US2016938A - Sewing machine - Google Patents

Description

Oct. 8, 1935. G. A. FLECKENSTEIN SEWING MACHINE 7 Filed Sept. 6, 1934 Geowe Flccknaiein rained a. c, 1935 2,016,938

UNITED STATES PATENT OFFICE SEWING MACHINE George A. Fleckenstein, Stratford, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application September 6, 1934, Serial No. 742,918

12 Claims. (Cl. '112-235) This invention relates to improvements in seweluding a feed-dog 9, carried by a feed-bar l ing machines and. has for its primary object to and projected through suitable feed-slots in the provide for efficiently advancing work past the throat-plate 2. Any suitable mechanism may be stitch-forming mechanism of a sewing machine employed for impartin h ual rising and fallhaving a four-motion feed yieldingly opposed by ing, and the work-advancing and return move "'5 a presser-device. ments to the feed-dog.

More specifically, the invention has for its obe d y pp to the feed-(g 9 is a P ject to minimize friction in the bearing or bear- 0 ll de a ab y Secured t t e lower end of ings of a presser-foot carrying bar shifted enda vertically disposed presser-bar l2 journaled for V 10 wise d t u t th tio of a workdendwise movement in-a fixed bearing bushing i31 Vancing feed mechanism operated at high speed. The bu h n it i suitably secured i an p r ure With the above and other objects in view, the in the lower wall of the bracket-arm head 3 invention comprises the devices, combinations to extend within said head and to dep thereand arrangements of parts hereinafter described from a substantial distance. Preferably, the

in connection with the acompanying drawing bushing l3 d p m e ead 3 he maxiwhich illustrates several embodiments of the inm extent pe the requisite Vertical Vention, from which the several features of the m v nt f th Presser-foot H, to thereby ininvention and the advantages attained thereby crease the effectiveness of ,said bearing in pwill be readily understood by those skilled in s i th P s r against the side thrust th t 1 thereof occasioned by the engagement of the 20 In the accompanying drawing, Fig. 1 is a front P o by the feed-(10g during W k-adend elevation, partly in section, of a sewing ma- Vaneihg movements of the letter at high p d chine containing one embodiment of the present p a o invention. Fig. 2 is an enlarged sectional View t its pp end t D Slidingly of the carrying bracket oi the thrust-absorbters a capped bearing-bu l4 di stabh 25 ing roller, the section being taken substantially threaded in h pp r W l f h br k -arm on the line 2-2 of Fi 1. Fi 3 is an enlarged h ad 3 and h ld s ur d in ad ust d p siti n y bottom plan view of the roller-carrying bracket a t-S rew 3- e Dr -bar 2 has a bore shown in Fig. l as secured upon the pressert pr f a y extending th maj r p ti n f th bar bearing bushing, the presser-bar being shown ngth of the bar and from the upp end therein ection, Fig 4 is a, fragmentary front, end Of, to receive a C011 spring 51 and anabutment elevation of the bracket-arm head of a sewing Ted The Tod s n p d between the machine containing a modified friction-reducing l 0f the bushing 14 and the 0011 Spring device for the presser-bar. Fig. 5 is a rear side whereby the P s ai s y i s y u d downelevation of the modification shown in Fig. 4. W rdIy toward the work-support under an ad- 35 Figs. 6 and 7 represent front end and rear side Li a e. p s

views in elevation of another modification of Embracing the Dresser-103118 e usual lifterth present im rove e t, sleeve iii, of which the upper end engages a col- Referring to the drawing, a sewing machi lar 2E clamped upon the presser-bar and the lower containing the present improvement is illusd ar i s a a ally x nd n a m en ag trated as having a cloth-plate I, provided with able by the usual h nd lifter-lever 22 pivotally the usual throat-plate 2, and a bracket-arm overmounted up e br c et-arm head.

hanging the cloth-plate, which brack tt r In the form of the improvement illustrated in minates at its free end in a hollow head 3. Figs- 1 t0 3 inclusive of the d w there s Journaled for vertical reciprocation in the mp y a screw 3 p the p ion of th bracket-arm head 3 is a needle-bar 4, carrying fixed bushing it below the head 3, a split collar at its lower end a needle 5 and connected by a 25 having depending p d bracket-members 25 link 6 to a crank-disk 1 carried by a rotary disposed at the rear side of the presser-bar I2.

needle-reciprocating shaft 8. The needle 5 co- Mounted between the bracket-members 25, for

operates, in the formation of stitches, with suitrotation about an axis transverse to the line of 50 able loop-taker mechanism (not shown) disposed feed, is a roller 26 journaled upon an eccentric below the cloth-plate. portion 2i of a shouldered spindle or bolt 28 ro- The work to be stitched is intermittently adtatably adjustable in suitable apertures provided vanced across the cloth-plate l byafeeding mechin the bracket-members 25 and clamped in set anism of the lower four-motion type and inposition by a nut 29. The roller supporting spindle 28 is preferably set so that, normally, the roller 26 is barely in contact with the rear face of the presser-bar l2, it being obvious of course that the roller may be adjusted relatively to the presser-bar by turning the spindle 28.

At slow speeds of operation of the sewing machine, the presser-bar spring I! effectively acts to lower the presser-foot ll upon the throatplate 2, with the work-disengaging movement of the feed-dog 9 and before the feed-dog again en gages the work in a succeeding work-advancing movement thereof. However, at higher speeds of operation of the machine, the friction between the presser-bar and its bearing or bearings is so materially increased by the thrust of the feeddog in its action to advance the work, that the spring I! cannot function to completely lower the presser-foot between consecutive work-disengaging and work-engaging movements-of the feed-dog. -In this connection, it is to be borne in mind that there are limits to the pressure which may be exerted, without detriment, by presserbar springs and particularly with certain classes of work. However, the roller 26 constitutes antifriction means absorbing excessive lateral thrusts imparted to the presser-bar, thereby relieving the presser-bar bearing from excessive friction.

In the modification of the improvement illustrated in Figs. 4 and 5 of the drawing, there is provided a bow-spring 30, of which the upper end engages the rear outer face of the bracket-arm head 3 above the lifter-arm 2| and the suitably rounded lower end engages the rear face of the presser-bar below the bearing busrnng [3. The bow-spring 30 is adjustably tensioned by a screw 3| threaded into the head 3, whereby said spring yieldingly engages the presser-bar l2 with sulficient pressure and in a suitable direction to counteract excessive bearing-friction inducing thrusts of the feed-dog upon the presser-bar. The spring 30 is provided with a slot 32 affording clearance for movement of the hand lifter-lever 22 and the lifter-arm 2!.

In another modification illustrated in Figs. 6 and 7 of the drawing a split collar 33 is clamped upon the portion of the bushing 13 below the head 3, said collar having a rearwardly extending and flat-sided ear 34. The ear 34 carries a fulcrum-pin 35 projecting from the opposite flatsides of said ear in a direction transverse to the direction of feed. Pivotally hung upon the opposite ends of said fulcrum pin to depend therefrom in parallel relation are a pair of spaced arms 36 carrying a spindle or bolt 3'! upon which is journaled a roller 38 disposed between said arms 36. The spindle 31 preferably corresponds with the spindle 28 illustrated more particularly in Fig. 2 of the drawing, in that it likewise has an eccentric portion for adjustably supporting the roller 38 and is secured in set positions by a nut 39; Engaging the rearward faces of the arms 35, are the spaced members 40 of a forked bowspring 4 I, of which the opposite end bears against the rearward face of the head 3. A screw 42 threaded into said head 3 serves to suitably tension the spring 4! to counteract the excessive friction-inducing tendency between the presserbar and its bearings at high speeds of operation of the machine. It will be understood that the modification illustrated in Figs. 6 and 7 of the drawing constitutes a combination of the antifriction thrust-absorbing means of Figs. 1 to 3 of the drawing and the yielding thrust-absorb ing means of Figs. 4 and 5 of the drawin posed to' work-engaging movements of said feeddog, a presser-foot carrying bar, a presser-bar bearing providing for endwise sliding movements of the presser-bar thereupon, and thrust-absorbing means opposing lateral thrust of the presserbar upon the rear wall of said bearing in the direction of feed.

3. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a four-motion feed-dog, a presser-foot yieldingly opposed to work-engaging movements of said feed-dog, a presser-foot carrying bar, a presser-bar bearing, and anti-friction means opposing lateral thrust of the presser-bar upon said bearing.

4. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a fourmotion feed-dog, a presser-foot yieldingly opposed to work-engaging movements of said feed-dog,

a presser-foot carrying bar, a presser-bar bearing,

and yielding thrust-absorbing means opposing lateral thrust of the presser-bar upon said bearing.

5. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a fourmotion feed-dog, a presser-foot yieldingly opposed to work-engaging movements of said feeddog, a presser-foot carrying bar, a presser-bar bearing providing for endwise sliding movements of the presser-bar thereupon, and thrust-absorbing means carried by said bearing opposing lateral thrust of the presser-bar upon said bearing.

6. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a four-motion feed-dog, a presser-foot yieldingly opposed to work-engaging movements of said feed-dog, a presser-foot carrying bar, a presser-bar bearing providing for endwise sliding movements of the presser-bar thereupon, and means disposed for engagement with said presser-bar between said bearing and presser-foot and acting to oppose lateral thrust of the presser-bar upon said bearing.

7. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a four-motion feed-dog, a presser-foot yieldingly opposed to work-engaging movements of said feed-dog, a presser-foot carrying bar, a presser-bar bearing providing for endwise sliding movements of the presser-bar thereupon, and a roller supported for bodily adjustment in a direction opposed to the direction of feed and into ment by said presser-bar.

8. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a four-motion feed-dog, a presser-foot yieldingly opposed to position for engage-' work-engaging movements of said feed-dog, a presser-foot carrying bar, a presser-bar bearing providing for endwise sliding movements of the presser-bar thereupon, anti-friction thrust-absorbing means, and spring means yieldingly urging said thrust-absorbing means into engagement with said presser-bar.

9. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a four-motion feed-dog, a presser-foot yieldingly, opposed to work-engaging movements of said feed-dog, a presser-foot carrying bar, a tubular bearing in which said presser-bar is journaled for endwise movement, a bracket carried by said bearing, and a thrust-absorbing roller journaled upon said bracket for engagement by said presser-bar to thereby oppose lateral thrust of the presser-bar upon said bearing.

10. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a four-motion feed-dog, a presser-foot yieldingly opposed to Work-engaging movements of said feed-dog, a presser-foot carrying bar, a tubular bearing in which said presser-bar is journaled for endwise movement, a bracket carried by said bearing, a thrust-absorbing roller journaled upon said bracket for engagement by said presser-bar to thereby oppose lateral thrust of the presser-bar upon said bearing, and means providing for bodily adjustment of said roller relatively to said presser-bar.

11. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a fourmotion feed-dog, a presser-foot yieldingly opposed to work-engaging movements of said feeddog, a presser-ioot carrying bar, a presser-bar bearing providing for endwise sliding movements of the presser-bar thereupon, a roller journaled for engagement with said presser-bar in a direction opposed to the direction of feed, pivotal supporting means for said roller, and. spring means acting upon said supporting means to yieldingly hold said roller in engagement with said presser-bar to thereby oppose lateral thrust of the presser-bar upon said bearing under the action of said feed-dog.

12. In a sewing machine, stitch-forming mechanism, a work-support, means for advancing work upon said work-support including a fourmotion feeddog, a presser-foot yieldingly opposed to work-engaging movements of said feeddog, a presser-foot carrying bar a presser-bar bearing, a spring tensionally opposing lateral thrust of said presser-bar upon said bearing in the direction of feed, and means for adjusting the tension of said spring.

GEORGE A. FLECKENSTEIN.

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