US2124033A - Sewing machine mechanism - Google Patents

Description

July 19, 1938; J. F. HAND SEWING MACHINE MECHANISM.

I Fi1ed April 1, 1936 3 Sheets-Sheet 1 INVENTOR.

Hand,

2W BY July 19, 1938. J. F. HAND SEWING MACHINE MECHANISM :5 Sheets-Sheet '2 Filed April 1, 1936 INVENTOR. rib Ian 17 Hand,

ATTORNEY.

July 19,- 1938.

J. F. HAND SEWING MACHINE MECHANISM Filed Afiril 1, 1956 s Sheets-Sheet s Y a m Mam n F Patented July 19, 1938 PATENT OFFICE SEWING MACHINE MECHANISM John F. Hand, Philadelphia, Pa assignor to The De Long Hook and Eye Company, a corporation of Pennsylvania 3 Application April 1, 1936, Serial N... 72,036

Claims.

The invention relates to sewing machine mechanism and involves various improvements for automatically adjusting the work feeding device in order to adapt such mechanism for making 5 stitches of variable length at predetermined intervals in the stitching operation. The invention has for one of its principal objects the provision of an elongated stitch at reguiar intervals in a line of stitches otherwise of w uniform length. One of the intended purposes of such elongated stitches is the provision of gaps in a line of stitching used for securing two pieces of fabric togethenso that these gaps mat be utilized to receive the hooked ends of hook fastener devices when fastener tape with such fastener devices thereon is secured to the edge of the stitched material. This object of themvention is accomplished by the provision of .mechanism for periodically increasing the extent 29 of feed of thevwork as, predetermined stitches are formed.

The invention has for a further object the provision of improved mechanism for periodically varying the extent of movement of the intermittent feeding means of a sewing machine. As disclosed herein, the improvements are incorporated in a sewing machine of the type in which a link-bar is utilized for providing intermittent feeding movement of the feeding device. A par- 30 ticular object of the'invention, therefore, is the provision of improved mechanism for periodically adjusting the fulcrum of this link-bar to thereby vary the extent of movement of the feeding device at each intermittent operation 85 thereof.

A further object of the invention is the provision of means for eilecting manual adjustment of the elongated stitches with respect to the stitches of normal length in the line of stitching.

49 A still further object of the invention is the provision of novel means for effecting manual adjustment of the extent of movement of the work feeding device to thereby vary the length of all the stitches in the line of stitching.

Still further objects and advantages of the various features of the invention will be apparent from the following description,.taken with the accompanying drawings wherein:

Fig. 1 is a front elevational view of a sewing 50 machine with the improvements incorporated therein, parts of the machine being broken away for clarity;

Fig. 2 is a plan view of the machine shown in Fig. 1, with the overhanging bracket arm broken Fig. 8 is a horizontal sectional view of the machine shown in Fig. 1, takeFiiistbelow .thebase plate, and showing the work feed device in plan view;

Fig. 4 is a vertical sectional view of the ma- 5 chine taken on the line 4-4 of Fig. 1;

Fig. 5 is a vertical sectional view of the machine taken on the line 5-5 of Fig. 1;

Fig. 6 is a vertical sectional view of the machine taken on the line 65 of Fig. 1;

Fig. 7 is an end elevational view of the brake mechanism for the cam shaft of the improved mechanism, the cam shaft being shown in crosssection;

Fig. 8 is a plan view showing a sectionof two pieces of material stitched together with the improved feed mechanism; and

Fig. 9 is a perspective view illustrating the manner in which the operative portons of hook fastener elements may be inserted through the gaps in a line of stitching made with the improved mechanism.

As illustrated in the drawings, the present improvements are incorporated in a sewing mechine having the usual bed plate iii upon one end v of which is mounted the hollow standard it carrying the overhanging bracket arm i2 upon the outer end of which the head it is supported. A needle bar M is mounted for reciprocating movement in the head l3, and a presser foot bar i5 carrying a presser foot 86 is supported in the head in a manner permitting it to be raised and lowered by means of the presser foot lever ii. c Any well-known means may be employed for reciprocating the needle bar it from the main drive shaft I8 supported in suitable bearings in the standard ii and the bracket arm i2. Continuous rotary movement of the drive shaft i8 is provided by means of a pulley i9 secured on the outer end thereof and to which power may be 40 transmitted by a belt from any suitable source.

As disclosed herein, the improvements are utilized with an intermittently actuated feeding device comprising a feed dog 20 secured upon a feed bar 2!. The teeth of the feed dog 20 project upwardly through suitable slots in a feed plate 22 during the operation of advancing the work w to the stitch forming mechanism comprising the needle 23 and the loop forming device 24.

Horizontal reciprocating movements of the feed bar 2| are provided by means of a rock shaft 25 supported at its opposite ends upon bearing screws 26 adjustably threaded in bearing .mem-

bers 21 projecting downwardly from the base plate III. The rear end of the feed bar 2| is pivotally connected to spaced rocker arms 23 on the rock shaft 25 by means of a pair of bearing screws 23 threaded in the arms 23.

The vertical movements of the feed bar 2| are provided, by means of a rock shaft 33 beneath the front edge of the base plate l0 and having its opposite ends supported upon bearing screws 3| adjustably threaded in bearing members 32 projecting downwardly from the base plate ill. The end of the rock shaft 30 adjacent the feed bar 2| is provided with a rocker arm 33 having an anti-friction roller 34 mounted on the outer end thereof for cooperation with a slot 35 in the forward end of the feed bar so that rocking movements of the rock shaft 30 operate to raise and lower the forward end of the feed bar and thereby bring the feed dog 20 into and out of work feeding position in a manner well understood in the art.

Rocking movement of the rock shaft 30 is produced by means of an eccentric rod 33 having its lower end pivoted to the free end of an arm 31 on the rock shaft 30 and its upper end connected to an eccentric strap 38 which encircles an eccentric 33 on the drive shaft l8. Rocking movement is given to the rock shaft 25 by a link-bar-4ll the lower end of which is pivoted to the free end of a rocker arm 4| on the rock shaft 25 and the upper end of which is in the form of a yoke 42 forming a guideway for a cross-head 43 actuated by an eccentric 44 on the drive shaft l8.

Thelink-bar is fulcrumed on the upper end of a link 45 the lower end of which is pivotally secured to the outer end of one arm 43 of a bellcrank adjusting lever 41. The lever 41 is pivotally supported on the standard II by means of a screw 48, as shown in Figs. 1 and 2 of the drawings. In machines of this general character the bell-crank lever 41 is commonly adjusted into different positions by means of a set screw extending outwardly from the lever arm 49 through a slot 50 in the standard II, the lever 41 being retained in any desired position by engagement of the head of the adjusting screw with the edges of the slot 50. As is well understood, adjustment of lever 41 operates, through the link 45, to move the fulcrum of link-bar 4U nearer to or further from the axis of the shaft l8, and thereby decrease or increase the extent of feeding movement of the feed-dog 20.

In accordance with the present improvements, the usual'manual adjusting screw for lever 41 is replaced by a short rod 5| having its inner end threaded in the arm 49 of the adjusting lever. The outer end of rod 5| is provided with a head 52 pivotally connected to the upper end of a turn-buckle structure 53 forming a part of a cam rod by means of which motion is transmitted periodically to the lever 41 for the purpose of efiecting adjustment of the fulcrum of the linkbar 40. The lower end of the turn-buckle strucmm 53 is pivotally connected to the upper end of a slide bar 54 operating in a guide member 55 the lower end of which is secured to the base plate ID.

A cam roller 53 is mounted on the outer end of a pin 51 secured on the'slide bar 54 and cooperates with the cam surface of a plate cam 58 secured on one end of a cam shaft 59 extending parallel with the drive shaft l8. The cam shaft 59 is suitably supported in the upper end of bearing brackets 30 secured to the base plate [0 and extending upwardly therefrom.

The cam shaft 59 is intermittently rotated by means of a ratchet wheel 3| secured thereon for cooperation with an actuating pawl 32 pivoted on the outer end of one arm 33 of a bell-crank lever 34 freely movable on the cam shaft 59. The free end of the pawl 32 is maintained in engagement with the ratchet wheel 3| by a split leaf spring 35 having one end portion secured to the arm 33 and. the other end portion in engagement with the pawl 32.

The arm 33 of the bell-crank lever 34 is provided with a pin 31 to which one end of a" pitman 38 is connected. The opposite end of the pitman 33 is connected to a disc 39 on one end of a stub shaft 10 by means of a crank pin II. The stub shaft 10 is suitably supported in a bearing block 12 secured on the upper side of the base plate Ill.

The stub shaft 10 is rotated by means of a set of worm gears 13, 14, the former being secured on the stub shaft and the latter being secured to -a vertical shaft I5. The lower end of vertical shaft I5 has a bearing support in the bearing block 12 and the shaft is supported near its upper end in a bearing bracket 13 secured to the under side of the bracket arm I2. The upper end of shaft 15 extends into the bracket arm l2 through an opening. 11 and has fixed thereon a bevel gear I8 which meshes with a corresponding bevel gear I9 on the drive shaft l8.

As will be apparent from the structure heretofore described, the continuous rotary motion of the drive shaft I8 is transmitted directly to the vertical shaft 15, thence to the horizontal stub shaft 10, and intermittent rotary motion is thereupon imparted to the cam shaft 59 through the pitman 68, the bell-crank lever 34, the pawl 32 and the ratchet wheel 6|. Preferably the number of teeth upon-the ratchet wheel 3| corresponds to the number of stitches made by the stitch forming mechanism during each complete rotation of cam shaft 59. As illustrated in the drawings, the mechanism has been designed for a cycle of eight stitches, seven being of normal length as shown by a in Fig. 8, and the eighth stitch being elongated, as shown by b, for the purpose of forming a hook receiving gap.

The manner in which the elongated stitch bis formed will be clear, to those skilled in the art, from the operation of the structure heretofore described. It will be noted, however, that the projection on the cam 58 is so designed as to pass by the cam roller 53 during a single actuation of the pawl 32. During this interval, that is, in the interval during which the cam roller 53 is passing over the projection on the cam 58, the adjusting lever 41 is so actuated as to move the fulcrum of the link-bar 40 away from the axis of the shaft l8 to thereby increase the throw of the lower end of the link-bar 40 and consequently increase the extent of movement of the feed dog 20 between two consecutive reciprocations of the needle bar I4. As a result/the particular stitch then being made will be elongated to an extent determined by the design of the cam 53 and the adjusting lever 41.

The illustrated mechanism therefore provides a simple automatic means which is positively actuated by a moving part of the machine for periodically adjusting the fulcrum of the link-bar and thereby varying the extent of movement of the feed, dog at predetermined intervals without disrupting the operation of the machine in the formation of intervening normal stitches. It will also be apparent to those skilled in the art that manual rotation 'of the nut of the turn-buckle structure 53 provides a simple means for manually adjusting the length of all the-stitches in attached to a tape f formed of a folded strip: of suitable material.

the line of stitching. Inasmuch as rotation of the turn-buckle nut inone direction operates to lengthen the cam rod, and rotation of this nut' in the opposite direction'operates to shorten the cam rod, rotation of this nut in one direction or the other will effect a permanent setting of the adjusting lever 41 to thereby increase or decrease the extent of feeding movement of the feed dog 20 as may be desired. I

The cam roller 58 is maintained in contact with the surface of the cam 58 by means of a coiled spring the lower end of which is secured to a pin 8i, such as the pivot pin between the slide bar 54 and the turn-buckle structure 53, and the upper end of which is secured to the angularly bent end of a supporting rod 82 having its lower end secured to the base portion of the guide member 55..

The cam shaft 59 is preferably provided with a. brake device .83, as shown in Figs. 1 and '7, for the purpose of controlling the rotation of the cam shaft, and particularly for preventing reverse rotation thereof. This brake device is preferablyin the form of two semi-circular clamping members 84 surrounding a collar 85 on shaft 59 and having the lower ends thereof mounted upon a common pivot 86 projecting outwardly from one of the upstanding brackets 60. The clamping members 84 are preferably provided with a suitable lining 81, and the desired friction may be secured by the adjustment of a wing nut 88 on a bolt 89 connecting the free ends of the two clamping members. I

One end of the cam shaft 59 is also provided with a milled hand wheel 90 for the purpose of manually rotating the shaft and thereby adjusting the elongated stitches b into the position desired with respect to the work 10. The particular location of the elongated stitches with respect to the work having been determined, it is only necessary to rotate the cam shaft 59 by means of the hand wheel 90 so as to bring the operative portion of the cam 58 into such a position that one of the inclined surfaces thereof is in engagement with the cam roller 56 in order to definitely locate the elongated stitches on the goods. As illustrated in Fig. 6 of the drawings, the operative portion of the cam 58 has just passed by the cam roller 56 and, as a consequence, the link-bar 40 is in position for making normal stitches a of uniform length. Should it'be desired to begin the line of stitching with an elongated stitch b, the cam shaft 59 may readily be rotated by means of the hand wheel 90 so as to bring the advancing edge of the operative portion of the cam 59 into engagement-with the cam roller 56, whereupon the normal operation of the sewing machine will first produce an elongated stitch b followed by seven short stitches a of uniform length, and this cycle will be repeated throughout the line of stitching.

The manner in which two pieces of material such as c and d, sewed together by the machine disclosed herein, may be utilized with the hook elements e of hook and eye fastener devices is illustrated in Figs. 8 and- 9 of the drawings.

When sewed together with the improved mechanism, a line of stitching is formed in which the elongated stitches b occur at regular intervals throughout the normal stitches a. The elongated stitches therefore provide gaps through which the operative portions of the hook elements e may be inserted in the manner illustrated in Fig. 9.

As shown in Fig. 9, the hook elements e are The strips of material 0 and d are folded backwardly over. the line of stitching. and the operative portions of the hook elements e. are inserted through the .gaps. The

extreme edge of the strip d is then preferably turned under the tape 1, whereupon the tape is secured within the folded strips c and d by suitable lines of stitching g. -It will be understood, of course, that the wider strip 0 may be the material of the garment to which the hooks are attached, although in practice it is preferable to attach the tape 1, with the hooks e'thereon, to the separate strips c and 11 which are thereafter secured to the edge of the garment.

It willbe understood that Figs. 8 and 9 of the drawings merely illustrate one use which may be made of the form of stitching produced by the machine disclosed herein, and it will be apparent that such stitching is well adapted for other practical uses where stitches of normal length would not provide gaps of the desired length and it would be necessary to increase the length of predetermined stitches at regular intervals throughout the line of stitching.

While specific forms and arrangements of the various parts of the improved mechanism have been disclosed, it is to be understood that the disclosure is illustrative only and that changes in form and arrangement of the elements may be made without departing from the invention,

the scope of which is to be determined by the appended claims.

What I desire to claim as my invention is:

1. In a sewing machine of the type having a bed plate, a standard and bracket arm mounted thereon, a drive shaftmounted in the bracket arm, and a feed link-bar actuated by an eccentric on the drive shaft and fulcrumed upon one end of a link pivoted at its opposite endto one arm of a bell-crank feedadjusting lever pivoted within the standard, the combination of a cam shaft supported on said bed plate parallel to said drive shaft, transmission means between said drive shaft and said cam shaft to rotate said cam shaft intermittently, a cam on said cam shaft, a cam rod actuated in an endwise direction by said cam, and a lever extension rigidly secured at its inner end'to said feed adjusting lever and projecting outwardly from said standard with its outer end pivoted to said cam rod to periodically vary the extent of movement of the lower end of said link-bar.

2. In 'a sewing machine of the type having a feed link-bar actuated by the drive shaft and fulcrumed upon one end of a link pivoted at its opposite end to one arm of a bell-crank feed adjusting lever, the combination of a cam shaft, transmission means between said drive shaft and said cam shaft to rotatesaid cam shaft intermittently, a cam on said cam shaft, a cam rod actuated in an endwise direction by said cam and including a turnbuckle device to adjust the length thereof, and a lever extension rigidly secured at one end to said feed adjusting lever and pivoted at its other end to said cam rod to periodically vary the extent of movement of the lower end of said link-bar.

3. In a. sewing machine attachment, a cam shaft, a cam. fixed on said shaft, a cam rod ing saidratchet wheel, a stub shait parallel to said cam shaft, a crank on said stub shaft, a pitman operatively connecting said crank and said pawl, and means for transmitting continuous rotary motion from the drive shaft of the sewing machine to saidvstub shaft.

.4. In an attachement for automatically varying the length of the stitch of a sewing machine having a bell-crank feed regulating lever, a pro-- jecting arm secured to said lever, an intermittently rotated cam, a cam rod actuated in an endwise direction by said cam and including a tum-buckle structure for adjusting the length of said rod, and means for pivotally connecting one end of said cam rod to said projecting arm.

5. In an attachment for automatically varying the length of the stitch of a sewing machine having a bell-crank lever for adjusting the fulcrum of the feed link-bar, a cam shaft, a cam fixed on saidcam shaft,a cam rod actuated in an endwise direction by said cam, and having one end thereof pivotally connected to an arm of said bell-crank lever, a ratchet wheel fixed on said cam shaft for rotating the same step-bystep, a. pawl loosely mounted on said cam. shaft for actuating said ratchet wheel, a stub shaft parallel to said cam shaft, a crank on said stub shaft, a pitman operatively connecting said crank and said pawl, means for continuously rotating said stub shaft, a brake for resisting reverse rotation of said cam shaft, and manually operated means for rotating said cam shaft.

JOHN F. HAND.

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