DE2222554A1 - Fabric presser foot for sewing machines - Google Patents

Description

Wifctetiberge, April 27, 1972

Applicant: VEB sewing machine works Wittenberge

29 Wi t t e η b e r G e Bad Wilsnacker Strasse 48

Presser foot for sewing machines

The invention relates to a presser foot for Sewing machines with low mass and movable soles in which the upper part of the presser foot with the presser foot sole is detachable is connected and a quick change of different sole designs is possible without special aids, the upper part of the presser foot remaining on the presser bar can.

Designs of presser feet are already known which the sole is movably and releasably attached to the upper part by means of a screw. Other versions allow this The bolt fastened in the sole snaps into a groove in the upper part, which is secured by a leaf spring or a different version solves the problem of interchangeability with simultaneous mobility of the sole due to the snapping of a fixed bolt located in the upper part transversely to the sewing direction in a corresponding resilient groove of the presser foot sole itself or designed as a joint or spring-loaded locking components,

In other known constructions, the resilient elasticity of a plastic material is used to create a plastic pin to snap into a recess in the presser foot sole. This construction has the disadvantage that with support the sole of the presser foot exclusively on the embedment of the pin

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ORIGINAL INSPECTED

the dreaded cold flow occurs and an exact positioning of the sewing foot to the needle hole is not possible in the long run is.

In addition, known designs of presser feet with movable and exchangeable soles are predominant thick-walled, with the upper part made of ffiaasive die-cast, Malleable cast iron, sintered, profile or thick sheet metal materials and the sole can be made of the same material as well as plastic (partly with a steel insert).

This type of presser foot has the pocket part that is due to the high conveyor speeds of mowers running at high speed due to the large mass of the sole and upper part, considerable inertia forces act on the transport gear cause rapid wear and tear and reduce the intended effect of pressing the material onto the feed dog.

In addition, with known facilities, additional costs arise from components that are necessary for hanging and locking the Sole are required. Sometimes even tools are necessary for the change process.

To remedy these deficiencies, it is proposed according to the invention, to significantly reduce the mass of the sole and upper part and to connect both parts without additional components in such a way that 3 an exchange of the sole is possible without tools.

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Another purpose of the invention is to provide a presser foot to create, whose toes in the lifted state of the presser bar without tools such. B. springs, at an angle at the front stand upwards so that the material can be easily pushed in by the operator.

The reduction in mass is achieved according to the invention in that the upper part is made of a lightweight material, preferably made of plastic and the sole of thin sheet metal less than 0.6 mm thick. The sole is bent in such a way that that their shape of the function of the Stoffandrückeiis on the conveyor is sufficient and at the same time for attachment serves to accommodate the sole of the upper.

With the upper part, which is or is not attached to the pressing rod in the conventional manner with the aid of a prism can be a detachable part of the presser rod, the sole is rigidly connected. The natural elasticity alone of the material of the upper part allows the mobility of the sole. The mobility is increased by a Recess in the upper part, which must result in such a thin load-bearing cross-section that this instead of an otherwise common one Scharnicres with the axis transverse to the sewing direction can effectively v / ground. The center of rotation of the hoof foot movement is then in the neutral flexible fiber of the thin load-bearing cross-section created by the recess. Since the pole of rotation is in

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immediate vicinity of the intended for the passage of the needle Breakthrough is laid in the sole, one achieves greater security against the impact of the needle the edge of the needle hole when sewing over cross seams.

According to the invention, the toes stand up in such a way that that the upper part made of elastic material is given a corresponding design.

j Several exemplary embodiments are intended to elucidate the invention in more detail

! purify. In the drawing represent: i

! Fig. 1: the complete presser foot, its sole mobility is achieved through a recess in the upper part, in the view against the sewing direction,

'Fig. 2:' the side view of Fig. 1 in the sewing position,

Fig. 3: The complete presser foot in the view against the sewing direction, its sole mobility through a recess is reached in the upper part and the sole is equipped with a resilient operating tongue is,

FIG. 4: the side view of FIG. 3,

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Fig. 5: an exchangeable sewing foot sole in an oblique view for the embodiment according to FIG. 2,

Fig. 6: an exchangeable presser foot sole at an angle view for the embodiment of Fig. 4,

Fig. 7: an exchangeable presser sole in an oblique view with a fork-shaped guide on the upper part of the presser,

Fig. 8: an exchangeable cloth presser sole in an oblique view with a lateral guide on the upper part of the presser presser,

Fig. 9: a presser upper part in direct combination with the press rod,

t *

Fig, 10: The presser foot according to Fig. 2 in the ventilated state Press bar.

The presser foot shown in Figures 1 to 4 consists of the upper part 1, preferably made of plastic, a prism 2 for attaching to the here .not shown Has presser rod and the sole 5. This upper part 1 has a larger recess 3, which the load-bearing cross-section 4 so that the natural flexibility and elasticity

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of the material are sufficient to ensure the mobility of the thin sheet metal sole 5 to ensure an angle 6, which is required to overcome transverse seams during the sewing process.

The upper part 1 also contains a recess 7 into which a tab 8 of the sole 5 can snap.

In Figures 5 and 6 examples of interchangeable soles are shown, in which both the tab 8 to snap in as well the spur 14 required for reverse sewing can be seen. Ensuring lateral guidance of the removable sole through a web 10, which lies in a recess 12 of the upper part, can be seen from FIGS. The side Fixation can also, as shown in FIGS. 7 and 8, by means of lateral webs 15 and by lateral tabs 16 can be achieved.

To replace the thin sheet metal soles 5, the catch 7/8 in FIGS. 1 and 2 is released by pushing up the tongue 11 and the sole 5 pushed backwards out of the guide. In Figures 3 and 4, the detent 7/8 is released by pressing down the resilient operating tongue 13- Another sole 5 is then only with the curved index finger pushed onto the upper part 1 from behind until the

Latch 7/8 jumps in. However, designs are also conceivable,

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in which the tabs 8 protrude so far that it can be disengaged by lifting with the pingernail.

According to Figure 9, the upper part 1 is modified so that it is immediately can be pressed or glued into the hollow press rod 19 with a pin 18. The attachment the sole 5 takes place as described above.

From FIG. 10, it can be seen how the design of the flexible upper part 1 provides an angle 17 that defines the inclination the sole 5 characterizes, is realized.

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Claims (7)

Patent claims: 1. Presser foot for sewing machines with low mass and movable sole and a form-fitting, detachable connection between a flexurally elastic presser upper part and a thin sole, characterized in that that in the load-bearing cross-section (4) of the upper part of the fabric presser (1) for the mobility of the sole receptacle (9) a recess (3) is provided at an angle (6). ! 2. Presser foot according to claim 1, characterized in that j that the presser foot sole (5) is covered on both sides with a cloth (8) engages in recesses (7) of the sole receptacle (9). 3. Presser foot according to claim 1 and 2, characterized in that the presser foot sole (5) is a replacement process has serving tongue (11). 4. Presser foot according to claim 1 and 2, characterized in that the presser foot sole (5) has a backward direction resilient operating tongue (13) carries. 5. Presser sole according to claim 1 and 2, characterized in that that the sole receptacle (9) with the sole (5) is inclined upwards at the front. - 9 209849/0732 6. Presser foot according to claim 1 and 4, characterized in that the presser foot sole (5). with side bars (15) is provided. 7. Presser foot according to claim 1 and 4, characterized in that the presser foot sole (5) Mt lateral flap (16) is provided. 8, presser foot according to claim 1, characterized in that that dag upper part (1) for holding the sole (5) directly with the hollow press rod (19). connected is.