US2588274A - Sewing machine - Google Patents

Description

March 4, l52

Filed Feb. 10, 1949 C. W. MUELLER SEWING MACHINE 3 Sheets-Sheet l INVENTOR CHARLES w. MUELLER BY :6? y-M ATTORNEY March 4, 1952 w, MUELLER 2,588,274

SEWING MACHINE Filed Feb. 10, 1949 3 Sheets-Sheet 2 INVENTOR CHARLES W. MUELLER ATTORN EY March 4, 1952 c. w. MUELLER 2,588,274

SEWING MACHINE Filed Feb. 10, 1949 3 Sheets-Sheet 3 INVENTOR CHARLES W. MUELLER age/7M ATTORNEY Patented Mar. 4, 1952 SEWING MACHINE Charles W. Mueller, St. Louis, M0,, assignor to Lewis Invisible Stitch Machine Company, a

corporation of Maine Application February 10, 1949, Serial No. 75,619

Claims.

The invention herein disclosed relates to a sewing machine of the kind in which'a looper receives a loop of thread formed on the return stroke of the needle, twists the loop and presents the loop for passage therethrough by the needle on the next or penetrating stroke of the needle. More particularly, the invention relates to a mechanism for driving or actuating the looper.

As constructed heretofore and prior to this invention, the drive mechanism for the looper, particularly in blind-stitch, chain stitch sewing machines has been in a large measure, a limiting factor on the speed at which the machine can be operated. A relatively complicated so-called knuckle or looper joint has been used, and due to its construction there is no way of providing a continuous supply of oil to the relatively movable parts thereof in bearing or surface contact.

An object of this invention is to provide, in a machine of the kind mentioned, a comparatively simple drive mechanism for a looper. Another object of the invention is to provide a looper joint to which oil may be continuously supplied. A further object of the invention is to provide a looper joint that may be operated at comparatively high speed.

The foregoing objects and certain advantages that will hereinafter appear are realized in the embodiment of the invention illustrated in the accompanying drawings and described in detail below, from which description a clear understanding of the invention may be had.

The drawings include:

Fig. 1 which is a front elevation of a machine embodying the invention;

Fig. 2 which is a fragmentary, end elevation of the same showing the looper drive mechanism, taken on the line 2--2 of Fig. 1;

Fig. 3 which is a fragmentary transverse section taken on the line 33 of Fig. 2;

Fig. 4 which is a fragmentary, sectional elevation of the same taken on the line 4- of Fig. 2 and showing the crank rotated through one hundred and eighty degrees;

Fig. 5 which is a fragmentary end elevation similar to Fig. 2 with the crank rotated clockwise through ninety degrees,

Fig. 6 which is a similar view with the crank rotated one hundred and eighty degrees from the position shown in Fig. 2;

Fig. '7 which is a like view with the crank rotated two hundred and seventy degrees from the position shown in Fig. 2;

Fig. 8 which is a fragmentary, sectional view taken on the line 8-8 of Fig. 2;

Fig. 9 which is a transverse section taken on the line .9-9 of Fig. 4;

Fig. 10 which is a side elevation of a bushing showing the oil groove therein;

Fig. 11 which is a view similar to Fig. 4 showing a modified arrangement of an oil cup; and

Fig. 12 which is a sectional elevation of the oil cup of Fig. 11, taken on the line l2|2 of Fig. 10..

The particular sewing machine illustrated in the drawing, for the purpose of disclosing the invention and in which the looper drive mechanism of the invention is especially desirable, is a blindstitch, chain-stitch sewing machine. This machine includes a frame upon and within which all of the mechanism is mounted. The frame comprises a base I, a post or standard 2 secured to the base at the rear thereof, an arm 31 extending laterally from the upper end of the post, aforwardly extending arm 4, secured to the end of the arm 3, and a work table 5 secured to the base at the front end thereof and extending to the forwardly extending arm 4. The several sections of the frame are hollow, and within and on the sections, operating and driving mechanism are mounted.

The sewing machine is actuated through a main shaft 6 that is journaled in the post 2 and the arm 3. This shaft extends through the post and has fixedly mounted thereon a combined pulley I and hand wheel 8. The pulley is driven by a belt 9 from a power shaft or an electric motor, not shown.

On the end of the arm 4, there is a presser foot [0 that overhangs the end of the work table 5. The work, the cloth being sewn, is supported against this presser foot. The presser foot is of the usual and well-known construction and has an opening therethrough, through which, during the operation of the machine, successive nodes of the material bein sewn are projected.

The stitch-forming mechanism is of the usual and well known kind in sewing machines of this type. A needle bar shaft I2 is journaled in the arm 4 and extends through the forward end thereof, the end near the operator. On the extended end of the arm I2, there is secured a needle bar l3 which carries a curved needle l4. Through suitable connections with the main shaft 6, the needle the needle and the cloth as the needle returns. The looper moves into this loop, engages the loop, withdraws, turns to twist the loop, and returns to position the loop so that on the next succeeding penetrating stroke of the needle, the needle passes through the loop after passing through the cloth. The looper then sheds that loop and returns to pick up the next loop thrown on the return stroke of the needle.

The invention herein disclosed provides a novel and improved mechanism for actuating the looper. One specific embodimentof the looper driving or actuating mechanism is illustrated in Figs. 2 to 11 of the drawings, This particular mechanism is actuated by the main shaft 6 of the sewing machine.

The end of the main shaft 6 is provided with a reduced end portion 6a. On this reduced end portion 6a, there is mounted a crank 16. The crank I6 is a counter-weighted or balanced crank, and it is provided with a crank arm I! that is inclined to a plane radial to the axis of the shaft 6. The crank arm ll is provided with an opening I8 therethrough. Abushing I9 (Figs. 4 and 10) has a reduced end portion 20 which extends through and makes a forced fit in the opening of the crank-arm ll. The enlarged end 2| of the bushing extends beyond the crank-arm. The bushing l9 forms a bearing for a crank-stud 22 that extends therethrough and is journaled therein.

The crank-stud 22 is provided with a head 23 that engages the extended, free end of the portion 29 of the bushing l9. This crank-stud extends well beyond the bushing it. It is hollow and has an elongated slot 2?; formed through one surface adjacent the free end thereof, and two oil holes 26 and 21 drilled through the wall intermediate the ends thereof. It is held in the bearing bushing 19, against longitudinal movement with respect thereto, by a block-J8 that is clamped thereon and extends laterally therefrom. The block 28 abuts against the end of the larger section 2| of the bushing H).

The block 28 carries a pivot pin 29 which extends through an opening therethrough and is fixedly secured therein by a set screw 39. The pivot pin opening through the block, and the pivot pin 29 are spaced from and extend at right angles to the axis of the crank-stud 22. A fiat surface 3! is provided on one side of the pivot pin, against which the end of the set screw 39 abuts to secure the pivot pin in a fixed position with respect to the block 23. Diametrically opposite the slot 3|, there is provided, in the pivot pin 29, an oil groove 32 which extends longitudinally of the pivot pin. l.

The pivot pin 29, that is the extended ends of the pivot pin 29, receives and constitutes a pivot for the bifurcated end 33 of a yoke 34. The bifurcated end 33 of the yoke 34 embraces the block 28, and the arms thereof are provided with bearings 35 and 36 which are journaled on the extended ends of the pivot pin 29. The yoke 34 has an internally threaded, split end 37 which receives a complementary threaded end of a looper carrier or looper bar 33.

The looper bar 38, adjacent the free end thereof, has secured thereon a partial, spherical fixture or member 39. This partial, spherical sector 39 is received in a complementary opening in an arm 40. The arm 49 is fixed to a stud 4! by a clamping screw 42. The stud 4! is journaled in an eccentric 42, which in turn is journaled in a bracket 43 extending from and integral with the arm 4. The eccentric 42 is provided with a knurled finger wheel 4 by means of which it may be manually rotated in the. bracket 43 so as to adjust the position of the looper H5. The looper bar or carrier 38 is provided, at its free end, the end extending through the arm 49, with an offset portion 45. To this offset portion 45 of the looper carrier, the looper i5 is secured.

The looper joint, consisting of the crank-stud 22, bushing l9, crank block 28, pivot pin 29 and the arms 35 and 36 of the yoke 33 are lubricated by a sight oil cup 45. In the embodiment of the invention shown in Figs. 2 to 10, the oil cup 46 is mounted on the rear wall 4'! of the arm 4. An oil delivery tube 48 connecting with the bottom of the oil cup 46 extends through the wall, the rear wall 41 of the arm 4, to a point over the slot 25 in the crank-stud 22. "With this arrangement, as is well known in the art, a drop of oil is released from the end of the tube 43 at definite, timed intervals. In the construction illustrated, a drop of oil released from the tube 45 will fall into the slot 25 in the crank-stud 22. Notwithstanding the rotation of the crank with the shaft 6, the slot 25 in the crank-stud 22 will always remain beneath the end of the fixed oil tube 48.

As seen in Figs. 2, 4 and 5 to '7, regardless of the position of the shaft 6 or crank arm H, the slot 25 of the crank-stud 22 remains under the end of the oil tube 48 leading from the oil cup 16. The crank-stud 22 does not rotate about its axis. In view of its inclination (Fig. 4), it forms with the prolongation of the axis of the shaft 6, a triangle which on rotation of the shaft 6 generates a cone' The slot 25 of the crank stud 22, at the intersection of the prolongation of the axis of the .shaft 6, never changes its position with respect to the end of the oil line or tube 48. Thus, regardless of the position of the shaft 6 or the crank arm [1, the slot 25 of the crank-stud 22 is always in position to receive oil dropping from the end of the stationary oil line 48. The free end of the crank-stud 22 is closed by an internally, force-fit cap 49 so that no oil can flow from the free end of the crank-stud. Regardless of the position in which the crank-stud receives oil through the slot 25 therein, it retains that oil, and in its elevated or upwardly inclined position, such as illustrated in Figs. 2 and '7, the oil received through the slot 25 flows to the oil openings 26 and 21.

The bushing 19 and the block 28 are provided with oil holes and oil grooves to distribute the oil received in the crank-stud 22 to the bearing.

surface of the bushing l9, and the oil groove 32 in the pivot pin 29.

For this purpose, the oil hole 26 through the wall of the crank-stud 22 is located at the free edge of the portion 2! of the bushing 19. The internal surface of the bushing I9 is provided with an oil groove 50 of the kind that is commonly termed in the art, a Fig. 0 oil groove. The oil groove 50, in the bushing 19, is open through the end of the section 2|. Thus, oil passing through the oil hole 26 in the wall of the crankstud 22 can enter the oil groove 59 to provide oil between the internal surface of the bushing l9 and the crank-stud 22 and also between the end surface of the bushing 19 and the block 28.

The oil hole 21 (Figs. 8 and 9) through the wall of the crank-stud 22 is aligned with an oil hole 5| in the block 28 which extends from the opening therethrough, through which the crank-stud 22 extends, to the opening through which the pivot pin 29 extends. The opening 5| is aligned with the oil groove 32 in the pivot 29. Thus, through these openings and the groove 32 both bearings 35 and 36 of the yoke 34 are lubricated by oil dropped into the slot 25 of the crankstud '22.

A modified arrangement for applying oil to the slot 25 in the crank-stud 22 is illustrated in Figs. 11 and 12 of the drawings. In this arrangement, an oil cup 52 is mounted below the arm 4 and directly above the slot 25 in the crank-stud 22. An oil tube 53 extending vertically from the oil cup 52 is directly over the slot 25 in the crankstud 22 at the position where the slot 25 intersects a prolongation of the axis of the shaft 5. The upper end 54 of the oil cup projects slightly through the frame of the arm 4 so that it is readily available for filling the cup with oil. The oil cup 52 is provided with a manually adjustable arrangement for regulating the amount of oil supplied to the crank-stud 22. For this purpose, the bottom 55 of the oil cup is provided with a conicar seat 56 through the apex of which an oil supply hole 5! extends. The fiow of oil through the oil hole 51 is regulated by a ball 58 which is positioned to engage the conical seat 56. The ball 58 is supported on a block 59, within a depending skirt 50 on the bottom of the oil cup, which block is in turn supported on the end of the hollow rod or tube 53. This hollow rod or tube has a conical end 6| engaging a complementary seat in the block 59 and openings 62 through the side wall thereof. The tube 53 has a portion 63 with an external thread thereon in threaded engagement with an internal thread on the skirt 60. 'Thus, by rotating the tube 53, the ball 58 may be moved toward or away from the seat 56, and the flow of oil through the tube may be regulated. For rotating the tube 53, there is provided a finger lever 64 which extends outwardly beyond the edge of the arm 4.

From the foregoing description of the embodiment of the invention illustrated in the drawing and described in detail above, it will be seen by those skilled in the art that by this invention there is provided a drive mechanism for actuating a looper that may be run at very high speed, that is simple in construction, and that is so constructed that oil may be continuously supplied to all parts in bearing contact.

It will be obvious that various changes may be made by those skilled in the art in the details of the embodiment of the invention illustrated in the drawing and described above within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. In a sewing machine of the kind described having a looper-carrier, drive mechanism for the looper-carrier comprising in combination a 1'0- tatably mounted drive shaft, means for rotating the shaft, a crank secured on the end of the shaft, a crank-stud rotatably mounted in the crank, extending therefrom and inclined to the axis of the drive shaft, a. member secured to said crank stud and extending laterally therefrom, and means pivotally connecting said looper-carrier to said member on a pivot having an axis spaced from and at right angles to the axis of said crank stud.

2. In a sewing machine of the kind described having a looper-carrier, drive mechanism for the looper-carrier comprising in combination a rotatably mounted drive shaft, means for rotating the shaft, a crank secured on the end of the shaft, a crank-stud rotatably mounted in the crank, extending therefrom and inclined to the axis of the drive shaft, a member secured to said crank stud and extending laterally therefrom, and means pivotally connecting said looper-carrier to said member on a pivot having an axis spaced from and at right angles to the axis of said crank stud, the several parts having oil passages for supplying oil to the surfaces thereof in rubbing contact.

3. In a sewing machine of the kind described having a looper-carrier, drive mechanism for the looper-carrier comprising in combination a rotatably mounted drive shaft, means for rotating the shaft, a crank secured on the end of the shaft, a crank stud rotatably mounted in the crank, extending therefrom and inclined to the axis of the shaft, a block secured to the crank stud and extending laterally therefrom, a pivot pin carried by the block, spaced from the crank stud and extending at right angles to the crank stud, and a member connected to said loopercarrier and pivotally mounted on said pivot pin.

4. In a sewing machine of the kind described having a looper-carrier, drive mechanism for the looper-carrier comprising in combination a rotatably mounted drive shaft, means for rotating the shaft, a crank secured on the end of the shaft, a hollow crank stud rotatably mounted in the crank extending therefrom and inclined to the shaft, the crank stud including a portion having a slot therein extending across the prolongation of the axis of the shaft, a block secured to the crank stud intermediate the ends thereof and extending laterally of the axis thereof, a pivot pin secured in the block, spaced from the axis of said crank stud and extending at right angles thereto, a yoke embracing the block and pivoted on said pivot pin and connected to said loopercarrier, the said crank stud, block and pivot pin having oil passages therethrough, and an oil feed mounted above the slot in the crank stud and positioned to drop oil into the slot.

5. In a sewing machine of the kind described having a looper-carrier, drive mechanism for the looper-carrier comprising in combination a rotatably mounted drive shaft, means for r0- tating the shaft, a crank secured on the end of the shaft, a hollow crank stud rotatably mounted in the crank, extending therefrom and inclined to the axis of the shaft, the crank stud including a portion intersecting the prolongation of the axis of the shaft and having a slot through the wall thereof and oil passages through the wall between said slot and the crank, a block secured to the crank stud intermediate the ends thereof and having a pivot pin opening therethrough spaced from the crank stud and extending at right angles thereto and an oil passage connecting one of the oil passages through the wall of the stud and the pivot pin opening, a pivot pin fixed in the opening in the block and having an oil groove in the surface thereof communicating with the oil passage in the block, a yoke pivoted on said pivot pin and connected to said looper-carrier and means for delivering oil to the slot in the crank stud.

CHARLES W. MUELLER.

Name Date Kelso Apr. 2, 1940 Number

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