US2594523A - Bobbin casing retaining means - Google Patents

Description

April 1952 E. URSCHELER 2,594,523

BOBBING CASING RETAINING MEANS Filed Nov. 12, 1946 2 SHEETS-Sl-IEET 1 Izzv ezzrbaz Patented Apr. 29, 1952 BOBBIN CASING RETAINING MEANS Emil Urscheler, St. Gallen, Switzerland, assignmto Brutsch & 00., Zurich, Switzerland Application November 12, 1946, SerialNo.'709,266 In Switzerland February 28, 1946 The present invention relates to bobbin casing retaining means for sewing machines of the type comprising a rotary hook or loop taker revolving about an axis and provided with a chamber adapted to receive a bobbin case holder. In sewing machines of this type it is customary to utilize rotary hooks having either a closed or an open raceway.

In utilizing a rotary hook having open raceway the bobbin case holder lies with play in the chamber provided in the rotary hook and is loosely held in the open raceway of the hook generally by a hinged plate.

This drawback or defect does not exist when a rotary hook having a closed raceway is utilized. However, this latter type of rotary hook is more complicated to make and, therefore, more expensive.

Accordingly the present invention has for an object to provide an arrangement on a sewing arm of the sewing machine of the type referred to above permitting the use of the same bobbin casing with either type of rotary hook, namely, one with a closed raceway and also one with an open raceway.

An additional object is to provide dual pivoted means for holding the bobbin casing against rotation in a rotary hook having a closed raceway and for both holding the bobbin casing in the open raceway of a rotary hook of this type while simultaneously holding the casing against rotation relative to this latter type of rotary hook.

One preferred embodiment of the invention is illustrated by way of example in a sewing ma chine with a free sewing arm in the accompanying drawing, in which:

Fig. 1 is a vertical cross-section through the free sewing arm along the looper axis, embodying a rotary hook having a closed raceway;

Fig. 2 a plan-view of the structure shown in Fig. 1;

Fig. 3 a vertical cross-section analogous to Fig. 1 showing a rotary hook having an open raceway,

Fig. 4 a plan-view of the structure shown in Fig. 3.

The looper device as shown in the drawing has the rotary hook I, which is held by means of a sleeve 2, in a hollow shaft 4 rotatably supported in the free sewing arm 3 of the machine. The sleeve 2 is provided with a projection 5 which engages with a complementary sleeve 6 fixed in the hollow shaft 4, in such a way that the rotary hook I can be fixed only in one definite position in the hollow shaft 4. The two sleeves 2 and 6 are connected to each other by a screw I. The

1 Claim. (Cl. 112-181) shaft 4 may be driven byany desired means, such as a sprocket and chain or gearing,

The bobbin case 8, in which the thread bobbin is located, has on its periphery the annular rib 8 which lies in the closed raceway II] of the rotary hook I (Figures 1 and 2) or in the open raceway I0 (Figures 3 and 4). In the case of the rotary hook with the closed raceway (Figures 1 and 2) a ring I9 is removably secured to the open face of the rotary hook in any suitable manner in order to provide for the insertion of the bobbin case 8 into the raceway II] of the rotary hook.

The bobbin case 8 has a diametrical slot or recess II, in order that it may be secured against turning when the rotary hook I rotates.

On the casing of the sewing machine, that is, on the wall of the sewing arm there is pivotally mounted a retaining arm I2 which is provided with a nose I3 and also a boss I2 which, when the arm is swung from the position shown in Figure 1 to the position shown in Figure 3, engages against the bobbin case 8 to hold it in the chamber formed in the rotary hook I, while the nose I3 enters into the slot or recess II to hold the bobbin case 8 against rotation in the rotary hook I, as shown in Figures 3 and 4. A leaf spring I4, fixed on the casing part 3, has two holes I5 therein, into either of which a pin IE on the arm I2 can be brought into engagement in order to keep the arm I2 in either the inoperative position of Figs. 1 and 2 or the operative position of Figs. 3 and 4. During the formation of each stitch it is necessary that the needle thread loop pass around the bobbin case 8 and between the case and the boss I2, and accordingly clearance between the boss I2 and the bobbin case is provided, as shown in Fig. 3.

When using a rotary hook with a closed guiding raceway II], the retaining arm I2 remains in the position shown in Figs. 1 and 2. On the other hand rotation resisting arm II, which is pivoted on the wall of arm 3, has its nose I8 inserted into the slot or recess II to prevent ro tation of the bobbin casing.

It is clear, therefore, that with the previously described structure the sewing arm is adapted to interchangeably receive either a rotary hook having an open raceway or a rotary hook having a closed raceway. The position of the rotary hook is definitely determined because of the coupling projections on the sleeves 2 and 6. Furthermore. the bobbin casing 8 will be positively prevented from turning relative to the rotary hook either by the arm I2 when the rotary hook has an open raceway or by the arm I! when the rotary hook has a closed raceway. It is clear, therefore, that the arm I 2 has a dual function to retain the bobbin casing in the chamber of the rotary hook and also to prevent its rotation relative to the rotary hook. The arm I1, 01 course, being utilized with a rotary hook having a closed raceway merely prevents the bobbin casing from rotating relative to the rotary hook.

What I claim is:

In a sewing machine having a sewing arm, a 10 shaft rotatably supported in the arm and adapted to alternately receive rotary hooks having open and closed raceways respectively and which in turn are adapted to receive a bobbin case having a diametral slot therein, means for holding a bobbin case in either of the rotary hooks against relative rotation therein and for retaining same in the open raceway hook, said means comprising an arm pivoted on the sewing arm and having a nose thereon adapted to engage in the diametral slot in the bobbin case when supported in the closed raceway, and a retaining arm pivoted on the sewing arm and having a nose adapted to fit in the diametral slot in the bobbin case when supported in the open raceway and a projection thereon forming an abutment to limit axial movement of the bobbin case in the rotary hook, and a locking device for holding the retaining arm in either the disengaged position or engaged with the bobbin case in the rotary hock having the open raceway.

EMIL URSCHELER.

REFERENCES CITED The following references are of record in the

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