US2097246A - Sewing machine - Google Patents

Description

Oct. 26, 1937. N. v. CHRISTENSEN SEWING MACHINE Filed June 8, 1955 2 Sheets-Sheet 1 INVENTOR:

mmanVLhrisfan/smy BY W W M Oct. 26, 193?. N. v. CHRISTENSEN SEWING MACHINE Filed June 8, 1935 2' Sheets-Sheet 2 INVELNTO'R: NOMnanI Ch 5213215571 Z/WITNIE'SSES: v

A-TJ'TORNEYS.

Patented Oct. 26, 1937 UNlTED STATES SEWING MACHINE Norman V. Christensen, Chicago. 111., assignor to Union Special Machine Company, Chicago, 111., a corporation of Illinois Application runs a, 1935, Serial No. 25,590 1 Claim. (01. 112-220) This invention relates to sewing machines, and particularly to sewing machines of the rotary hook type.

In sewing machines of 'the rotary hook type,

5 a rotating ratio of 2:1 is usually provided between rotary hook and feed operating shafts disposed beneath the work plate of the machine.

This is because the feed must operate with every stroke of the needle, while the rotary hook must rotate two or more times for every such stroke. It is an object of my invention to provide simple, compact, and reliable, drive means between the feed shaft and rotary hook shaft to produce this ratio, the drivemeans being of such character as to permit operation of the machine'at much higher speeds than ordinarily, with attendant lessening of noise and vibration, and

to simplify materially the matter of lubrication of rotating parts.

Heretofore it has been proposed to house the mechanism for transmitting power from the main shaft to the feed shaft of a sewing machine within a closed standard, and'thus to seal these parts effectively for the purpose of lubrication, and to employ additionally a separate sealed casing for housing a gear transmission betweenthe feed shaft and rotary hook shaft. An important advantage of the present invention is that it dispenses with the necessity for employing such a separate casing for housing a gear transmission between the feed shaft and rotary hook shaft, with the result that all of the power transmitting mechanism requiring lubrication is confined to the interior of the hollow standard.

As an example of my invention, I have shown a sewing machine in which a transmission shaft beneath the work plate of the machine for actuating the feed element rotates in unison with the main shaft by which the needle is operated; and from this feed shaft rotation is imparted to a countershaft upon which the rotary hook is mounted. The invention is also applicable to a reverse arrangement in which the transmission shaft is driven at a higher rate of speed, with the rotary hook mounted thereon and the proper reduced rate of rotation imparted to a countershaft by which the feed is operated.

Other objects and advantages of my invention in side elevation and of a sewing machine embodying the present improvements.

will be manifest from the following description,

Fig; 11 is a transverse section, taken as indlcated by the arrows II'-II in Figsz-I and III;

and

Fig. 111 is a fragmentary staggered plan sectional view, takenas indicated by the arrows III-III in Fig. I.

In these illustrations, the numeral l designates the work support of the machine from which rises, at one end, a hollow standard 2 with an integral tubular horizontal am! overreaching said work support. Suitably journaled within the hollow arm 3 is the main drive shaft 4 of the machine, said drive shaft being fitted at the rear end with a hand wheel 5, and a pulley 6 adapted to be connected by belt with a motor or other source of powers Vertically reciprocating in a head I at the end of the overhanging arm 3 is a needle bar 8 which car ries a seaming needle 9, and which, through suitable connections (not illustrated) is actuated from the main drive shaft 4. At l0 there is shown a'take-up member for the needle thread (not illustrated), which member may also be actuated in a -well-known manner through suitableeonnections with the main shaft The head I, moreover, affords vertical guidance to a presser bar ll which, at itslower end, carries a presser foot 12 of ordinary construction.

Extending longitudinally of the machine below the work support I is a transmission shaft I3, which, at its front end, is journaled in a bushing ll secured in a pendant bearing lug I5 of the work support I. The rear end of the transmission shaft !3 extends through a bearing bushing it into an oil well I'l. Secured to said shaft within the chamber i1 is a spur gear l8, preferably formed from non-resonant material such as bakelite, and provided with a metallic hub. The wheel I8 constitutes one element of a gear train which includes idler gears I9, 20, and a drive gear 2| secured to the main shaft 4. The gears l9 and 2| may be wholly of metal, while the gear 20, like the gear I8 is preferably made from bakelite and provided with a metallic hub. The gear wheels I8, 20 are supported for free rotation between collars 22,, 23, respectively on pins 24, 25 suitably secured against rotation in opposite side walls of the hollow standard 2 which houses the gear train. As shown, the gear wheel I! dips into the oil within the well l1, and, in rapid rotation, splashes the gear wheels is, 20 and 2|. The splash lubricant falling upon the gears I9, 20 finds its way through apertures 28, 2'! in the collars 22, 23 to spiral oil distributing grooves 22, 22 internally transmission shaft I8 is driven in unison with the main driving shaft.

Secured to the transmission shaft I3 (Fig. III) adjacent the bearing II, is a rotary member 42, which, through an arm 33 on a rock shaft 34 journaled in fixed lugs 35 on the work support I, actuates the feed element 34 of'the machine.

By virtue of the described arrangement, the feed element 36 is actuated once foreach reciprocation of the needle bar I.

Also journaled in a pendant bearing 31 of the work support I is a countershaft II which parallels the transmission shaft II, and which, at its' front end, carries a rotary hook I. to cooperate with the seaming needle I. Tothe inner end of the rotary hook shaft 34 is secured a small toothed wheel 40 which is coordinated by an endless flexible belt 4| of, leather, woven fabric, or the like, having equi-spaced projections 4 la, with a larger toothed wheel 42 fast on the transmission shaft I3. The diametral ratios of the toothed wheels 40, 42 is one to two so that the'rotary hook shaft I8 is driven at twice the speed of said transmission shaft l3, and it therefore makes two revolutions during each actuation of the needle I and the feed element 38, as required. If desired or found convenient in practice, a "silent" sprocket chain may be substituted for the belt 4|.

As an alternative, the wheels or the gear train it-fi may be proportioned to drive the transmission shaft it at twice the speed of the needle actuating or main shaft 4, and the rotaryhook 3| mounted directly on said transmission shaft. Under these circumstances, the rotary actuating member 32 for the feed element 3! is mounted on a countershaft, and the position of the toothed wheels", 42 reversed to determine rotation of said countershaft at half the speed of the transmission shaft for actuation of the feed element in unison with the needle I as before.

According to the preferred practice of my invention, the projections 4la onthe belt 4| are of such number, with relation to the notches of the wheels; 42, that the wear between these means lost motion between the feed shaft l3 and the rotary hook shaft 38. The close proximity of these shafts is a further factor in insuring the maintenance of the proper timed relation between the shafts.

It will 'be noted that the use of the flexible drive of this invention eliminates the necessity of employing an additional casing to house the transmission between the feed shaft and rotary shaft, for the flexible belt requires no lubrication and may be exposed beneath the work support.

From the foregoing, it will be seen that, in addition to being simple and efficient, the transmission of my invention is advantageous because it favors noiseless and vibrationiess operation of the sewing machine at high speeds, simplifies materially the matter of lubrication, and at the same time insures proper timed relation between the feed'shaft and rotary hook shaft.

Having thus described my invention, I claim:

In a sewing machine, a work support with an overhanging arm; a needle; a rotary needleactuating shaft supported by said arm; a needle actuated from said shaft; feeding means with an actuating shaft therefor also beneath the work support; a rotary hook and a shaft therefor beneath the work support; 'andmeans whereby the feed-actuating and the rotary hook shafts are driven'in the same direction but oppositely to the needle actuating shaft, including a belt connecting. sprockets respectively on said rotary hook and feed-actuating shafts, spur gears respectively on the needle and the feed actuating shafts,,and a plurality of interposed intermeshing idler gears connecting saidv spur gears.

NORMAN V. CHRISTENSEN.

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