US2025652A - Sewing machine - Google Patents

Description

SEWING MACHINE Original Filed Oct. 51,1934 5 Sheets-Sheet 1 Fig.1;

.. lrivenTor.

Hon"? DuKe ATTys.

Dec. 24, 1935.

H. DUKE SEWING MACHINE Original Filed Oct. 51, 1934 I Fig.2.

3 Shets-Sheet 2 Her \nvenTor.

ATTys.

Dec. 24, 1935. 4 DUKE 2,025,652

SEWING MACHINE K Original Filed 001;. 31, 1934 3 Sheets-Sheet 3 lnve nTorQ 3 Harry DuKe I ATTys.

Patented Dec. 24, 1935 UNITED STATES SEWING MACHINE Harry Duke, Salem, Mass.

Original application October 31, 1934, Serial No. 750,852. Divided and this application March 4.,

1935, Serial No. 9,257

3 Claims.

This invention relates to sewing machines and particularly to the feed mechanism thereof.

While the feed mechanism embodying my invention may be used with different sewing machines, I have herein shown it as it might be embodied in a sewing machine such as is illustrated in my co-pending application Serial No. 750,852, filed October 31, 1934, of which this application is a division.

The object of the present invention is to provide an improved feed mechanism for sewing machines which is relatively simple and which is so constructed that the feed may be adjusted readily while the machine is in operation.

A further object of the invention is to provide various other improvements which will be more fully hereinafter set forth.

In the drawings;

Fig. l is a side view of a sewing machine such as is illustrated in my said co-pending application Serial No. 750,852 and having my improved feed mechanism therein.

Fig. 2 is an end view of the machine shown in Fig. 1.

Fig. 3 is a fragmentary plan view with parts broken out.

Fig. 4 is a fragmentary view showing the means for giving the feed dog its horizontal movement.

Fig. 5 is a fragmentary view showing the means for giving the feed dog its vertical movement.

The sewing machine herein illustrated is an overedge sewing machine of that type having a needle operating above the work and which carries a loop of needle thread through the work, and also having two loopers co-operating with the needle to form the overedge stitches, one looper operating beneath the work and the other looper-having a loop-carrying movement around the edge of the work. The stitch-forming mechanism of the machine shown in the drawings includes the vertically-reciprocating needle I and two loopers 2 and 3. The needle I is carried by the needle bar 4 which reciprocates vertically in the arm 5 of the sewing machine frame 6, said needle bar receiving its reciprocation from an eccentric I carried on the driving shaft 8 of the machine through the medium of a link 9 and a rocker member l journalled in the frame. The lower 1ooper,2 is carried by a rocker member I l which rocks about a shaft l2,.said rocker receiving its ro'cking movement from an eccentric l3 also mounted on the shaft 8. The rocker H is shown as connected by a lever I4 to an arm of another rocker member l which oscillates about the shaft 16, said rocker member being connected to the eccentric strap ll of the eccentric l3.

The looper 3 is carried by a looper carrier l8 which has a stud or follower operating in a cam groove it? in a cam plate 20, the end of the carrier 3 being connected to an arm 2| of a rocker member 22 which in turn is connected by a link 23 to an eccentric 24 on the shaft 8.

The under looper 2 is shown as a threaded looper and is threaded with the under thread or looper thread 25. In the operation of the machine this looper 2 takes each loop of needle thread 26 and inserts through it a loop of the looper thread 25, and the upper looper 3 takes each loop of looper thread and carries it around the edge of the work and presents it in a position to receive the needle on the next penetrating thrust.

The parts thus far described are such as are found in my said co-pending application, Serial No. 750,852 and form no part of my present invention which, as stated above, relates to the feed mechanism for feeding the work.

The feed mechanism is of the usual four-motion type and comprises a feed dog 21 which has both a horizontal movement and a vertical movement, the work W being held against the feed dog during the sewing operation by the usual presser foot 28. This feed dog 2'! is mounted on a carrier 29, and suitable means are provided for giving the carrier the necessary horizontal and vertical components of motion. This carrier 29 is provided with a stud 30 which carries a block 3| received in ways between two horizontallyextending arms 32, 33, said arms serving to guide the carrier 29 in its horizontal movement. The carrier 29 is also provided with a stem 34 which is pivotally connected at its rear end as shown at 35 to the upper end of a rocker 36 which has an oscillating or rocking movement on a pivotal axis 31. The rocker 3'5 is in the form of a yoke and the lower end thereof is connected by an arm 71 toan eccentric strap 38 that embraces an eccentric 39 mounted on the driving shaft 8. The operation of the eccentric oscillates the rock-er member 30 about its pivotal mounting 3'! thereby moving the upper end of the rocker member back and forth horizontally and giving to the feed dog 21 its horizontal reciprocating movement. Although the rocker 30 has an oscillating movement about its pivotal axis 3'l, yet during this oscillating movement the lower end of the rocker moves in a straight or right line. The pivotal connection between the arm 11 and the rocker is through a medium of a bolt 40, and this bolt is provided with two blocks 4|, one at each end thereof which slide back and forth in horizontal ways 42 formed in the base portion 43 of the frame 6.

The eccentric 39 and connection I1, 33 thus give the required horizontal component of motion to the feed dog 21 and during this horizontal movement of the feed dog the block 3! slides back and forth between the arms 32, 33.

The vertical component of the feed motion is secured by oscillating the arms 32, 33 in a vertical direction. For this purpose said arms are shown as carried by a rocker member 44 pivoted at 45 to the base portion 43 of the frame, said rocker having an upstanding arm 46 provided with a forked end M, the arms of which fork embrace a block 48 mounted on a pin 49 extending from the end of the shaft 8 but mounted eccentrically thereon. The operation of the eccentric pin 49 oscillates the rocker 46 and thereby gives the arms 32, 33 a vertical reciprocating motion which is timed properly with the horizontal motion of the feed dog to produce the required four-motion feed.

The length of the stitches which are made is governed by the amplitude of the horizontal movement of the feed dog, and means are herein provided whereby this amplitude of movement can be adjusted or varied while the machine is in operation. The pivotal mounting 31 for the rocker 36 is adjustable vertically thereby to change the relative lengths of the lever arms of said rocker.

Each of the two sides or cheek portions 50 of the rocker '36 is pro-vded with a vertical slot 5| in which is received a sliding block 52, and these blocks are connected by the pivotal stud or shaft 31 which extends through a hub 53 carried on the end of the horizontal arm 54 of an elbow lever 55 which is pivotally mounted on the base portion 43 of the frame as shown at 56. This elbow lever 55 has a vertical arm 51 which is of considerable length and the upper end 58 of which constitutes a handle by which the lever may be manipulated. The swinging of the upper end of the handle to the right or the left Fig. 2 will result in raising -or lowering the pivotal shaft 31 for the rocker, thereby changing the relative lengths of the lever arms of the rocker. Since the eccentric 39 has a fixed throw the shifting of the pivot 31 in the rocker will result in increasing or decreasing the amplitude of the horizontal movement of the dog 2! and thereby the length of the stitch.

The frame 6 is shown as having a quadrant arm 59 secured thereto which is provided with a slot -60 in which operates a clamping stud or screw 6| carried by the arm 51. This clamping stud or screw is provided with a knurled nut 62 by which the arm 51 is clamped to the quadrant arm 59.-

By loosening the nut 62 the operator may manipulate the arm or lever 51 and thereby "change the length of the stitch, and this operation can be carried out while the sewing machine is running and without the necessity of stopping the machine. In carrying out some kinds of sewing operations where relatively long stitches answer the purpose, it is sometimes desirable that the stitches at one or both ends of the seam should be quite close together to form anchoring stitches to prevent the seam from raveling. My improvements are especially adapted for operations of this type because the operator may readily adjust the arm 51 for the formation of short stitches when the machine is set in operation, and after a few stitches have been formed he can then shift the lever 51 to lengthen the stitches to the desired degree without stopping the machine and then the lever 51 can be locked in its adjusted position during the sewing of the seam and until the last few stitches of the seam are to be sewed, at which time the lever 51 may again be shifted to produce the short anchoring stitches at the end of the seam.

While I have illustrated the invention as it might be applied to an overedge sewing machine, yet the invention is not limited in its application to this type of sewing machine, but may be used with other typesof sewing machines.

I claim:

1. A sewing machine comprising a frame, stitch-forming mechanism, a driving shaft therefor, a. feed dog, a carrier for the feed dog, a block connected to the carrier a rocker member having horizontal ways in which said block is received, an eccentric on the driving shaft for oscillating said rocker member and thereby giving said ways a vertical reciprocating movement, a second rocker member, a pivotal mounting therefor between its ends, means connecting the upper end of said rocker to said carrier, a second eccentric on said driving shaft, and means connecting said eccentric to the lower end of the rocker.

2. A sewing machine comprising a frame, stitch-forming mechanism, a driving-shaft therefor, a feed dog, a carrier for the feed dog, a block connected to the carrier, a rocker member having horizontal ways in which said block is received, an eccentric on the driving shaft for oscillating said rocker member and thereby giving said ways a vertical reciprocating movement, a second rocker member, a pivotal mounting-therefor between its ends, means connecting the upper end of said rocker to said carrier, a second eccentric on said driving shaft, a pivoted elbow lever having a horizontal arm carrying said pivotal mounting and also having a vertical arm by which the levermay bemanipulated to shift the pivotal mounting relative to its rocker, a quadrant arm secured to the frame and means for clampingthe vertical arm of said elbow lever to said quadrant.

-3. A sewing machine comprising a frame,-

stitch-forming mechanism, a driving shaft therefor journalled in the frame, a feed dog, a block secured to said feed dog, a rocker memberrhaving horizontal ways in which said block is received, an eccentric on the driving shaft for oscillating the rocker to give said ways a vertical reciprocating motion, a second rocker, a pivotal mounting therefor, means connecting said dog to said second rocker, a second eccentric on the driving shaft, an eccentric strap thereon" having an arm, means pivotally connecting said arm to said second rocker and a guide on the frame for guiding said last-named means in a

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