EP3655578B1

EP3655578B1 - Sewing machine for decorative and functional seams

Info

Publication number: EP3655578B1
Application number: EP18749884.5A
Authority: EP
Inventors: Ferruccio Perego
Original assignee: Complett K&s Srl
Current assignee: Complett K&s Srl
Priority date: 2017-07-18
Filing date: 2018-07-13
Publication date: 2022-11-09
Anticipated expiration: 2038-07-13
Also published as: WO2019016840A1; IT201700081389A1; EP3655578A1

Description

The present invention relates to a programmable sewing machine, suitable for making decorative and functional stitching in general.
More particularly, the invention refers to a programmable sewing machine, specifically designed for stitching so-called "running", which is generally used, for ornamental purposes, in tailored dresses, particularly in the beading of the lapels of the jackets, coats, skirts, as well as trousers, handbags, gloves and similar items.
As is known, the running stitch (characteristic of the hand-sewing) is formed by a single thread, of prefixed length (called "needle punched "), which crosses the flaps of the fabric along its entire length, so as to be arranged alternatively on the straight and on the reverse side of the garment being sewn, so that the running-stitches, of variable and adjustable length, are alternately visible on one and on the other side of the fabric to be sewn. The traditional sewing machines, which to make running-stitch, such as those described, for example, in the prior patent documents EP 1233094 and EP 1233095 , substantially employ a vertical axis needle, arranged perpendicular to a support plate, where the item to be sewn is placed. The needle can be actuated with motion alternating along its axis, in such a way that it cyclically crosses the piece to be sewn, bringing, from time to time and, alternately, above and below the support plane, a needle loop of the needle-punched used for sewing; an upper end of the threaded needle-punched is pinched on the piece in seam, while the other end is left free. Below the support plane, a thread recovery wheel, arranged in a plane substantially parallel to the axis of the needle is envisaged, which is composed of a fixed part, with a circular development, and a revolving part, which can be actuated with rotary motion and in synchronized way with the movement of the needle, with respect to the fixed part.
In the fixed part of the wheel there is a storage for the collection of the recovered thread, while the rotating part carries peripherally a lower hook or crochet, which, following the rotation of the wheel and the movement of the needle, hooks the thread loop below the support plane and recovers the portion of thread extending from the lower crochet to the free end of the needle-punched, passing it into the collection containment.
In particular, the containment comprises a peripheral circular channel, open in correspondence of an interruption of the fixed part of the wheel and placed on the lateral surface of the aforesaid fixed part, such that a flow of pressurized air is blown into the channel according to a direction in accordance with the direction of thread loading in the channel.
A further hook or upper crotchet, which is arranged above the support plane, has the function of hooking the thread loop carried by the needle above the support plane and retaining it, while the thread is loaded into the storage of the recovery wheel.
The machine is also provided with means for moving the section of thread which extends from the piece to be sewn to storage of the thread, away from the trajectory of the needle, means for moving the same section of thread towards the trajectory of the needle and thread loading means, suitable to retain the branches of the thread loop hooked by the lower crotchet.
These machines, over the years, have proved to be susceptible of improvement, mainly aimed at improving the quality and precision of the stitching, as well as avoiding having to continuously adjust the means of restraining and handling the thread, depending on the type of yarn used (which can be "light" or "heavy", depending on the diameter chosen for sewing the garment).
In particular, depending on the materials and threads used, it is increasingly problematic to manage the ornamental effect of the seam, due to the occurrence of excessive tensions, which on certain occasions are undesirable in an ornamental stitch which is the "stitch" by hand of this type of sewing machine.
Furthermore, it would be extremely expensive to manually adjust the mechanical members of the machine each time yarns of different diameter and/or thickness are used.
A sewing machine for decorative and functional seams, with technical features that can be considered the closest state of the art to the following invention, features that are present in the preamble of the attached claim 1, are described, for example, in the documents FR2322953A1 (D1) and US3207107A (D2).
In this regard, within the aforementioned requirements, the object of the present invention is to provide a sewing machine for making decorative and functional seams, which is extremely versatile and suitable for avoiding excessive thread tensions, especially in the case of an ornamental stitch such as the "hand stitch", where they are extremely undesirable.
Another object of the present invention is to provide a sewing machine for making decorative and functional seams, which allows the ornamental effect to be managed to the best of the possible conditions and which is extremely safe and reliable.
A further object of the invention is to provide a sewing machine for making decorative and functional seams, which has a substantially simple construction structure, compared to traditional machines, by virtue of the advantages obtained.
These and other objects are achieved by a sewing machine for making decorative and functional stitches according to the attached claim 1; other detailed features of the machine are described in the subsequent claims.
Further objects and advantages of the present invention will be more evident from the following description, referring to an exemplary and preferred but not limiting embodiment of the sewing machine for making decorative and functional seams, according to the present invention, and the attached drawings, in which:

figure 1 shows a perspective view of a drive assembly of the sewing machine, according to the present invention, adapted to be positioned between the piece in process and the sewing thread;
figure 2 is a plan view of a portion of the drive assembly according to figure 1, according to the present invention;
figure 3 is a sectional view taken along the line A-A of figure 2;
figure 4 is a sectional view taken along the line B-B of figure 2;
figure 5 is a top plan view of the drive assembly according to figure 1, in a rest position, according to the invention;
figure 6 is an enlargement of the detail indicated with H in figure 5;
figure 7 is a plan view from the top of the drive assembly of figure 1, in a first operating position, according to the present invention;
figure 8 is an enlargement of the detail indicated with J in figure 7;
fig. 9 is a top plan view of the drive assembly of fig. 1, in a second operating position, according to the present invention;
figure 10 is an enlargement of the detail indicated with K in figure 9;
figure 11 is a partial perspective view of a sewing machine equipped with the drive assembly, according to the present invention, in the rest position of figure 5;
figure 12 is a partial side view and partially in section of the sewing machine according to figure 11, according to the invention;
figure 13 is a partial perspective view of a sewing machine equipped with the drive assembly, according to the present invention, in the operating position of figure 7;
fig. 14 is a partial side view and partly in section of the sewing machine according to fig. 13, according to the invention;
figure 15 is a partial perspective view of a sewing machine equipped with the drive unit, according to the present invention, in the operating position of figure 9;
fig. 16 is a partial side view and partly in section of the sewing machine according to fig. 15, according to the invention.

With reference to the aforementioned figures, in order to avoid excessive thread tensions, which, when processing an ornamental stitch such as the "hand stitch", are undesired, the sewing machine 20 for stitch by hand with a fixed needle, according to the present invention, employs a drive assembly of two shafts 10, 11, which, driven by an electric motor 12 which actuates a rocker system 13, can be inserted alternately between the material (fabric 21) of the piece being machined and thread 22 of the seam, in correspondence with the hole 14 where the needle 23 of the sewing machine 20 runs, so as to create a temporary bigger thickness of the fabric 21 being processed by drawing more yarn to complete the stitch.
The rocker system 13 comprises two sleds 15, which cooperate with a shaped central core 16, which, driven by the electric motor 12, allows to alternately move the shaft 10 or the shaft 11, which can thus be inserted alternately among them, between the material or fabric 21 being processed and the thread 22 of the seam at the hole 14 formed on the plate 17 of the machine 20 where the needle 23 runs.
In particular, as shown in detail in figures 11, 12, 13, 14, 15 and 16, starting from a rest position according to which the drive assembly does not intervene (fig. 11, 12), it is possible to move a first shaft 11, having a smaller diameter with respect to a second shaft 10, towards the stitch area and positioning it below the plate 17 and the fabric 21, in correspondence of the hole 14 formed on the plate 17 where the needle 23 of the sewing machine 20 runs (fig 13, 14).
Similarly, from the rest position or the operating position with the shaft 11 moved forward, it is possible to move only the second shaft 10, with a larger diameter than the shaft 11, to position it below the plate 17 and the fabric 21, in correspondence of the hole 14 formed on the plate 17 where the needle 23 of the sewing machine 20 runs (figures 15, 16).
When a single shaft 10 or 11 is used, it is actuated so as to pass from a rest position to a working position and vice versa; in the working position the shaft 10, 11 is placed below the plate 17 and the fabric 21, in correspondence of the hole 14 where the needle 23 of the machine 20 runs. The insertion of the shaft 10 or 11 allows to create, if necessary, a temporary thickness beyond the plate 17 on which the thread 22 of the seam slides; this makes it possible to call up more thread to complete the lower stitch of the seam.
In fact, once the shaft 10 or 11 has been disengaged, it leaves a more abundant point in thread, avoiding excessive tensions, which, on certain occasions (such as that of the "hand stitches", that is to say the ornamental stitches made from this type of sewing machines), are undesirable.
Similarly, as shown in the attached figures and as already described previously, it is possible to use two shaft 10, 11, which can be inserted alternately with each other and which have a double function, since they have different thicknesses and/or diameters, in order to call more or less thread to complete the lower stitch of the seam according to need.
In particular, a first shaft 11 is thinner to obtain a smaller thickness (and therefore usable for a shorter stitch of the seam), while a second shaft 10 has a greater thickness and can be used in the case of a longer stitching point.
The drive assembly can be actuated, by means of the rocker 13, mechanically (in which case the mechanism can only be used in combination with one of the shafts 10, 11, since the movement is unidirectional) or electronically; in the latter case, the electric motor 12 allows a bidirectional movement and is therefore able to make the assembly work also in the version with two shafts 10, 11.
Figures 5, 6, 11 and 12 show a view of the drive assembly according to the invention in which the two shafts 10, 11 are in rest position and facing the hole 14 where the needle 23 of the sewing machine 20 is inserted, while figures 7, 8, 9, 10, 13, 14, 15 and 16 show relative positions according to which the shafts 10, 11 are moved forward at the hole 14 of the plate 17 where the needle 23 of the machine 20 is inserted; since the shaft 10, 11 have different thicknesses, the displacement at the hole 14 where the needle 23 is inserted, alternatively, of one or the other shaft 10, 11 determines the use for a shorter point (with 'thinner shaft) or longer (with the thicker shaft).
In this way, each shaft 10, 11 being actuated forward and then inserted below the fabric 21 of the garment being machined and the plate 17, with an end located at the hole 14 where the needle is inserted during its advancement in direction perpendicular to the fabric 21, creates a greater "provisional" thickness, recalling more thread to complete the lower stitch; when the shaft 10, 11 is disengaged, being actuated backwards, it leaves a stitch with a more abundant thread, thus avoiding excessive stresses (which, in the case of machining carried out for ornamental stitches, which is the hand stitch carried out from this type of sewing machines, they are undesirable).
The aforesaid device, very simple and functional, allows to perform the sewing operation by choosing to activate or not activate each of the shaft 10, 11 depending on the materials (fabrics) of the garment being worked and the sewing threads to be used (which, for the realization of ornamental stitch, are more and more varied and problematic).
In practice it has been found that the sewing machine according to the invention fully achieves the intended task, as it is able to offer absolute versatility of operation, allowing to manage the ornamental effect of the stitch by hand to the best of the possible conditions.
From the description made, the characteristics of the sewing machine, which is the subject of the present invention is made clear, as well as the advantages are clear.
Finally, it is possible to introduce further embodiments to the sewing machine in question and to the associated drive assembly described, falling under the scope of protection of the appended claims, as it is possible that, in the practical implementation of the invention, the materials, shapes and dimensions can be chosen according to technical needs.

Claims

A sewing machine (20) for decorative and functional seams, apt to make running-stitch and said running-stitch being formed from a single thread (22) of a predetermined length that passes through the edges of a fabric (21) in process for a determined length, so as to arrange alternately on the straight and reverse of the fabric, in a way that the seam stitches, having varying and adjustable length, are alternately visible on one side and on the other side of the fabric, comprising a needle (23) with a vertical axis, arranged perpendicular to a support plate or plaque (17), where it is placed on the fabric (21) to be sewn, and operable with an alternating motion along its vertical axis, in which said sewing machine includes a drive assembly which drives at least one shaft (10, 11) by means of an electric motor (12) which actuates a rocker system (13), between a working position, according to which said at least one shaft (10, 11) is inserted lower to said support plate (17) of the fabric (21) in a prefixed position corresponding to a hole (14) of said plate (17) where said needle (23) runs during its vertical motion, and a rest position, according to which said at least one shaft (10, 11) is dis-inserted from said prefixed position,
characterized in that said rocker system (13) comprises two sleds (15) co-operating with a shaped central core (16), which allows to alternatively move in translation two shafts (10, 11), in order to create a greater provisional thickness of said fabric, drawing more thread to complete a lower stitch.
A sewing machine (20) according to claim 1, characterized in that said two shafts (10, 11) have different thickness and a first shaft (10), thinner, is usable for a shorter seam stitch, while a second shaft (11) having a thicker width is usable for longer seam stitches.
A sewing machine according (20) to at least one of the previous claims, characterized in that said drive assembly is activated in a mechanical way.
A sewing machine (20) according to at least one of the claims from 1 to 3, characterized in that said drive assembly is actuated, by means of said rocker (13), in an electronic way.
A sewing machine (20) according to claim 4, characterized in that said electric motor (12) of said drive assembly allows a bidirectional movement of said two shafts (10, 11).