US1252745A - Hemstitch sewing-machine. - Google Patents

Description

H. UNGER.

HEMSTITCH SEWING MACHINE. APPLICATION FILED JAN. 5, 1916- 1,252,745 Patented Jan. 8, 1918.

2 SHEETSSHEET I.

H. UNGER.

HEMSTITCH SEWING MACHINE.

APPLICATION FILED JAN. 5. 1916.

1,25Q,7%5. Patented Jan. 8,1918.

2 SHEETSSHEET 2.

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HUGO UNGEIR, OF BERLIN, GERMANY, ASSIGNOR TO THE FIRM OF LINTZ & ECKHARDT, 0F BERLIN, GERMANY.

HEMSTITCI-I SEWING-MACHINE.

Specification of Letters Patent.

Patented Jan; 8, 1918.

Application filed January 5, 1916. Serial no. 70,435.

To an whom it may concern Be it known that I, HUGO Uncnn, a subject of the King of Saxony and German Emperor, residing at 8 lVilhelin Stolzestrasse, Berlin, Germany, have invented certain new and useful Improvements in Hemstitch Sewing-Machines; and i do hereby declare the following to be a full, clear, and exact description of the invention.

My invention relates to hemstitch sewing machines and more particularly to the piercer and means for changing the stroke of the same, so that the piercer may remain in the fabric when the direction of feed is changed. Heretofore when the direction of feed was changed after a straight seam was made, the new seam was not in the proper relation to the other seam and the corner of the two seams was not sewn exactly. This results from the fact, that the fabric in turning often is shifted with relation to the needles, so that the needles and the piercer lifted to the upper position before the fabric was turned, cannot enter in their downward movement exactly in the holes, made previously in the fabric.

According to the invention an exact joining of the new seam is obtained by the fact, that in turning the fabric the stroke of the piercer is altered in such a manner, that the piercer remains in the fabric. The fabric therefore may be turned but it cannot be shifted.

Means are provided for effecting the change of the stroke of the piercer without the help of the hands, which are necessary to guide the fabric.

Another ob ect of the invention is to provide means for locking the presser foot in its upper position when the stroke of the piercer has been changed.

A form of construction of the invention is shown as an example in the accompanying drawings.

Figure l is a front view of the machine; Fig. '2 a side view. partly in section on line AB of Fig. 1; Fig. 3 a plan View; Figs. 4 to 6 are details of the essential parts of the machine in different positions; Fig. 7 shows a modification.

The two needles a a which can be moved up and down and spread in a known man ner, are fastened on the needle bars I) b, hinged to the head 12 This head is provided with which engages the fork a of the bar a, acted upon in a known manner by a cam, notshown in the drawing. The presser (Z is fastened on the lower end of the presser bar cl, the upper end of which is pivotally connected with the sleeve (F. A pin d of this sleeve engages the vertical bar 7 which can be moved up and down in the guides f f. A lateral projection f of this bar is acted upon by the lower arm t of a lever 15, pivoted on the stud 25 The upper end of this lever is provided with a roller i resting against the cam f. This cam is fixed on a counter shaft 7" which is journaled in the arm 7" and connected with the main shaft 0 by suitable gearing (not shown) adapted to drive the counter shaft at a slower speed than that of the main shaft, the purpose of which will be hereinafter explained. The shape of the cam f is such that when its raised portion engages the roller of the arm 1., the latter is suddenly lowered and the arm Lb, bar 7', sleeve d and presser bar d are To quickly return these parts to.

lifted. their initial positions, a spring which tends to depress the bar f, is connected at one end to the bar 7' and at the other end to the guide f.

The lower part of the presser'bar (Z' is provided with a lateral arm or loop (1 which is actuated by the lower arm of the lever (Z pivotally arranged on the stud d Against the upper beveled arm of this lever rests a lateral projection g of a vertical bar g, movable in the guides g and 9 The upper end of this bar is provided with a lateral projection 9 resting against the under side of a lever 9 pivotally arranged on the stud 9 The free end of this lever rests on the cam 9 fixed on the main shaft 0. A spring fixed at one end to the frame of the machine and bearing with the other end against a projection g of the bar 9, tends to lift this bar. When the cam g rotates the bar 9 is moved up and down and by means of the lever (Z the presser bar d with the presser (Z is shifted to and fro, while it is moved up and down at the same time by the action of the cam f on the lever 15 and the spring f on the bar f, the arrangement being such, that the fabric h is fed after each third stitch of the needles.

Between the needles a a the piercer 2' is arranged, which is detachably fastened to the bar 71. This bar is connected to the arm this lever carries a pin a engaging a camcylinder 0 fixed on the main shaft 0. By the rotation of this cam cylinder the lever n is rocked and the bar is and the piercer i are moved up and down.

Normally the pin a lies in the right end of the cross arm of the L shaped slot m, as

shown in Figs. 2 and 5, and in this position of the pin a the stroke of the piercer 2 is such, that the piercer in its upper position is out of the fabric h, as shown in Figs. 1 and 2, so that the fabric may be shifted by the presser (Z. If the direction of the seam is to be changed, the stroke of the piercer is diminished to such a de 'ree, that the piercer also in its upper position remains in the fabric, as shown in dotted lines Fig. 6. For this purpose on the underside of the bed-plate 39 a bell crank lever q is arranged, rotatable on the stud 9. This lever is con nected by the rod r to another bell crank lever r, pivotable on the stud r. The lever r is connected by the rod r with the lever Z. If the lever Q is moved in the direction of the arrow, shown in Fig. *2, by the knee of the person using the machine, the lever Z, in the lower position of the bar is and piercer 7', is moved toward the right hand into a hole 6 of the plate 6', as shown in Fig. 6.' The pin a in the movement of the lever 12 is moved in the vertical part of the L shaped slot while the lever Z and the parts connected with it'are maintained in their position, until the pin n reaches the end of the slot. In the further upward movement of the pin '12 the lever Z, the bar and the piercer 2' are lifted against the action of the spring k But this upward movement of the bar 70 and the piercer is so small, that the point of the piercers is not lifted out of the fabric, but remains in the same, as shown in dotted lines Fig. 6. In this position the fabric may 'be turned while the presser is in its upper position, but it cannotrbe shifted with relation to the needles. The pin 72 in its following downward movement moves firstly idle in the vertical slot until it reaches the lower end of the same, whereupon the lever Z and the piercer 2' are moved downward. until they reach the position, shown in full lines in Fig. 6.

The presser (Z must be lifted, if the fabric is to be turned. This is preferably effected automatically by changing the stroke of the piercer. For this purpose the following rgeans are provided. To the bent lever r a second rod r isfastened which runs nearly parallel to the rod r and is supported by lever.

the projection s of the frame. The free end of this rod rests in the lower position of the presser against the arm i of the lever Z. If the presser is in its upper position, while the needles and the piercer are in the lower position, the free end of the rod r can be moved by turning the lever 9, under the lifted arm Z of the lever t, as shown in dotted lines Fig. 4, so that the lever t, the bar 7 and the presser (Z are locked in the upper position. In the mean time the rod r is moved along for changing the stroke of the piercer, as above described. In this locked upper position of the presser, the fabric can be turned around the piercer remaining in thefabric, and the corner of the seamcan be sewn exactly, as the fabric cannot be shifted in this position of the presser. By releasing the lever Q the rods r r r are returned by the spring it into normal position, so that the rod r releases the lever t and the presser d and. the lever Z is brought into the position shown in full lines in Fig. :2. The piercer 2' therefore will have its full stroke.

In the modification shown in Fig. .7 the lever Z carries a pin Z engaging an inclined slot 41 of the lever 12. If the lever Z is drawn to the left hand by the 10d r until the pin Z rests against the end of the slot, the stroke of the piercer-bar I: will be di minished, the pin Z working on ashorter lever arm. The piercer therefore will remain in the fabric also in its upper position.

I claim as my invention:

1. In a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a piercer arranged between the needles, means for reciprocating the piercer, feeding mechanism for the fabric including a presser, and means for changing the stroke of the piercer and holding it in the fabric during the upper position of the presser.

2. In a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a piercer arranged between the needles, means for reciprocating the piercer, feeding mechanism for the fabric including a presser, means for changing the stroke of the piercer and holding the point of the latter below the fabric, and means for locking the presser in-raised position.

3. In a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a piercer arranged between the needles, means for reciprocating-the piercer, feeding mechanism for the fabric, a lever pivotally connected at one end with the piercer, a bell crank lever slidingly connected to the other end of the aforesaid lever, and a camon the machine shaft for actuating the bell-crank 4. In a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a piercer arranged between the needles, means for reciprocating the piercer, feeding mechanism for the fabric, a lever pivotally connected at one end to the piercer and provided on its other end with an L-shaped slot, a bell-crank lever having a pin engaging said slot, a driving shaft, and means on the latter for rocking the bell-crank lever.

5. In a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a piercerarranged between the needles, means for reciprocating the piercer, feeding mechanism for the fabric, a lever pivotally connected at one end to the piercer and provided in its other end with an L-shaped slot, a bell-crank lever having a pin engaging said slot, a driving shaft, means on the latter for rocking the bell-crank lever, and means for changing the position of the slotted lever relatively to said pin.

6.1m a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a pierccr arranged between the needles, means for reciprocating the piercer, means for changing the stroke of the piercer, feeding mecha nism for the fabric including a vertically reciprocating bar, and means automatically operated by the stroke changing means for locking the said bar in raised position.

7. In a sewing machine, the combination of needle bars, means for reciprocating the same, needles carried by the bars, a piercer arranged between the needles, means for reciprocating the piercer, feeding mechanism for the fabric including a vertically reciprocating bar, a movable rod for locking the said bar in raised position, a bell crank lever arranged on the under side of the ma chine, and means connecting the movable rod with the bell crank lever.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing Witnesses.

HUGO UNGER.

Witnesses:

HENRY HASPER, LILLI F RANK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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