US2482079A - Loop-spreader mechanism for chainstitch sewing machines - Google Patents

Description

F. F. ZEIER LOOP-SPREADER MECHANISM FOR CHAIN-STITCH SEWING MACHINES Sept 13,, $949.

' 4- Sheets-Sheet 1 Filed March 4, 1947 llll Pl [/VVE/Vfflfi. Frederick E Z6229)" ATTORNEY:

WITNESS.

J fifAza u 1949- F. F. ZEIER LOOP-SPREADER MECHANISM FOR CHAIN-STITCH SEWING MACHINES Filed. March 4, 1947 4Sheets-Sheet 2 I [NVENTflR fiedem'ok F Zez'er 14 7 T NESS'.

JM afiszczm I HTTORNEY Sept. 13, 149. F. F. ZEIER 2,482,079

' LOOP-SPREADER MECHANISM FOR CHAIN-STITCH SEWING MACHINES Filed March 4, 1947 4 Shegts-Sheet 3 I HIIIH j/ 43 11 [/VVENTOZZ.

ATTORNEY Sept. 13, 1949. F. F. ZEIER LOOP-SPREADER MECHANISM FOR C RAIN-STITCH SEWING MACHINES 4 Sheets-Sheet 4 Filed March 4, 1947 a3 a5 a? as f/VVENTUR Fi'ederzbk F Z9 zler WIT/V555:

ATTORNEX Patented Sept. 13, 1949 LOOP-SPREADER MECHANISM FOR CHAIN STITCH SEWING MACHINES Frederick F. Zeier, Stratfield,

The Singer Manufacturing Conn., assignor to Company, Elizabeth, N. J., a corporation of New Jersey Application March 4, 1947, Serial No. 732,184

6 Claims.

This invention relates to sewing machines and more particularly to those of the two-thread chain-stitch type employing a thread-carrying looper, and the invention has for an object to provide an improved loop-spreading mechanism for engaging and spreading one limb of the looperthread-loop to form with the needle-thread-loop which is about the looper the usual threadtriangle for entrance by the descending needle in forming the succeeding stitch.

Another object of the present invention is to provide a loop-spreader actuating mechanism having the component parts thereof so arranged that a minimum of effort is required to operate the mechanism, the parts can be readily assembled, manufacturing tolerances can be reasonably large, and necessary repair including the replacement of parts can be accomplished without excessive disassembly.

A further object of the present invention is to provide a loop-spreading mechanism in which the thread-engaging element may be universally adjusted in order to effect a very satisfactory timing of the thread-engagin element with the other stitch-forming devices.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attaincd thereby will be readily understood by those skilled in the art.

In the drawings,

Fig. 1 is a, front side elevational view, with a portion of the bed and cloth-plate in section, of a sewing machine embodying the present invention.

Fig. 2 is an enlarged top plan view of a portion of the machine-bed; the cloth-plate and the throat-plate having been removed to show more clrarly the mechanisms within the bed.

Fig. 3 is a transverse vertical sectional view taken substantially along the line 3-3, Fig. 2, showing the eccentric drive for the spreader mechanism and the anti-friction bearing interpoed between the periphery of the actuating eccentric and the pitman strap embracing said eccentric.

Fig. 4 represents a longitudinal vertical sectional view taken substantially along the line 4--4, Fig. 2.

Fig. 5 represents a longitudinal vertical sec- 2 tional view taken substantially along the line 5---5, Fig. 2.

Fig. 6 represents a transverse vertical sectional view taken substantially along the line 6-6, Fig. 2.

Fig. 7 is a. fragmentary top plan view of the looper and spreader, illustrating the looper just entering the needle-thread-loop during the loopseizing stroke of the looper.

Fig. 8 is a right side elevational view, partly in section, of the elements shown in Fig. 7.

Fig. 9 is a view similar to Fig. '7, but showing the looper at the end of its loop-seizing stroke and the spreader engaging one limb of the looperthread-loop preparatory to distending the same for entrance by the needle on its next work-penetrating stroke.

Fig. 10 is a, right side elevational view, partly in section, of the elements shown in Fig. 9.

Fig. 11 is a view similar to Fig. 9, but showing the looper retracting to shed the needle-threadloop and the looper-thread-loop fully distended by the spreader. v

Fig. 12 is a right side elevational view, partly in section, of the elements shown. in Fig. 11.

Fig. 13 is a fragmentary front ide elevational view of the sewin machine bed, showin a modification of the spreader-carrying arm adapted for use on a wide gauge machine. 7

Fig. 14 is a top plan view, with the cloth-plate and throat-plate-removed, of that portion of the sewing machine bed shown in Fig. 13.

Fig. 15 represents an enlarged vertical sectional view taken substantially along the line I 5-l 5, Fig. 14. r 7

Referring more in detail to the drawings, the invention is shown as embodied in a sewing machine comprising a frame includin a bed 20 from one end of which rises a standard 2| of an overhanging bracket-arm terminating in a head 22. J ournaled in the head 22 for endwise reciprocatory and laterallyvibratory movements is a needle-bar 23 carrying at its lower end a needleclamp 24 in which is fastened a pair of eyepointed threadecarrying needles 25. The needles 25 are adapted to penetrate work sustained on the work-support by a common form of presserfoot 26, which work-support includes a throatplate 21 and cloth- plates 28 and 29. The work is fed through the machine by means of the vibratory needles 25 and the cooperating feeddog 30 supported on a feed-bar 3| which derives its usual feeding motions from mechanism substantially similar to that forming the subject of my prior Patent No. 2,292,258, issued August 4, 1942.

Cooperating with the threaded needles in forming two-thread chain-stitches are the thread-carrying loopers 32 supported for oscillation in a vertical plane parallel to the line of feed in a looper-carrier: 33 mo unted'on a fixed fulcrurn-shaft- 3 isu pported at opposite ends in bushings 34 located in the transverse partitions 35 and 35 of the bed 23. The looper-carrier 33 is actuated through a rock-lever 31 and link 38 from a, crank 39 mounted on the end of a rotary main or bed-shaft 4E] journaled in suitable bearings H and 52 (Fig. 1) provided in the bed 23. It will be understood that the loopers 32 have only 'loopseizing and loop-shedding strokes and that these two motions are coordinated with the reciprocatory and vibratory feeding movements of the needles 25 to effect stitch;formation.

To assist in proper stitch-formation, each of the two-motion loopers 32 has cooperating there- I with a spreader-finger 43 (Fig. 2) which is adapted to engage and distend one limb of the looperthread-loop to form the usual thread-triangle with the previous needle-thread-loop for entrance by the descending needle. In one embodimerit of the invention asapplied to a narrow gauge machine (needles set relatively close to each other), the spread-ers 43 are preferably rigidly fastened to a flat carrier or arm 54 formed with a shank 45 Theshank 45 is slotted, as at 56, through which extends a clamp-screw 41 threaded into a carrier-arm holder or block 48 secured by set-screws 49 on the forward end of an endwise reciprocatory actuating or spreadersupporting bar 50. Adjustment of the spreader fingers 43 vertically and horizontally in a direction toward or away from the loopers 32 is accomplished by loosening theset-screws 49 and turning or shifting th'e block 48 on the spreadersupporting bar 50, while adjustment of the spreader-fingers in a substantially horizontal direction parallel with the lineof fee-d is accomplished by backing off the clamp-screw 41 and shifting the carrier ifrelative to the block 58. The block 48 is formed with a tongue 5| adapted to project into a groove52 provided in the shank of the carrier MQlimiting shifting of the carrier 55 relative to the'block 48 in a right line.

The spreader-supporting bar 59 is journaled for endwise movement in the spaced bearings 53 and i 54 (Fig. 2) of a bearing-bracket 55 detachably secured on a supporting lug 56 cast integral with the front wall 5'! and transverse partition 36 of r the bed 20, the screws58 and. locating pins 59 serving to fasten thebracket 55 in its alined position. The rearward end of the spreader-supporting bar 55 is preferably formed as a yoke 60 I in the limbs of which is freely journaled a horizontally disposed connector-pin 5| apertured,normal to its longitudinal axis, to slidingly receive the upwardly extending cylindrical lever-pin 52 of a driving rock-arm 63. The rock-arm 63 is fastened on a transverse spreader-driving rock-shaft 54 j ournaled at its opposite ends preferably in needlebearings fiiipressed into the side-walls of the bed 20, as clearly shown in Fig. 2. The spreader-driving shaft 54 is restrained against endwise shifting in its bearings 55 by two collars 56 clamped on the shaft 6 1. The'means for rocking the spreaderdriving shaft 64 comprises a horizontal rock-arm (Fig. 4) having a cylindrical body 61 provided with a shank 68 threaded into the spreader-driving shaft 54, a lock-nut 69 serving to prevent d accidental unthreading of said rock-arm, Slidingly embracing the cylindrical body 61 of the rock-arm is a sleeve-ball Ill seated in a socket H formed in the split upper end of an actuating pitman 12. The lower end of the pitman 12 embraces a needle-bearing l3 fitted on an actuating eccentric ll secured by set-screws 15 on the rotary bed-shaft 45. Disposed on opposite sides of the pitman T2 are two thrust-washers 15; the pitman l2, needle-bearing 13 and thrust-washers 15 being retained on the actuating eccentric M by a' flan'geill secured against the face of the eccentric M by screws 18 and locked on the rotary bed-shaft 40 by the set-screws 19. To minimize vibration during high speed operation of the mechanism, the eccentric I4 is formed with a weigh-ted section 8ll and the flange 11 is formed with a similar weighted section 8|, the two sections and 8| being disposed diametrically opposite the point of maximum eccentricity of the eccentric 15. To further assist in balancing the spreaderfrnechanism, the driving rock-arm 63 is formed with a. depending counterbalance 82 v (Figs. 1 and 3). The actuating'eccentric 14 is timed so that the spreader-finger 53 is reciprocated crosswise of the linev of seam'fo rmationat the proper time to spread the thread leading from the looper-eye to form the usual thread triangle with the previous needle-loop which is about the blade of the looper for proper entrance by the descending needle. The functioning of the spreader is illustrat d in Figs. 7 to. 12, inclusive. In Figs. '7

.. and 8, the needle 25, after reaching the lowermost pointof its stroke, has begun its ascending stroke and has castout a thread-loop NT which is just being entered by the beak of the looper 32. During this part of the stitch-forming cycle, ;the spreader 53 does not perform any useful function; Figs. 9 and 10 disclose the looper, at the end of its loop-seizing stroke and the needle 25 at the highest point of its stroke. It will be seen that the spreader 43'has engaged a limb of the "looper-thread LT and ispreparing to carrying said limb to a position further to the right. Figs. 11 and 12 disclose the looper 32 retracting to shed the needle-thread-loop NT, the needle 25 descend- O ing to enter'the thread triangle and the spreader 53 at the end ofits-loop-distending stroke. From the above, it will be understood that the spreaderfinger- 43 engages and spreads one limb of the looper thread so that the needle 25 on its descending stroke will unerringly enter the spread thread-triangle, regardless of the fact that the needIe apertu're is not stationary but is formed in the feed-dog 30'and shifts back and forth in the'line'of feed.

Figs. 1, 2, 5 and 6 are illustrative of a spreader mechanism as applied to a narrow gauge sewing machine, i. e. one in which the needles and loopers are relatively closely spaced. Figs. 13 and 14 disclose a modification'of the spreader mechacnism which-is adapted for wide gauge sewing machines. Referring to these two figures it will be observed th'attheloopers 32 are widely spaced and are supported-by 'a'looper-carrier 83 journaled for oscillation on'a fixed fulcrum-shaft 34 supported at opposite endsin the bushings 34' located inthe transverse partitions 35 and 36 of the bed 25. The looper-carrier 83 is oscillated on the fulcrum-shaft 34 by the'same means hereinbefore described in connectionwith the loopercarrier33. Cooperating with the widely spaced loopers 32 are the spreader-fingers 84 (Fig. 14) preferably integral with a carrying-bar 85. The carrying-bar 85 preferably has a rectangular cross-section andis supported adjacent its opposite ends for'endwise reciprocation against the under side of the throat-plate 2'! by two slotted bearing-blocks or guides 86, each of the bearingblocks being provided with elongated holes 81 through which extend screws 88 threaded into the throat-plate 21. The elongated holes 8'! provide for limited adjustment of the spreader-fingers 84 in a plane parallel to the under surface of the throat-plate 21. The spreader carrying-bar 85 is reciprocated endwise by the actuating bar 55 and the means employed for connecting said carrying-bar 85 to said actuating bar 50 preferably comprises a connector-head 89 secured on the outer end of the actuating bar 50 by the setscrews 90 affording limited adjustment of said head lengthwise of said actuating bar 59. The other end of the connector-head 89 is formed with a channel 9! opening into the upper face of the connector-head, into which open topped channel projects a block 92 depending from the right hand end portion of the carrying-bar 85. The blockand-channel connection with the actuating bar 50 facilitates removal of the throat-plate 21 and spreader-fingers 84 as a unit from the machine cloth-plate 28. The block-and-channel connection also accommodates whatever misalinement which may exist between the carrying-bar 85 and the actuating-bar 50.

From the foregoing, it will be understood that I have devised a spreader operating mechanism having the component parts thereof interconnected in a manner to eliminate binding in the event the parts are slightly misalined. In fact, by virtue of the universal connections between the various elements of the operating mechanism, manufacturing tolerances as far as alinement is concerned may be large and therefore easily obtainable. The presence of the detachable bearing-bracket 55 is advantageous owing to the fact that machining of the bed 20 is simplified and the final assembly of the spreader operating mechanism is facilitated. The universal adjustment of the spreader-fingers relative to the loopers permits the accurate timing of the spreader-fingers with respect to the movements of the loopers, resulting in a perfect cooperation between said spreader-fingers and loopers.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a frame including a bed, the combination with a thread-carrying reciprocatory needle, of complemental stitchforming mechanism including a thread-carrying looper, means for imparting loop-seizing and loopshedding movements to said looper, a loopspreader, means for operating said loop-spreader including an actuating bar provided with a connector-pin, a bracket detachably secured to said bed and providing a bearing for said actuating bar, a rock-shaft, means for operating said rockshaft, and means connecting said rock-shaft to said actuating bar including a rock-arm fast on said rock-shaft and having a lever-portion thereof slidingly disposed in said connector-pin.

2. In a sewing machine having a frame including a bed, the combination with a thread-carrying reciprocatory needle, of complemental stitchforming mechanism including a thread-carrying looper, means for imparting loop-seizing and loop-shedding movements to said looper, a loopspreader movable transversely of the movements j 6 of said looper, an endwise movable loop-spreader actuating bar provided with a connector-pin, a carrier for said loop-spreader adjustably secured on said actuating bar, a bracket providing a bearing for said actuating bar detachably secured to said bed, a rock-shaft, means for operating said rock-shaft, and means connecting said rock-shaft to said actuating bar including a rock-arm secured on said rock-shaft and having a lever-portion thereof slidingly disposed in said connector-pin.

3. In a sewing machine having a frame including a bed, the combination with a threadcarrying reciprocatory needle, of complemental stitch-forming mechanism including a threadcarrying-looper, means for imparting loop-seizing and loop-shedding movements to said looper, a loop-spreader, an actuatin bar supporting said loop-spreader and endwise movable in a direction substantially normal to the loop-seizing and loop-shedding movements of said looper, a rockshaft journaled in said bed transversely of said actuating bar, a rotary shaft journaled in said bed, means including a universal connection for operatively connecting said rock-shaft to said rotary shaft, and means including a second universal connection for connecting said actuating bar to said rock-shaft.

4. In a sewing machine having a frame including a bed, the combination with a thread-carrying endwise movable needle, of complemental stitch-forming mechanism including a threadcarrying looper, means for imparting loop-seizing and loop-sheddin movements to said looper, a loop-spreader, an actuating bar endwise movable in a direction substantially normal to theloop-seizing and loop-shedding movements of said looper, a holder mounted on said actuating bar, a carrier for said 10op-spreader adjustably secured to said holder, a rock-shaft journaled in 3 said bed and disposed transversely of said actuating bar, means for operating said rock-shaft, and means operatively connecting said actuating bar to said rock-shaft, said means having capacity to accommodate slight misalinem'ent between said actuating bar and said rock-shaft.

5. In a sewing machine having a frame including a bed, the combination with a thread-carrying endwise movable needle, of complemental stitch-forming mechanism includin a threadcarryin looper, means for moving said looper so that the beak thereof travels in a vertical plane, a loop-spreader, a bracket detachably secured to said bed, an actuating bar journaled in said bracket for reciprocation in a direction substantially normal to the plane of movement of said looper-beak, means adjustably securing said spreader to one end of said actuating bar, a rockshaft journaled in said bed and disposed substantially parallel with the plane of movement of said looper-beak, means including a universal connection operatively connecting said rock-shaft with said actuating bar, a rotary main-shaft journaled in said bed and disposed substantially parallel to said actuating bar, and means connecting said rock-shaft to said rotary main-shaft.

6. In a sewing machine having a frame including a bed and a removable throatplate, the combination with an endwise reciprocatory threadcarrying needle, of complementary stitch-forming mechanism including a thread-carrying looper, means for imparting loop-seizing and loop-shedding movements to said looper, a loopspreader, a carrying-bar supported for endwise sliding movement on the under side of said 2,48230791 7 8*. throat-plate, a blockdepending from said carry- Y REFERENCES CITED ing-b'ar, an actuating bar 'journaled for endwise reciprocation in said bed, means for reciprocating said actuating bar, and a connector-head The following refefences are of record in the file of this patent:

fixed on said actuating bar having an open topped 5 UNITED STATES PATENTS channel into which projects the block depending Number Namev Date fmm Sam carrymg'bar- 1,443,084 Mofiatt et a1. Jan. 23, 1923 1,995,078 Rubel Mar. 19, 1935 FREDERICK ZEIER- 2,312,858 Zeier Mar. 2, 1943

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