US3515082A - Shuttle race cover - Google Patents

Description

June 2, 1970 5. J. LAMLETT SHUTTLE RACE COVER Filed March 15, 1968 I N VENT OR.

s/onla'y J f/fl/WZETT M 3 m M a p M P A W. M m WW M m If}? 5 Mweuvy United States Patent U.S. Cl. 112-158 9 Claims ABSTRACT OF THE DISCLOSURE A zig-zag sewing machine of the front-facing bobbin type is arranged to produce intermittent locked stitches resulting in a stitch length greater than that determined by the feed of the machine. The shuttle race cover is provided with a deflector which prevents formation of a lock stitch in one needle position by deflecting the needle thread loop out of the path of the shuttle hook. In this needle position no lock stitches are formed while in the other needle position normal stitches are formed so that the stitch length can be controlled by proportioning the stitch formation between the two needle positions.

The present invention relates generally to sewing machines, and more particularly to household zig-zag sewing machines of the type in which the loop forming mechanism oscillates about a horizontal axis perpendicular to the plane of zig-zag movement and in line with the direction of feed of the material through the machine. In machines of this type, commonly called the front facing bobbin type, the loop forming mechanism is fixed with respect to the frame of the machine, and the shuttle hook rotates or oscillates through a curved path of movement parallel to but spaced a slight distance from the plane of the needle in its zig-zag movement, so as to pick up the loop formed from the needle thread at different points along the arc of movement, depending upon the needle position.

. It has been recognized as desirable to have a machine which can produce temporary stitches which may easily be removed and which can replace manual basting for holding fabric temporarily in position for fitting purposes. However, the household or domestic type sewing machine is not normally arranged to provide stitches of sufficient length to allow easy removal in the manner of hand sewn basting stitches.

One arrangement which produces a temporary stitch in sewing machines is the chain stitch which is not permanent, and which upon a pull of the thread will easily unravel. This stitch has the disadvantage that it usually requires either a special machine or an expensive alteration of an existing machine for its production, and because of the fact that it must be sewn Within the usual ranges of stitch length produced by the sewing machine, produces an excessive number of needle holes in the fabric which, with many types of fabric, will remain visible after the thread has been removed.

In the present inventors co-pending application, Ser. No. 668,886, filed Sept. 19, 1967, it was recognized that a temporary or basting type stitch can be produced by a zig-zag lock stitch machine in which the zig-zag pattern is that of a blind hem stitch. The loop forming mechanism of the side-facing type is controlled so that only occasional locked stitches are formed, and for a majority of the cycles of the machine, the shuttle hook is prevented from engaging the needle thread loop, which is then pulled back through the fabric and no stitch is formed. As a result, depending upon the ratio between the two needle positions of the blind hem stitch cam, a stitch is formed with a length corresponding to this ratio times the stitch length as set by the fabric feeding mechanism. This ratio may be between 6 and 12, and therefore represents a lock stitch formed with the stitch length between 6 and 12 times the stitch length of the fabric feed.

The present invention has its principal object the provision of an arrangement in a front facing bobbin type zig-zag sewing machine of producing intermittently locked stitches by selectively controlling the formation of locked stitches so that locked stitches are formed only when the needle is in one needle position and no stitches are formed at another needle position.

Another object of this invention is to provide in a zigzag sewing machine of the front facing bobbin type an arrangement for producing stitches as set forth in the preceding object which does not interfere with the operation of the sewing machine in the formation of normal straight stitches.

Still another object of this invention is to provide in a zig-zag sewing machine of the front facing bobbin type as set forth in the preceding objects a shuttle race cover which is modified so as to provide in one needle position a deflector for holding the needle thread loop out of a position where it can be engaged by the shuttle hook.

Still another object of this invention is to provide in a zig-zag sewing machine of the front facing bobbin type a shuttle race cover for accomplishing the preceding objects which is readily interchangeable by the sewing machine operator with a normal shuttle race cover which permits the full variety of pattern stitches for the machine.

A still further object of the invention is to provide for a zig-zag sewing machine of the front facing bobbin type a shuttle race cover which can accomplish the preceding objects which is readily adaptable to existing machines without change or modification other than the substitution of the shuttle race cover of this invention for the prior shuttle race cover.

Briefly, the foregoing objects and advantages are accomplished according to the preferred embodiment of this invention by providing a modified construction for the shuttle race cover at the upper portion thereof, which in a typical form has a separate attached thread guide for generally confining the needle thread loop. This guide is arranged so that in one needle position it provides a deflector extending in back of the needle above the shuttle hook. In addition, a small deflecting plate may be mounted below the thread guide to extend vertically between the needle and the path of the shuttle hook. As the eye moves downward past the thread guide, the deflector plate moves the thread loop forward away from the path of the shuttle hook, so that this hook is unable to engage the thread loop to form the locked stitch, with the result that with the upward movement of the needle the loop is pulled back outward through the fabric. The arrangement of the thread guide plate at the other needle position is normal and guides the needle thread loop into a position to insure engagement with the shuttle hook to form locked stitches in that position. Thus, by providing a pattern for the zig-zag movement of the needle so that a large number of needle reciprocations occur at one position, locked stitches will be formed only at the occasional movement of the needle to the other position.

Further features and advantages of the invention will readily become apparent to those skilled in the art upon a study of the following detailed description of the preferred and other embodiments of this invention as illustrated in the drawings in which:

FIG. 1 is a front elevational view of a sewing machine with parts broken away to show the front facing bobbin or loop taking mechanism;

FIG. 2 is a top plan view of a shuttle race cover and attached thread guide plate according to the preferred embodiment of this invention;

FIG. 3 is a fragmentary perspetive view of the bottom surface of the thread guide plate of FIG. 2;

FIG. 4 is a fragmentary cross-sectional view taken on line 4-4 of FIG. 2;

FIG. 5 is a fragmentary cross-sectional view taken on line 55 of FIG. 2; and

FIG. 6 is a fragmentary plan view of a thread guide plate according to another embodiment of this invention.

Referring now to the drawings in greater detail, FIG. 1 shows a front elevational view of a typical zig-zag sewing machine of the front facing bobbin type. In general, the machine has a bed plate 10 from one side of which rises a hollow standard 11. A cross arm 12 extends horizontally from the standard 11 and terminates at the other end in a head portion 14 on which is mounted a reciprocating needle bar 15 supporting a needle 16. The needle 16 passes through a presser foot 17 in a normal manner, and it will be understood that the needle bar 15 is oscillated laterally in the plane of the figure by a suitable zig-zag mechanism, which may be of any well-known type. Since the zigzag mechanism for shifting the position of the needle bar 15 in itself forms no part of the present invention, it will not be described in greater detail hereinafter. However, it may be noted that in accordance with a typical construction of this type, the machine is equipped with a width control 19 for regulating the width of the zigzag movement, as well as a needle position control 21 and a stitch length control 22 to regulate the stroke of movement of the feed dogs (not shown).

As shown in FIG. 1, the bed plate 10 has been broken away to display the front facing bobbin mechanism. The feed dogs for controlling the movement of the cloth are not illustrated, nor is the shuttle driving mechanism, which may be any usual type, utilizing either a bevel gear drive or a crank and linkage arrangement. This entire loop taking mechanism includes a shuttle housing 24 which is fixedly mounted in the bed plate 10 below the upper surface thereof and defines a circular raceway within which are mounted the shuttle body 26 and the shuttle driver 27,

The race in which the shuttle body 26 is mounted for rotary movement is closed off on the front face by means of a shuttle race cover 30 which is held in place on the shuttle housing 24 by suitable clamps 31 and 32. The bobbin case 34 containing the bobbin and bobbin thread is mounted on the shuttle housing 24 and has a projecting arm 35 to prevent rotary movement of the bobbin case.

According to the present invention, the shuttle race cover 30 has a modified construction and is interchangeable with the normal shuttle race cover used for normal sewing. The shuttle race cover of this invention is shown in greater detail in FIGS. 2 and 3 where the cover 30 is provided with a generally radially extending Wall portion 37 defining a central opening which allows access to the bobbin case 34 for removal and replacement thereof without removing the shuttle race cover itself. This radial wall 37 is provided with a notch 38 to receive the bobbin case arm 35 to positively restrain the bobbin case against rotary movement. The shuttle race cover also has around most of its periphery an axial flange 40 which is interrupted at 41 to define a gap in the upper portion on either side of the space through which the needle 16 passes during stitch forming.

The gap 41 is covered over by a thread guide plate 44 which is secured to the outer surface of the shuttle race cover 30 by means of screws 45 and 46. As seen most clearly in FIG. 2, the thread guide plate 44 extends generally flush with the front face of the shuttle race cover and has a rear surface 47 projecting beyond the axial flange 40. This thread guide plate 44 as formed for normal stitching, generally has an enlarged notch open toward the back giving clearance all around the needle in both of the extreme needle positions. However, according to the present invention, the thread guide plate provides a deflector behind the needle in one needle position to hold the needle thread loop out of the path of the shuttle hook. In the preferred embodiment the thread guide plate 44 is shaped to have a relatively narrow and deep notch 48 positioned at the left needle position, and accordingly this notch 48 has a left side 49 and an end 50 and right side 51 spaced to give proper clearance around the needle when it is in the left needle position to control the needle thread and prevent the loop from getting out of the desired position. It will be understood that the notch 48 is open toward the rear because it is in this direction that the needle thread loop is deflected to be picked up by the hook on the shuttle body 26.

To provide the deflector at the other needle position, the thread guide plate 44 has a circular hole 53 at the right needle position, and it will be seen that this circular hole 53 is spaced from the notch 48 by a solid web portion 54. The hole 53 is located to be generally co-axial with the needle path and has a diameter sufficiently great to give clearance around the needle, and it will be noted that the front edge of the circular hole 53 is gen erally tangent to a line formed by the end 50 of notch 48.

It will be seen from this arrangement that the machine can only be operated with the needle in either the right or the left needle positions so that the needle passes through either the circular hole 53 or notch 48. This requires either that the zig-zag width be set to zero and the needle position set at either the right or left position, or the needle may be in any of the three normal positions, if the zigzag width is set at maximum so that the needle moves into either of the extreme left and right needle positions in alignment with notch 48 and hole 53.

Although the hole 53 is located and shaped to prevent full ballooning of the needle thread loop, the deflection may be aided if necessary by means of a deflector plate 56 which is held in position clamped between the thread guide plate 44 and the shuttle race cover 30 by means of the right screw 46. This deflector plate 56 extends adjacent to the hole 53 where it has a depending portion 57 and a lip 59 bent along the fold line indicated at 60. By anchoring the deflector plate 56 by only the one screw, it may be adjusted in position to the proper location as described hereinafter.

The operation of the shuttle race cover of this invention is seen more clearly in FIGS. 4 and 5. As shown therein, the shuttle body 26 has a pointed hook 62 which normally engages the open loop of the needle thread 64 to form the usual lock stitch. When the needle 16 passes in the left needle position, through notch 48, the needle thread 64 will balloon out because it is caught in the fabric in the manner shown in FIG. 5 so that the shuttle hook 62 can pass through the loop so that the loop passes around the thread carried by the bobbin in bobbin case 34.

However, when the needle is in the right needle position, it passes through the circular hole 53 adjacent the depending portion 57 of deflector plate 56. This causes the needle thread 64 to be deflected inwardly away from the shuttle hook 62 which then passes behind the depending portion 57 which thereby positively provides a shield between the needle thread loop and the shuttle hook 62 to prevent stitch formation. Thus, if the needle thread is not looped around the bobbin thread, the takeup arm on the machine will pull the needle thread back up through the cloth and no stitch will be formed.

The mounting of the deflector plate 56 allows precise adjustment because of the close spacing between the needle 16 and the shuttle hook 62. This deflector plate 56 must fit within this space, and generally it is located so that the shuttle book 62 passes behind the deflector plate with a minimum of clearance. The bent lip 59 provides a protective feature at this point in the event that the hook has excessive clearance or thedeflector plate is improperly located. If such were the case, the shuttle hook 62 would engage the bent lip 59 and this would either stop the machine without damage or cause the deflector plate 56 to be rotated about the screw 46 until the hook 62 could pass behind the depending portion 57.

From the foregoing, it will be seen that whenever the needle is in the left needle position and passes through the notch 48, a lock stitch Mu'll be formed, while Whenever the needle is in the right-hand position and passes through the circular hole '53, no lock stitch will be formed and the needle thread will be brought back up to the upper surface of the fabric.

If the machine is sewing an ordinary zig-zag pattern in which it moves alternately between the left and right needle positions, the overall effect would be that of forming a locked stitch on every other reciprocation of the needle, and this would provide a stitch length that is effectively twice the stitch length determined by the motion of the fed dogs, and as set by the stitch length control 22. However, the invention can be more advantageously applied by using a pattern such as a blind hem stitch in which a series of, for example, four to twelve consecutive stitches are taken with the needle in the right needle position, followed by a single reciprocation of the needle at the left needle position. In such case, since no stitches are formed at the right needle position, and only a single stitch at the left needle position, the effect will be that of creating an effective stitch length greater than that set by the stitch lengh control 22 by a multiple of the ratio of the blind hem stitch control cam. However, regardless of the pattern of movement of the needle bar guide, as long as the shuttle race cover is in place, no stitches can be formed at the right needle position, while stitches will be formed in the normal manner at the left needle position, and for normal sewing the shuttle race cover of this invention must be removed and replaced by the normal unit.

Although the foregoing arrangement provides positive prevention of the formation of stitches at the right needle position, it does have the disadvantage that it may cause needle breakage if inadvertently the zig-zag width control is shifted to less than maximum, or the needle position control is shifted to the center position, since there is then a liklihood that the needle will strike the web 54 between the circular hole 53 and notch 48. An alternative arrangement which does not have this disadvantage is shown generally in FIG. 6, where a modified thread guide plate 44a is otherwise formed in the same manner and mounted in the same manner as thread guide plate 44. In this case, the thread guide plate 44a has a generally L-shaped opening 65 formed by a deflector tab 63 extending behind the needle at the right needle position to deflect the needle thread loop forward and away from the shuttle hook. The opening 65 is defined by a left side 66 and front side 68 which are generally in the same location as the left and front sides 49 and 50 of notch 48. The front side 68 extends across the right needle position where it terminates in a right side 69. The deflector tab '63 extends toward the left beyond the right side 69 to terminate in an end portion 67 adjacent the center needle position. This tab 63 has a deflector edge 70 extending parallel to the front edge 68 between the right side 69' and the tab end 67. The deflector tab 63 may be used in combination with the deflector plate 56 which may be constructed in the same manner as in the embodiment of FIGS. 2 and 3. However, depending upon the structure of the loop forming mechanism, the deflector tab 63 may extend lower or closer to the shuttle hook in which case the edge 70 may provide positive deflection without the use of the deflector late 56.

It is understood that the deflector tab 63 may be an integral part of thread guide 44 or it may be in the form of a separate piece of metal carried by the shuttle race cover either in a fixed position or else movable into and out of the operable position shown in FIG. 6'.

With this arrangement, the machine may be operated with the needle in all needle positions without danger of needle breakage and in the left needle position a stitch will always be formed, and in the right needle position no stitch will be formed. However, it is recognized that in the event the machine is operated near the center needle position, or only slightly to the right of that position, positive control over the needle thread loop may not be positively maintained and in this zone lock stitches may or may not be formed, depending upon whether the needle thread loop is deflected from the path of the shuttle hook 62.

The foregoing description applies to a sewing machine in which the blind hem stitch pattern is arranged for use with the garment extending toward the left of the sewing machine so that the majority of stitches are made in the right needle position which, for the formation of basting stitches,,is chosen to be the needle position at which stitch formation is prevented. However, in the case of other types of sewing machines in which the formation of the blind hem stitch is reversed with the majority of stitches being formed in the left needle position, the deflector structure as described in any of the embodiments may be reversed so that stitch formation is allowed only in the right needle position and prevented in the left needle position.

Although several embodiments of this invention have been shown in the drawings and described in detail, it is recognized that various other modifications and re-arrangements of the invention will readily become apparent to those skilled in the art and will not depart from the scope of the invention as defined in the claims.

What is claimed is:

1. A sewing machine having a frame including a bed plate and a head structure above the bed plate, a needle bar guide mounted on said head for lateral swinging movement between left and right needle positions, a needle carried by said needle bar guide for vertical reciprocating movement to and from said bed plate, a loop forming mechanism on said sewing machine below said bed plate; said loop formingv mechanism including a bobbin, a shuttle rotatable about an axis perpendicular to the plane of reciprocating movement of said needle bar guide, a shuttle race cover, and a thread guide plate means mounted on said shuttle race cover for positioning said needle thread loop; said thread guide plate means including a first opening for receiving said needle in one of said needle positions and deflector means disposed in a substantially horizontal plane located vertically above said shuttle, said deflector means at least partially closing said first opening to deflect a needle thread out of the path of said shuttle in said one needle position to preclude formation of a locked stitch.

2. A sewing machine as set forth in claim 1 wherein said thread guide plate means includes a second opening larger than said first opening, said first and second openings are interconnected whereby said needle is free to move laterally between said first opening and said second opening, and said interconnected first and second Openings cooperatively define an L-shaped opening.

3. A sewing machine as set forth in claim 1 wherein said thread guide plate means includes a second opening larger than said first opening, said second opening opens to one edge of said thread guide plate, and said first and second openings constitute separate openings interspaced by a web on said thread guide plate means.

4. A sewing machine as set forth in claim 1 wherein said deflector means is a separate deflector plate mounted on said shuttle race cover adjacent the lower side of said thread guide plate means and at least partially closing said first opening.

5. A sewing machine as set forth in claim 4 wherein said separate deflector plate includes a depending portion adjacent said first opening.

6. A sewing machine having a frame including a bed plate and a head structure above the bed plate, a needle bar guide mounted on said head for lateral swinging movement between left and right needle positions, a

needle carried by said needle bar guide for vertical reciprocating movement to'and from said bed plate, a loop forming mechanism on said sewing machine below said bed plate; said loop forming mechanism including a bobbin, a shuttle rotatable about an axis perpendicular to the plane of reciprocating movement of said needle bar guide, a shuttle race cover, and a thread guide plate means mounted on said shuttle race cover for positioning said needle thread loop; said thread guide plate means including a first opening for receiving said needle in one of said needle positions and deflector means disposed in a substantially horizontal plane located vertically above said shuttle, said deflector means being a separate deflector plate mounted on said shuttle race cover adjacent the lower side of said thread guide plate and at least partially closing said first opening to deflect a needle thread out of the path of said shuttle in said one needle position to preclude formation of a locked stitch, and said separate deflector plate being pivotably mounted on said shuttle race cover to allow said separate deflector plate to be adjustably positioned with respect to said first opening.

7. A sewing machine as set forth in claim 6 wherein said separate deflector plate includes a bent lip portion engageable by the hook of said shuttle if said separate deflector plate is in the path of said hook whereby upon engagement between said shuttle hook and said bent lip said separate deflector plate is pivotally movable out of the path of said shuttle.

8. A sewing machine as set forth in claim 6 wherein said thread guide plate means includes a second opening for receiving said needle'at said'other position and allowing said needle thread loop to be'engaged by said shuttle, and said first opening and said second opening constitutue separate openings interspaced by a web on said thread guide plate means.

9. A sewing machine as set forth in claim 6 wherein said thread guide plate means includes a second opening for receiving said needle at said other position and allowing said needle thread loop to be engaged by said shuttle, and said first opening and said second opening are interconnected whereby said needle is free to move laterally between said first opening and said second opening within said thread guide plate means.

References Cited UNITED STATES PATENTS 3,361,100 1/1968 Bono 112159 3,384,042 5/1968 Gianinazzi 112-158 FOREIGN PATENTS 1,093,318 11/1967 Great Britain.

RICHARD J. SCANLAN, 111., Primary Examiner US. Cl. X.R. 112228

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