US2241230A - Sewing machine - Google Patents

Description

y 6, 1- A. L. WILMOTH 2,241,230

SEWING MACHINE Filed July '7, 1957 4 Sheets-Sheet l W1 TNESSES: INVENTOR:

firihurL- mlmoih y 6; 1941- A. L. WILMOTH 2,241,230

SEWING MACHINE Filed July '7, 1957 4 SheetsSheet 2 I'V1 'IINESSES; I NV ENTOR firihur L- Wilmoih,

A TTORN E YS y 1941- A. 1.. WILMOTH 2,241,230

SEWING MACHINE Filed July '7, 1957 4 Sheets-Sheet 3 WITNESSES INVENTOR:

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May 6, 1941. L. WILMVOTH SEWING MACHINE I 4 Sheets-Sheet 4 Filed July '7, 1957 FIG; QET

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I By TTORNEYS.

Patented May 6, 1941 snwmc MACHINE Arthur L. Wilmoth, San Francisco, Calif., assignor to Union Special Machine Company, Chicago, 11]., a corporation of Illinois 1 Application July 7, 1937, Serial No. 152,381

This invention relates to sewing machines; and it has reference more particularly to sewing machines intended for operation upon pile fabrics such, for example, as velours and the like, used in the upholstering of automobiles. Such material is ordinarily coated at the back with latex for anchorage of the pile, and in being seamed in a sewing machine, layers thereof are superimposed one upon another with their pile faces facing each other so that when'the united layers are subsequently turnedoutward, the. stitches of the seams are entirely concealed. Considerable difliculty has been experienced with feeding of latex-backed fabrics, placed as pointed out, in an ordinary sewing machine due to retardation of the upper layer by friction between the tacky latex backing of the latter and the presser foot of the machine. Attempts were made heretofore to overcome this diiiiculty with the aid of a freely supported non-driven endless belt guided to pass beneath the presser foot and thereby prevent direct contact of the latter with the back of the upper layer of the material, but this expedient has proved to be only partially satisfactory.

The chief aim of my invention is to provide for the positive feeding of the uppermost layer of the material concurrently with advance of the lowermost layer by the usual feeding instrumentality of the sewing machine. This desideratum I attain as hereinafter more fully explained through provision of-a slip drive means whereby a belt such as above referred to is caused to advance the upper layer of the material during the active periods of the feeding element of the sewing machine but permitted to be held quiescent by friction with the backing of the uppermost layer during the inactive periods of said feeding element.

Other objects and attendant advantages will appear from. the following detailed description of the attached drawings wherein Fig. I is a longitudinal elevation of a sewing machine embodying my invention.

Fig. II shows the front or head end of the machine in elevation.

Fig. III is a detail cross section on a larger scale taken as indicated by the arrows III-III in Fig. I.

Fig. IV is a fragmentary detail view in plan similarly on a larger scale looking as indicated by the arrows IVIV in Fig. II.

Fig. V is a detail sectional view taken as indicated by the arrows VV in Fig. I; and

Fig. VI is a fragmentary detail view looking as indicated by the arrows VI-VI in Fig. V.

The machine'chosen for convenience of illustrating my invention has a horizontal plate like work support I suitably sustained at an elevation above the base 2 of the machine frame. Extending forwardly from an integral standard or upright I at one end of the base 2 is an am 4 which over-reaches the work support I and which, as usual, terminates in a head 5 wherein a needle bar 6 carrying the needle 1, and the presser bar I carrying the presser foot 9 of the sewing machine are guided for vertical movement. Journaled in suitable bearings beneath the work support is the longitudinally extending main or drive shaft ill of the machine which is fitted at one end with -a combined hand and belt wheel I I, and from which, through interposed connections (not shown) within the hollows of the frame, the needle bar 6 is actuated in a 'well known manner. The illustrated machine also has a four-motion feed dog I 2 arranged directly beneath the presser foot 9 to engage the back of the lower layer L (Figs. V and VI) of the pile material which is to be sewed, from beneathand to intermittently advance it on the work support I relative to the needle I. As usual,

the feed dog I 2 is mounted on a carrier bar l3 which receives its back and forth or feeding movements and its up and down or lifting movements from the main shaft of the machine, through the mechanism comprehensively desig nated by the numeral l4 in Figs. I and II.

For the purpose of assisting the feeding of the material in a machine of the kind briefly described up to this point, I have provided auxiliary means as follows:

Trained for travel around the needle head 5 is a relatively thick endless belt l5 preferably in the form of a tape closely woven from hard twisted textile yarn, as conventionally shown in Figs. V and VI,,said belt being confined to travel in a predetermined path by a series of spool-like idler pulleys I6, I! and I8 supported with capacity for free rotation individually by a T-shaped bracket l9 secured to the top of said needle head by a screw bolt 20, see Figs I and II. From Fig. II, it will be observed that the belt l5 passes under the presser foot 9 whereof the ends are rounded as at 2| and 22 and the bottom surface longitudinally recessed or grooved as at 23 to facilitate movement of the belt and to guide it. From Figs. I, V, and VI, it will be further observed that the depth of the groove 23 in the presser foot 9 is less than the thickness of the For the purpose of driving the belt, Ihave pro'- vided means including a pair of opposing circumferentially- corrugated nip rolls 25, 26 which are disposed at an elevation above the work support I and which engage said belt respectively at I opposite sides. As shown in Fig. I, the shaft 21 of the nip roll 25 is substantially co-extensive in length' with the over-reaching arm 4 of the machine frame and journaled at its ends in bearings afflxed to one side of said arm. The shaft 28 of the other nip roll 26, on the other hand, is journaled in a bearing 29 at the free end of an arm 30 which is pivoted at 3| on a bracket 32 secured to the corresponding side of the head 5 by a pair of screws 33. A helical tension spring 34 whereof one end-is engaged with a fixed anchorage 35 on the bracket 32 and the other end with a screw 36 on the arm 30, serves to keep the nip roll 26 yieldingly in engagement with the belt i5 so that the latter is pinched between the corrugated peripheries of said roll and the companion nip roll 25. This arrangement permits the roll 26 to be moved away from the belt l5 by moving the arm 30 outward about its pivotal connection 3| with the bracket 32 in which position said arm is locked. through engagement of a stud projection 31 thereon with a notch 38 in the side of a latch lever 39 fulcrumed for pivotal movement abouta screw 46 on the bracket 32, see Figs. 11 and IV. A coiled tension spring 4| (Fig. IV) to which the latch lever 39 is subject, tends to yieldingly maintain the notch 38 of said lever 39 engaged with the stud 31 on the roll carrying arm 30. By slight lateral pressure on the latch lever 39 against the pull of the spring 4|, the arm is released and drawn inward by the spring 34 to return the nip 'roll 26 to its normal position in engagement with the belt l5.

Secured to the shaft 21 of the nip roll 25 adjacent the bearing bracket 42 is a pulley 43 of small diameter with a circumferential V-groove; and extending between said pulley and a similar pulley 44 of the same size at one end of a counter shaft 45 at a level below the work support I, is a tensioned coil spring belt 46, said counter shaft being journaled in a bracket 41 secured by screws 49 to the base 2 at the side of the machine frame, Aflixed to the other end of the counter shaft 45 is a V-groove pulley 49 much larger than the pulleys 43, 44 and which is connected by another tensioned coil spring belt 50 with a somewhat smaller V-groove pulley 5| on the drive shaft ID of the machine (see Figs. I and I11), the latter pulley being split for convenience of ready mounting on said drive shaft.

In practice, the belt I5 is maintained under light tension so as to slide freely within the groove 23 of the presser foot 9, its tension being regulatable by adjusting the stud axis 52 for the idler pulley I! (see Fig. II) up or down in a vertical slot shown at 53 in the T-bracket 9. When necessary, due to stretch and accumulation of slack in the belt, the stud axes 54 and 55 of the idler pulleys l6 and I8 may be transferred respectively to other holes 56 and 51 provided for them in the T-bracket |9 in a manner readily understandable from Fig. II.

' During the operation of the machine, as the feed dog |2 moves forward on its active or feedin'g stroke in the direction of the arrow in Fig. 11 to advance the lower layer L of the pile material on the work support I, the belt |5 concurrently advances the upper layer L of said material, said belt slipping easily on the smooth hard under surface of the presser foot 9 since it is under very light tension as above explained. During the retractive strokes of the feed dog l2, and while the needle is in the fabric, however, the belt I5 is held quiescent through friction with the rubberized backing of the upper layer L' of the material thereby reacting upon the nip rolls 25, 26 and temporarily preventing their rotatiomthis being permitted through ability of the spring belt 46 to slip in the grooves of the pulleys 43, 44 which, as previously pointed out are of a small diameter much less than that of the pulleys 49 and 5| for the spring belt. It is to be noted, however, that even though held quiescent during the idle periods of the feed dog,

the belt is maintained under constant driving tension.

By. properly proportioning of the pulleys 43, 44, the auxiliary feeding means of my invention can be adapted to function as explained for any desired stitch length to which the sewing machine is adjusted. Moreover, by reason of the fact that the portion of the belt IS in the intrval between the rear end 22 of the presser foot 9 and the nip rolls 25, 26 is maintained under a constant predetermined tension, any slackarising through movement of the presser foot incident to passage thereunder of cross seams or the like in the material, will be instantly taken up.

Having thus described my invention, I claim:

1. A sewing machine comprising a work support; a needle operated from above the work support; feeding means for engaging the fabric from beneath and intermittently advancing it on the work support relative to the needle; a presser foot operative to hold the material down on the work support; and auxiliary feeding means including an endless belt which runs under the presser foot and engages the material' from above, a pair of opposing nip rolls respectively engaging the belt from opposite sides, a rotary shaft, and a slip belt of coiled spring wire connecting a circumferentially-grooved pulley on the drive shaft with a similar pulley on the shaft of one of the nip rolls.

"2. A sewing machine comprising a work support; a drive shaft journaled beneath said work support; a needle operated from above the work support; feeding means for engaging the material being sewed from beneath and advancing it on the work support relative to the needle; a presser foot operative to hold the material down on the work support; and auxiliary feeding means including an endless belt which runs under the presser foot and engages the material from above, a pair of nip rolls respectively engaging the belt from opposite sides, a rotary counter shaft Journaled beneath the work support and driven .from the drive shaft aforesaid, and a spring wire coii slip belt connecting a 'circumferentially-grooved pulley on the counter shaft with a similar pulley on the shaft of one of the nip rolls.

3. A sewing machine comprising a work support; a drive shaft Journaled beneath said work support; a needle operated from above the work support; feeding means for engaging the material being sewed from beneath and advancing it on the work support relative to the needle; a presser foot operative to hold the material down on the work support; and auxiliary feeding means including an endless belt which runs under the presser foot and engages the material from above, a pair of nip rolls respectively the belt from opposite sides, a rotary counter shaft journaled beneath the work support, a drive belt connecting a pulley on the counter shaft with a pulley on the drive shaft aforesaid, and a spring wire slip belt connecting a circrunferentiallygrooved pulley of smaller diameter on the colmter shaft with a similar pulley on the shaft of one of the nip rolls.

4. A sewing machine comprising a work support with an over-reaching arm; a drive shaft journaled beneath the work support; a needle bar with a needle guided for vertical reciprocation in a head at the free end of the over-reachingarm; feedingmeansfor thematerial being sewed from beneath and it along said work support relative to the needle; a presser foot operative to hold the material down on the work support; and auxiliary feeding means including an endless belt which runs under the presser foot and engages the material from above, means defining a circuit for the belt around the head of the over-reaching arm; a pair of nip rolls at an elevation above the work support respectively the belt from opposite sides; shafts respectively for said nip rolls journaled in bearings on the overarm of the machine frame, a counter shaft journaled at a level beneath that of the work support in parallel relation to the drive shaft aforesaid, a horizontally-arranged belt connecting a pulley on the counter shaft with a pulley on the drive shaft aforesaid, and a vertically-arranged wire coil slip belt connecting a circmnferentiallygrooved pulley of smaller diameter on the counter shaft with a similar pulley on the shaft of one of the nip rolls,

5. A sewing machine for uniting, while arranged face to face, two layers of pile fabric or the like having a frictional backing, comprising a work support; a reciprocating needle; intermittent feeding means operative at the stitch point for engaging the back of one layer of the material to intermittently shift it on the work support relative to the needle; auxiliary feeding means including an element with a continuous rough-surface for eng n the back of the second fabric'layer opposite the intermittent feeding means at the stitch point; and slip drive means for actuating the auxiliary feeding element to effect synchronous advance of the second layer with the first during the active periods of the intermittent feeding means, but allowing said auxiliary feeding means to remain quiescent in contact with said second layer during the inactive periods of said intermittent feeding means.

6. A sewing machine for uniting, while arranged face to face, two layers of pile fabric or the like having a frictional backing, comprising a work support; a reciprocating needle; intermittent feeding means operative at the stitch point for engaging the back of one layer of the material from beneath to intermittently shift it on the work support relative to the needle; and auxiliary feeding means including an element with a continuous rough-surface for engaging the back of the second fabric layer from above opposite the intermittent feeding means at the stitch point; and slip drive means for actuating said auxiliary feeding element to effect synchronous advance of the second layer with the first during the active periods of the intermittent fading means, but allowing said auxiliary feeding means to remain quiescent in contact with the material during the inactive periods of said intermittent feedings means.

I. A sewing machine for uniting, while ar ranged face to face, two layers of pile fabric or the like having a frictional backing, comprising a work support; a needle operated from above the work support; intermittent feeding means operative at the stitch point for engaging the back of one layer from beneath to intermittently shift it on the work support relative to the needle; a presser foot operative to hold the material down on the work support at the stitch point; auxiliary feeding means including a rough surfaced endless belt which under-travels the presser foot and engages the back of the other layer from above opposite the intermittent feeding means; and slip drive means for actuating the belt to effect synchronous advance of the second layer with the first, but allowing the belt to dwell with the material during the idle periods of the intermittent feeding means.

8. A sewing machine for uniting, while arranged face to face, two layers of pile fabric or the like having a frictional backing, comprising a work support; a needle operated from above the work support; intermittent feeding means operative at the stitch point for engaging the back of one layer from beneath to' intermittently shift it on the work support relative to the needle: a presser foot for holding the material down on the work support at the stitch point; auxiliary feeding means including an endless rough-surfaced belt for engaging the back of the other layer from above at the stitch point opposite the intermittent feeding means, said belt being confined to traversea longitudinal guide groove in the bottom surface of the presser foot; and slip drive means for actuating the belt to effect synchronous advance of the second layer with the first, but allowing the belt to dwell with the materlai during the idle periods of the intermittent feeding means.

9. A sewing machine for uniting, while arranged face to face, two layers of pile fabric or the like having a frictional backing, comprising a work support with an over-reaching arm; a needle bar with a needle confined to vertical reciprocation in a head at the free end of said arm; intermittent feeding means operative at the stitch point for engaging the back of one layer of the material from beneath to. intermittently shift it on the work support relative to the needle; a presser foot for holding the material down on the work support at the stitch point; auxiliary feeding means including an endless rough-surfaced belt which runs under the presser foot at the stitch point and contacts with the back of the second layer opposite the intermittent feeding means, and means defining a circuit for the belt around the head of the over-reaching arm; and slip drive means for actuating the belt to effect synchronous advance of the second layer with the first, but allowing the belt to dwell with the material during the idle periods of the intermittent feeding means.

10. A sewing machine for uniting, while arranged face to face, two layers of pile fabric or the like having a frictional backing, comprising a work support with an over-reaching arm; a

which runs under the presser toot at the stitch 10 pointand ensues the-other lavertrom above.

opposite the intermittent i'eedin: means, and a series of spaced rollers defining a circuit for the belt around the head on the over-reaching arm: and slip drive means for actuating the belt to eil'ect synchronous advance of the second layer with theflrst. butallowlng thebelt todweil with the material during the idle periods'o! the intermittent feeding means.

ARTHUR L. WIIMOTH.

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