US2023316A - Sack sewing machine - Google Patents

Description

Dec. 3, 1935. EBERT 2,023,316

SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 1 Dec. 3, 1935. F. EBERT SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 2 w w n 5 HQ 3, 1935. F. EBERT SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 3 Dec. 3, 1935. F. EBERT 2,023,316

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Dec. 3, 1935. EBERT 2,023,316

SACK SEWING MACHINE Filed July 5, 1950 9 Sheets-Sheet 5 a? a5 a: 15

Dec. 3, 1935. EBERT 2,023,316

SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 6 Dec. 3, 1935. F. EBERT 2,023,315

SACK SEWING MACHINE Filed July 3, 1930 9 Sheets-Sheet 7 Dec. 3, 1935. EBERT SACK SEWING MACHI 9 Sheets-Sheet 8 Filed July 3, 1930 Dec. 3, 1935. F. EBERT SACK SEWING MACHINE Filed July 5, 1930 9 Sheets-Sheet 9 Ll/Zn fdr:

l nk; fjerf Patented Dec. 3, 1935 UNITED STATES PATENT OFFICE Application July 3, 1 In Germany 930, Serial No. 465,729

July 13, 1929 16 Claims. (Cl. 112-162) The present invention relates to a sack sewing machine, and particularly to large and heavy types embodying novel features to permit operation at a much higher speed than is possible now. This effect is produced, above all, by a new and. extraordinarily stable drive of the loopers, which eliminates the usual transmission by means of rods lacking in stableness and vibrating at high speed operation or of toothed segments.

According to the invention, the drive of the thread-carrying lower thread looper constitutes a self-contained unit which can be manufactured separately and attached to the machine as a whole. Moreover, the device can be turned about a vertical axis and adjusted so that the lower thread is brought safely in front of the needle and a rapid change from narrow to broad seams or vice versa can be effected.

The drive of the lower thread looper contains an articulated connection by means of which the looper is held to its front end position until the needle ascends again and the needle loop has opened, which insures the proper formation of stitches. The length of time during which the looper is kept idle can be regulated by adjusting the driving lever. The looper lever itself permits of axial and torsional displacement, it being fixably positioned on the boss of a driven intermediate lever. This adjustability is of particular importance when needles of different sizes and thicknesses are employed.

Furthermore, the lower thread is regulated by the vertically oscillating looper lever, whereby a much finer adjustment is attained than by employing rotary regulators of the usual type. For this purpose, a projecting arm of the looper lever, which cooperates in the latters pendulumlike motion, is provided with a thread-receiving eye cooperating with two stationary eyes which can be adjusted independently of the oscillating eye.

The lower thread looper is provided on its back with a rib over which passes the needle thread loop on the looper while the other looper thread is positioned in the groove-like indentation above the rib, the two threads being thus prevented from coming into contact with one another or the friction being at least reduced to a considerable extent so that breakage of thread due to friction is eliminated and a poorer quality of thread can be worked.

The ordinary looper moving over the table of the machine is of very rigid construction also. It is driven directly from the main shaft of the machine and from the end where the stitch-forming devices are located. A crank serves as a driving means which is arranged on the shaft and actuates directly, by means of a-ball-joint and a lever, the looper lever disposed axially and torsionally displaceable on the boss of this lever. This construction eliminates not only the usual less stable connecting rods, but reduces also the number of turning points to a minimum, which contributes to a considerable increase in speed.

The auxiliary looper required for sewing with two threads and adapted to hold the looper thread until the pull of the needle loop has taken place is driven directly from the lever of the looper moving over the table, the arrangement being such as to make the entire driving mechanism of the main loopers readily accessible.

Provision has finally been made to sew with two or three threads on the same machine. For this purpose the auxiliary looper with drive can be removed and replaced by a fixed thread guide cooperating with a thread eye arranged on the oscillating lever of the looper moving over the table, whereby the second lower thread is regulated by the motion of its own looper.

One embodiment of the invention is illustrated in the accompanying drawings, in which Figure 1 is a front view of the sewing machine, partly in section; Figs. 2 and 3 are, respectively, an enlarged front and top view of the looper driving devices showing the machine operating as a twothread machine; Fig. 4 is a top view of the lower thread looper drive forming a self-container unit; Fig. 5, a front view of the lower thread looper with drive and feeder; Fig. 6, a sectional side view of one of the fixed eyes for the lower thread and of the adjusting device of the lower thread looper unit; Figs. 7 and 8 are, respectively, a side view and cross section of the lower thread looper with needle thread loop; Fig. 9 is a top view, partly in axial section, of the entire looper and auxiliary looper arrangement; Fig. 10, a side view, particularly of the auxiliary looper; Figs. 11 and 12 are, respectively, a top and front view of the looper arrangement and drive if the machine is used as a three-thread machine; Figs. 13 to 16 show progressively, seen from the front, the production of a two-thread seam; Figs. 17 and 18 are, respectively, top and bottom views of this seam; Fig. 19 is a top view of the loopers at work; Figs. 20 to 22 show progressively, seen from the front, the production of a three-thread seam; Fig. 23 is a diagram thereof; Fig. 24, a side view of Fig. 20; and Fig. 25, a top view of the loopers at work.

Referring to the drawings, the sewing ma- 5 chine according to the invention is driven in the usual manner by a main shaft I extending horizontally in the lower portion of the frame 2 from one side to the other. The seam is produced in the known way by the needle 3 and the two loopers 4 and 5.

The lower thread looper 4 forms with its drive a self-contained unit (Fig. 4) and is disposed in a bracket 3 secured to the base plate 1 of the machine. The rotation of the main shaft l, by means of an eccentric having a spherical surface, a guide fork 3 and a ball pivot I0, is transmitted first to a vertically oscillating driving lever l l which oscillates with its long bush-like boss l2 about an axis l3 (Figs. 3, 4 and 5) fixed in the bracket 4. To the boss l2 a lever arm I4 is clamped by means of the screws l5 disposed in the gripping jaws ii of the radially split boss ll of the arm l4 which can be laterally displaced or turned after the screws l5 are loosened.

The lever arm I4 is connected by a joint IS with an interposed lever I9 which, with its long bush-like boss 20, oscillates about an axis 2| of the lower thread looper 4 also positioned in the bracket 6.

. The lower thread looper 4, with its lever 22, is secured axially dlsplaceable and rotatable to the boss 23 of the intermediate lever I 9. The boss of the lever contains for this purpose a radial gap clamped removably, by means of screws and gripping jaws, to the boss 20 of the intermediate lever I9 in the same manner as the lever arm l4 to the boss l2 of the driving lever H.

Owing to the articulated drive l4, I8, IS, the lower thread looper 4, after its advance, stands still until the needle 3 moves up again and the needle loop has opened, the duration of this stoppage being capable of variation by adjusting the lever arm H. The regulation of the lower thread 23 takes place from the lower thread looper lever 22, the arm 24 of which is disposed on the other side of the lever 22, being provided for this purpose (Fig. 5) with a thread eye 25 which cooperates in the oscillation of the lever, is adjustable and can be set as to height in the arm 24 and fixed by a. screw 26.

The thread eye 25 cooperates with two stationary thread eyes 21 disposed on both sides of its path and secured by a common base plate 28 to the bracket 6. These eyes 21 can also be adjusted as to height (Fig. 6), and the base plate 23 contains for this purpose a longitudinal slot 33 to permit the passage of the fastening screw 23.

To prevent-the lower thread 23 from coming in frictional contact with the needle thread loop 3| disposed transversely to it, the back of the lower thread looper 4 is fitted with a rib 32 (Figs. 7 and 8) which keeps the loop 3| from touching the lower thread 23 moving in the groove located above the rib 32.

The entire mechanism of the lower thread looper 4 can be turned about a vertical axis and adjusted so that the lower thread 23 is brought safely in front of the needle 3 and rapid adjustment to various thicknesses of the needle can be effected. For this purpose, the pin 33 (Fig. 9) passing through the base plate 1 of the machine frame 2 serves as axis of rotation for the bracket 6, the adjustment taking place by means of the two screws 34 which can be tightened from below and pass through the slots 35 of the base plate I, the slots being curved about the pin 33 (Fig. 6).

The looper 5 moving over the table 36 is driven directly from the end of the main shaft l positioned near the stitch-forming device (Fig. 11). For this purpose, the end of the shaft carries a crank 31 which. by means of a connecting rod 38 and the ball pivots 89, moves the driving lever 5 4| up and down thereby oscillatingly rotating it about the looper axis 40. The lever 4| is provided with a bush-like boss 42 for swinging about the axis 40, the boss being firmly positioned in the eyes 43 of the base plate I; To the 10 boss 42 is clamped the lever 44 holding the looper 5 and having a radially split boss 45, the fixing being effected by means of the jaws 46 and the screws 41. After the screws 47 have been loosened the lever 44 can be axially displaced as 15 well as turned.

If the machine is used as a two-thread machine, as shown in Figs. 2 and 3, an auxiliary looper is used (Fig. 10) which with its axial shank is located in the center of its axis 49 os- 20 cillatingly rotating in the bosses 50 of a carrier 5i and thus turning oscillatingly the auxiliary looper 48. It is driven directly from the looper lever 44 by means of a connecting-rod 52 engaging the back of the lever 44 and being connected 25 with the lever 53 located on the looper axis 49. The balls 54 serve as the connection. The carrier 5i is secured on top to the boss 55 of the main shaft l slightly below the table 36.

All parts below the table 36 are thus freely 30 accessible.

In order to sew on the same machine with three threads, provision has been made to replace the auxiliary looper device by a thread guide for the third thread es. 215' For this purpose, the carrier 5! together with the entire auxiliary looper device (Fig. 11) can be taken off owing to the fact that the attachment is removably secured, for instance by the screws 51. Moreover, a carrier 58 is provided 40 which is constructed so that it can be secured in working position in lieu of the member 5|. The carrier 58 possesses two stationary thread eyes 59 disposed on both sides of the path of a thread eye 60 arranged on the looper lever 44 and con- 45 sequently adapted to swing up and down. This eye 60 may be permanently attached to the lever 44 or fitted to it only when three threads are used in working.

Figs. l3-19 show the formation of the stitch 50 of a two-thread sewing machine and Figs. 20-25 show the formation of the stitch of a threethread sewing machine.

Fig. 13 shows in front view the link side end position of the looper 5. The needle 3 travels 55 downwards from this position and penetrates into thread triangle carried up by the looper 5 as shown in Figs. 14 and 17.

The looper 5 swings immediately back and fills the thread triangle. Also the looper 4 will swing back (to the left) and permits thereby the needle thread knot to finally fall.

Fig. 17 shows the position in top plan view of the various parts shown in Fig. 13 together with the seam, the last thread triangle being from the top. Fig. 18 shows the seam from the bottom.

Fig. 14 shows the needle in its deepest position, whereby the looper 5 still swings back somewhat while the looper 4 now moves against the needle and will enter in its thread knot, when it moves upwardly.

Now the looper 5 will also swing forward, that is, against the looper 4 which swings still further outwardly and will take off the thread by means of a point as shown in Fig. 15. This thread is taken upwardly as shown in Fig. 16, so that the cycle can be repeated in that the thread triangle is again built up.

Fig. 19 is a top view of Fig. 15.

The auxiliary looper 48 holds the looper thread 23 as shown in Fig. 15 and as already described it holds it so long until the needle thread has been pulled.

The positions of the various elements of Figs. 20-25 correspond exactly to Figs. 13-19. The looper 5 is merely replaced by a thread guiding looper and the auxiliary looper is removed therefrom.

From the figures it is apparent that in a three thread scam the thread of the gripper 5 is brought to the needle instead of to the thread of the looper 4 as in a two thread seam. The needle then penetrates through the loop of the looper thread while the looper thread of the looper 4 is secured on the edge of the material as seen in Figs. 21 and 23.

I claim:-

1. In a sewing machine of the type described, means whereby said machine may be converted at will to sew with two threads or with three threads, comprising a removable auxilary looper unit to permit sewing with two threads and a thread guide adapted to replace the said auxiliary looper unit to permit sewing with three threads.

2. In a convertible sewing machine according to claim 1, a table, a main shaft, a stitch-forming device, a bearing for the main shaft arranged outside the stitch-forming device, a drive therefor, and acarrier adapted to support the said auxiliary looper and its drive and removably secured below the table to the said bearing.

3. In a convertible sewing machine according -to claim 1, a table, a looper adapted to move thereover, a vertically oscillating arm forming part of the said looper, a thread eye disposed on the said arm, an exchangeable thread guide adapted to replace the said unit to permit sewing with three threads and consisting of a carrier and two thread eyes fixed thereto, the said stationary thread eyes being disposed on both sides of the said vertically oscillating thread eye.

4. An overcast seam sewing machine for sacks, carpets and bed covers, having an upper and a lower looper, a base plate, a longitudinally extending main drive shaft, a lower looper arrangement driven thereby, and including a thread regulating means, and a support carrying the lower looper, said support being secured to the said base plate of the machine so as to be capable of being rotatable and adjustable about a vertical axis.

5. A sewing machine in accordance with claim 4, including also an intermediate lever, and an intermediate shaft, the lower looper being controlled by said intermediate lever by means of said intermediate shaft, means whereby said intermediate lever may be adjusted axially, as well as by rotation about its shaft, and secured, and means whereby said lower looper may be adjust able laterally and also rotatably about its axis.

6. A sewing machine in accordance with claim 4, including also an intermediate lever, and an intermediate shaft, the lower looper being controlled by said intermediate lever by means of said intermediate shaft, means whereby said intermediate lever may be adjusted axially, as well as by rotation about its shaft, and secured, and means whereby said lower looper may be adjustable laterally and also .rotatably about its axis, said means comprising levers having hubs upon which the adjusting elements are mounted. I

7. A sewing machine in accordance with claim 4, wherein an auxiliary looper is provided for sewing with two threads, said looper being removable as a whole together with its drive means and its support, and replaceable by a thread 10 guide which permits sewing with three threads.

8. A sewing machine in accordance with claim 4, wherein an auxiliary looper together with its drive means is mounted upon a block which is removably secured below the table plate upon 15 the support of the main shaft, lying at the outer side of the stitch-forming means.

9. A sewing machine in accordance with claim 4, wherein an auxiliary looper is provided which has a rounded acute angled configuration at its 20 knee.

10. A sewing machine in accordance with claim 4, wherein a thread guide is provided which is exchangeable for an auxiliary looper means for sewing with three threads, and consists of two 25 stationary thread eyelets mounted upon a block, a thread eyelet mounted upon a looper, which swings over the table plate, said stationary eyelets being arranged on both sides of said movable thread eyelet and on both sides of a lever which swings up and down.

11. In a convertible sewing machine according to claim 1, a table, a connecting rod, an arm arranged on the axis of the auxiliary looper unit, a looper moving over the said table, and an arm forming part of the said looper and adapted to drive directly the said auxiliary looper unit by means of the said connecting rod. I

12. A sewing machine in accordance with claim 4, in which a lower looper lever and an arm are 40 provided and the arm extending from the lower looper lever, a thread receiving eyelet for the lower thread arranged upon said arm, said eyelet having an axis of rotation, and means whereby said eyelet is capable of adjustment with respect 45 to its axis of rotation.

13. A sewing machine in accordance with claim 4, wherein stationary thread eyelets and a swinging thread receiving eyelet are provided, the stationary eyelets being provided on each side of 50 the swinging thread receiving eyelet in order to regulate the lower looper thread, and means whereby said stationary eyelets are capable of adjustment up and down.

14. A sewing machine in accordance with claim 55 4, wherein the lower looper has a longitudinally extending rib defining a groove arranged laterally of the looper over which travels the needlethread loop formed in sewing, while one strand of the looper thread passes through the groove 60 defined by the rib.

15. A'sewing machine in accordance with claim 4, comprising a looper lever for the upper looper and having a driving lever, said driving lever having a hub, and said looper lever being rotatably c5 and laterally adjustable upon the said hub.

16. A sewing machine in accordance with claim 4, in which an auxiliary looper, and a push rod are provided, the auxiliary looper being driven directly by the push rod.

FRITZ EBERT.

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