US2180073A - Tufting mechanism for sewing machines - Google Patents

Description

Nov. 14, 1939. 1.. A. SMITH WING MECHANISM FOR SEWING MACHINES I Filed Aug. 2, 1938 2 Shee ts-Sheet l Nov. 14, 1939. 1.. A. SMITH 8 5 I rurrme MECHANISM FOR SE-WING MACHINES Filed Aug. 2, 1938 2'Sheets-Sheet 2 .Pate ted Nov. 14, 1939 I um 'ao STATE S PATENT QFFICE LTUFTING mzcnnmsu Fon sawmo Loyd A, Smith, Lexington, N. 0.,

Point Manufacturing Company aslignor to Wc'st West Point,

Ga.,, a corporation of Alabama Applicationxugust 2, 1938, Serial No. 222,711

11 Claims. (CL 112-79) 4 j extension or 'ipstanding port tiallyits lowermost position.

Figure 2 is a view similar to Figure 1 except that the feedbar is omitted, and that the elements of the tufting mechanism are in the position they occupy when the loopfor tuftingis completely formed.

Figure 3 is a view similar to Figure 2 but showing the position of the elements at substantially the moment that the loop is cut.

Figure 4 is a top view showing the mechanism .applied and with the machine table and feed bar omitted, and

v Figure 5 is a vertical longitudinal sectional view onthe line 5-5 of Figure 4. In the drawings, the numeral l designates the base plate or a table of a sewing machine of usual construction and provided with a throat" plate I I, needle bar l2, feed bar I3 and rock shaft l4. The table II! is provided with the usual depending lugs l on each side of the throat plate aperture and ordinarily used to support the bobbin retainer. The rockshaft l4 has the usual disk 15 fixed to its lower end, this disk including an eccentrically mounted pin. l1.

The mechanism of the present invention comprises a plate-like supporting element or base plate 20 which has, vertically extending slots 2| therein. A machine screw 22 extends through each of .the slots 2| and into the depending lugs i5 of the machine base plate I0 so that the supporting element 20 and the parts carried thereby can be secured in fixed relation to the sewing,

machine. The provision-of the slots 2| enables the tufting mechanism to be positioned at various distances below the throat plate H', thus regulating the length of the tufts formed upon the sewing machine. The supporting element or base plate. 20 is cut away at its-upper central portion to form a recess 24 of generally arcuate form.

" The left hand upper edge of the base plate 20,

as viewed in Figures 1 to 4, includes a vertical gpie tufting mechanism of the invention in posiition, and with the machine needle in substan-,

on is, this upstanding portion having a horizontal groove "across its outer,

secured to a looper carrier or arm 31, which car- 5 v face; as best shown in Figures} and 5, to receive afixed gripping element and looper guide 21,;the latter element being fixed to the 5 base plate fli-aby means of a machine screw 28 extendingthrough a horizontal slot 29 andinto the basewplate'. The provision of the horizontal slot 29 enables the position of the gripping and guide element 21 to be adjusted. A fixed cutting blade or -edgeill is provided at the right hand or innermost end of the element 21; theblade edge being'slightly inclined as shown in- Figures 1 to 3 and extending from the upper edge of the element?! to a point midway of its depth. A looper guide arm 3| extends from the element}? below the cutting blade 30,--the guide portion if being slightly recessed as indicated at 34 in Figures 4 and 5 from its upper edge to a point adjacent its lower edge and on its side surface which faces thebase plate 20.

A looper 36 of generally arcuate form is positioned to move within the recess 24 of baseplate 20, looper 36 having its trailing and larger end rier is pivotally supported in the base plate 20 by means of a shouldered machine screw 3! threaded in the looper carrier 31 and journalled in the base plate. The upper end of the looper carrier 3'! is forkedas indicated at 39 to receive the pin I! carried by the rock shaft l4. By'this arrangement, the looper carrier and the looper will be swung or oscillated from the position shown in Figure l to the position shown in Figure 3, and return, by the motion of the rock shaft l4.

The looper 35 is of pointed form at its leading- .end .42, and is of gradually increasingcross-section, at least in a vertical plane, toward its trailin'g portion. A horizontally and outwardly pro- 40 jecting shoulder or arm 43 is provided on the upper surface of the looper 36 at the trailing portion thereof, this shoulder being so positioned that during the final tufting action of the looper, .itwvill serve as one portion of a thread gripping device. It will be noted from Figure '4 that the shoulder 43 projects over the base plate 20. The lower tr-ailing portion of the looper 36 is ground to a cutting blade as indicated at 44 and is adapted to coact with the fixed cutting blade 30 in an overlapping or scissors relation when the .two are positioned adjacent each other as shown in Figure 3.

The other element of the gripping device is provided by a vertically extending arm 45 swing- 5 the looper st will bring the gripping shoulder 4s the same time, the cutting blade 44 of the looper carried by the looper into engagement with the shoulder 41 so that the thread will be gripped between these two elements for subsequent cut-.

ting by the cutting device of the mechanism. The arm 0 which carries the gripping shoulder 41 is normally held in the position shown in.

Figure 1 by means of a coil spring 40 which extends from the lower end of the arm 40 to a suitable stud II at one end of a stop plate ll adJustably secured to the base plate 20 by a set screw II. The inner end ll of the stop plate 8| abuts against the lower portion-of gripper arm N to serve as a stop, the position of the stop plate being adjustable due to the fact that the set screw It extends through a h'orizontal slot in the stop plate as shown in Figure 2.

In'the operation of the tufting mechanism of the present invention, with the mechanism fixed beneath the throat plate of the sewing machine, for example, in the manner illustrated in the drawings, and with a piece of material upon the table Iii of the machine, when the needle bar I! carries the needle I! downwardly to its extreme, lowest position illustrated in Figure 1, the looper 3! will swing to ,the left on the pivot 38. Such movement of the looper will spread the run of thread T which extends back from the previous tuft in the material to the eye of the needle, thereby forming a loop as diagrammatically indicated in Figureh The thread to form this loop will be drawn from the stretch of thread T, which extends between the needle eye and up' the opposite side of the needle and then through an aperture, not shown, in the extreme upper end of the needle bar. The looper will of course move inwardly to form the loop while the needle is still lowered, the needle being recessed as shown at I!" in Figure 5 on its side facing the looper and to permit such movement of the looper. The recess l2 also insures that the looper point will be able to get between the needle and the stretch of thread T.

When the looper 36 has reached the position illustrated in Figure 2; the needle point will be just above the shoulders 43 and 41. Thegripping shoulder 43 on the looper may therefore come into contact with the gripping shoulder 11 of the gripping bar 46, so that the upper portion of the loop of thread now formed about looper 38 will be gripped between these two elements as indicated in Figure 2.

Continued swinging movement of the looper carrier 31 to the left by the rotation of rock shaft is will cause the gripping element II to be moved from its nonnal position shown in Figure 2 to the position illustrated in Figure 3, by reason of the fact that the gripping shoulder 43 of-the looper will be pressing against the grip ping shoulder 41 of the gripping element 48. At

will move past the fixed cutting blade 30. with the result that the loop of thread will be sheared and the bight T of thread will form one leg of a U-shaped tuft, as is common practice.

During the operation described in the preceding paragraph, the needle bar i2 will be moving upwardly, and such upward movement will cause vgripping device, that is, from the position almost directly below the needle I! as shown in Figure 2 to the position shown in Figure 3. At the same time, 'as is usual in sewing machines at the moment Just prior to descent of the. needle, the

feed bar It will be moving the fabric to the left. In other words, the thread will be moving to the left with the fabric at the moment that the thread is cut. This eliminates all possibility of the tuft being pulled partly through the fabric,

as can occur with tufting mechanisms in which the thread is slipped and firmly held at the moment that the fabric is being moved over the table of the sewing machine by the feed bar.

After the threadthe' thread has been cut in the manner described above, the looper it will be swung backwardly to the position shown in Figure 1. When the looper has reached the position shown in Figure 2, the gripping element 46 will have been restored to normal position by the spring 49.

I claimz- 1. In a tufting mechanism, a supporting element, a looper oscillatable with respect to said element, a gripping element facing said looper, gripping means on said looper arranged to cooperate with said first-named gripping element,

and opposed cutting edges on said supporting element and said looper, respectively.

2. In a tufting mechanism, a supporting ele-' ment, a looper oscillatable with respect to said element, a gripping element normally urged towards said looper, gripping means on said looper arranged'to cooperate with said first-named gripping element, and opposed cutting edges on said supporting element and said looper, respecvely.

3. In a tufting mechanism, a supporting element, a looper oscillatable with respect to said supporting element, a gripping element pivoted on said element, spring means to normally urge said gripping element toward said looper, gripping means on said looper to cooperate with said first-named gripping element, and opposed cutting edges on said supporting element and said looper, respectively.

4. In a tufting mechanism, a supporting element, a looper movable with respect to said supporting element and including gripping means and a cutting edge, a second cutting edge carried by said element, and gripping means supported by said element and adapted to cooperate with said first-named gripping means, said last named gripping means being movable with respect to said element, and means to hold said gripping means in engagement with the thread to be cut during movement with respect to the supporting element.

'5. In a tufting mechanism, a supporting ele- 6. In a tuiting mechanism, a supporting element, 9. looper movable with respect to said supporting element and including gripping means and a cutting edge, a second cutting edge adjustably carried by said element, and gripping means supporting by said element and adapted to cooperate with said flrst-named gripping means, said last named gripping means being movable with respect to said element, and adiustably tensioned spring means to hold said gripping means in engagement with the thread to be cut during movement with respect to the supporting element.

7. In a tufting mechanism, a supporting plate, an arcuate looper movable with respect to said supporting plateand adapted to be oscillated by a sewing machine rock shaft, said looper having a gripping shoulder on its upper surface and a cutting edge below said gripping shoulder, a cutting edge on said supporting plate adapted to cooperate with said first named cutting edge, and a gripping element on said supporting plate and adapted to cooperate with the gripping shoulder on said looper.

8. In a tufting mechanism, a supporting plate, an arcuate looper movable with respect to said supporting plate and adapted to be oscillated by a sewing machine rock shaft, said looper having a gripping shoulder on its upper surface and a cutting edge below said gripping shoulder, a cutting edge on said supporting plate adapted to cooperate with said first named cutting edge, a gripping element pivotally mounted on said supporting plate, and resilient means to normally hold said last named gripping element toward the gripping shoulder on said looper.

9. The combination in a sewing machine of a needle, presser foot, feed bar, and rock shaft, a supporting plate, a looper operatively connected to the rock shaft and movable with respect to said supporting plate, said looper having a gripping shoulder and a cutting edge thereon, a second cutting edge rigid with said supporting plate, a gripping element carried by said supporting plate, means to hold said last named gripping element toward said gripping shoulder, said needle having a cutout adjacent its end to permit it to move, between said looper and said fixed cutting edge, said supporting plate having a recess therein to receive the needle.

10. The combination in a sewing machine including a needle and a feed bar, of a looper, means to grip a loop formed upon said looper, means to move said gripping means and loop with the feed bar during the fabric-feeding motion of the latter, and means including a stationary element to cut the loop during such movement.

11. In a tufting mechanism, a supporting element, a looper movable in opposite directions with respect to said supporting element and needle, a gripping element facing said looper, gripping means on said looper arranged to cooperate with said first named gripping element, and op- 30 posed cutting edges on said supporting element and said looper, respectively.

LOYD A. SMITH.

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