US1358567A

US1358567A - Throat-plate for sewing-machines

Info

Publication number: US1358567A
Application number: US138223A
Authority: US
Inventors: James R Moffatt; Ralph S Kelso
Original assignee: Union Special Machine Co
Current assignee: Union Special Machine Co
Priority date: 1916-12-21
Filing date: 1916-12-21
Publication date: 1920-11-09
Anticipated expiration: 1937-11-09

Description

J. R. MOFFATT AND R. S. KELSO.

THROAT PLATE FOR SEWING MACHINES.

APPLICATION FILED DEC-21. 1916.

1,358,567. 7 Patented Nov. 9, 1920.

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A Gam a 1. R. MOFFATT AND R. 'S. KELSO. THROAT PLATE FOR SEWING MACHINES.

APPLICATION FILED 050.21, IBIS.

1,358,567. I Patented Nov. 9, 1920.

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WMQ w r UNITED STATES PATENT OFFICE.

JAMES R. MOFFATT AND RALPH S. KELSO, OF CHICAGO, ILLINOIS, ASSIGNORS "I'O UNION SPECIAL DIAGI-IINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 7 OF ILLINOIS.

THROAT-PLATE FOR SEWING-MAOI-IIMS.

Specification of Letters Patent.

Application filed December 21, 1916. Serial No. 138,223.

States, residing respectively, at Chicago, in

the county of 00k, State of Illinois, have invented certain new and useful Improvements in Throat-Plates for Sewing-Ma chines, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

The invention relates to new and useful improvements in throat plates for sewing machines.

An object of the invention is to provide a throat plate which is so constructed as to give the needle thread loop on the looper, as it is moved rearwardly by the feed of the material, a partial twist to cause the looper thread which extends through said loop to be bowed laterally away from the body of the looper, whereby the looper thread loop will be positively spread for the entrance of the needle.

A further object of the invention is to provide a throat plate for sewing machines of the above character, which throat plate is formed with a recess at the side and in front of the needle opening which forms a clearance for that portion of the looper thread extending rearwardly from the forward eye of the looper when said looper is partaking of its forward movement in advance of the needle, thereby avoiding the friction between said thread and the throat plate which would otherwise occur.

These and other objects will in part be obvious and will in part be hereinafter more fully described.

In the drawings which show by way of illustration one embodiment of the invention Figure l is a top plan view of the throat plate embodying our improvements;

Fig. 2 is an enlarged top plan view of a portion of the throat plate;

Fig. 3 is a bottom plan view of that portion of the throat plate shown in Fig. 2;

Fig.4: is a sectional view on the line 4.l of Fig. 2; I

Fig. 5 is a plan view showing in full lines the looper at the forward end ofgthe stroke and in dotted lines the throat plate having our improvements embodied therein;

Fig. 6 is a similar view but showing the looper partly retracted and the looper thread loop deflected away from the looper by the partial twist given to the needle thread loop through the action of our improved throat plate thereon;

Fig. 7 is a similar View, but showing the looper having been retracted to a further extent;

Fig. 8 is a similar view, but showing the looper at the rear end of its stroke;

Fig, 9 is a sectional view through the throat plate, showing the needle and the looper, with the looper at the rear end of its stroke;

Fig. 10 is a similar view, but showing the looper as positioned in Fig. 7; and

Fig. 11 is a sectional view through the with the line of feed and enters the needle thread loop in a direction opposed to the feed, it is difficult to spread the looper thread loop from the body of the looper so as to separate the strands of the looper thread loop for the entrance of the needle. The present invention is directed to a throat plate which is constructed so that said throat plate, operating upon the needle thread loop on the looper, will give said needle thread loop a partial twist in such a direction as to cause said needle loop to deflect the looper thread extending from the eye of the looper back throughsaid needle loop to the previous concatenation of the threads away from the body of the looper. Our improved throat plate is also provided with a recess located relative to the needle opening, so as to form a clearance space to permit the free spreading of the looperthread loop, and also to prevent the looper thread from reeving across the metal parts of the throat plate.

Referring to the drawings in detail, our improved throat plate is indicated at 1. Said throat plate is formed with feed slots therein, which are formed so as to receive the feed dogs which move the material. In Fig. 1 of the drawings we have shown a throat plate which is intended to be used Patented Nov. 9, 1920.

in connection with a single needle machine,

and, therefore, only one needle opening and the construction of the throat plate adjacentthe same will be described.

Extending rearwardly from the needle 7 opening 3 and ina direction parallel with of the needle opening.

the line of feed, is a slot 5. The direction of the line of feed is indicated by the opening in the throat plate for the feed dog. The feed dog movesback and forth in a direction longitudinally of the openings therefor. This slot 5 is inclined to theplane .ofwthe work support, as clearly shown in Fig. 4. It is also disposed elative to the needle opening, so as to form a shoulder 6 at the under face of the throat plate, which shoulder extends to one side of thecenter of the needle opening. In other words, the wall 6" of the slot 5 extends from a point 7, which is at the right hand side of'the. needle opening as viewed in the direction of feed, to a point 8 which is at the left hand side This slot 5 extends a distance back from the needle opening greater than a stitch length, and the shank of the needle thread loopmoves back into the slot when the material is fed.

The operation of this slot in the throat plate on the needle thread loop will be made clear from Figs. 5 to 8 of the drawings, wherein the looper is indicated at 9, and the looper thread is indicated at 10. The needle thread is indicated at 11, while the needle is indicated at 12 in Figs. 9, 10 and 11 of the drawings.

The needle when it reaches the lower end of its stroke and begins its upward movement, throws out a loop of thread in the well known manner, and the looper enters the thread loop. In Fig. 5 of the'd'rawings the looper is indicated at the forward end of its stroke. Tt is still in theneedle thread loop which is indicated at 11. When the looper moves into the thread loop, it'moves in a direction opposed tothe direction'of feed which is indicated by the arrow in Fig. 5 of the drawings. As the material is fed rearwardly by the feed, it will be noted that the last concatenation of the threads is really moved'backwardly in the direction of the longitudinal axis of the looper and would tend to cause the looperthread to lie close to, the body of the looper.

In other words, when the looper moves across the line of the feed, as occurs in certain types of machines,the feed of the material, which is at ight angles to the longitudinal axis of the looper body, separates the looper thread from the body of the looper. In the present case the feed of itself,however, as abovenoted, is of no as sistance in separating the looper thread from the bodyof the looper when the looper moves in a direction parallel with the'line of feed. This backward movement of the needle thread loop through the feeding of the material carries the shank of the looper .thread loop into the slot 5. The shoulder (3 is engaged by the right hand strand ofthe needle thread loop, which carriesthe left hand strand first into the slot, as clearly shown in Fig. 2 of the drawings, and this gives a partial twist to the shankof the needle thread loop which is on the looper.

At this time the looper'thread extends from the eye of thelooper-througlrthe needle thread loop onthe looper to the previous concatenation of the'threads. The partial twist given to the needle thread loop on the looper, will cause the looper thread during the backwardmovement of the looper to be bowed outwardly away from the body of the looper, or separated therefrom, as clearly shownin Fig. 6, and thus the looper thread loop is spread so as to permit the, needle to enter between the looper thread and the body of the looper.

As above noted, the shoulder 6 isat one side of the needle opening, and as a result the edge of the wall of the slot 5 directly in rear of this shoulder is engaged by. the needle thread loop on the looper and the lateral movement of the looper draws the needle loop tightagainst this edge. This puts the needle thread loop under greater tension and insures the positive bowing of the looper thread in the proper direction. it will be further noted that the looper thread extending from the eye of the looper back through the needle thread loop will, at

thread loop, be carried laterally through this lateral shifting of the needle thread loop,'and this occurs at the time when the half twisting of'the needle thread loop bows the looper thread orseparates it from the body of the looper. V

The throat plate on the under face there-- of is provided with a recess which extends along the side of the needle opening, as inthe point where it passes through the needle dicated at 13 and in front of the needle This recess is constructed and disposed so as to provide a clearance space to permit the free spreading of the looper thread loop and also" to prevent the looper thread from rubbing against the edge of the needle opening, that is, the metal parts of the throat plate, during the forward movement of the looper. There is openin as indicated at 1%.

also a projecting pin on the under faoe of the throat plate which is located directly in front of the needle opening. This pin plays no part in the positive spreading of the looper thread loop. It does,however, serve as a guard or check to prevent the'loop from closing or the looper thread shifting across the path of the needle until the point of the needle has passed the looper thread.

It is obvious that minor changes in the details of construction may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus fully described our invention what we claim as new and desire to secure by Letters Patent is 1. A throat plate for sewing machines having a needle opening and a slot leading into said needle opening and extending rearwardly therefrom, said slot at the lower face of the throat plate being disposed at one side of a line extending directly rearwardly from the center of the needle opening so that the shoulder formed between the slot and the needle opening will engage the needle thread loop on the looper and cause 7 the strands of said needle thread loop to move one after the other into the slot, thus giving a partial twist to the needle thread loop on the loopervfor causing the needle thread loop to deflect the looper thread away from the body of the looper.

f2. throat plate for sewing machines having a needle opening, a slot extending rearwardly from said needle opening and said slot being inclined to the plane of the throat plate and disposed so that the shoulder formed between the slot and the needle opening at the lower face of the throat plate will engage the strands of the needle thread loop on the looper and cause said strands to move one after the other into the Slot, thus giving a partial twist to the needle thread loop on the looper for causing said needle thread loop to deflect the looper thread away from the body of the looper.

3. A throat plate for sewing machines having a needle opening and a slot eXtending rearwardly from said needle opening, said slot being inclined to the plane of the work support and disposed relative to the needle opening so as to give a partial twist to the needle thread loop on the looper as said needle thread loop is moved into the slot by the feed of the material for deflecting the looper thread away from the body ofthe looper, said throat plate having a projecting pin in front of the needle opening adapted to retain the looper thread loop spread after said looper thread loop has'been moved away from the body of the looper.

4;. A throat plate for sewing machines having a needle opening and a slot extending rearwardly from the needle opening, said slot being inclined to the plane of the throat plate, said throat plate having a re cess at the side of the needle opening in the under face thereof and also in advance of the needle opening to form a clearance space for the looper thread.

In testimony whereof, we aflix our signatures in the presence of two witnesses.

JAMES R. MOFFATT. RALPH S. KELSO.

Witnesses;

S. Gnonen TATE, F. C. BUTLER.