SEWING MACHINE BACKGROUND OF THE INVENTION mal thread concatenation may be prevented by utilizing various methods such as manipulation of the looper or needle thread or by providing special needles, attachment in the bed of the sewing machine or a mechanism which serves to interrupt the endwise reciprocation of the needle-bar at predetermined intervals.

Even though greatly spaced stitches may be produced for the basting stitches, all of these methods complicate the construction as well as operation of the sewing machine. Additionally, and often more serious, it requires considerable skill properly to set the related sewing machine controls, these being the drawback of the prior art and undesirable to reduce the manufacturing cost of the sewing machine.

Generally speaking, the present invention contemplates the provision of mechanism in which the interruption of the stitch formation is effected by simple, conveniently accessible, and easily adjustable parts, and where such parts are capable of incorporation into sewing machines of conventional type.

SUMMARY OF THE INVENTION The present invention comprises mechanism to inerrupt the cooperation of the loop taker shuttle with the needle at predetermined intervals under the condition that the other sewing machine controls are adjusted for zigzag sewing operation. The interrupting mechanism serves to prevent the hook of the loop taker shuttle from cooperating with the needle, with the hook positioned in front of one of acting positions of the needle but at the back of the other. The mechanism is accompanied by means effective for selectively rendering the mechanism inoperative so that the sewing machine remains in the normal zigzag or straight stitch sewing mode. The mechanism is incorporated into sewing machines of conventional type in which the shuttle alternately makes one-half backward and forward revolutions about an axis substantially perpendicular to an imaginal plane in which lies the zigzag oscillation of the needle.

' The present invention eliminates the disadvantages of the prior art skip-stitch mechanisms briefly outlined above by placing a simple and compact interrupting mechanism within unused space of the sewing machine. According to the present invention, the stitch interruption may be effected by a simple, conveniently accessible, and easily adjustable mechanism being capable .of incorporation into sewing machines of conventional type.

It is an object of this invention to provide an improved stitch formation i nterrupting mechanism for a zigzag sewing machine at predetermined intervals.

It is another object of this invention to provide a stitch formation interrupting mechanism that is manually adjustable to render the mechanism inoperative so that the sewing machine remains in the normal zigzag or straight stitch sewing mode.

Since the mechanism of the present invention is readily applicable to sewing machines of conventional type as above briefly outlined, the zigzag oscillating mechanism which they might have will not specifically be illustrated and set forth here.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a machine embodying certain features of the invention, parts being broken away;

FIG. 2 is an enlarged detailed perspective view of the components particularly showing the shuttle driving parts of the machine illustrated in FIG. 1;

FIG. 3 is the similar view to that of FIG. 2 but it shows the connecting rod and the lever of the bottom shaft in assembled condition;

FIG. 4 is the same view as that of FIG. 3 but it shows an exploded perspective view of the elements;

FIG. 5 is a diagrammatic view showing the relationship between the shuttle and the needle;

FIG. 6a to FIG. 7b are diagramatic showings of the resultant stitches in enlarged scale; and I FIG. 8 is a diagrammatic view showing the adjustment of the lever relative to the crank of the main drive shaft of the sewing machine.

DESCRIPTION OF THE PREFERED EMBODIMENT The present invention is illustrated in the drawing as embodied in a sewing machine having a conventional zigzag mechanism that is herein illustrated and described only insofar as it is believed to be necessary for an understanding of this invention.

With reference to the drawings, FIG. 1, such a sewing machine may include a base 1 having the usual hollow upright bracket 2 extending upwardly therefrom,

the hollow arm 3 extending, in substantially the usual manner, over base 1 to present the usual front bearing upright 4 immediately over needle plate 5 provided base 1. Upright 4 may provide bores or other suitable guides in which may slide presser foot bar 6 and needle bar 7. In arm 3 may be positioned a main drive shaft 8 (shown only in part, and dotted) from which, by suitable mechanism (not shown), reciprocating motion is imparted to needle bar 7. A combined pulley-and-hand wheel 9 is attached to the main drive shaft 8 at the end thereof extending beyond bracket 2, and provides fro association therewith of a belt or other suitable means for driving the machine. Thread-carrying needle 10 receives a single thread from any suitable spool or other source of supply through the necessary tensions and feed pick-ups, which need not be specifically designated here. The needle 10 is reciprocated by the needle bar to pass through a known opening (not shown) in presser foot 11 and known opening in the needle plate 5 to penetrate fabric (not shown) which may have been positioned upon the needle plate. The usual feed action by feed dogs (not shown) may be obtained from eccentrics, operating from main drive shaft 8 through eccentrics l2 and 13 (shown only in part in FIG. 1) to actuate the usual bell cranks (not shown).

Suitably mounted on the under side of base], as for instance, in bearing lugs 14 and 15 is a bottom shaft 16. At the right end of the shaft 16 is fastened an arm or lever 17 which in turn is rotatively connected through connecting rod 18 to crank 19 on the main drive shaft 8. The shaft 16 carries at its left end a segment bevel gear 20 which meshes with another bevel gear 21 carried by shaft 22 perpendicular to the shaft 16 in an imaginary plane substantially parallel to the base 1, as shown in FIG. 2. Atthe front end of the shaft 22 as viewed in FIG. 2 is fastened driver 23 of usual configuration engaging with known loop taker shuttle 24 which is free to rotate within the usual circular race (not shown) one-half back and forward revolutions of about l80 to one complete revolution of the main drive shaft 8-The segment gear 20 is accordingly only provided with enough teeth to rotate the driver one-half revolution of about 180. The needle bar 7 is mounted for reciprocation in needle barframe r holder 25, as indicated by the double arrow a, said frame being in turn mounted for oscillation at right angles to the work feeding direction about a fixed pivot or spindle 26- supported by the frame of the machine, as indicated by the double arrow b in the drawing. Reciprocation of the needle is effected'in a known manner by coupling of the, needle bar 7 with the main drive shaft 8 of the sewing machine via crank 29 and link 27 connected to journal pin 28 affixed to the bar 7 just back of the bar frame 25,.Crank pin 29 is held in fixed eccentric position through member 30 being in turn affixed to another crank pin3l on the counter weight driving crank 26'. The numeral 32 denotes the usual needle thread take up member driven by said other crank pin 31. Linked to the needle bar 25 is one end of control bar 33 whose opposite end is in turn linked to a reciprocating member of zigzag drive mechanism which may have been assembled within the hollow arm 3. The numeral '41 denotes a control lever customarily used in the zigzag drive mechanism for pre-setting the overstitch width. As previously stated, the zigzag drive mechanism need not be specifically. illustrated because it may take any conventional type when applied to the mechanism of the present invention.

With reference to the skip-stitch mechanism of the present invention shown in FIG. 2 to FIG. 8, the mechanism is shown more clearly in enlarged scale. The connecting rod 18 is at its lowermost end connected to .the lever 17 through a pin generally shown by the reference character 34 in FIG. 4. 'The pin 34. is longer than would ordinarily be required. Section 34a of the pin fits the bearing 18a in the connecting-rod 18 and the axially extending section 34b is eccentric with the axis of the section 34a and fits through the bearing 17a in the lever or arm 17 as will be seen in FIG. 4. At the left-hand end of the pin, is carried a small pin 35 firmly fitted in radial hole 34c with both ends slightly extended beyond the periphery of the section 34b, as shown in enlarged view of FIG. 3 and FIG. 4. On the end face of the bearing 17a of the lever 17 is formed two radially opposed notches 17b adapted to receive said small pin 35, thus the notches lock with the section 34b in a given side with respect to the center of the section'34a. A coil spring 36 mounted on the pin 34 is disposed between the bearing of the connecting rod 18 and knob 37. formed at the end of the pin normally to force the pin outwardly, this motion holding the small pin 35 in engagement with the notches 17b. If a displacement of eccentric position of the section 34b is required with respect to the centerof the section 34a, the small pin 35 is disengaged from the notches merely by pushing the knob inwardly to the left in the bearings 18a and 17a; the pin may then be turned by hand, the knob 37 being knurled to provide a better grip. When the leftward pushing is released, the spring 36 immediately forces the small pin 35 backinto engagement, thus relocking the setting. The illustration in FIG. 3 shows the small pin 35 in one of its engaged positions.

. In FIG. 5, the numeral 38 denotes the shuttle of known and conventional type ordinarily used in the popular household sewing machines, which shuttle receives a bobbin or spool (not shown) having a second thread wrapped thereon. The shuttle is free to rotate on an internal surface of the known circular race shown by dot-and-dash line and by numeral 39. The center of the race is substantially opposite a stud 40 secured to and extending from the center point of the, shuttle and aligned with the axis of the driving shaft 22 (FIG. 2). Rotatively and removably mounted on thestud 40 is the spool in the sewing operation to supply the second thread for interlocking with the first thread carried by the needle. In FIG. 5, the shuttle is shown in its rest position just prior to start up of rotation. in the clockwise direction to take the loop having been formed inthe first thread carried and engaged by the eye of the needle. The shuttle first rotates in the clockwise direction about one-half revolution of and then rotates in the reverse direction the same angular amount, returning to its original position shown in heavy line in FIG. 5. The shuttle alternately repeats such forward and reverse rotations per one .revolution of 360 of the main drive shaft of the machine. The numerals 10a and 10b respectively denotes lowermost positions of the needle having reached extreme ends of its downward travel respectively in two successive different zigzag sewing cycles. When the needle 10 carries thread engaged in its eye in usual manner through the fabric, and then is started on retraction, the slack thus produced in the thread forms a loop. The hook 38a of the shuttle 38, as the shuttle rotates to the clockwise direction as viewed in FIG. 5, is presentedimmediately beside the eye (not shown) of the needle 10 and will engage within the loop thus produced.

At this stage of the operation, the shuttle receiving the second thread bobbin, passes through the loop and on retraction of the needle, the loop is drawn through the fabric, where the usual interlock of the second thread with the first thread follows in producing the usual lockstitches. I

As will be seen from the preceding, the hook 38a can catch the loop in every sewing cycle regardless of whether the needle position is at 10a or 10b because the book may move past the eye in every sewing cycle. It'will be further noted that if the hook starts its loop taking motion to the right from the position 38a, after the position 10a but before 10b, the stitch formation at the position 10a is prevented. This is very important in obtaining the resultant stitches required.

As will be explained in detail below when the pin 34 is so adjusted by hand that the eccentric section 34b is displaced upwardly and held as shown in dotted line by the reference character 34b in FIG. 8, sewing machine is placed in the skip-stitch mode, but when the section 34b is positioned in the lowermost position as shown in heavy line by the the reference character 34b the sewing machine remains in the conventional sewing mode.

By this adjustment, the oscillation of the lever 17 is varied as to its position from are B to are A as shown in FIG. 8.

Turning now to the operation of the presently disclosed invention, when the pin 34 is manually so adjusted and held that the hook 38a accordingly starts its loop taking motion before the needles position a, the sewing machine operates in the conventional mannersewing zigzag stitches depending upon the setting of the other sewing machine controls. When, however, the pin 34 is so adjusted that it rotates onehalf a revolution and section 34b is displaced to and maintained at the position represented by the reference character 34b the hook 38a advances its starting position to the position 38a as shown in dotted lines in FIG. 5. The stitch formation is thus prevented at the needles position 10a, that is, in every alternate cycle'of sewing straight stitches greatly spaced result even though the other sewing machine controls remain in zigzag sewing positions. The resultant stitch interval is about twice that of the normal straight or zigzag stitches as will be readily seen in FIG. 6b in contrast to FIG. 6a. In FIG. 6a and FIG. 6b, the small holes represent the needle holes in enlarged scale and the heavy line represents the thread laid on the surface of the fabric. In the stitches resulting from the skip stitch operation FIG. 6b, the needle holes in the left column are left disconnected with the sewing thread and the required greatly spaced straight stitches thus result.

When the other sewing machine controls are adjusted for the blind stitch operation, while the pin 34 is maintained at the same skip stitch position, further greatly spaced straight stitches may result as viewed in FIG. 7a and FIG. 7b. In the stitches of FIG. 7b, the distance between any two neighboring stitches is four times as long as the distance of the normal blind stitches in FIG. 7a. The desired straight stitches, greatly spaced, will thus be obtained for the basting stitches.

What is claimed is:

l. A sewing machine comprising a needle bar frame, a needle bar slidably carried thereby, a needle mounted on said needle bar, means for reciprocating said needle bar vertically, means for oscillating said needle bar frame between two lateral positions at right angles to the work feeding direction, a shuttle means, means for oscillating said shuttle means about its axis between two limits in a plane parallel to the direction of oscillations of said needle bar frame to normally cooperate with said needle in each lateral position to form zigzag stitches and means for selectively moving the limits of oscillatory movement of said oscillatable shuttle about the axis thereof so that said shuttle will not pass said needle when at one of its lateral positions whereby a basting stitch will be formed by said needle and said shuttle means at the other lateral position.

2. A sewing machine as claimed in claim 1 wherein said means for moving the limits of oscillatory movement of said oscillatable shuttle includes a connecting rod mounted at one end to a crank provided on the main drive shaft of the sewing machine, rotatably adjustable pin means mounted at the other end of said connecting rod, a lever connected at one end to said adjustable pin means for. oscillation thereby, a shaft oscillatable by said lever, said shuttle means being operal connecgted to said oscillatable shaft, said rotata y ad usta le pm means having an eccentric portion connected to said lever and means for selectively rotating said pin means so that the eccentric portion of said pin means will change the limits of oscillation of said shaft.

3. A sewing machine as claimed in claim 2 wherein said means for selectively rotating said pin means includes means for locking said pin means in a selected position.

4. A sewing machine as claimed in claim 3 wherein said adjustable pin means includes means for manually operating said locking means and for adjusting said pin means to the desired position.

Claims (4)

1. A sewing machine comprising a needle bar frame, a needle bar slidably carried thereby, a needle mounted on said needle bar, means for reciprocating said needle bar vertically, means for oscillating said needle bar frame between two lateral positions at right angles to the work feeding direction, a shuttle means, means for oscillating said shuttle means about its axis between two limits in a plane parallel to the direction of oscillations of said needle bar frame to normally cooperate with said needle in each lateral position to form zigzag stitches and means for selectively moving the limits of oscillatory movement of said oscillatable shuttle about the axis thereof so that said shuttle will not pass said needle when at one of its lateral positions whereby a basting stitch will be formed by said needle and said shuttle means at the other lateral position.

2. A sewing machine as claimed in claim 1 wherein said means for moving the limits of oscillatory movement of said oscillatable shuttle includes a connecting rod mounted at one end to a crank provided on the main drive shaft of the sewing machine, rotatably adjustable pin means mounted at the other end of said connecting rod, a lever connected at one end to said adjustable pin means for oscillation thereby, a shaft oscillatable by said lever, said shuttle means being operably connected to said oscillatable shaft, said rotatably adjustable pin means having an eccentric portion connected to said lever and means for selectively rotating said pin means so that the eccentric portion of said pin means will change the limits of oscillation of said shaft.

3. A sewing machine as claimed in claim 2 wherein said means for selectively rotating said pin means includes means for locking said pin means in a selected position.

4. A sewing machine as claimed in claim 3 wherein said adjustable pin means includes means for manually operating said locking means and for adjusting said pin means to the desired position.

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