Manual Needle Elevating Device

Abstract

A mechanism in a zigzag sewing machine having a basting stitch device which operates by unlatching a needle bar from an endwise reciprocatory drive means during an extreme excursion of a needle bar gate carrying the needle bar. A latch release member, positioned adjacent the needle bar gate, may be manually elevated to a position where it will strike a lever mounted on the latch mechanism which will trip the latch mechanism at any position of the needle bar gate. A presser bar lifting lever, when elevated to a position beyond normal lift position, will lift a presser bar guide block to a position where it will strike a lug extension on the latch release member, thereby causing elevation of the latch release member to disconnect the needle bar from its endwise reciprocatory driving mechanism. A tension spring will elevate the needle bar to its upper most position when the needle bar is thus disconnected from its driving mechanism.

Description

BACKGROUND OF THE INVENTION

The invention is a mechanism which operates on a basting stitch device as originally set out in the U.S. Pat. No. 3,559,601, Feb. 2, 1971, to E. J. Tullman wherein a zigzag sewing machine having a latch mechanism attached to a needle bar and connecting the needle bar to a reciprocating drive mechanism may be caused to unlatch the needle bar from its driving mechanism during an extreme excursion of the zigzag mechanism beyond the normal zigzag sewing range of the sewing machine. The above noted patent discloses a bracket attached to a sewing machine frame which is struck by the latch mechanism mounted on the needle bar, when the needle bar is made to undergo an extreme excursion under the influence of a special basting cam. A latch lever part of the latch mechanism attached to the needle bar is caused to rotate about its pivot by the impact, thereby disconnecting the needle bar from its driving mechanism. A second bracket is utilized to trap the latch lever, and the attached needle bar, in an elevated position, until the needle bar is returned from its extreme excursion by the basting cam, whereupon a stitch is made.

In the U.S. Pat. No. 3,782,311 of Jan. 1, 1974 an improvement to the above noted U.S. Pat. No. 3,559,601 is disclosed wherein the bracket to unlatch the needle bar from its reciprocatory driving mechanism is carried by a needle bar gate arranged to have substantial motion relative to the needle bar during zigzag motion. When the needle bar is unlatched from its driving mechanism on an extreme excursion of the needle bar, it is brought to and held in an elevated position by an extension spring attached thereto.

In the above patent and application are disclosed sewing machines wherein the operation of the needle bar may be interrupted under the influence of a program means such as a cam; and the needle bar can be kept in an elevated inoperative state while the sewing machine continues to feed the work material.

There are devices in the sewing machine art wherein the needle bar and needle may be elevated out of the work material when the presser foot is lifted from the work material. Such a device is disclosed in the U.S. Pat. No. 709,354, Sept. 16, 1902, to O'Donnell. It is also known to cause a sewing machine to stop in a position where the needle bar may be in the elevated position or in the lowered position at the discretion of the sewer. Both of these systems are characterized by their complexity and relatively high cost, particularly the latter system, which is usually confined to industrial machines where its cost is offset by the savings in time realized as a consequence of automatic positioning of the sewing machine needle obviating the requirement for turning the handwheel to achieve the selected position.

SUMMARY OF THE INVENTION

This invention eliminates the above noted drawbacks in that a simplified mechanism has been devised which, although not automatic, allows a sewing machine operator, at a touch, to elevate the needle bar at anytime, even during sewing. Through this same invention a sewing machine operator may selectably elevate the sewing machine needle out of the work material when raising the presser foot. These improvements may be added to a sewing machine having a basting stitch mechanism attached to a needle bar, as explained above, by the addition of a bare minimum of parts and consequently at minimum additional cost or complexity.

As noted above the latch mechanism affixed to the needle bar includes a latch lever having an ear or an extension which is struck by a bracket when the needle bar is positioned to an extreme excursion beyond the normal zigzag range of the sewing machine. The extreme excursion of the needle bar may be occasioned by a special basting stitch cam operating on a needle bar gate carrying the needle bar. The latch lever pivots about a eccentric collar on the latch mechanism when impeded by the bracket from further lateral motion with the needle bar, and disengages a latch surface on the latch lever from engagement with the endwise reciprocatory drive mechanism of the sewing machine. When the needle bar is thus disengaged from the driving mechanism it is elevated to its uppermost position by an extension spring connected to the needle bar.

In the invention, a second lever is mounted on the latch mechanism in a position such that when it is rotated to coact with the latch lever, it will also effect disengagement of the needle bar from the driving mechanism of the sewing machine. A latch release member is slidably supported adjacent an arm of the second lever. The latch release member, when elevated, is positioned to cooperate with the arm of the second lever to cause the second lever to rotate and co-act with the latch lever to separate the needle bar from the driving mechanism of the sewing machine. A lug extension on the latch release member is located above a presser bar guide block so that when the presser bar is elevated to a high lift position, the presser bar guide block strikes the lug extension and also positions the latch release member to cooperate with the second lever, rotating it and thereby the latch lever to disconnect the needle bar from its driving mechanism. In both situations the needle bar, when disengaged from its driving mechanism is elevated to its uppermost position by the tension spring. The arm of the second lever, or alternatively the latch release member, may be made of dimensions sufficient to insure cooperation with each other no matter the position of the needle bar during zigzag sewing.

DESCRIPTION OF THE DRAWINGS

With the above and additional objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 is a head end elevational view of a sewing machine viewed from the exterior of the sewing machine and showing the relation of the various parts in the head to the invention;

FIG. 2 is a front elevational view of the sewing head portion of the sewing machine shown in FIG. 1;

FIG. 3 is a detached and enlarged front elevation of the latch mechanism attached to the needle bar;

FIG. 4 is a perspective view of the upper half of the needle bar and gate showing the latch mechanism attached to the needle bar in the disengaged position with respect to the driving mechanism causing needle bar reciprocation;

FIG. 5 is an elevational view of the sewing head portion detached from the sewing machine and viewed from the interior of the sewing machine, i.e., viewed from a direction opposite to that of FIG. 1 and showing the operation of detaching the needle bar from the driving mechanism by manual means;

FIG. 6 is an elevational view of the sewing head portion similar to FIG. 5 but showing the operation of detaching the needle bar from the driving mechanism by super-elevation of the pressure bar lifter; and

FIG. 7 is a cross-sectional view taken substantially along line 7--7 of FIG. 5 showing the relationship between the latch release member, presser bar guide block and latch mechanism affixed to the needle bar.

In FIG. 1 is shown a head portion 10 of a sewing machine having a support bracket 11 affixed thereto by screws 12. The support bracket has an upper forwardly extending arm 13 and a lower forwardly extending arm 14. Journaled in the support bracket 11 within the upper forwardly extending arm 13 and the lower forwardly extending arm 14 is a gate 15; having an upper rearwardly extending arm 16, and a lower rearwardly extending arm 17. Inserted in the upper rearwardly extending arm of the gate 15 is an upper bearing having an outer spherical surface 20 and a coaxial internal bearing surface (not shown). Inserted into the lower rearwardly extending arm 17 of the gate 15 is a lower bearing 21 (See FIG. 2) having both an internal bearing surface, and, spaced therefrom, a socket. A spherical headed rivet 22 affixed to the lower forwardly extending arm 14 of the support bracket 11 has its spherical head protruding into the socket of the lower bearing. A needle bar 23 is supported for endwise reciprocation in the internal bearing surface of the upper bearing in the upper rearwardly extending arm 16 of the gate 15 and in the internal bearing surface of the lower bearing 21 (see FIG. 2) in the lower rearwardly extending arm 17 of the gate 15. A socket bearing 24, having an internal clearance hole for the needle bar 23, is slidably mounted in a bore in the upper forwardly extending arm 13 of the support bracket 11 and provides the socket for the outer sperical surface 20 of the upper bearing mounted in the upper rearwardly extending arm 16 of the gate 15. The position of the socket bearing 24 may be fixed by clamping screw 25 (FIG. 2) accessible from the front of the upper forwardly extending arm 13 of the support bracket 11. The needle bar 23 extends through an elongated opening 26 in the lower forwardly extending arm 14 of the support bracket 11 which provides sufficient clearance for the needle bar to undergo lateral zigzag motion.

Attached to the lower end of the needle bar 23 is a needle 27, which cooperates with a looptaker (not shown) in the bed 28 of the sewing machine below the throat plate 29. A presser foot 30, affixed to a presser bar 31, is utilized to urge work material into contact with a feeding mechanism (not shown). The presser bar is journaled in a bearing 32 which is affixed in a bore in the support bracket 11 by screw 33. The upper end of the presser bar 31 has affixed thereto by screw 36 a presser bar guide block 34. The presser bar guide block 34 has a tang portion 35 slidable in a slot between the support bracket 11 and the sewing machine frame to prevent undesireable rotation of the presser foot 30. The tang portion 35 of the presser bar guide block 34 also co-acts with a presser bar lifting lever 37, journaled on the support bracket 11, to raise the presser foot from contact with the work material in the usual manner.

Carried by the needle bar 23 is a latch mechanism 42 (See FIGS. 1, 3 and 4). The latch mechanism 42 includes a rectangular collar 43 which is affixed to the needle bar 23 by a screw 44 having an elongate head 45. Located on the front side of the rectangular collar 43 and supported on an eccentric collar 46, held positioned to the rectangular collar by a screw 47, is a latch lever 48. The latch lever 48 has a forwardly extending ear 49 spaced from the eccentric collar 46 and rearwardly extending ear 50 having a latch surface 51 also spaced from the eccentric collar.

Slideable on the needle bar 23 below the latch mechanism 42 is a pivot post 53. The pivot post 53 is held captive on the needle bar 23 by a bifurcated portion 54 of a driving stud 55. The driving stud 55 is driven in the usual manner to reciprocate on the needle bar 23 by a connecting link 57 and a crank 58 mounted on a horizontal arm shaft 59 (see FIG. 2).

The rearwardly extending ear 50 and latch surface 51 are located a sufficient distance from the eccentric collar 46 to retain the bifurcated portion 54 of the driving stud 55 in intimate contact with rectangular collar 43 when the latch surface 51 is engaged with a lower surface 62 on the bifurcated portion 54 of the driving stud 55. To achieve the intimate contact desired the eccentric collar 46 may be rotated and its adjusted position locked by the screw 47. To facilitate engagement of the latch surface 51 with the lower surface 62 of the bifurcated portion 54 of the driving stud 55, the lower surface is slightly tapered (see FIGS. 3 and 4). A torsion spring 61 mounted on the eccentric collar 46 behind the latch lever 48 forces the latch lever to rotate in a counter-clockwise direction as viewed in FIG. 3 to continually urge the latch surface 51 into engagement with the lower surface 62 of the bifurcated portion 54 of the driving stud 55. An extension 52 of the rectangular collar 43 fits between the bifurcations 54 to stabilize the needle bar 23 when the latch mechanism 42 is engaged.

Thus when the driving stud 55 is engaged with the needle bar 23 by means of the latch mechanism 42 affixed to the needle bar, the needle bar 23 is caused to undergo endwise reciprocation. When the latch surface 51 is disengaged from the lower surface 62 of the bifurcated portion 54 of the driving stud 55, the needle bar 23 and latch mechanism 42 affixed thereto is held in an elevated position as will be explained below and the pivot post 53 will slide freely on the needle bar 23 without causing endwise reciprocation of the needle bar.

The needle bar gate 15 has attached to its forward surface by screws 66 a bracket 67 the body of which extends behind the needle bar gate to co-act with the forwardly extending ear 49 of the latch lever 48. The cooperation of this bracket 67 with the forwardly extending ear 49 of the latch lever 48 is more fully disclosed in the U.S. Pat. No. 3,782,311 of Jan. 1, 1974. For the purposes of this patent application it is sufficient to note that when a cam mechanism (not shown) causes a linkage 69 to move to an extreme rightward position as viewed in FIG. 2 a driving post 70, to which the linkage is attached and which is itself affixed to the rear most portion of the upper rearwardly extending arm 16 of the gate 15, will cause the bracket 67 when properly adjusted to cooperate with the forwardly extending ear 49 of the latch lever to disengage the latch lever from the lower surface 62 of the bifurcated portion 54 of the driving stud 55.

As can be seen in FIG. 3 a post 75 protrudes from the rectangular collar 43 opposite screw 44 having the elongate head 45. Visible in FIGS. 3, 4, 5 and 6, the post 75 carries a second lever 76 which is held thereon by snap ring 77. The second lever 76 has an ear 78 arranged to cooperate with an ear 79 of the latch lever 48. The post 75 serves as a pivot for the second lever 76. The second lever 76, on that side of the post 75 opposite that of the ear 78 of the second lever, is formed with an extension 80 at a right angle to the second lever 76. The extension 80 is formed with an abutting surface 81 whose purpose will be described below.

In FIGS. 5 and 6 can be seen a latch release member 84 arranged to slide adjacent the support bracket 11. The latch release member 84 is held adjacent to the support bracket by pin 85 affixed to support bracket and protruding through a lower cam slot 86 in the lower portion of the latch release member. The upper portion of the latch release member 84 is supported by a shoulder screw 87 protruding through an upper cam slot 88 in the upper portion of the latch release member. The shoulder screw 87 is threaded into a member 89 which is adjustably affixed to a mounting plate 90 indicated in FIG. 1.

A forward edge 91 of the latch release member 84 cooperates with the abutting surface 81 of the extension 80 of the second lever 76 when the latch release member is urged upwardly due to the configuration of the cam slots 86 and 88 causing the latch release member to advance forwardly as it is elevated. The abutting surface 81 of the extension 80 of the second lever 76 is made of sufficient dimension to insure co-acting with the forward edge 91 of the latch release member 84 regardless of the position of the needle bar 23 and the latch mechanism 42 attached thereto.

Attached to an uppermost corner 93 of the latch release member 84 is one end of a tension spring 95. The opposite end of the tension spring 95 is attached to the extremity of the post 75 protruding from the rectangular collar 43. The tension spring 95 serves to maintain the latch release member 84 in its downward position unless urged upwardly. The tension spring 95 also lifts the needle bar 23 and the latch mechanism 43 attached thereto to an elevated position whenever the latch surface 51 is disengaged from the bifurcated portion 54 of the driving stud 55. On the side of the support bracket 11 opposite that on which the tension spring 95 is located, a resilient abutment means 97 is secured by a screw 99 to a cut-out section 98 of the support bracket 11. An abutment end 100 of the abutment means 97 is held by bracket 101, adjustably secured by screw 103 in a second cut-out section 102 of the support bracket. The end 100 of the abutment means 97 impinges on the elongate head 45 of the screw 44 affixing the rectangular collar 43 to the needle bar 23. The abutment means 97 limits the height to which the needle bar 23 and the attached latch mechanism 42 may be carried in order to facilitate relatching of the needle bar to the endwise reciprocatory driving mechanism. The position of the bracket 101 is adjustable with respect to the support bracket 11 to provide the necessary adjustability for this purpose.

Thus when the latch release member 84 is elevated it is caused to move forwardly due to the configuration of the cam slots 86 and 88. With the position of the member 89 properly adjusted by connection with the mounting plate 90 the forward edge 91 of the latch release member 84 will cooperate with the abutting surface 81 of the extension 80 of the second lever 76 to cause this lever to rotate counter-clockwise, as seen in FIGS. 5, and 6, which will cause the ear 78 of the second lever to cooperate with the ear 79 of the latch lever 48 thereby rotating the latch lever and disconnecting the latch surface 51 from the lower surface 62 of the bifurcated portion 54 of the driving shaft 55. The needle bar will be elevated by the tension spring 95 as restrained by the abutment means 97.

Elevation of the latch release member 84 by means of a projection 105 on the lower end of the latch release member at any time during sewing will cause the machine to skip stitches in order to pass over an impenetrable object, or to sew a series of basting stitches at the pleasure of the operator without placing the machine into the basting stitch mode and during normal sewing. This mechanism may also be used when the sewing machine has been stopped with the needle in the work material to elevate the needle bar out of the work material. Referring to FIG. 5 the position of the components prior to elevation of the latch release member 84 are shown in dotted lines. When the latch release member is elevated as is shown in the solid lines the latch mechanism is disengaged from the driving mechanism for the needle bar, carrying the latch mechanism and the needle bar to an elevated position.

Referring to FIGS. 6 and 7 the latch release member 84 has protruding from the rear surface thereof a lug extension 107. The lug extension 107 is positioned above the presser bar guide block 34, and cooperates with the presser bar guide block when it is raised to a lift position beyond the normal presser foot raising position to elevate the latch release member 84 and cause the latch mechanism to be disengaged from the driving mechanism for the needle bar. Thus if the sewing machine is stopped with the sewing needle 27 in the work material and the operator wishes to remove the work material from the machine, by raising the presser bar lifting lever 37 slightly more than the normal lifting position the needle may be withdrawn from the work material to facilitate removal thereof.

Thus by the addition of a second lever 76, the latch release member 84, tension spring 95, and abutment means 97 to a sewing machine having a latch mechanism 48 affixed to the needle bar; capability for manual basting or removal of the needle from the work material has been added to the machine at minimum expense. The operation of this mechanism is independent of the position of the needle bar and may be activated when the needle bar is located in the goods or partially elevated or whether the needle bar is in any position of zigzag motion.

It is apparent that provision may be made for super-elevating the needle bar 23 when raising the presser bar lifting lever and thereby the presser foot 30 to a super-elevated position. This may be accomplished by raising the resilient abutment member 97 by an extension to the presser bar guide block 34 which contacts the abutment member when the guide block and presser foot is raised to a super-elevated position. The needle bar 23 will thereby be elevated an additional amount by the tension spring 95 before being restrained by the abutment member 97. Lowering the presser foot will release the abutment member and allow it to act on the screw 44 to permit re-engagement of the driving mechanism to the needle bar 23.

Claims

We claim:

1. In a sewing machine having a frame, a needle bar carried for endwise reciprocation in said frame, a driving mechanism for effecting endwise reciprocation of said needle bar, a latch mechanism arranged between said needle bar and said driving mechanism for selectively disconnecting said driving mechanism from said needle bar, the improvement comprising a latch release member shiftably supported on said sewing machine frame for movement alternatively into and out of a position for releasing said latch mechanism, a tension spring arranged to act upwardly on said needle bar, means responsive to movement of said latch release member into position for releasing said latch mechanism for increasing the tension in said spring, and abutment means carried on said sewing machine frame for limiting the uppermost position of said needle bar.

2. In a sewing machine as set forth in claim 1 in which said spring is attached to said needle bar and to said latch release member so that movement of said latch release member into a position for releasing said latch mechanism increases the tension in said spring thus biasing said needle bar upwardly with increased force and also biasing said latch release member in a direction out of position for releasing said latch mechanism.

3. In a sewing machine as set forth in claim 2 in which said latch release member is arranged in said sewing machine frame closely adjacent to the path of reciprocation of said needle bar, and in which said latch release member includes a projection protruding exteriorly of said sewing machine frame and formed with a finger grip for operator influence in selectively disconnecting said driving mechanism from said needle bar.

4. In a zigzag sewing machine having a frame, a needle bar carried for endwise reciprocation and sideways oscillation in said frame, a driving mechanism for effecting endwise reciprocation of said needle bar, a latch mechanism arranged between said needle bar and said driving mechanism for selectively disconnecting said driving mechanism from said needle bar, means including a pattern information cam for selectively disconnecting said mechanism from said needle bar for the formation of basting stitches, a presser foot and a presser foot lifting mechanism; wherein the improvement comprises a latch release member shiftably supported on said sewing machine frame for movement alternatively into and out of a position for releasing said latch mechanism, said latch release member including a projection protruding exteriorly of said sewing machine frame and formed with a finger grip for operator influence in selectively disconnecting said driving mechanism from said needle bar, said latch release member also including a lug extension arranged for cooperation with said presser foot lifting mechanism for movement of said latch release member into a position for releasing said latch mechanism upon elevation of said presser foot by said presser foot lifting mechanism into a predetermined elevated position of said presser foot.